WorldWideScience

Sample records for net slip rate

  1. Slip rate and tremor genesis in Cascadia

    Science.gov (United States)

    Wech, Aaron G.; Bartlow, Noel M.

    2014-01-01

    At many plate boundaries, conditions in the transition zone between seismogenic and stable slip produce slow earthquakes. In the Cascadia subduction zone, these events are consistently observed as slow, aseismic slip on the plate interface accompanied by persistent tectonic tremor. However, not all slow slip at other plate boundaries coincides spatially and temporally with tremor, leaving the physics of tremor genesis poorly understood. Here we analyze seismic, geodetic, and strainmeter data in Cascadia to observe for the first time a large, tremor-generating slow earthquake change from tremor-genic to silent and back again. The tremor falls silent at reduced slip speeds when the migrating slip front pauses as it loads the stronger adjacent fault segment to failure. The finding suggests that rheology and slip-speed-regulated stressing rate control tremor genesis, and the same section of fault can slip both with and without detectable tremor, limiting tremor's use as a proxy for slip.

  2. Imbricated slip rate processes during slow slip transients imaged by low-frequency earthquakes

    Science.gov (United States)

    Lengliné, O.; Frank, W. B.; Marsan, D.; Ampuero, J.-P.

    2017-10-01

    Low Frequency Earthquakes (LFEs) often occur in conjunction with transient strain episodes, or Slow Slip Events (SSEs), in subduction zones. Their focal mechanism and location consistent with shear failure on the plate interface argue for a model where LFEs are discrete dynamic ruptures in an otherwise slowly slipping interface. SSEs are mostly observed by surface geodetic instruments with limited resolution and it is likely that only the largest ones are detected. The time synchronization of LFEs and SSEs suggests that we could use the recorded LFEs to constrain the evolution of SSEs, and notably of the geodetically-undetected small ones. However, inferring slow slip rate from the temporal evolution of LFE activity is complicated by the strong temporal clustering of LFEs. Here we apply dedicated statistical tools to retrieve the temporal evolution of SSE slip rates from the time history of LFE occurrences in two subduction zones, Mexico and Cascadia, and in the deep portion of the San Andreas fault at Parkfield. We find temporal characteristics of LFEs that are similar across these three different regions. The longer term episodic slip transients present in these datasets show a slip rate decay with time after the passage of the SSE front possibly as t - 1 / 4. They are composed of multiple short term transients with steeper slip rate decay as t-α with α between 1.4 and 2. We also find that the maximum slip rate of SSEs has a continuous distribution. Our results indicate that creeping faults host intermittent deformation at various scales resulting from the imbricated occurrence of numerous slow slip events of various amplitudes.

  3. Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia)

    Science.gov (United States)

    Prentice, Carol S.; Rizza, M.; Ritz, J.F.; Baucher, R.; Vassallo, R.; Mahan, S.

    2011-01-01

    We carried out morphotectonic studies along the left-lateral strike-slip Bogd Fault, the principal structure involved in the Gobi-Altay earthquake of 1957 December 4 (published magnitudes range from 7.8 to 8.3). The Bogd Fault is 260 km long and can be subdivided into five main geometric segments, based on variation in strike direction. West to East these segments are, respectively: the West Ih Bogd (WIB), The North Ih Bogd (NIB), the West Ih Bogd (WIB), the West Baga Bogd (WBB) and the East Baga Bogd (EBB) segments. Morphological analysis of offset streams, ridges and alluvial fans—particularly well preserved in the arid environment of the Gobi region—allows evaluation of late Quaternary slip rates along the different faults segments. In this paper, we measure slip rates over the past 200 ka at four sites distributed across the three western segments of the Bogd Fault. Our results show that the left-lateral slip rate is∼1 mm yr–1 along the WIB and EIB segments and∼0.5 mm yr–1 along the NIB segment. These variations are consistent with the restraining bend geometry of the Bogd Fault. Our study also provides additional estimates of the horizontal offset associated with the 1957 earthquake along the western part of the Bogd rupture, complementing previously published studies. We show that the mean horizontal offset associated with the 1957 earthquake decreases progressively from 5.2 m in the west to 2.0 m in the east, reflecting the progressive change of kinematic style from pure left-lateral strike-slip faulting to left-lateral-reverse faulting. Along the three western segments, we measure cumulative displacements that are multiples of the 1957 coseismic offset, which may be consistent with a characteristic slip. Moreover, using these data, we re-estimate the moment magnitude of the Gobi-Altay earthquake at Mw 7.78–7.95. Combining our slip rate estimates and the slip distribution per event we also determined a mean recurrence interval of∼2500

  4. Determination of the of rate cross slip of screw dislocations

    DEFF Research Database (Denmark)

    Vegge, Tejs; Rasmussen, Torben; Leffers, Torben

    2000-01-01

    The rate for cross slip of screw dislocations during annihilation of screw dipoles in copper is determined by molecular dynamics simulations. The temperature dependence of the rate is seen to obey an Arrhenius behavior in the investigated temperature range: 225-375 K. The activation energy...

  5. Extreme multi-millennial slip rate variations on the Garlock fault, California: geomorphology and geochronology of slip rate constraints

    Science.gov (United States)

    Rhodes, Edward; Dolan, James; McGill, Sally; McAuliffe, Lee; Zinke, Robert

    2016-04-01

    Combining existing paleoseismology with new geomorphic constraints for the same part of the Central Garlock fault in California, USA, allows us to demonstrate pronounced variations in slip rate during the Holocene for this left-lateral strike-slip system. Our results have basic implications for understanding how faults store and release strain energy in large earthquakes, and for Probabilistic Seismic Hazard Assessment (PSHA). A series of well-preserved fluvial terraces within alluvial fans provide offset markers, and newly developed single grain K-feldspar IRSL dating allows us to constrain depositional ages and subsequent erosion of terrace risers with good precision, using multiple samples from several different locations. This new dating approach has wide applicability for paleoseismology and slip rate studies, besides understanding environmental response to climatic events; agreement with independent age control provided by C-14 and Be-10 profiles comes from sites in the USA, Mexico, Tibet and Mongolia. Sediments dominated by a range of grain sizes from silt to boulders can be dated, and the technique is often applicable in locations where quartz OSL does not work well. We examine the interplay and coupling between climate and tectonics at millennial timescales, along with sedimentary and geomorphic responses, and consider how our understanding of fault dynamics can be improved with the benefit of these new approaches.

  6. The Van Fault, Eastern Turkey: A Preliminary Geological Slip Rate

    Science.gov (United States)

    Mackenzie, D.; Elliott, J. R.; Altunel, E.; Kurban, Y.; Walker, R. T.; Parsons, B.

    2014-12-01

    We present a preliminary quaternary slip-rate study on the Van fault, the source of the 2011 Mw7.1 reverse-slip earthquake which caused heavy damage to the cities of Van and Ercis, eastern Turkey. From the InSAR solution, we see a strong depth cut-off at 10km depth, above which there was no slip on the fault. We have carried out an investigation of the geomorphological expression of the fault in quaternary material, to determine whether the fault reaches the surface and, if so, whether this upper section could fail in an earthquake. On the western segment of the Van fault, we observe quaternary scarps coincident with the surface projection of the fault segment identified by InSAR, which displace quaternary alluvial fan and lake-bed deposits. These are coincident with the observation of fault gouge in quaternary deposits at a road cutting, providing evidence for a fault reaching the surface and suggesting that the upper section is capable of rupturing seismically. We use structure-from-motion photogrammetry, differential GPS and terrestrial LiDAR to determine offsets on two generations of fault scarps, and the creep offsets from the period following the earthquake. Preliminary radiocarbon and OSL dates from two uplifted terrace surfaces allow us to estimate a late quaternary geological slip-rate for the fault. Following the GPS and InSAR solution of Dogan et al. 2014 (GRL v41,i7), we also present field evidence and satellite image observations confirming the presence of a splay fault within the northern suburbs of Van city, which experienced creep following the 2011 earthquake. This fault is observed to be particularly evident in the early high resolution satellite imagery from the declassified CORONA missions, highlighting the potential for these datasets in identifying faults in areas now covered by urban sprawl. It remains unclear whether this fault could fail seismically. The fault which failed in 2011 is a north dipping reverse fault, unmapped prior to the

  7. Comparison of Geodetic and Late Pleistocene Slip Rates for the Southern Dead Sea Fault System

    Science.gov (United States)

    Cochran, W. J.; Gomez, F.; Abu Rajab, J. S.; Al-Tarazi, E.

    2012-12-01

    Comparisons of short-term (geodetic) and Late Quaternary slip rates have been used to assess time-variable fault kinematics along various active faults, globally. Differences between such types slip rates may have implications for crustal rheology and/or temporal variations in plate motion. This research aims to compare the geodetically-derived slip rates with slip rates based on Late Pleistocene landforms along the southern Dead Sea fault system (DSFS). The DSFS is an active, left-lateral transform that accommodates differential movement between the Arabian and Sinai plates. A number of slip rates have been previously reported ranging from 2 to 6mm/yr. However, comparison of various slip rates requires ensuring that associated uncertainties are assessed using a standard. New GPS velocities from Jordan are combined with other available GPS data, and are used to model slip rates using elastic block models. Resulting slip rates are 4.3 to 5.3 mm/yr with fault locking depths of 8 - 15 km. Late Pleistocene rates are assessed from published observations, as well as new data. New mapping of offset alluvial fans in the southern Wadi Araba was facilitated by multi-spectral imagery and high-resolution digital elevation model. These fans correlate with regional aggradation events, with the resulting Late Pleistocene slip rates ranging from 4.2 to 5.1 mm/yr. Statistically, the geodetic and neotectonic slip rates are identical. Additionally, a 3-dimensional slip vector for the last earthquake in the northern Wadi Araba is constructed using close-range photogrammetry of a faulted Byzantine aqueduct that indicates both horizontal and vertical displacements. Previous studies suggested characteristic earthquake slip, so slip rates and this slip vector provide a means of assessing mean EQ recurrence interval, as well as the role of earthquakes in constructing the long-term topography along this part of the transform.

  8. Dependence of Strain Rate Sensitivity on the Slip System: A Molecular Dynamics Simulation

    Science.gov (United States)

    Movahedi-Rad, A.; Alizadeh, R.

    2017-11-01

    The strain rate of deformation might affect mechanical properties of metallic materials, especially at elevated temperatures. Due to the nature of dislocation slip, it is anticipated that strain rate sensitivity (SRS) depends on the slip system. While the dependency of SRS on the temperature and strain rate of the deformation is well recognized, its dependence on the slip system is not well understood. Accordingly, the molecular dynamics simulation was used to investigate the dependence of strain rate sensitivity of pure Al single crystals on the slip system. In this study, the embedded atom method (EAM) potential for Al was employed. SRS and shear strength of the material were studied in four different slip systems and at two temperatures of 300 and 500 K. It was found that SRS of the material depends on the slip system in addition to the temperature, and SRS was higher in less compact systems with more difficult slip. The dislocation theories were used to rationalize the simulation results.

  9. Fault slip rates from three-dimensional models of the Los Angeles metropolitan area, California

    Science.gov (United States)

    Cooke, Michele L.; Marshall, Scott T.

    2006-11-01

    We present results from the first mechanical model of active tectonics in the Los Angeles region to use non-planar, geologically representative fault surfaces compiled by the Southern California Earthquake Center Community Fault Model. The fault slip rates from our three-dimensional model match well the available geologic slip rates. Discrepancies in reverse slip along the Upper Elysian Park fault and strike-slip along the Raymond fault may reflect imprecise knowledge of local fault geometry. Discrepancy in the average dip slip rate along the Palos Verdes fault reveals variations in dip slip along that surface; model predictions at the location of the geological investigation have good match to geologic data. The validated model is used to estimate dip and strike slip rates for 26 active faults in the Los Angeles metropolitan region, many of which are otherwise unconstrained by geologic evidence.

  10. Slow slip rate and excitation efficiency of deep low-frequency tremors beneath southwest Japan

    Science.gov (United States)

    Daiku, Kumiko; Hiramatsu, Yoshihiro; Matsuzawa, Takanori; Mizukami, Tomoyuki

    2018-01-01

    We estimated the long-term average slip rate on the plate interface across the Nankai subduction zone during 2002-2013 using deep low-frequency tremors as a proxy for short-term slow slip events based on empirical relations between the seismic moment of short-term slow slip events and tremor activities. The slip rate in each region is likely to compensate for differences between the convergence rate and the slip deficit rate of the subducting Philippine Sea plate estimated geodetically, although the uncertainty is large. This implies that the strain because of the subduction of the plate is partially stored as the slip deficit and partially released by slow slip events during the interseismic period. The excitation efficiency of the tremors for the slow slip events differs among regions: it is high in the northern Kii region. Some events in the western Shikoku region show a somewhat large value. Antigorite serpentinite of two types exists in the mantle wedge beneath southwest Japan. Slips with more effective excitation of tremors presumably occur in high-temperature conditions in the antigorite + olivine stability field. Other slip events with low excitation efficiency are distributed in the antigorite + brucite stability field. Considering the formation reactions of these minerals and their characteristic structures, events with high excitation efficiency can be correlated with a high pore fluid pressure condition. This result suggests that variation in pore fluid pressure on the plate interface affects the magnitude of tremors excited by slow slip events.

  11. Offset of latest pleistocene shoreface reveals slip rate on the Hosgri strike-slip fault, offshore central California

    Science.gov (United States)

    Johnson, Samuel Y.; Hartwell, Stephen R.; Dartnell, Peter

    2014-01-01

    The Hosgri fault is the southern part of the regional Hosgri–San Gregorio dextral strike‐slip fault system, which extends primarily in the offshore for about 400 km in central California. Between Morro Bay and San Simeon, high‐resolution multibeam bathymetry reveals that the eastern strand of the Hosgri fault is crossed by an ∼265  m wide slope interpreted as the shoreface of a latest Pleistocene sand spit. This sand spit crossed an embayment and connected a western fault‐bounded bedrock peninsula and an eastern bedrock highland, a paleogeography resembling modern coastal geomorphology along the San Andreas fault. Detailed analysis of the relict shoreface with slope profiles and slope maps indicates a lateral slip rate of 2.6±0.9  mm/yr, considered a minimum rate for the Hosgri given the presence of an active western strand. This slip rate indicates that the Hosgri system takes up the largest share of the strike‐slip fault budget and is the most active strike‐slip fault west of the San Andreas fault in central California. This result further demonstrates the value and potential of high‐resolution bathymetry in characterization of active offshore faults.

  12. Slip-rate-dependent melt extraction at oceanic transform faults

    Science.gov (United States)

    Bai, Hailong; Montési, Laurent G. J.

    2015-02-01

    Crustal thickness differences between oceanic transform faults and associated mid-ocean ridges may be explained by melt migration and extraction processes. Slow-slipping transform faults exhibit more positive gravity anomalies than the adjacent spreading centers, indicating relative thin crust in the transform domain, whereas at intermediate-spreading and fast-spreading ridges transform faults are characterized by more negative gravity anomalies than the adjacent spreading centers, indicating thick crust in the transform domain. We present numerical models reproducing these observations and infer that melt can be extracted at fast-slipping transforms, but not at slow-slipping ones. Melt extraction is modeled as a three-step process. (1) Melt moves vertically through buoyancy-driven porous flow enhanced by subvertical dissolution channels. (2) Melt accumulates in and travels along a decompaction channel lining a low-permeability barrier at the base of the thermal boundary layer. (3) Melt is extracted to the surface when it enters a melt extraction zone. A melt extraction width of 2-4 km and a melt extraction depth of 15-20 km are needed to fit the tectonic damages associated with oceanic plate boundaries that reach into the upper mantle. Our conclusions are supported by the different degrees of magmatic activities exhibited at fast-slipping and slow-slipping transforms as reflected in geological features, geochemical signals, and seismic behaviors. We also constrain that the maximum lateral distance of crust-level dike propagation is about 50-70 km.

  13. Duration of slip-resistant shoe usage and the rate of slipping in limited-service restaurants: results from a prospective and crossover study.

    Science.gov (United States)

    Verma, Santosh K; Zhao, Zhe; Courtney, Theodore K; Chang, Wen-Ruey; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Perry, Melissa J

    2014-01-01

    Several studies have indicated that slip-resistant shoes may have a positive effect on reducing the risk of slips and falls, a leading cause of injury at work. Few studies, however, have examined how duration of shoe usage affects their slip-resistance properties. This study examined the association between the duration of slip-resistant shoes usage and the self-reported rate of slipping in limited-service restaurant workers. A total of 475 workers from 36 limited-service restaurants in the USA were recruited to participate in a 12-week prospective study of workplace slipping. Of the 475 participants, 83 reported changing to a new pair of shoes at least once during the 12-week follow-up. The results show that slip-resistant shoes worn for less than six months were moderately more effective than those worn for more than six months. Changing to a new pair of shoes among those wearing slip-resistant shoes at baseline was associated with a 55% reduction in the rate of slipping (RR = 0.45, 95% CI = 0.23-0.89). Further research is needed to develop criteria for the replacement of slip-resistant shoes.

  14. Variable slip-rate and slip-per-event on a plate boundary fault: The Dead Sea fault in northern Israel

    Science.gov (United States)

    Wechsler, Neta; Rockwell, Thomas K.; Klinger, Yann

    2018-01-01

    We resolved displacement on buried stream channels that record the past 3400 years of slip history for the Jordan Gorge (JGF) section of the Dead Sea fault in Israel. Based on three-dimensional (3D) trenching, slip in the past millennium amounts to only 2.7 m, similar to that determined in previous studies, whereas the previous millennium experienced two to three times this amount of displacement with nearly 8 m of cumulative slip, indicating substantial short term variations in slip rate. The slip rate averaged over the past 3400 years, as determined from 3D trenching, is 4.1 mm/yr, which agrees well with geodetic estimates of strain accumulation, as well as with longer-term geologic slip rate estimates. Our results indicate that: 1) the past 1200 years appear to significantly lack slip, which may portend a significant increase in future seismic activity; 2) short-term slip rates for the past two millennia have varied by more than a factor of two and suggest that past behavior is best characterized by clustering of earthquakes. From these observations, the earthquake behavior of the Jordan Gorge fault best fits is a ;weak segment model; where the relatively short fault section (20 km), bounded by releasing steps, fails on its own in moderate earthquakes, or ruptures with adjacent segments.

  15. Frictional processes in smectite-rich gouges sheared at slow to high slip rates

    Science.gov (United States)

    Aretusini, Stefano; Mittempergher, Silvia; Gualtieri, Alessandro; Di Toro, Giulio

    2015-04-01

    The slipping zones of shallow sections of megathrusts and of large landslides are often smectite-rich (e.g., montmorillonite type). Consequently, similar "frictional" processes operating at high slip rates (> 1 m/s) might be responsible of the large slips estimated in megathrust (50 m for the 2011 Tohoku Mw 9.1 earthquake) and measured in large landslides (500 m for the 1963 Vajont slide, Italy). At present, only rotary shear apparatuses can reproduce simultaneously the large slips and slip rates of these events. Noteworthy, the frictional processes proposed so far (thermal and thermochemical pressurization, etc.) remain rather obscure. Here we present preliminary results obtained with the ROtary Shear Apparatus (ROSA) installed at Padua University. Thirty-one experiments were performed at ambient conditions on pure end-members of (1) smectite-rich standard powders (STx-1b: ~68 wt% Ca-montmorillonite, ~30 wt% opal-CT and ~2 wt% quartz), (2) quartz powders (qtz) and (3) on 80:20 = Stx-1b:qtz mixtures. The gouges were sandwiched between two (1) hollow (25/15 mm external/internal diameter) or (2) solid (25 mm in diameter) stainless-steel made cylinders and confined by inner and outer Teflon rings (only outer for solid cylinders). Gouges were sheared at a normal stress of 5 MPa, slip rates V from 300 μm/s to 1.5 m/s and total slip of 3 m. The deformed gouges were investigated with quantitative (Rietveld method with internal standard) X-ray powder diffraction (XRPD) and Scanning Electron Microscopy (SEM). In the smectite-rich standard endmember, (1) for 300 μm/s ≤ V ≤ 0.1 m/s, initial friction coefficient (μi) was 0.6±0.05 whereas the steady-state friction coefficient (μss) was velocity and slip strengthening (μss 0.85±0.05), (2) for 0.1 m/s 0.8 m/s, velocity and slip weakening (μi = 0.7±0.1 and μss = 0.25±0.05). In the 80:20 Stx-1b:qtz mixtures, (1) for 300 μm/s ≤ V ≤ 0.1 m/s, μi ranged was 0.7±0.05 and increased with slip to μss = 0.77±0

  16. Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling

    Science.gov (United States)

    Liu, Y.; Deng, K.; Harrington, R. M.; Clerc, F.

    2016-12-01

    Solid matrix stress change and pore pressure diffusion caused by fluid injection has been postulated as key factors for inducing earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with poroelastic stress perturbations from multi-stage hydraulic fracturing scenarios. We apply the physics-based model to the 2013-2015 earthquake sequences near Fox Creek, Alberta, Canada, where three magnitude 4.5 earthquakes were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated from the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model, we find that slip on the fault evolves from aseismic to seismic in a manner similar to the onset of seismicity. For a 15-stage hydraulic fracturing that lasted for 10 days, modeled fault slip rate starts to accelerate after 3 days of fracking, and rapidly develops into a seismic event, which also temporally coincides with the onset of induced seismicity. The poroelastic stress perturbation and consequently fault slip rate continue to evolve and remain high for several weeks after hydraulic fracturing has stopped, which may explain the continued seismicity after shut-in. In a comparison numerical experiment, fault slip rate quickly decreases to the interseismic level when stress perturbations are instantaneously returned to zero at shut-in. Furthermore, when stress perturbations are removed just a few hours after the fault slip rate starts to accelerate (that is, hydraulic fracturing is shut down prematurely), only aseismic slip is observed in the model. Our preliminary results thus suggest the design of fracturing duration and flow

  17. Apparent late Quaternary fault slip rate increase in the southwestern Lower Rhine Graben, central Europe

    Science.gov (United States)

    Gold, Ryan D.; Friedrich, Anke M.; Kubler, Simon; Salamon, Martin

    2017-01-01

    In regions of low strain, long earthquake recurrence intervals (104–106  yrs) and erosive processes limit preservation of Quaternary markers suitable for distinguishing whether faults slip at uniform or secularly varying rates. The Lower Rhine graben in the border region of Germany, The Netherlands, and Belgium provides a unique opportunity to explore Quaternary slip‐rate variations in a region of low strain using the basal (2.29±0.29  Ma) and surface (700±80  ka) contacts of the regionally extensive main terrace (“Hauptterrasse”), deposited by the Rhine and Maas Rivers. These surfaces are vertically offset 3–140 m and 0–68 m, respectively, across individual fault strands within a distributed network of northwest‐trending, slow‐slipping (light detection and ranging (lidar)‐derived bare‐earth digital terrain models, which we synthesize with existing constraints on the offset basal contact of this fluvial deposit (n=91 collocated sites with displacement constraints). We find that >80% of the sites record an apparent increase in slip rate for the more recent interval from 700 ka to present, which corresponds to a period of increased uplift of the nearby Rhenish Massif and regional volcanism. However, the apparent increase in slip rate could result, in part, from erosion of the footwall surface below the main terrace, leading to an apparent displacement that is smaller than the total vertical offset since the start of the Quaternary. Prior work focused on characterization of these faults as seismic sources in the Lower Rhine graben has preferentially relied on the average fault‐slip rate constrained using the base of the main terrace. We suggest that average fault‐slip rates calculated using the ∼700  ka main terrace surface are subjected to fewer uncertainties and sample a time interval that is more relevant for seismic‐hazard analysis.

  18. Holocene slip rate of the Hayward fault at Union City, California

    Science.gov (United States)

    Lienkaemper, J.J.; Borchardt, G.

    1996-01-01

    Measured offsets of well-dated alluvial fan deposits near the Masonic Home in Union City constrain Holocene slip rate of the Hayward fault between 7 and 9 mm/yr. Our best minimum geologic slip rate over the past 8.27 ?? 0.08 kyr (i.e., 8270 years) is 8.0 ?? 0.7 mm/yr. A steep stream (its channel cut into bedrock) flows southwest out of the East Bay Hills, crosses the fault, and deposits its load on an alluvial fan. We cut two 5-m-deep, fault-parallel trenches 20-30 m southwest of the main fault through the crest of the fan. Walls of the trenches reveal a series of nested distributary channel fills. These channels had cut into old surfaces that are indicated by paleosols developed on flood silts. We distinguished many channel fills by their shape, clast size, flow direction, elevation, and relation to paleosols, enabling us to correlate them between both trenches. Two distinct episodes of fan deposition occurred during the Holocene. Reconstructing the apex positions of these fan units indicates that about 42 ?? 6 m and 66 ?? 6 m of fault slip has occurred since their inceptions at about 4.58 ?? 0.05 ka, and 8.27 ?? 0.05 ka, respectively. We lowered the age and age uncertainty of the younger unit from earlier reports based on new multiple radiocarbon dates. The 4.58 ka slip rate of 9.2 ?? 1.3 mm/yr is not significantly different at 95% confidence from the 8.27 ka slip rate of 8.0 ?? 0.7 mm/yr. Because current regional strain rates are fully consistent with Neogene plate tectonic rates (Lisowski et al., 1991) and the historic surface rate of creep in Union City is only 4.7 ?? 0.1 mm/yr (Galehouse, 1994), the larger, ???8 mm/yr, Holocene slip rate implies that strain is now accumulating on a locked zone at depth. The 8 mm/yr rate is probably minimal because earlier trenching evidence nearby implies that some unknown additional amount of fault deformation occurs outside of the narrow fault zone assumed in measuring slip. Lienkaemper et al. (1991) suggest that the fast

  19. Flow rate through microfilters: Influence of the pore size distribution, hydrodynamic interactions, wall slip, and inertia

    DEFF Research Database (Denmark)

    Jensen, Kaare Hartvig; Valente, Andre X. C. N.; Stone, Howard A.

    2014-01-01

    to obtain an analytical formula for the pressure drop across the microfilter versus the flow rate that accounts for the non-uniform distribution of pore sizes, the hydrodynamic interactions between the pores given their layout pattern, and wall slip. Further, we discuss inertial effects and their order...

  20. SLIP RATE ESTIMATION FOR VEHICLE STABILITY ENHANCEMENT USING FUZZY BASED ELECTRONIC DIFFERENTIAL CONTROLLER

    National Research Council Canada - National Science Library

    A. RAVI; S. PALANI

    2015-01-01

    .... To enhances the vehicle stability, the performances in terms of optimum value of slip rate and also current, torque, back EMF are obtained by the proposed method. By this investigation, a suitable control strategy has been identified and also experimentally validated.

  1. Monte Carlo simulation for slip rate sensitivity analysis in Cimandiri fault area

    Energy Technology Data Exchange (ETDEWEB)

    Pratama, Cecep, E-mail: great.pratama@gmail.com [Graduate Program of Earth Science, Faculty of Earth Science and Technology, ITB, JalanGanesa no. 10, Bandung 40132 (Indonesia); Meilano, Irwan [Geodesy Research Division, Faculty of Earth Science and Technology, ITB, JalanGanesa no. 10, Bandung 40132 (Indonesia); Nugraha, Andri Dian [Global Geophysical Group, Faculty of Mining and Petroleum Engineering, ITB, JalanGanesa no. 10, Bandung 40132 (Indonesia)

    2015-04-24

    Slip rate is used to estimate earthquake recurrence relationship which is the most influence for hazard level. We examine slip rate contribution of Peak Ground Acceleration (PGA), in probabilistic seismic hazard maps (10% probability of exceedance in 50 years or 500 years return period). Hazard curve of PGA have been investigated for Sukabumi using a PSHA (Probabilistic Seismic Hazard Analysis). We observe that the most influence in the hazard estimate is crustal fault. Monte Carlo approach has been developed to assess the sensitivity. Then, Monte Carlo simulations properties have been assessed. Uncertainty and coefficient of variation from slip rate for Cimandiri Fault area has been calculated. We observe that seismic hazard estimates is sensitive to fault slip rate with seismic hazard uncertainty result about 0.25 g. For specific site, we found seismic hazard estimate for Sukabumi is between 0.4904 – 0.8465 g with uncertainty between 0.0847 – 0.2389 g and COV between 17.7% – 29.8%.

  2. How do "ghost transients" from past earthquakes affect GPS slip rate estimates on southern California faults?

    Science.gov (United States)

    Hearn, E. H.; Pollitz, F. F.; Thatcher, W. R.; Onishi, C. T.

    2013-04-01

    In this study, we investigate the extent to which viscoelastic velocity perturbations (or "ghost transients") from individual fault segments can affect elastic block model-based inferences of fault slip rates from GPS velocity fields. We focus on the southern California GPS velocity field, exploring the effects of known, large earthquakes for two end-member rheological structures. Our approach is to compute, at each GPS site, the velocity perturbation relative to a cycle average for earthquake cycles on particular fault segments. We then correct the SCEC CMM4.0 velocity field for this perturbation and invert the corrected field for fault slip rates. We find that if asthenosphere viscosities are low (3 × 1018 Pa s), the current GPS velocity field is significantly perturbed by viscoelastic earthquake cycle effects associated with the San Andreas Fault segment that last ruptured in 1857 (Mw = 7.9). Correcting the GPS velocity field for this perturbation (or "ghost transient") adds about 5 mm/a to the SAF slip rate along the Mojave and San Bernardino segments. The GPS velocity perturbations due to large earthquakes on the Garlock Fault (most recently, events in the early 1600s) and the White Wolf Fault (most recently, the Mw = 7.3 1952 Kern County earthquake) are smaller and do not influence block-model inverted fault slip rates. This suggests that either the large discrepancy between geodetic and geologic slip rates for the Garlock Fault is not due to a ghost transient or that un-modeled transients from recent Mojave earthquakes may influence the GPS velocity field.

  3. Frictional slip instability in plate-rate laboratory experiments: Observations and mechanisms

    Science.gov (United States)

    Ikari, Matt; Kopf, Achim

    2017-04-01

    Earthquake slip that breaches the Earth's surface represent tremendous hazard, not only from the earthquake itself but also from associated landslides and/or tsunami. Evaluating the possibility of near-surface earthquake slip requires knowledge of how frictionally stable shallow fault materials are. In general, laboratory friction experiments have shown that weak phyllosilicates, which are commonly found in the shallow portions of major faults, tend to be stable and creep. Frictional instability which is favorable for earthquake slip tends to be observed in stronger materials. However, this framework is based primarily on experimental studies performed at intermediate driving velocities of roughly a µm/s to mm/s range. This is much faster than plate convergence rates of several cm/yr, or on the order of nm/s, which represent the natural driving condition on major faults. In this study, we investigate the frictional behavior of natural fault zone materials recovered by scientific drilling projects targeting subduction zones (Japan Trench, Nankai Trough, Costa Rica, Barbados, Cascadia), continental strike-slip faults (San Andreas Fault, Alpine Fault), and a detachment normal fault (Woodlark basin). Our results demonstrate that under naturally slow driving rates, velocity-weakening friction is frequently observed for weak fault materials (friction coefficient data from healing experiments at very long hold times (corresponding with the very slow driving velocities we utilize) indicate advanced healing at longer timescales, which may explain why frictional instability in weak materials requires much slower driving rates.

  4. Snowball gouge-aggregates formed in experimental fault gouges at seismic slip rates

    Science.gov (United States)

    Kim, J. H.; Ree, J. H.; Hirose, T.; Yang, K.; Kim, J. W.

    2015-12-01

    Clay-clast aggregates (CCA) have commonly been reported from experimental and natural fault gouges, but their formation process and mechanical meaning are not so clear. We call CCA snowball gouge aggregate (SGA) since its formation process is similar to that of snowball (see below) and CCA-like structure has been reported also from pure quartz and pure calcite gouges. Here, we discuss the formation process of SGA and its implication for faulting from experimental results of simulated gouges. We conducted high-velocity rotary shear experiments on Ca-bentonite gouges at a normal stress of 1 MPa, slip rate of 1.31 m/s, room temperature and room humidity conditions. Ca-bentonite gouge consists of montmorillonite (>95%) and other minor minerals including quartz and plagioclase. Upon displacement, the friction abruptly increases to the 1st peak (friction coefficient μ≈ 0.7) followed by slip weakening to reach a steady state (μ≈ 0.25~0.3). The simulated fault zone can be divided into slip-localization zone (SLZ) and low-slip-rate zone (LSZ) based on grain size. Spherical SGAs with their size ranging from 1 to 100 μm occur only in LSZ, and their proportion is more than 90%. Two types of SGA occur; SGA with and without a central clast. Both types of SGA show a concentric layering defined by the alternation of pore-rich (1-1.5 μm thick) and pore-poor layers (1.5-2 μm thick). Clay minerals locally exhibit a preferred orientation with their basal plane parallel to the layer boundary. We interpret that the pore-poor layers are clay-accumulated layers formed by rolling of SGA nuclei, and pore-rich layers correspond to the boundary between accumulated clay layers. Water produced from dehydration of clays due to frictional heating presumably acts as an adhesion agent of clay minerals during rolling of SGA. Since the number of layers within each SGA represents the number of rolling, the minimum displacement estimated from the number of layers and layer thickness of the

  5. Near-net shape manufacture of B4C–Co and ZrC–Co composites by slip casting and pressureless sintering

    DEFF Research Database (Denmark)

    Ortiz, Angel L.; Leal, Victor Manuel Candelario; Moreno, Rodrigo

    2017-01-01

    Fabrication of near-net shaped B4C–Co and ZrC–Co composites by slip casting and pressureless sintering is described. It is shown how B4C–Co and ZrC–Co concentrated suspensions can be prepared by aqueous colloidal processing, and optimized (in terms of pH, deflocculant contents, and sonication tim...... is given for these observations, and general implications are discussed for the near-net shape manufacture of these and similar carbide-metal composites for use in engineering applications....

  6. Fault slip rate estimates for southwestern US from GPS data and non-block viscoelastic sheet

    Science.gov (United States)

    Chuang, R. Y.; Johnson, K. M.

    2012-12-01

    Fault slip rate estimates from geodetic data are becoming increasingly important for earthquake hazard studies. In order to estimate fault slip rates, GPS-constrained kinematic models such as elastic block models are widely used. However, kinematic block models are inherently non-unique and provide limited insight into the mechanics of deformation. Furthermore, assumed discrete tectonic blocks may not exist everywhere as not every region of the western US displays mature, through-going geologic structures that naturally divide the crust into tectonic blocks. For example, the eastern California shear zone and regions of the Basin and Range Province are best described as broad zones of interacting, discontinuous fault strands. We are building towards mechanical models of present-day surface motions in which deformation is a response to plate boundary forces, gravitational loading, and rheological properties of the lithosphere. To model fault slip rates in the southwestern US, we populate an elastico-visco thin sheet (plane stress) with thin viscous shear zones (faults) and impose far-field plate motions and gravitational loading to compute the long-term fault slip rates and crustal motions. Interseismic deformation due to locking of faults is modeled with backslip on dislocations in an elastic half-space or in an elastic plate over a viscoelastic half-space. The total present-day deformation field (long-term plus intersesismic) is compared with the GPS-derived velocity field and the model stress tensor is compared with the stress state inferred from stress-inversions of focal mechanism data.

  7. Paleoseismology and slip rate of the western Tianjingshan fault of NE Tibet, China

    Science.gov (United States)

    Li, Xinnan; Li, Chuanyou; Wesnousky, Steven G.; Zhang, Peizhen; Zheng, Wenjun; Pierce, Ian K. D.; Wang, Xuguang

    2017-09-01

    We present results from a detailed investigation of the horizontal displacement distribution, timing of paleoearthquakes and left-lateral slip rate on the western Tianjingshan fault. Measurements of 240 offset streams and ridges confirm that the fault is left-lateral and record evidence of repeated ∼3-4 m coseismic offsets along the 60-km-long fault. This suggests that ∼6 earthquakes may have occurred along the entire western Tianjingshan fault with repeated occurrence of earthquakes of Mw 7.2-7.5. Structural and stratigraphic relationships exposed in our five trenches in combination with previously reported studies further indicate that the fault has ruptured in as many as six paleoearthquakes since the late Quaternary. Paleoseismic data show that the average recurrence interval for Holocene earthquakes is approximately 5,000 yr. The most recent earthquake along the western Tianjingshan fault occurred ∼1.2 ± 0.1 kyr BP, indicating that this fault segment did not rupture in the M 7.5 historical earthquake of 1709 that ruptured the central Tianjingshan fault. We estimate that the Holocene slip rate of the western Tianjingshan fault is ∼1.1-1.2 mm/yr based on measurements of the age and offset of stream channels. Compared with the relatively fast slip rate of the Haiyuan fault (∼4-6 mm/yr), we suggest that the Tianjingshan fault acts as an essential active fault accommodating the sinistral displacement and crustal shortening deformation in NE Tibet.

  8. Amorphization and Frictional Processes in Smectite-Quartz Gouge Mixtures Sheared from Sub-seismic to Seismic Slip Rates

    Science.gov (United States)

    Aretusini, S.; Mittempergher, S.; Spagnuolo, E.; Di Toro, G.; Gualtieri, A.; Plümper, O.

    2015-12-01

    Slipping zones in shallow sections of megathrusts and large landslides are often made of smectite and quartz gouge mixtures. Experiments aimed at investigating the frictional processes operating at high slip rates (>1 m/s) may unravel the mechanics of these natural phenomena. Here we present a new dataset obtained with two rotary shear apparatus (ROSA, Padua University; SHIVA, INGV-Rome). Experiments were performed at room humidity and temperature on four mixtures of smectite (Ca-Montmorillonite) and quartz with 68, 50, 25, 0 wt% of smectite. The gouges were slid for 3 m at normal stress of 5 MPa and slip rate V from 300 µm/s to 1.5 m/s. Temperature during the experiments was monitored with four thermocouples and modeled with COMSOL Multiphysics. In smectite-rich mixtures, the friction coefficient µ evolved with slip according to three slip rate regimes: in regime 1 (V0.3 m/s) µ had strong slip-weakening behavior. Instead, in quartz-rich mixtures the gouge had a monotonic slip-weakening behavior, independently of V. Temperature modelling showed that the fraction of work rate converted into heat decreased with increasing smectite content and slip rate. Quantitative X-ray powder diffraction (Rietveld method) indicates that the production of amorphous material from smectite breakdown increased with frictional work but was independent of work rate. Scanning Electron Microscopy investigation evidenced strain localization and presence of dehydrated clays for V≥0.3 m/s; instead, for Vfrictional weakening. Instead, slip-weakening was concomitant to strain localization and possible vaporization of water adsorbed on smectite grain surfaces.

  9. Vertical slip rates of active faults of southern Albania inferred from river terraces

    Directory of Open Access Journals (Sweden)

    Oswaldo Guzmán

    2014-02-01

    Full Text Available Fluvial terraces of Shkumbin, Devoll, Osum and Vjosa rivers (southern Albania and northwestern Greece are studied in order to quantify the vertical slip rates of the large active faults of the Dinaric-Albanic-Hellenic Alpine fold belt. The spatial and temporal variations of the incision rates along these rivers were estimated from the geomorphological mapping of the Quaternary sediments, the geometry and the dating of the terraces. Eleven terraces levels were identified in Albania from 68 geochronological ages already published or acquired for this work. The five lower terraces of the four studied rivers are well dated (10 new and 23 already published ages. These terraces are younger than 30 ka and their remnants are numerous. Their restoration allows estimating the regional trend of incision rate and the identification of local shifts. We argue that these shifts are linked to the active tectonics when they coincide with the faults already mapped by previous authors. Vertical slip rates for eight active faults in southern Albania are thus estimated for the last 19 ka and vary from ~0.1 to ~2 mm/a. The Lushnje Tepelene Thrust, that extends more than 120 kilometers, has a throw rate that varies from 0.2 to 0.8 mm/a, whereas the active faults of the extensional domain are segmented but are very active, with throw rates reaching locally 2 mm/a.

  10. Annual variation in the net longshore sediment transport rate

    CSIR Research Space (South Africa)

    Schoonees, JS

    2000-05-01

    Full Text Available from wave data spanning a number of years, or by measuring continuously the longshore transport over a number of years. In both cases, it must be known over how many consecutive years either the computations or the measurements should be done. Ž... the annual variation in the net longshore transport rates over a period of 7 years. In a study Ž . Žby Shi-Leng and Teh-Fu 1987 , a longshore sediment transport formula the Bijker, .1967 method was calibrated against short-term measurements at Nouakchott...

  11. Slip rate gradients along parallel strands of the eastern Altyn Tagh fault confirm modeled rupture behavior at a transpressional bend

    Science.gov (United States)

    Elliott, A. J.; Oskin, M. E.; Liu-Zeng, J.; Shao, Y.; Liu, Z.; Duan, B.

    2014-12-01

    Characterized in sufficient spatial proximity, Holocene fault slip rates may be used to test numerical model predictions of recurrent rupture behavior, including whether fault geometry produces a persistent control on rupture length. We document slip rate gradients along two subparallel strands of the Altyn Tagh fault (ATF) in western China as they pass through the 50-km-long, 15-20° transpressional double-bend at Aksay (~93°E). In the middle of the bend the southern fault (SATF) attains a strike 20° clockwise from regional fault strike, a bend angle that prior model results predict will inhibit throughgoing propagation of rupture. The northern fault (NATF) reaches only 15° clockwise from regional strike, at which angle model results indicate rupture may continue unimpeded. The sum of NATF and SATF slip rates at a given longitude gives the full sinistral slip rate of the ATF. Our mapping, optically stimulated luminescence (OSL), Be-10, and C-14 geochronology, and paleoseismic results show that ruptures have not propagated through the bend on the SATF during at least the past 5-6 earthquake cycles, including the most recent surface rupture, which we have mapped and measured in detail. We map an abrupt west-to-east decline in mid-Holocene slip rate on the SATF from 5 ± 2 mm/yr west of the bend to 0 mm/yr in the middle of the bend. As the SATF straightens out again to the east, slip has largely been transferred to the NATF; a >10.7 ± 0.8 ka alluvial fan on the east side of the bend is offset merely 9.1 ± 1.2 m by the SATF, giving a Holocene slip rate of 0.9 ± 0.3 mm/yr and representing possibly only 2-3 Holocene earthquakes. On the NATF, we document a more gradual decline in slip rate through the bend, from 6.5 ± 2.5 mm/yr in the east to 2-3 mm/yr on the west. Fault morphology and the absence of an abrupt drop in slip rate on the NATF stand in stark contrast to the SATF and indicate that earthquakes on the NATF may span the bend. Our measured gradients in

  12. Lateral Offset Quality Rating along Low Slip Rate Faults: Application to the Alhama de Murcia Fault (SE Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Marta Ferrater

    2015-11-01

    Full Text Available Seismic hazard assessment of strike-slip faults is based partly on the identification and mapping of landforms laterally offset due to fault activity. The characterization of these features affected by slow-moving faults is challenging relative to studies emphasizing rapidly slipping faults. We propose a methodology for scoring fault offsets based on subjective and objective qualities. We apply this methodology to the Alhama de Murcia fault (SE Iberian Peninsula where we identify 138 offset features that we mapped on a high-resolution (0.5 × 0.5 m pixel size Digital Elevation Model (DEM. The amount of offset, the uncertainty of the measurement, the subjective and objective qualities, and the parameters that affect objective quality are independent variables, suggesting that our methodological scoring approach is good. Based on the offset measurements and qualifications we calculate the Cumulative Offset Probability Density (COPD for the entire fault and for each fault segment. The COPD for the segments differ from each other. Tentative interpretation of the COPDs implies that the slip rate varies from one segment to the other (we assume that channels with the same amount of offset were incised synchronously. We compare the COPD with climate proxy curves (aligning using the very limited age control to test if entrenchment events are coincident with climatic changes. Channel incision along one of the traces in Lorca-Totana segment may be related to transitions from glacial to interglacial periods.

  13. The effect of net foreign assets on saving rate

    Directory of Open Access Journals (Sweden)

    Ben David Nissim

    2014-01-01

    Full Text Available Observing empirical data we find that many countries try to delay the decision of increasing saving rate in order to avoid a decrease of the living standards. However the delay leads a deterioration of countries financial stability. We present a simple theoretical model that connects between countries' saving rate and their net foreign assets. Using cross section data set of 135 countries in 2010 we estimated the econometric relation between saving rate in 2010 as dependent variable and two explanatory variables: the current account in 2010 and the aggregated current account during 1980-2010. Our findings show that industrial countries in a bad financial state tend to decrease their saving rate as external debt is larger causing to deterioration in external debt while countries with good financial state tend to increase their saving rate and the tendency increase as financial state becomes better. Only in countries with a very large external debt saving rate tends to grow. The results point that gross foreign debt will keep increasing and will worsen world financial state causing increased risk of getting into a world crisis.

  14. Estimates of fault-slip rates in southern California by using non-block viscoelastic sheet models

    Science.gov (United States)

    Chuang, R. Y.; Johnson, K. M.

    2013-12-01

    Fault slip rate estimates from geodetic data are becoming increasingly important for earthquake hazard studies. In order to estimate fault slip rates, GPS-constrained kinematic models such as elastic block models are widely used. However, kinematic block models are inherently non-unique and provide limited insight into the mechanics of deformation. In addition, assumed discrete tectonic blocks may not exist everywhere as not every region of the western US displays mature, through-going geologic structures that naturally divide the crust into tectonic blocks. For example, the eastern California shear zone and regions of the Basin and Range Province are best described as broad zones of interacting, discontinuous fault strands. We build a mechanical model of present-day surface motions in which deformation is a response to plate boundary forces, gravitational loading, and rheological properties of the lithosphere. To model long-term fault-slip rates in the southwestern US, we populate an elastico-visco thin sheet (plane stress) with thin viscous shear zones (faults) and impose far-field plate motions and gravitational loading to compute the long-term fault slip rates and crustal motions. The mechanical model inherently allows slips along through-going and discontinuous faults and the viscosity of the lithospheric sheet relaxes unreasonable stress build-up. The fault zone viscosity provides resistance and directly relates stress to slip rates. We incorporate static stress on the fault due to regional gravitational potential energy derived from Flesch et al. (2007). We calculate long-term fault-slip rates in southern California and incorporate backslip as interseismic deformation due to locking of faults to compare the total present-day deformation field (long-term plus intersesismic) with the GPS-derived velocity field.

  15. Late Quaternary slip rate determination by CRN dating on the Haiyuan fault, China, and implication for complex geometry fault systems

    Science.gov (United States)

    Matrau, Rémi; Klinger, Yann; Van der Woerd, Jérôme; Liu-Zeng, Jing; Li, Zhanfei; Xu, Xiwei

    2017-04-01

    Late Quaternary slip rate determination by CRN dating on the Haiyuan fault, China, and implication for complex geometry fault systems Matrau Rémi, Klinger Yann, Van der Woerd Jérôme, Liu-Zeng Jing, Li Zhanfei, Xu Xiwei The Haiyuan fault in Gansu Province, China, is a major left-lateral strike-slip fault forming the northeastern boundary of the Tibetan plateau and accommodating part of the deformation from the India-Asia collision. Geomorphic and geodetic studies of the Haiyuan fault show slip rates ranging from 4 mm/yr to 19 mm/yr from east to west along 500 km of the fault. Such discrepancy could be explained by the complex geometry of the fault system, leading to slip distribution on multiple branches. Combining displacement measurements of alluvial terraces from high-resolution Pléiades images and 10Be - 26Al cosmogenic radionuclides (CRN) dating, we bracket the late Quaternary slip rate along the Hasi Shan fault segment (37°00' N, 104°25' E). At our calibration site, terrace riser offsets for 5 terraces ranging from 6 m to 227 m and CRN ages ranging from 6.5±0.6 kyr to 41±4 kyr - yield geological left-lateral slip rates from 2.0 mm/yr to 4.4 mm/yr. We measured consistent terrace riser offset values along the entire 25 km-long segment, which suggests that some external forcing controls the regional river-terrace emplacement, regardless of each specific catchment. Hence, we extend our slip rate determination to the entire Hasi Shan fault segment to be 4.0±1.0 mm/yr since the last 40 kyr. This rate is consistent with other long-term rates of 4 mm/yr to 5 mm/yr east and west of Hasi Shan - as well as geodetic rates of 4 mm/yr to 6 mm/yr west of Hasi Shan. However, Holocene terraces and moraines offsets have suggested higher rates of 15 to 20 mm/yr further west. Such disparate rates may be explained by slip distribution on multiple branches. In particular, the Zhongwei fault splay in the central part of the Haiyuan fault, with a slip rate of 4-5 mm/yr could

  16. Seismicity rate increases associated with slow slip episodes prior to the 2012 Mw 7.4 Ometepec earthquake

    Science.gov (United States)

    Colella, Harmony V.; Sit, Stefany M.; Brudzinski, Michael R.; Graham, Shannon E.; DeMets, Charles; Holtkamp, Stephen G.; Skoumal, Robert J.; Ghouse, Noorulann; Cabral-Cano, Enrique; Kostoglodov, Vladimir; Arciniega-Ceballos, Alejandra

    2017-04-01

    The March 20, 2012 Mw 7.4 Ometepec earthquake in the Oaxaca region of Southern Mexico provides a unique opportunity to examine whether subtle changes in seismicity, tectonic tremor, or slow slip can be observed prior to a large earthquake that may illuminate changes in stress or background slip rate. Continuous Global Positioning System (cGPS) data reveal a 5-month-long slow slip event (SSE) between ∼20 and 35 km depth that migrated toward and reached the vicinity of the mainshock a few weeks prior to the earthquake. Seismicity in Oaxaca is examined using single station tectonic tremor detection and multi-station waveform template matching of earthquake families. An increase in seismic activity, detected with template matching using aftershock waveforms, is only observed in the weeks prior to the mainshock in the region between the SSE and mainshock. In contrast, a SSE ∼15 months earlier occurred at ∼25-40 km depth and was primarily associated with an increase in tectonic tremor. Together, these observations indicate that in the Oaxaca region of Mexico shallower slow slip promotes elevated seismicity rates, and deeper slow slip promotes tectonic tremor. Results from this study add to a growing number of published accounts that indicate slow slip may be a common pre-earthquake signature.

  17. Incremental slip rate and paleoseismic data from the eastern Hope fault, New Zealand: the Hossack and Green Burn sites

    Science.gov (United States)

    Hatem, A. E.; Dolan, J. F.; Langridge, R.; Zinke, R. W.; McGuire, C. P.; Rhodes, E.; Van Dissen, R. J.

    2016-12-01

    We present incremental slip rate and paleo-earthquake data from the Conway segment of the eastern Hope fault, within the Marlborough Fault System (MFS) in the northern South Island of New Zealand. Our incremental slip rate site at Hossack Station is located near the western boundary of the Conway segment (near the Hanmer pull-apart basin), and preserves four offsets of the Hossack Stream channel that range in size from c. 11 to 190 m. Channel cut and fill deposits were exposed in several fault-parallel (channel perpendicular) trenches, and the initiation and abandonment of these offset channels are constrained by >60 radiocarbon ages, yielding four incremental slip rates spanning the Holocene. Our paleoseismologic trench at Green Burn, at the eastern end of the Conway segment near Kaikoura, was excavated across the 5-m-high fault scarp into the adjacent bog deposits. This fault-perpendicular trench revealed evidence for at least four paleo-earthquakes with age constraints provided by >40 radiocarbon dates. These results add to a growing body of slip rate and paleo-earthquake age and displacement data from all four main strike-slip faults that comprise the MFS. Collectively, these observations from the Hope fault are beginning to reveal the detailed system-level behavior of the four main faults in the MFS, with fundamental implications for, among other things, earthquake occurrence and behavior, as well as seismic hazard assessment.

  18. Geodetic Constraints on Fault Slip Rates and Seismic Hazard in the Greater Las Vegas Area

    Science.gov (United States)

    Hammond, W. C.; Kreemer, C.; Blewitt, G.; Broermann, J.; Bennett, R. A.

    2014-12-01

    We address fundamental questions about how contemporary tectonic deformation of the crust in the southern Great Basin occurs in the region around Las Vegas (LV) Nevada, western Arizona and eastern California. This area lies in the intersection of the eastern Walker Lane Belt, southern Great Basin and western Colorado Plateau (CP), sharing features of transtensional and extensional deformation associated with Pacific/North America relative motion. We use GPS data collected from 48 stations of the MAGNET semi-continuous network and 77 stations from continuous networks including BARGEN and EarthScope Plate Boundary Observatory. MAGNET stations have been observed for a minimum of 7 years, while most continuous stations have longer records. From these data we estimate the velocity of crustal motion for all stations with respect to the stable North America reference frame NA12. To correct for transients from recent large earthquakes including the 1999 Hector Mine and 2010 El Mayor-Cucapah events we use models of co- and post-seismic deformation, subtracting the predicted motions from the time series before estimating interseismic stain rates. We find approximately 2 mm/yr of relative motion distributed over 200 km centered on Las Vegas, with a mean strain accumulation rate of 10 × 10-9 yr-1, with lower rates of predominantly extensional strain to the east and higher rates of predominantly shear deformation to the west. The mean strain rate is lower than that of the western Walker Lane but about twice that of eastern Nevada where e.g., the Wells, NV MW 6.0 earthquake occurred in 2008. From this new velocity field we generated a horizontal tensor strain rate map and a crustal block motion model to portray the transition of active strain from the CP into the Walker Lane. For faults in the Las Vegas Valley, including the Eglington Fault and Frenchman Mountain Fault, the observed velocity gradients and model results are consistent with normal slip rates of 0.2 mm/yr, which

  19. Late quaternary slip-rate variations along the Warm Springs Valley fault system, northern Walker Lane, California-Nevada border

    Science.gov (United States)

    Gold, Ryan; dePolo, Craig; Briggs, Richard W.; Crone, Anthony

    2013-01-01

    The extent to which faults exhibit temporally varying slip rates has important consequences for models of fault mechanics and probabilistic seismic hazard. Here, we explore the temporal behavior of the dextral‐slip Warm Springs Valley fault system, which is part of a network of closely spaced (10–20 km) faults in the northern Walker Lane (California–Nevada border). We develop a late Quaternary slip record for the fault using Quaternary mapping and high‐resolution topographic data from airborne Light Distance and Ranging (LiDAR). The faulted Fort Sage alluvial fan (40.06° N, 119.99° W) is dextrally displaced 98+42/-43 m, and we estimate the age of the alluvial fan to be 41.4+10.0/-4.8 to 55.7±9.2  ka, based on a terrestrial cosmogenic 10Be depth profile and 36Cl analyses on basalt boulders, respectively. The displacement and age constraints for the fan yield a slip rate of 1.8 +0.8/-0.8 mm/yr to 2.4 +1.2/-1.1 mm/yr (2σ) along the northern Warm Springs Valley fault system for the past 41.4–55.7 ka. In contrast to this longer‐term slip rate, shorelines associated with the Sehoo highstand of Lake Lahontan (~15.8  ka) adjacent to the Fort Sage fan are dextrally faulted at most 3 m, which limits a maximum post‐15.8 ka slip rate to 0.2  mm/yr. These relations indicate that the post‐Lahontan slip rate on the fault is only about one‐tenth the longer‐term (41–56 ka) average slip rate. This apparent slip‐rate variation may be related to co‐dependent interaction with the nearby Honey Lake fault system, which shows evidence of an accelerated period of mid‐Holocene earthquakes.

  20. A High-Rate, Single-Crystal Model including Phase Transformations, Plastic Slip, and Twinning

    Energy Technology Data Exchange (ETDEWEB)

    Addessio, Francis L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bronkhorst, Curt Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bolme, Cynthia Anne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Explosive Science and Shock Physics Division; Brown, Donald William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Cerreta, Ellen Kathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lebensohn, Ricardo A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lookman, Turab [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Luscher, Darby Jon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Mayeur, Jason Rhea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Morrow, Benjamin M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Rigg, Paulo A. [Washington State Univ., Pullman, WA (United States). Dept. of Physics. Inst. for Shock Physics

    2016-08-09

    An anisotropic, rate-­dependent, single-­crystal approach for modeling materials under the conditions of high strain rates and pressures is provided. The model includes the effects of large deformations, nonlinear elasticity, phase transformations, and plastic slip and twinning. It is envisioned that the model may be used to examine these coupled effects on the local deformation of materials that are subjected to ballistic impact or explosive loading. The model is formulated using a multiplicative decomposition of the deformation gradient. A plate impact experiment on a multi-­crystal sample of titanium was conducted. The particle velocities at the back surface of three crystal orientations relative to the direction of impact were measured. Molecular dynamics simulations were conducted to investigate the details of the high-­rate deformation and pursue issues related to the phase transformation for titanium. Simulations using the single crystal model were conducted and compared to the high-­rate experimental data for the impact loaded single crystals. The model was found to capture the features of the experiments.

  1. Influence of strain rate on the twin and slip activity of a magnesium alloy containing neodymium

    Energy Technology Data Exchange (ETDEWEB)

    Dudamell, N.V. [IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Hidalgo-Manrique, P., E-mail: paloma.hidalgo@imdea.org [IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Chakkedath, A.; Chen, Z.; Boehlert, C.J. [Michigan State University, East Lansing, MI 48824-1226 (United States); Gálvez, F. [ETS Ingenieros de Caminos, Universidad Politécnica de Madrid, 28040 Madrid (Spain); Yi, S.; Bohlen, J.; Letzig, D. [Magnesium Innovation Centre, Helmholtz-Zentrum Geesthacht, 21502 Geesthacht (Germany); Pérez-Prado, M.T. [IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain)

    2013-10-20

    The mechanical behavior of an extruded magnesium–manganese alloy containing 1 wt% of neodymium (MN11) has been investigated at temperatures ranging from room temperature to 400 °C at both quasi-static and dynamic rates. Conventional ex-situ tests, carried out in compression along the extrusion axis (EA), have been combined with in-situ tests in a scanning electron microscope (SEM) in order to elucidate the effect of a rare earth (RE) addition on the dominant deformation mechanisms. An unusually large activity of twinning was observed at room temperature in a wide range of quasi-static rates. Furthermore, the twinning activity has been found to increase at temperatures around 250 °C, where clear signs of dynamic strain aging (DSA) are also apparent. The enhanced twinning activity compared to conventional Mg alloys, not containing RE elements, is attributed to an increase in the critical resolved shear stress of basal slip (CRSS{sub basal}) due to the presence of intermetallic RE-containing particles and to the Nd atoms in solid solution. The surprising decrease of the twinning activity at dynamic rates (∼10{sup 3} s{sup −1}) may be explained by a decrease in the CRSS{sub basal} as the intermetallic RE-containg particles and the Nd solid solution strengthening become less effective with increasing strain rate.

  2. Refining fault slip rates using multiple displaced terrace risers—An example from the Honey Lake fault, NE California, USA

    Science.gov (United States)

    Gold, Ryan D.; Briggs, Richard; Crone, Anthony J.; Duross, Christopher

    2017-01-01

    Faulted terrace risers are semi-planar features commonly used to constrain Quaternary slip rates along strike-slip faults. These landforms are difficult to date directly and therefore their ages are commonly bracketed by age estimates of the adjacent upper and lower terrace surfaces. However, substantial differences in the ages of the upper and lower terrace surfaces (a factor of 2.4 difference observed globally) produce large uncertainties in the slip-rate estimate. In this investigation, we explore how the full range of displacements and bounding ages from multiple faulted terrace risers can be combined to yield a more accurate fault slip rate. We use 0.25-m cell size digital terrain models derived from airborne lidar data to analyze three sites where terrace risers are offset right-laterally by the Honey Lake fault in NE California, USA. We use ages for locally extensive subhorizontal surfaces to bracket the time of riser formation: an upper surface is the bed of abandoned Lake Lahontan having an age of 15.8 ± 0.6 ka and a lower surface is a fluvial terrace abandoned at 4.7 ± 0.1 ka. We estimate lateral offsets of the risers ranging between 6.6 and 28.3 m (median values), a greater than fourfold difference in values. The amount of offset corresponds to the riser's position relative to modern stream meanders: the smallest offset is in a meander cutbank position, whereas the larger offsets are in straight channel or meander point-bar positions. Taken in isolation, the individual terrace-riser offsets yield slip rates ranging from 0.3 to 7.1 mm/a. However, when the offset values are collectively assessed in a probabilistic framework, we find that a uniform (linear) slip rate of 1.6 mm/a (1.4–1.9 mm/a at 95% confidence) can satisfy the data, within their respective uncertainties. This investigation demonstrates that integrating observations of multiple offset elements (crest, midpoint, and base) from numerous faulted and dated terrace risers at closely spaced

  3. Refining fault slip rates using multiple displaced terrace risers-An example from the Honey Lake fault, NE California, USA

    Science.gov (United States)

    Gold, Ryan D.; Briggs, Richard W.; Crone, Anthony J.; DuRoss, Christopher B.

    2017-11-01

    Faulted terrace risers are semi-planar features commonly used to constrain Quaternary slip rates along strike-slip faults. These landforms are difficult to date directly and therefore their ages are commonly bracketed by age estimates of the adjacent upper and lower terrace surfaces. However, substantial differences in the ages of the upper and lower terrace surfaces (a factor of 2.4 difference observed globally) produce large uncertainties in the slip-rate estimate. In this investigation, we explore how the full range of displacements and bounding ages from multiple faulted terrace risers can be combined to yield a more accurate fault slip rate. We use 0.25-m cell size digital terrain models derived from airborne lidar data to analyze three sites where terrace risers are offset right-laterally by the Honey Lake fault in NE California, USA. We use ages for locally extensive subhorizontal surfaces to bracket the time of riser formation: an upper surface is the bed of abandoned Lake Lahontan having an age of 15.8 ± 0.6 ka and a lower surface is a fluvial terrace abandoned at 4.7 ± 0.1 ka. We estimate lateral offsets of the risers ranging between 6.6 and 28.3 m (median values), a greater than fourfold difference in values. The amount of offset corresponds to the riser's position relative to modern stream meanders: the smallest offset is in a meander cutbank position, whereas the larger offsets are in straight channel or meander point-bar positions. Taken in isolation, the individual terrace-riser offsets yield slip rates ranging from 0.3 to 7.1 mm/a. However, when the offset values are collectively assessed in a probabilistic framework, we find that a uniform (linear) slip rate of 1.6 mm/a (1.4-1.9 mm/a at 95% confidence) can satisfy the data, within their respective uncertainties. This investigation demonstrates that integrating observations of multiple offset elements (crest, midpoint, and base) from numerous faulted and dated terrace risers at closely spaced

  4. Sensitivity of Detecting Shallow Slip in Tsunami Earthquakes Using High-Rate Seismogeodetic Displacement and Velocity Waveforms

    Science.gov (United States)

    Saunders, J. K.; Haase, J. S.; Bock, Y.

    2016-12-01

    The shallowest portion of the subduction zone, from the trench to 15 km depth, can facilitate long-duration, moderately sized earthquakes that have anomalously low seismic moment and short-period energy release accompanying large coseismic offsets. Such events have been dubbed `tsunami earthquakes' due to their disproportionately large tsunamis compared to their magnitude. The central portion of the subduction zone ( 15-50 km depth) is associated with generally higher rigidity and is where the majority of great subduction earthquakes nucleate. With increasing earthquake magnitude, the long-period and permanent deformations dominate motions in the near field, making displacement observations ideal for near-field earthquake characterization. In this study, we determine the sensitivity of seismogeodetic (combined high-rate GPS and accelerations) waveforms to slip location (shallow versus deeper slip) for the Cascadia subduction zone in order to assess their usefulness in rapidly determining the potential hazard of tsunami earthquakes with relatively small moment. We generate simple kinematic slip models that exhibit source properties according to the different subduction zone domains: a shallow Mw8 earthquake rupture, representing a tsunami earthquake, and a deeper earthquake of the same magnitude and slip distribution that does not rupture into the shallow portion. We choose rupture speed and slip duration for each simulation based on compilations of kinematic rupture models from past earthquakes. Specifically, the rupture speed is lowered and the slip duration is extended in the shallow earthquake to represent slip in the weaker, sediment-rich region near the trench. We generate synthetic waveforms and compare these displacements and velocities among scenarios to determine where there are differences that constrain the region and amount of slip. We then assess how well the current collocated seismogeodetic network samples the ground motions in critical areas for

  5. Differential Control Strategy based on an Equal Slip Rate for an All-wheel Electricdrive Underground Articulated Dumping Truck

    Directory of Open Access Journals (Sweden)

    Jin Chun

    2014-09-01

    Full Text Available A differential control strategy based on equal slip rates is introduced to improve the steering stability of an all-wheelelectric-drive underground articulated dumping truck. Steering kinematic and dynamic models of the truck are derived to describe the movement relationship and force of the driving wheels. In consideration of the difficulty of obtaining the absolute velocity for an all-wheel-drive truck, an acceleration sensor was set on a test truck, and a kalman filter was applied to obtain the actual value for the truck body. Simulation results for an equal-slip control strategy were compared with experimental results for an equal-torque control strategy. In the simulation, the four-wheel slip rate was 0.08 and the steering system of the truck was stable. The results verify that the equal-slip control strategy makes better use of the ground adhesion coefficient, is able to reasonably distribute drive power, notably reduces tire wear, and improves the use of driving power.

  6. Real-time inversions for finite fault slip models and rupture geometry based on high-rate GPS data

    Science.gov (United States)

    Minson, Sarah E.; Murray, Jessica R.; Langbein, John O.; Gomberg, Joan S.

    2015-01-01

    We present an inversion strategy capable of using real-time high-rate GPS data to simultaneously solve for a distributed slip model and fault geometry in real time as a rupture unfolds. We employ Bayesian inference to find the optimal fault geometry and the distribution of possible slip models for that geometry using a simple analytical solution. By adopting an analytical Bayesian approach, we can solve this complex inversion problem (including calculating the uncertainties on our results) in real time. Furthermore, since the joint inversion for distributed slip and fault geometry can be computed in real time, the time required to obtain a source model of the earthquake does not depend on the computational cost. Instead, the time required is controlled by the duration of the rupture and the time required for information to propagate from the source to the receivers. We apply our modeling approach, called Bayesian Evidence-based Fault Orientation and Real-time Earthquake Slip, to the 2011 Tohoku-oki earthquake, 2003 Tokachi-oki earthquake, and a simulated Hayward fault earthquake. In all three cases, the inversion recovers the magnitude, spatial distribution of slip, and fault geometry in real time. Since our inversion relies on static offsets estimated from real-time high-rate GPS data, we also present performance tests of various approaches to estimating quasi-static offsets in real time. We find that the raw high-rate time series are the best data to use for determining the moment magnitude of the event, but slightly smoothing the raw time series helps stabilize the inversion for fault geometry.

  7. Investigation of transient friction in rock at low to high slip-rates using a new biaxial machine

    Science.gov (United States)

    Saber, O.; Chester, F. M.; Alvarado, J. L.; Barbery, M. R.

    2015-12-01

    Rate-and-state friction (RSF) constitutive relations were developed from experiments on rock that incorporated step-changes in sliding rate at low velocity (rotary shear experiments demonstrate pronounced reduction in friction during sustained sliding at high rates (> 0.1 m/s) that appears distinct from RSF. Developing constitutive relations that can describe the transient friction response during a change from sliding at low rates to high rates is necessary to model earthquake nucleation, rupture propagation, and the diversity in modes of fault slip; however, experimental documentation of transient friction between low and high rates is not generally available. We report the results of experiments using a high-speed biaxial apparatus that achieves velocity-steps from low to high rates with high acceleration (up to 100 G) to investigate transient friction behavior and the viability of RSF relations at intermediate and high sliding velocity. Double-direct (unconfined rock-on-rock) shear experiments on granite (Westerly) and quartz sandstone (Tennessee) were conducted at constant normal stresses of 1-20 MPa. Most experiments involve steady-state frictional sliding at 1 mm/s for several mm of slip followed by a velocity step to constant slip rates of 10 to 1000 mm/s for a total displacement of 4 cm. The experiments demonstrate that a high acceleration step to high velocity under moderate normal stress can lead to rapid dynamic weakening (i.e., a weakening distance of ~1 mm). In granite, the magnitude of steady state friction at high rates is proportional to the rate of frictional work done on the surface, consistent with a flash heating mechanism. In contrast, for the sandstone, steps to high sliding rates resulted in strengthening and a change from stick-slip to stable sliding. The observations are qualitatively consistent with RSF type behaviors; i.e., transient friction consists of an instantaneous increase in friction followed by an exponential decay to a new

  8. Highly Variable Latest Pleistocene-Holocene Incremental Slip Rates on the Awatere Fault at Saxton River, South Island, New Zealand, Revealed by Lidar Mapping and Luminescence Dating

    Science.gov (United States)

    Zinke, Robert; Dolan, James F.; Rhodes, Edward J.; Van Dissen, Russ; McGuire, Christopher P.

    2017-11-01

    Geomorphic mapping using high-resolution lidar imagery and luminescence dating reveal highly variable incremental Holocene-latest Pleistocene slip rates at the well-known Saxton River site along the Awatere fault, a dextral strike-slip fault in the Marlborough Fault System, South Island, New Zealand. Using lidar and field observations, we measured seven fault offsets recorded by fluvial terraces and bedrock markers. Improved dating of the offsets is provided by post-IR-IRSL225 luminescence ages. Incremental slip rates varied from 15 mm/yr over intervals of thousands of years and tens of meters of slip, demonstrating order-of-magnitude temporal variations in rate at a single site. These observations have basic implications for earthquake fault behavior, lithospheric mechanics, discrepancies between geodetic and geologic slip rates, and probabilistic seismic hazard assessment.

  9. Geodesy- and geology-based slip-rate models for the Western United States (excluding California) national seismic hazard maps

    Science.gov (United States)

    Petersen, Mark D.; Zeng, Yuehua; Haller, Kathleen M.; McCaffrey, Robert; Hammond, William C.; Bird, Peter; Moschetti, Morgan; Shen, Zhengkang; Bormann, Jayne; Thatcher, Wayne

    2014-01-01

    The 2014 National Seismic Hazard Maps for the conterminous United States incorporate additional uncertainty in fault slip-rate parameter that controls the earthquake-activity rates than was applied in previous versions of the hazard maps. This additional uncertainty is accounted for by new geodesy- and geology-based slip-rate models for the Western United States. Models that were considered include an updated geologic model based on expert opinion and four combined inversion models informed by both geologic and geodetic input. The two block models considered indicate significantly higher slip rates than the expert opinion and the two fault-based combined inversion models. For the hazard maps, we apply 20 percent weight with equal weighting for the two fault-based models. Off-fault geodetic-based models were not considered in this version of the maps. Resulting changes to the hazard maps are generally less than 0.05 g (acceleration of gravity). Future research will improve the maps and interpret differences between the new models.

  10. Incremental Holocene slip rates from the Hope fault at Hossack Station, Marlborough fault zone, South Island, New Zealand

    Science.gov (United States)

    Hatem, A. E.; Dolan, J. F.; Langridge, R.; Zinke, R. W.; McGuire, C. P.; Rhodes, E. J.; Van Dissen, R. J.

    2015-12-01

    The Marlborough fault system, which links the Alpine fault with the Hikurangi subduction zone within the complex Australian-Pacific plate boundary zone, partitions strain between the Wairau, Awatere, Clarence and Hope faults. Previous best estimates of dextral strike-slip along the Hope fault are ≤ ~23 mm/yr± 4 mm/year. Those rates, however, are poorly constrained and could be improved using better age determinations in conjunction with measurements of fault offsets using high-resolution imagery. In this study, we use airborne lidar- and field-based mapping together with the subsurface geometry of offset channels at the Hossack site 12 km ESE of Hanmer Springs to more precisely determine stream offsets that were previously identified by McMorran (1991). Specifically, we measured fault offsets of ~10m, ~75 m, and ~195m. Together with 65 radiocarbon ages on charcoal, peat, and wood and 25 pending post-IR50-IRSL225 luminescence ages from the channel deposits, these offsets yield three different fault slip rates for the early Holocene, the late Holocene, and the past ca. 500-1,000 years. Using the large number of age determinations, we document in detail the timing of initiation and abandonment of each channel, enhancing the geomorphic interpretation at the Hossack site as channels deform over many earthquake cycles. Our preliminary incremental slip rate results from the Hossack site may indicate temporally variable strain release along the Hope fault. This study is part of a broader effort aimed at determining incremental slip rates and paleo-earthquake ages and displacements from all four main Marlborough faults. Collectively, these data will allow us to determine how the four main Marlborough faults have work together during Holocene-late Pleistocene to accommodate plate-boundary deformation in time and space.

  11. The effect of water on strain localization in calcite fault gouge sheared at seismic slip rates

    Science.gov (United States)

    Rempe, Marieke; Smith, Steven; Mitchell, Thomas; Hirose, Takehiro; Di Toro, Giulio

    2017-04-01

    Strain localization during coseismic slip in fault gouges is a critical mechanical process that has implications for understanding frictional heating, the earthquake energy budget and the evolution of fault rock microstructure. To assess the nature of strain localization during shearing of calcite fault gouges, high-velocity (vmax = 1m /s) rotary-shear experiments at normal stresses of 3-20 MPa were conducted under room-dry and wet conditions on synthetic calcite gouges containing dolomite gouge strain markers. When sheared at 1 m/s, the room-dry gouges showed a prolonged strengthening phase prior to dynamic weakening, whereas the wet gouges weakened nearly instantaneously. Microstructural analysis revealed that a thin (<600 μm) high-strain layer and through-going principal slip surface (PSS) developed after several centimeters of slip in both dry and wet gouges, and that strain localization at 1 m/s occurred progressively and rapidly. The strain accommodated in the bulk gouge layer did not change significantly with increasing displacement indicating that, once formed, the high-strain layer and PSS accommodated most of the displacement. Thus, a substantial strain gradient is present in the gouge layer. In water-dampened gouges, localization likely occurs during and after dynamic weakening. Our results suggest that natural fault zones in limestone are more prone to rapid dynamic weakening if water is present in the granular slipping zones.

  12. Determination of a Holocene Slip Rate on the Puente Hills Blind-Thrust Fault, Los Angeles Basin, California

    Science.gov (United States)

    Christofferson, S. A.; Dolan, J. F.; Shaw, J. H.; Pratt, T. L.

    2001-12-01

    Paleoseismologic observations of slip histories and slip rates of faults that break the surface are available at an ever-increasing rate, but the nature of blind-thrust faults has kept paleoearthquake information on these faults out of reach. The complex network of blind thrust faults beneath the Los Angeles metropolitan region includes the Puente Hills thrust fault (PHT), which extends southeastward for >35 km from beneath downtown Los Angeles into northern Orange County. This thrust is active, as demonstrated by the occurrence of the 1987 Mw 6.0 Whittier Narrows earthquake (Shaw and Shearer 1999). Despite our awareness of the hazard posed by this fault, we do not know its current slip rate or its earthquake history prior to the 1987 event. To determine these critical data, we have begun a two-phase project in which we will acquire high-resolution seismic reflection data and excavate paleoseismologic boreholes and trenches across the zone of active folding associated with major earthquakes on the PHT. We have acquired high-resolution seismic reflection profiles along two transects across the zone of active folding. In our eastern most profile, along Trojan Way in La Mirada, the seismic reflection data show that the locus of active folding extends to 1.5- 2-m-thick reddish-brown argillic horizon. This soil indicates that the geomorphic surface atop the scarp is late Pleistocene in age. The 9 m height of the scarp provides a minimum estimate of total structural relief since stabilization of the ground surface. These observations yield an approximate uplift rate on the order of a few tenths of a mm/yr. Assuming simple hangingwall block translation and given the 19° -22° N dip of the PHT beneath the site, we calculate a minimum average late Pleistocene-Recent dip-slip rate of \\sim 0.2 to 1.1 mm/yr. This slip-rate range is based on our crude age estimates of the late Pleistocene soil. 14C dating of detrital charcoal recovered from the borehole will allow us to

  13. Holocene slip rate and evidences of surface ruptures along the Main Frontal Thrust in Bhutan

    Science.gov (United States)

    Ritz, Jean-François; Berthet, Théo; Pelgay, Phuntsho; Ferry, Mathieu; Drukpa, Dowchu; Cattin, Rodolphe; Chophel, Jamyang; Thinley, Kinzang

    2013-04-01

    On the long term, the Himalayas absorb about 20 mm/yr of the convergence between the India and Eurasia plates. Morphotectonics studies East of Bhutan yielded an Holocene slip rate of 23 ± 6.2 mm/yr consistent with the 21 ± 1.5 mm/yr estimated in Nepal. In the past 1000 years, most of this crustal shortening is accommodated along the Main Frontal Thrust (MFT) by major M≥8 earthquakes. Recent paleoseismic investigations between the meizoseismal areas of the 1934 Bihar-Nepal and 1950 Assam earthquakes west and east of the Bhutan suggest that a great earthquake may have ruptured a 700 to 800 km long section of the MFT during a single event around AD 1100. However, between 89°E and 92°E where the MFT runs along the southern border of the Kingdom of Bhutan, no major earthquakes has been recorded so far. In December 2012, we carried out a morphotectonic and paleosismologic study within two sites along the MFT in central Bhutan. We identified several sequences of abandoned fluvial terraces that have been uplifted along the fault. From a kinematic GPS survey, we estimated that the oldest terrace sequence (T2) displays a cumulative offset of ~60 m. A younger sequence (T1) showed an offset of ~4 m on the lower terrace (T1a) and ~9 m on the upper one (T1b). We interpret this 4 m uplift as the vertical component of the last seismic event while the 9 m may be the cumulative offset of the two last earthquakes. These preliminary observations may suggest that the latest seismic event as well as the penultimate event correspond to two major M>8 events. Samples for 14C, OSL and 10Be dating (charcoals, fine sands and quartz rich cobbles, respectively) have been collected in excavations within the different uplifted alluvial surfaces in order to determine the ages of these two last seismic events as well as the Holocene uplift and shortening rates. Compiled with the morphotectonic and paleoseismological data published in the literature, these new results will allow discussing the

  14. Long-Term Slip Rate on the Southern San Andreas Fault Determined by Th-230/U Dating of Pedogenic Carbonate.

    Science.gov (United States)

    Fletcher, K. E.; Johnson, G.; Kendrick, K. J.; Hudnut, K. W.; Sharp, W. D.

    2006-12-01

    Determinations of long-term slip rates are limited, in part, by our ability to accurately estimate the age of offset landforms. U-series dating on pedogenic carbonate provides a relatively novel way of dating landforms, with strengths that complement more widely applied cosmogenic (CRN) techniques. We present new Th-230/U dates for pedogenic carbonate coatings on pebbles of the Biskra Palms fan, near Indio, California, which is offset by the southern San Andreas fault. Small, carefully chosen samples of dense pedogenic carbonate analyzed by mass spectrometry, have 3-10 ppm uranium and low common thorium (Th-232), making them highly favorable for U-series dating. Only minor corrections for initial Th-230 are necessary, and are made using Th-232 as an index isotope with propagation of uncertainties. Samples of early-formed carbonate collected from depths of about 2 m in fan soils typically consist of dense coatings 200-500 microns thick. Such coatings from 6 pebbles from 3 different locations within the fan yield apparent ages between 30 ± 2 ka and 46 ± 2 ka (all errors 2 sigma), with a median age of 38.4 ka (n= 11). Each age averages over the sampled interval of coating growth, hence the spread of ages reflects clast-to-clast variation in coating accumulation rates. All ages are therefore minimum ages for the stabilization of the fan because the time lag between stabilization and carbonate pedogenesis at Biskra Palms is, as yet, unknown. Sub-samples of individual clast-coatings yield ages in good agreement-- e.g., 45.0 ± 0.8 ka, 46.0 ± 1.8 ka, 44.8 ± 1.0 ka, 45.7 ± 0.9 ka (MSWD = 0.88), demonstrating closed U-Th systems. Van der Woerd et al (2006) reported an average CRN age of 35.5 ± 2.5 ka for the fan surface and an offset of 565 ± 80 m, for a slip rate of 15.9 ± 3.4 mm/a. Using their offset, and our oldest mean age of 45.3 ± 0.5 Ma (n=4, ages above) as the minimum landform age, we estimate a maximum slip rate of 12.5 ± 1.8 mm/a. This maximum average

  15. Slip rates and spatially variable creep on faults of the northern San Andreas system inferred through Bayesian inversion of Global Positioning System data

    Science.gov (United States)

    Murray, Jessica R.; Minson, Sarah E.; Svarc, Jerry L.

    2014-01-01

    Fault creep, depending on its rate and spatial extent, is thought to reduce earthquake hazard by releasing tectonic strain aseismically. We use Bayesian inversion and a newly expanded GPS data set to infer the deep slip rates below assigned locking depths on the San Andreas, Maacama, and Bartlett Springs Faults of Northern California and, for the latter two, the spatially variable interseismic creep rate above the locking depth. We estimate deep slip rates of 21.5 ± 0.5, 13.1 ± 0.8, and 7.5 ± 0.7 mm/yr below 16 km, 9 km, and 13 km on the San Andreas, Maacama, and Bartlett Springs Faults, respectively. We infer that on average the Bartlett Springs fault creeps from the Earth's surface to 13 km depth, and below 5 km the creep rate approaches the deep slip rate. This implies that microseismicity may extend below the locking depth; however, we cannot rule out the presence of locked patches in the seismogenic zone that could generate moderate earthquakes. Our estimated Maacama creep rate, while comparable to the inferred deep slip rate at the Earth's surface, decreases with depth, implying a slip deficit exists. The Maacama deep slip rate estimate, 13.1 mm/yr, exceeds long-term geologic slip rate estimates, perhaps due to distributed off-fault strain or the presence of multiple active fault strands. While our creep rate estimates are relatively insensitive to choice of model locking depth, insufficient independent information regarding locking depths is a source of epistemic uncertainty that impacts deep slip rate estimates.

  16. Faulted terrace risers place new constraints on the late Quaternary slip rate for the central Altyn Tagh fault, northwest Tibet

    Science.gov (United States)

    Gold, R.D.; Cowgill, E.; Arrowsmith, J.R.; Chen, X.; Sharp, W.D.; Cooper, K.M.; Wang, X.-F.

    2011-01-01

    The active, left-lateral Altyn Tagh fault defines the northwestern margin of the Tibetan Plateau in western China. To clarify late Quaternary temporal and spatial variations in slip rate along the central portion of this fault system (85??-90??E), we have more than doubled the number of dated offset markers along the central Altyn Tagh fault. In particular, we determined offset-age relations for seven left-laterally faulted terrace risers at three sites (Kelutelage, Yukuang, and Keke Qiapu) spanning a 140-km-long fault reach by integrating surficial geologic mapping, topographic surveys (total station and tripod-light detection and ranging [T-LiDAR]), and geochronology (radiocarbon dating of organic samples, 230Th/U dating of pedogenic carbonate coatings on buried clasts, and terrestrial cosmogenic radionuclide exposure age dating applied to quartz-rich gravels). At Kelutelage, which is the westernmost site (37.72??N, 86.67??E), two faulted terrace risers are offset 58 ?? 3 m and 48 ?? 4 m, and formed at 6.2-6.1 ka and 5.9-3.7 ka, respectively. At the Yukuang site (38.00??N, 87.87??E), four faulted terrace risers are offset 92 ?? 12 m, 68 ?? 6 m, 55 ?? 13 m, and 59 ?? 9 m and formed at 24.2-9.5 ka, 6.4-5.0 ka, 5.1-3.9 ka, and 24.2-6.4 ka, respectively. At the easternmost site, Keke Qiapu (38.08??N, 88.12??E), a faulted terrace riser is offset 33 ?? 6 m and has an age of 17.1-2.2 ka. The displacement-age relationships derived from these markers can be satisfied by an approximately uniform slip rate of 8-12 mm/yr. However, additional analysis is required to test how much temporal variability in slip rate is permitted by this data set. ?? 2011 Geological Society of America.

  17. Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela

    Science.gov (United States)

    Pousse-Beltran, Lea; Vassallo, Riccardo; Audemard, Franck; Jouanne, François; Carcaillet, Julien; Pathier, Erwan; Volat, Matthieu

    2017-07-01

    The Boconó fault is a strike-slip fault lying between the North Andean Block and the South American plate which has triggered at least five Mw > 7 historical earthquakes in Venezuela. The North Andean Block is currently moving toward NNE with respect to a stable South American plate. This relative displacement at 12 mm yr-1 in Venezuela (within the Maracaibo Block) was measured by geodesy, but until now the distribution and rates of Quaternary deformation have remained partially unclear. We used two alluvial fans offset by the Boconó fault (Yaracuy Valley) to quantify slip rates, by combining 10Be cosmogenic dating with measurements of tectonic displacements on high-resolution satellite images (Pleiades). Based upon a fan dated at >79 ka and offset by 1350-1580 m and a second fan dated at 120-273 ka and offset by 1236-1500 m, we obtained two Pleistocene rates of 5.0-11.2 and <20.0 mm yr-1, consistent with the regional geodesy. This indicates that the Boconó fault in the Yaracuy Valley accommodates 40 to 100% of the deformation between the South American plate and the Maracaibo Block. As no aseismic deformation was shown by interferometric synthetic aperture radar analysis, we assume that the fault is locked since the 1812 event. This implies that there is a slip deficit in the Yaracuy Valley since the last earthquake ranging from 1 to 4 m, corresponding to a Mw 7-7.6 earthquake. This magnitude is comparable to the 1812 earthquake and to other historical events along the Boconó fault.

  18. Auto-Optimization of Dewetting Rates by Rim Instabilities in Slipping Polymer Films

    Science.gov (United States)

    Reiter, Günter; Sharma, Ashutosh

    2001-10-01

    We investigated the instability of the moving rim in dewetting of slipping polymer films. Small fluctuations of the width of the rim get spontaneously amplified since narrower sections of the rim move faster than wider ones due to frictional forces being proportional to the width of the rim. Instability leads eventually to an autocontrol of the rim width by the continuous formation of droplets with a mean size proportional to the initial film thickness. Surprisingly, the mean dewetting velocity at late stages, averaged over the length of the rim, was found to be constant. Thus, the instability of the rim enabled a more efficient, i.e., faster, ``drying'' of the substrate. Nonslipping films did not show this instability.

  19. Continuity of slip rates over various time scales on the Puente Hills Blind-thrust Fault, Los Angeles, California

    Science.gov (United States)

    Bergen, Kristian J.; Shaw, John H.; Leon, Lorraine A.; Dolan, James F.; Pratt, Thomas L.; Ponti, Daniel J.; Barrera, Wendy; Rhodes, Edward J.; Murari, Madhav K.; Owen, Lewis A.

    2014-05-01

    Our study seeks to assess the history of slip on the Los Angeles segment of the Puente Hills blind-thrust fault system (PHT) from its inception through the Holocene by integrating a suite of geological and geophysical datasets. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. It is also well suited to slip rate studies, as fold scarps formed by slip on the PHT at depth have been continually buried by flood deposits from the Los Angeles and San Gabriel Rivers, preserving a record of uplift in the form of growth stratigraphy. We determined uplift from the growth stratigraphy by measuring the difference in sediment thickness across the folded layers. At our study site above the western segment of the PHT, the fold structure was imaged by industry seismic reflection data and a pair of high-resolution (100 to 700 m depth) seismic reflection profiles acquired by the authors for this study using weight drop and small vibrator sources. The industry and high-resolution profiles were stacked, migrated and depth converted using a velocity model based on the stacking velocities and the Southern California Earthquake Center Community Velocity Model. The shallowest layers of growth stratigraphy were geometrically constrained by lithological correlations across a series of cone penetration tests and continuously cored boreholes. Age control was provided by radiocarbon dating, optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) dating, and sequence-stratigraphic boundaries. Radiocarbon dating was used to constrain individual earthquake event ages in the borehole transect. Using a novel coring procedure, light-protected samples for quartz OSL and feldspar IRSL dating were acquired from a 171-m-deep borehole that we drilled within the growth fold. These samples provided age constraints on growth strata that were tied to prominent seismic reflections and were combined with

  20. Late Quaternary slip rates of two active thrust faults at the front of the Andean Precordillera, Mendoza, Argentina

    Science.gov (United States)

    Hetzel, R.; Schmidt, S.; Ramos, V. A.; Mingorance, F.

    2010-12-01

    Several destructive earthquakes occurred in the last several hundred years along the active mountain front of the Andean Precordillera between 30°S and 33°S (Siame et al., 2002). However, slip rates of active reverse faults remain largely unknown and the seismic hazard related to these faults is still poorly constrained. Here we report slip rates for two active thrusts located north of Mendoza, the Penas and Cal thrusts, which offset Late Pleistocene to Holocene terraces and form well preserved fault scarps. At the Penas thrust three terraces (T1, T2 and T3) are displaced vertically by 0.9, 2 and 11 m, respectively. 10Be and 14C age constraints yield a vertical slip rate of ~0.9 mm/a for the Penas thrust fault. Combined with the dip angle of the fault of ~25°, this leads to a horizontal shortening rate of about 2 mm/a. At the Cal thrust the highest terrace, which has a maximum 10Be age of 12 ka, is displaced by ~7.5 m. This translates into a minimum horizontal shortening rate of about 1 mm/a. Comparison with short-term GPS data (Brooks et al., 2003) suggests that both the Penas and Cal thrusts accomodate a significant portion of the present-day E-W shortening rate in the eastern Andes. The vertical surface displacements derived from the smallest scarps is 0.9 m for both thrusts. Hence, given their length (Penas thrust: 40 km, Cal thrust: 31 km), these faults are capable of producing magnitude 7 earthquakes (Wells & Coppersmith, 1994), which is confirmed by a Ms = 7.0 earthquake on the Cal thrust that destroyed the city of Mendoza in 1861. Assuming characteristic earthquakes for both faults suggests average reccurence intervals of 1000 to 1500 years during the Holocene. References Brooks, B.A., Bevis, M., Smalley, R., Kendrick, E., Manceda, R., Lauria, E., Maturana, R., Araujo, M., 2003. Crustal motion in the Southern Andes (26°-36°S): Do the Andes behave like a microplate? Geochemistry Geophysics Geosystems 4, doi: 10.1029/2003GC000505. Siame, L.L., Bellier, O

  1. Long-term slip rate of the southern San Andreas Fault, from 10Be-26Al surface exposure dating of an offset alluvial fan

    Energy Technology Data Exchange (ETDEWEB)

    der Woerd, J v; Klinger, Y; Sieh, K; Tapponnier, P; Ryerson, F; M?riaux, A

    2006-01-13

    We determine the long-term slip rate of the southern San Andreas Fault in the southeastern Indio Hills using {sup 10}Be and {sup 26}Al isotopes to date an offset alluvial fan surface. Field mapping complemented with topographic data, air photos and satellite images allow to precisely determine piercing points across the fault zone that are used to measure an offset of 565 {+-} 80 m. A total of twenty-six quartz-rich cobbles from three different fan surfaces were collected and dated. The tight cluster of nuclide concentrations from 19 samples out of 20 from the offset fan surface implies a simple exposure history, negligible prior exposure and erosion, and yield an age of 35.5 {+-} 2.5 ka. The long-term slip rate of the San Andreas Fault south of Biskra Palms is thus 15.9 {+-} 3.4 mm/yr. This rate is about 10 mm/yr slower than geological (0-14 ka) and short-term geodetic estimates for this part of the San Andreas Fault implying changes in slip rate or in faulting behavior. This result puts new constraints on the slip rate of the San Jacinto and on the Eastern California Shear Zone for the last 35 ka. Our study shows that more sites along the major faults of southern California need to be targeted to better constrain the slip-rates over different time scales.

  2. Lidar and Luminescence Dating Analysis of Latest Pleistocene-Holocene Slip Rates on the Awatere fault at Saxton River, South Island, New Zealand

    Science.gov (United States)

    Zinke, R. W.; Dolan, J. F.; Van Dissen, R. J.; McGuire, C. P.; Rhodes, E. J.; Hatem, A. E.; Grenader, J.; Langridge, R.

    2015-12-01

    We use high-resolution lidar imagery and luminescence dating to constrain incremental Holocene-late Pleistocene slip rates at the well-known Saxton River site along the Awatere fault, which is a primary fault in the Marlborough Fault System, South Island, New Zealand. Previous studies examining the ages and displacements of offset fluvial terraces and bedrock features at the Saxton River site suggest that slip rates along the Awatere fault have been highly variable since ~16 ka, exhibiting rates as low as ~3 mm/yr and as fast ~13 mm/yr, with an average of ~6 mm/yr (e.g., Mason et al., 2006). Mapping on high-resolution lidar topographic data and additional field surveys yield revised measurements of the five fluvial terrace risers and bedrock ridge that have been offset by the Awatere fault at the Saxton River site. Improved dating of those geomorphic features provided by post-IR50-IRSL225 luminescence ages allows us to more accurately constrain the incremental slip rates recorded at this site. Preliminary results suggest that the slip rate during latest Pleistocene-Holocene time has indeed varied considerably over millennial timescales. This study is part of a broader effort aimed at determining incremental slip rates and paleo-earthquake ages and displacements from all four main Marlborough faults. Collectively, these data will allow us to determine how the Marlborough system faults have worked together during the Holocene-late Pleistocene to accommodate plate-boundary deformation in time and space.

  3. Optimizing kick rate and amplitude for Paralympic swimmers via net force measures.

    Science.gov (United States)

    Fulton, Sacha K; Pyne, David; Burkett, Brendan

    2011-02-01

    Kicking is a key component of freestyle swimming yet the optimum combination of kick rate and kick amplitude remains unknown. For Paralympic swimmers, with upper and lower limb disabilities, the influence of the kick plays an important role in net force production. To determine optimum kick characteristics, 12 Paralympic swimmers aged 19.8 ± 2.9 years (mean ± s) were towed at their individual peak freestyle speed. The experimental conditions were (i) a prone streamline glide for passive trials and (ii) maximal freestyle kicking in a prone streamline for active trials at different speeds and kick amplitudes. Kick rate was quantified using inertial sensor technology. Towing speed was assessed using a novel and validated dynamometer, and net force was assessed using a Kistler force-platform system. When peak speed was increased by 5%, the active force increased 24.2 ± 5.3% (90% confidence limits), while kick rate remained at approximately 150 kicks per minute. Larger amplitude kicking increased the net active force by 25.1 ± 10.6%, although kick rate decreased substantially by 13.6 ± 5.1%. Based on the current kick rate and amplitude profile adopted by Paralympic swimmers, these characteristics are appropriate for optimizing net force.

  4. Single interval longwave radiation scheme based on the net exchanged rate decomposition with bracketing

    Czech Academy of Sciences Publication Activity Database

    Geleyn, J.- F.; Mašek, Jan; Brožková, Radmila; Kuma, P.; Degrauwe, D.; Hello, G.; Pristov, N.

    2017-01-01

    Roč. 143, č. 704 (2017), s. 1313-1335 ISSN 0035-9009 R&D Projects: GA MŠk(CZ) LO1415 Keywords : numerical weather prediction * climate models * clouds * parameterization * atmospheres * formulation * absorption * scattering * accurate * database * longwave radiative transfer * broadband approach * idealized optical paths * net exchanged rate decomposition * bracketing * selective intermittency Impact factor: 3.444, year: 2016

  5. Spatial variation in tuber depletion by swans explained by differences in net intake rates

    NARCIS (Netherlands)

    Nolet, BA; Langevoord, O; Bevan, RM; Engelaar, KR; Klaassen, M; Mulder, RJW

    We tested whether the spatial variation in resource depletion by Tundra Swans (Cygnus columbianus) foraging on belowground tubers of sage pondweed (Potnmogeton pectinatus) was caused by differences in net energy intake rates. The variation in giving up densities within the confines of one lake was

  6. Spatial variation in tuber depletion by swans explained by differences in net intake rates

    NARCIS (Netherlands)

    Nolet, B.A.; Langevoord, O.; Bevan, R.M.; Engelaar, K.R.; Klaassen, M.R.J.; Mulder, R.J.W.; Van Dijk, S.

    2001-01-01

    We tested whether the spatial variation in resource depletion by Tundra Swans (Cygnus columbianus) foraging on belowground tubers of sage pondweed (Potnmogeton pectinatus) was caused by differences in net energy intake rates. The variation in giving up densities within the confines of one lake was

  7. Late Holocene Paleoseismic Timing and Slip Rate Along The Missyaf Segment of The Dead Sea Fault In Syria

    Science.gov (United States)

    Meghraoui, M.; Gomez, F.; Sbeinati, R.; van der Woerd, J.; Mouty, M.; Darkal, A.; Darawcheh, R.; Radwan, Y.; Al-Ghazzi, R.; Barazangi, M.

    We investigate the timing of Holocene earthquakes and related slip rate along the main segment of the Dead Sea fault south of the Ghab pull-apart basin in western Syria. The 60-70 km long Missyaf segment consists of a single fault branch of the north-south trending left-lateral fault at the plate boundary between Africa and Arabia. The late Quaternary tectonic activity along the fault is characterized by (1) deflected streams with consistent left-lateral displacements of different sizes (50 to 300 m), and (2) ev- idence of large shutter-ridge structures and small pull-apart basins. Microtopographic surveys and trenching across the fault at two sites document the size and timing of paleoseismic events and the related faulting behaviour. Near El Harif village, the fault cut across a Roman aqueduct (younger than 22 AD) and induces 13.6 s0.1 m of left-´ lateral displacement. Nearby trench-excavations and test pits exhibit the fault with the shear zone affecting a succession of young alluvial deposits of a terrace meander. First radiocarbon dating of the faulting events with vertical displacements reveal the occur- rence of a large seismic event prior to 348 BC - 810 BC, a penultimate event between 650 - 1152 AD and the most recent event between 979 - 1255 AD. The two most re- cent events being most likely responsible for the Roman aqueduct total displacement, it implies a coseismic left-lateral movement of 6.8 m per event at this location and a slip rate of about 6 - 7 mm/yr for the last 2000 years. The correlation with the histor- ical seismicity catalogue suggests that the most recent faulting event may correspond to the well documented large earthquake of 1170 AD for which we estimate Mw = 7.3 - 7.5.

  8. Active faulting within a megacity: the geometry and slip rate of the Pardisan thrust in central Tehran, Iran

    Science.gov (United States)

    Talebian, M.; Copley, A. C.; Fattahi, M.; Ghorashi, M.; Jackson, J. A.; Nazari, H.; Sloan, R. A.; Walker, R. T.

    2016-12-01

    Tehran, the capital city of Iran with a population of over 12 million, is one of the largest urban centres within the seismically active Alpine-Himalayan orogenic belt. Although several historic earthquakes have affected Tehran, their relation to individual faults is ambiguous for most. This ambiguity is partly due to a lack of knowledge about the locations, geometries and seismic potential of structures that have been obscured by dramatic urban growth over the past three decades, and which have covered most of the young geomorphic markers and natural exposures. Here we use aerial photographs from 1956, combined with an ˜1 m DEM derived from stereo Pleiades satellite imagery to investigate the geomorphology of a growing anticline above a thrust fault-the Pardisan thrust-within central Tehran. The topography across the ridge is consistent with a steep ramp extending from close to the surface to a depth of ˜2 km, where it presumably connects with a shallow-dipping detachment. No primary fault is visible at the surface, and it is possible that the faulting dissipates in the near surface as distributed shearing. We use optically stimulated luminescence to date remnants of uplifted and warped alluvial deposits that are offset vertically across the Pardisan fault, providing minimum uplift and slip-rates of at least 1 mm yr-1. Our study shows that the faults within the Tehran urban region have relatively rapid rates of slip, are important in the regional tectonics, and have a great impact on earthquake hazard assessment of the city and surrounding region.

  9. Net capital flows to and the real exchange rate of Western Balkan countries

    Directory of Open Access Journals (Sweden)

    Gabrisch Hubert

    2015-01-01

    Full Text Available This paper uses Granger causality tests to assess the linkages between changes in the real exchange rate and net capital inflows using the example of Western Balkan countries, which have suffered from low competitiveness and external imbalances for many years. The real exchange rate is a measure of a country’s price competitiveness, and the paper uses two concepts: relative unit labour cost and relative inflation differential. The sample consists of six Western Balkan countries for the period 1996-2012, relative to the European Union (EU. The main finding is that changes in the net capital flows precede changes in relative unit labour costs and not vice versa. Also, there is evidence that net capital flows affect the inflation differential of countries, although to a less discernible extent. This suggests that the increasing divergence in the unit labour cost between the EU and Western Balkan countries up to the global financial crisis was at least partly the result of net capital inflows. The paper adds to the ongoing debate on improving cost competitiveness through wage restrictions as the main vehicle to avert the accumulation of current account imbalances. It shows the importance of changes in the exchange rate regime, reform of the interaction between the financial and the real sector, and financial supervision and structural change.

  10. Fault Coupling, Slip Rate Deficit and Strain Accumulation of the Haiyuan-Liupanshan Fault Zone in the Northeastern Margin of the Tibetan Plateau

    Science.gov (United States)

    Li, Y.; Shan, X.; Qu, C.; Song, X.; Jiang, Y.; Gong, W.; Zhang, G.; Zhang, Y.

    2016-12-01

    The Haiyuan-Liupanshan fault is one of the main left-lateral fault system in the northeastern edge of the Tibetan Plateau, which contributes to the rising and eastward extrusion of lithospheric blocks. It is a particularly well-suited area to understand the mechanisms of deformation which led to the growth and rise of the Tibet. Besides, the unbroken section (the Tianzhu seismic gap), which was bracketed by two M8 earthquakes (1920 and 1927), was interpreted with high seismic potential. Based on the GPS and geology (slip rate and fault slip vector azimuth) data, we invert for the fault coupling, the slip rate deficit and the strain rate accumulation along the Haiyuan-Liupanshan fault. It's of great importance for a better understanding of interseismic deformation, strain loading and seismic potential assessment. Along the Haiyuan fault, the results show 3.2-6.2 mm/yr of left-lateral strike-slip, and the strike-slip transformed into thrusting deformation (2.8-3.5 mm/yr) along the Liupanshan fault. The results suggest full coupling down to 10 km along the Haiyuan fault. Significant portions from the Jinqianghe fault to the Maomaoshan fault, however, are locked to 23 km depth. The abrupt change in fault coupling coincides with the Tianzhu seismic gap. High slip rate deficit (3.0-4.5 mm/yr) and seismic moment accumulation rate are also interpreted along the seismic gap. The Liupanshan fault is locked to 15-20 km depth. A high seismic moment accumulation rate but low slip rate deficit (2.0-3.2 mm/yr) are inverted along the fault. The fault locking depth is negatively correlated with the coulomb stress accumulation rate and the second invariant of the strain rate tensor. That is, low strain accumulation rates are inverted along the seismic gap and the Liupanshan fault. A possible explanation is that the total amount of the elastic strain along the fault may have reached a high level, but with a low accumulation rate. High seismic hazard are interpreted considering the

  11. Light environment alters ozone uptake per net photosynthetic rate in black cherry trees.

    Science.gov (United States)

    Fredericksen, T S; Kolb, T E; Skelly, J M; Steiner, K C; Joyce, B J; Savage, J E

    1996-05-01

    Foliar ozone uptake rates of different-sized black cherry (Prunus serotina Ehrh.) trees were compared within a deciduous forest and adjacent openings in north-central Pennsylvania during one growing season. Study trees included open-grown seedlings and saplings, forest understory seedlings and saplings, and sunlit and shaded portions of mature canopy tree crowns. Instantaneous ozone uptake rates were highest in high-light environments primarily because of higher stomatal conductances. Low ozone uptake rates of seedlings and saplings in the forest understory could be attributed partially to lower average ambient ozone concentrations compared to the canopy and open environments. Among the tree size and light combinations tested, ozone uptake rates were highest in open-grown seedlings and lowest in forest-grown seedlings. Despite lower ozone uptake rates of foliage in shaded environments, ozone uptake per net photosynthesis of foliage in shaded environments was significantly higher than that of foliage in sunlit environments because of weaker coupling between net photosynthesis and stomatal conductance in shaded environments. The potential for greater ozone injury in shaded environments as a result of greater ozone uptake per net photosynthesis is consistent with previous reports of greater ozone injury in shaded foliage than in sunlit foliage.

  12. Paleoseismology and slip rate of the Conway Segment of the Hope Faultat Greenburn Stream, South Island, New Zealand

    Directory of Open Access Journals (Sweden)

    B. Estrada

    2003-06-01

    maximum duration of time in which the last 2 earthquake events occurred to be 545 years (1295-1840 A.D.. This is consistent with the average Recurrence Interval (RI of 180-310 years that we determine using two independent paths. The soil record indicates that each event is separated by a significant period of time, comparable to the calculated RI. The most recent event is constrained between ca. 1780 A.D. ± 60 years, taking into account the dates from these trenches, a weathering rind age, and from stratigraphic correlation at the site. Event III probably occurred before 1220 A.D. A maximum dextral slip rate of 23 ± 4 mm/yr is calculated from the minimum fan age and the offset/deflection of a stream channel along the shutter ridge. In concert with the estimate of single event displacement (5-6 m, these results show that the Conway Segment of the Hope Fault is fast-slipping and has ruptured regularly as a result of large earthquakes prior to the European colonisation of New Zealand.

  13. [Determination of linear sintering shrinkage rate of slip-casting infiltrated ceramic].

    Science.gov (United States)

    Meng, Y; Cao, Y; Liao, Y

    1998-05-01

    This study tested the linear sintering shrinkage (SS) rate of ceramic infiltrated with different glasses (Vita In-ceram, G I-I La, G I-II La, G I-II Ce), the results showed that the linear SS rate was 0.08%-0.32%, which occurred mainly in the firing stage of alumina (P 0.05). It suggests that the effects of glass infiltration on the dimensional stability of GI glasses were comparable with that of Vita In-ceram.

  14. Average slip rate at the transition zone on the plate interface in the Nankai subduction zone, Japan, estimated from short-term SSE catalog

    Science.gov (United States)

    Itaba, S.; Kimura, T.

    2013-12-01

    Short-term slow slip events (S-SSEs) in the Nankai subduction zone, Japan, have been monitored by borehole strainmeters and borehole accelerometers (tiltmeters) mainly. The scale of the S-SSE in this region is small (Mw5-6), and therefore there were two problems in S-SSE identification and estimation of the fault model. (1) There were few observatories that can detect crustal deformation associated with S-SSEs. Therefore, reliability of the estimated fault model was low. (2) The signal associated with the S-SSE is relatively small. Therefore, it was difficult to detect the S-SSE only from strainmeter and tiltmeter. The former problem has become resolvable to some extent by integrating the data of borehole strainmeter, tiltmeter and groundwater (pore pressure) of the National Institute of Advanced Industrial Science and Technology, tiltmeter of the National Research Institute for Earthquake Science and Disaster Prevention and borehole strainmeter of the Japan Meteorological Agency. For the latter, by using horizontal redundant component of a multi-component strainmeter, which consists generally of four horizontal extensometers, it has become possible to extract tectonic deformation efficiently and detect a S-SSE using only strainmeter data. Using the integrated data and newly developed technique, we started to make a catalog of S-SSE in the Nankai subduction zone. For example, in central Mie Prefecture, we detect and estimate fault model of eight S-SSEs from January 2010 to September 2012. According to our estimates, the average slip rate of S-SSE is 2.7 cm/yr. Ishida et al. [2013] estimated the slip rate as 2.6-3.0 cm/yr from deep low-frequency tremors, and this value is consistent with our estimation. Furthermore, the slip deficit rate in this region evaluated by the analysis of GPS data from 2001 to 2004 is 1.0 - 2.6 cm/yr [Kobayashi et al., 2006], and the convergence rate of the Philippine Sea plate in this region is estimated as 5.0 - 7.0 cm/yr. The difference

  15. Holocene slip rates along the San Andreas Fault System in the San Gorgonio Pass and implications for large earthquakes in southern California

    Science.gov (United States)

    Heermance, Richard V.; Yule, Doug

    2017-06-01

    The San Gorgonio Pass (SGP) in southern California contains a 40 km long region of structural complexity where the San Andreas Fault (SAF) bifurcates into a series of oblique-slip faults with unknown slip history. We combine new 10Be exposure ages (Qt4: 8600 (+2100, -2200) and Qt3: 5700 (+1400, -1900) years B.P.) and a radiocarbon age (1260 ± 60 years B.P.) from late Holocene terraces with scarp displacement of these surfaces to document a Holocene slip rate of 5.7 (+2.7, -1.5) mm/yr combined across two faults. Our preferred slip rate is 37-49% of the average slip rates along the SAF outside the SGP (i.e., Coachella Valley and San Bernardino sections) and implies that strain is transferred off the SAF in this area. Earthquakes here most likely occur in very large, throughgoing SAF events at a lower recurrence than elsewhere on the SAF, so that only approximately one third of SAF ruptures penetrate or originate in the pass.Plain Language SummaryHow large are earthquakes on the southern San Andreas Fault? The answer to this question depends on whether or not the earthquake is contained only along individual fault sections, such as the Coachella Valley section north of Palm Springs, or the rupture crosses multiple sections including the area through the San Gorgonio Pass. We have determined the age and offset of faulted stream deposits within the San Gorgonio Pass to document slip rates of these faults over the last 10,000 years. Our results indicate a long-term slip rate of 6 mm/yr, which is almost 1/2 of the rates east and west of this area. These new rates, combined with faulted geomorphic surfaces, imply that large magnitude earthquakes must occasionally rupture a 300 km length of the San Andreas Fault from the Salton Sea to the Mojave Desert. Although many ( 65%) earthquakes along the southern San Andreas Fault likely do not rupture through the pass, our new results suggest that large >Mw 7.5 earthquakes are possible on the southern San Andreas Fault and likely

  16. Relationship Between Diurnal Changes of Net Photosynthetic Rate and Influencing Factors in Rice under Saline Sodic Stress

    Directory of Open Access Journals (Sweden)

    Fu Yang

    2008-06-01

    Full Text Available The net photosynthetic rate of flag leaves and influencing factors under saline sodic soil conditions were investigated at the full heading stage of rice. The net photosynthetic rate of rice leaves showed a double-peak curve in a day in both non-saline sodic and saline sodic soil treatments. The first peak of the net photosynthetic rate appeared at 9:00–10:00 and 9:00 in the saline sodic and non-saline sodic soil treatments, respectively, whereas the second peak both at 14:00. The midday depression of the net photosynthetic rate always appeared regardless of non-saline sodic or saline sodic soil conditions. In addition, the net photosynthetic rate significantly decreased in all day under saline sodic conditions compared with that under non-saline sodic conditions. Some differences were observed in correlation characters between the net photosynthetic rate and all influencing factors during 9:00–13:00. Under non-saline sodic conditions, the diurnal changes of the net photosynthetic rate in a day were mainly caused by stomatal conductance, and the limitation value and the stomatal factors served as determinants; whereas under saline sodic stress, the diurnal changes of the net photosynthetic rate in a day were mainly caused by non stomatal factors including light intensity and air temperature.

  17. Updated Long Term Fault Slip Rates and Seismic Hazard in the Central Alborz, Iran: New Constraints From InSAR and GPS

    Science.gov (United States)

    Weston, J. M.; Shirzaei, M.

    2015-12-01

    The Alborz mountain range, located south of the Caspian Sea, accommodates 30% of the 25 mm/yr convergence between Arabia and Eurasia. The resulting shortening and left lateral motion is distributed over several active fault zones within the Central Alborz. Despite earlier efforts using only GPS data, little is known about the long term rate of vertical deformation and aseismic slip. Several historical earthquakes have affected this region, some of the largest of these events occurred on the Mosha fault which is close to the capital city, Tehran, which has a population of over eight million. Thus, constraining the interseismic slip rates in this region is particularly important. In this study we complement existing horizontal velocities from a regional GPS network, with line of sight velocities from interferometric synthetic aperture radar (InSAR), to provide additional constraints on the vertical deformation and enhance the spatial coverage. Assuming a seismogenic depth of 30 km, based on microseismicity data, we solve for the geometry and long term slip rates on four major fault strands in this region. We obtain a long term slip rate of ~ 3 mm/yr for the Mosha and North Alborz faults, and ~ 10 mm/yr for the Khazar fault and Parchin faults. These rates and fault geometries are in agreement with earlier works, and fit the GPS data well. However, close to the fault traces there are large residuals in the InSAR data, suggesting that there is shallow creep (Khazar faults are creeping. This new observation of fault creep has direct implications for the seismic hazard in the region. On the Mosha fault we estimate a slip deficit equivalent to a Mw 7.0 event. The combination of InSAR and GPS provide vital information for assessing the interseismic deformation in the Central Alborz, and these results highlight the importance of closer monitoring of this region to better understand the seismic hazard.

  18. Analysis of a Dynamic Viscoelastic Contact Problem with Normal Compliance, Normal Damped Response, and Nonmonotone Slip Rate Dependent Friction

    Directory of Open Access Journals (Sweden)

    Mikaël Barboteu

    2016-01-01

    Full Text Available We consider a mathematical model which describes the dynamic evolution of a viscoelastic body in frictional contact with an obstacle. The contact is modelled with a combination of a normal compliance and a normal damped response law associated with a slip rate-dependent version of Coulomb’s law of dry friction. We derive a variational formulation and an existence and uniqueness result of the weak solution of the problem is presented. Next, we introduce a fully discrete approximation of the variational problem based on a finite element method and on an implicit time integration scheme. We study this fully discrete approximation schemes and bound the errors of the approximate solutions. Under regularity assumptions imposed on the exact solution, optimal order error estimates are derived for the fully discrete solution. Finally, after recalling the solution of the frictional contact problem, some numerical simulations are provided in order to illustrate both the behavior of the solution related to the frictional contact conditions and the theoretical error estimate result.

  19. Baseline Assessment of Net Calcium Carbonate Accretion Rates on U.S. Pacific Reefs.

    Directory of Open Access Journals (Sweden)

    Bernardo Vargas-Ángel

    Full Text Available This paper presents a comprehensive quantitative baseline assessment of in situ net calcium carbonate accretion rates (g CaCO3 cm(-2 yr(-1 of early successional recruitment communities on Calcification Accretion Unit (CAU plates deployed on coral reefs at 78 discrete sites, across 11 islands in the central and south Pacific Oceans. Accretion rates varied substantially within and between islands, reef zones, levels of wave exposure, and island geomorphology. For forereef sites, mean accretion rates were the highest at Rose Atoll, Jarvis, and Swains Islands, and the lowest at Johnston Atoll and Tutuila. A comparison between reef zones showed higher accretion rates on forereefs compared to lagoon sites; mean accretion rates were also higher on windward than leeward sites but only for a subset of islands. High levels of spatial variability in net carbonate accretion rates reported herein draw attention to the heterogeneity of the community assemblages. Percent cover of key early successional taxa on CAU plates did not reflect that of the mature communities present on surrounding benthos, possibly due to the short deployment period (2 years of the experimental units. Yet, net CaCO3 accretion rates were positively correlated with crustose coralline algae (CCA percent cover on the surrounding benthos and on the CAU plates, which on average represented >70% of the accreted material. For foreeefs and lagoon sites combined CaCO3 accretion rates were statistically correlated with total alkalinity and Chlorophyll-a; a GAM analysis indicated that SiOH and Halimeda were the best predictor variables of accretion rates on lagoon sites, and total alkalinity and Chlorophyll-a for forereef sites, demonstrating the utility of CAUs as a tool to monitor changes in reef accretion rates as they relate to ocean acidification. This study underscores the pivotal role CCA play as a key benthic component and supporting actively calcifying reefs; high Mg-calcite exoskeletons

  20. Baseline Assessment of Net Calcium Carbonate Accretion Rates on U.S. Pacific Reefs.

    Science.gov (United States)

    Vargas-Ángel, Bernardo; Richards, Cristi L; Vroom, Peter S; Price, Nichole N; Schils, Tom; Young, Charles W; Smith, Jennifer; Johnson, Maggie D; Brainard, Russell E

    2015-01-01

    This paper presents a comprehensive quantitative baseline assessment of in situ net calcium carbonate accretion rates (g CaCO3 cm(-2) yr(-1)) of early successional recruitment communities on Calcification Accretion Unit (CAU) plates deployed on coral reefs at 78 discrete sites, across 11 islands in the central and south Pacific Oceans. Accretion rates varied substantially within and between islands, reef zones, levels of wave exposure, and island geomorphology. For forereef sites, mean accretion rates were the highest at Rose Atoll, Jarvis, and Swains Islands, and the lowest at Johnston Atoll and Tutuila. A comparison between reef zones showed higher accretion rates on forereefs compared to lagoon sites; mean accretion rates were also higher on windward than leeward sites but only for a subset of islands. High levels of spatial variability in net carbonate accretion rates reported herein draw attention to the heterogeneity of the community assemblages. Percent cover of key early successional taxa on CAU plates did not reflect that of the mature communities present on surrounding benthos, possibly due to the short deployment period (2 years) of the experimental units. Yet, net CaCO3 accretion rates were positively correlated with crustose coralline algae (CCA) percent cover on the surrounding benthos and on the CAU plates, which on average represented >70% of the accreted material. For foreeefs and lagoon sites combined CaCO3 accretion rates were statistically correlated with total alkalinity and Chlorophyll-a; a GAM analysis indicated that SiOH and Halimeda were the best predictor variables of accretion rates on lagoon sites, and total alkalinity and Chlorophyll-a for forereef sites, demonstrating the utility of CAUs as a tool to monitor changes in reef accretion rates as they relate to ocean acidification. This study underscores the pivotal role CCA play as a key benthic component and supporting actively calcifying reefs; high Mg-calcite exoskeletons makes CCA

  1. Generation time, net reproductive rate, and growth in stage-age-structured populations

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2014-01-01

    Abstract Major insights into the relationship between life-history features and fitness have come from Lotka's proof that population growth rate is determined by the level (expected amount) of reproduction and the average timing of reproduction of an individual. But this classical result is limited...... to age-structured populations. Here we generalize this result to populations structured by stage and age by providing a new, unique measure of reproductive timing (Tc) that, along with net reproductive rate (R0), has a direct mathematical relationship to and approximates growth rate (r). We use simple...... features of the life history determine population growth rate r and reveal a complex interplay of trait dynamics, timing, and level of reproduction. Our results contribute to a new framework of population and evolutionary dynamics in stage-and-age-structured populations....

  2. Relationship Between Diurnal Changes of Net Photosynthetic Rate and Influencing Factors in Rice under Saline Sodic Stress

    OpenAIRE

    Fu Yang; Zheng-wei Liang; Zhi-chun Wang; Yuan Chen

    2008-01-01

    The net photosynthetic rate of flag leaves and influencing factors under saline sodic soil conditions were investigated at the full heading stage of rice. The net photosynthetic rate of rice leaves showed a double-peak curve in a day in both non-saline sodic and saline sodic soil treatments. The first peak of the net photosynthetic rate appeared at 9:00–10:00 and 9:00 in the saline sodic and non-saline sodic soil treatments, respectively, whereas the second peak both at 14:00. The midday depr...

  3. Late Quaternary eruption of the Ranau Caldera and new geological slip rates of the Sumatran Fault Zone in Southern Sumatra, Indonesia

    Science.gov (United States)

    Natawidjaja, Danny Hilman; Bradley, Kyle; Daryono, Mudrik R.; Aribowo, Sonny; Herrin, Jason

    2017-12-01

    Over the last decade, studies of natural hazards in Sumatra have focused primarily on great earthquakes and associated tsunamis produced by rupture of the Sunda megathrust. However, the Sumatran Fault and the active volcanic arc present proximal hazards to populations on mainland Sumatra. At present, there is little reliable information on the maximum magnitudes and recurrence intervals of Sumatran Fault earthquakes, or the frequency of paroxysmal caldera-forming (VEI 7-8) eruptions. Here, we present new radiocarbon dates of paleosols buried under the voluminous Ranau Tuff that constrain the large caldera-forming eruption to around 33,830-33,450 calender year BP (95% probability). We use the lateral displacement of river channels incised into the Ranau Tuff to constrain the long-term slip rate of two segments of the Sumatran Fault. South of Ranau Lake, the Kumering segment preserves isochronous right-lateral channel offsets of approximately 350 ± 50 m, yielding a minimum slip rate of 10.4 ± 1.5 mm/year for the primary active fault trace. South of Suoh pull-apart depression, the West Semangko segment offsets the Semangko River by 230 ± 60 m, yielding an inferred slip rate of 6.8 ± 1.8 mm/year. Compared with previous studies, these results indicate more recent high-volume volcanism in South Sumatra and increased seismic potency of the southernmost segments of the Sumatran Fault Zone.

  4. Slip rate, magnitudes and ages of surface-rupturing events along the Main Frontal Thrust in Bhutan (Himalaya)

    Science.gov (United States)

    Ritz, J.; Berthet, T.; Ferry, M. A.; Pelgay, P.; Cattin, R.; Drukpa, D.; Braucher, R.; Chophel, J.; Thinley, K.; Hetényi, G.

    2013-12-01

    . After 10Be dating on T2 surface quartz rich cobbles, we estimate a vertical slip rate of 9.3 × 2.6 mm/yr along the MFT in Bhutan.

  5. Low rate loading-induced convection enhances net transport into the intervertebral disc in vivo.

    Science.gov (United States)

    Gullbrand, Sarah E; Peterson, Joshua; Mastropolo, Rosemarie; Roberts, Timothy T; Lawrence, James P; Glennon, Joseph C; DiRisio, Darryl J; Ledet, Eric H

    2015-05-01

    The intervertebral disc primarily relies on trans-endplate diffusion for the uptake of nutrients and the clearance of byproducts. In degenerative discs, diffusion is often diminished by endplate sclerosis and reduced proteoglycan content. Mechanical loading-induced convection has the potential to augment diffusion and enhance net transport into the disc. The ability of convection to augment disc transport is controversial and has not been demonstrated in vivo. To determine if loading-induced convection can enhance small molecule transport into the intervertebral disc in vivo. Net transport was quantified via postcontrast enhanced magnetic resonance imaging (MRI) into the discs of the New Zealand white rabbit lumbar spine subjected to in vivo cyclic low rate loading. Animals were administered the MRI contrast agent gadodiamide intravenously and subjected to in vivo low rate loading (0.5 Hz, 200 N) via a custom external loading apparatus for either 2.5, 5, 10, 15, or 20 minutes. Animals were then euthanized and the lumbar spines imaged using postcontrast enhanced MRI. The T1 constants in the nucleus, annulus, and cartilage endplates were quantified as a measure of gadodiamide transport into the loaded discs compared with the adjacent unloaded discs. Microcomputed tomography was used to quantify subchondral bone density. Low rate loading caused the rapid uptake and clearance of gadodiamide in the nucleus compared with unloaded discs, which exhibited a slower rate of uptake. Relative to unloaded discs, low rate loading caused a maximum increase in transport into the nucleus of 16.8% after 5 minutes of loading. Low rate loading increased the concentration of gadodiamide in the cartilage endplates at each time point compared with unloaded levels. Results from this study indicate that forced convection accelerated small molecule uptake and clearance in the disc induced by low rate mechanical loading. Low rate loading may, therefore, be therapeutic to the disc as it

  6. A New Approach for Mobile Advertising Click-Through Rate Estimation Based on Deep Belief Nets

    Directory of Open Access Journals (Sweden)

    Jie-Hao Chen

    2017-01-01

    Full Text Available In recent years, with the rapid development of mobile Internet and its business applications, mobile advertising Click-Through Rate (CTR estimation has become a hot research direction in the field of computational advertising, which is used to achieve accurate advertisement delivery for the best benefits in the three-side game between media, advertisers, and audiences. Current research on the estimation of CTR mainly uses the methods and models of machine learning, such as linear model or recommendation algorithms. However, most of these methods are insufficient to extract the data features and cannot reflect the nonlinear relationship between different features. In order to solve these problems, we propose a new model based on Deep Belief Nets to predict the CTR of mobile advertising, which combines together the powerful data representation and feature extraction capability of Deep Belief Nets, with the advantage of simplicity of traditional Logistic Regression models. Based on the training dataset with the information of over 40 million mobile advertisements during a period of 10 days, our experiments show that our new model has better estimation accuracy than the classic Logistic Regression (LR model by 5.57% and Support Vector Regression (SVR model by 5.80%.

  7. Biomass rather than growth rate determines variation in net primary production by giant kelp.

    Science.gov (United States)

    Reed, Daniel C; Rassweiler, Andrew; Arkema, Katie K

    2008-09-01

    Net primary production (NPP) is influenced by disturbance-driven fluctuations in foliar standing crop (FSC) and resource-driven fluctuations in rates of recruitment and growth, yet most studies of NPP have focused primarily on factors influencing growth. We quantified NPP, FSC, recruitment, and growth rate for the giant kelp, Macrocystis pyrifera, at three kelp forests in southern California, U.S.A., over a 54-month period and determined the relative roles of FSC, recruitment, and growth rate in contributing to variation in annual NPP. Net primary production averaged between 0.42 and 2.38 kg dry mass x m(-2) x yr(-1) at the three sites. The initial FSC present at the beginning of the growth year and the recruitment of new plants during the year explained 63% and 21% of the interannual variation observed in NPP, respectively. The previous year's NPP and disturbance from waves collectively accounted for 80% of the interannual variation in initial FSC. No correlation was found between annual growth rate (i.e., the amount of new kelp mass produced per unit of existing kelp mass) and annual NPP (i.e., the amount of new kelp mass produced per unit area of ocean bottom), largely because annual growth rate was consistent compared to initial FSC and recruitment, which fluctuated greatly among years and sites. Although growth rate was a poor predictor of variation in annual NPP, it was principally responsible for the high mean values observed for NPP by Macrocystis. These high mean values reflected rapid growth (average of approximately 2% per day) of a relatively small standing crop (maximum annual mean = 444 g dry mass/m2) that replaced itself approximately seven times per year. Disturbance-driven variability in FSC may be generally important in explaining variation in NPP, yet it is rarely examined because cycles of disturbance and recovery occur over timescales of decades or more in many systems. Considerable insight into how variation in FSC drives variation in NPP may

  8. The Palos Verdes Fault offshore Southern California: Late Pleistocene to present tectonic geomorphology, seascape evolution, and slip rate estimate based on AUV and ROV surveys

    Science.gov (United States)

    Brothers, Daniel S.; Conrad, James E.; Maier, Katherine L.; Paull, Charles K.; McGann, Mary; Caress, David W.

    2015-07-01

    The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp subbottom profiles were acquired with an autonomous underwater vehicle (AUV) along the main trace of PVF in water depths between 250 and 600 m. Radiocarbon dates were obtained from vibracores collected using a remotely operated vehicle (ROV) and ship-based gravity cores. The PVF is expressed as a well-defined seafloor lineation marked by subtle along-strike bends. Right-stepping transtensional bends exert first-order control on sediment flow dynamics and the spatial distribution of Holocene depocenters; deformed strata within a small pull-apart basin record punctuated growth faulting associated with at least three Holocene surface ruptures. An upper (shallower) landslide scarp, a buried sedimentary mound, and a deeper scarp have been right-laterally offset across the PVF by 55 ± 5, 52 ± 4 , and 39 ± 8 m, respectively. The ages of the upper scarp and buried mound are approximately 31 ka; the age of the deeper scarp is bracketed to 17-24 ka. These three piercing points bracket the late Pleistocene to present slip rate to 1.3-2.8 mm/yr and provide a best estimate of 1.6-1.9 mm/yr. The deformation observed along the PVF is characteristic of strike-slip faulting and accounts for 20-30% of the total right-lateral slip budget accommodated offshore Southern California.

  9. The Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys

    Science.gov (United States)

    Brothers, Daniel S.; Conrad, James E.; Maier, Katherine L.; Paull, Charles K.; McGann, Mary L.; Caress, David W.

    2015-01-01

    The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp subbottom profiles were acquired with an autonomous underwater vehicle (AUV) along the main trace of PVF in water depths between 250 and 600 m. Radiocarbon dates were obtained from vibracores collected using a remotely operated vehicle (ROV) and ship-based gravity cores. The PVF is expressed as a well-defined seafloor lineation marked by subtle along-strike bends. Right-stepping transtensional bends exert first-order control on sediment flow dynamics and the spatial distribution of Holocene depocenters; deformed strata within a small pull-apart basin record punctuated growth faulting associated with at least three Holocene surface ruptures. An upper (shallower) landslide scarp, a buried sedimentary mound, and a deeper scarp have been right-laterally offset across the PVF by 55 ± 5, 52 ± 4 , and 39 ± 8 m, respectively. The ages of the upper scarp and buried mound are approximately 31 ka; the age of the deeper scarp is bracketed to 17–24 ka. These three piercing points bracket the late Pleistocene to present slip rate to 1.3–2.8 mm/yr and provide a best estimate of 1.6–1.9 mm/yr. The deformation observed along the PVF is characteristic of strike-slip faulting and accounts for 20–30% of the total right-lateral slip budget accommodated offshore Southern California.

  10. Terrestrial cosmogenic surface exposure dating of moraines at Lake Tahoe in the Sierra Nevada of California and slip rate estimate for the West Tahoe Fault

    Science.gov (United States)

    Pierce, Ian K. D.; Wesnousky, Steven G.; Owen, Lewis A.

    2017-12-01

    Two sets of Pleistocene moraines (Tioga and Tahoe) are preserved at Cascade Lake along the west side of Lake Tahoe. The 10Be terrestrial cosmogenic nuclide surface exposure ages for two younger Tioga moraines yield an average age of 22.3 ± 1.2 ka, coincident with the global Last Glacial Maximum. The ages suggest that the Tioga glaciation may have reached its maximum several thousand years earlier in the Lake Tahoe basin than to the south along the east flank of the Sierra Nevada. The oldest 10Be age (120 ± 8 ka) determined for an additional suite of 10 boulders exhibiting significant scatter in 10Be ages is interpreted to be the minimum age of formation for older Tahoe moraines in the Tahoe basin, suggesting they were deposited during marine oxygen isotope stage 6. The moraines at Cascade Lake are displaced by the West Tahoe Fault that strikes northward for 45 km along the western edge of the Lake Tahoe basin. Vertical displacements of the crests of the Tahoe and Tioga moraines are 59 ± 10 and 32 ± 12 m respectively. Averaged over the time since the formation of the Tahoe and Tioga moraines, the average vertical separation rates are < 0.5 ± 0.1 and 1.4 ± 0.7 mm/y respectively. The measured vertical separation across the broad graben on the Tioga moraine may be accentuated by its deposition on a preexisting scarp and, in this regard, the increase in slip rate since the Tioga glaciation may be apparent rather than real. The fault slip rate and accompanying horizontal rate of extension averaged over the time since the formation of the older Tahoe moraines are respectively 0.6 ± 0.2 and 0.3 ± 0.2 mm/y. The slip rate averaged over the time since emplacement of the Tahoe moraine is in general accord with prior geologic studies reporting slip rate estimates elsewhere along the fault, and the horizontal extension rate is at the lower end of extension rates estimated by others with geodesy across the Tahoe basin.

  11. Modeling the Effects of a Normal-Stress-Dependent State Variable, Within the Rate- and State-Dependent Friction Framework, at Stepovers and Dip-Slip Faults

    Science.gov (United States)

    Ryan, Kenny J.; Oglesby, David D.

    2017-03-01

    The development of the rate- and state-dependent friction framework (Dieterich Appl Geophys 116:790-806, 1978; J Geophys Res 84, 2161-2168, 1979; Ruina Friction laws and instabilities: a quasistatic analysis of some dry friction behavior, Ph.D. Thesis, Brown Univ., Providence, R.I., 1980; J Geophys Res 88:10359-10370, 1983) includes the dependence of friction coefficient on normal stress (Linker and Dieterich J Geophys Res 97:4923-4940, 1992); however, a direct dependence of the friction law on time-varying normal stress in dynamic stepover and dip-slip fault models has not yet been extensively explored. Using rate- and state-dependent friction laws and a 2-D dynamic finite element code (Barall J Int 178, 845-859, 2009), we investigate the effect of the Linker-Dieterich dependence of state variable on normal stress at stepovers and dip-slip faults, where normal stress should not be constant with time (e.g., Harris and Day J Geophys Res 98:4461-4472, 1993; Nielsen Geophys Res Lett 25:125-128, 1998). Specifically, we use the relation d ψ/d t = -( α/ σ)(d σ/d t) from Linker and Dieterich (J Geophys Res 97:4923-4940, 1992), in which a change in normal stress leads to a change in state variable of the opposite sign. We investigate a range of values for alpha, which scales the impact of the normal stress change on state, from 0 to 0.5 (laboratory values range from 0.2 to 0.56). For stepovers, we find that adding normal-stress dependence to the state variable delays or stops re-nucleation on the secondary fault segment when compared to normal-stress-independent state evolution. This inhibition of jumping rupture is due to the fact that re-nucleation along the secondary segment occurs in areas of decreased normal stress in both compressional and dilational stepovers. However, the magnitude of such an effect differs between dilational and compressional systems. Additionally, it is well known that the asymmetric geometry of reverse and normal faults can lead to greater

  12. A kinetic model for estimating net photosynthetic rates of cos lettuce leaves under pulsed light.

    Science.gov (United States)

    Jishi, Tomohiro; Matsuda, Ryo; Fujiwara, Kazuhiro

    2015-04-01

    Time-averaged net photosynthetic rate (P n) under pulsed light (PL) is known to be affected by the PL frequency and duty ratio, even though the time-averaged photosynthetic photon flux density (PPFD) is unchanged. This phenomenon can be explained by considering that photosynthetic intermediates (PIs) are pooled during light periods and then consumed by partial photosynthetic reactions during dark periods. In this study, we developed a kinetic model to estimate P n of cos lettuce (Lactuca sativa L. var. longifolia) leaves under PL based on the dynamics of the amount of pooled PIs. The model inputs are average PPFD, duty ratio, and frequency; the output is P n. The rates of both PI accumulation and consumption at a given moment are assumed to be dependent on the amount of pooled PIs at that point. Required model parameters and three explanatory variables (average PPFD, frequency, and duty ratio) were determined for the simulation using P n values under PL based on several combinations of the three variables. The model simulation for various PL levels with a wide range of time-averaged PPFDs, frequencies, and duty ratios further demonstrated that P n under PL with high frequencies and duty ratios was comparable to, but did not exceed, P n under continuous light, and also showed that P n under PL decreased as either frequency or duty ratio was decreased. The developed model can be used to estimate P n under various light environments where PPFD changes cyclically.

  13. The Impact of Rate Design and Net Metering on the Bill Savings from Distributed PV for Residential Customers in California

    Energy Technology Data Exchange (ETDEWEB)

    Darghouth, Naim; Barbose, Galen; Wiser, Ryan

    2010-03-30

    Net metering has become a widespread policy in the U.S. for supporting distributed photovoltaics (PV) adoption. Though specific design details vary, net metering allows customers with PV to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption - in effect, compensating the PV generation at retail electricity rates (Rose et al. 2009). While net metering has played an important role in jump-starting the residential PV market in the U.S., challenges to net metering policies have emerged in a number of states and contexts, and alternative compensation methods are under consideration. Moreover, one inherent feature of net metering is that the value of the utility bill savings it provides to customers with PV depends heavily on the structure of the underlying retail electricity rate, as well as on the characteristics of the customer and PV system. Consequently, the value of net metering - and the impact of moving to alternative compensation mechanisms - can vary substantially from one customer to the next. For these reasons, it is important for policymakers and others that seek to support the development of distributed PV to understand both how the bill savings varies under net metering, and how the bill savings under net metering compares to other possible compensation mechanisms. To advance this understanding, we analyze the bill savings from PV for residential customers of California's two largest electric utilities, Pacific Gas and Electric (PG&E) and Southern California Edison (SCE). The analysis is based on hourly load data from a sample of 215 residential customers located in the service territories of the two utilities, matched with simulated hourly PV production for the same time period based on data from the nearest of 73 weather stations in the state.

  14. Estimation of slip rates and seismic hazard parameters using conventional techniques of structural geology in a slow-moving fault: Alhama de Murcia - Alcantarilla segment of the Alhama de Murcia Fault (Murcia, SE Spain)

    Science.gov (United States)

    Herrero-Barbero, Paula; Álvarez-Gómez, José Antonio; Jesús Martínez-Díaz, Jose

    2017-04-01

    The convergence between Nubian and Eurasian plates in the Western Mediterranean is being accommodated by the Eastern Betic Shear Zone, located in Southeastern Iberia. This is a low strain region whose faults show low slip rates and long recurrence periods of their maximum earthquakes, so they do not provide clear evidence of their seismogenic activity. The Alhama de Murcia - Alcantarilla segment, defined as the NE end of the Alhama de Murcia Fault, is one of the structures of the Eastern Betic Shear Zone and there are few in-depth studies about its seismic potential. In order to assess the seismogenic potential and slip-rate of this segment we have carried out a structural analysis. We have built a 3D geological model of the area where the fault is currently bounding the Neogene Fortuna basin. The structural model is based on seismic reflection profiles which have been later input in MOVE, structural modelling and analysis software. The analysis of the model has revealed several structural features related to positive inversion tectonics in Fortuna basin, specifically a typical "harpoon" structure whose deformation is estimated to have begun since Upper Miocene (Messinian). Geometric models and area balance methods (e.g. depth-to-detachment method) applied to the previously mentioned structure have allowed to estimate the heave of the fault, representing the amount of shortening observed in the fault section during its recent activity. The horizontal shortening rate estimated is between 0.09 and 0.26 mm/yr during the last 5.3 - 2.6 Ma. Projecting the obtained shortening onto the fault plane and considering the present regional tectonic shortening it has been possible to obtain a net slip rate between 0.13 and 0.37 mm/yr. Such parameters suggest that the Alhama de Murcia - Alcantarilla segment has less activity than other segments of the fault. The result obtained is consistent with the fact that the Carrascoy Fault, oriented parallel and located to the south of the

  15. Net herbage accumulation rate and crude protein content of Urochloa brizantha cultivars under shade intensities

    Directory of Open Access Journals (Sweden)

    Paulo Roberto de Lima Meirelles

    2013-12-01

    Full Text Available The use of silvopastoral systems is a sustainable alternative for animal production in various regions of the Brazil. However to obtain satisfactory results in these systems, the selection of forage species that grows well in the shade should be done. The tolerance of plants to light restriction and the correctly choice of species, considering good nutritional values for these conditions has great importance. The study of artificial shading for forage production helps the clarification of issues related to the behavior of plants under reduced light prior to use in integrations with forests. The aim of the study was to evaluate the net herbage accumulation rate of forage (HAR and crude protein (CP of Urochloa brizantha cultivars (Marandu and Piatã under natural light and shading of 30 and 60%. The experiment was conducted at FMVZ - UNESP, Botucatu. The experimental design was a randomized block in factorial arrangement 3 x 2 (three shading levels: 0, 30 and 60%, two cultivars: Marandu and Piatã with three replications and repeated measures (3 cuts. Sample collection occurred when the cultivars reached 35 cm in height. The treatments with shading showed lower cutting intervals as compared to those subjected to full sunlight, because they have reached in a shorter time to time as determined cut-off criterion (mean of 37, 45 and 61 days for reduction of 60%, reduction of 30% and full sun. Significant effects (P<0.05 interaction cultivar x shade x cut on the net herbage accumulation rate (HAR. Most HAR (P<0.05 was observed for cv. Marandu 60% reduction in lightness (127 kg/ha/day due to increased production of stem during the first growing cycle. The lower HAR also occurred to Marandu, but under natural light in the third cut (34 kg/ha/day due to adverse weather conditions during the growth interval. The shadow effect and the cutting (P<0.05 affected CP. The percentage of CP on cultivars showed the highest values (average value of 9.27% in 60

  16. [Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

    Science.gov (United States)

    Zheng, You-Fei; Ni, Yan-Li; Mai, Bo-Ru; Wu, Rong-Jun; Feng, Yan; Sun, Jian; Li, Jian; Xu, Jing-Xin

    2011-06-01

    Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.

  17. Shell Tectonics: A Mechanical Model for Strike-slip Displacement on Europa

    Science.gov (United States)

    Rhoden, Alyssa Rose; Wurman, Gilead; Huff, Eric M.; Manga, Michael; Hurford, Terry A.

    2012-01-01

    We introduce a new mechanical model for producing tidally-driven strike-slip displacement along preexisting faults on Europa, which we call shell tectonics. This model differs from previous models of strike-slip on icy satellites by incorporating a Coulomb failure criterion, approximating a viscoelastic rheology, determining the slip direction based on the gradient of the tidal shear stress rather than its sign, and quantitatively determining the net offset over many orbits. This model allows us to predict the direction of net displacement along faults and determine relative accumulation rate of displacement. To test the shell tectonics model, we generate global predictions of slip direction and compare them with the observed global pattern of strike-slip displacement on Europa in which left-lateral faults dominate far north of the equator, right-lateral faults dominate in the far south, and near-equatorial regions display a mixture of both types of faults. The shell tectonics model reproduces this global pattern. Incorporating a small obliquity into calculations of tidal stresses, which are used as inputs to the shell tectonics model, can also explain regional differences in strike-slip fault populations. We also discuss implications for fault azimuths, fault depth, and Europa's tectonic history.

  18. The Impact of Rate Design and Net Metering on the Bill Savings from Distributed PV for Residential Customers in California

    Energy Technology Data Exchange (ETDEWEB)

    Energy and Resources Group, University of California, Berkeley; Darghouth, Naim R.; Barbose, Galen; Wiser, Ryan

    2011-06-01

    Net metering has become a widespread mechanism in the U.S. for supporting customer adoption of distributed photovoltaics (PV), but has faced challenges as PV installations grow to a larger share of generation in a number of states. This paper examines the value of the bill savings that customers receive under net metering, and the associated role of retail rate design, based on a sample of approximately two hundred residential customers of California's two largest electric utilities. We find that the bill savings per kWh of PV electricity generated varies by more than a factor of four across the customers in the sample, which is largely attributable to the inclining block structure of the utilities' residential retail rates. We also compare the bill savings under net metering to that received under three potential alternative compensation mechanisms, based on California's Market Price Referent (MPR). We find that net metering provides significantly greater bill savings than a full MPR-based feed-in tariff, but only modestly greater savings than alternative mechanisms under which hourly or monthly net excess generation is compensated at the MPR rate.

  19. Data filtering and expected muon and neutrino event rates in the KM3NeT neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Shanidze, Rezo [ECAP, University of Erlangen-Nuremberg, Erwin-Rommel-Str.1, 91058 Erlangen (Germany); Collaboration: ANTARES-KM3NeT-Erlangen-Collaboration

    2011-07-01

    KM3NeT is a future Mediterranean deep sea neutrino telescope with an instrumented volume of several cubic kilometres. The neutrino and muon events in KM3NeT will be reconstructed from the signals collected from the telescope's photo detectors. However, in the deep sea the dominant source of photon signals are the decays of K40 nuclei and bioluminescence. The selection of neutrino and muon events requires the implementation of fast and efficient data filtering algorithms for the reduction of accidental background event rates. Possible data filtering and triggering schemes for the KM3NeT neutrino telescope and expected muon and neutrino event rates are discussed.

  20. Temporal Controls on Uplift and Slip Rates for the Puente Hills and Santa Ana Mountains, Southern Los Angeles Basin, Orange County, California

    Science.gov (United States)

    Gath, E. M.; Grant, L. B.; Owen, L. A.

    2006-12-01

    The Puente Hills (PH) are seismically active and tectonically uplifted by the Puente Hills Blind Thrust fault (PHBTF). The rate of uplift, and consequently, the late Quaternary slip rate of the eastern part of the PHBTF, herein named the Santa Ana segment, can be constrained by mapping and dating Quaternary stream terraces and strath surfaces in the Santa Ana River Canyon. The PH are cut by the 2-3 mm/yr right-lateral Whittier fault, itself capable of M6.7-7.2 earthquakes. The 7 mapped terraces and strath surfaces of the PH are cut by the Whittier fault with minimal vertical separation. OSL dating, soil age estimates, and correlation with sea level highstands constrains the PH uplift rate to 0.6-1.4 mm/yr based on OSL dates, and 0.2-0.8 mm/yr from other methods. The rates overlap in the range 0.6-0.8 mm/yr, and we propose that this is the most reliable estimate of uplift rate because it is based on several methods. An uplift rate of 0.6-0.8 mm/yr for the PH is also consistent with a 500 700 ka emergent age based on our geomorphic analysis of PH drainage basin development. Using a 30° dip angle produces a slip rate on the Santa Ana segment of the PHBTF of 1.2-1.6 mm/yr. Preliminary tectonic geomorphic analysis of the Santa Ana Mountains (SAM) suggests that they too are being uplifted and are probably seismically active. Shorelines preserved on the lower foothills of Peralta and Loma Ridges were correlated to eustatic sea levels for age estimations. Mapping and dating of terraces in the Santiago Creek drainage, and the older marine terraces indicates that the SAM are uplifting at 0.2-0.7 mm/yr, probably due to a blind thrust associated with partial termination of the Elsinore fault.

  1. Surface slip during large Owens Valley earthquakes

    KAUST Repository

    Haddon, E. K.

    2016-01-10

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from approximate to 1.0 to 6.0 m and average 3.31.1 m (2 sigma). Vertical offsets are predominantly east-down between approximate to 0.1 and 2.4 m, with a mean of 0.80.5 m. The average lateral-to-vertical ratio compiled at specific sites is approximate to 6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.41.5 m, corresponding to a geologic M-w approximate to 7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.12.0 m, 12.8 +/- 1.5 m, and 16.6 +/- 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between approximate to 0.6 and 1.6 mm/yr (1 sigma) over the late Quaternary.

  2. Low inflation, a high net savings surplus and institutional restrictions keep the Japanese long-term interest rate low

    NARCIS (Netherlands)

    Jansen, Pieter W.

    2006-01-01

    This paper explains that the interest rate on long-term Japanese government bonds is low in comparison with other industrialised countries for four main reasons: lower inflation, net savings surplus, institutional restrictions and home bias. Monetary policy and institutionalised purchases of

  3. Slip Rates and Scarp Profiles, Using Terrestrial LiDAR to Quantify Deformation on the Aberdeen Fault, South-Eastern California

    Science.gov (United States)

    Gold, P.; Cowgill, E.

    2008-12-01

    High resolution topographic measurements form the basis for slip-rate studies along active fault systems. However, meter-scale features such as fault scarps or offset terrace risers are insufficiently resolved on available remotely-sensed digital elevation models (e.g., 10 m NED), rendering it necessary to make field- based topographic measurements. Terrestrial or tripod mounted LiDAR (T-LiDAR) is a recent technology that has proved useful for making these types of high resolution measurements. In this study we used T-LiDAR to constrain the morphology of a series of fault scarps offsetting an alluvial fan and the flank of a cinder cone along the Aberdeen fault in the eastern Owens Valley. This site lies on the western edge of the Eastern California Shear Zone (ECSZ), a region defined by northwest striking right lateral faulting in south eastern California and western Nevada that accommodates 20-25% of Pacific-North American relative plate motion. The Aberdeen fault is one of a series of northeast striking normal faults that are thought to transfer slip from west to east within the ECSZ. With the T-LiDAR unit, we collected a ~17 million point data set covering an area of ~350 x 150 m from which we generated a 20cm DEM. These data allowed us to study and measure in great detail the series of fault scarps that offset the flank of the cinder cone and the alluvial fan. Located at the northeast end of the Aberdeen fault, this series of scarps exhibits a ~70° change in azimuth moving east along strike as the fault curves into the range front. Using a hillshade image created from the 20cm DEM, we selected three points from one continuous scarp that offsets the fan and the cinder cone from which we calculated a fault dip of 39°. The high resolution of the hillshade DEM also proved critical in interpreting slip history on this section of the Aberdeen fault by showing definitive evidence for two faulting events. Using a series of scarp profiles derived from the T-LiDAR data

  4. Net Metering and Market Feedback Loops: Exploring the Impact of Retail Rate Design on Distributed PV Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Darghouth, Naïm R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Barbose, Galen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-13

    The substantial increase in deployment of customer-sited solar photovoltaics (PV) in the United States has been driven by a combination of steeply declining costs, financing innovations, and supportive policies. Among those supportive policies is net metering, which in most states effectively allows customers to receive compensation for distributed PV generation at the full retail electricity price. The current design of retail electricity rates and the presence of net metering have elicited concerns that the possible under-recovery of fixed utility costs from PV system owners may lead to a feedback loop of increasing retail prices that accelerate PV adoption and further rate increases. However, a separate and opposing feedback loop could offset this effect: increased PV deployment may lead to a shift in the timing of peak-period electricity prices that could reduce the bill savings received under net metering where time-varying retail electricity rates are used, thereby dampening further PV adoption. In this paper, we examine the impacts of these two competing feedback dynamics on U.S. distributed PV deployment through 2050 for both residential and commercial customers, across states. Our results indicate that, at the aggregate national level, the two feedback effects nearly offset one another and therefore produce a modest net effect, although their magnitude and direction vary by customer segment and by state. We also model aggregate PV deployment trends under various rate designs and net-metering rules, accounting for feedback dynamics. Our results demonstrate that future adoption of distributed PV is highly sensitive to retail rate structures. Whereas flat, time-invariant rates with net metering lead to higher aggregate national deployment levels than the current mix of rate structures (+5% in 2050), rate structures with higher monthly fixed customer charges or PV compensation at levels lower than the full retail rate can dramatically erode aggregate customer

  5. High-rate GPS results for the April 2012 Sumatra earthquake sequence, an unusual, complex, and very large intraplate strike-slip event

    Science.gov (United States)

    Hill, E. M.; Hermawan, I.; Lay, T.; Yue, H.; Banerjee, P.; Qiu, Q.; Macpherson, K. A.; Feng, L.; Tsang, L. L.; Lubis, A.; Tapponnier, P.; Sieh, K. E.

    2012-12-01

    The 11 April 2012 Mw 8.6 Sumatra earthquake was one of the largest strike-slip earthquakes ever recorded, and also one of the largest intraplate earthquakes. It was followed 2 hours later by another great earthquake, of Mw 8.2, in a similar location. The events occurred ~400 km from northern Sumatra, on the oceanic side of the Sunda megathrust. The event was recorded by high-rate GPS stations from our 50-station Sumatra GPS Array (SuGAr). We will present the coseismic displacements and constraints on slip obtained from this network. The location of the events is very interesting. Scientists have long been puzzled by the nature and location of the boundary between the Indian and Australian plates in the depths of the Indian Ocean. Because of the resistance provided by the collision of India with Tibet far to the north, the Indian plate is moving relatively northwards at about 1 cm/yr slower than the Australian plate; this difference in velocity causes strain between the Indian and Australian plates. These earthquakes provide important new evidence that this strain is reactivating a system of faults on the seafloor that were inherited from an older geological epoch, and bring up questions about why this deformation appears to be diffuse, rather than behaving as a proper plate boundary. The events also highlight a back-and-forth interaction between the intraplate faults and the Sunda megathrust; the 2004 megathrust event brought these earthquakes ahead in time, but these earthquakes will in turn have stressed the megathrust. Published seismological results have indicated great complexity in the rupture patterns for these events, with a cascading failure of multiple conjugate faults. Surprisingly, the majority of slip seems to have occurred on the WNW-trending, right-lateral faults, rather than the NNE-trending left-lateral faults that are prominent features of the seafloor. The seismological results also show that the ruptures are likely to have extended from the

  6. The last interglacial period at Guantanamo Bay, Cuba and an estimate of late Quaternary tectonic uplift rate in a strike-slip regime

    Science.gov (United States)

    Schweig, E. S.; Muhs, D. R.; Simmons, K. R.; Halley, R. B.

    2015-12-01

    Guantanamo Bay, Cuba is an area dominated by a strike-slip tectonic regime and is therefore expected to have very low Quaternary uplift rates. We tested this hypothesis by study of an unusually well preserved emergent reef terrace around the bay. Up to 12 m of unaltered, growth-position reef corals are exposed at about 40 sections examined around ˜40 km of coastline. Maximum reef elevations in the protected, inner part of the bay are ˜11-12 m, whereas outer-coast shoreline angles of wave-cut benches are as high as ˜14 m. Fifty uranium-series analyses of unrecrystallized corals from six localities yield ages ranging from ˜134 ka to ˜115 ka, when adjusted for small biases due to slightly elevated initial 234U/238U values. Thus, ages of corals correlate this reef to the peak of the last interglacial period, marine isotope stage (MIS) 5.5. Previously, we dated the Key Largo Limestone to the same high-sea stand in the tectonically stable Florida Keys. Estimates of paleo-sea level during MIS 5.5 in the Florida Keys are ~6.6 to 8.3 m above present. Assuming a similar paleo-sea level in Cuba, this yields a long-term tectonic uplift rate of 0.04-0.06 m/ka over the past ~120 ka. This estimate supports the hypothesis that the tectonic uplift rate should be low in this strike-slip regime. Nevertheless, on the southeast coast of Cuba, east of our study area, we have observed flights of multiple marine terraces, suggesting either (1) a higher uplift rate or (2) an unusually well-preserved record of pre-MIS 5.5 terraces not observed at Guantanamo Bay.

  7. Gill net selectivity and catch rates of pelagic fish in tropical coastal ...

    African Journals Online (AJOL)

    The fish species and size selectivity of gillnets design with monofilament nylon polyethylene netting materials were investigated in Lagos Lagoon, Nigeria between September and December 2005. The gillnets floats and sinkers were improvised from rubber slippers and lead metallic objects which were attached at intervals ...

  8. [Effects of lead stress on net photosynthetic rate, SPAD value and ginsenoside production in Ginseng (Panax ginseng)].

    Science.gov (United States)

    Liang, Yao; Jiang, Xiao-Li; Yang, Fen-Tuan; Cao, Qing-Jun; Li, Gang

    2014-08-01

    The paper aimed to evaluate the effects of lead stress on photosynthetic performance and ginsenoside content in ginseng (Panax ginseng). To accomplish this, three years old ginseng were cultivated in pot and in phytotron with different concentrations of lead, ranging from 0 to 1000 mg x kg(-1) soil for a whole growth period (about 150 days). The photosynthetic parameters in leaves and ginsenoside content in roots of ginseng were determined in green fruit stage and before withering stage, respectively. In comparison with the control, net photosynthetic rate and SPAD value in ginseng leaves cultivated with 100 and 250 mg x kg(-1) of lead changed insignificantly, however, ginseng supplied with 500 and 1 000 mg x kg(-1) of lead showed a noticeably decline in the net rate of photosynthesis and SPAD value (P lead, with decline of 57.8%,11.0%, respectively. Total content of ginsenoside in ginseng roots cultivated with 100 mg x kg(-1) of lead showed insignificantly change compared to the control, but the content increased remarkably in treatments supplied with 250, 500, 1 000 mg x kg(-1) of lead (P lead. The net photosynthetic rate and SPAD value in leaves of ginseng both showed significantly negative linear correlations with lead stress level (P lead concentration was also observed (P lead negatively affects photosynthetic performance in ginseng leaves, but benefits for accumulation of secondary metabolism (total content of ginsenoside) in ginseng root.

  9. Slip dynamics in an analogue faultzone

    Science.gov (United States)

    Rudolf, Michael; Rosenau, Matthias; Oncken, Onno

    2017-04-01

    Elastic stress in the lithosphere releases through slip along pre-existing planes of weakness (fault zones). Slip events may occur on many spatial and temporal scales. They range from short-term localised seismic slip (earthquakes) to aseismic slip transients and long-term distributed slip in cataclastic or ductile shear zones. The interplay of seismic and aseismic fault slip is poorly understood, potentially complex and very costly to model numerically. Therefore, we designed an analogue experiment using a rate-and-state frictional material (fused glass beads), that shows unstable (seismic) and stable (aseismic) slip. This is embedded in an elastic material (ballistic gelatin) that models upper crustal elastic rebound. In the analogue model presented here, we examine the influence of multiple parameters on the slip dynamics and overall statistics of ruptures within a glass bead shear zone. We use a customised rotary shear apparatus (Schulze ring-shear tester) to monitor shear stress during shear. The apparatus allows a direct control of shear rate and normal stress. Its transparent lid enables concurrent monitoring of the frictional contact surface. Digital image correlation is used to measure on-fault deformation. Because of the rate-and-state frictional properties of glass beads (a-b = -0.0138), the used setup produces regular stick-slip events under certain normal loading and strain rate conditions. Preliminary analysis shows the following: The events feature statistics similar to natural slip systems, i.e. a magnitude distribution similar to single faults. Estimated moment magnitudes of the laboratory earthquakes range from MW = -7 to -6. A Gutenberg-Richter like decay up to a certain corner magnitude followed by a characteristic peak is observable. With decreasing loading rate the recurrence time and size of events increase exponentially with exponents similar to natural events. Rupture dynamics are characterised by a transition from two-dimensional crack

  10. Locking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010

    KAUST Repository

    Metzger, Sabrina

    2011-11-01

    Located at the northern shore of Iceland, the Tjörnes Fracture Zone (TFZ) is a 120 km offset in the mid-Atlantic Ridge that connects the offshore Kolbeinsey Ridge to the on-land Northern Volcanic Zone. This transform zone is seismically one of the most active areas in Iceland, exposing the population to a significant risk. However, the kinematics of the mostly offshore area with its complex tectonics have not been adequately resolved and the seismic potential of the two main transform structures within the TFZ, the Grímsey Oblique Rift (GOR) and the Húsavík Flatey Fault (HFF) in particular, is not well known. In summer 2006, we expanded the number of continuous GPS (CGPS) stations in the area from 4 to 14. The resulting GPS velocities after four years of data collection show that the TFZ accommodates the full plate motion as it is predicted by the MORVEL plate motion model. In addition, ENVISAT interferograms reveal a transient uplift signal at the nearby Theistareykir central volcano with a maximum line-of-sight uplift of 3 cm between summers of 2007 and 2008. We use a combination of an interseismic backslip and a Mogi model in a homogeneous, elastic half-space to describe the kinematics within the TFZ. With a non-linear optimization approach we fit the GPS observations and estimate the key model parameters and their uncertainties, which are (among others) the locking depth, the partition of the transform motion between the two transform structures within the TFZ and the slip rate on the HFF. We find a shallow locking depth of 6.3+1.7- 1.2 km and transform motion that is accommodated 34 ± 3 per cent by the HFF and 66 ± 3 per cent by the GOR, resulting in a slip velocity of 6.6 ± 0.6 mm yr-1 for the HFF. Assuming steady accumulation since the last two large M6.5 earthquakes in 1872 the seismic potential of the fault is equivalent to a Mw6.8 ± 0.1 event.

  11. Slip rates of active thrusts at the front of the Precordillera revealed by exposure dating and fault scarp profiles, Mendoza, Argentina

    Science.gov (United States)

    Schmidt, Silke; Hetzel, Ralf; Kuhlmann, Jan; Mingorance, Francisco; Ramos, Victor

    2010-05-01

    Although large historical earthquakes occurred in the Andean back-arc region between 28° and 34°S, the slip rates of active reverse faults remain unknown; hence the seismic hazard related to these faults is poorly constrained. Here we report long-term slip rates for two faults - the Peñas and the Cal thrust - which define the front of the Andean Precordillera north of Mendoza. Both thrusts displace several Late Pleistocene to Holocene river terraces and form well-preserved fault scarps. At the Peñas thrust three terraces (T1, T2, and T3) are displaced vertically by ~0.9, ~1.9 and ~11 m, respectively. 10Be exposure dating constrains the age of T2 and T3 as 2.9 ± 0.8 ka and 11.1 ± 1.7 ka, which yields an uplift rate of 0.9 ± 0.1 mm/a. The horizontal shortening rate of the Peñas thrust - calculated by using the age of T3 and the dip angle of 25° - is 1.9 ± 0.2 mm/a. At the Cal thrust a fault scarp has displaced a terrace with a maximum age of 12 ka by 7 m. As the Cal thrust dips ~25°, this yields a shortening rate of ≥ 1.3 mm/a. Our results demonstrate that the two thrusts accomodate about half of the present-day shortening rate in the back-arc region of the Andes, which is constrained as 4.5 ± 1.7 mm/a (Brooks et al., 2003). Using the compilation of Well & Coppersmith (1994), the 50-km-long Peñas and the 31-km-long Cal thrusts are capable of producing earthquakes with a magnitude of Mw 6.7 to 7.0. This is supported by a magnitude Ms ~ 7.0 earthquake on the Cal fault, which devastated Mendoza in 1861 and killed two thirds of its population. Earthquakes of this magnitude have presumably generated the smallest fault scarps (~0.9 m vertical offset) present at both thrusts. The higher scarps are interpreted to record multiple offsets generated during several Holocene earthquakes. References Brooks, B.A., Bevis, M., Smalley, R., Kendrick, E., Manceda, R., Lauria, E., Maturana, R. & Araujo, M. (2003): Crustal motion in the Southern Andes (26° - 36°S): Do

  12. Net Reaction Rate and Neutrino Cooling Rate for the Urca Process in Departure from Chemical Equilibrium in the Crust of Fast-accreting Neutron Stars

    Science.gov (United States)

    Wang, Wei-Hua; Huang, Xi; Zheng, Xiao-Ping

    We discuss the effect of compression on Urca shells in the ocean and crust of accreting neutron stars, especially in superbursting sources. We find that Urca shells may be deviated from chemical equilibrium in neutron stars which accrete at several tenths of the local Eddington accretion rate. The deviation depends on the energy threshold of the parent and daughter nuclei, the transition strength, the temperature, and the local accretion rate. In a typical crust model of accreting neutron stars, the chemical departures range from a few tenths of kBT to tens of kBT for various Urca pairs. If the Urca shell can exist in crusts of accreting neutron stars, compression may enhance the net neutrino cooling rate by a factor of about 1-2 relative to the neutrino emissivity in chemical equilibrium. For some cases, such as Urca pairs with small energy thresholds and/or weak transition strength, the large chemical departure may result in net heating rather than cooling, although the released heat can be small. Strong Urca pairs in the deep crust are hard to be deviated even in neutron stars accreting at the local Eddington accretion rate.

  13. Net accumulation rates derived from ice core stable isotope records of Pío XI glacier, Southern Patagonia Icefield

    Directory of Open Access Journals (Sweden)

    M. Schwikowski

    2013-10-01

    Full Text Available Pío XI, the largest glacier of the Southern Patagonia Icefield, reached its neoglacial maximum extent in 1994 and is one of the few glaciers in that area which is not retreating. In view of the recent warming it is important to understand glacier responses to climate changes. Due to its remoteness and the harsh conditions in Patagonia, no systematic mass balance studies have been performed. In this study we derived net accumulation rates for the period 2000–2006 from a 50 m (33.2 4 m weq ice core collected in the accumulation area of Pío XI (2600 m a.s.l., 49°16'40"S, 73°21'14"W. Borehole temperatures indicate near temperate ice, but the average melt percent is only 16 ± 14%. Records of stable isotopes are well preserved and were used for identification of annual layers. Net accumulation rates range from 3.4–7.1 water equivalent (m weq with an average of 5.8 m weq, comparable to precipitation amounts at the Chilean coast, but not as high as expected for the Icefield. Ice core stable isotope data correlate well with upper air temperatures and may be used as temperature proxy.

  14. Effect of stroke rate on the distribution of net mechanical power in rowing

    NARCIS (Netherlands)

    Hofmijster, M.J.; Landman, E.H.; Smith, R.M.; van Soest, A.J.

    2007-01-01

    The aim of this study was to assess the effect of manipulating stroke rate on the distribution of mechanical power in rowing. Two causes of inefficient mechanical energy expenditure were identified in rowing. The ratio between power not lost at the blades and generated mechanical power (P̄

  15. Whillans Ice Plain Stick Slip

    Science.gov (United States)

    Lipovsky, B.; Dunham, E. M.

    2015-12-01

    Concern about future sea level rise motivates the study of fast flowing ice. The Whillans Ice Plain (WIP) region of the West Antarctic Ice Sheet is notable for decelerating from previously fast motion during the instrumental record. Since most ice flux in Antarctica occurs through ice streams, understanding the conditions that cause ice stream stagnation is of basic importance in understanding the continent's contribution to future sea level rise. Although recent progress has been made in understanding the relationship between basal conditions and ice stream motion, direct observation of the temporal variation in subglacial conditions during ice stream stagnation has remained elusive. The Whillans Ice Plain flows to the sea mostly by way of stick-slip motion. We present numerical simulations of this stick-slip motion that capture the inertial dynamics, seismic waves, and the evolution of sliding with rate- and state-dependent basal friction. Large scale stick-slip behavior is tidally modulated and encompasses the entire WIP. Sliding initiates within one of several locked regions and then propagates outward with low average rupture velocity (~ 200 m/s). Sliding accelerates over a period of 200 s attain values as large as 65 m/d. From Newton's second law, this acceleration is ~ T / (rho H) for average shear stress drop T, ice thickness H, and ice density rho. This implies a 3 Pa stress drop that must be reconciled with the final stress drop of 300 Pa inferred from the total slip and fault dimensions. A possible explanation of this apparent discrepancy is that deceleration of the ice is associated with a substantial decrease in traction within rate-strengthening regions of the bed. During these large-scale sliding events, m-scale patches at the bed produce rapid (20 Hz) stick-slip motion. Each small event occurs over ~ 1/100 s, produces ~ 40 microns of slip, and gives rise to a spectacular form of seismic tremor. Variation between successive tremor episodes allows us

  16. The contralateral slip. An avoidable complication and indication for prophylactic pinning in slipped upper femoral epiphysis.

    Science.gov (United States)

    MacLean, J G B; Reddy, S K

    2006-11-01

    Between July 1994 and June 2004, 60 patients with 76 slipped upper femoral epiphyses were managed within the adult trauma service of three hospitals. Treatment was by a single cannulated screw. Of these cases, 53 were unilateral, in 17 of which uncomplicated prophylactic fixation of the contralateral hip was performed. Of the other 36 cases, nine presented with a subsequent slip despite ongoing out-patient care. The subsequent slip was unpredictable in timing and unrelated to the age at the initial slip. It was more often unstable and in one case avascular necrosis developed. The overall rate of avascular necrosis, although in accordance with the literature, was 60% in acute unstable slips with a slip angle greater than 40 degrees. In our experience, prophylactic fixation was safer than continued observation of the contralateral hip.

  17. The role of water in slip casting

    Science.gov (United States)

    Mccauley, R. A.; Phelps, G. W.

    1984-01-01

    Slips and casting are considered in terms of physical and colloidal chemistry. Casting slips are polydisperse suspensions of lyophobic particles in water, whose degree of coagulation is controlled by interaction of flocculating and deflocculating agents. Slip casting rate and viscosity are functions of temperature. Slip rheology and response to deflocculating agents varies significantly as the kinds and amounts of colloid modifiers change. Water is considered as a raw material. Various concepts of water/clay interactions and structures are discussed. Casting is a de-watering operation in which water moves from slip to cast to mold in response to a potential energy termed moisture stress. Drying is an evaporative process from a free water surface.

  18. Net Ecosystem Carbon Flux

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Net Ecosystem Carbon Flux is defined as the year-over-year change in Total Ecosystem Carbon Stock, or the net rate of carbon exchange between an ecosystem and the...

  19. Calibrated surface ages for desert pavements from spaceborne radar measurements of surface roughness and application of this new dating method for quantifying tectonic slip rates across the Dead Sea Transform since 1 Ma.

    Science.gov (United States)

    Hetz, Guy; Mushkin, Amit; Beyth, Michael; Baer, Gidon; Sagy, Amir; Blumberg, Dan; Ginat, Hanan

    2017-04-01

    The Dead Sea Transform (DST) accommodates a total of 105 km of sinistral motion between Arabia and the Sinai sub-plate since the Miocene. Previous studies revealed time-averaged slip rates of 5-8 mm/yr since the Miocene that appear to be comparable to more recent slip rates of 3-9 mm/yr inferred from offset late Pleistocene - Holocene geomorphic markers and GPS measurements along the DST. However, quantitative constraints for Plio-Pleistocene slip rates across the transform remain limited because dating efforts of geomorphic features in this age range that were tectonically offset by the DST have been unsuccessful so far. Here, to address this data gap we use a newly established dating approach for desert alluvial surfaces that builds on satellite radar measurements of surface roughness as quantitative proxies for the age of abandoned alluvial surfaces in desert environments. Calibration of the radar measurements against previously obtained 'in-situ' surface ages (e.g., cosmogenic nuclides, luminescence dating) of abandoned alluvial units within the DST region allowed us to use radar to determine surface ages. Sensitivity analyses and validation experiments reveal a minor dependency on lithology, an effective age inversion range of 3 - 1500 ka and overall uncertainty of 35% for the radar-based age estimates. Newly obtained radar ages of 700 and 1000 ka for tectonically offset alluvial fans, which could not be previously dated with 'in-situ' methods, reveal a constant lateral slip rate of 5-10 mm/yr across the DST since 1 Ma. Our results support the hypothesis that crustal velocities between Arabia and the Sinai sub-plate have remained constant since the Miocene.

  20. Increased Ratio of Electron Transport to Net Assimilation Rate Supports Elevated Isoprenoid Emission Rate in Eucalypts under Drought1[W][OPEN

    Science.gov (United States)

    Dani, Kaidala Ganesha Srikanta; Jamie, Ian McLeod; Prentice, Iain Colin; Atwell, Brian James

    2014-01-01

    Plants undergoing heat and low-CO2 stresses emit large amounts of volatile isoprenoids compared with those in stress-free conditions. One hypothesis posits that the balance between reducing power availability and its use in carbon assimilation determines constitutive isoprenoid emission rates in plants and potentially even their maximum emission capacity under brief periods of stress. To test this, we used abiotic stresses to manipulate the availability of reducing power. Specifically, we examined the effects of mild to severe drought on photosynthetic electron transport rate (ETR) and net carbon assimilation rate (NAR) and the relationship between estimated energy pools and constitutive volatile isoprenoid emission rates in two species of eucalypts: Eucalyptus occidentalis (drought tolerant) and Eucalyptus camaldulensis (drought sensitive). Isoprenoid emission rates were insensitive to mild drought, and the rates increased when the decline in NAR reached a certain species-specific threshold. ETR was sustained under drought and the ETR-NAR ratio increased, driving constitutive isoprenoid emission until severe drought caused carbon limitation of the methylerythritol phosphate pathway. The estimated residual reducing power unused for carbon assimilation, based on the energetic status model, significantly correlated with constitutive isoprenoid emission rates across gradients of drought (r2 > 0.8) and photorespiratory stress (r2 > 0.9). Carbon availability could critically limit emission rates under severe drought and photorespiratory stresses. Under most instances of moderate abiotic stress levels, increased isoprenoid emission rates compete with photorespiration for the residual reducing power not invested in carbon assimilation. A similar mechanism also explains the individual positive effects of low-CO2, heat, and drought stresses on isoprenoid emission. PMID:25139160

  1. Uncertainties in the Value of Bill Savings from Behind-the-Meter, Residential Photovoltaic Systems: The Roles of Electricity Market Conditions, Retail Rate Design, and Net Metering

    Science.gov (United States)

    Darghouth, Naim Richard

    Net metering has become a widespread policy mechanism in the U.S. for supporting customer adoption of distributed photovoltaics (PV), allowing customers with PV systems to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption. Although net metering is one of the principal drivers for the residential PV market in the U.S., the academic literature on this policy has been sparse and this dissertation contributes to this emerging body of literature. This dissertation explores the linkages between the availability of net metering, wholesale electricity market conditions, retail rates, and the residential bill savings from behind-the-meter PV systems. First, I examine the value of the bill savings that customers receive under net metering and alternatives to net metering, and the associated role of retail rate design, based on current rates and a sample of approximately two hundred residential customers of California's two largest electric utilities. I find that the bill savings per kWh of PV electricity generated varies greatly, largely attributable to the increasing block structure of the California utilities' residential retail rates. I also find that net metering provides significantly greater bill savings than alternative compensation mechanisms based on avoided costs. However, retail electricity rates may shift as wholesale electricity market conditions change. I then investigate a potential change in market conditions -- increased solar PV penetrations -- on wholesale prices in the short-term based on the merit-order effect. This demonstrates the potential price effects of changes in market conditions, but also points to a number of methodological shortcomings of this method, motivating my usage of a long-term capacity investment and economic dispatch model to examine wholesale price effects of various wholesale market scenarios in the subsequent analysis. By developing

  2. New Data on Quaternary Surface Offset and Slip Rates of the Oquirrh Fault (Utah, USA) from DSMs made with Structure-from-Motion Methods

    Science.gov (United States)

    Bunds, M. P.; Andreini, J.; Larsen, K.; Fletcher, A.; Arnold, M.; Toke, N. A.

    2016-12-01

    We generated two high-resolution digital surface models (DSMs) using imagery collected with inexpensive quadcopters and processed with structure-from-motion software to measure offsets of pluvial Lake Bonneville shorelines along the Oquirrh Fault in Utah, USA. The Oquirrh Fault is a west-dipping normal fault that bounds the populous Tooele Valley and is likely contiguous with the East Great Salt Lake Fault to the north and Southern Oquirrh and Topliff Hill Faults to the south, forming a fault system >200 km long, the second longest in Utah. However, knowledge of the fault's parameters is based primarily on one trenching study on the northern section of the fault (Olig et al., 1996). The two DSMs were made using a 24 Mpixel Sony A5100 and 12 Mpixel GoPro camera, have 5 and 10 cm pixels, and span 3.9 km of the fault's trace at the boundary between its central and southern sections. Vertical RMS error of the DSMs relative to bare-ground checkpoints is 5.8 and 9.5 cm for the Sony and GoPro-derived DSMs, respectively. Shoreline features interpreted to have formed 23,000 ybp (Godsey et al., 2011; Oviatt, 2015) are offset 2.8-3.0, 5.6-6.7, and 8.1-9.3 m, respectively. From these offsets we infer three surface-rupturing earthquakes with displacements of 2.8-3.0, 2.6-3.8, and 1.3-3.8 m, and estimate the slip rate to be 0.24 - 0.37 mm/yr. These results are consistent with those of the prior study to the north, suggesting co-rupturing of the northern, central and northernmost part of the southern section of the fault. In addition, the inferred large single event displacements suggest even longer surface ruptures. We have used the same methods to construct 5 cm pixel DSMs up to 4.4 km2 in area to support several additional paleoseismological, paleotsunami, and neotectonic investigations, which highlights the many benefits to geoscience research of the capacity to quickly produce accurate, high resolution DSMs from inexpensive equipment.

  3. Seismic hazard in low slip rate crustal faults, estimating the characteristic event and the most hazardous zone: study case San Ramón Fault, in southern Andes

    Science.gov (United States)

    Estay, Nicolás P.; Yáñez, Gonzalo; Carretier, Sebastien; Lira, Elias; Maringue, José

    2016-11-01

    Crustal faults located close to cities may induce catastrophic damages. When recurrence times are in the range of 1000-10 000 or higher, actions to mitigate the effects of the associated earthquake are hampered by the lack of a full seismic record, and in many cases, also of geological evidences. In order to characterize the fault behavior and its effects, we propose three different already-developed time-integration methodologies to define the most likely scenarios of rupture, and then to quantify the hazard with an empirical equation of peak ground acceleration (PGA). We consider the following methodologies: (1) stream gradient and (2) sinuosity indexes to estimate fault-related topographic effects, and (3) gravity profiles across the fault to identify the fault scarp in the basement. We chose the San Ramón Fault on which to apply these methodologies. It is a ˜ 30 km N-S trending fault with a low slip rate (0.1-0.5 mm yr-1) and an approximated recurrence of 9000 years. It is located in the foothills of the Andes near the large city of Santiago, the capital of Chile (> 6 000 000 inhabitants). Along the fault trace we define four segments, with a mean length of ˜ 10 km, which probably become active independently. We tested the present-day seismic activity by deploying a local seismological network for 1 year, finding five events that are spatially related to the fault. In addition, fault geometry along the most evident scarp was imaged in terms of its electrical resistivity response by a high resolution TEM (transient electromagnetic) profile. Seismic event distribution and TEM imaging allowed the constraint of the fault dip angle (˜ 65°) and its capacity to break into the surface. Using the empirical equation of Chiou and Youngs (2014) for crustal faults and considering the characteristic seismic event (thrust high-angle fault, ˜ 10 km, Mw = 6.2-6.7), we estimate the acceleration distribution in Santiago and the hazardous zones. City domains that are under

  4. Using Deep Slow Slip in New Zealand to Constrain Slip Partitioning

    Science.gov (United States)

    Bartlow, N. M.; Wallace, L. M.

    2016-12-01

    Underneath New Zealand's North Island, the Pacific plate subducts obliquely beneath the Australian plate. Just to the south, subduction ceases and the plate boundary transitions to the mainly strike-slip, steeply dipping Alpine fault that runs along the South Island. In the region of the southern North Island, the relative plate motion has significant components of both convergence and along strike motion, and slip is partitioned between the main Hikurangi subduction interface and a series of shallower strike-slip faults running thurough the North Island (Wallace and Beavan, GRL, 2010). This region also hosts deep ( 50 km), long duration ( 1 year) slow slip events (SSEs). From early 2013 to early 2016, continuous GPS stations maintained by GeoNet in this region recorded two such deep SSEs on the Hikurangi megathrust. The first SSE occurred on the Kapiti patch, just southwest of the North Island coast. SSEs previous occurred here in 2003 and 2008 (Wallace and Beavan, JGR, 2010). The 2014 Kapiti SSE is unique because it was rapidly decelerated following increased normal stress (clamping) caused by a nearby M 6.3 earthquake (Wallace et al., GRL, 2014). However, GPS data indicates that slip did not stop entirely, and soon after the Manawatu slow slip patch just to the northeast ruptured in another SSE. This patch previously had large SSEs in 2004/2005 and 2010/2011. Given the previous repeat interval of 5.5 years, the 2014/2015 Manawatu SSE is early; however, the record is very short. Here we show Network Inversion Filter derived models of slow slip for the various phases of the Kapiti and Manawatu SSEs, which indicate a possible continuous migration of slip from the Kapiti SSE patch to the Manawatu SSE patch, and we quantify the shear stress increase on the Manawatu patch after the Kapiti SSE. Additionally, we explore allowing the Network Inversion Filter to vary the direction of slip on the plate interface to better fit the data. We estimate how much of the strike-slip

  5. Research of the relationship between delayed fluorescence and net photosynthesis rate in spinach under NaCl stress

    Science.gov (United States)

    Zhang, Lingrui; Xing, Da

    2006-09-01

    Under NaCl stress conditions, the relationship between delayed fluorescence (DF) and net photosynthesis rate (Pn) in detached leaves of spinach (Spinacia oleracea L.) was surveyed. Results showed that the changes in DF intensity of the spinach leaves directly exposed to different NaCl concentrations demonstrated considerably high consistency with that in Pn. Incubation of the leaves in 200mmol/L NaCl induced a gradual increase and subsequent decline of the DF intensity and Pu, whereas incubation of the leaves in 300mmol/L NaCl induced a continuous decline of the DF intensity and Pn, suggesting that DF bad the same response to duration of treatment of different NaC1 concentrations with Pn. Both DF and Pn showed maximal Ca 2+ antagonism effects on stress of high concentration NaC1 when the concentration of CaC1 II reached l5mmolfL. All the results demonstrated that DF has an excellent correlation with Pn and can be used as a sensitive test for the state of photosynthetic apparatus under salt stress physiology.

  6. Modeled dosage-response relationship on the net photosynthetic rate for the sensitivity to acid rain of 21 plant species.

    Science.gov (United States)

    Deng, Shihuai; Gou, Shuzhen; Sun, Baiye; Lv, Wenlin; Li, Yuanwei; Peng, Hong; Xiao, Hong; Yang, Gang; Wang, Yingjun

    2012-08-01

    This study investigated the sensitivity of plant species to acid rain based on the modeled dosage-response relationship on the net photosynthetic rate (P (N)) of 21 types of plant species, subjected to the exposure of simulated acid rain (SAR) for 5 times during a period of 50 days. Variable responses of P (N) to SAR occurred depending on the type of plant. A majority (13 species) of the dosage-response relationship could be described by an S-shaped curve and be fitted with the Boltzmann model. Model fitting allowed quantitative evaluation of the dosage-response relationship and an accurate estimation of the EC(10), termed as the pH of the acid rain resulting in a P (N) 10 % lower than the reference value. The top 9 species (Camellia sasanqua, Cinnamomum camphora, etc. EC(10) ≤ 3.0) are highly endurable to very acid rain. The rare, relict plant Metasequoia glyptostroboides was the most sensitive species (EC(10) = 5.1) recommended for protection.

  7. Mosquito abundance, bed net coverage and other factors associated with variations in sporozoite infectivity rates in four villages of rural Tanzania

    DEFF Research Database (Denmark)

    Kweka, Eliningaya J; Nkya, Watoky M M; Mahande, Aneth M

    2008-01-01

    . Sporozoite infectivity rates, mosquito host blood meal source, bed net coverage and mosquito abundance were assessed in this study. METHODOLOGY: A longitudinal survey was conducted in four villages in two regions of Tanzania. Malaria vectors were sampled using the CDC light trap and pyrethrum spray catch......,628 (81.8%) Anopheles arabiensis, 1,100 (15.9%) Culex quinquefasciatus, 89 (1.4%) Anopheles funestus, and 66 (0.9%) Anopheles gambiae s.s. Of the total mosquitoes collected 3,861 were captured by CDC light trap and 3,022 by the pyrethrum spray catch method. The overall light trap: spray catch ratio was 1.......3:1. Mosquito densities per room were 96.5 and 75.5 for light trap and pyrethrum spray catch respectively. Mosquito infectivity rates between villages that have high proportion of bed net owners and those without bed nets was significant (P

  8. Seismic slip on clay nano-foliation

    Science.gov (United States)

    Aretusini, Stefano; Plümper, Oliver; Spagnuolo, Elena; Di Toro, Giulio

    2017-04-01

    Deformation processes active at seismic slip rates (ca. 1 m/s) on smectite-rich slipping zones are not well understood, although they likely control the mechanical behaviour of: i) subduction zone faults affected by tsunamigenic earthquakes and seismic surface rupturing, and ii) landslide decollements. Here we present a set of rotary experiments performed on water-dampened 2 mm thick clay-rich (70% wt. smectite and 30% wt. opal) gouge layers sheared at slip rates V ranging from 0.01 to 1.5 m/s, for 3 m of displacement under 5 MPa normal stress. Microstructural analyses were conducted on pre- and post-sheared gouges using focused ion beam scanning electron and transmission electron microscopy. All sheared gouges were slip weakening in the first 0.1 m of displacement, with friction coefficient decreasing from 0.4-0.3 to 0.1-0.05. Then, with progressive slip, gouges evolved to slip-strengthening (final friction coefficient of 0.47-0.35) at V ≤0.1 m/s and slip-neutral (final friction of 0.05) at V=1.5 m/s. Despite the large difference in the imposed slip rate and frictional behaviour, the slipping zone always consisted of a nano-foliation defined by sub-micrometric smectite crystals wrapping opal grains. The microstructural differences were (1) the thickness of the slipping zone which decreased from 1.5 mm at V≤0.1 m/s to 0.15 mm at V=1.5 m/s, and (2) the structure of the foliated fabric, which was S/C'-type at V≤0.1 m/s and anastomosing-type at V=1.5 m/s. The presence of a similar nano-foliation in all the smectite-rich wet gouges suggests the activation of similar frictional processes, most likely grain boundary and interlayer frictional sliding aided by water films, operating from sub-seismic to seismic strain rates ( 10-10000 1/s). Water films on crystal boundaries and interlayers possibly control the micro- and nano-mechanics of smectite deformation, therefore influencing the bulk frictional behaviour during seismic slip.

  9. Effects of a clearcut on the net rates of nitrification and N mineralization in a northern hardwood forest, Catskill Mountains, New York, USA

    Science.gov (United States)

    Burns, Douglas A.; Murdoch, Peter S.

    2005-01-01

    The Catskill Mountains of southeastern New York receive among the highest rates of atmospheric nitrogen (N) deposition in eastern North America, and ecosystems in the region may be sensitive to human disturbances that affect the N cycle. We studied the effects of a clearcut in a northern hardwood forest within a 24-ha Catskill watershed on the net rates of N mineralization and nitrification in soil plots during 6 years (1994-1999) that encompassed 3-year pre- and post-harvesting periods. Despite stream NO3- concentrations that increased by more than 1400 ??mol l-1 within 5 months after the clearcut, and three measures of NO3- availability in soil that increased 6- to 8-fold during the 1st year after harvest, the net rates of N mineralization and nitrification as measured by in situ incubation in the soil remained unchanged. The net N-mineralization rate in O-horizon soil was 1- 2 mg N kg-1 day-1 and the net nitrification rate was about 1 mg N kg-1 day-1, and rates in B-horizon soil were only one-fifth to one-tenth those of the O-horizon. These rates were obtained in single 625 m2 plots in the clearcut watershed and reference area, and were confirmed by rate measurements at 6 plots in 1999 that showed little difference in N-mineralization and nitrification rates between the treatment and reference areas. Soil temperature increased 1 ?? 0.8??C in a clearcut study plot relative to a reference plot during the post-harvest period, and soil moisture in the clearcut plot was indistinguishable from that in the reference plot. These results are contrary to the initial hypothesis that the clearcut would cause net rates of these N-cycling processes to increase sharply. The in situ incubation method used in this study isolated the samples from ambient roots and thereby prevented plant N uptake; therefore, the increases in stream NO3- concentrations and export following harvest largely reflect diminished uptake. Changes in temperature and moisture after the clearcut were

  10. Measuring the impact of motivation on achievement and course completion rates in MarineNet distance education

    OpenAIRE

    Lindshield, Timothy D.

    2016-01-01

    Approved for public release; distribution is unlimited The Marine Corps Distance Learning Network (MarineNet) is the primary source for distance education (DE) and online training for the Marine Corps. This research applies the learning theory of human motivation to archival MarineNet data to determine if motivation factors impact academic performance and course completion. The literature on motivation divides this variable into multiple types of intrinsic and extrinsic motivations. Each t...

  11. SLIP CASTING METHOD

    Science.gov (United States)

    Allison, A.G.

    1959-09-01

    S>A process is described for preparing a magnesium oxide slip casting slurry which when used in conjunction with standard casting techniques results in a very strong "green" slip casting and a fired piece of very close dimensional tolerance. The process involves aging an aqueous magnestum oxide slurry, having a basic pH value, until it attains a specified critical viscosity at which time a deflocculating agent is added without upsetting the basic pH value.

  12. In situ filtering rate variability in egg and larval surveys off the Pacific coast of Japan: Do plankton nets clog or over-filter in the sea?

    Science.gov (United States)

    Takasuka, Akinori; Tadokoro, Kazuaki; Okazaki, Yuji; Ichikawa, Tadafumi; Sugisaki, Hiroya; Kuroda, Hiroshi; Oozeki, Yoshioki

    2017-02-01

    In situ filtering rate variability was examined for vertical tows of plankton nets in egg and larval surveys off the Pacific coast of Japan, based on a data set pooled over large spatial and temporal scales (76,444 sampling tows from 1978 to 2013). The filtering rate showed unimodal distributions and was highly variable for the four net types: Long NORPAC (LNP), NORPAC (NOR), Maru-toku B (MTB), and Maru-naka (MNK). Despite the high variability at the individual tow level, the median values of the filtering rate for the overall data approximated the theoretical value of 1.0, in particular, for LNP, although the median values differed among the net types. For LNP, the differences in the median values among the 26 years, the 12 months, and the 4 regions were small relative to the overall variability at the individual level. The present study quantified the extent of underestimation/overestimation when the theoretical value of 1.0 is used due to the lack of the actual filtering rate data. The filtering rate was almost on a balance of resistance effect of net and cod-end, clogging effect of collected organisms, and over-inflow effect of currents over large scales. The present analysis implies that the filtering rate is mainly influenced by small-scale transient variability of ocean conditions such as wind speed, current intensity, rolling, turbulence, and mixing rather than large-scale variability related to climate regime, seasonality, or water masses. The results will allow the utilization of historical data lacking flow-meter data for large-scale comparative analyses.

  13. Slipped Capital Femoral Epiphysis

    Science.gov (United States)

    ... be on crutches?Will my child need physical therapy?Are other treatment options available?My child only has problems in one hip. Is he/she likely to have problems in the other hip?When can my child return to exercise/sports? What kind of exercises are ok? ResourcesSlipped Capital ...

  14. Inorganic glass ceramic slip rings

    Science.gov (United States)

    Glossbrenner, E. W.; Cole, S. R.

    1972-01-01

    Prototypes of slip rings have been fabricated from ceramic glass, a material which is highly resistant to deterioration due to high temperature. Slip ring assemblies were not structurally damaged by mechanical tests and performed statisfactorily for 200 hours.

  15. Geometry and slip rates of active blind thrusts in a reactivated back-arc rift using shallow seismic imaging: Toyama basin, central Japan

    Science.gov (United States)

    Ishiyama, Tatsuya; Kato, Naoko; Sato, Hiroshi; Koshiya, Shin; Toda, Shigeru; Kobayashi, Kenta

    2017-10-01

    Active blind thrust faults, which can be a major seismic hazard in urbanized areas, are commonly difficult to image with seismic reflection surveys. To address these challenges in coastal plains, we collected about 8 km-long onshore high-resolution two-dimensional (2D) seismic reflection data using a dense array of 800 geophones across compressionally reactivated normal faults within a failed rift system located along the southwestern extension of the Toyama trough in the Sea of Japan. The processing of the seismic reflection data illuminated their detailed subsurface structures to depths of about 3 km. The interpreted depth-converted section, correlated with nearby Neogene stratigraphy, indicated the presence of and along-strike variation of previously unrecognized complex thrust-related structures composed of active fault-bend folds coupled with pairs of flexural slip faults within the forelimb and newly identified frontal active blind thrusts beneath the alluvial plain. In addition, growth strata and fold scarps that deform lower to upper Pleistocene units record the recent history of their structural growth and fault activity. This case shows that shallow seismic reflection imaging with densely spaced seismic recorders is a useful tool in defining locations, recent fault activity, and complex geometry of otherwise inaccessible active blind thrust faults.

  16. Association between Slip Severity and Muscle Synergies of Slipping

    Directory of Open Access Journals (Sweden)

    Mohammad Moein Nazifi

    2017-11-01

    Full Text Available Falls impose significant negative impacts to the US population and economy. A significant number of falls may be prevented via appropriate slip-responses since a strong relation exists between slips and falls. More importantly, as severe slips are more prone to result in a fall, identifying severe slippers along with the responsible factors for their adverse motor control and severe slipping should be the highest priority in fall prevention process. Previous studies have suggested that muscle synergies may be building blocks of the central nervous system in controlling motor tasks. Muscle synergies observed during slipping (‘post-slip-initiation synergies’ or ‘just briefly,’ ‘slipping muscle synergies’, may represent the fundamental blocks of the neural control during slipping. Hence, studying the differences in slipping muscle synergies of mild and severe slippers can potentially reveal the differences in their neural control and subsequently, indicate the responsible factors for the adverse post-slip response in severe slippers. Even though the slipping muscle synergies have been investigated before, it still remains unclear on how the slip severity is associated with the slipping muscle synergies. More importantly, muscle synergies can be interpreted not only as neural blocks but also as physical sub-tasks of the main motor task. Hence, studying the differences of slipping synergies of mild and severe slippers would reveal the discrepancies in sub-tasks of their post-slip response. These discrepancies help pinpoint the malfunctioning sub-function associated with inadequate motor response seen in severe slippers. Twenty healthy subjects were recruited and underwent an unexpected slip (to extract their slipping synergies. Subjects were classified into mild and severe slippers based on their Peak Heel Speed. An independent t-test revealed several significant inter-group differences for muscle synergies of mild and severe slippers

  17. Association between Slip Severity and Muscle Synergies of Slipping

    Science.gov (United States)

    Nazifi, Mohammad Moein; Beschorner, Kurt E.; Hur, Pilwon

    2017-01-01

    Falls impose significant negative impacts to the US population and economy. A significant number of falls may be prevented via appropriate slip-responses since a strong relation exists between slips and falls. More importantly, as severe slips are more prone to result in a fall, identifying severe slippers along with the responsible factors for their adverse motor control and severe slipping should be the highest priority in fall prevention process. Previous studies have suggested that muscle synergies may be building blocks of the central nervous system in controlling motor tasks. Muscle synergies observed during slipping (‘post-slip-initiation synergies’ or ‘just briefly,’ ‘slipping muscle synergies’), may represent the fundamental blocks of the neural control during slipping. Hence, studying the differences in slipping muscle synergies of mild and severe slippers can potentially reveal the differences in their neural control and subsequently, indicate the responsible factors for the adverse post-slip response in severe slippers. Even though the slipping muscle synergies have been investigated before, it still remains unclear on how the slip severity is associated with the slipping muscle synergies. More importantly, muscle synergies can be interpreted not only as neural blocks but also as physical sub-tasks of the main motor task. Hence, studying the differences of slipping synergies of mild and severe slippers would reveal the discrepancies in sub-tasks of their post-slip response. These discrepancies help pinpoint the malfunctioning sub-function associated with inadequate motor response seen in severe slippers. Twenty healthy subjects were recruited and underwent an unexpected slip (to extract their slipping synergies). Subjects were classified into mild and severe slippers based on their Peak Heel Speed. An independent t-test revealed several significant inter-group differences for muscle synergies of mild and severe slippers indicating

  18. Cascadia slow slip events and earthquake initiation theories: Hazards research with Plate Boundary Observatory geodetic data (Invited)

    Science.gov (United States)

    Roeloffs, E. A.; Beeler, N. M.

    2013-12-01

    The relationship of transient slow slip events (SSEs) to great earthquakes is a global focus of intense and critical hazards research. Plate Boundary Observatory (PBO) GPS and borehole strainmeter (BSM) networks in the Cascadia forearc provide detailed data that can be compared with simulations predicting how SSEs might evolve as a great earthquake approaches. Cascadia SSEs represent aseismic slip of a few cm in the direction of plate convergence over a period of days or weeks, in a depth range down-dip from the locked zone expected to generate the next great Cascadia subduction earthquake. During an SSE, shear stress borne in the SSE depth range is transferred up-dip at an above-background loading rate. If shear stress on the locked zone is continually accumulating, the daily probability of reaching a threshold failure stress is elevated during an SSE . Alternatively, if dynamic instability is due to rate-weakening fault strength, then SSEs still promote earthquake initiation, but that initiation may be delayed until after the SSE ends, and short-duration SSEs may have negligible effect. In some numerical simulations, great earthquakes could nucleate in the SSE depth range, where effective pressure is assumed to be low. Certain models predict that successive SSEs will slip to increasingly shallower depths, eventually encountering higher effective stress where shear heating can destabilize slip and lead to dynamic rupture. PBO GPS stations have recorded surface deformation from SSEs since inception in 2003; borehole strainmeters (BSMs) have recorded SSE strain signals since 2007. GPS and seismic tremor data show that SSEs reoccur all along the Cascadia subduction zone. An SSE is in progress somewhere in Cascadia much of the time, so the short-term probability increase warranted by a typical SSE is presumably low. We could, however, detect differences among successive SSEs and use criteria informed by the models described above to judge whether a distinctive SSE

  19. Earthquake source properties from instrumented laboratory stick-slip

    Science.gov (United States)

    Kilgore, Brian D.; McGarr, Arthur F.; Beeler, Nicholas M.; Lockner, David A.; Thomas, Marion Y.; Mitchell, Thomas M.; Bhat, Harsha S.

    2017-01-01

    Stick-slip experiments were performed to determine the influence of the testing apparatus on source properties, develop methods to relate stick-slip to natural earthquakes and examine the hypothesis of McGarr [2012] that the product of stiffness, k, and slip duration, Δt, is scale-independent and the same order as for earthquakes. The experiments use the double-direct shear geometry, Sierra White granite at 2 MPa normal stress and a remote slip rate of 0.2 µm/sec. To determine apparatus effects, disc springs were added to the loading column to vary k. Duration, slip, slip rate, and stress drop decrease with increasing k, consistent with a spring-block slider model. However, neither for the data nor model is kΔt constant; this results from varying stiffness at fixed scale.In contrast, additional analysis of laboratory stick-slip studies from a range of standard testing apparatuses is consistent with McGarr's hypothesis. kΔt is scale-independent, similar to that of earthquakes, equivalent to the ratio of static stress drop to average slip velocity, and similar to the ratio of shear modulus to wavespeed of rock. These properties result from conducting experiments over a range of sample sizes, using rock samples with the same elastic properties as the Earth, and scale-independent design practices.

  20. Earthquake slip weakening and asperities explained by thermal pressurization.

    Science.gov (United States)

    Wibberley, Christopher A J; Shimamoto, Toshihiko

    2005-08-04

    An earthquake occurs when a fault weakens during the early portion of its slip at a faster rate than the release of tectonic stress driving the fault motion. This slip weakening occurs over a critical distance, D(c). Understanding the controls on D(c) in nature is severely limited, however, because the physical mechanism of weakening is unconstrained. Conventional friction experiments, typically conducted at slow slip rates and small displacements, have obtained D(c) values that are orders of magnitude lower than values estimated from modelling seismological data for natural earthquakes. Here we present data on fluid transport properties of slip zone rocks and on the slip zone width in the centre of the Median Tectonic Line fault zone, Japan. We show that the discrepancy between laboratory and seismological results can be resolved if thermal pressurization of the pore fluid is the slip-weakening mechanism. Our analysis indicates that a planar fault segment with an impermeable and narrow slip zone will become very unstable during slip and is likely to be the site of a seismic asperity.

  1. Net Locality

    DEFF Research Database (Denmark)

    de Souza e Silva, Adriana Araujo; Gordon, Eric

    Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

  2. Net Neutrality

    DEFF Research Database (Denmark)

    Savin, Andrej

    2017-01-01

    Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else.......Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else....

  3. Reduction of Net Sulfide Production Rate by Nitrate in Wastewater Bioreactors. Kinetics and Changes in the Microbial Community

    DEFF Research Database (Denmark)

    Villahermosa, Desiree; Corzo, Alfonso; Gonzalez, J M

    2013-01-01

    Nitrate addition stimulated sulfide oxidation by increasing the activity of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), decreasing the concentration of dissolved H2S in the water phase and, consequently, its release to the atmosphere of a pilot-scale anaerobic bioreactor. The effect...... of four different concentrations of nitrate (0.12, 0.24, 0.50, and 1.00 mM) was investigated for a period of 3 days in relation to sulfide concentration in two bioreactors set up at Guadalete wastewater treatment plant (Jerez de la Frontera, Spain). Physicochemical variables were measured in water and air......, and the activity of bacteria implicated in the sulfur and nitrogen cycles was analyzed in the biofilms and in the water phase of the bioreactors. Biofilms were a net source of sulfide for the water and gas phases (7.22 ± 5.3 μmol s−1) in the absence of nitrate dosing. Addition of nitrate resulted in a quick...

  4. [Slipped capital femoral epiphysis].

    Science.gov (United States)

    Martínez-Álvarez, S; Martínez-González, C; Miranda Gorozarri, C; Abril, J C; Epeldegui, T

    2012-01-01

    Slipped capital femoral epiphysis (SCFE) is characterized by displacement of the capital femoral epiphysis from the metaphysis through the physis. The term is confusing, because the metaphysis moves upward and outward while the epiphysis remains in the acetabulum. The SCFE is considered stable when the child is able to walk with or without crutches, and it is considered unstable when the child cannot walk with or without crutches. Patients with SCFE present with pain in the groin, knee and limp. The current treatment of stable SCFE is in situ stabilization with a single screw. Copyright © 2012 SECOT. Published by Elsevier Espana. All rights reserved.

  5. Slips of the Pun

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    ’ at the same time, the second one of which gets told as a result of a simple slip of a pun. If one story of the poem is the poet-speaker’s hermeneutic quest for the possible meaningfulness of a past love affair, the other – somewhat less conspicuously – introduces his attempt to remember and recover the bodily...... relationship with them if one extends Ashbery’s playing with word to what goes one in the reader’s interpretive act? Ashbery’s friend and fellow poet Kenneth Koch once said of the former’s poetry that “it wants to go to bed with you”....

  6. Slips of the Pun

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    2008-01-01

    ’ at the same time, the second one of which gets told as a result of a simple slip of a pun. If one story of the poem is the poet-speaker’s hermeneutic quest for the possible meaningfulness of a past love affair, the other – somewhat less conspicuously – introduces his attempt to remember and recover the bodily...... relationship with them if one extends Ashbery’s playing with word to what goes one in the reader’s interpretive act? Ashbery’s friend and fellow poet Kenneth Koch once said of the former’s poetry that “it wants to go to bed with you”....

  7. Children of the 21st century: slipping through the net.

    Science.gov (United States)

    Williams, Jane; Holmes, Colin

    This article briefly explores the literature focusing on early childhood development, parenting and the provision of health services to young families. It highlights a number of reasons why some children with subtle developmental difficulties are not identified until school age. Relevant to child health nurses are: a changing focus on early childhood health issues; low repeat attendance at child health clinics, and the reluctance of parents to seek assistance; the impact of socio-economic status, cultural and ideological influences; the challenges presented in using complex screening tools; the difficulty in detecting subtle developmental problems; the lack of involvement of parents in decision-making; and, the reluctance of both professionals and parents to 'label' children. Drawing attention to these issues is essential for child health nurses who have the opportunity to provide effective and timely assistance to families and young children.

  8. Pressures on safety net access: the level of managed care penetration and uninsurance rate in a community

    National Research Council Canada - National Science Library

    Cunningham, P J

    1999-01-01

    To examine the effects of managed care penetration and the uninsurance rate in an area on access to care of low-income uninsured persons and to compare differences in access between low-income insured...

  9. The HLA-net GENE[RATE] pipeline for effective HLA data analysis and its application to 145 population samples from Europe and neighbouring areas.

    Science.gov (United States)

    Nunes, J M; Buhler, S; Roessli, D; Sanchez-Mazas, A

    2014-05-01

    In this review, we present for the first time an integrated version of the Gene[rate] computer tools which have been developed during the last 5 years to analyse human leukocyte antigen (HLA) data in human populations, as well as the results of their application to a large dataset of 145 HLA-typed population samples from Europe and its two neighbouring areas, North Africa and West Asia, now forming part of the Gene[va] database. All these computer tools and genetic data are, from now, publicly available through a newly designed bioinformatics platform, HLA-net, here presented as a main achievement of the HLA-NET scientific programme. The Gene[rate] pipeline offers user-friendly computer tools to estimate allele and haplotype frequencies, to test Hardy-Weinberg equilibrium (HWE), selective neutrality and linkage disequilibrium, to recode HLA data, to convert file formats, to display population frequencies of chosen alleles and haplotypes in selected geographic regions, and to perform genetic comparisons among chosen sets of population samples, including new data provided by the user. Both numerical and graphical outputs are generated, the latter being highly explicit and of publication quality. All these analyses can be performed on the pipeline after scrupulous validation of the population sample's characterisation and HLA typing reporting according to HLA-NET recommendations. The Gene[va] database offers direct access to the HLA-A, -B, -C, -DQA1, -DQB1, -DRB1 and -DPB1 frequencies and summary statistics of 145 population samples having successfully passed these HLA-NET 'filters', and representing three European subregions (South-East, North-East and Central-West Europe) and two neighbouring areas (North Africa, as far as Sudan, and West Asia, as far as South India). The analysis of these data, summarized in this review, shows a substantial genetic variation at the regional level in this continental area. These results have main implications for population genetics

  10. Tingkat Insidensi Malaria di Wilayah Pemanasan Kelambu Berinsektisida Tahan Lama dan Wilayah Kontrol (MALARIA INCIDENCE RATE OF HEAT ASSISTED REGENERATION LONG LASTING INSECTICIDAL NETS AREA AND CONTROL

    Directory of Open Access Journals (Sweden)

    Etih Sudarnika

    2012-03-01

    Full Text Available Long lasting insecticidal nets (LLIN is one effective way to prevent malaria. Permethrin treatedLLIN is one type of LLIN which is recommended by WHO. Several studies have shown that these types ofLLIN requiring heat assisted regeneration after washing to enhance the biological activity of insecticidethat contained in the LLIN fibers. This study aimed to compare the incidence rates of malaria in childrenunder five years old who live in the intervention area (where the heat assisted regeneration on LLIN afterwashing was applied and control area (where the heat assisted regeneration on LLIN after washing wasnot applied. Data of malaria cases was collected from laboratory log book at all health centers in BangkaDistrict, in the period of June June 2007 until July 2008. Data were analyzed with Poisson regressionmodels. The results showed that the incidence rate of malaria in children under five years old was notsignificantly different between the treatment and control areas.

  11. Stick-Slip Instabilities for Interfacial Chemical Bond-Induced Friction at the Nanoscale.

    Science.gov (United States)

    Tian, Kaiwen; Gosvami, Nitya N; Goldsby, David L; Carpick, Robert W

    2017-12-08

    Earthquakes are generally caused by unstable stick-slip motion of faults. This stick-slip phenomenon, along with other frictional properties of materials at the macroscale, is well-described by empirical rate and state friction (RSF) laws. Here we study stick-slip behavior for nanoscale single-asperity silica-silica contacts in atomic force microscopy experiments. The stick-slip is quasiperiodic, and both the amplitude and spatial period of stick-slip increase with normal load and decrease with the loading point (i.e., scanning) velocity. The peak force prior to each slip increases with the temporal period logarithmically, and decreases with velocity logarithmically, consistent with stick-slip behavior at the macroscale. However, unlike macroscale behavior, the minimum force after each slip is independent of velocity. The temporal period scales with velocity in a nearly power law fashion with an exponent between -1 and -2, similar to macroscale behavior. With increasing velocity, stick-slip behavior transitions into steady sliding. In the transition regime between stick-slip and smooth sliding, some slip events exhibit only partial force drops. The results are interpreted in the context of interfacial chemical bond formation and rate effects previously identified for nanoscale contacts. These results contribute to a physical picture of interfacial chemical bond-induced stick-slip, and further establish RSF laws at the nanoscale.

  12. Contemporary deformation, kinematics, and dynamics of the Yellowstone hotspot and western U.S. interior from GPS, fault slip rates, and earthquake data

    Science.gov (United States)

    Puskas, Christine Maria

    2009-12-01

    Contemporary deformation of the 800-km long, 17-Ma Yellowstone-Snake River Plain (YSRP) volcano-tectonic system was measured by the Global Positioning System (GPS) and other geologic data and incorporated into regional kinematic and dynamic models. Postseismic relaxation effects from M>7 western U.S. earthquakes were evaluated and corrected for in the kinematic models. Data from 140 benchmarks observed during seven major GPS field experiments between 1987 and 2003 were processed to obtain deformation rates of the Yellowstone caldera and eastern Snake River Plain (ESRP). Comparison of seismic and geodetic moment rates indicated that notable caldera uplift and subsidence was primarily aseismic and probably driven by accumulation and migration of fluids derived from the mid-crustal Yellowstone magma reservoir. Southwest intraplate extension of up to 4.3 +/- 0.2 mm/yr was observed across the Yellowstone Plateau, while the ESRP experienced contraction and relatively uniform southwest motion of 2.1 +/- 0.2 mm/yr. The YSRP GPS-derived velocities were combined with ˜2500 velocities from multiple studies in western U.S. kinematic models. One microplate block model and one finite element model were determined to assess YSRP motion in an intraplate tectonic framework and resolve regional clockwise rotation of deformation. Both models found Yellowstone hotspot volcanism modifies the GPE. The YSRP was found to have a lower GPE than the surrounding high mountains associated with the hotspot swell, from which it was inferred that hotspot volcanism is a mechanism for dissipating excess GPE. The high elevation of the swell effectively reoriented tensional stress axes toward a southwest direction, driving southwest motion of the YSRP. The hotspot-derived stresses, when combined with gravitational collapse of the Basin-Range and boundary stresses from Pacific-North America-Juan de Fuca plate interactions, accounts for the observed rotation of the western U.S. deformation field.

  13. RESTful NET

    CERN Document Server

    Flanders, Jon

    2008-01-01

    RESTful .NET is the first book that teaches Windows developers to build RESTful web services using the latest Microsoft tools. Written by Windows Communication Foundation (WFC) expert Jon Flanders, this hands-on tutorial demonstrates how you can use WCF and other components of the .NET 3.5 Framework to build, deploy and use REST-based web services in a variety of application scenarios. RESTful architecture offers a simpler approach to building web services than SOAP, SOA, and the cumbersome WS- stack. And WCF has proven to be a flexible technology for building distributed systems not necessa

  14. A new method to estimate photosynthetic parameters through net assimilation rate-intercellular space CO2 concentration (A-Ci ) curve and chlorophyll fluorescence measurements.

    Science.gov (United States)

    Moualeu-Ngangue, Dany P; Chen, Tsu-Wei; Stützel, Hartmut

    2017-02-01

    Gas exchange (GE) and chlorophyll fluorescence (CF) measurements are widely used to noninvasively study photosynthetic parameters, for example the rates of maximum Rubisco carboxylation (Vcmax ), electron transport rate (J), daytime respiration (Rd ) and mesophyll conductance (gm ). Existing methods for fitting GE data (net assimilation rate-intercellular space CO2 concentration (A-Ci ) curve) are based on two assumptions: gm is unvaried with CO2 concentration in the intercellular space (Ci ); and light absorption (α) and the proportion of quanta absorbed by photosystem II (β) are constant in the data set. These may result in significant bias in estimating photosynthetic parameters. To avoid the above-mentioned hypotheses, we present a new method for fitting A-Ci curves and CF data simultaneously. This method was applied to a data set obtained from cucumber (Cucumis sativus) leaves of various leaf ages and grown under eight different light conditions. The new method had significantly lower root mean square error and a lower rate of failures compared with previously published methods (6.72% versus 24.1%, respectively) and the effect of light conditions on Vcmax and J was better observed. Furthermore, the new method allows the estimation of a new parameter, the fraction of incoming irradiance harvested by photosystem II, and the dependence of gm on Ci . © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  15. NetSig

    DEFF Research Database (Denmark)

    Horn, Heiko; Lawrence, Michael S; Chouinard, Candace R

    2018-01-01

    Methods that integrate molecular network information and tumor genome data could complement gene-based statistical tests to identify likely new cancer genes; but such approaches are challenging to validate at scale, and their predictive value remains unclear. We developed a robust statistic (Net......Sig) that integrates protein interaction networks with data from 4,742 tumor exomes. NetSig can accurately classify known driver genes in 60% of tested tumor types and predicts 62 new driver candidates. Using a quantitative experimental framework to determine in vivo tumorigenic potential in mice, we found that Net......Sig candidates induce tumors at rates that are comparable to those of known oncogenes and are ten-fold higher than those of random genes. By reanalyzing nine tumor-inducing NetSig candidates in 242 patients with oncogene-negative lung adenocarcinomas, we find that two (AKT2 and TFDP2) are significantly amplified...

  16. [Slip casting of stainless steel powder (author's transl)].

    Science.gov (United States)

    Okawa, S; Ota, M; Kondo, S

    1976-01-01

    Slip casting of stainless steel powder (AISI type 316 L) was investigated as means of forming medical and dental porous restorations. This research was undertaken to evaluate the effects of the particle size and aging of casting slip and firing conditions. Bulk density was used as a measure of the degree of sintering. Water contents of casting bodies decreased with the particle size and its casting rates, bulk densities and bending strengths increased. Aging of slip decreased casting rates, water contents and bending strengths of the casts. The bulk densities of the sintered stainless steel increased with sintering time and temperature. The porosities of the materials decreased with the particle size and the elevating temperature. The bending strengths of the materials increased sharply with the decreasing particle size. The optical micrographs did not always show the uniform elimination of pores in the sintered. Aging of slip increased a little the bulk densities of the materials and decreased the porosity and the bending strength.

  17. A prospective study of floor surface, shoes, floor cleaning and slipping in US limited-service restaurant workers.

    Science.gov (United States)

    Verma, Santosh K; Chang, Wen Ruey; Courtney, Theodore K; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Mittleman, Murray A; Ware, James H; Perry, Melissa J

    2011-04-01

    Slips and falls are a leading cause of injury at work. Few studies, however, have systematically examined risk factors of slipping outside the laboratory environment. This study examined the association between floor surface characteristics, slip-resistant shoes, floor cleaning frequency and the risk of slipping in limited-service restaurant workers. 475 workers from 36 limited-service restaurants from three major chains in six states in the USA were recruited to participate in a prospective cohort study of workplace slipping. Kitchen floor surface roughness and coefficient of friction (COF) were measured in eight working areas and then averaged within each restaurant. The use of slip-resistant shoes was determined by examining the participant's shoes and noting the presence of a 'slip-resistant' marking on the sole. Restaurant managers reported the frequency of daily kitchen floor cleaning. Participants reported their slip experience and work hours weekly for up to 12 weeks. The survey materials were made available in three languages: English, Spanish and Portuguese. The associations between rate of slipping and risk factors were assessed using a multivariable negative binomial generalised estimating equation model. The mean of individual slipping rate varied among the restaurants from 0.02 to 2.49 slips per 40 work hours. After adjusting for age, gender, BMI, education, primary language, job tenure and restaurant chain, the use of slip-resistant shoes was associated with a 54% reduction in the reported rate of slipping (95% CI 37% to 64%), and the rate of slipping decreased by 21% (95% CI 5% to 34%) for each 0.1 increase in the mean kitchen COF. Increasing floor cleaning frequency was significantly associated with a decreasing rate of slipping when considered in isolation but not after statistical adjustment for other factors. These results provide support for the use of slip-resistant shoes and measures to increase COF as preventive interventions to reduce slips

  18. Petri Nets

    Indian Academy of Sciences (India)

    Associate Professor of. Computer Science and. Automation at the Indian. Institute of Science,. Bangalore. His research interests are broadly in the areas of stochastic modeling and scheduling methodologies for future factories; and object oriented modeling. GENERAL I ARTICLE. Petri Nets. 1. Overview and Foundations.

  19. Petri Nets

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 8. Petri Nets - Overview and Foundations. Y Narahari. General Article Volume 4 Issue 8 August 1999 pp ... Author Affiliations. Y Narahari1. Department ot Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India.

  20. Valgus slipped capital femoral epiphysis with contralateral pre-slip.

    Science.gov (United States)

    Amiraian, Dana E; Sarwar, Zahir; Bireley, William R; Moran, Elizabeth

    2017-09-01

    Slipped capital femoral epiphysis (SCFE) is a common hip disorder in older children and adolescents, classically with medial and posterior slippage of the proximal femoral epiphysis. However, valgus SCFE is a very rare entity, where the proximal femoral epiphysis slips laterally and posteriorly. To our knowledge, valgus SCFE with magnetic resonance imaging (MRI) features of contralateral pre-slip has not yet been reported. We present a case of a 9 year old girl with symptomatic valgus SCFE on the left and asymptomatic contralateral pre-slip on the right with concurrent radiographic, sonographic, and MRI findings. Such findings include bilateral coxa valga, radiographic irregularity of the left proximal femoral physis, bilateral hip effusions, abnormal MRI signal and enhancement about both proximal femoral physes, and minimal posterolateral slippage of the left proximal femoral epiphysis. We highlight these pertinent imaging findings and review the importance of accurately diagnosing this rare entity for appropriate surgical management.

  1. Effects of nitrogen application rates on net annual global warming potential and greenhouse gas intensity in double-rice cropping systems of the Southern China.

    Science.gov (United States)

    Chen, Zhongdu; Chen, Fu; Zhang, Hailin; Liu, Shengli

    2016-12-01

    The net global warming potential (NGWP) and net greenhouse gas intensity (NGHGI) of double-rice cropping systems are not well documented. We measured the NGWP and NGHGI including soil organic carbon (SOC) change and indirect emissions (IE) from double-crop rice fields with fertilizing systems in Southern China. These experiments with three different nitrogen (N) application rates since 2012 are as follows: 165 kgN ha -1 for early rice and 225 kgN ha -1 for late rice (N1), which was the local N application rates as the control; 135 kgN ha -1 for early rice and 180 kgN ha -1 for late rice (N2, 20 % reduction); and 105 kgN ha -1 for early rice and 135 kgN ha -1 for late rice (N3, 40 % reduction). Results showed that yields increased with the increase of N application rate, but without significant difference between N1 and N2 plots. Annual SOC sequestration rate under N1 was estimated to be 1.15 MgC ha -1  year -1 , which was higher than those under other fertilizing systems. Higher N application tended to increase CH 4 emissions during the flooded rice season and significantly increased N 2 O emissions from drained soils during the nonrice season, ranking as N1 > N2 > N3 with significant difference (P < 0.05). Two-year average IE has a huge contribution to GHG emissions mainly coming from the higher N inputs in the double-rice cropping system. Reducing N fertilizer usage can effectively decrease the NGWP and NGHGI in the double-rice cropping system, with the lowest NGHGI obtained in the N2 plot (0.99 kg CO 2 -eq kg -1 yield year -1 ). The results suggested that agricultural economic viability and GHG mitigation can be simultaneously achieved by properly reducing N fertilizer application in double-rice cropping systems.

  2. Vertically bounded double diffusive convection in the fingering regime: comparing no-slip vs free-slip boundary conditions

    CERN Document Server

    Yang, Yantao; Lohse, Detlef

    2016-01-01

    Vertically bounded fingering double diffusive convection (DDC) is numerically investigated, focusing on the influences of different velocity boundary conditions, i.e. the no-slip condition which is inevitable in the lab-scale experimental research, and the free-slip condition which is an approximation for the interfaces in many natural environments, such as the oceans. For both boundary conditions the flow is dominated by fingers and the global responses follow the same scaling laws, with enhanced prefactors for the free-slip cases. Therefore, the laboratory experiments with the no-slip boundaries serve as a good model for the finger layers in the ocean. Moreover, in the free-slip case although the tangential shear stress is eliminated at the boundaries, the local dissipation rate in the near-wall region may exceed the value found in the no-slip cases, which is caused by the stronger vertical motions of fingers and sheet structures near the free-slip boundaries. This counter intuitive result might be relevant...

  3. Slips of the Pun

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    2008-01-01

    of view. On the one hand, it obviously raises the question of signification and interpretation. On the other hand, it seems to pun on the double meaning of the word ‘sense’, thus signifying not only ‘meaning’, but also ‘sensuality’. In this way, Ashbery’s poem turns out to read as ‘two different stories...... are just as much about how their punning is a mere suggestive play with words, having no determinate, let alone finally determinable sense – sexual or otherwise. Incidentally, Ashbery’s poetic ‘I’ in his long poem “A Wave” (1984) asks: “Were we making sense?” The question is interesting from two points......’ at the same time, the second one of which gets told as a result of a simple slip of a pun. If one story of the poem is the poet-speaker’s hermeneutic quest for the possible meaningfulness of a past love affair, the other – somewhat less conspicuously – introduces his attempt to remember and recover the bodily...

  4. Long-term slip deficit and the forecasting of slip in future earthquakes

    Science.gov (United States)

    McCloskey, John; NicBhloscaidh, Mairead; Simao, Nuno

    2014-05-01

    In the last decade a series of devastating earthquakes have between them killed more than three-quarters of a million people. None of the events were formally forecast and have been repeatedly referred to a seismological 'surprises'. Here we argue that while earthquakes within the wide swath of diffuse deformation comprising the Alpine-Himalayan belt pose a set of particularly difficult set of challenges, earthquakes which are driven by high strain-rates at plate boundaries and which have relatively short nominal recurrence times might be forecast if the data exists to perform long-term slip deficit modelling and stress reconstruction. We show that two instrumentally recorded event on the Sumatran margin in 2007 and 2010 occurred in regions of high slip deficit identified by reconstruction of slip in historical earthquakes in 1797 and 1833 under the Mentawai Islands using more than 200 years of geodetic data recorded in the stratigraphy of coral micro-atolls growing there. In the presentation we will describe the data and a new Bayesian-Monte Carlo slip reconstruction technique. The technique is based on the stochastic forward modelling of many slip distributions each using the same set of elastic Green's functions to estimate, by superposition of contributions from each fault cell, the vertical displacement at the coral locations resulting from each simulated event. Every solution, weighted by its goodness of fit to the data, is added to a stack whose final values contain an estimate of the most likely distribution of slip in the historical earthquakes. Further, we estimate the Kullback-Liebler divergence over the fault area providing a non-arbitrary assessment of the spatial distribution of information gain, identifying regions of low- and high- model confidence. We then model the long-term slip deficit on the megathrust assuming a zero of stress immediately after the 1652 Mentawai Islands earthquake. We use the resulting slip deficit field to compute the entire

  5. Slip of a one-body dynamical spring-slider model in the presence of slip-weakening friction and viscosity

    Directory of Open Access Journals (Sweden)

    Jeen-Hwa Wang

    2016-11-01

    Full Text Available This study is focused on analytic study at small displacements and numerical simulations of slip of a one-body dynamical slider-slider model in the presence of slip-weakening friction and viscosity. Analytic results with numerical computations show that the displacement of the slider is controlled by the decreasing rate, [gamma], of friction force with slip and viscosity, [eta], of fault-zone material. The natural period of the system with slip-weakening friction and viscosity is longer than that of the system without the two factors. There is a solution regime for [eta] and [gamma] to make the slider slip steadily without strong attenuation. The viscous effect is stronger than the frictional effect. Meanwhile, a change of [eta] results in a larger effect on the slip of the slider than a change of [gamma]. Numerical simulations are made for a one-body dynamical slider-slider model in the presence of three slip-weakening friction laws, i.e., the thermal-pressurization (TP friction law, the softening-hardening (SH friction law, and a simple slip-weakening (SW friction law, and viscosity. Results show that slip-weakening friction and viscosity remarkably affect slip of the slider. The TP and SW friction laws cause very similar results. The results caused by the SH friction law are quite different from those by the other two. For the cases in study, the fixed points are not an attractor.

  6. Workers' experience of slipping in U.S. limited-service restaurants.

    Science.gov (United States)

    Verma, Santosh K; Chang, Wen-Ruey; Courtney, Theodore K; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Mittleman, Murray A; Perry, Melissa J

    2010-09-01

    The leading cause of injuries among restaurant workers is same-level falls, a significant proportion of which result from slipping. This study examines the experience of limited-service restaurant workers with slipping, their use of slip-resistant shoes, and their floor-cleaning practices. A total of 475 workers from 36 limited-service restaurants in six U.S. states participated in a 12-week prospective cohort study on slipping in the workplace. At baseline, participants completed a survey that gathered information about their demographics, perceptions of floor slipperiness, use of slip-resistant shoes, floor cleaning practices, and number of slips experienced in the previous 4 weeks. During the subsequent 12 weeks, participants reported their slip experience weekly. Restaurant managers reported kitchen floor cleaning protocols and shoe policies. The overall rate of slipping during the 12 weeks of the prospective study was 0.44 slips per 40 work hours. The mean of the individual rate of slipping varied among the restaurants from 0.02 to 2.49 slips per 40 work hours, a rate ratio of more than 100 among the restaurants with the highest and the lowest rate of slipping. Such a large variation, which is unlikely due to chance alone (p restaurants are better able to control slipping than others. The highest numbers of slips were reported in the sink and fryer areas, which were also identified by restaurant workers as being the most slippery. Liquid and grease were reported as floor contaminants in over 70% of the slips. In restaurants where slip-resistant shoes were provided by the employer, 91% of participants wore them; whereas if they were neither provided nor encouraged, only 53.5% wore them (p restaurants, however, 62% of the participants who were responsible for cleaning floors reported using hot/warm water, thus violating the manufacturer's cold water floor cleaning protocol. These findings suggest that focused prevention efforts based on practices from

  7. NETS FOR PEACH PROTECTED CULTIVATION

    Directory of Open Access Journals (Sweden)

    Evelia Schettini

    2012-06-01

    Full Text Available The aim of this paper was to investigate the radiometric properties of coloured nets used to protect a peach cultivation. The modifications of the solar spectral distribution, mainly in the R and FR wavelength band, influence plant photomorphogenesis by means of the phytochrome and cryptochrome. The phytochrome response is characterized in terms of radiation rate in the red wavelengths (R, 600-700 nm to that in the farred radiation (FR, 700-800 nm, i.e. the R/FR ratio. The effects of the blue radiation (B, 400-500 nm is investigated by the ratio between the blue radiation and the far-red radiation, i.e. the B/FR ratio. A BLUE net, a RED net, a YELLOW net, a PEARL net, a GREY net and a NEUTRAL net were tested in Bari (Italy, latitude 41° 05’ N. Peach trees were located in pots inside the greenhouses and in open field. The growth of the trees cultivated in open field was lower in comparison to the growth of the trees grown under the nets. The RED, PEARL, YELLOW and GREY nets increased the growth of the trees more than the other nets. The nets positively influenced the fruit characteristics, such as fruit weight and flesh firmness.

  8. Direct chemical measurement of DNA synthesis and net rates of differentiation of rat lens epithelial cells in vivo: applied to the selenium cataract.

    Science.gov (United States)

    Cenedella, R J

    1987-05-01

    This report describes a direct chemical method for rapidly estimating DNA synthesis and net rates of epithelial cell differentiation in the ocular lens in vivo. DNA synthesis in the lens of control and selenium-treated rats (12- or 13 days of age) was estimated by chemically isolating and measuring trichloroacetic acid (TCA)-insoluble 3H from the lens following injection of [3H]thymidine. Labeled substrate for DNA synthesis peaked in the lens at 1 hr after injection, decreased markedly by the third hour and was essentially gone by hour 12. Synthesis of labeled DNA in the lens was largely complete by about 3 hr. The [3H]DNA content of the whole lens, measured as TCA-insoluble 3H, remained constant for at least 4 months. The distribution of labeled epithelial cells between the epithelial-cell layer and fiber-cell mass was followed for up to 1 month after injection by measuring the ratio of [3H]DNA in the capsule (epithelial-cell layer) to lens body. Between days 2-3 and day 14 after injection, the ratio of [3H]DNA in the epithelial-cell layer to lens fiber cells decreased linearly in a semilogarithmic plot of the ratio vs. time; i.e. the rate of change of the ratio followed first-order kinetics. Thus, the rate constant (k) for the rate of change in the ratio of [3H]DNA in the capsule layer to lens body can provide an estimate of the percentage of the labeled epithelial cells which leave the capsule per day through differentiation into fiber cells. An apparent rate constant of 0.27 day-1 was estimated from the mean of five experiments; i.e. 27% of labeled epithelial cells were differentiating into cortical fiber cells per day. Therefore, about 70% of the germinative epithelial cells would be replaced every 4 days in these rats. This value is in good agreement with results of studies using autoradiographic technics. The selenium cataract is reported to involve rapid damage to lens epithelial cells. Incorporation of [3H]thymidine into DNA was decreased by at least 60

  9. Molecular Dynamics Simulations of Slip on Curved Surfaces

    Directory of Open Access Journals (Sweden)

    Ross D.A.

    2016-07-01

    Full Text Available We present Molecular Dynamics (MD simulations of liquid water confined within nanoscale geometries, including slit-like and cylindrical graphitic pores. These equilibrium results are used for calculating friction coefficients, which in turn can be used to calculate slip lengths. The slip length is a material property independent of the fluid flow rate. It is therefore a better quantity for study than the fluid velocity at the wall, also known as the slip velocity. Once the slip length has been found as a function of surface curvature, it can be used to parameterise Lattice Boltzmann (LB simulations. These larger scale simulations are able to tell us about how fluid transport is affected by slip in complex geometries; not just limited to single pores. Applications include flow and transport in nano-porous engine valve deposits and gas shales. The friction coefficient is found to be a function of curvature and is higher for fluid on convex surfaces and lower for concave surfaces. Both concave and convex surfaces approach the same value of the friction coefficient, which is constant above some critical radius of curvature, here found to be 7.4 ± 2.9 nm. The constant value of the friction coefficient is 10,000 ± 600 kg m−2 s−1, which is equivalent to a slip length of approximately 67 ± 4 nm.

  10. Measurement of Newtonian fluid slip using a torsional ultrasonic oscillator

    Science.gov (United States)

    Willmott, G. R.; Tallon, J. L.

    2007-12-01

    The composite torsional ultrasonic oscillator, a versatile experimental system, can be used to investigate slip of a Newtonian fluid at a smooth surface. A rigorous analysis of slip-dependent damping for the oscillator is presented. Initially, the phenomenon of finite surface slip and the slip length are considered for a half space of Newtonian fluid in contact with a smooth, oscillating solid surface. Definitions are reconsidered and clarified in light of inconsistencies in the literature. We point out that, in general oscillating flows, Navier’s slip length b is a complex number. An intuitive velocity discontinuity parameter of unrestricted phase is used to describe the effect of slip on measurement of viscous shear damping. The analysis is applied to the composite oscillator, and preliminary experimental work for a 40 kHz oscillator is presented. The nonslip boundary condition has been verified for a hydrophobic surface in water to within ˜60nm of |b|=0nm . Experiments were carried out at shear rate amplitudes between 230 and 6800s-1 , corresponding to linear displacement amplitudes between 3.2 and 96 nm.

  11. Parametric Net Influx Rate Images of68Ga-DOTATOC and68Ga-DOTATATE: Quantitative Accuracy and Improved Image Contrast.

    Science.gov (United States)

    Ilan, Ezgi; Sandström, Mattias; Velikyan, Irina; Sundin, Anders; Eriksson, Barbro; Lubberink, Mark

    2017-05-01

    68 Ga-DOTATOC and 68 Ga-DOTATATE are radiolabeled somatostatin analogs used for the diagnosis of somatostatin receptor-expressing neuroendocrine tumors (NETs), and SUV measurements are suggested for treatment monitoring. However, changes in net influx rate ( K i ) may better reflect treatment effects than those of the SUV, and accordingly there is a need to compute parametric images showing K i at the voxel level. The aim of this study was to evaluate parametric methods for computation of parametric K i images by comparison to volume of interest (VOI)-based methods and to assess image contrast in terms of tumor-to-liver ratio. Methods: Ten patients with metastatic NETs underwent a 45-min dynamic PET examination followed by whole-body PET/CT at 1 h after injection of 68 Ga-DOTATOC and 68 Ga-DOTATATE on consecutive days. Parametric K i images were computed using a basis function method (BFM) implementation of the 2-tissue-irreversible-compartment model and the Patlak method using a descending aorta image-derived input function, and mean tumor K i values were determined for 50% isocontour VOIs and compared with K i values based on nonlinear regression (NLR) of the whole-VOI time-activity curve. A subsample of healthy liver was delineated in the whole-body and K i images, and tumor-to-liver ratios were calculated to evaluate image contrast. Correlation ( R 2 ) and agreement between VOI-based and parametric K i values were assessed using regression and Bland-Altman analysis. Results: The R 2 between NLR-based and parametric image-based (BFM) tumor K i values was 0.98 (slope, 0.81) and 0.97 (slope, 0.88) for 68 Ga-DOTATOC and 68 Ga-DOTATATE, respectively. For Patlak analysis, the R 2 between NLR-based and parametric-based (Patlak) tumor K i was 0.95 (slope, 0.71) and 0.92 (slope, 0.74) for 68 Ga-DOTATOC and 68 Ga-DOTATATE, respectively. There was no bias between NLR and parametric-based K i values. Tumor-to-liver contrast was 1.6 and 2.0 times higher in the parametric

  12. Slip flow in graphene nanochannels

    DEFF Research Database (Denmark)

    . Kannam, Sridhar; Billy, Todd; Hansen, Jesper Schmidt

    2011-01-01

    We investigate the hydrodynamic boundary condition for simple nanofluidic systems such as argon and methane flowing in graphene nanochannels using equilibrium molecular dynamics simulations (EMD) in conjunction with our recently proposed method [J. S. Hansen, B. D. Todd, and P. J. Daivis, Phys. Rev....... E 84, 016313 (2011)10.1103/PhysRevE.84.016313]. We first calculate the fluid-graphene interfacial friction coefficient, from which we can predict the slip length and the average velocity of the first fluid layer close to the wall (referred to as the slip velocity). Using direct nonequilibrium...

  13. Slip length measurement using BBM

    Science.gov (United States)

    Ahmadzadegan, Adib; Snoeyink, Craig

    2015-11-01

    We will be presenting experimental characterizations of slip lengths of fluids in nano/micro channels. These channels are becoming increasingly important in sensor and separations applications. However, crucial questions still remain on the mechanisms that govern slip-length behavior. We used Bessel Beam microscopy (BBM), a novel super-resolution imaging system, in conjunction with TIRF system. These two, together led us to be able to do Particle Tracking Velocimetry with significantly higher accuracy than previously possible. We will be presenting results demonstrating the feasibility of this approach and advantages that make this method unique.

  14. Slip-Cast Superconductive Parts

    Science.gov (United States)

    Wise, Stephanie A.; Buckley, John D.; Vasquez, Peter; Buck, Gregory M.; Hicks, Lana P.; Hooker, Matthew W.; Taylor, Theodore D.

    1993-01-01

    Complex shapes fabricated without machining. Nonaqueous slip-casting technique used to form complexly shaped parts from high-temperature superconductive materials like YBa(2)Cu(3)O(7-delta). Such parts useful in motors, vibration dampers, and bearings. In process, organic solvent used as liquid medium. Ceramic molds made by lost-wax process used instead of plaster-of-paris molds, used in aqueous slip-casting but impervious to organic solvents and cannot drain away liquid medium. Organic-solvent-based castings do not stick to ceramic molds as they do to plaster molds.

  15. Analytical solutions for squeeze flow with partial wall slip

    DEFF Research Database (Denmark)

    Laun, HM; Rady, M; Hassager, Ole

    1999-01-01

    Squeeze flow between parallel plates of a purely viscous material is considered for small gaps both for a Newtonian and power law fluid with partial wall slip. The results for the squeeze force as a function of the squeezing speed reduce to the Stefan and Scott equations in the no slip limit...... if plotted versus 1/H. The slope of the straight line is equal to 6 upsilon(s) whereas the intersect with the ordinate yields the effective Newtonian rim shear rate to be converted into the true rim shear rate by means of the power law exponent. The advantage of the new technique is the separation of bulk...

  16. Analytical method for determining breakdown slip of an induction motor based on of five parameters

    Directory of Open Access Journals (Sweden)

    Petrović Nenad

    2014-01-01

    Full Text Available The paper proposes an explicite formula for determining the critical slip value of an induction squirel cage motor based upon five parameters. Three of these parameters - rated slip, rated and breakdown torque are known by catalogue data. Two missing parameters are the arbitrary slip between the rated and critical slip value and the corresponding torque value. These two parameters are to be experimentaly obtained. The breakdown torque value given by catalogue data is usually less accurate than the rated torque value. The proposed formula gives the possibility of analysing the error distribution of the critical slip value obtained from catalogue and measured data in comparison with the values obtained from the mechanical characteristic based on the physical parameters of an induction motor.

  17. Stick-slip instabilities in sheared granular flow: The role of friction and acoustic vibrations.

    Science.gov (United States)

    Lieou, Charles K C; Elbanna, Ahmed E; Langer, J S; Carlson, J M

    2015-08-01

    We propose a theory of shear flow in dense granular materials. A key ingredient of the theory is an effective temperature that determines how the material responds to external driving forces such as shear stresses and vibrations. We show that, within our model, friction between grains produces stick-slip behavior at intermediate shear rates, even if the material is rate strengthening at larger rates. In addition, externally generated acoustic vibrations alter the stick-slip amplitude, or suppress stick-slip altogether, depending on the pressure and shear rate. We construct a phase diagram that indicates the parameter regimes for which stick-slip occurs in the presence and absence of acoustic vibrations of a fixed amplitude and frequency. These results connect the microscopic physics to macroscopic dynamics and thus produce useful information about a variety of granular phenomena, including rupture and slip along earthquake faults, the remote triggering of instabilities, and the control of friction in material processing.

  18. Scaling of micro-slip in tangentially loaded rock contact

    Science.gov (United States)

    Grzemba, Birthe; Pohrt, Roman; Teidelt, Elena; Popov, Valentin L.

    2014-05-01

    A dry contact between randomly rough surfaces is examined which is loaded in normal and tangential direction. If the tangential load is below the friction force, no macroscopic tangential movement takes place. Nevertheless, some part of the contact area will be in sticking and some will be in sliding state depending on the local stress configuration. This effect will be called micro-slip. The maximum value of this micro-slip is reached when the last contacting spot goes into sliding state. The maximum micro-slip is a core characteristic of the contact problem. It appears in rock friction laws as a characteristic length parameter, which is often empirically determined. It can be interpreted as the characteristic size of micro-contacts appearing in rate-and-state friction theory (1). The scaling behavior of this characteristic length parameter is not yet clarified (2). It is of special interest for geophysical applications, where laboratory experiments and real systems differ in size by several orders of magnitude. In former works many suggestions have been made on the scaling context of this length parameter: surface roughness, total slip length, shear strain and system size ((1),(3),(4),(5)) are some of the proposed connected parameters. We recently presented a theoretical estimation of the maximum micro-slip for randomly rough surfaces, which is based on the iterrelation of the normal and tangential contact problem. Using recent finding concerning the normal contact problem of randomly rough surfaces (6) we were able to suggest a scaling law for the maximum micro-slip. It suggests a power-law scaling with the present normal force (7). A numerical contact model using the boundary element method was implemented for comparison, both results coincide perfectly. In addition we will present experiments with rock-rock contact in the preface of instable sliding. The set-up is a single-block slider model. From high resolution measurements, we were able to capture the micro-slip

  19. Routing Slips from the Computer

    Science.gov (United States)

    Blair, Joan

    1972-01-01

    To facilitate the routing of periodicals, a computerized system of printing and updating routing lists was designed to replace a manual one. A computer program generates a data base of staff routing choices and prints out routing slips for each periodical. (Author/NH)

  20. Shaker slip-plate adapter

    Science.gov (United States)

    Holm, O. S.

    1969-01-01

    Magnesium adapter ties in all of the attachment bosses on a horizontal slip table and makes a rigid coupling which terminates in a single row of attachment bosses at the edge of the horizontal plate. This eliminates ineffective dissipation of the driving force in vibration tests.

  1. Net Gain

    International Development Research Centre (IDRC) Digital Library (Canada)

    %) in malaria disease rates following introduction of ITNs. The results of standard clinical trials (randomized, controlled, and using sufficiently large samples) that measured impact on malaria disease in Africa are shown in Table 1. Other studies ...

  2. Does fault strengthening in laboratory rock friction experiments really depend primarily upon time and not slip?

    Science.gov (United States)

    Bhattacharya, Pathikrit; Rubin, Allan M.; Beeler, Nicholas M.

    2017-08-01

    The popular constitutive formulations of rate-and-state friction offer two end-member views on whether friction evolves only with slip (Slip law) or with time even without slip (Aging law). While rate stepping experiments show support for the Slip law, laboratory-observed frictional behavior near-zero slip rates has traditionally been inferred as supporting Aging law style time-dependent healing, in particular, from the slide-hold-slide experiments of Beeler et al. (1994). Using a combination of new analytical results and explicit numerical (Bayesian) inversion, we show instead that the slide-hold-slide data of Beeler et al. (1994) favor slip-dependent state evolution during holds. We show that, while the stiffness-independent rate of growth of peak stress (following reslides) with hold duration is a property shared by both the Aging and (under a more restricted set of parameter combinations) Slip laws, the observed stiffness dependence of the rate of stress relaxation during long holds is incompatible with the Aging law with constant rate-state parameters. The Slip law consistently fits the evolution of the stress minima at the end of the holds well, whether fitting jointly with peak stresses or otherwise. But neither the Aging nor Slip laws fit all the data well when a - b is constrained to values derived from prior velocity steps. We also attempted to fit the evolution of stress peaks and minima with the Kato-Tullis hybrid law and the shear stress-dependent Nagata law, both of which, even with the freedom of an extra parameter, generally reproduced the best Slip law fits to the data.

  3. Relating stick-slip friction experiments to earthquake source parameters

    Science.gov (United States)

    McGarr, Arthur F.

    2012-01-01

    Analytical results for parameters, such as static stress drop, for stick-slip friction experiments, with arbitrary input parameters, can be determined by solving an energy-balance equation. These results can then be related to a given earthquake based on its seismic moment and the maximum slip within its rupture zone, assuming that the rupture process entails the same physics as stick-slip friction. This analysis yields overshoots and ratios of apparent stress to static stress drop of about 0.25. The inferred earthquake source parameters static stress drop, apparent stress, slip rate, and radiated energy are robust inasmuch as they are largely independent of the experimental parameters used in their estimation. Instead, these earthquake parameters depend on C, the ratio of maximum slip to the cube root of the seismic moment. C is controlled by the normal stress applied to the rupture plane and the difference between the static and dynamic coefficients of friction. Estimating yield stress and seismic efficiency using the same procedure is only possible when the actual static and dynamic coefficients of friction are known within the earthquake rupture zone.

  4. Seismicity and tectonic tremor accompany the 2014 Gisborne Slow Slip Event: Insights from the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip (HOBITSS) Experiment, New Zealand

    Science.gov (United States)

    Todd, E. K.; Schwartz, S. Y.; Sheehan, A. F.; Mochizuki, K.

    2016-12-01

    The northern Hikurangi Margin is host to some of the shallowest slow slip events (SSEs) in the world. Slow slip offshore Gisborne, New Zealand has been observed at depths as shallow as 2 km and may extend all the way to the trench. Gisborne SSEs are accompanied by tectonic tremor and increased levels of seismicity, but this activity has only been observed at the onshore, downdip edge of the slow slip patch. Between May 2014 and June 2015, 24 absolute pressure gauges, 10 broadband seismometers, and 5 short period seismometers were deployed offshore Gisborne along the east coast of the North Island of New Zealand as part of the HOBITSS Experiment. These instruments were in place during a large Gisborne SSE (peak slip 20 cm) in September and October 2014. Using this new ocean-derived dataset in conjunction with existing land data from the New Zealand National Seismograph Network operated by GeoNet (http://geonet.org.nz), we present an in-depth, systematic investigation of tremor and microseismicity associated with this shallow Gisborne SSE to further examine the spatial heterogeneity of slip processes on the shallow megathrust. Tremor and earthquakes are collocated with the geodetically inverted slow slip patch with tremor occurring offshore and earthquakes concentrated downdip of a shallowly subducted seamount near the region of peak displacement during the SSE. This discovery indicates that the region of the megathrust slipping in these SSEs is capable of multiple types of slip and understanding the spatiotemporal relationships between these strain release modes has implications for local seismic hazards.

  5. Complications Related to the Treatment of Slipped Capital Femoral Epiphysis.

    Science.gov (United States)

    Roaten, John; Spence, David D

    2016-04-01

    Slipped capital femoral epiphysis (SCFE) is a condition of the immature hip in which mechanical overload of the proximal femoral physis results in anterior and superior displacement of the femoral metaphysis relative to the epiphysis. The treatment of SCFE is surgical, as the natural history of nonsurgical treatment is slip progression and early arthritis. Despite advances in treatment, much controversy exists regarding the best treatment, and complication rates remain high. Complications include osteonecrosis, chondrolysis, SCFE-induced impingement, and related articular degeneration, fixation failure and deformity progression, growth disturbance of the proximal femur, and development of bilateral disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Slip-stacking Dynamics for High-Power Proton Beams at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Jeffrey Scott [Indiana Univ., Bloomington, IN (United States)

    2015-12-01

    Slip-stacking is a particle accelerator configuration used to store two particle beams with different momenta in the same ring. The two beams are longitudinally focused by two radiofrequency (RF) cavities with a small frequency difference between them. Each beam is synchronized to one RF cavity and perturbed by the other RF cavity. Fermilab uses slip-stacking in the Recycler so as to double the power of the 120 GeV proton beam in the Main Injector. This dissertation investigates the dynamics of slip-stacking beams analytically, numerically and experimentally. In the analytic analysis, I find the general trajectory of stable slip-stacking particles and identify the slip-stacking parametric resonances. In the numerical analysis, I characterize the stable phase-space area and model the particle losses. In particular, I evaluate the impact of upgrading the Fermilab Booster cycle-rate from 15 Hz to 20 Hz as part of the Proton Improvement Plan II (PIP-II). The experimental analysis is used to verify my approach to simulating slip-stacking loss. I design a study for measuring losses from the longitudinal single-particle dynamics of slip-stacking as a function of RF cavity voltage and RF frequency separation. I further propose the installation of a harmonic RF cavity and study the dynamics of this novel slip-stacking configuration. I show the harmonic RF cavity cancels out parametric resonances in slip-stacking, reduces emittance growth during slip-stacking, and dramatically enhances the stable phase-space area. The harmonic cavity is expected to reduce slip-stacking losses to far exceed PIP-II requirements. These results raise the possibility of extending slip-stacking beyond the PIP-II era.

  7. SLIP VELOCITY IN PULSED DISC AND DOUGHNUT EXTRACTION COLUMN

    Directory of Open Access Journals (Sweden)

    Mohammad Outokesh

    2011-09-01

    Full Text Available In the present work, slip velocity has been measured in a 76 mm diameter pulsed disc and doughnut extraction column for four different liquid-liquid systems. The effects of operating variables including pulsation intensity and dispersed and continuous phase flow rates on slip velocity have been investigated. The existence of three different operational regimes, namely mixersettler, transition, and emulsion regimes, was observed when the energy input was changed. Empirical correlations are derived for prediction of the slip velocity in terms of operating variables, physical properties of the liquid systems, and column geometry for different regimes. Good agreement between prediction and experiments was found for all operating conditions that were investigated.

  8. Slips of the Pun

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    2008-01-01

    of view. On the one hand, it obviously raises the question of signification and interpretation. On the other hand, it seems to pun on the double meaning of the word ‘sense’, thus signifying not only ‘meaning’, but also ‘sensuality’. In this way, Ashbery’s poem turns out to read as ‘two different stories...... sexual presence of the lost lover. The poem playfully entangles one story with the other so as to make them barely distinguishable. Incessant wordplay makes it henceforth impossible to tell the difference between a spiritual and a fleshly reading of the poem, and perhaps such a difference does not really...... matter in the end. At any rate, the reader is left wondering how literally he ought to take the poet-speaker’s punning prediction that he and his lover “’ll/Stay in touch”. And what about the reader’s own attempt to ‘make sense’ of Ashbery’s puns? To which extent does he or she become engaged in a sexual...

  9. Fiber-Reinforced Slip Castings

    Science.gov (United States)

    Blome, J. C.; Drennan, D. N.; Keeser, H. M.

    1982-01-01

    Addition of silica fibers greatly reduces shrinkage and cracking during casting of ceramics. Fiber-reinforced slip-cast silica ceramics are also tougher and have lower dielectric loss. Silica fibers are hyperpure material containing only 1 part per million total metal-ion impurities. Hyperpure fibers ensure high reflectance and allow casting to be fired at temperature greater than 2,200 degrees F without loss of strength from devitrification.

  10. Slow slip events in the early part of the earthquake cycle

    Science.gov (United States)

    Voss, Nicholas K.; Malservisi, Rocco; Dixon, Timothy H.; Protti, Marino

    2017-08-01

    In February 2014 a Mw = 7.0 slow slip event (SSE) took place beneath the Nicoya Peninsula, Costa Rica. This event occurred 17 months after the 5 September 2012, Mw = 7.6, earthquake and along the same subduction zone segment, during a period when significant postseismic deformation was ongoing. A second SSE occurred in the middle of 2015, 21 months after the 2014 SSE and 38 months after the earthquake. The recurrence interval for Nicoya SSEs was unchanged by the earthquake. However, the spatial distribution of slip for the 2014 event differed significantly from previous events, having only deep ( 40 km) slip, compared to previous events, which had both deep and shallow slip. The 2015 SSE marked a return to the combination of deep plus shallow slip of preearthquake SSEs. However, slip magnitude in 2015 was nearly twice as large (Mw = 7.2) as preearthquake SSEs. We employ Coulomb Failure Stress change modeling in order to explain these changes. Stress changes associated with the earthquake and afterslip were highest near the shallow portion of the megathrust, where preearthquake SSEs had significant slip. Lower stress change occurred on the deeper parts of the plate interface, perhaps explaining why the deep ( 40 km) region for SSEs remained unchanged. The large amount of shallow slip in the 2015 SSE may reflect lack of shallow slip in the prior SSE. These observations highlight the variability of aseismic strain release rates throughout the earthquake cycle.type="synopsis">type="main">Plain Language SummaryWe analyzed small signals in continuous GPS time series. By averaging many GPS measurements over a day, we are able to get very precise measurements of the motion of the ground. We found two events in the Nicoya Peninsula of Costa Rica where the GPS changed direction and began moving toward the oceanic trench in the opposite direction of subduction plate motion. These events are called slow slip events and have been found in other regions such as Cascadia, Alaska

  11. Rushing, distraction, walking on contaminated floors and risk of slipping in limited-service restaurants: a case--crossover study.

    Science.gov (United States)

    Verma, Santosh K; Lombardi, David A; Chang, Wen Ruey; Courtney, Theodore K; Huang, Yueng-Hsiang; Brennan, Melanye J; Mittleman, Murray A; Ware, James H; Perry, Melissa J

    2011-08-01

    This nested case-crossover study examined the association between rushing, distraction and walking on a contaminated floor and the rate of slipping, and whether the effects varied according to weekly hours worked, job tenure and use of slip-resistant shoes. At baseline, workers from 30 limited-service restaurants in the USA reported average work hours, average weekly duration of exposure to each transient risk factor and job tenure at the current location. Use of slip-resistant shoes was determined. During the following 12 weeks, participants reported weekly their slip experience and exposures to the three transient exposures at the time of slipping. The case-crossover design was used to estimate the rate ratios using the Mantel-Haenszel estimator for person-time data. Among 396 participants providing baseline information, 210 reported one or more slips with a total of 989 slips. Rate of slipping was 2.9 times higher when rushing as compared to working at a normal pace (95% CI 2.5 to 3.3). Rate of slipping was also significantly increased by distraction (rate ratio (RR) 1.7, 95% CI 1.5 to 2.0) and walking on a contaminated floor (RR 14.6, 95% CI 12.6 to 17.0). Use of slip-resistant shoes decreased the effects of rushing and walking on a contaminated floor. Rate ratios for all three transient factors decreased monotonically as job tenure increased. The results suggest the importance of these transient risk factors, particularly floor contamination, on rate of slipping in limited-service restaurant workers. Stable characteristics, such as slip-resistant shoes, reduced the effects of transient exposures.

  12. Critical Nucleation Length for Accelerating Frictional Slip

    Science.gov (United States)

    Aldam, Michael; Weikamp, Marc; Spatschek, Robert; Brener, Efim A.; Bouchbinder, Eran

    2017-11-01

    The spontaneous nucleation of accelerating slip along slowly driven frictional interfaces is central to a broad range of geophysical, physical, and engineering systems, with particularly far-reaching implications for earthquake physics. A common approach to this problem associates nucleation with an instability of an expanding creep patch upon surpassing a critical length Lc. The critical nucleation length Lc is conventionally obtained from a spring-block linear stability analysis extended to interfaces separating elastically deformable bodies using model-dependent fracture mechanics estimates. We propose an alternative approach in which the critical nucleation length is obtained from a related linear stability analysis of homogeneous sliding along interfaces separating elastically deformable bodies. For elastically identical half-spaces and rate-and-state friction, the two approaches are shown to yield Lc that features the same scaling structure, but with substantially different numerical prefactors, resulting in a significantly larger Lc in our approach. The proposed approach is also shown to be naturally applicable to finite-size systems and bimaterial interfaces, for which various analytic results are derived. To quantitatively test the proposed approach, we performed inertial Finite-Element-Method calculations for a finite-size two-dimensional elastically deformable body in rate-and-state frictional contact with a rigid body under sideway loading. We show that the theoretically predicted Lc and its finite-size dependence are in reasonably good quantitative agreement with the full numerical solutions, lending support to the proposed approach. These results offer a theoretical framework for predicting rapid slip nucleation along frictional interfaces.

  13. Slip avalanche in nanoscratching of metallic glasses

    Science.gov (United States)

    Han, D. X.; Wang, G.; Ren, J. L.; Song, S. X.; Li, J.; Yi, J.; Jia, Y. D.; Xu, H.; Chan, K. C.; Liaw, P. K.

    2017-09-01

    Slip avalanches, similar to discrete earthquake events, of Zr-, Co-, and Ce-based metallic glasses during nanoscratching were investigated. Differing from the conventional continuum approach, mean-field theory, which is an inherently-discrete model, was applied to analytically compute intermittent slip avalanches. Mean-field theory was first connected with the potential energy barrier and concentration of free volume in order to study the stick-slip behavior. The results suggest that the motion behavior of free volume affects the critical slip avalanche size.

  14. Longitudinal wheel slip during ABS braking

    Science.gov (United States)

    Hartikainen, Lassi; Petry, Frank; Westermann, Stephan

    2015-02-01

    Anti-lock braking system (ABS) braking tests with two subcompact passenger cars were performed on dry and wet asphalt, as well as on snow and ice surfaces. The operating conditions of the tyres in terms of wheel slip were evaluated using histograms of the wheel slip data. The results showed different average slip levels for different road surfaces. It was also found that changes in the tyre tread stiffness affected the slip operating range through a modification of the slip value at which the maximum longitudinal force is achieved. Variation of the tyre footprint length through modifications in the inflation pressure affected the slip operating range as well. Differences in the slip distribution between vehicles with different brake controllers were also observed. The changes in slip operating range in turn modified the relative local sliding speeds between the tyre and the road. The results highlight the importance of the ABS controller's ability to adapt to changing slip-force characteristics of tyres and provide estimates of the magnitude of the effects of different tyre and road operating conditions.

  15. Slip systems, lattice rotations and dislocation boundaries

    DEFF Research Database (Denmark)

    Winther, Grethe

    2008-01-01

    Plastic deformation by slip induces rotations of the crystallographic lattice and evolution of dislocation structures. Both lattice rotations and dislocation structures exhibit a dependence on the grain orientation, which reflects underlying relations to the slip pattern. Relations between the type...... of dislocation structure formed, in particular the crystallographic alignment of dislocation boundaries, and the slip pattern are demonstrated. These relations are applied to polycrystals deformed in tension and rolling, producing good agreement with experiment for rolling but less good agreement for tension...... of these discrepancies is discussed. Finally, the implications of the relations between slip and dislocation structures for the modelling of mechanical properties are discussed....

  16. Stick and slip actuators (SSA)

    Science.gov (United States)

    Schmitt, Carl; Breguet, Jean-Marc; Bergander, Arvid; Clavel, Reymond

    2000-10-01

    Stick and Skip Actuators (SSA) are particularly well adapted to micro- robotics. A simple design, a very high intrinsic resolution (a few nanometers) and a high rigidity make them especially interesting in high precision micro-manipulations. Moreover, a smart design allows to combine the guiding and actuating function. The mechanical interface between the piezo-elements and the guiding mechanisms in an important point of the stick and slip actuators. The design of this interface and the choice of the material are very important. Both aspects have an impact on the rigidity, which has an influence on the behavior of the actuator. They have also an incidence onf the reliability (lifetime) because the design gives the contact condition and the material the wear resistance. In addition, a loading system allowing to keep the mechanical contact at this interface has a direct effect on the contact pressure. In order to confirm the performance of SSA, prototypes have been developed at the ISR. Their designs have bene made for application in optical microscopy, for manipulators in industrial assembly of micro- engineering products, for micro-factory, chemical and bio-engineering equipment for research or routine tasks, such as testing, screening etc. This paper presents a short description of several SSA made by the IRS and describes the parameters characterizing the stick and slip motion and the mechanical interface.

  17. Slip and flow dynamics of polydisperse thin polystyrene films.

    Science.gov (United States)

    Sabzevari, Seyed Mostafa; McGraw, Joshua D.; Jacobs, Karin; Wood-Adams, Paula M.

    2015-03-01

    We investigate the slip of binary and ternary mixtures of nearly monodisperse polystyrene samples on Teflon-coated (AF2400) silicon wafers using dewetting experiments. Binary mixtures of long and short chains along with ternary mixtures with a fixed weight-average molecular weight Mw but different number-average molecular weight Mn were prepared. Thin films of ca. 200 nm were spin coated on mica from polymer solutions and transferred to Teflon substrates. Above the glass transition temperature Tg the films break up via nucleation and growth of holes. The hole growth rate and rim morphology are monitored as a function of Mn and annealing protocol of the films before transfer to Teflon substrates. Slip properties, accessed using hydrodynamic models, and flow dynamics are then examined and compared. We found that the rim morphology and slip of polystyrene blends on Teflon depends on the molecular weight distribution. Similarly, flow dynamics is affected by the presence of short chains in mixture. Moreover, we can provoke differences in slip by choosing appropriate annealing and film transfer protocols for PS films that have first been spin cast on mica surfaces.

  18. NA-NET numerical analysis net

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J. [Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science]|[Oak Ridge National Lab., TN (United States); Rosener, B. [Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host ``na-net.ornl.gov`` at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message ``send index`` to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user`s perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  19. NA-NET numerical analysis net

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J. (Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science Oak Ridge National Lab., TN (United States)); Rosener, B. (Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science)

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host na-net.ornl.gov'' at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message send index'' to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user's perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  20. Acceleration Slip Regulation Strategy for Distributed Drive Electric Vehicles with Independent Front Axle Drive Motors

    Directory of Open Access Journals (Sweden)

    Lingfei Wu

    2015-05-01

    Full Text Available This paper presents an acceleration slip regulation strategy for distributed drive electric vehicles with two motors on the front axle. The tasks of the strategy include controlling the slip ratio to make full use of the road grip and controlling the yaw rate to eliminate the lateral movement due to the difference between motor torques. The rate of the slip ratio change can be controlled by controlling the motor torque, so that the slip ratio can be controlled by applying a proportional-integral control strategy to control the rate of the slip ratio change. The yaw rate can be controlled to almost zero by applying torque compensation based on yaw rate feedback. A coordination control strategy for the slip ratio control and yaw rate control is proposed based on analysis of the priorities and features of the two control processes. Simulations were carried out using MATLAB/Simulink, and experiments were performed on a hardware-in-loop test bench with actual motors. The results of the simulations and experiments showed that the proposed strategy could improve the longitudinal driving performance and straight line driving stability of the vehicle.

  1. Net Gain: A New Method for Preventing Malaria Deaths | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    A finely spun net could prevent as many as one-third of all child deaths in Africa, reports IDRC's new publication, Net Gain. Studies conducted in Gambia, Ghana, and Kenya show that the insecticide-treated mosquito net reduced the mortality rate of children under 5 years of age by up to 63 percent. Net Gain reviews and ...

  2. Slip detection and grip adjustment using optical tracking in prosthetic hands.

    Science.gov (United States)

    Roberts, Luke; Singhal, Girish; Kaliki, Rahul

    2011-01-01

    We have designed a closed loop control system that adjusts the grasping force of a prosthetic hand based on the amount of object slip detected by an optical tracking sensor. The system was designed for the i-Limb (a multi-fingered prosthetic hand from Touch Bionics Inc.) and is comprised of an optical sensor embedded inside a silicone prosthetic glove and a control algorithm. In a proof of concept study to demonstrate the effectiveness of optical tracking in slip sensing, we record slip rate while increasing the weight held in the grasp of the hand and compare two cases: grip adjustment on and grip adjustment off. The average slip rate was found to be 0.314 slips/(s · oz) without grip adjustment and 0.0411 slips/(s · oz) with grip adjustment. This paper discusses the advantages of the optical approach in slip detection and presents the experiment and results utilizing the optical sensor and grip control algorithm.

  3. Ultra-thin clay layers facilitate seismic slip in carbonate faults.

    Science.gov (United States)

    Smeraglia, Luca; Billi, Andrea; Carminati, Eugenio; Cavallo, Andrea; Di Toro, Giulio; Spagnuolo, Elena; Zorzi, Federico

    2017-04-06

    Many earthquakes propagate up to the Earth's surface producing surface ruptures. Seismic slip propagation is facilitated by along-fault low dynamic frictional resistance, which is controlled by a number of physico-chemical lubrication mechanisms. In particular, rotary shear experiments conducted at seismic slip rates (1 ms -1 ) show that phyllosilicates can facilitate co-seismic slip along faults during earthquakes. This evidence is crucial for hazard assessment along oceanic subduction zones, where pelagic clays participate in seismic slip propagation. Conversely, the reason why, in continental domains, co-seismic slip along faults can propagate up to the Earth's surface is still poorly understood. We document the occurrence of micrometer-thick phyllosilicate-bearing layers along a carbonate-hosted seismogenic extensional fault in the central Apennines, Italy. Using friction experiments, we demonstrate that, at seismic slip rates (1 ms -1 ), similar calcite gouges with pre-existing phyllosilicate-bearing (clay content ≤3 wt.%) micro-layers weaken faster than calcite gouges or mixed calcite-phyllosilicate gouges. We thus propose that, within calcite gouge, ultra-low clay content (≤3 wt.%) localized along micrometer-thick layers can facilitate seismic slip propagation during earthquakes in continental domains, possibly enhancing surface displacement.

  4. Structured surfaces for a giant liquid slip.

    Science.gov (United States)

    Lee, Choongyeop; Choi, Chang-Hwan; Kim, Chang-Jin Cj

    2008-08-08

    We study experimentally how two key geometric parameters (pitch and gas fraction) of textured hydrophobic surfaces affect liquid slip. The two are independently controlled on precisely fabricated microstructures of posts and grates, and the slip length of water on each sample is measured using a rheometer system. The slip length increases linearly with the pitch but dramatically with the gas fraction above 90%, the latter trend being more pronounced on posts than on grates. Once the surfaces are designed for very large slips (>20 microm), however, further increase is not obtained in regular practice because the meniscus loses its stability. By developing near-perfect samples that delay the transition from a dewetted (Cassie) to a wetted (Wenzel) state until near the theoretical limit, we achieve giant slip lengths, as large as 185 microm.

  5. Transformation of fault slip modes in laboratory experiments

    Science.gov (United States)

    Martynov, Vasilii; Alexey, Ostapchuk; Markov, Vadim

    2017-04-01

    Slip mode of crust fault can vary because of many reasons. It's well known that fault structure, material of fault gouge, pore fluid et al. in many ways determines slip modes from creep and slow slip events to mega-earthquakes [1-3]. Therefore, the possibility of fault slip transformation due to external action is urgent question. There is popular and developing approach of fluid injection into central part of fault. The phenomenon of earthquakes induced due to pumping of water was investigated on small and large scales [4, 5]. In this work the laboratory experiments were conducted to study the evolution of the experimental fault slip when changing the properties of the interstitial fluid. The scheme of experiments is the classical slider-model set-up, in which the block under the shear force slips along the interface. In our experiments the plexiglas block 8x8x3 cm3 in size was put on the plexiglas base. The contact of the blocks was filled with a thin layer (about 3 mm thick) of a granular material. The normal load varied from 31 to 156 kPa. The shear load was applied through a spring with stiffness 60 kN/m, and the rate of spring deformation was 20 or 5 mcm/s. Two parameters were recorded during experiments: the shear force acting on the upper block (with an accuracy of 1 N) and its displacement relatively the base (with an accuracy of 0.1 μm). The gouge was composed of quartz sand (97.5%) and clay (2.5%). As a moisturizer were used different fluids with viscosity varying from 1 to 103 mPa x s. Different slip modes were simulated during slider-experiments. In our experiments slip mode is the act of instability manifested in an increase of slip velocity and a drop of shear stress acting on a movable block. The amplitude of a shear stress drop and the peak velocity of the upper block were chosen as the characteristics of the slip mode. In the laboratory experiments, slip events of one type can be achieved either as regularly recurring (regular mode) or as random

  6. Testing the time dependence of slip on the West Klamath Lake fault zone

    Science.gov (United States)

    Speth, G.; Amos, C. B.; Amidon, W. H.; Meigs, A.

    2016-12-01

    Detailed inventories of fault slip over multiple time intervals are critical to our understanding of strain accumulation and release during the earthquake cycle, as well as for resolving potential variability in slip rates over time. Such variations are potentially associated with spatially or temporally clustered earthquakes and possible time-dependent changes in shear zone strength. The West Klamath Lake fault zone (WKLFZ) in southern Oregon provides an excellent opportunity to study incremental fault slip rates because it displaces multiple generations of datable landforms and has remarkable surface expression in airborne lidar imagery. There, we utilize these lidar data and new 3He cosmogenic exposure dating to reconstruct fault slip rates over intervals ranging from 103 - 105 years. Our surficial geologic mapping along the northern extent of the WKLFZ reveals at least two generations of late-Pleistocene glacial landforms as well as several Holocene fan surfaces, all of which are progressively offset by an array of predominately down-to-the-east normal fault scarps. Dating of these features relies on 3He exposure dating of basaltic andesite boulders and depth profiles from glacial outwash terraces. Preliminary exposure dating of an offset moraine along Sevenmile Creek reveals ages consistent with the last glacial maximum ( 15 - 25 ka), suggesting normal fault slip rates of 0.1 mm/yr over this period. This estimate is consistent with slip rates determined from K-Ar dating of offset lava flows near Crater Lake, 20 km to the north. Two dozen additional samples will focus on older glacial moraines and outwash surfaces, as well as debris-flow boulders on Holocene fans. These data will test the constancy of this preliminary slip rate over time. Taken together, our results will provide a detailed slip inventory for the WKLFZ over the last 105 years, and elucidate the role of this structure in accommodating active deformation at the eastern edge of the Oregon Coast

  7. Improved ceramic slip casting technique. [application to aircraft model fabrication

    Science.gov (United States)

    Buck, Gregory M. (Inventor); Vasquez, Peter (Inventor)

    1993-01-01

    A primary concern in modern fluid dynamics research is the experimental verification of computational aerothermodynamic codes. This research requires high precision and detail in the test model employed. Ceramic materials are used for these models because of their low heat conductivity and their survivability at high temperatures. To fabricate such models, slip casting techniques were developed to provide net-form, precision casting capability for high-purity ceramic materials in aqueous solutions. In previous slip casting techniques, block, or flask molds made of plaster-of-paris were used to draw liquid from the slip material. Upon setting, parts were removed from the flask mold and cured in a kiln at high temperatures. Casting detail was usually limited with this technique -- detailed parts were frequently damaged upon separation from the flask mold, as the molded parts are extremely delicate in the uncured state, and the flask mold is inflexible. Ceramic surfaces were also marred by 'parting lines' caused by mold separation. This adversely affected the aerodynamic surface quality of the model as well. (Parting lines are invariably necessary on or near the leading edges of wings, nosetips, and fins for mold separation. These areas are also critical for flow boundary layer control.) Parting agents used in the casting process also affected surface quality. These agents eventually soaked into the mold, the model, or flaked off when releasing the case model. Different materials were tried, such as oils, paraffin, and even an algae. The algae released best, but some of it remained on the model and imparted an uneven texture and discoloration on the model surface when cured. According to the present invention, a wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell

  8. Slow slip generated by dehydration reaction coupled with slip-induced dilatancy and thermal pressurization

    Science.gov (United States)

    Yamashita, Teruo; Schubnel, Alexandre

    2016-10-01

    Sustained slow slip, which is a distinctive feature of slow slip events (SSEs), is investigated theoretically, assuming a fault embedded within a fluid-saturated 1D thermo-poro-elastic medium. The object of study is specifically SSEs occurring at the down-dip edge of seismogenic zone in hot subduction zones, where mineral dehydrations (antigorite, lawsonite, chlorite, and glaucophane) are expected to occur near locations where deep slow slip events are observed. In the modeling, we introduce dehydration reactions, coupled with slip-induced dilatancy and thermal pressurization, and slip evolution is assumed to interact with fluid pressure change through Coulomb's frictional stress. Our calculations show that sustained slow slip events occur when the dehydration reaction is coupled with slip-induced dilatancy. Specifically, slow slip is favored by a low initial stress drop, an initial temperature of the medium close to that of the dehydration reaction equilibrium temperature, a low permeability, and overall negative volume change associated with the reaction (i.e., void space created by the reaction larger than the space occupied by the fluid released). Importantly, if we do not assume slip-induced dilatancy, slip is accelerated with time soon after the slip onset even if the dehydration reaction is assumed. This suggests that slow slip is sustained for a long time at hot subduction zones because dehydration reaction is coupled with slip-induced dilatancy. Such slip-induced dilatancy may occur at the down-dip edge of seismogenic zone at hot subduction zones because of repetitive occurrence of dehydration reaction there.

  9. Texture Based Image Analysis With Neural Nets

    Science.gov (United States)

    Ilovici, Irina S.; Ong, Hoo-Tee; Ostrander, Kim E.

    1990-03-01

    In this paper, we combine direct image statistics and spatial frequency domain techniques with a neural net model to analyze texture based images. The resultant optimal texture features obtained from the direct and transformed image form the exemplar pattern of the neural net. The proposed approach introduces an automated texture analysis applied to metallography for determining the cooling rate and mechanical working of the materials. The results suggest that the proposed method enhances the practical applications of neural nets and texture extraction features.

  10. Slow slip events, the earthquake cycle, and rheological effects in Nicoya, Costa Rica

    Science.gov (United States)

    Voss, Nicholas; Malservisi, Rocco; Dixon, Timothy; Protti, Marino

    2017-04-01

    In February of 2014 a Mw=7.0 slow slip event (SSE) took place beneath the Nicoya Peninsula, Costa Rica. This event occurred 17 months after the 5 September 2012, Mw=7.6, earthquake and along the same subduction zone segment, during a period when significant postseismic deformation was ongoing. A second SSE occurred in the middle of 2015, 21 months after the 2014 SSE. SSEs prior to the earthquake were also well-recorded, allowing analysis of SSE behavior during both the late and early stages of the earthquake cycle. The recurrence interval for Nicoya SSEs was unchanged by the earthquake. However, the spatial distribution of slip for the 2014 event differed significantly from previous events, only having deep ( 40 km) slip. Previous events showed both deep and shallow slip. The 2015 SSE marked a return to earlier pattern. However, slip magnitude in 2015 was nearly twice as large (Mw=7.2) as pre-earthquake SSEs. The large amount of shallow slip in the 2015 SSE maybe a result of slip missed during the 2014 SSE. These observations highlight the variability of aseismic strain release throughout the earthquake cycle generating considerable uncertainty when considering long term strain accumulation rates. The deep slip patch in Nicoya is located near the mantle wedge. Serpentinization of the wedge is thought to be one source of fluids, commonly thought to promote SSEs and and seismic tremor. However, the presence of fluids provokes drastic changes in rheology, usually ignored when calculating simple elastic dislocation models of SSEs. Here we explore how simple models using viscoelastic rheology may change the inferred deformation field, leading to mis-estimation of the magnitude of slip, and mis-estimation of long term strain accumulation rates.

  11. Relative Effects of Asymmetry and Wall Slip on the Stability of Plane Channel Flow

    Directory of Open Access Journals (Sweden)

    Sukhendu Ghosh

    2017-12-01

    Full Text Available The effect of wall velocity slip on the stability of a pressure-driven two-dimensional asymmetric channel flow is examined by considering Navier slip condition on the channel walls. The two-parameter families of mean velocity profiles are considered to approximate the underlying asymmetric basic flow. Competing effects of skewness and maximum velocity on the stability of the flow are explored for a range of model parameters. The Orr–Sommerfeld system of the asymmetric flow is solved using a Chebyshev spectral collocation method for both symmetric and non-symmetric type slip boundary conditions. Numerical results indicate that moderate asymmetry in the basic flow has a significant role on the stability of the Poiseuille-kind parallel/nearly parallel flows. Wall slip shows a passive control on the instability of the asymmetric flow by increasing or decreasing the critical Reynolds number and the set of unstable wave numbers. The stabilizing/destabilizing effect of slip velocity on the flow instability is weak or strong depending on the presence of velocity slip at the upper or lower wall. Velocity slip has a profound grip on the flow behaviour by changing the shear rate inside the perturbed flow.

  12. Professional Enterprise NET

    CERN Document Server

    Arking, Jon

    2010-01-01

    Comprehensive coverage to help experienced .NET developers create flexible, extensible enterprise application code If you're an experienced Microsoft .NET developer, you'll find in this book a road map to the latest enterprise development methodologies. It covers the tools you will use in addition to Visual Studio, including Spring.NET and nUnit, and applies to development with ASP.NET, C#, VB, Office (VBA), and database. You will find comprehensive coverage of the tools and practices that professional .NET developers need to master in order to build enterprise more flexible, testable, and ext

  13. A Method to Determine the Slip Factor of Centrifugal Pumps through Experiment

    Science.gov (United States)

    Zhang, Yu-Liang; Zhu, Zu-Chao; Dou, Hua-Shu; Cui, Bao-Ling; Li, Yi; Xiao, Jun-Jian

    2015-04-01

    In this paper, a method to determine the slip factor of centrifugal impellers is proposed based on the experimental result of the external performance of centrifugal pumps. This proposed method is superior to the conventional experimental method, which needs not to measure the flow parameters at impeller outlet. The results show that the present method can be used to obtain the slip factor at offdesign condition in a wide range of flow rate besides at the design point.

  14. 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.

  15. Molecular Simulation of Thermo-osmotic Slip.

    Science.gov (United States)

    Ganti, Raman; Liu, Yawei; Frenkel, Daan

    2017-07-21

    Thermo-osmotic slip-the flow induced by a thermal gradient along a surface-is a well-known phenomenon, but curiously there is a lack of robust molecular-simulation techniques to predict its magnitude. Here, we compare three different molecular-simulation techniques to compute the thermo-osmotic slip at a simple solid-fluid interface. Although we do not expect the different approaches to be in perfect agreement, we find that the differences are barely significant for a range of different physical conditions, suggesting that practical molecular simulations of thermo-osmotic slip are feasible.

  16. Improved Slip Casting Of Ceramic Models

    Science.gov (United States)

    Buck, Gregory M.; Vasquez, Peter; Hicks, Lana P.

    1994-01-01

    Improved technique of investment slip casting developed for making precise ceramic wind-tunnel models. Needed in wind-tunnel experiments to verify predictions of aerothermodynamical computer codes. Ceramic materials used because of their low heat conductivities and ability to survive high temperatures. Present improved slip-casting technique enables casting of highly detailed models from aqueous or nonaqueous solutions. Wet shell molds peeled off models to ensure precise and undamaged details. Used at NASA Langley Research Center to form superconducting ceramic components from nonaqueous slip solutions. Technique has many more applications when ceramic materials developed further for such high-strength/ temperature components as engine parts.

  17. Oblique strike-slip faulting of the Cascadia submarine forearc: The Daisy Bank fault zone off central Oregon

    Science.gov (United States)

    Goldfinger, Chris; Kulm, LaVerne D.; Yeats, Robert S.; Hummon, Cheryl; Huftile, Gary J.; Niem, Alan R.; McNeill, Lisa C.

    The Cascadia submarine forearc off Oregon and Washington is deformed by numerous active WNW-trending, left-lateral strike-slip faults. The kinematics of this set of sub-parallel left-lateral faults suggests clockwise block rotation of the forearc driven by oblique subduction. One major left-lateral strike-slip fault, the 94 km-long Daisy Bank fault, located off central Oregon, was studied in detail using high-resolution AMS 150 kHz and SeaMARC-lA sidescan sonar, swath bathymetry, multichannel seismic reflection profiles and a submersible. The Daisy Bank fault zone cuts the sediments and basaltic basement of the subducting Juan de Fuca plate, and the overriding North American plate, extending from the abyssal plain to the upper slope-outer shelf region. The Daisy Bank fault, a near-vertical left-lateral fault striking 292°, is a wide structural zone with multiple scarps observed in high-resolution sidescan images. From a submersible, we observe that these scarps offset late Pleistocene gray clay and overlying olive green Holocene mud, dating fault activity as post-12 ka on the upper slope. Vertical separation along individual fault scarps ranges from a few centimeters to 130 meters. Using a retrodeformation technique with multichannel reflection records, we calculate a net slip of 2.2±0.5 km. Fault movement commenced at about 380±50 ka near the western fault tip, based upon an analysis of growth strata and correlation with deep-sea drill hole biostratigraphy. We calculate a slip rate of 5.7±2.0 mm/yr. for the Daisy Bank fault at its western end on the Juan de Fuca plate. The motion of the set of oblique faults, including the Daisy Bank fault, may accommodate a significant portion of the oblique component of plate motion along the central Cascadia margin. We propose a block rotation model by which the seawardmost part of the forearc rotates clockwise and translates northward.

  18. Buried shallow fault slip from the South Napa earthquake revealed by near-field geodesy.

    Science.gov (United States)

    Brooks, Benjamin A; Minson, Sarah E; Glennie, Craig L; Nevitt, Johanna M; Dawson, Tim; Rubin, Ron; Ericksen, Todd L; Lockner, David; Hudnut, Kenneth; Langenheim, Victoria; Lutz, Andrew; Mareschal, Maxime; Murray, Jessica; Schwartz, David; Zaccone, Dana

    2017-07-01

    Earthquake-related fault slip in the upper hundreds of meters of Earth's surface has remained largely unstudied because of challenges measuring deformation in the near field of a fault rupture. We analyze centimeter-scale accuracy mobile laser scanning (MLS) data of deformed vine rows within ±300 m of the principal surface expression of the M (magnitude) 6.0 2014 South Napa earthquake. Rather than assuming surface displacement equivalence to fault slip, we invert the near-field data with a model that allows for, but does not require, the fault to be buried below the surface. The inversion maps the position on a preexisting fault plane of a slip front that terminates ~3 to 25 m below the surface coseismically and within a few hours postseismically. The lack of surface-breaching fault slip is verified by two trenches. We estimate near-surface slip ranging from ~0.5 to 1.25 m. Surface displacement can underestimate fault slip by as much as 30%. This implies that similar biases could be present in short-term geologic slip rates used in seismic hazard analyses. Along strike and downdip, we find deficits in slip: The along-strike deficit is erased after ~1 month by afterslip. We find no evidence of off-fault deformation and conclude that the downdip shallow slip deficit for this event is likely an artifact. As near-field geodetic data rapidly proliferate and will become commonplace, we suggest that analyses of near-surface fault rupture should also use more sophisticated mechanical models and subsurface geomechanical tests.

  19. Phase-slip-induced dissipation in an atomic Bose-Hubbard system.

    Science.gov (United States)

    McKay, D; White, M; Pasienski, M; DeMarco, B

    2008-05-01

    Phase-slips control dissipation in many bosonic systems, determining the critical velocity of superfluid helium and the generation of resistance in thin superconducting wires. Technological interest has been largely motivated by applications involving nanoscale superconducting circuit elements, such as standards based on quantum phase-slip junctions. Although phase slips caused by thermal fluctuations at high temperatures are well understood, controversy remains over the role of phase slips in small-scale superconductors--in solids, problems such as uncontrolled noise sources and disorder complicate their study and application. Here we show that phase slips can lead to dissipation in a clean and well-characterized Bose-Hubbard system, by experimentally studying the transport of ultracold atoms trapped in an optical lattice. In contrast to previous work, we explore a low-velocity regime described by the three-dimensional Bose-Hubbard model that is unaffected by instabilities, and we measure the effect of temperature on the dissipation strength. The damping rate of atomic motion (the analogue of electrical resistance in a solid) in the confining parabolic potential is well fitted by a model that includes finite damping at zero temperature. The low-temperature behaviour is consistent with the theory of quantum tunnelling of phase slips, whereas at higher temperatures a crossover consistent with a transition to thermal activation of phase slips is evident. Motion-induced features reminiscent of vortices and vortex rings associated with phase slips are also observed in time-of-flight imaging. These results clarify the role of phase slips in superfluid systems. They may also be of relevance in understanding the source of metallic phases observed in thin films, or serve as a test bed for theories of bosonic dissipation based upon variants of the Bose-Hubbard model.

  20. Buried shallow fault slip from the South Napa earthquake revealed by near-field geodesy

    Science.gov (United States)

    Brooks, Benjamin A.; Minson, Sarah E.; Glennie, Craig L.; Nevitt, Johanna; Dawson, Timothy E.; Rubin, Ron S.; Ericksen, Todd; Lockner, David A.; Hudnut, Kenneth W.; Langenheim, Victoria; Lutz, Andrew; Murray, Jessica R.; Schwartz, David P.; Zaccone, Dana

    2017-01-01

    Earthquake-related fault slip in the upper hundreds of meters of Earth’s surface has remained largely unstudied because of challenges measuring deformation in the near field of a fault rupture. We analyze centimeter-scale accuracy mobile laser scanning (MLS) data of deformed vine rows within ±300 m of the principal surface expression of the M (magnitude) 6.0 2014 South Napa earthquake. Rather than assuming surface displacement equivalence to fault slip, we invert the near-field data with a model that allows for, but does not require, the fault to be buried below the surface. The inversion maps the position on a preexisting fault plane of a slip front that terminates ~3 to 25 m below the surface coseismically and within a few hours postseismically. The lack of surface-breaching fault slip is verified by two trenches. We estimate near-surface slip ranging from ~0.5 to 1.25 m. Surface displacement can underestimate fault slip by as much as 30%. This implies that similar biases could be present in short-term geologic slip rates used in seismic hazard analyses. Along strike and downdip, we find deficits in slip: The along-strike deficit is erased after ~1 month by afterslip. We find no evidence of off-fault deformation and conclude that the downdip shallow slip deficit for this event is likely an artifact. As near-field geodetic data rapidly proliferate and will become commonplace, we suggest that analyses of near-surface fault rupture should also use more sophisticated mechanical models and subsurface geomechanical tests.

  1. Slip-driven electroosmotic transport through porous media.

    Science.gov (United States)

    Gaikwad, Harshad; Mondal, Pranab Kumar

    2017-03-01

    We investigate the slip-driven transport of a Newtonian fluid through porous media under electrical double layer effect. We employ a semianalytical framework to obtain the underlying electrohydrodynamics for different configurations of porous media. We bring out an alteration in flow dynamics, stemming from interplay among the geometrical feature of the models and the interfacial slip as modulated by the electrical forcing. Further, we show the consequent effects of the underlying flow dynamics on the volumetric transport rate through different models. Also, we show the inception of reverse flow in the region close to the wall, resulting from the induced pressure gradient due to the convection of co-ions in the opposite direction to flow and pinpoint its effect of the flow rate variation under the influence of interfacial slip. We believe that the inferences obtained from the present analysis may improve the design of bio-MEMS (microelectromechanical systems) and microfluidic devices, which are used for in-situ bioremediation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Onset of aseismic creep on major strike-slip faults

    KAUST Repository

    Çakir, Ziyadin

    2012-10-02

    Time series analysis of spaceborne synthetic aperture radar (SAR) data, GPS measurements, and fi eld observations reveal that the central section of the Izmit (Turkey) fault that slipped with a supershear rupture velocity in the A.D. 1999, Mw7.4, Izmit earthquake began creeping aseismically following the earthquake. Rapid initial postseismic afterslip decayed logarithmically with time and appears to have reached a steady rate comparable to the preearthquake full fault-crossing rate, suggesting that it may continue for decades and possibly until late in the earthquake cycle. If confi rmed by future monitoring, these observations identify postseismic afterslip as a mechanism for initiating creep behavior along strike-slip faults. Long-term afterslip and/or creep has signifi cant implications for earthquake cycle models, recurrence intervals of large earthquakes, and accordingly, seismic hazard estimation along mature strike-slip faults, in particular for Istanbul which is believed to lie adjacent to a seismic gap along the North Anatolian fault in the Sea of Marmara. © 2012 Geological Society of America.

  3. Slip-stacking Dynamics and the 20 Hz Booster

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Jeffery; Zwaska, Robert

    2015-03-01

    Slip-stacking is an accumulation technique used at Fermilab since 2004 which nearly doubles the proton intensity. The Proton Improvement Plan II intensity upgrades require a reduction in slip-stacking losses by approximately a factor of 2. We study the single-particle dynamics that determine the stability of slip-stacking particles. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We show the particle loss as a function of time. We calculate the injection efficiency as a function of longitudinal emittance and aspect-ratio. We demonstrate that the losses from RF single particle dynamics can be reduced by a factor of 4-10 (depending on beam parameters) by upgrading the Fermilab Booster from a 15-Hz cycle-rate to a 20-Hz cycle-rate. We recommend a change in injection scheme to eliminate the need for a greater momentum aperture in the Fermilab Recycler.

  4. Gill net and trammel net selectivity in the northern Aegean Sea, Turkey

    Directory of Open Access Journals (Sweden)

    F. Saadet Karakulak

    2008-09-01

    Full Text Available Fishing trials were carried out with gill nets and trammel nets in the northern Aegean Sea from March 2004 to February 2005. Four different mesh sizes for the gill nets and the inner panel of trammel nets (16, 18, 20 and 22 mm bar length were used. Selectivity parameters for the five most economically important species, bogue (Boops boops, annular sea bream (Diplodus annularis, striped red mullet (Mullus surmuletus, axillary sea bream (Pagellus acarne and blotched picarel (Spicara maena, caught by the two gears were estimated. The SELECT method was used to estimate the selectivity parameters of a variety of models. Catch composition and catch proportion of several species were different in gill and trammel nets. The length frequency distributions of the species caught by the two gears were significantly different. The bi-modal model selectivity curve gave the best fit for gill net and trammel net data, and there was little difference between the modal lengths of these nets. However, a clear difference was found in catching efficiency. The highest catch rates were obtained with the trammel net. Given that many discard species and small fish are caught by gill nets and trammel nets with a mesh size of 16 mm, it is clear that these nets are not appropriate for fisheries. Consequently, the best mesh size for multispecies fisheries is 18 mm. This mesh size will considerably reduce the numbers of small sized individuals and discard species in the catch.

  5. Falls study: Proprioception, postural stability, and slips.

    Science.gov (United States)

    Sohn, Jeehoon; Kim, Sukwon

    2015-01-01

    The present study evaluated effects of exercise training on the proprioception sensitivity, postural stability, and the likelihood of slip-induced falls. Eighteen older adults (6 in balance, 6 in weight, and 6 in control groups) participated in this study. Three groups met three times per week over the course of eight weeks. Ankle and knee proprioception sensitivities and postural stability were measured. Slip-induced events were introduced for all participants before and after training. The results indicated that, overall, strength and postural stability were improved only in the training group, although proprioception sensitivity was improved in all groups. Training for older adults resulted in decreased likelihood of slip-induced falls. The study suggested that proprioception can be improved by simply being active, however, the results suggested that training would aid older adults in reducing the likelihood of slip-induced falls.

  6. Bone scintigraphy in slipped capital femoral epiphysis

    Energy Technology Data Exchange (ETDEWEB)

    Gelfand, M.J.; Strife, J.L.; Graham, E.J.; Crawford, A.H.

    1983-12-01

    Tc-/sub 99m/ diphosphonate bone scans were performed on 11 children with slipped capital femoral epiphysis. On pinhole hip images, seven hips in seven patients had increased radionuclide uptake in the physis and adjacent proximal femoral metaphysis where the slip had occurred. Three hips in three patients had decreased radionuclide uptake in the femoral head on the side of the slipped epiphysis, indicating compromise of the femoral head blood supply. Three or more months following internal fixation, three children had scintigraphy that showed loss of the usual focal uptake in the physis and adjacent proximal femoral metaphysis. Bone scintigraphy in pediatric patients with slipped capital femoral epiphysis is valuable in defining the metabolic status of the femoral head. Absence of radiopharmaceutical uptake in the affected femoral head indicates that the femoral head is at risk for development of radiographic changes associated with aseptic necrosis.

  7. Slipped capital femoral epiphysis in dogs.

    Science.gov (United States)

    Moores, A P; Owen, M R; Fews, D; Coe, R J; Brown, P J; Butterworth, S J

    2004-12-01

    In a retrospective review of 43 femoral fractures, three dogs had separation of the femoral capital epiphysis from the metaphysis in the absence of trauma. Two of these dogs also had evidence of pathology in the contralateral femoral neck including, in one dog, displacement of the capital epiphysis in relation to the metaphysis without actual separation. The case histories, radiographic features and histopathological findings of these cases were reviewed and compared with previous cases of slipped capital femoral epiphysis (SCFE) reported in dogs and also with SCFE in children. Pre-slip, acute, chronic and acute-on-chronic slips were Identified. Based on the cases reviewed, the authors advise internal fixation of stable slipped epiphyses in dogs. This may also be appropriate for unstable separations, although resorption of the femoral neck may preclude stable fixation and necessitate femoral head and neck excision.

  8. Nonequilibrium Chromosome Looping via Molecular Slip Links

    Science.gov (United States)

    Brackley, C. A.; Johnson, J.; Michieletto, D.; Morozov, A. N.; Nicodemi, M.; Cook, P. R.; Marenduzzo, D.

    2017-09-01

    We propose a model for the formation of chromatin loops based on the diffusive sliding of molecular slip links. These mimic the behavior of molecules like cohesin, which, along with the CTCF protein, stabilize loops which contribute to organizing the genome. By combining 3D Brownian dynamics simulations and 1D exactly solvable nonequilibrium models, we show that diffusive sliding is sufficient to account for the strong bias in favor of convergent CTCF-mediated chromosome loops observed experimentally. We also find that the diffusive motion of multiple slip links along chromatin is rectified by an intriguing ratchet effect that arises if slip links bind to the chromatin at a preferred "loading site." This emergent collective behavior favors the extrusion of loops which are much larger than the ones formed by single slip links.

  9. Estimating the net effect of progesterone elevation on the day of hCG on live birth rates after IVF: a cohort analysis of 3296 IVF cycles.

    Science.gov (United States)

    Venetis, Christos A; Kolibianakis, Efstratios M; Bosdou, Julia K; Lainas, George T; Sfontouris, Ioannis A; Tarlatzis, Basil C; Lainas, Tryfon G

    2015-03-01

    What is the proper way of assessing the effect of progesterone elevation (PE) on the day of hCG on live birth in women undergoing fresh embryo transfer after in vitro fertilization (IVF) using GnRH analogues and gonadotrophins? This study indicates that a multivariable approach, where the effect of the most important confounders is controlled for, can lead to markedly different results regarding the association between PE on the day of hCG and live birth rates after IVF when compared with the bivariate analysis that has been typically used in the relevant literature up to date. PE on the day of hCG is associated with decreased pregnancy rates in fresh IVF cycles. Evidence for this comes from observational studies that mostly failed to control for potential confounders. This is a retrospective analysis of a cohort of fresh IVF/intracytoplasmic sperm injection cycles (n = 3296) performed in a single IVF centre during the period 2001-2013. Patients in whom ovarian stimulation was performed with gonadotrophins and GnRH analogues. Natural cycles and cycles where stimulation involved the administration of clomiphene were excluded. In order to reflect routine clinical practice, no other exclusion criteria were imposed on this dataset. The primary outcome measure for this study was live birth defined as the delivery of a live infant after 24 weeks of gestation. We compared the association between PE on the day of hCG (defined as P > 1.5 ng/ml) and live birth rates calculated by simple bivariate analyses with that derived from multivariable logistic regression. The multivariable analysis controlled for female age, number of oocytes retrieved, number of embryos transferred, developmental stage of embryos at transfer (cleavage versus blastocyst), whether at least one good-quality embryo was transferred, the woman's body mass index, the total dose of FSH administered during ovarian stimulation and the type of GnRH analogues used (agonists versus antagonists) during ovarian

  10. Possible deep fault slip preceding the 2004 Parkfield earthquake, inferred from detailed observations of tectonic tremor

    Science.gov (United States)

    Shelly, David R.

    2009-01-01

    Earthquake predictability depends, in part, on the degree to which sudden slip is preceded by slow aseismic slip. Recently, observations of deep tremor have enabled inferences of deep slow slip even when detection by other means is not possible, but these data are limited to certain areas and mostly the last decade. The region near Parkfield, California, provides a unique convergence of several years of high-quality tremor data bracketing a moderate earthquake, the 2004 magnitude 6.0 event. Here, I present detailed observations of tectonic tremor from mid-2001 through 2008 that indicate deep fault slip both before and after the Parkfield earthquake that cannot be detected with surface geodetic instruments. While there is no obvious short-term precursor, I find unidirectional tremor migration accompanied by elevated tremor rates in the 3 months prior to the earthquake, which suggests accelerated creep on the fault ∼16 km beneath the eventual earthquake hypocenter.

  11. Slipped capital femoral epiphysis: diagnosis and management.

    Science.gov (United States)

    Peck, David

    2010-08-01

    Slipped capital femoral epiphysis is the most common hip disorder in adolescents, and it has a prevalence of 10.8 cases per 100,000 children. It usually occurs in children eight to 15 years of age, and it is one of the most commonly missed diagnoses in children. Slipped capital femoral epiphysis is classified as stable or unstable based on the stability of the physis. The condition is associated with obesity and growth surges, and it is occasionally associated with endocrine disorders such as hypothyroidism, growth hormone supplementation, hypogonadism, and panhypopituitarism. Patients usually present with limping and poorly localized pain in the hip, groin, thigh, or knee. Diagnosis is confirmed by bilateral hip radiography, which needs to include anteroposterior and frog-leg lateral views in patients with stable slipped capital femoral epiphysis, and anteroposterior and cross-table lateral views in patients with the unstable form. The goals of treatment are to prevent slip progression and avoid complications such as avascular necrosis and chondrolysis. Stable slipped capital femoral epiphysis is usually treated using in situ screw fixation. Treatment of unstable slipped capital femoral epiphysis usually involves in situ fixation, but there is controversy about the timing of surgery, value of reduction, and whether traction should be used.

  12. Numerical simulation of afterslips and slow slip events that occurred in the same area in Hyuga-nada of southwest Japan

    Science.gov (United States)

    Nakata, Ryoko; Hyodo, Mamoru; Hori, Takane

    2012-08-01

    We propose a model of numerical simulation for the coexistence of afterslip for ˜M7 earthquake and slow slip events in the Hyuga-nada region of Japan that incorporates 3-D geometry of the Philippine Sea Plate. Coseismic slip events, recurrence of slow slip events and afterslip are qualitatively reproduced using the composite law, which is a type of rate- and state-dependent friction law with higher cut-off velocity. In addition, characteristic slip distances in the area are larger than those in other seismic source areas. In our simulation, afterslip, which occurred at the velocity-weakening regime, triggered an aseismic transient event. After the termination of this event, spontaneous slow slip events repeatedly occurred in the same area. After a similar event sequence was repeated, another afterslip occurrence triggered a larger coseismic slip in a wide area including that of the slow slip events. Following this coseismic slip, the aseismic slip area was locked until the next afterslip propagation, which triggered an aseismic transient event. These results suggest that detailed observation of spatial and temporal distribution within the area of aseismic slip may indicate the potential of recurring slow slip events and future large earthquakes.

  13. WaveNet

    Science.gov (United States)

    2015-10-30

    Coastal Inlets Research Program WaveNet WaveNet is a web-based, Graphical-User-Interface ( GUI ) data management tool developed for Corps coastal...generates tabular and graphical information for project planning and design documents. The WaveNet is a web-based GUI designed to provide users with a...data from different sources, and employs a combination of Fortran, Python and Matlab codes to process and analyze data for USACE applications

  14. Coloured Petri Nets

    DEFF Research Database (Denmark)

    Jensen, Kurt

    1991-01-01

    This paper describes how Coloured Petri Nets (CP-nets) have been developed — from being a promising theoretical model to being a full-fledged language for the design, specification, simulation, validation and implementation of large software systems (and other systems in which human beings and...... use of CP-nets — because it means that the function representation and the translations (which are a bit mathematically complex) no longer are parts of the basic definition of CP-nets. Instead they are parts of the invariant method (which anyway demands considerable mathematical skills...

  15. Game Coloured Petri Nets

    DEFF Research Database (Denmark)

    Westergaard, Michael

    2006-01-01

    This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachability...... analysis of this net class, and an application of game coloured Petri nets to automatically generate easy-to-understand visualizations of the model by exploiting the knowledge that some parts of the model are not interesting from a visualization perspective (i.e. they are part of the environment...

  16. Programming NET Web Services

    CERN Document Server

    Ferrara, Alex

    2007-01-01

    Web services are poised to become a key technology for a wide range of Internet-enabled applications, spanning everything from straight B2B systems to mobile devices and proprietary in-house software. While there are several tools and platforms that can be used for building web services, developers are finding a powerful tool in Microsoft's .NET Framework and Visual Studio .NET. Designed from scratch to support the development of web services, the .NET Framework simplifies the process--programmers find that tasks that took an hour using the SOAP Toolkit take just minutes. Programming .NET

  17. Annotating Coloured Petri Nets

    DEFF Research Database (Denmark)

    Lindstrøm, Bo; Wells, Lisa Marie

    2002-01-01

    -net. An example of such auxiliary information is a counter which is associated with a token to be able to do performance analysis. Modifying colour sets and arc inscriptions in a CP-net to support a specific use may lead to creation of several slightly different CP-nets – only to support the different uses...... a method which makes it possible to associate auxiliary information, called annotations, with tokens without modifying the colour sets of the CP-net. Annotations are pieces of information that are not essential for determining the behaviour of the system being modelled, but are rather added to support...

  18. Treatment of slipped capital femoral epiphysis with a modified Dunn procedure.

    Science.gov (United States)

    Slongo, Theddy; Kakaty, Diganta; Krause, Fabian; Ziebarth, Kai

    2010-12-15

    Surgical procedures with use of traditional techniques to reposition the proximal femoral epiphysis in the treatment of slipped capital femoral epiphysis are associated with a high rate of femoral head osteonecrosis. Therefore, most surgeons advocate in situ fixation of the slipped epiphysis with acceptance of any persistent deformity in the proximal part of the femur. This residual deformity can lead to secondary osteoarthritis resulting from femoroacetabular cam impingement. We retrospectively assessed the cases of twenty-three patients with slipped capital femoral epiphysis after surgical correction with a modified Dunn procedure, an approach that included surgical hip dislocation. The study reviewed the clinical status and radiographs made at the time of surgery, as well as the intraoperative findings. At a minimum follow-up of twenty-four months after surgery, the motion of the treated hip was compared with the motion of the contralateral hip, and the radiographic findings related to the anatomy of the femoral head-neck junction, as well as signs of early osteoarthritis or osteonecrosis, were evaluated. Twenty-one patients had excellent clinical and radiographic outcomes with respect to hip function and radiographic parameters. Two patients who developed severe osteoarthritis and osteonecrosis had a poor outcome. The mean slip angle of the femoral head of 47.6° preoperatively was corrected to a normal value of 4.6° (p 0.05) from that of the normal, contralateral hips. Of the eight hips that were considered unstable in the intraoperative clinical assessment, six had been considered stable preoperatively. The treatment of slipped capital femoral epiphysis with the modified Dunn procedure allows the restoration of more normal proximal femoral anatomy by complete correction of the slip angle, such that probability of secondary osteoarthritis and femoroacetabular cam impingement may be minimized. The complication rate from this procedure in our series was low

  19. Production of nanoparticles during experimental deformation of smectite and implications for seismic slip

    Science.gov (United States)

    Aretusini, S.; Mittempergher, S.; Plümper, O.; Spagnuolo, E.; Gualtieri, A. F.; Di Toro, G.

    2017-04-01

    Nanoparticles and amorphous materials are common constituents of the shallow sections of active faults. Understanding the conditions at which nanoparticles are produced and their effects on friction can further improve our understanding of fault mechanics and earthquake energy budgets. Here we present the results of 59 rotary shear experiments conducted at room humidity conditions on gouge consisting of mixtures of smectite (Ca-montmorillonite) and quartz. Experiments with 60, 50, 25, 0 wt.% Ca-montmorillonite, were performed to investigate the influence of variable clay content on nanoparticle production and their influence on frictional processes. All experiments were performed at a normal stress of 5 MPa, slip rate of 0.0003 ≤ V ≤ 1.5 ms-1, and at a displacement of 3 m. To monitor the development of fabric and the mineralogical changes during the experiments, we investigated the deformed gouges using scanning and transmission electron microscopy combined with X-ray powder diffraction quantitative phase analysis. This integrated analytical approach reveals that, at all slip rates and compositions, the nanoparticles (grain size of 10-50 nm) are partly amorphous and result from cataclasis, wear and mechanical solid-state amorphization of smectite. The maximum production of amorphous nanoparticle occurs in the intermediate slip rate range (0.0003 ≤ V ≤ 0.1 ms-1), at the highest frictional work, and is associated to diffuse deformation and slip strengthening behavior. Instead, the lowest production of amorphous nanoparticles occurs at co-seismic slip rates (V ≥ 1.3 ms-1), at the highest frictional power and is associated with strain and heat localization and slip weakening behavior. Our findings suggest that, independently of the amount of smectite nanoparticles, they produce fault weakening only when typical co-seismic slip rates (>0.1 ms-1) are achieved. This implies that estimates of the fracture surface energy dissipated during earthquakes in natural

  20. Fatigue Hardening and Nucleation of Persistent Slip Bands in Copper

    DEFF Research Database (Denmark)

    Pedersen, Ole Bøcker; Winter, A. T.

    1982-01-01

    that there is a large volume fraction of obstacles to plastic flow which are essentially non-deformable and give rise to inclusion stresses of considerable magnitude. The much lower hardening rates in cycles after saturation when persistent slip bands have formed suggest a lower volume fraction of obstacles......, as is observed by transmission electron microscopy. A simple composite model involving an inclusion stress, a bowing stress and a passing, stress accounts for the workhardening rates semi-quantitatively in terms of observed dislocation microstructures. Possible implications for polycrystals are considered....

  1. Nonlinear dynamical triggering of slow slip

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paul A [Los Alamos National Laboratory; Knuth, Matthew W [WISCONSIN; Kaproth, Bryan M [PENN STATE; Carpenter, Brett [PENN STATE; Guyer, Robert A [Los Alamos National Laboratory; Le Bas, Pierre - Yves [Los Alamos National Laboratory; Daub, Eric G [Los Alamos National Laboratory; Marone, Chris [PENN STATE

    2010-12-10

    Among the most fascinating, recent discoveries in seismology have been the phenomena of triggered slip, including triggered earthquakes and triggered-tremor, as well as triggered slow, silent-slip during which no seismic energy is radiated. Because fault nucleation depths cannot be probed directly, the physical regimes in which these phenomena occur are poorly understood. Thus determining physical properties that control diverse types of triggered fault sliding and what frictional constitutive laws govern triggered faulting variability is challenging. We are characterizing the physical controls of triggered faulting with the goal of developing constitutive relations by conducting laboratory and numerical modeling experiments in sheared granular media at varying load conditions. In order to simulate granular fault zone gouge in the laboratory, glass beads are sheared in a double-direct configuration under constant normal stress, while subject to transient perturbation by acoustic waves. We find that triggered, slow, silent-slip occurs at very small confining loads ({approx}1-3 MPa) that are smaller than those where dynamic earthquake triggering takes place (4-7 MPa), and that triggered slow-slip is associated with bursts of LFE-like acoustic emission. Experimental evidence suggests that the nonlinear dynamical response of the gouge material induced by dynamic waves may be responsible for the triggered slip behavior: the slip-duration, stress-drop and along-strike slip displacement are proportional to the triggering wave amplitude. Further, we observe a shear-modulus decrease corresponding to dynamic-wave triggering relative to the shear modulus of stick-slips. Modulus decrease in response to dynamical wave amplitudes of roughly a microstrain and above is a hallmark of elastic nonlinear behavior. We believe that the dynamical waves increase the material non-affine elastic deformation during shearing, simultaneously leading to instability and slow-slip. The inferred

  2. Using the quantum yields of photosystem II and the rate of net photosynthesis to monitor high irradiance and temperature stress in chrysanthemum (Dendranthema grandiflora)

    DEFF Research Database (Denmark)

    Wakjera, Eshetu Janka; Körner, Oliver; Rosenqvist, Eva

    2015-01-01

    Under a dynamic greenhouse climate control regime, temperature is adjusted to optimise plant physiological responses to prevailing irradiance levels; thus, both temperature and irradiance are used by the plant to maximise the rate of photosynthesis, assuming other factors are not limiting...... irradiance, the maximum Pn and ETR were reached at 24 °C. Increased irradiance decreased the PSII operating efficiency and increased NPQ, while both high irradiance and temperature had a significant effect on the PSII operating efficiency at temperatures >28 °C. Under high irradiance and temperature, changes...... in the NPQ determined the PSII operating efficiency, with no major change in the fraction of open PSII centres (qL) (indicating a QA redox state). We conclude that 1) chrysanthemum plants cope with excess irradiance by non-radiative dissipation or a reversible stress response, with the effect on the Pn...

  3. Preventing slips and falls through leisure-time physical activity: findings from a study of limited-service restaurants.

    Directory of Open Access Journals (Sweden)

    Alberto J Caban-Martinez

    Full Text Available Physical activity has been shown to be beneficial at improving health in some medical conditions and in preventing injury. Epidemiologic studies suggest that physical activity is one factor associated with a decreased risk for slips and falls in the older (≥ 65 years adult population. While the risk of slips and falls is generally lower in younger than in older adults; little is known of the relative contribution of physical activity in preventing slips and falls in younger adults. We examined whether engagement in leisure-time physical activity (LTPA was protective of slips and falls among a younger/middle-aged (≤ 50 years old working population.475 workers from 36 limited-service restaurants in six states in the U.S. were recruited to participate in a prospective cohort study of workplace slipping. Information on LTPA was collected at the time of enrollment. Participants reported their slip experience and work hours weekly for up to 12 weeks. We investigated the association between the rate of slipping and the rate of major slipping (i.e., slips that resulted in a fall and/or injury and LTPA for workers 50 years of age and younger (n = 433, range 18-50 years old using a multivariable negative binomial generalized estimating equation model.The rate of major slips among workers who engaged in moderate (Adjusted Rate Ratio (RR  = 0.65; 95% Confidence Interval (CI  =  [0.18-2.44] and vigorous (RR = 0.64; 95%CI  =  [0.18-2.26] LTPA, while non-significant, were approximately one-third lower than the rate of major slips among less active workers.While not statistically significant, the results suggest a potential association between engagement in moderate and vigorous LTPA and the rate of major slips in younger adults. Additional studies that examine the role of occupational and non-occupational physical activity on the risk of slips, trips and falls among younger and middle aged adults appear warranted.

  4. Preventing slips and falls through leisure-time physical activity: findings from a study of limited-service restaurants.

    Science.gov (United States)

    Caban-Martinez, Alberto J; Courtney, Theodore K; Chang, Wen-Ruey; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Perry, Melissa J; Katz, Jeffrey N; Verma, Santosh K

    2014-01-01

    Physical activity has been shown to be beneficial at improving health in some medical conditions and in preventing injury. Epidemiologic studies suggest that physical activity is one factor associated with a decreased risk for slips and falls in the older (≥ 65 years) adult population. While the risk of slips and falls is generally lower in younger than in older adults; little is known of the relative contribution of physical activity in preventing slips and falls in younger adults. We examined whether engagement in leisure-time physical activity (LTPA) was protective of slips and falls among a younger/middle-aged (≤ 50 years old) working population. 475 workers from 36 limited-service restaurants in six states in the U.S. were recruited to participate in a prospective cohort study of workplace slipping. Information on LTPA was collected at the time of enrollment. Participants reported their slip experience and work hours weekly for up to 12 weeks. We investigated the association between the rate of slipping and the rate of major slipping (i.e., slips that resulted in a fall and/or injury) and LTPA for workers 50 years of age and younger (n = 433, range 18-50 years old) using a multivariable negative binomial generalized estimating equation model. The rate of major slips among workers who engaged in moderate (Adjusted Rate Ratio (RR)  = 0.65; 95% Confidence Interval (CI)  =  [0.18-2.44]) and vigorous (RR = 0.64; 95%CI  =  [0.18-2.26]) LTPA, while non-significant, were approximately one-third lower than the rate of major slips among less active workers. While not statistically significant, the results suggest a potential association between engagement in moderate and vigorous LTPA and the rate of major slips in younger adults. Additional studies that examine the role of occupational and non-occupational physical activity on the risk of slips, trips and falls among younger and middle aged adults appear warranted.

  5. Self-healing slip pulses driven by thermal decomposition: Towards identifying dynamic weakening mechanisms in seismic observations

    Science.gov (United States)

    Platt, J. D.; Viesca, R. C.; Garagash, D.

    2012-12-01

    Seismological observations indicate that earthquake ruptures commonly propagate as self-healing slip pulses, with slip duration at any location on the fault being much shorter than the total event duration [Heaton 1990]. Theoretical work has linked these slip pulses to low values of the background driving stress on the fault [Zheng and Rice 1998]. Recent experiments [Han et al. 2007;Brantut et al. 2008] have shown that fault materials may thermally decompose during shear. These endothermic reactions release pore fluid, leading to an increase in pore pressure and a decrease in temperature [Sulem and Famin 2009]. An Arrhenius kinetic controls the reaction rate, and dynamic weakening only occurs when the temperature reaches a critical temperature triggering the reaction. This abrupt change is in sharp contrast with thermal pressurization where the pore pressure increases smoothly with slip. Previous theoretical studies of thermal decomposition have focused on simple mechanical systems with imposed slip rates [Sulem and Famin 2009], or coupling to a spring-slider model [Brantut et al. 2011]. We present the first solutions to couple thermal decomposition with dynamic rupture, extending the model in Garagash [2012] to solve for self-healing slip pulses. For a range of driving stresses there are two possible slip pulses, compared with a single solution for thermal pressurization alone. One solution corresponds to small slip and a low temperature rise that precludes the reaction; the other is a larger slip solution with weakening due to thermal pressurization at the rupture tip, and weakening due to thermal decomposition in the middle of the pulse. A dramatic drop in fault strength accompanies the onset of the reaction, leading to peak slip rates coinciding with the onset of the reaction. For thermal pressurization alone the maximum strain rate always occurs at the rupture tip, and depends sensitively on the driving stress. Thermal decomposition is identified by slower

  6. Insights into the causal relationship between slow slip and tectonic tremor in Guerrero, Mexico

    Science.gov (United States)

    Villafuerte, Carlos; Cruz-Atienza, Víctor M.

    2017-08-01

    Similar to other subduction zones, tectonic tremors (TTs) and slow-slip events (SSEs) take place in the deep segment of the plate interface in Guerrero, Mexico. However, their spatial correlation in this region is not as clear as the episodic tremor and slip observed in Cascadia and Japan. In this study we provide insights into the causal relationship between TTs and SSEs in Guerrero by analyzing the evolution of the deformation fields induced by the long-term 2006 SSE together with new locations of TTs and low-frequency earthquakes (LFEs). Unlike previous studies we find that the SSE slip rate modulates the TT and LFE activity in the whole tremor region. This means that the causal relationship between the SSE and the TT activity directly depends on the stressing rate history of the tremor asperities that is modulated by the surrounding slip rate. We estimated that the frictional strength of the asperities producing tremor downdip in the sweet spot is around 3.2 kPa, which is 2.3 times smaller than the corresponding value updip in the transient zone, partly explaining the overwhelming tremor activity of the sweet spot despite that the slow slip there is smaller. Based on the LFE occurrence-rate history during the interlong-term SSE period, we determined that the short-term SSEs in Guerrero take place further downdip (about 35 km) than previously estimated, with maximum slip of about 8 mm in the sweet spot. This new model features a continuum of slow slip extending across the entire tremor region of Guerrero.

  7. Progressive slip after removal of screw fixation in slipped capital femoral epiphysis: two case reports

    Directory of Open Access Journals (Sweden)

    Engelsma Yde

    2012-11-01

    Full Text Available Abstract Introduction In slipped capital femoral epiphysis the femoral neck displaces relative to the head due to weakening of the epiphysis. Early recognition and adequate surgical fixation is essential for a good functional outcome. The fixation should be secured until the closure of the epiphysis to prevent further slippage. A slipped capital femoral epiphysis should not be confused with a femoral neck fracture. Case presentation Case 1 concerns a 15-year-old boy with an adequate initial screw fixation of his slipped capital femoral epiphysis. Unfortunately, it was thought that the epiphysis had healed and the screw was removed after 11 weeks. This caused new instability with a progressive slip of the femoral epiphysis and subsequently re-fixation and a subtrochanteric correction osteotomy was obligatory. Case 2 concerns a 13-year-old girl with persistent hip pain after screw fixation for slipped capital femoral epiphysis. The screw was removed as lysis was seen around the screw on the hip X-ray. This operation created a new unstable situation and the slip progressed resulting in poor hip function. A correction osteotomy with re-screw fixation was performed with a good functional result. Conclusion A slipped epiphysis of the hip is not considered ‘healed’ after a few months. Given the risk of progression of the slip the fixation material cannot be removed before closure of the growth plate.

  8. Net zero water

    CSIR Research Space (South Africa)

    Lindeque, M

    2013-01-01

    Full Text Available Is it possible to develop a building that uses a net zero amount of water? In recent years it has become evident that it is possible to have buildings that use a net zero amount of electricity. This is possible when the building is taken off...

  9. SolNet

    DEFF Research Database (Denmark)

    Jordan, Ulrike; Vajen, Klaus; Bales, Chris

    2014-01-01

    SolNet, founded in 2006, is the first coordinated International PhD education program on Solar Thermal Engineering. The SolNet network is coordinated by the Institute of Thermal Engineering at Kassel University, Germany. The network offers PhD courses on solar heating and cooling, conference...

  10. Kunstige neurale net

    DEFF Research Database (Denmark)

    Hørning, Annette

    1994-01-01

    Artiklen beskæftiger sig med muligheden for at anvende kunstige neurale net i forbindelse med datamatisk procession af naturligt sprog, specielt automatisk talegenkendelse.......Artiklen beskæftiger sig med muligheden for at anvende kunstige neurale net i forbindelse med datamatisk procession af naturligt sprog, specielt automatisk talegenkendelse....

  11. Source characteristics of the 2015 Mw6.5 Lefkada, Greece, strike-slip earthquake

    Science.gov (United States)

    Melgar, Diego; Ganas, Athanassios; Geng, Jianghui; Liang, Cunren; Fielding, Eric J.; Kassaras, Ioannis

    2017-03-01

    We present a kinematic slip model from the inversion of 1 Hz GPS, strong motion, and interferometric synthetic aperture radar (InSAR) data for the 2015 Mw6.5 Lefkada, Greece, earthquake. We will show that most of the slip during this event is updip of the hypocenter (10.7 km depth) with substantial slip (>0.5 m) between 5 km depth and the surface. The peak slip is 1.6 m, and the inverted rake angles show predominantly strike-slip motion. Slip concentrates mostly to the south of the hypocenter, and the source time function indicates a total duration of 17 s with peak moment rate at 6 s. We will show that a 65° dipping geometry is the most plausible due to a lack of polarity reversals in the InSAR data and good agreement with Coulomb stress modeling, aftershock locations, and regional moment tensors. We also note that there was an 20 cm peak-to-peak tsunami observed at one tide gauge station 300 km away from the earthquake. We will discuss tsunami modeling results and study the possible source of the amplitude discrepancy between the modeled and the observed data at far-field tide gauges.

  12. Gait abnormalities following slipped capital femoral epiphysis.

    Science.gov (United States)

    Song, Kit M; Halliday, Suzanne; Reilly, Chris; Keezel, William

    2004-01-01

    The authors evaluated 30 subjects with treated unilateral slipped capital femoral epiphysis and a range of severity from mild to severe to characterize gait and strength abnormalities using instrumented three-dimensional gait analysis and isokinetic muscle testing. For slip angles less than 30 degrees, kinematic, kinetic, and strength variables were not significantly different from age- and weight-matched controls. For moderate to severe slips, as slip angle increased, passive hip flexion, hip abduction, and internal rotation in the flexed and extended positions decreased significantly. Persistent pelvic obliquity, medial lateral trunk sway, and trunk obliquity in stance increased, as did extension, adduction, and external rotation during gait. Gait velocity and step length decreased with increased amount of time spent in double limb stance. Hip abductor moment, hip extension moment, knee flexion moment, and ankle dorsiflexion moment were all decreased on the involved side. Hip and knee strength also decreased with increasing slip severity. All of these changes were present on the affected and to a lesser degree the unaffected side. Body center of mass translation or pelvic obliquity in mid-stance greater than one standard deviation above normal correlated well with the impression of compensated or uncompensated Trendelenburg gait.

  13. Slip resistant properties of footwear on ice.

    Science.gov (United States)

    Gao, Chuansi; Abeysekera, John; Hirvonen, Mikko; Grönqvist, Raoul

    2004-05-15

    Current research on slipperiness of footwear has mainly focused on floors and lubricated floors. Slips and falls on icy and snowy surfaces involve not only outdoor workers, but also pedestrians and the general public; and occur in cold regions and in winter season in many parts of the world. However, in comparison with the size of the problem, research on slips and falls on icy and snowy surfaces has been scarce. The objective of this paper is to explore the slip resistant properties of footwear (soling materials, roughness and hardness) on ice. The coefficients of kinetic friction of four different soling materials (synthetic rubber, nitrile rubber, natural rubber and polyurethane) were measured on ice (-12 degrees C). The outsole roughness and hardness were also measured. Results showed that the polyurethane soling did not perform better than synthetic rubber, nitrile rubber and natural rubber on pure hard ice (-12 degrees C). Soling roughness was positively correlated with the coefficient of kinetic friction. The most slip resistant soling material (polyurethane) on floors and lubricated floors may not provide sufficient slip resistance on ice.

  14. Constraining the roughness degree of slip heterogeneity

    KAUST Repository

    Causse, Mathieu

    2010-05-07

    This article investigates different approaches for assessing the degree of roughness of the slip distribution of future earthquakes. First, we analyze a database of slip images extracted from a suite of 152 finite-source rupture models from 80 events (Mw = 4.1–8.9). This results in an empirical model defining the distribution of the slip spectrum corner wave numbers (kc) as a function of moment magnitude. To reduce the “epistemic” uncertainty, we select a single slip model per event and screen out poorly resolved models. The number of remaining models (30) is thus rather small. In addition, the robustness of the empirical model rests on a reliable estimation of kc by kinematic inversion methods. We address this issue by performing tests on synthetic data with a frequency domain inversion method. These tests reveal that due to smoothing constraints used to stabilize the inversion process, kc tends to be underestimated. We then develop an alternative approach: (1) we establish a proportionality relationship between kc and the peak ground acceleration (PGA), using a k−2 kinematic source model, and (2) we analyze the PGA distribution, which is believed to be better constrained than slip images. These two methods reveal that kc follows a lognormal distribution, with similar standard deviations for both methods.

  15. Slip in viscous contact-line movement

    Science.gov (United States)

    van Lengerich, Henrik; Steen, Paul; Breuer, Kenneth

    2011-11-01

    The typical continuum fluid dynamics formulation cannot be used to model the spreading of a liquid on a solid because a stress singularity prevents contact-line motion. It is well known that this situation can be remedied by introducing a slip. We perform Stokes-flow simulations with slip and compare these with experiments. In the experiment, liquid (squalane) is forced through two parallel sapphire plates (roughness 0.6nm), and the meniscus shape and its speed are measured. The slip-length for this liquid/solid pair has been measured previously in an independent experiment absent of contact lines (T. Schmatko et. al. PRL 94, 244501). The same geometry is used in a boundary integral method simulation, accurate to within a few molecular diameters in the vicinity of the contact-line. The slip-length in the simulations can be varied such that the meniscus shape matches the experiment. Preliminary results suggest this slip-length is an order of magnitude lower than that reported by Schmatko. Now at the University of Minnesota TC

  16. Quantifying slip balance in the earthquake cycle: Coseismic slip model constrained by interseismic coupling

    KAUST Repository

    Wang, Lifeng

    2015-11-11

    The long-term slip on faults has to follow, on average, the plate motion, while slip deficit is accumulated over shorter time scales (e.g., between the large earthquakes). Accumulated slip deficits eventually have to be released by earthquakes and aseismic processes. In this study, we propose a new inversion approach for coseismic slip, taking interseismic slip deficit as prior information. We assume a linear correlation between coseismic slip and interseismic slip deficit, and invert for the coefficients that link the coseismic displacements to the required strain accumulation time and seismic release level of the earthquake. We apply our approach to the 2011 M9 Tohoku-Oki earthquake and the 2004 M6 Parkfield earthquake. Under the assumption that the largest slip almost fully releases the local strain (as indicated by borehole measurements, Lin et al., 2013), our results suggest that the strain accumulated along the Tohoku-Oki earthquake segment has been almost fully released during the 2011 M9 rupture. The remaining slip deficit can be attributed to the postseismic processes. Similar conclusions can be drawn for the 2004 M6 Parkfield earthquake. We also estimate the required time of strain accumulation for the 2004 M6 Parkfield earthquake to be ~25 years (confidence interval of [17, 43] years), consistent with the observed average recurrence time of ~22 years for M6 earthquakes in Parkfield. For the Tohoku-Oki earthquake, we estimate the recurrence time of~500-700 years. This new inversion approach for evaluating slip balance can be generally applied to any earthquake for which dense geodetic measurements are available.

  17. Analysis of Fracture Pattern of Pulverized Quartz Formed by Stick Slip Experiment

    Science.gov (United States)

    Nishikawa, Osamu; Muto, Jun; Otsuki, Kenshiro; Kano, Harumasa; Sasaki, Osamu

    2013-04-01

    In order to clarify how wall rocks of faults are damaged, fracture pattern analysis was performed imaging experimentally pulverized rocks by a micro-focus X-ray CT. Analyzed samples are core (diameter of 2cm) of single crystals of synthetic quartz and natural quartzites, which were pre-cut 50° to the core axis and mirror-polished. Experiments were conducted with axial strain rate of 10-3/s under the confining pressure of 180 MPa and room temperature using gas apparatus. Intense fracturing of the core occurred during the stick-slip with very large stress drop. Although thin melt layer is formed on the slip plane, the core is pulverized overall by tensile fracturing characterized by apparent lack of shear deformation. X-ray CT images demonstrate the fracture pattern being strongly controlled by slip direction and shear sense. Cracks are exponentially increased toward the slip plane and concentrated in the central portion rather than outer margin of core. Cracks tend to develop parallel to core axis and at high to moderate angles (90° ~ ±50°) with the plane including both core axis and slip direction, and lean to be higher angle to the surface near the slip plane. Due to this fracture pattern, the pulverized fragments show polygonal column or needle in shape with sharp and curving edges irrespective of their sizes, and the intensely fractured slip surface exhibit distinct rugged topography of an array of ridges developed perpendicular to slip direction. Mode and distribution pattern of fractures indicate that the stress concentration at the rupture front during dynamic rupture propagation or the constructive interference of reflected seismic waves focused at the center of core are possible mechanisms of pulverization.

  18. EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice

    Science.gov (United States)

    Weikusat, Ilka; Kuiper, Ernst-Jan N.; Pennock, Gill M.; Kipfstuhl, Sepp; Drury, Martyn R.

    2017-09-01

    crystallography of the host grain.The finding that subgrain boundaries indicative of non-basal slip are as frequent as those indicating basal slip is surprising. Our evidence of frequent non-basal slip in naturally deformed polar ice core samples has important implications for discussions on ice about plasticity descriptions, rate-controlling processes which accommodate basal glide, and anisotropic ice flow descriptions of large ice masses with the wider perspective of sea level evolution.

  19. EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice

    Directory of Open Access Journals (Sweden)

    I. Weikusat

    2017-09-01

    boundaries that are not related to the crystallography of the host grain.The finding that subgrain boundaries indicative of non-basal slip are as frequent as those indicating basal slip is surprising. Our evidence of frequent non-basal slip in naturally deformed polar ice core samples has important implications for discussions on ice about plasticity descriptions, rate-controlling processes which accommodate basal glide, and anisotropic ice flow descriptions of large ice masses with the wider perspective of sea level evolution.

  20. Slipped Capital Femoral Epiphysis in Atypical Patients.

    Science.gov (United States)

    Whyte, Noelle; Sullivan, Christopher

    2016-04-01

    When patients who are thin present with knee pain, it can be easy to overlook the possibility of slipped capital femoral epiphysis (SCFE). Although 80% of patients with a "slip" are obese, thin children are not immune to this problem. Endocrinopathies, especially hypothyroidism, can be associated with SCFE. This article describes guidelines for evaluating patients for a slip and highlights some important considerations for the atypical SCFE. Patients with open growth plates with thigh or knee pain should routinely have a hip examination as part of the evaluation. Plain radiographs, with an emphasis on obtaining a frog lateral image, are usually sufficient to make the diagnosis of SCFE. Patients diagnosed with SCFE should be immediately referred to an orthopedic surgeon because treatment for this condition is always surgical. Copyright 2016, SLACK Incorporated.

  1. Slipped extraocular muscles: characteristics and surgical outcomes.

    Science.gov (United States)

    Al-Haddad, Christiane; Abdul Fattah, Maamoun

    2017-02-01

    To study the frequency and characteristics of slipped extraocular muscles after strabismus surgery and report the postoperative outcomes longitudinally. Retrospective chart review. Electronic medical records of 493 patients who underwent strabismus surgery and were found to have a slipped muscle intraoperatively were reviewed. Records were retrieved and operative reports were screened for the presence of slipped muscles. Data pertaining to the eye examination and surgery were collected, including vision, ocular motility in all positions, duction limitations, slipped muscle, empty sheath length, amount of slippage, amount of advancement, and amount of recession of the antagonist muscle. Twelve patients (mean age 29.1 ± 6.4 years; 5 males) were found to have 15 slipped medial rectus muscles. Average amount of slippage was 15.7 ± 2.0 mm; from limbus empty sheath length was 5.9 ± 1.9 mm. Average preoperative deviation was 32.2 ± 10.0 prism diopters (PD) exotropia. Mean follow-up after corrective surgery was 13.3 months (1 week to 42 months). Four patients were transiently overcorrected postoperatively (7.0 ± 7.0 PD esotropia). The rest had mean residual exotropia of 13.5 ± 9.2 PD with a change of 26.6 ± 10.3 PD from baseline (p muscle movement was 10.3 ± 2.2 mm with a mean postoperative change of 2.6 PD for each 1 mm of muscle advancement. There was no significant increase over time in the postoperative angle of deviation during all follow-up periods except for 1 patient who was re-explored after 4 years. Slipped muscle should be suspected in the presence of limited ductions and consecutive deviations after strabismus surgery. A change of 2.6 PD for every 1 mm of medial rectus muscle advancement was observed and maintained over time. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  2. Vaporization of fault water during seismic slip

    Science.gov (United States)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.

    2017-06-01

    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.

  3. Pro NET Best Practices

    CERN Document Server

    Ritchie, Stephen D

    2011-01-01

    Pro .NET Best Practices is a practical reference to the best practices that you can apply to your .NET projects today. You will learn standards, techniques, and conventions that are sharply focused, realistic and helpful for achieving results, steering clear of unproven, idealistic, and impractical recommendations. Pro .NET Best Practices covers a broad range of practices and principles that development experts agree are the right ways to develop software, which includes continuous integration, automated testing, automated deployment, and code analysis. Whether the solution is from a free and

  4. Getting to Net Zero

    Energy Technology Data Exchange (ETDEWEB)

    2016-09-01

    The technology necessary to build net zero energy buildings (NZEBs) is ready and available today, however, building to net zero energy performance levels can be challenging. Energy efficiency measures, onsite energy generation resources, load matching and grid interaction, climatic factors, and local policies vary from location to location and require unique methods of constructing NZEBs. It is recommended that Components start looking into how to construct and operate NZEBs now as there is a learning curve to net zero construction and FY 2020 is just around the corner.

  5. Instant Lucene.NET

    CERN Document Server

    Heydt, Michael

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. A step-by-step guide that helps you to index, search, and retrieve unstructured data with the help of Lucene.NET.Instant Lucene.NET How-to is essential for developers new to Lucene and Lucene.NET who are looking to get an immediate foundational understanding of how to use the library in their application. It's assumed you have programming experience in C# already, but not that you have experience with search techniques such as information retrieval theory (although there will be a l

  6. Wheel Slip Control of Vehicle ABS Using Piezoactuator-Based Valve System

    Directory of Open Access Journals (Sweden)

    Juncheol Jeon

    2014-04-01

    Full Text Available This paper presents a novel piezoactuator-based valve for vehicle ABS. The piezoactuator located in one side of a rigid beam makes a displacement required to control the pressure at a flapper-nozzle of the pneumatic valve. In order to obtain the wide control range of the pressure, a pressure modulator comprised of dual-type cylinder and piston is proposed. The governing equation of the piezovalve system which consists of the proposed piezoactuator-based valve and the pressure modulator is obtained. The longitudinal vehicle dynamics and the wheel slip condition are then formulated. In order to evaluate the performance of the proposed piezovalve system from the viewpoint of the vehicle ABS, a sliding mode controller is designed for wheel slip control. The tracking control performances for the desired wheel slip rate are evaluated and the braking performances in terms of braking distance are then presented on different road conditions (dry asphalt, wet asphalt, and wet jennite. It is clearly shown that the desired wheel slip rate is well achieved and the braking distance and braking time can be significantly reduced by using the proposed piezovalve system associated with the slip rate controller.

  7. A Thermal Technique of Fault Nucleation, Growth, and Slip

    Science.gov (United States)

    Garagash, D.; Germanovich, L. N.; Murdoch, L. C.; Martel, S. J.; Reches, Z.; Elsworth, D.; Onstott, T. C.

    2009-12-01

    -Coulomb strength criterion with standard Byerlee parameters, a fault will initiate before the net tension occurs. After a new fault is created, hot fluid can be injected into the boreholes to increase the temperature and reverse the direction of fault slip. This process can be repeated to study the formation of gouge, and how the properties of gouge control fault slip and associated seismicity. Instrumenting the site with arrays of geophones, tiltmeters, strain gauges, and displacement transducers as well as back mining - an opportunity provided by the DUSEL project - can reveal details of the fault geometry and gouge. We also expect to find small faults (with cm-scale displacement) during construction of DUSEL drifts. The same thermal technique can be used to induce slip on one of them and compare the “man-made” and natural gouges. The thermal technique appears to be a relatively simple way to rapidly change the stress field and either create slip on existing fractures or create new faults at scales up to 10 m or more.

  8. On Nucleation Properties and Spatio-Temporal Slip Evolution of Simulated Seismicity

    Science.gov (United States)

    Hillers, G.; Mai, M.; Ben-Zion, Y.

    2005-12-01

    Previous studies of spatio-temporal evolution of slip on a fault governed by rate-and-state friction employed frictional properties corresponding to fairly homogeneous faults. In most cases, the only types of heterogeneities were the lab-based depth-variations of the parameters a and b that produce transitions between stable velocity-strengthening and unstable velocity-weakening regimes. In this study we use a constant a-b profile in the seismogenic zone and heterogeneous distributions of the critical slip distance L along strike and depth to model geometrical heterogeneities of fault structures. More specifically, we perform 3D quasi-static and quasi-dynamic simulations of slip on a strike-slip fault in a continuum framework. We use families of 2D anisotropic correlated distributions of L having different correlation lengths along strike (ax) and downdip (az). We explore systematically the significance of the geometrical parameters ax, az, and the underlying distribution of L values across the fault (Gaussian or uniform) on nucleation properties and frequency-size statistics. The variations of L are chosen to provide approximate representations of faults at different evolutionary stages. Relatively smooth mature faults (like the San Andreas) are represented with distributions that have large correlation length, while distributions with small correlation lengths are used to represent rougher immature faults (like the San Jacinto and faults in the eastern CA shear zone). The 3D code with various cases of anisotropic correlated distributions of L is used to study additional issues related to observed complex behavior of seismogenic faults. These include: (1) Nucleation and arrest properties of failure episodes on heterogeneous faults governed by RSD friction. (2) Correlation between the size of the nucleation zone and the final size of simulated slip events. (3) Comparison between properties of final simulated slip histories and those of the inverted slip histories

  9. Net Zero Energy Buildings

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna; Bourrelle, Julien S.; Musall, Eike

    2010-01-01

    and identify possible renewable energy supply options which may be considered in calculations. Finally, the gap between the methodology proposed by each organisation and their respective national building code is assessed; providing an overview of the possible changes building codes will need to undergo......The international cooperation project IEA SHC Task 40 / ECBCS Annex 52 “Towards Net Zero Energy Solar Buildings”, attempts to develop a common understanding and to set up the basis for an international definition framework of Net Zero Energy Buildings (Net ZEBs). The understanding of such buildings...... parameters used in the calculations are discussed and the various renewable supply options considered in the methodologies are summarised graphically. Thus, the paper helps to understand different existing approaches to calculate energy balance in Net ZEBs, highlights the importance of variables selection...

  10. PhysioNet

    Data.gov (United States)

    U.S. Department of Health & Human Services — The PhysioNet Resource is intended to stimulate current research and new investigations in the study of complex biomedical and physiologic signals. It offers free...

  11. Ground Reaction Forces in Alternative Footwear during Slip Events

    Directory of Open Access Journals (Sweden)

    Harish Chander

    2015-04-01

    Full Text Available Slips, trips and falls are major causitive factors for occupational and non-occupational falls. Alternative footwear such has crocs and flip flops have been used in and around work places and communities that can be slip prone environments. The purpose of the study is to analyze the effects of alternative footwear [crocs (CC, flip-flops (FF] and industry standard slip resistant shoes (LT on ground reaction forces (GRFs during slip events. Eighteen healthy male participants following a repeated measures design for each footwear condition, were tested for heel kinematics during normal dry surface gait (NG; unexpected slip (US, alert slip (AS and expected slip (ES. A 3x4 repeated measures ANOVA was used to analyze the dependent vertical GRFs parameters (Mean Z-GRF and Peak Z-GRF at p = 0.05. Significant interactions between footwear and gait trials were found for Mean Z-GRF and significant main effect in gait trials for Peak Z-GRF were evident. On average significantly lower GRFs were seen in slip trials compared to normal gait. FF exhibited significantly lower GRFs during slip trials while LT demonstrated lower GRFs in normal gait. The reduced ground reaction forces during all slip events compared to normal gait can be attributed to the incomplete weight transfer on the slipping foot during the unexpected and alert slips and to the anticipation of the slippery environment in expected slips. Flip flops which had greater incidence of slips also demonstrated reduced GRFs compared to CC and LT during slip events, further suggesting incomplete weight transfer, while during normal gait, LT demonstrated reduced GRFs compared to alternative footwear owing to its cushioning midsole properties. The LT with lowest incidence of slips demonstrates to be the choice of footwear for maneuvering slippery flooring conditions and for reducing impact reaction forces during non-slippery flooring conditions. Keywords: Slips, Falls, Alternative Footwear, Ground Reaction

  12. TideNet

    Science.gov (United States)

    2015-10-30

    query tide data sources in a desired geographic region of USA and its territories (Figure 1). Users can select a tide data source through the Google Map ...select data sources according to the desired geographic region. It uses the Google Map interface to display data from different sources. Recent...Coastal Inlets Research Program TideNet The TideNet is a web-based Graphical User Interface (GUI) that provides users with GIS mapping tools to

  13. Building Neural Net Software

    OpenAIRE

    Neto, João Pedro; Costa, José Félix

    1999-01-01

    In a recent paper [Neto et al. 97] we showed that programming languages can be translated on recurrent (analog, rational weighted) neural nets. The goal was not efficiency but simplicity. Indeed we used a number-theoretic approach to machine programming, where (integer) numbers were coded in a unary fashion, introducing a exponential slow down in the computations, with respect to a two-symbol tape Turing machine. Implementation of programming languages in neural nets turns to be not only theo...

  14. Interaction Nets in Russian

    OpenAIRE

    Salikhmetov, Anton

    2013-01-01

    Draft translation to Russian of Chapter 7, Interaction-Based Models of Computation, from Models of Computation: An Introduction to Computability Theory by Maribel Fernandez. "In this chapter, we study interaction nets, a model of computation that can be seen as a representative of a class of models based on the notion of 'computation as interaction'. Interaction nets are a graphical model of computation devised by Yves Lafont in 1990 as a generalisation of the proof structures of linear logic...

  15. Programming NET 35

    CERN Document Server

    Liberty, Jesse

    2009-01-01

    Bestselling author Jesse Liberty and industry expert Alex Horovitz uncover the common threads that unite the .NET 3.5 technologies, so you can benefit from the best practices and architectural patterns baked into the new Microsoft frameworks. The book offers a Grand Tour" of .NET 3.5 that describes how the principal technologies can be used together, with Ajax, to build modern n-tier and service-oriented applications. "

  16. Hydrodynamic slip length as a surface property

    Science.gov (United States)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2016-02-01

    Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.

  17. Slip Dynamics in Small Scale Crystals

    Science.gov (United States)

    Maass, Robert; Derlet, Peter; Greer, Julia; Volkert, Cynthia

    2015-03-01

    Classical work showed that dislocation velocities are strongly dependent on applied stress. Numerous experiments have validated this for individual or groups of dislocations in macroscopic crystals by using imaging techniques combined with either mechanical data or time resolved topological data. Developments in small scale mechanical testing allow to correlate the intermittency of collective dislocation motion with the mechanical response. Discrete forward surges in displacement can be related to dislocation avalanches, which are triggered by the evolving dislocation sub-structure. We study the spatiotemporal characteristics of intermittent plastic flow in quasi-statically sheared single crystalline Au crystals with diameters between 300 nm and 10000 nm, whose displacement bursts were recorded at several kHz (Scripta Mater. 2013, 69, 586; Small, available online). Both the crystallographic slip magnitude, as well as the velocity of the slip events are exhibiting power-law scaling as. The obtained slip velocity distribution has a cubic decay at high values, and a saturated flat shoulder at lower velocities. No correlation between the slip velocity and the applied stress or plastic strain is found. Further, we present DD-simulations that are supportive of our experimental findings. The simulations suggest that the dynamics of the internal stress fields dominate the evolving dislocation structure leading to velocities that are insensitive to the applied stress - a regime indicative of microplasticity.

  18. Slip resistance testing - Zones of uncertainty

    Directory of Open Access Journals (Sweden)

    Bowman, R.

    2010-10-01

    Full Text Available This paper considers recent and current potential developments in the international standardisation of slip resistance. It identifies some limitations of the wet barefoot ramp test, such that changes should be made if it is to be more widely used. It also identifies some limitations of the new European SlipSTD Publicly Available Specification, such as insufficient allowance for the deterioration of slip resistance as tiles inevitably wear.

    Este trabajo considera los desarrollos recientes y potenciales que hay en la actualidad en el desarrollo de las normas internacionales sobre la resistencia al resbalamiento. Identifica algunas limitaciones del ensayo de la rampa para pies descalzos en húmedo, para que se realicen cambios, si se va a usar de forma más extendida. También identifica algunas limitaciones de la nueva Especificación Europea Públicamente Disponible SlipSTD, como la falta de tener en cuenta adecuadamente el deterioro de la resistencia al resbalamiento de las baldosas a medida que inevitablemente se vayan desgastando.

  19. Slip casting and nitridation of silicon powder

    Science.gov (United States)

    Seiko, Y.

    1985-01-01

    Powdered Silicon was slip-cast with a CaSO4 x 0.5H2O mold and nitrided in a N atm. containing 0 or 5 vol. % H at 1000 to 1420 deg. To remove the castings, the modeling faces were coated successively with an aq. salt soap and powdered cellulose containing Na alginate, and thus prevented the sticking problem.

  20. Net accumulation of the Greenland ice sheet

    DEFF Research Database (Denmark)

    Kiilsholm, Sissi; Christensen, Jens Hesselbjerg; Dethloff, Klaus

    2003-01-01

    improvement compared to the driving OAGCM. Estimates of the regional net balance are also better represented by the RCM. In the future climate the net balance for the Greenland Ice Sheet is reduced in all the simulation, but discrepancies between the amounts when based on ECHAM4/OPYC3 and HIRHAM are found....... In both scenarios, the estimated melt rates are larger in HIRHAM than in the driving model....

  1. Next generation GNSS single receiver cycle slip reliability

    NARCIS (Netherlands)

    Teunissen, P.J.G.; De Bakker, P.F.

    2009-01-01

    In this contribution we study the multi-frequency, carrier-phase slip detection capabilities of a single receiver. Our analysis is based on an analytical expression that we present for themulti-frequencyminimal detectable carrier phase cycle slip.

  2. States of stress and slip partitioning in a continental scale strike-slip duplex: Tectonic and magmatic implications by means of finite element modeling

    Science.gov (United States)

    Iturrieta, Pablo Cristián; Hurtado, Daniel E.; Cembrano, José; Stanton-Yonge, Ashley

    2017-09-01

    Orogenic belts at oblique convergent subduction margins accommodate deformation in several trench-parallel domains, one of which is the magmatic arc, commonly regarded as taking up the margin-parallel, strike-slip component. However, the stress state and kinematics of volcanic arcs is more complex than usually recognized, involving first- and second-order faults with distinctive slip senses and mutual interaction. These are usually organized into regional scale strike-slip duplexes, associated with both long-term and short-term heterogeneous deformation and magmatic activity. This is the case of the 1100 km-long Liquiñe-Ofqui Fault System in the Southern Andes, made up of two overlapping margin-parallel master faults joined by several NE-striking second-order faults. We present a finite element model addressing the nature and spatial distribution of stress across and along the volcanic arc in the Southern Andes to understand slip partitioning and the connection between tectonics and magmatism, particularly during the interseismic phase of the subduction earthquake cycle. We correlate the dynamics of the strike-slip duplex with geological, seismic and magma transport evidence documented by previous work, showing consistency between the model and the inferred fault system behavior. Our results show that maximum principal stress orientations are heterogeneously distributed within the continental margin, ranging from 15° to 25° counter-clockwise (with respect to the convergence vector) in the master faults and 10-19° clockwise in the forearc and backarc domains. We calculate the stress tensor ellipticity, indicating simple shearing in the eastern master fault and transpressional stress in the western master fault. Subsidiary faults undergo transtensional-to-extensional stress states. The eastern master fault displays slip rates of 5 to 10 mm/yr, whereas the western and subsidiary faults show slips rates of 1 to 5 mm/yr. Our results endorse that favorably oriented

  3. Frictional properties of the biogenic oozes from the CRISP drilling project: possible evidence of past slip-to-the-trench

    Science.gov (United States)

    Vannucchi, P.; Spagnuolo, E.; Aretusini, S.; Di Toro, G.; Tsutsumi, A.; Ujiie, K.; Namiki, Y.

    2015-12-01

    The 2011 Tohoku EQ revealed that co-seismic displacement along the megathrust can reach the deformation front of subduction zones. Since then the global significance of slip-to-the-trench has become an important field of study; hence investigation of past events at other active megathrusts is critical. Offshore SE Costa Rica the deformation front of the Caribbean forearc is formed by a ~10 km-wide accretionary wedge. Here, drill Site U141 has revealed a record of frontal thrusts detached along biogenic ooze, which correlates lithologically with the "reference" Site U1381. This biogenic ooze contains >70% of organic components.There are up to 15% silica-rich elements in the upper part of the formation, while clay increases downsection. The biogenic ooze is overlain by silty clay, in which smectite is the dominant mineral. Low- to high-velocity friction experiments were performed on the biogenic ooze and the silty clay to investigate the velocity dependence of friction and the micromechanical foundation of strain localization within fontal thrusts. These experiments were performed at slip-rates of 3 µms-1 to 3.5 ms-1and σn up to 12 MPa, under both room-humidity and water saturated conditions. These experimental results indicate that, at low slip-rates, the biogenic ooze is stronger than the silty clay. At increasing slip-rates silty clays have a positive dependence of friction, while biogenic oozes show a sharp decrease of their friction coefficient as slip-rate increases. This rate-weakening behavior of the biogenic oozes may enhance co-seismic slip along the megathrust. The implication of these mechanical measurements is that the geological structures found in the forearc toe offshore SE Costa Rica were formed by locally high slip-rates that have enhanced slip propagation to the trench. Under slow slip-rates, deformation can have localized easier by creeping within the clays than in the oozes as seen. As Tsunami earthquakes are known to form with pronounced slip

  4. Taxa alimentar no desempenho de juvenis de robalo-peva em tanque-rede=Feeding rate in the performance of juveniles of fat-snook Centropomus parallelus in net cage.

    Directory of Open Access Journals (Sweden)

    Vinicius Ronzani Cerqueira

    2011-10-01

    Full Text Available O conhecimento da taxa ótima de alimentação para uma determinada espécie não só é importante para promover o maior crescimento e a melhor eficiência na alimentação, mas também para prevenir a deterioração de qualidade de água como resultado do excesso de alimento. O presente estudo teve como objetivo avaliar o desempenho do robalo-peva, Centropomus parallelus cultivado em tanques-rede flutuantes sob o efeito de diferentes taxas alimentares (1; 1,5; 2 e 2,5% da biomassa ao dia e a taxa controle que foi até a saciedade, em condições de cultivo no ambiente natural. Durante 40 dias, cada tratamento foi avaliado em triplicatas e foram verificados os parâmetros biológicos (sobrevivência, taxa de crescimento específico, peso e comprimentos médios finais e nutricionais (taxa de conversão alimentar aparente. A análise de regressão polinomial da taxa de crescimento específico sugere que em temperaturas médias de 25°C a taxa alimentar que resulta em melhor crescimento para juvenis de robalo-peva é de 1,7% da biomassa viva por dia.Knowing the optimal feeding rate for a given species is important not only to promote higher growth and greater feeding efficiency, but also to prevent the deterioration of water quality resulting from excess food. This study aimed to evaluate the performance of the fat-snook Centropomus parallelus cultivated in net cages under the effect of different feeding rates (1, 1.5, 2 and 2.5% live biomass daily and control rate up to apparent satiation in natural environment conditions. For 40 days, each treatment was evaluated in triplicate, in which the biological parameters (survival, specific growth rate, final average weight and length and nutritional parameters (feed conversion ratio were assessed. A polynomial regression analysis of specific growth rate suggests that in average temperatures of 25°C, the feeding rate which results in best growth for juvenile fat-snook is 1.7% of live biomass per day.

  5. PROCESSING OF CONCENTRATED AQUEOUS ZIRCONIA-BIOGLASS SLIPS BY SLIP CASTING

    National Research Council Canada - National Science Library

    Leon, Beltina

    2017-01-01

    ...) bioglass, were used to produce Y-TZP- bioglass slip cast compacts. The rheological properties of concentrated aqueous Y-TZP- 64S suspensions prepared with two different glass contents: 10.5 vol% and 19.9 vol...

  6. Ultrasonographic Diagnosis of Slipped Capital Femoral Epiphysis.

    Science.gov (United States)

    Palaniappan, Manikandan; Indiran, Venkatraman; Maduraimuthu, Prabakaran

    2017-01-01

    Slipped capital femoral epiphysis (SCFE), a fracture through the physis with resultant slip of the epiphysis, is the most common hip abnormality in adolescents and is a major cause of early osteoarthritis. Plain radiograph is the initial modality used to evaluate patients with painful hip joints. Ultrasonography and magnetic resonance imaging (MRI), which do not involve radiation exposure, have also been used. This case report supports the view that ultrasound can be used as an initial, cost-effective and radiation-free modality for the evaluation of suspected SCFE. A 15-year-old male patient presented with pain in the right hip for 5 days, following a slip and fall accident while playing soccer. The patient was referred to the Department of Radio-diagnosis for ultrasound. A posterior displacement of the femoral head epiphysis with a physeal step was seen on the longitudinal section obtained over the right hip joint region. The anterior physeal step (APS) measured ~3.8 mm on the right side. The distance between the anterior rim of the acetabulum and the metaphysis measured ~20.4 mm on the affected right side and ~23.6 mm on the left side. A plain radiograph in frog leg position showed a widening of the right proximal physis below the right femoral head, with a medial and posterior slip of the right femoral head. A frontal radiograph of the pelvis taken six months before showed a widening of the proximal right femoral physis. Although MRI appears to be the most sensitive modality for identifying slips early, ultrasound may be used as a cost-effective and radiation-free alternative before proceeding with further evaluation of suspected SCFE, especially considering the demographics of the affected population.

  7. A terrestrial lidar-based workflow for determining three-dimensional slip vectors and associated uncertainties

    Science.gov (United States)

    Gold, Peter O.; Cowgill, Eric; Kreylos, Oliver; Gold, Ryan D.

    2012-01-01

    Three-dimensional (3D) slip vectors recorded by displaced landforms are difficult to constrain across complex fault zones, and the uncertainties associated with such measurements become increasingly challenging to assess as landforms degrade over time. We approach this problem from a remote sensing perspective by using terrestrial laser scanning (TLS) and 3D structural analysis. We have developed an integrated TLS data collection and point-based analysis workflow that incorporates accurate assessments of aleatoric and epistemic uncertainties using experimental surveys, Monte Carlo simulations, and iterative site reconstructions. Our scanning workflow and equipment requirements are optimized for single-operator surveying, and our data analysis process is largely completed using new point-based computing tools in an immersive 3D virtual reality environment. In a case study, we measured slip vector orientations at two sites along the rupture trace of the 1954 Dixie Valley earthquake (central Nevada, United States), yielding measurements that are the first direct constraints on the 3D slip vector for this event. These observations are consistent with a previous approximation of net extension direction for this event. We find that errors introduced by variables in our survey method result in <2.5 cm of variability in components of displacement, and are eclipsed by the 10–60 cm epistemic errors introduced by reconstructing the field sites to their pre-erosion geometries. Although the higher resolution TLS data sets enabled visualization and data interactivity critical for reconstructing the 3D slip vector and for assessing uncertainties, dense topographic constraints alone were not sufficient to significantly narrow the wide (<26°) range of allowable slip vector orientations that resulted from accounting for epistemic uncertainties.

  8. Interfacial stick–slip transition in hydroxyapatite filled high density ...

    Indian Academy of Sciences (India)

    Effect of filler addition and temperature on the stick–slip transition in high density polyethylene melt was studied. Results showed that shear stresses corresponding to stick–slip transition increases with the addition of filler. Increase in temperature also increases the shear stresses for stick–slip transition. The features of the ...

  9. Evidence for Truncated Exponential Probability Distribution of Earthquake Slip

    KAUST Repository

    Thingbaijam, Kiran K. S.

    2016-07-13

    Earthquake ruptures comprise spatially varying slip on the fault surface, where slip represents the displacement discontinuity between the two sides of the rupture plane. In this study, we analyze the probability distribution of coseismic slip, which provides important information to better understand earthquake source physics. Although the probability distribution of slip is crucial for generating realistic rupture scenarios for simulation-based seismic and tsunami-hazard analysis, the statistical properties of earthquake slip have received limited attention so far. Here, we use the online database of earthquake source models (SRCMOD) to show that the probability distribution of slip follows the truncated exponential law. This law agrees with rupture-specific physical constraints limiting the maximum possible slip on the fault, similar to physical constraints on maximum earthquake magnitudes.We show the parameters of the best-fitting truncated exponential distribution scale with average coseismic slip. This scaling property reflects the control of the underlying stress distribution and fault strength on the rupture dimensions, which determines the average slip. Thus, the scale-dependent behavior of slip heterogeneity is captured by the probability distribution of slip. We conclude that the truncated exponential law accurately quantifies coseismic slip distribution and therefore allows for more realistic modeling of rupture scenarios. © 2016, Seismological Society of America. All rights reserverd.

  10. Performance analysis of a microcontroller based slip power recovery ...

    African Journals Online (AJOL)

    Slip power recovery wound rotor induction motor drives are used in high power, limited speed range applications where control of slip power provides the variable speed drive system. In this paper, the steady state performance analysis of conventional slip power recovery scheme using static line commutated inverter in the ...

  11. Friction mechanisms and interfacial slip at fluid-solid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Leger, Liliane [Institut Universitaire de France, Laboratoire de Physique des Fluides Organises, UMR CNRS 7125, College de France, 11 Place Marcelin Berthelot, 75231 Paris (France)

    2003-01-15

    We present series of experiments based on near field laser velocimetry, developed to characterize the friction mechanisms at fluid-solid interfaces. For polymers, entangled polymer melts are sheared against smooth solid surfaces, covered by surface attached polymer chains of the same chemical species, having a controlled surface density. Direct measurements of the interfacial velocity and of the shear force allow identification of the molecular mechanisms of friction. Depending on the value of the inverse of the shear rate experienced by the polymer compared to the reptation time, the transition between a regime of high and a regime of low friction observed when increasing the shear rate can be related to disentanglement or to the extraction of the surface chains from the bulk polymer. Surfaces with adjusted friction properties can thus be designed by choosing chain anchored length and surface density. For simple fluids, the direct measurements of the interfacial velocity show that, contrary to the usual hypothesis of hydrodynamics, a simple fluid can exhibit slip at the wall. Both the surface roughness and the strength of the fluid-solid interactions fix the amplitude of wall slip, acting in an antagonistic way.

  12. Recent geodynamics of major strike-slip zones

    Directory of Open Access Journals (Sweden)

    Vladimir G. Trifonov

    2015-09-01

    In all of the cases mentioned above, strike-slip deformation was expressed only or mainly during strong earthquakes. At other times, the rate of its accumulation was small and the dominant stress conditions led to transverse shortening, rarely resulting in local lengthening of the tectonic zone. These variations are caused by the tectonic peculiarities of these zones. The sinistral component of the deformation is related to the shift of the Arabian Plate relative to the African one, but also the transverse component is related to the continental slope and is expressed by the Coastal range shortening that exists in the El Ghab segment zone. There is not only a dextral deformation component, but also a transverse component, expressed by shortening of the Fergana and Talas ranges existing in the Talas-Fergana fault zone. In both zones, the shortening component became appreciable or dominant when the strike-slip deformation rate decreased. Similar, but more local, relationships were expressed in the epicentral area of the 2003 Altai earthquake and in the Western Palmyrides.

  13. La plataforma .NET

    OpenAIRE

    Fornas Estrada, Miquel

    2008-01-01

    L'aparició de la plataforma .NET Framework ha suposat un canvi molt important en la forma de crear i distribuir aplicacions, degut a que incorpora una sèrie d'innovacions tècniques i productives que simplifiquen molt les tasques necessàries per desenvolupar un projecte. La aparición de la plataforma. NET Framework ha supuesto un cambio muy importante en la forma de crear y distribuir aplicaciones, debido a que incorpora una serie de innovaciones técnicas y productivas que simplifican mucho...

  14. Biological Petri Nets

    CERN Document Server

    Wingender, E

    2011-01-01

    It was suggested some years ago that Petri nets might be well suited to modeling metabolic networks, overcoming some of the limitations encountered by the use of systems employing ODEs (ordinary differential equations). Much work has been done since then which confirms this and demonstrates the usefulness of this concept for systems biology. Petri net technology is not only intuitively understood by scientists trained in the life sciences, it also has a robust mathematical foundation and provides the required degree of flexibility. As a result it appears to be a very promising approach to mode

  15. Solute softening and defect generation during prismatic slip in magnesium alloys

    Science.gov (United States)

    Yi, Peng; Cammarata, Robert C.; Falk, Michael L.

    2017-12-01

    Temperature and solute effects on prismatic slip of 〈a〉 dislocations in Mg are studied using molecular dynamics simulation. Prismatic slip is controlled by the low mobility screw dislocation. The screw dislocation glides on the prismatic plane through alternating cross-slip between the basal plane and the prismatic plane. In doing so, it exhibits a locking–unlocking mechanism at low temperatures and a more continuous wavy propagation at high temperatures. The dislocation dissociates into partials on the basal plane and the constriction formation of the partials is identified to be the rate-limiting process for unlocking. In addition, the diffusion of partials on the basal plane enables the formation of jogs and superjogs for prismatic slip, which lead to the generation of vacancies and dislocation loops. Solute softening in Mg alloys was observed in the presence of both Al and Y solute. The softening in prismatic slip is found to be due to solute pinning on the basal plane, instead of the relative energy change of the screw dislocation on the basal and prismatic planes, as has been hypothesized.

  16. Phase slip and telegraph noise in δ-MoN nanowires

    Science.gov (United States)

    Buh, Jože; Mrzel, Aleš; Kovič, Andrej; Kabanov, Viktor; Jagličić, Zvonko; Vrtnik, Stanislav; Koželj, Primož; Mihailović, Dragan

    2017-04-01

    We have investigated the effect of the nanowire thickness on the superconducting resistive phase transition R(T) in δ-MoN nanowires. We have characterized the width of the transition in terms of thermally-activated phase-slip theory. A large increase in the width of the transition was found with the decrease of the nanowire thickness. Discrete phase-slip fluctuations also lead to the appearance of meta-stable resistive superconducting states in current-bearing superconducting wires, with spontaneous switching between them. We have investigated the effect of the bias current on the switching rate and the stability of different resistive states.

  17. Bilateral epiphyseal migration following fixation for slipped capital femoral epiphyses in a hypothyroid child.

    Science.gov (United States)

    Walter, Richard P; Jeffery, Robert S; Holroyd, Benjamin

    2013-04-01

    Progression of slipped capital femoral epiphysis following in situ screw fixation typically occurs through loosening of the screw in the metaphysis. Epiphyseal migration off the screw due to physeal growth is rare. We report epiphyseal migration off bilateral screws in a child undergoing thyroid replacement therapy. Patients with mild and moderate slipped capital femoral epiphysis and endocrine disease should be followed-up with radiographs taken at intervals which reflect the rate of growth. Fixation should be revised if the tip of the screw approaches the physis and initial fixation with two screws may be considered.

  18. Coupled effects of dehydration reaction, dilatant strengthening and shear heating on dynamic fault slip

    Science.gov (United States)

    Yamashita, T.

    2012-12-01

    It is believed that dynamic fault slip is affected by thermal pressurization. However, dilatant strengthening and dehydration reaction may significantly affect the degree of thermal pressurization. In addition, it is not clear how such effects influence the fault slip as a whole. We theoretically study how dilatant strengthening, frictional heating and dehydration reaction are coupled and how they affect dynamic slip assuming a fault in a thermoporoelastic medium saturated with fluid. After mathematical analysis is carried out for 1D model, the behavior of 2D fault model is studied numerically. The porosity is assumed to increase with increasing fault slip following Suzuki and Yamashita (2008). Our mathematical formulation of dehydration reaction is based on Brantut et al.(2010); the dehydration reaction is assumed to be endothermic. In addition, starting from the temperature Ts, all the frictional energy is assumed to be absorbed by the dehydration reaction rather than converted into heat. Although Brantut et al.(2010) assumed a constant slip velocity, we consider the temporal evolution of slip assuming the Coulomb law of friction on the fault. We first make the analysis assuming adiabatic and undrained conditions for the 1D model. We find that three nondimensional parameters Su, P0 and G0 determine the system behavior if the initial temperature T0 and dehydration starting temperature Ts are given, where Su (>0) is a parameter proportional to the pore creation rate, P0 (>0) is the initial nondimensional frictional stress and G0 (>0) is a parameter proportional to the mass fraction of fluid released per unit of total rock mass divided by the energy change per unit volume of the slip zone. The nondimensional frictional stress P is defined by the Coulomb frictional stress divided by the initial shear stress, which suggests the relation 0Ts, where Te is the temperature. We find for Te>Ts that the evolution of P is described by the equation dP/dT=(1-P)(Su-G0*P), where

  19. Modest net autotrophy in the oligotrophic ocean

    Science.gov (United States)

    Letscher, Robert T.; Moore, J. Keith

    2017-04-01

    The metabolic state of the oligotrophic subtropical ocean has long been debated. Net community production (NCP) represents the balance of autotrophic carbon fixation with heterotrophic respiration. Many in vitro NCP estimates based on oxygen incubation methods and the corresponding scaling relationships used to predict the ecosystem metabolic balance have suggested the ocean gyres to be net heterotrophic; however, all in situ NCP methods find net autotrophy. Reconciling net heterotrophy requires significant allochthonous inputs of organic carbon to the oligotrophic gyres to sustain a preponderance of respiration over in situ production. Here we use the first global ecosystem-ocean circulation model that contains representation of the three allochthonous carbon sources to the open ocean, to show that the five oligotrophic gyres exhibit modest net autotrophy throughout the seasonal cycle. Annually integrated rates of NCP vary in the range 1.5-2.2 mol O2 m-2 yr-1 across the five gyre systems; however, seasonal NCP rates are as low as 1 ± 0.5 mmol O2 m-2 d-1 for the North Atlantic. Volumetric NCP rates are heterotrophic below the 10% light level; however, they become net autotrophic when integrated over the euphotic zone. Observational uncertainties when measuring these modest autotrophic NCP rates as well as the metabolic diversity encountered across space and time complicate the scaling up of in vitro measurements to the ecosystem scale and may partially explain the previous reports of net heterotrophy. The oligotrophic ocean is autotrophic at present; however, it could shift toward seasonal heterotrophy in the future as rising temperatures stimulate respiration.

  20. Slip flow on stagnation point over a stretching sheet in a viscoelastic nanofluid

    Science.gov (United States)

    Mohamed, M. K. A.; Noar, N. A. Z.; Salleh, M. Z.; Ishak, A.

    2017-04-01

    In this study, the numerical investigation of stagnation point flow past a stretching sheet immersed in a viscoelastic (Walter's liquid-B model) nanofluid with velocity slip condition and constant wall temperature is considered. The governing equations for the model which is non linear partial differential equations are first transformed by using similarity transformation. Then, the Runge-Kutta-Fehlberg method is employed to solve the transformed ordinary differential equations. Numerical solutions are obtained for the reduced Nusselt number, the Sherwood number and the skin friction coefficient. Further, the effects of slip parameter on the Nusselt number and the Sherwood number are analyzed and discussed. It is found that the heat and mass transfer rate is higher for the Walter's fluid compared to the classical viscous fluid and the presence of the velocity slip reduces the effects of the stretching parameter on the skin friction coefficient.

  1. Wall Slip during the Flow of Carbopol Solutions through a Parallel Plate Channel

    Science.gov (United States)

    de Souza Mendes, Paulo R.; Pédron, Jonathan; Pereira, Renata A. B.

    2008-07-01

    Experiments were performed to investigate the phenomenon of wall slip during the flow of aqueous solutions of carbopol through a parallel plate channel. The Reynolds number is low for all cases investigated, to ensure negligible development length. In the experiments, the pressure drop is measured for different flow rate values, and the results are presented in the form of curves of dimensionless average velocity versus dimensionless wall shear stress. We also performed experiments with glycerol, and the results agreed with the analytical solution available in the literature. Moreover, this agreement ensures the absence of wall slip for this Newtonian case. Comparisons between the experimental and numerical results show that (apparent) wall slip occurs when the wall shear stress is below a threshold stress of a few times the yield stress. Above this threshold, the numerical and experimental curves tend to merge.

  2. Slip-Flow and Heat Transfer of a Non-Newtonian Nanofluid in a Microtube

    Science.gov (United States)

    Niu, Jun; Fu, Ceji; Tan, Wenchang

    2012-01-01

    The slip-flow and heat transfer of a non-Newtonian nanofluid in a microtube is theoretically studied. The power-law rheology is adopted to describe the non-Newtonian characteristics of the flow, in which the fluid consistency coefficient and the flow behavior index depend on the nanoparticle volume fraction. The velocity profile, volumetric flow rate and local Nusselt number are calculated for different values of nanoparticle volume fraction and slip length. The results show that the influence of nanoparticle volume fraction on the flow of the nanofluid depends on the pressure gradient, which is quite different from that of the Newtonian nanofluid. Increase of the nanoparticle volume fraction has the effect to impede the flow at a small pressure gradient, but it changes to facilitate the flow when the pressure gradient is large enough. This remarkable phenomenon is observed when the tube radius shrinks to micrometer scale. On the other hand, we find that increase of the slip length always results in larger flow rate of the nanofluid. Furthermore, the heat transfer rate of the nanofluid in the microtube can be enhanced due to the non-Newtonian rheology and slip boundary effects. The thermally fully developed heat transfer rate under constant wall temperature and constant heat flux boundary conditions is also compared. PMID:22615961

  3. Characterization of Aseismic Fault-Slip in a Deep Hard Rock Mine Through Numerical Modelling: Case Study

    Science.gov (United States)

    Sainoki, Atsushi; Mitri, Hani S.; Chinnasane, Damodara

    2017-10-01

    Seismic moment is a predominantly utilized parameter for assessing fault-slip potential when the numerical modelling of fault-slip is carried out. However, relying on seismic moment as an indicator for fault-slip might lead to incorrect conclusions, as fault-slip can be inherently seismic or aseismic. The present study examines the behaviour of a fault in Copper Cliff Mine, Canada, with a 3D numerical model encompassing major geological structures in the area of interest. Three types of numerical analyses are conducted, namely elastic and elasto-plastic analyses in static conditions and elasto-plastic analysis in dynamic conditions. The static analyses show that the fault most likely had undergone shear failure at the pre-mining stage. It is then demonstrated that mining activities induce further shear movements along the fault plane as well as within the fault material, as the fault is composed of thick, severely fractured materials. Notwithstanding the results, no large seismic events with Mw > 0.1 were recorded within the fault from microseismic-monitoring systems between 2006 and 2014, implying that the shear movements are aseismic and static. Furthermore, microseismic database analysis using 350,000 events that took place between 2004 and 2014 indicates that the fault is not seismically active. It is found from the dynamic analysis that the maximum slip rate during fault-slip is not more than 0.3 m/s, even when the fault-slip is simulated with an instantaneous stress drop. This result substantiates the assumption that the fault is not seismically active and shear movements are dominantly aseismic. It is therefore suggested that other factors such as stress re-distribution induced by the aseismic slip be considered in order to assess damage that could be caused by the fault movements. The present study sheds light on the importance of distinguishing aseismic from seismic fault-slip for optimizing support systems in underground mines.

  4. Slip deficit and location of seismic gaps along the Dead Sea Fault

    Science.gov (United States)

    Meghraoui, Mustapha; Toussaint, Renaud; Ferry, Matthieu; Nguema-Edzang, Parfait

    2015-04-01

    The Dead Sea Fault (DSF), a ~ 1000-km-long North-South trending transform fault presents structural discontinuities and includes segments that experienced large earthquakes (Mw>7) in historical times. The Wadi Araba and Jordan Valley, the Lebanese restraining bend, the Missyaf and Ghab fault segments in Syria and the Ziyaret Fault segment in Turkey display geometrical complexities made of step overs, restraining and releasing bends that may constitute major obstacles to earthquake rupture propagation. Using active tectonics, GPS measurements and paleoseismology we investigate the kinematics and long-term/short-term slip rates along the Dead Sea fault. Tectonic geomorphology with paleoseismic trenching and archeoseismic investigations indicate repeated faulting events and left-lateral slip rate ranging from 4 mm/yr in the southern fault section to 6 mm/yr in the northern fault section. Except for the northernmost DSF section, these long-term estimates of fault slip rate are consistent with GPS measurements that show 4 to 5 mm/yr deformation rate across the plate boundary. Indeed, recent GPS results showing 3 +-0.5 mm/yr velocity rate of the northern DSF appear to be in contradiction with the ~6 mm/yr paleoseismic slip rate. The kinematic modeling that combines GPS and seismotectonic results implies a complex geodynamic pattern with the DSF transforms the Cyprus arc subduction zone into transpressive tectonics on the East Anatolian fault. The timing of past earthquake ruptures shows the occurrence of seismic sequences and a southward migration of large earthquakes, with the existence of major seismic gaps along strike. In this contribution, we present the calculated seismic slip deficit along the fault segments and discuss the identification of seismic gaps and the implication for the seismic hazard assessment.

  5. Stokes equations with penalised slip boundary conditions

    Science.gov (United States)

    Dione, Ibrahima; Tibirna, Cristian; Urquiza, José

    2013-07-01

    We consider the finite-element approximation of Stokes equations with slip boundary conditions imposed with the penalty method. In the case of a smooth curved boundary, our numerical results suggest that curved finite elements, regularised normal vectors or reduced integration techniques can be used to avoid a Babuska's-type paradox and ensure the convergence of finite-element approximations to the exact solution. Convergence orders with these remedies are also compared.

  6. Petri Nets-Applications

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 9. Petri Nets - Applications. Y Narahari. General Article Volume 4 Issue 9 September 1999 pp 44-52. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/004/09/0044-0052. Author Affiliations. Y Narahari ...

  7. Safety nets or straitjackets?

    DEFF Research Database (Denmark)

    Ilsøe, Anna

    2012-01-01

    Does regulation of working hours at national and sector level impose straitjackets, or offer safety nets to employees seeking working time flexibility? This article compares legislation and collective agreements in the metal industries of Denmark, Germany and the USA. The industry has historically...

  8. Coloured Petri Nets

    CERN Document Server

    Jensen, Kurt

    2009-01-01

    Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. This book introduces the constructs of the CPN modelling language and presents the related analysis methods. It provides a comprehensive road map for the practical use of CPN.

  9. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

  10. Game Theory .net.

    Science.gov (United States)

    Shor, Mikhael

    2003-01-01

    States making game theory relevant and accessible to students is challenging. Describes the primary goal of GameTheory.net is to provide interactive teaching tools. Indicates the site strives to unite educators from economics, political and computer science, and ecology by providing a repository of lecture notes and tests for courses using…

  11. Coloured Petri Nets

    DEFF Research Database (Denmark)

    Jensen, Kurt; Kristensen, Lars Michael

    Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. The development of such systems is particularly challenging because of inherent intricacies like possible nondeterminism...

  12. Simulating Spatio-Temporal Slip Evolution of Fault Zones at Different Evolutionary Stages

    Science.gov (United States)

    Hillers, G.; Mai, M.; Ben-Zion, Y.

    2004-12-01

    Previous studies of spatio-temporal evolution of slip on a fault governed by rate-and-state friction (e.g., Rice, 1993; Ben-Zion and Rice, 1995, 1997; Tullis, 1996; Lapusta et al., 2000) employed frictional properties corresponding to fairly homogeneous faults. In most cases, the only types of heterogeneities were the lab-based depth-variations of the parameters a and b that produce transitions between stable velocity-strengthening and unstable velocity-weakening regimes. In this study we use a constant a-b profile and a depth-dependent distribution of the critical slip distance parameter L. In addition, correlated heterogeneities of L along strike are used to model geometrical heterogeneities on faults related to roughness. More specifically, we will perform 3D quasi-static and quasi-dynamic simulations of slip on a strike-slip fault using a family of 2D anisotropic correlated distributions of L having different correlation lengths along strike and downdip. The depth-variation of L over the depth range 3km histories. The 3D code with various cases of anisotropic correlated distributions of L will be used to study many issues related to observed complex behavior of seismogenic faults including: (1) Nucleation and arrest properties of failure episodes on a heterogeneous fault governed by RSD friction. (2) Comparison between properties of final simulated slip histories and those of the inverted slip histories. (3) Frequency-size and temporal statistics of simulated earthquakes on a heterogeneous fault governed by rate-and-state friction.

  13. Sea-ice melt CO2-carbonate chemistry in the western Arctic Ocean: meltwater contributions to air-sea CO2 gas exchange, mixed layer properties and rates of net community production under sea ice

    Science.gov (United States)

    Bates, N. R.; Garley, R.; Frey, K. E.; Shake, K. L.; Mathis, J. T.

    2014-01-01

    The carbon dioxide (CO2)-carbonate chemistry of sea-ice melt and co-located, contemporaneous seawater has rarely been studied in sea ice covered oceans. Here, we describe the CO2-carbonate chemistry of sea-ice melt (both above sea ice as "melt ponds" and below sea ice as "interface waters") and mixed layer properties in the western Arctic Ocean in the early summer of 2010 and 2011. At nineteen stations, the salinity (~ 0.5 to 1500 μatm) with the majority of melt ponds acting as potentially strong sources of CO2 to the atmosphere. The pH of melt pond waters was also highly variable ranging from mildly acidic (6.1 to 7) to slightly more alkaline than underlying seawater (8 to 10.7). All of observed melt ponds had very low (pH/Ωaragonite than the co-located mixed layer beneath. Sea-ice melt thus contributed to the suppression of mixed layer pCO2 enhancing the surface ocean's capacity to uptake CO2 from the atmosphere. Meltwater contributions to changes in mixed-layer DIC were also used to estimate net community production rates (mean of 46.9 ±29.8 g C m-2 for the early-season period) under sea-ice cover. Although sea-ice melt is a transient seasonal feature, above-ice melt pond coverage can be substantial (10 to > 50%) and under-ice interface melt water is ubiquitous during this spring/summer sea-ice retreat. Our observations contribute to growing evidence that sea-ice CO2-carbonate chemistry is highly variable and its contribution to the complex factors that influence the balance of CO2 sinks and sources (and thereby ocean acidification) is difficult to predict in an era of rapid warming and sea ice loss in the Arctic Ocean.

  14. The Greenville Fault: preliminary estimates of its long-term creep rate and seismic potential

    Science.gov (United States)

    Lienkaemper, James J.; Barry, Robert G.; Smith, Forrest E.; Mello, Joseph D.; McFarland, Forrest S.

    2013-01-01

    Once assumed locked, we show that the northern third of the Greenville fault (GF) creeps at 2 mm/yr, based on 47 yr of trilateration net data. This northern GF creep rate equals its 11-ka slip rate, suggesting a low strain accumulation rate. In 1980, the GF, easternmost strand of the San Andreas fault system east of San Francisco Bay, produced a Mw5.8 earthquake with a 6-km surface rupture and dextral slip growing to ≥2 cm on cracks over a few weeks. Trilateration shows a 10-cm post-1980 transient slip ending in 1984. Analysis of 2000-2012 crustal velocities on continuous global positioning system stations, allows creep rates of ~2 mm/yr on the northern GF, 0-1 mm/yr on the central GF, and ~0 mm/yr on its southern third. Modeled depth ranges of creep along the GF allow 5-25% aseismic release. Greater locking in the southern two thirds of the GF is consistent with paleoseismic evidence there for large late Holocene ruptures. Because the GF lacks large (>1 km) discontinuities likely to arrest higher (~1 m) slip ruptures, we expect full-length (54-km) ruptures to occur that include the northern creeping zone. We estimate sufficient strain accumulation on the entire GF to produce Mw6.9 earthquakes with a mean recurrence of ~575 yr. While the creeping 16-km northern part has the potential to produce a Mw6.2 event in 240 yr, it may rupture in both moderate (1980) and large events. These two-dimensional-model estimates of creep rate along the southern GF need verification with small aperture surveys.

  15. Unified law of evolution of experimental gouge-filled fault for fast and slow slip events at slider frictional experiments

    Science.gov (United States)

    Ostapchuk, Alexey; Saltykov, Nikolay

    2017-04-01

    Excessive tectonic stresses accumulated in the area of rock discontinuity are released while a process of slip along preexisting faults. Spectrum of slip modes includes not only creeps and regular earthquakes but also some transitional regimes - slow-slip events, low-frequency and very low-frequency earthquakes. However, there is still no agreement in Geophysics community if such fast and slow events have mutual nature [Peng, Gomberg, 2010] or they present different physical phenomena [Ide et al., 2007]. Models of nucleation and evolution of fault slip events could be evolved by laboratory experiments in which regularities of shear deformation of gouge-filled fault are investigated. In the course of the work we studied deformation regularities of experimental fault by slider frictional experiments for development of unified law of evolution of fault and revelation of its parameters responsible for deformation mode realization. The experiments were conducted as a classic slider-model experiment, in which block under normal and shear stresses moves along interface. The volume between two rough surfaces was filled by thin layer of granular matter. Shear force was applied by a spring which deformed with a constant rate. In such experiments elastic energy was accumulated in the spring, and regularities of its releases were determined by regularities of frictional behaviour of experimental fault. A full spectrum of slip modes was simulated in laboratory experiments. Slight change of gouge characteristics (granule shape, content of clay), viscosity of interstitial fluid and level of normal stress make it possible to obtained gradual transformation of the slip modes from steady sliding and slow slip to regular stick-slip, with various amplitude of 'coseismic' displacement. Using method of asymptotic analogies we have shown that different slip modes can be specified in term of single formalism and preparation of different slip modes have uniform evolution law. It is shown

  16. Earthquake scaling laws for rupture geometry and slip heterogeneity

    Science.gov (United States)

    Thingbaijam, Kiran K. S.; Mai, P. Martin; Goda, Katsuichiro

    2016-04-01

    We analyze an extensive compilation of finite-fault rupture models to investigate earthquake scaling of source geometry and slip heterogeneity to derive new relationships for seismic and tsunami hazard assessment. Our dataset comprises 158 earthquakes with a total of 316 rupture models selected from the SRCMOD database (http://equake-rc.info/srcmod). We find that fault-length does not saturate with earthquake magnitude, while fault-width reveals inhibited growth due to the finite seismogenic thickness. For strike-slip earthquakes, fault-length grows more rapidly with increasing magnitude compared to events of other faulting types. Interestingly, our derived relationship falls between the L-model and W-model end-members. In contrast, both reverse and normal dip-slip events are more consistent with self-similar scaling of fault-length. However, fault-width scaling relationships for large strike-slip and normal dip-slip events, occurring on steeply dipping faults (δ~90° for strike-slip faults, and δ~60° for normal faults), deviate from self-similarity. Although reverse dip-slip events in general show self-similar scaling, the restricted growth of down-dip fault extent (with upper limit of ~200 km) can be seen for mega-thrust subduction events (M~9.0). Despite this fact, for a given earthquake magnitude, subduction reverse dip-slip events occupy relatively larger rupture area, compared to shallow crustal events. In addition, we characterize slip heterogeneity in terms of its probability distribution and spatial correlation structure to develop a complete stochastic random-field characterization of earthquake slip. We find that truncated exponential law best describes the probability distribution of slip, with observable scale parameters determined by the average and maximum slip. Applying Box-Cox transformation to slip distributions (to create quasi-normal distributed data) supports cube-root transformation, which also implies distinctive non-Gaussian slip

  17. Interplate coupling and seismic-aseismic slip patterns

    Science.gov (United States)

    Senatorski, Piotr

    2017-04-01

    Numerical simulations were carried out to explain the seismic and aseismic slip paradox. Recent observations of megathrust faults show that stable and unstable slip movements can occur at the same locations. This contradicts the previous view based on frictional sliding theories. In the present work, an asperity fault model with the slip-dependent friction and stress dependent healing is used to show that the character of slip can change, even if friction parameters, such as strength and slip-weakening distance, are fixed. The reason is that the slow versus fast slip interplay is more than just about the friction law problem. The character of slip depends both on the local friction and on the system stiffness. The stiffness is related to the slipping area size and distribution of slips, so it changes from one event to another. It is also shown that the high strength interplate patches, such as subducted seamounts, can both promote and restrain large earthquakes, depending on the slip-weakening distance lengths.

  18. Where did the time go? Friction evolves with slip following large velocity steps, normal stress steps, and (?) during long holds

    Science.gov (United States)

    Rubin, A. M.; Bhattacharya, P.; Tullis, T. E.; Okazaki, K.; Beeler, N. M.

    2016-12-01

    The popular constitutive formulations of rate-and-state friction offer two end-member views on whether friction evolves only with slip (Slip law state evolution) or with time even without slip (Aging law state evolution). While rate stepping experiments show support for the Slip law, laboratory observed frictional behavior of initially bare rock surfaces near zero slip rate has traditionally been interpreted to show support for time-dependent evolution of frictional strength. Such laboratory derived support for time-dependent evolution has been one of the motivations behind the Aging law being widely used to model earthquake cycles on natural faults.Through a combination of theoretical results and new experimental data on initially bare granite, we show stronger support for the other end member view, i.e. that friction under a wide range of sliding conditions evolves only with slip. Our dataset is unique in that it combines up to 3.5 orders of magnitude rate steps, sequences of holds up to 10000s, and 5% normal stress steps at order of magnitude different sliding rates during the same experimental run. The experiments were done on the Brown rotary shear apparatus using servo feedback, making the machine stiff enough to provide very large departures from steady-state while maintaining stable, quasi-static sliding. Across these diverse sliding conditions, and in particular for both large velocity step decreases and the longest holds, the data are much more consistent with the Slip law version of slip-dependence than the time-dependence formulated in the Aging law. The shear stress response to normal stress steps is also consistently better explained by the Slip law when paired with the Linker-Dieterich type response to normal stress perturbations. However, the remarkable symmetry and slip-dependence of the normal stress step increases and decreases suggest deficiencies in the Linker-Dieterich formulation that we will probe in future experiments.High quality

  19. Cyclic hardening and slip localization in single slip oriented copper crystals

    DEFF Research Database (Denmark)

    Pedersen, O.B.; Winter, A.T.

    1995-01-01

    A static-dynamic model is applied to the interpretation of slip localization modes observed in a systematic study of the evolution of dislocation structures in single slip intermediate amplitude fatigue in copper deformed at room temperature. The model assumes that veins do not deform plastically...... and in the more extended wall structures produced by this process are about equal. Nevertheless, the model and microscopy suggest convincingly that minimization of dislocation line energy in the dynamic structure between glissile walls and veins controls the condensation mode and the equilibrium wall spacing...

  20. Food Safety Nets:

    OpenAIRE

    Haggblade, Steven; Diallo, Boubacar; Staatz, John; Theriault, Veronique; Traoré, Abdramane

    2013-01-01

    Food and social safety nets have a history as long as human civilization. In hunter gatherer societies, food sharing is pervasive. Group members who prove unlucky in the short run, hunting or foraging, receive food from other households in anticipation of reciprocal consideration at a later time (Smith 1988). With the emergence of the first large sedentary civilizations in the Middle East, administrative systems developed specifically around food storage and distribution. The ancient Egyptian...

  1. Net technical assessment

    OpenAIRE

    Wegmann, David G.

    1989-01-01

    Approved for public release; distribution is unlimited. The present and near term military balance of power between the U.S. and the Soviet Union can be expressed in a variety of net assessments. One can examine the strategic nuclear balance, the conventional balance in Europe, the maritime balance, and many others. Such assessments are essential not only for policy making but for arms control purposes and future force structure planning. However, to project the future military balance, on...

  2. Seismic slip recorded in tourmaline fault mirrors from Elba Island (Italy)

    Science.gov (United States)

    Viti, C.; Brogi, A.; Liotta, D.; Mugnaioli, E.; Spiess, R.; Dini, A.; Zucchi, M.; Vannuccini, G.

    2016-05-01

    This paper reports the first example of fault mirrors developed in an unusual protolith, consisting of tourmaline crystals with interstitial goethite. The deformation mechanisms active in the fault zone have been investigated from the outcrop to the nanoscale, aiming to identify possible traces of frictional heating at seismic slip rate, as observed for other fault mirrors in different protoliths. The investigation revealed the superposition of two main deformational stages. The first was dominated by brittle processes and produced a cataclastic/ultracataclastic principal slip zone, a few mm thick; the second was associated with seismic slip and produced a sharp discontinuity (the principal slip surface) within the cataclastic/ultracataclastic zone. The mirror-like coating, a few microns thick, occurs on the principal slip surface, and is characterized by 1) absence of interstitial goethite; 2) occurrence of truncated tourmaline crystals; 3) highly variable grain size, from 200 μm to 200 nm; 4) tourmaline close packing with interlobate grain boundaries, and 5) tourmaline random crystallographic orientation. Micro and nanostructural investigations indicate the occurrence of thermally-activated processes, involving both interstitial goethite and tourmaline. In particular, close to the principal slip surface, goethite is completely decomposed, and produced an amorphous porous material, with local topotactic recrystallization of hematite. Tourmaline clasts are typically characterized by strongly lobate boundaries, indicative of reaction and partial decomposition at grain boundaries. TEM observations revealed the occurrence of tourmaline nanograins, a few tens of nm in size, characterized by rounded shape and fading amorphous boundaries, that cannot be obtained by brittle processes. Lastly, the peculiar interlobate microstructure of the mirror surface is interpreted as the result of grain boundary recrystallization processes taking place by deformation at high

  3. Using WordNet for Building WordNets

    CERN Document Server

    Farreres, X; Farreres, Xavier; Rodriguez, Horacio; Rigau, German

    1998-01-01

    This paper summarises a set of methodologies and techniques for the fast construction of multilingual WordNets. The English WordNet is used in this approach as a backbone for Catalan and Spanish WordNets and as a lexical knowledge resource for several subtasks.

  4. Dislocation pileup as a representation of strain accumulation on a strike-slip fault

    Science.gov (United States)

    Savage, J.C.

    2006-01-01

    The conventional model of strain accumulation on a vertical transform fault is a discrete screw dislocation in an elastic half-space with the Burgers vector of the dislocation increasing at the rate of relative plate motion. It would be more realistic to replace that discrete dislocation by a dislocation distribution, presumably a pileup in which the individual dislocations are in equilibrium. The length of the pileup depends upon the applied stress and the amount of slip that has occurred at depth. I argue here that the dislocation pileup (the transition on the fault from no slip to slip at the full plate rate) occupies a substantial portion of the lithosphere thickness. A discrete dislocation at an adjustable depth can reproduce the surface deformation profile predicted by a pileup so closely that it will be difficult to distinguish between the two models. The locking depth (dislocation depth) of that discrete dislocation approximation is substantially (???30%) larger than that (depth to top of the pileup) in the pileup model. Thus, in inverting surface deformation data using the discrete dislocation model, the locking depth in the model should not be interpreted as the true locking depth. Although dislocation pileup models should provide a good explanation of the surface deformation near the fault trace, that explanation may not be adequate at greater distances from the fault trace because approximating the expected horizontally distributed deformation at subcrustal depths by uniform slip concentrated on the fault is not justified.

  5. Reconciling catch differences from multiple fishery independent gill net surveys

    Science.gov (United States)

    Kraus, Richard T.; Vandergoot, Christopher; Kocovsky, Patrick M.; Rogers, Mark W.; Cook, H. Andrew; Brenden, Travis O.

    2017-01-01

    Fishery independent gill net surveys provide valuable demographic information for population assessment and resource management, but relative to net construction, the effects of ancillary species, and environmental variables on focal species catch rates are poorly understood. In response, we conducted comparative deployments with three unique, inter-agency, survey gill nets used to assess walleye Sander vitreus in Lake Erie. We used an information-theoretic approach with Akaike’s second-order information criterion (AICc) to evaluate linear mixed models of walleye catch as a function of net type (multifilament and two types of monofilament netting), mesh size (categorical), Secchi depth, temperature, water depth, catch of ancillary species, and interactions among selected variables. The model with the greatest weight of evidence showed that walleye catches were positively associated with potential prey and intra-guild predators and negatively associated with water depth and temperature. In addition, the multifilament net had higher average walleye catches than either of the two monofilament nets. Results from this study both help inform decisions about proposed gear changes to stock assessment surveys in Lake Erie, and advance our understanding of how multispecies associations explain variation in gill net catches. Of broader interest to fishery-independent gill net studies, effects of abiotic variables and ancillary species on focal specie’s catch rates were small in comparison with net characteristics of mesh size or twine type.

  6. Closed central slip injuries--a missed diagnosis?

    LENUS (Irish Health Repository)

    Nugent, N

    2011-09-01

    The extensor apparatus of the finger is a complex structure and injury can lead to significant digital dysfunction. Closed central slip injuries may be missed or diagnosis delayed because of lack of an open wound and often no radiographic abnormality, and can result in boutonniere deformities if untreated. This study aimed to quantify the number of patients attending with closed central slip injuries and to ascertain if the initial diagnosis was correct. The number of patients presenting to us over a 6 month period was recorded. The original diagnosis, time to diagnosis of central slip injury and the presence\\/absence of a boutonniere deformity were recorded. Ten patients were included in the study. Seven (70%) injuries were due to sport. Eight (80%) had a delayed diagnosis of central slip injury. Six (60%) had previously presented to general practitioners or emergency departments. Seven (70%) had boutonniere deformities. Closed central slip injuries can be missed. Simple clinical tests can diagnose central slip disruption.

  7. Slipped capital femoral epiphysis: what's new?

    Science.gov (United States)

    Peck, Kathryn; Herrera-Soto, José

    2014-01-01

    Slipped capital femoral epiphysis (SCFE) is a common hip disorder among adolescents, whereby the epiphysis is displaced posteriorly and inferiorly to the metaphysis. Treatment modalities aim to stabilize the epiphysis, prevent further slippage, and avoid complications associated with long-term morbidity, such as osteonecrosis and chondrolysis. Controversy exists with SCFE regarding prophylactic fixation of the contralateral, painless, normal hip, the role of femoroacetabular impingement with SCFE, and whether in situ fixation is the best treatment method for SCFE. This article presents and discusses the latest diagnostic and treatment modalities for SCFE. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Collective Quantum Phase-Slip Dynamics in Superconducting Nanowire Arrays

    Science.gov (United States)

    Skacel, Sebastian T.; Voss, Jan N.; Bier, Tobias; Radke, Lucas; Weides, Martin; Rotzinger, Hannes; Mooij, Hans E.; Ustinov, Alexey V.

    2014-03-01

    Superconducting nanowire arrays exhibit quantum phase-slip (QPS) phenomenon if the superconductor has a very high normal-state sheet resistance. We experimentally study QPS effects in arrays of nanowires embedded in a resonant circuit at GHz frequencies. We probe this circuit at ultra-low microwave power, applied flux and mK temperatures. The nanowires are fabricated utilizing aluminium grown in a precisely-controlled oxygen atmosphere. In this way, we aim to control the QPS rate for a given wire width. The wires are defined with conventional electron beam lithography down to a width of 20 nm. We will present the fabrication of the nanowire arrays and first microwave measurements at mK temperatures. Center for Functional Nanostructures, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany.

  9. Asynchronous slip-ring motor synchronized with permanent magnets

    Directory of Open Access Journals (Sweden)

    Glinka Tadeusz

    2017-03-01

    Full Text Available The electric LSPMSM motor presented in the paper differs from standard induction motor by rotor design. The insulated start-up winding is located in slots along the rotor circumference. The winding ends are connected to the slip-rings. The rotor core contains permanent magnets. The electromechanical characteristics for synchronous operation were calculated, as were the start-up characteristics for operation with a short-circuited rotor winding. Two model motors were used for the calculations, the V-shaped Permanent Magnet (VPM – Fig. 3, and the Linear Permanent Magnet (IPM – Fig. 4, both rated at 14.5 kW. The advantages of the investigated motor are demonstrated in the conclusions.

  10. Correlation between stick-slip frictional sliding and charge transfer

    OpenAIRE

    Ananthakrishna, G.; Kumar, Jagadish

    2010-01-01

    A decade ago, Budakian and Putterman (Phys. Rev. Lett., {\\bf 85}, 1000 (2000)) ascribed friction to the formation of bonds arising from contact charging when a gold tip of a surface force apparatus was dragged on polymethylmethacrylate surface. We propose a stick-slip model that captures the observed correlation between stick-slip events and charge transfer, and the lack of dependence of the scale factor connecting the force jumps and charge transfer on normal load. Here, stick-slip dynamics ...

  11. Proof nets for lingusitic analysis

    NARCIS (Netherlands)

    Moot, R.C.A.

    2002-01-01

    This book investigates the possible linguistic applications of proof nets, redundancy free representations of proofs, which were introduced by Girard for linear logic. We will adapt the notion of proof net to allow the formulation of a proof net calculus which is soundand complete for the

  12. Teaching Tennis for Net Success.

    Science.gov (United States)

    Young, Bryce

    1989-01-01

    A program for teaching tennis to beginners, NET (Net Easy Teaching) is described. The program addresses three common needs shared by tennis students: active involvement in hitting the ball, clearing the net, and positive reinforcement. A sample lesson plan is included. (IAH)

  13. Net4Care Ecosystem Website

    DEFF Research Database (Denmark)

    Christensen, Henrik Bærbak; Hansen, Klaus Marius; Rasmussen, Morten

    2012-01-01

    is a tele-monitoring scenario in which Net4Care clients are deployed in a gateway in private homes. Medical devices then connect to these gateways and transmit their observations to a Net4Care server. In turn the Net4Care server creates valid clinical HL7 documents, stores them in a national XDS repository...

  14. EMG and Kinematic Responses to Unexpected Slips After Slip Training in Virtual Reality

    Science.gov (United States)

    Parijat, Prakriti; Lockhart, Thurmon E.

    2015-01-01

    The objective of the study was to design a virtual reality (VR) training to induce perturbation in older adults similar to a slip and examine the effect of the training on kinematic and muscular responses in older adults. Twenty-four older adults were involved in a laboratory study and randomly assigned to two groups (virtual reality training and control). Both groups went through three sessions including baseline slip, training, and transfer of training on slippery surface. The training group experienced twelve simulated slips using a visual perturbation induced by tilting a virtual reality scene while walking on the treadmill and the control group completed normal walking during the training session. Kinematic, kinetic, and EMG data were collected during all the sessions. Results demonstrated the proactive adjustments such as increased trunk flexion at heel contact after training. Reactive adjustments included reduced time to peak activations of knee flexors, reduced knee coactivation, reduced time to trunk flexion, and reduced trunk angular velocity after training. In conclusion, the study findings indicate that the VR training was able to generate a perturbation in older adults that evoked recovery reactions and such motor skill can be transferred to the actual slip trials. PMID:25296401

  15. Progressive slip after removal of screw fixation in slipped capital femoral epiphysis: two case reports

    NARCIS (Netherlands)

    Engelsma, Y.; Morgenstern, P.; van der Sluijs, J.A.; Witbreuk, M.M.

    2012-01-01

    Introduction. In slipped capital femoral epiphysis the femoral neck displaces relative to the head due to weakening of the epiphysis. Early recognition and adequate surgical fixation is essential for a good functional outcome. The fixation should be secured until the closure of the epiphysis to

  16. Evolution of seismic signals and slip patterns along subduction zones: insights from a friction lab scale experiment

    CERN Document Server

    Voisin, Christophe; Larose, Eric; Renard, François

    2008-01-01

    Continuous GPS and broadband seismic monitoring have revealed a variety of disparate slip patterns especially in shallow dipping subduction zones, among which regular earthquakes, slow slip events and silent quakes1,2. Slow slip events are sometimes accompanied by Non Volcanic Tremors (NVT), which origin remains unclear3, either related to fluid migration or to friction. The present understanding of the whole menagerie of slip patterns is based upon numerical simulations imposing ad hoc values of the rate and state parameters a and b4-6 derived from the temperature dependence of a and b of a wet granite gouge7. Here we investigate the influence of the cumulative slip on the frictional and acoustic patterns of a lab scale subduction zone. Shallow loud earthquakes (stick-slip events), medium depth slow, deeper silent quakes (smooth sliding oscillations) and deepest steady-state creep (continuous sliding) are reproduced by the ageing of contact interface with cumulative displacement8. The Acoustic Emission evolv...

  17. Identifying two regimes of slip of simple fluids over smooth surfaces with weak and strong wall-fluid interaction energies.

    Science.gov (United States)

    Hu, Haibao; Bao, Luyao; Priezjev, Nikolai V; Luo, Kai

    2017-01-21

    The slip behavior of simple fluids over atomically smooth surfaces was investigated in a wide range of wall-fluid interaction (WFI) energies at low shear rates using non-equilibrium molecular dynamics simulations. The relationship between slip and WFI shows two regimes (the strong-WFI and weak-WFI regimes): as WFI decreases, the slip length increases in the strong-WFI regime and decreases in the weak-WFI regime. The critical value of WFI energy that separates these regimes increases with temperature, but it remains unaffected by the driving force. The mechanism of slip was analyzed by examining the density-weighted average energy barrier (ΔE¯) encountered by fluid atoms in the first fluid layer (FFL) during their hopping between minima of the surface potential. We demonstrated that the relationship between slip and WFI can be rationalized by considering the effect of the fluid density distribution in the FFL on ΔE¯ as a function of the WFI energy. Moreover, the dependence of the slip length on WFI and temperature is well correlated with the exponential factor exp(-ΔE¯/(kBT)), which also determines the critical value of WFI between the strong-WFI and weak-WFI regimes.

  18. Stochastic Wheel-Slip Compensation Based Robot Localization and Mapping

    Directory of Open Access Journals (Sweden)

    SIDHARTHAN, R. K.

    2016-05-01

    Full Text Available Wheel slip compensation is vital for building accurate and reliable dead reckoning based robot localization and mapping algorithms. This investigation presents stochastic slip compensation scheme for robot localization and mapping. Main idea of the slip compensation technique is to use wheel-slip data obtained from experiments to model the variations in slip velocity as Gaussian distributions. This leads to a family of models that are switched depending on the input command. To obtain the wheel-slip measurements, experiments are conducted on a wheeled mobile robot and the measurements thus obtained are used to build the Gaussian models. Then the localization and mapping algorithm is tested on an experimental terrain and a new metric called the map spread factor is used to evaluate the ability of the slip compensation technique. Our results clearly indicate that the proposed methodology improves the accuracy by 72.55% for rotation and 66.67% for translation motion as against an uncompensated mapping system. The proposed compensation technique eliminates the need for extro receptive sensors for slip compensation, complex feature extraction and association algorithms. As a result, we obtain a simple slip compensation scheme for localization and mapping.

  19. Prediction of fluid velocity slip at solid surfaces

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; Todd, Billy; Daivis, Peter

    2011-01-01

    The observed flow enhancement in highly confining geometries is believed to be caused by fluid velocity slip at the solid wall surface. Here we present a simple and highly accurate method to predict this slip using equilibrium molecular dynamics. Unlike previous equilibrium molecular dynamics...... methods, it allows us to directly compute the intrinsic wall-fluid friction coefficient rather than an empirical friction coefficient that includes all sources of friction for planar shear flow. The slip length predicted by our method is in excellent agreement with the slip length obtained from direct...

  20. Is the co-seismic slip distribution fractal?

    Science.gov (United States)

    Milliner, Christopher; Sammis, Charles; Allam, Amir; Dolan, James

    2015-04-01

    Co-seismic along-strike slip heterogeneity is widely observed for many surface-rupturing earthquakes as revealed by field and high-resolution geodetic methods. However, this co-seismic slip variability is currently a poorly understood phenomenon. Key unanswered questions include: What are the characteristics and underlying causes of along-strike slip variability? Do the properties of slip variability change from fault-to-fault, along-strike or at different scales? We cross-correlate optical, pre- and post-event air photos using the program COSI-Corr to measure the near-field, surface deformation pattern of the 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine earthquakes in high-resolution. We produce the co-seismic slip profiles of both events from over 1,000 displacement measurements and observe consistent along-strike slip variability. Although the observed slip heterogeneity seems apparently complex and disordered, a spectral analysis reveals that the slip distributions are indeed self-affine fractal i.e., slip exhibits a consistent degree of irregularity at all observable length scales, with a 'short-memory' and is not random. We find a fractal dimension of 1.58 and 1.75 for the Landers and Hector Mine earthquakes, respectively, indicating that slip is more heterogeneous for the Hector Mine event. Fractal slip is consistent with both dynamic and quasi-static numerical simulations that use non-planar faults, which in turn causes heterogeneous along-strike stress, and we attribute the observed fractal slip to fault surfaces of fractal roughness. As fault surfaces are known to smooth over geologic time due to abrasional wear and fracturing, we also test whether the fractal properties of slip distributions alters between earthquakes from immature to mature fault systems. We will present results that test this hypothesis by using the optical image correlation technique to measure historic, co-seismic slip distributions of earthquakes from structurally mature, large

  1. Slipped capital femoral epiphysis: A modern treatment protocol

    Directory of Open Access Journals (Sweden)

    Slavković Nemanja

    2009-01-01

    Full Text Available The treatment of a patient with slipped capital femoral epiphysis begins with an early diagnosis and accurate classification. On the basis of symptom duration, clinical findings and radiographs, slipped capital femoral epiphysis is classified as pre-slip, acute, acute-on-chronic and chronic. The long-term outcome of slipped capital femoral epiphysis is directly related to severity and the presence or absence of avascular necrosis and/or chondrolysis. Therefore, the first priority in the treatment of slipped capital femoral epiphysis is to avoid complications while securing the epiphysis from further slippage. Medical treatment of patients with acute and acute-on-chronic slipped capital femoral epiphysis, as well as those presented in pre-slip stage, is the safest, although time-consuming. Manipulations, especially forced and repeated, are not recommended due to higher avascular necrosis risk. The use of intraoperative fluoroscopy to assist in the placement of internal fixation devices has markedly increased the success of surgical treatment. Controversy remains as to whether the proximal femoral epiphysis in severe, chronic slipped capital femoral epiphysis should be realigned by extracapsular osteotomies or just fixed in situ. The management protocol for slipped capital femoral epiphysis depends on the experience of the surgeon, motivation of the patient and technical facilities.

  2. Master Robotic Net

    Directory of Open Access Journals (Sweden)

    Vladimir Lipunov

    2010-01-01

    Full Text Available The main goal of the MASTER-Net project is to produce a unique fast sky survey with all sky observed over a single night down to a limiting magnitude of 19-20. Such a survey will make it possible to address a number of fundamental problems: search for dark energy via the discovery and photometry of supernovae (including SNIa, search for exoplanets, microlensing effects, discovery of minor bodies in the Solar System, and space-junk monitoring. All MASTER telescopes can be guided by alerts, and we plan to observe prompt optical emission from gamma-ray bursts synchronously in several filters and in several polarization planes.

  3. Art/Net/Work

    DEFF Research Database (Denmark)

    Andersen, Christian Ulrik; Lindstrøm, Hanne

    2006-01-01

    The seminar Art|Net|Work deals with two important changes in our culture. On one side, the network has become essential in the latest technological development. The Internet has entered a new phase, Web 2.0, including the occurrence of as ‘Wiki’s’, ‘Peer-2-Peer’ distribution, user controlled...... the praxis of the artist. We see different kinds of interventions and activism (including ‘hacktivism’) using the network as a way of questioning the invisible rules that govern public and semi-public spaces. Who ‘owns’ them? What kind of social relationships do they generate? On what principle...

  4. Elastic stress transfer as a diffusive process due to aseismic fault slip in response to fluid injection

    Science.gov (United States)

    Viesca, R. C.

    2015-12-01

    Subsurface fluid injection is often followed by observations of an enlarging cloud of microseismicity. The cloud's diffusive growth is thought to be a direct response to the diffusion of elevated pore fluid pressure reaching pre-stressed faults, triggering small instabilities; the observed high rates of this growth are interpreted to reflect a relatively high permeability of a fractured subsurface [e.g., Shapiro, GJI 1997]. We investigate an alternative mechanism for growing a microseismic cloud: the elastic transfer of stress due to slow, aseismic slip on a subset of the pre-existing faults in this damaged subsurface. We show that the growth of the slipping region of the fault may be self-similar in a diffusive manner. While this slip is driven by fluid injection, we show that, for critically stressed faults, the apparent diffusion of this slow slip may quickly exceed the poroelastically driven diffusion of the elevated pore fluid pressure. Under these conditions, microseismicity can be first triggered by the off-fault stress perturbation due to the expanding region of slip on principal faults. This provides an alternative interpretation of diffusive growth rates in terms of the subsurface stress state rather than an enhanced hydraulic diffusivity. That such aseismic slip may occur, outpace fluid diffusion, and in turn trigger microseismic events, is also suggested by on- and near-fault observations in past and recently reported fluid injection experiments [e.g., Cornet et al., PAGEOPH 1997; Guglielmi et al., Science 2015]. The model of injection-induced slip assumes elastic off-fault behavior and a fault strength determined by the product of a constant friction coefficient and the local effective normal stress. The sliding region is enlarged by the pore pressure increase resolved on the fault plane. Remarkably, the rate of self-similar expansion may be determined by a single parameter reflecting both the initial stress state and the magnitude of the pore pressure

  5. Slipped Capital Femoral Epiphysis: Diagnosis and Management.

    Science.gov (United States)

    Peck, David M; Voss, Lisa M; Voss, Tyler T

    2017-06-15

    Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in adolescents, occurring in 10.8 per 100,000 children. SCFE usually occurs in those eight to 15 years of age and is one of the most commonly missed diagnoses in children. SCFE is classified as stable or unstable based on the stability of the physis. It is associated with obesity, growth spurts, and (occasionally) endocrine abnormalities such as hypothyroidism, growth hormone supplementation, hypogonadism, and panhypopituitarism. Patients with SCFE usually present with limping and poorly localized pain in the hip, groin, thigh, or knee. Diagnosis is confirmed by bilateral hip radiography, which should include anteroposterior and frog-leg views in patients with stable SCFE, and anteroposterior and cross-table lateral views in unstable SCFE. The goals of treatment are to prevent slip progression and avoid complications such as avascular necrosis, chondrolysis, and femoroacetabular impingement. Stable SCFE is usually treated using in situ screw fixation. Treatment of unstable SCFE also usually involves in situ fixation, but there is controversy about timing of surgery and the value of reduction. Postoperative rehabilitation of patients with SCFE may follow a five-phase protocol.

  6. Helminth.net: expansions to Nematode.net and an introduction to Trematode.net

    Science.gov (United States)

    Martin, John; Rosa, Bruce A.; Ozersky, Philip; Hallsworth-Pepin, Kymberlie; Zhang, Xu; Bhonagiri-Palsikar, Veena; Tyagi, Rahul; Wang, Qi; Choi, Young-Jun; Gao, Xin; McNulty, Samantha N.; Brindley, Paul J.; Mitreva, Makedonka

    2015-01-01

    Helminth.net (http://www.helminth.net) is the new moniker for a collection of databases: Nematode.net and Trematode.net. Within this collection we provide services and resources for parasitic roundworms (nematodes) and flatworms (trematodes), collectively known as helminths. For over a decade we have provided resources for studying nematodes via our veteran site Nematode.net (http://nematode.net). In this article, (i) we provide an update on the expansions of Nematode.net that hosts omics data from 84 species and provides advanced search tools to the broad scientific community so that data can be mined in a useful and user-friendly manner and (ii) we introduce Trematode.net, a site dedicated to the dissemination of data from flukes, flatworm parasites of the class Trematoda, phylum Platyhelminthes. Trematode.net is an independent component of Helminth.net and currently hosts data from 16 species, with information ranging from genomic, functional genomic data, enzymatic pathway utilization to microbiome changes associated with helminth infections. The databases’ interface, with a sophisticated query engine as a backbone, is intended to allow users to search for multi-factorial combinations of species’ omics properties. This report describes updates to Nematode.net since its last description in NAR, 2012, and also introduces and presents its new sibling site, Trematode.net. PMID:25392426

  7. The Employment Guarantee Scheme as a Social Safety Net - Poverty Dynamics and Poverty Alleviation

    OpenAIRE

    Katsushi Imai

    2003-01-01

    This paper investigates the dynamic aspects of poverty and anti-poverty interventions, particularly focusing on promotional effects, i.e., the effects of helping the poor escape poverty and protective effects, i.e., the effects of preventing the non-poor from slipping into poverty. We test the effectiveness of the Employment Guarantee Scheme (EGS) in rural India as a social safety net drawing upon the ICRISAT survey data. We have carried out the econometric analysis, namely Cox Proportional H...

  8. Utilization of insecticide treated nets in Arbaminch Town and the ...

    African Journals Online (AJOL)

    Bernt Lindtjorn

    using structured, pretested, interviewer-administered questionnaire. Data entry and analysis was performed using SPSS. 11.0 for windows. Univariate, bivariate and multivariate analyses were carried out. Results: The coverage for any net and ITN was 75.1% and 58.8% respectively; the utilization rate for any net and ITN.

  9. The nucleation of "fast" and "slow" stick slip instabilities in sheared granular aggregates

    Science.gov (United States)

    Korkolis, Evangelos; Ampuero, Jean-Paul; Niemeijer, André

    2017-04-01

    Seismological observations in the past few decades have revealed a diversity of slip behaviors of faults, involving interactions and transition between slow to fast slip phenomena. Field studies show that exhumed fault zones comprise mixtures of materials with variable frictional strength and stability. Emergent models of slip diversity emphasize the role of heterogeneities of fault zone properties and the potential interactions between seismic and aseismic deformation. Here, we develop analog laboratory experiments to study the mechanics of heterogeneous faults with the goal to identify factors controlling their slip stability and rupture style. We report on results from room temperature sliding experiments using a rotary shear apparatus. We simulated gouge heterogeneity by using materials with different frictional strength and stability. At room temperature conditions, dry glass beads typically stick slip, whereas dry granular calcite exhibits stable sliding. The peak strength of glass beads aggregates is typically lower than that of granular calcite aggregates. Our samples consisted of a layer of glass beads sandwiched between two layers of granular calcite. The initial particle size was between 100 and 200 μm for both materials and the initial thickness of each layer was about 1.5 mm. We tested our layered aggregates under 1 to 7 MPa normal stress and at sliding velocities between 1 and 100 μm/s. Within that range of conditions, high normal stress and slow sliding velocities promoted fast, regular stick slip. For normal stress values of less than about 4 MPa, the recurrence time and stress drop of stick slips became irregular, particularly at sliding rates above 20 μm/s. As the accumulated shear displacement increased, slip events became slower and the magnitudes of their stress drop, compaction and slip distance decreased. We recorded acoustic emissions (AEs) associated with each slip event (fast and slow) and estimated their source azimuth. AE activity was

  10. Dynamic growth of slip surfaces in catastrophic landslides.

    Science.gov (United States)

    Germanovich, Leonid N; Kim, Sihyun; Puzrin, Alexander M

    2016-01-01

    This work considers a landslide caused by the shear band that emerges along the potential slip (rupture) surface. The material above the band slides downwards, causing the band to grow along the slope. This growth may first be stable (progressive), but eventually becomes dynamic (catastrophic). The landslide body acquires a finite velocity before it separates from the substrata. The corresponding initial-boundary value problem for a dynamic shear band is formulated within the framework of Palmer & Rice's (Proc. R. Soc. Lond. A332, 527-548. (doi:10.1098/rspa.1973.0040)) approach, which is generalized to the dynamic case. We obtain the exact, closed-form solution for the band velocity and slip rate. This solution assesses when the slope fails owing to a limiting condition near the propagating tip of the shear band. Our results are applicable to both submarine and subaerial landslides of this type. It appears that neglecting dynamic (inertia) effects can lead to a significant underestimation of the slide size, and that the volumes of catastrophic slides can exceed the volumes of progressive slides by nearly a factor of 2. As examples, we consider the Gaviota and Humboldt slides offshore of California, and discuss landslides in normally consolidated sediments and sensitive clays. In particular, it is conceivable that Humboldt slide is unfinished and may still displace a large volume of sediments, which could generate a considerable tsunami. We show that in the case of submarine slides, the effect of water resistance on the shear band dynamics may frequently be limited during the slope failure stage. For a varying slope angle, we formulate a condition of slide cessation.

  11. The equivalency between logic Petri workflow nets and workflow nets.

    Science.gov (United States)

    Wang, Jing; Yu, ShuXia; Du, YuYue

    2015-01-01

    Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented.

  12. Quasi-periodic slow slip events in the afterslip area of the 1996 Hyuga-nada earthquakes, Japan

    Science.gov (United States)

    Yarai, Hiroshi; Ozawa, Shinzaburo

    2013-05-01

    The time evolution of afterslip on a plate boundary experiencing interplate earthquakes is expected to show logarithmic decay. The global positioning system network in Japan has been monitoring transient deformation since the occurrence of two large interplate earthquakes with moment magnitudes of 6.8 and 6.7 in the Hyuga-nada area, southwest Japan, in 1996. The spatial and temporal evolution of aseismic interplate slip based on crustal deformation data indicates that afterslip followed the two earthquakes and gradually declined to background rates by around 2004 with total moment magnitude of 7.3. However, quasi-periodic slow slip events suddenly began within the afterslip area in 2005 with approximately one year duration and two-year recurrence interval. The moment magnitudes of the three slow slip events since January 2005 range from 6.7 to 6.8. This differs greatly from the expected behavior of logarithmic decay over time. Both velocity-strengthening and velocity-weakening rate-and-state modes have been implicated as the cause of afterslip, whose location is complementary to the main shock area of velocity-weakening, while a slow slip event occurs in the velocity-weakening area with different frictional properties from those of an afterslip area. In light of the seemingly different frictional properties, the coexistence of afterslip and slow slip events in the same area would provide additional information about precisely how the plate interface is behaving. The monitoring of these slow slip events should give the clues to understanding the coexistence of long-term afterslip and slow slip events and the increasing risk of earthquakes in neighboring areas.

  13. The No-Slip Boundary Condition in Fluid Mechanics

    Indian Academy of Sciences (India)

    gradient near a wall have to satisfy the no-slip condition at every instant. ... The well known Bernoulli equation giving a relation .... resistance being proportional to the slip velocity itself. leads to infinite stress. But this model was proposed before the. N-S equations were known. The third hypothesis was due to Navier himself.

  14. Stokes flow with slip and Kuwabara boundary conditions

    Indian Academy of Sciences (India)

    ... distributed parallel circular cylinder or spheres in uniform viscous flow are investigated with slip boundary condition under Stokes approximation using particle-in-cell model technique and the result compared with the no-slip case. The corresponding problem of streaming flow past spheroidal particles departing but little in ...

  15. A Transformational Approach to Slip-Slide Factoring

    Science.gov (United States)

    Steckroth, Jeffrey

    2015-01-01

    In this "Delving Deeper" article, the author introduces the slip-slide method for solving Algebra 1 mathematics problems. This article compares the traditional method approach of trial and error to the slip-slide method of factoring. Tools that used to be taken for granted now make it possible to investigate relationships visually,…

  16. Performance analysis of a microcontroller based slip power recovery ...

    African Journals Online (AJOL)

    user

    International Journal of Engineering, Science and Technology ... Keywords: Slip power recovery drive; simulation; experiment; speed control. 1. Introduction ... rotor side converter, inverter and transformer circuit in SPRD is designed to be smaller, ... Akpinar and Pillai, 1990 proposed modeling and performance of slip power.

  17. Multiparameter Monitoring and Prevention of Fault-Slip Rock Burst

    Directory of Open Access Journals (Sweden)

    Shan-chao Hu

    2017-01-01

    Full Text Available Fault-slip rock burst is one type of the tectonic rock burst during mining. A detailed understanding of the precursory information of fault-slip rock burst and implementation of monitoring and early warning systems, as well as pressure relief measures, are essential to safety production in deep mines. This paper first establishes a mechanical model of stick-slip instability in fault-slip rock bursts and then reveals the failure characteristics of the instability. Then, change rule of mining-induced stress and microseismic signals before the occurrence of fault-slip rock burst are proposed, and multiparameter integrated early warning methods including mining-induced stress and energy are established. Finally, pressure relief methods targeting large-diameter boreholes and coal seam infusion are presented in accordance with the occurrence mechanism of fault-slip rock burst. The research results have been successfully applied in working faces 2310 of the Suncun Coal Mine, and the safety of the mine has been enhanced. These research results improve the theory of fault-slip rock burst mechanisms and provide the basis for prediction and forecasting, as well as pressure relief, of fault-slip rock bursts.

  18. Three cases of slipped capital femoral epiphysis in one family.

    Science.gov (United States)

    Skelley, Nathan W; Papp, Derek F; Leu, Dirk; Sargent, M Catherine

    2011-08-08

    Slipped capital femoral epiphysis is a relatively common disorder of the hip that affects children in late childhood and early adolescence, with an incidence in the United States of approximately 10 per 100,000. Although the diagnosis and treatment of slipped capital femoral epiphysis have been well described, the search for its cause and a method of early identification continues. Recent publications have suggested that there is a familial association among individuals with slipped capital femoral epiphysis, but there is no current genetic marker established for the disorder. This article reports a series of 3 biologically related Caucasian sisters who were athletic; had body mass indices slipped capital femoral epiphysis. This is the first report of a series of 3 sisters with slipped capital femoral epiphysis in the United States. Our goals were to document our experience in the identification and treatment of these patients to highlight the complexities of slipped capital femoral epiphysis presentation patterning, to increase the awareness and reporting of familial cases of slipped capital femoral epiphysis by other physicians, and to encourage additional research in this area. As clinicians progress in the ability to diagnose and treat patients with slipped capital femoral epiphysis, they also must be mindful of the varying presentation characteristics. Copyright 2011, SLACK Incorporated.

  19. Stability Analysis of Static Slip-Energy Recovery Drive via ...

    African Journals Online (AJOL)

    The stability of the sub synchronous static slip energy recovery scheme for the speed control of slip-ring induction motor is presented. A set of nonlinear differential equations which describe the system dynamics are derived and linearized about an operating point using perturbation technique. The Eigenvalue analysis of the ...

  20. Slip casting parameters for commercial Si3N4 powders

    OpenAIRE

    Hartmann, WJAM; Dijen, van, FK Frans; Metselaar, R Ruud; Siskens, CAM Carol

    1986-01-01

    Properties of aqueous slips of silicon nitride were studied on two types of commercially available powders. Results are given of measurements of ζ-potential, critical coagulation coefficient and viscosity as a function of pH, concentration of deflocculant and solid-liquid ratio. Optimized slip casting conditions are given.

  1. Fabric evolution of quartz-gouge from stable sliding to stick-slip and implications for fault slip mode

    Science.gov (United States)

    Scuderi, Marco; Collettini, Cristiano; Viti, Cecilia; Tinti, Elisa; Marone, Chris

    2017-04-01

    Numerous laboratory studies have documented the mechanisms that control the earthquake nucleation phase, when fault slip velocity is slow (1 cm/s). Although these studies are fundamental to characterize specific phases of the seismic cycle, they are not able of capturing the entire evolution of fabric and mechanical data from stable sliding to stick-slip. Here we report on laboratory experiments that illuminate the mechanisms controlling the transition from stable sliding (v= 0.001 cm/s) to dynamic stick-slip (v > 1 cm/s), by altering the elastic stiffness of the loading system (k) to match the critical rheologic stiffness of the fault gouge (kc). In particular we observe that the stiffness ratio, K = kc/k, controls the transition from slow-and-silent (K = 0.9, slip velocity 0.01 cm/s, stress drop 0.5 MPa, slip duration 0.5 s) to fast-and-audible (K = 0.5, slip velocity 3 cm/s, stress drop 2.4 MPa, slip duration 0.003 s) slip events. Microstructural observations show that with accumulated strain, deformation localizes along sharp shear planes consisting of nano-metric grains, which favour the development of frictional instabilities. Once this fabric is established, for the tested boundary conditions (normal stress 13-35 MPa), fault fabric does not change significantly with slip velocity, and fault slip behaviour is mainly controlled by the interplay between fault rheological properties and the stiffness of the loading system. As applied to tectonic faults, our results suggest that a single fault segment can experience a spectrum of fault slip behaviour depending on the evolution of fault rock frictional properties and elastic conditions of the loading system.

  2. Microscopic origin of wall slip during flow of an entangled DNA solution in microfluidics: Flow induced chain stretching versus chain desorption.

    Science.gov (United States)

    Hemminger, Orin; Boukany, Pouyan E

    2017-07-01

    Despite the relevance and importance of slip, a fundamental understanding of the underlying molecular mechanisms of wall slip in polymer flow is still missing. In this work, we investigate the slip behavior of an entangled DNA solution at a molecular scale using a confocal microscope coupled to a microfluidic device. From microscopic measurement, we obtain both the velocity profile and conformation of polymeric chains by visualizing DNA molecules during flow on various surfaces (ranging from weak to strong interactions with DNA molecules). In channel flow at a low Weissenberg number (Wi = 0.14), we observe a parabolic flow for an APTES-treated glass (with strong interaction with DNA) in the absence of slip, while a significant amount of slip has been observed for a regular glass (with a weak interaction with DNA). At higher flow rates (Wi > 1.0), strong slip appears during flow on APTES-treated surfaces. In this case, only immobile DNA molecules are stretched on the surface and other bulk chains remain coiled. This observation suggests that the flow induced chain stretching at the interface is the main mechanism of slip during flow on strong surfaces. Conversely, for slip flow on surfaces with weak interactions (such as unmodified or acrylate-modified glasses), polymeric chains are desorbed from the surface and a thin layer of water is present near the surface, which induces an effective slip during flow. By imaging DNA conformations during both channel and shear flows on different surfaces, we elucidate that either chain desorption or flow-induced stretching of adsorbed chains occurs depending on the surface condition. In general, we expect that these new insights into the slip phenomenon will be useful for studying the biological flow involving single DNA molecule experiments in micro/nanofluidic devices.

  3. Coloured Petri Nets

    DEFF Research Database (Denmark)

    Jensen, Kurt; Kristensen, Lars Michael

    studies that illustrate the practical use of CPN modelling and validation for design, specification, simulation, verification and implementation in various application domains. Their presentation primarily aims at readers interested in the practical use of CPN. Thus all concepts and constructs are first......Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. The development of such systems is particularly challenging because of inherent intricacies like possible nondeterminism...... and the immense number of possible execution sequences. In this textbook, Jensen and Kristensen introduce the constructs of the CPN modelling language and present the related analysis methods in detail. They also provide a comprehensive road map for the practical use of CPN by showcasing selected industrial case...

  4. Slipping and rolling on an inclined plane

    Energy Technology Data Exchange (ETDEWEB)

    Aghamohammadi, Cina [Department of Electrical Engineering, Sharif University of Technology, PO Box 11365-11155, Tehran (Iran, Islamic Republic of); Aghamohammadi, Amir, E-mail: mohamadi@alzahra.ac.ir [Department of Physics, Alzahra University, Tehran 19938-91176 (Iran, Islamic Republic of)

    2011-07-15

    In the first part of the paper, using a direct calculation two-dimensional motion of a particle sliding on an inclined plane is investigated for general values of friction coefficient ({mu}). A parametric equation for the trajectory of the particle is also obtained. In the second part of the paper, the motion of a sphere on the inclined plane is studied. It is shown that the evolution equation for the contact point of a sliding sphere is similar to that of a point particle sliding on an inclined plane whose friction coefficient is 7/2 {mu}. If {mu} > 2/7 tan {theta}, for any arbitrary initial velocity and angular velocity, the sphere will roll on the inclined plane after some finite time. In other cases, it will slip on the inclined plane. In the case of rolling, the centre of the sphere moves on a parabola. Finally the velocity and angular velocity of the sphere are exactly computed.

  5. Stick-slip substructure in rapid tape peeling

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2010-10-15

    The peeling of adhesive tape is known to proceed with a stick-slip mechanism and produces a characteristic ripping sound. The peeling also produces light and when peeled in a vacuum, even X-rays have been observed, whose emissions are correlated with the slip events. Here we present direct imaging of the detachment zone when Scotch tape is peeled off at high speed from a solid surface, revealing a highly regular substructure, during the slip phase. The typical 4-mm-long slip region has a regular substructure of transverse 220 μm wide slip bands, which fracture sideways at speeds over 300 m/s. The fracture tip emits waves into the detached section of the tape at ∼100 m/s, which promotes the sound, so characteristic of this phenomenon.

  6. Stochastic stick-slip nanoscale friction on oxide surfaces

    Science.gov (United States)

    Craciun, A. D.; Gallani, J. L.; Rastei, M. V.

    2016-02-01

    The force needed to move a nanometer-scale contact on various oxide surfaces has been studied using an atomic force microscope and theoretical modeling. Force-distance traces unveil a stick-slip movement with erratic slip events separated by several nanometers. A linear scaling of friction force with normal load along with low pull-off forces reveals dispersive adhesive interactions at the interface. We model our findings by considering a variable Lennard-Jones-like interaction potential, which accounts for slip-induced variation of the effective contact area. The model explains the formation and fluctuation of stick-slip phases and provides guidelines for predicting transitions from stick-slip to continuous sliding on oxide surfaces.

  7. Proposed Cavity for Reduced Slip-Stacking Loss

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, J. [Indiana U.; Zwaska, R. [Fermilab

    2015-06-01

    This paper employs a novel dynamical mechanism to improve the performance of slip-stacking. Slip-stacking in an accumulation technique used at Fermilab since 2004 which nearly double the proton intensity. During slip-stacking, the Recycler or the Main Injector stores two particles beams that spatially overlap but have different momenta. The two particle beams are longitudinally focused by two 53 MHz 100 kV RF cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV RF cavity, with a frequency at the double the average of the upper and lower main RF frequencies. In simulation, we find the proposed RF cavity significantly enhances the stable bucket area and reduces slip-stacking losses under reasonable injection scenarios. We quantify and map the stability of the parameter space for any accelerator implementing slip-stacking with the addition of a harmonic RF cavity.

  8. Continued growth after fixation of slipped capital femoral epiphysis.

    Science.gov (United States)

    Holmdahl, Per; Backteman, Torsten; Danielsson, Aina; Kärrholm, Johan; Riad, Jacques

    2016-12-01

    When treating slipped capital femoral epiphysis (SCFE), a smooth pin with a hook or a short threaded screw can be used to allow further growth, which could be important to prevent the development of impingement and early arthritis. The purpose of this investigation was to measure growth in three dimensions after fixation of SCFE. Sixteen participants with unilateral SCFE, nine girls and seven boys with a median age of 12.0 years (range 8.4-15.7 years), were included. The slipped hip was fixed with a smooth pin with a hook, and the non-slipped hip was prophylactically pinned. At the time of surgery, tantalum markers were installed bilaterally on each side of the growth plate through the drilled hole for the pin. Examination with radiostereometric analysis (RSA) was performed postoperatively and at 3, 6 and 12 months. The position of the epiphysis in relation to the metaphysis was calculated. At 12 months, the epiphysis moved caudally, median 0.16 mm and posteriorly 2.28 mm on the slipped side, in comparison to 2.28 cranially and 0.91 mm posteriorly on the non-slipped side, p = 0.003 and p = 0.030, respectively. Both slipped and non-slipped epiphysis moved medially, 1.52 and 1.74 mm, respectively. A marked variation in the movement was noted, especially on the slipped side. The epiphysis moved in relation to the metaphysis after smooth pin fixation, both on the slipped side and on the prophylactically fixed non-slipped side, implying further growth. The RSA method can be used to understand remodelling after 'growth-sparing' fixation of SCFE.

  9. Slow Slip in the Alaska Subduction Zone and the Long-term Slip Budget on the Megathrust

    Science.gov (United States)

    Freymueller, J. T.; Li, S.; Fu, Y.; McCaffrey, R.

    2016-12-01

    The Cook Inlet region of Alaska has experienced some of the longest-lasting slow slip events yet discovered, with the longest event being at least 9 years long and having a moment equivalent to an Mw7.8 earthquake. Three other long-lasting events have been identified as well, with durations ranging from 2-4 years. Small and short-lived events (roughly comparable to some of the Cascadia ETS events) are also seen in the geodetic time series. Based on the record so far, the large slow slip events may be confined to certain segments of the plate interface, although data coverage is not as good or as comprehensive in time. At least one event occurred near Kodiak Island, but other segments of the subduction zone may not have experienced any significant slip events over the last two decades. Within the rupture zone of the 1964 Alaska earthquake, the area experiencing slow slip events overlaps with the area that experienced afterslip following the earthquake. Within uncertainty (which is considerable), there is no evidence for overlap between areas of significant coseismic slip and the areas of the slow slip events. Published papers on the various slow slip events have used different geometric models for the plate interface, which contributes to the present uncertainty in constraining the slip budget.

  10. Lateral traction of laminar flow between sliding pair with heterogeneous slip/no-slip surface

    Science.gov (United States)

    Wu, Zhenpeng; Zeng, Liangcai; Chen, Xiaolan; Chen, Keying; Ding, Xianzhong

    2017-11-01

    The problem of shaft axial motion which significantly affects the lubrication performance has been a common phenomenon in journal bearing systems. The existing work involved in the solution of shaft axial motion is also very rare. In this study, we choose to examine the flow between sliding pair in which regard we present a unique heterogeneous surface consisting of a slip zone and a no-slip zone. The results reveal the following points: 1) By appropriately arranging the slip zone to change the angle between the borderline and the moving direction of the upper plate, it is possible to control the direction of the lateral traction in which the liquid film acts on the upper plate. 2) Exponent of the power function of the borderline and aspect ratio of the computational domain are large or small are not conducive to increasing the effect of lateral traction. For the object of this study, the final results of the optimization are shown that the lateral traction can account for 20% of the resistance.

  11. PROCESSING OF CONCENTRATED AQUEOUS ZIRCONIA-BIOGLASS SLIPS BY SLIP CASTING

    Directory of Open Access Journals (Sweden)

    Beltina Leon

    2017-03-01

    Full Text Available 3 mol% yttria-partially stabilized zirconia (Y-TZP powder and a sol-gel derived CaO- P₂O₅- SiO₂ (64S bioglass, were used to produce Y-TZP- bioglass slip cast compacts. The rheological properties of concentrated aqueous Y-TZP- 64S suspensions prepared with two different glass contents: 10.5 vol% and 19.9 vol%, and ammonium polyacrylate (NH₄PA as dispersant, were investigated and compared with those of Y-TZP. The density of green cast samples was related to the degree of slip dispersion. The substitution of Y-TZP by 64S glass in the mixtures resulted in greater adsorption of NH₄PA; however, the viscosity and yield stress values of Y-TZP-64S slips were higher than those of Y-TZP ones for the solid loadings studied. The increase in the glass content from 10.5 to 19.9 vol% increased the viscosity and yield stress values. The presence of 64S glass in the mixtures resulted in a less dense packing of cast samples.

  12. Contact line motion in confined liquid–gas systems: Slip versus phase transition

    KAUST Repository

    Xu, Xinpeng

    2010-11-30

    In two-phase flows, the interface intervening between the two fluid phases intersects the solid wall at the contact line. A classical problem in continuum fluid mechanics is the incompatibility between the moving contact line and the no-slip boundary condition, as the latter leads to a nonintegrable stress singularity. Recently, various diffuse-interface models have been proposed to explain the contact line motion using mechanisms missing from the sharp-interface treatments in fluid mechanics. In one-component two-phase (liquid–gas) systems, the contact line can move through the mass transport across the interface while in two-component (binary) fluids, the contact line can move through diffusive transport across the interface. While these mechanisms alone suffice to remove the stress singularity, the role of fluid slip at solid surface needs to be taken into account as well. In this paper, we apply the diffuse-interface modeling to the study of contact line motion in one-component liquid–gas systems, with the fluid slip fully taken into account. The dynamic van der Waals theory has been presented for one-component fluids, capable of describing the two-phase hydrodynamics involving the liquid–gas transition [A. Onuki, Phys. Rev. E 75, 036304 (2007)]. This theory assumes the local equilibrium condition at the solid surface for density and also the no-slip boundary condition for velocity. We use its hydrodynamicequations to describe the continuum hydrodynamics in the bulk region and derive the more general boundary conditions by introducing additional dissipative processes at the fluid–solid interface. The positive definiteness of entropy production rate is the guiding principle of our derivation. Numerical simulations based on a finite-difference algorithm have been carried out to investigate the dynamic effects of the newly derived boundary conditions, showing that the contact line can move through both phase transition and slip, with their relative

  13. Genetic and epigenetic drivers of neuroendocrine tumours (NET).

    Science.gov (United States)

    Di Domenico, Annunziata; Wiedmer, Tabea; Marinoni, Ilaria; Perren, Aurel

    2017-09-01

    Neuroendocrine tumours (NET) of the gastrointestinal tract and the lung are a rare and heterogeneous group of tumours. The molecular characterization and the clinical classification of these tumours have been evolving slowly and show differences according to organs of origin. Novel technologies such as next-generation sequencing revealed new molecular aspects of NET over the last years. Notably, whole-exome/genome sequencing (WES/WGS) approaches underlined the very low mutation rate of well-differentiated NET of all organs compared to other malignancies, while the engagement of epigenetic changes in driving NET evolution is emerging. Indeed, mutations in genes encoding for proteins directly involved in chromatin remodelling, such as DAXX and ATRX are a frequent event in NET. Epigenetic changes are reversible and targetable; therefore, an attractive target for treatment. The discovery of the mechanisms underlying the epigenetic changes and the implication on gene and miRNA expression in the different subgroups of NET may represent a crucial change in the diagnosis of this disease, reveal new therapy targets and identify predictive markers. Molecular profiles derived from omics data including DNA mutation, methylation, gene and miRNA expression have already shown promising results in distinguishing clinically and molecularly different subtypes of NET. In this review, we recapitulate the major genetic and epigenetic characteristics of pancreatic, lung and small intestinal NET and the affected pathways. We also discuss potential epigenetic mechanisms leading to NET development. © 2017 Society for Endocrinology.

  14. Fishing with bed nets on Lake Tanganyika: a randomized survey.

    Science.gov (United States)

    McLean, Kate A; Byanaku, Aisha; Kubikonse, Augustine; Tshowe, Vincent; Katensi, Said; Lehman, Amy G

    2014-10-07

    Malaria is among the most common causes of death along Lake Tanganyika, a problem which many aid organizations have attempted to combat through the distribution of free mosquito bed nets to high-risk communities. The Lake Tanganyika Floating Health Clinic (LTFHC), a health-based non-governmental organization (NGO), has observed residents of the Lake Tanganyika basin using bed nets to fish small fry near the shoreline, despite a series of laws that prohibit bed net use and other fine-gauge nets for fishing, implemented to protect the near-shore fish ecology. The LTFHC sought to quantify the sources of bed nets and whether they were being used for fishing. The LTFHC conducted a survey of seven lakeside villages in Lagosa Ward, Tanzania. The government has divided each village into two to six pre-existing geographic sub-villages depending on population size. Seven households per sub-village were chosen at random for survey administration. The survey consisted of 23 questions regarding mosquito bed net practices, including the use of bed nets for fishing, as well as questions pertaining to any perceived changes to the fish supply. A total of 196 surveys were administered over a four-week period with a 100% response rate. Over 87% of households surveyed have used a mosquito bed net for fishing at some point. The majority of respondents reported receiving their bed net for free (96.4%), observing "many" residents of their village using bed nets for fishing (97.4%), and noticing a subjective decrease in the fish supply over time (64.9%). The findings of this study raise concerns that the use of free malaria bed nets for fishing is widespread along Lake Tanganyika, and that this dynamic will have an adverse effect on fish ecology. Further studies are indicated to fully define the scope of bed net misuse and the effects of alternative vector control strategies in water-based communities.

  15. Factors associated with worker slipping in limited-service restaurants.

    Science.gov (United States)

    Courtney, Theodore K; Verma, Santosh K; Huang, Yueng-Hsiang; Chang, Wen-Ruey; Li, Kai Way; Filiaggi, Alfred J

    2010-02-01

    Slips, trips and falls (STF) are responsible for a substantial injury burden in the global workplace. Restaurant environments are challenged by STF. This study assessed individual and work environment factors related to slipping in US limited-service restaurant workers. Workers in 10 limited-service restaurants in Massachusetts were recruited to participate. Workers' occupational slip and/or fall history within the past 4 weeks was collected by multilingual written questionnaires. Age, gender, job tenure, work hours per week and work shift were also collected. Shoe type, condition and gross shoe contamination were visually assessed. Floor friction was measured and each restaurant's overall mean coefficient of friction (COF) was calculated. The logistic generalised estimating equations model was used to compute adjusted odds ratios (OR). Of 125 workers, 42 reported one or more slips in the past 4 weeks with two reporting a resultant fall. Results from multivariable regression showed that higher restaurant mean COF was significantly associated with a decreased risk of self-reported slipping (OR 0.59, 95% CI 0.42 to 0.82). From the highest to the lowest COF restaurant, the odds of a positive slip history increased by a factor of more than seven. Younger age, male gender, lower weekly work hours and the presence of gross contamination on worker's shoe sole were also associated with increased odds of slip history. Published findings of an association between friction and slipping and falling in actual work environments are rare. The findings suggest that effective intervention strategies to reduce the risk of slips and falls in restaurant workers could include increasing COF and improving housekeeping practices.

  16. Linear Logic on Petri Nets

    DEFF Research Database (Denmark)

    Engberg, Uffe Henrik; Winskel, Glynn

    This article shows how individual Petri nets form models of Girard's intuitionistic linear logic. It explores questions of expressiveness and completeness of linear logic with respect to this interpretation. An aim is to use Petri nets to give an understanding of linear logic and give some apprai...

  17. Reference Guide Microsoft.NET

    NARCIS (Netherlands)

    Zee M van der; Verspaij GJ; Rosbergen S; IMP; NMD

    2003-01-01

    Developers, administrators and managers can get more understanding of the .NET technology with this report. They can also make better choices how to use this technology. The report describes the results and conclusions of a study of the usability for the RIVM of this new generation .NET development

  18. Net neutrality and audiovisual services

    NARCIS (Netherlands)

    van Eijk, N.; Nikoltchev, S.

    2011-01-01

    Net neutrality is high on the European agenda. New regulations for the communication sector provide a legal framework for net neutrality and need to be implemented on both a European and a national level. The key element is not just about blocking or slowing down traffic across communication

  19. Numerical Simulation of Methane Slip in Dual Fuel Marine Engines

    DEFF Research Database (Denmark)

    Han, Jaehyun; Jensen, Michael Vincent; Pang, Kar Mun

    and the valve timings on the methane slip was investigated. MAN L28/32DF engine was modeled to simulate the gas exchange process of the four stroke NG-diesel dual fuel engines. The mesh size of the model was decided based on the sensitivity study on the peak pressure of the cylinder and the fuel mass......The methane slip is the problematic issue for the engines using natural gas(NG). Because methane is more powerful greenhouse gas (GHG) than CO2, understanding of the methane slip during gas exchange process of the engines is essential. In this study, the influence of the gas pipe geometry...

  20. A Small Universal Petri Net

    Directory of Open Access Journals (Sweden)

    Dmitry A. Zaitsev

    2013-09-01

    Full Text Available A universal deterministic inhibitor Petri net with 14 places, 29 transitions and 138 arcs was constructed via simulation of Neary and Woods' weakly universal Turing machine with 2 states and 4 symbols; the total time complexity is exponential in the running time of their weak machine. To simulate the blank words of the weakly universal Turing machine, a couple of dedicated transitions insert their codes when reaching edges of the working zone. To complete a chain of a given Petri net encoding to be executed by the universal Petri net, a translation of a bi-tag system into a Turing machine was constructed. The constructed Petri net is universal in the standard sense; a weaker form of universality for Petri nets was not introduced in this work.

  1. Effects of vibration training in reducing risk of slip-related falls among young adults with obesity.

    Science.gov (United States)

    Yang, Feng; Munoz, Jose; Han, Long-Zhu; Yang, Fei

    2017-05-24

    This study examined the effects of controlled whole-body vibration training on reducing risk of slip-related falls in people with obesity. Twenty-three young adults with obesity were randomly assigned into either the vibration or placebo group. The vibration and placebo groups respectively received 6-week vibration and placebo training on a side-alternating vibration platform. Before and after the training, the isometric knee extensors strength capacity was measured for the two groups. Both groups were also exposed to a standardized slip induced by a treadmill during gait prior to and following the training. Dynamic stability and fall incidences responding to the slip were also assessed. The results indicated that vibration training significantly increased the muscle strength and improved dynamic stability control at recovery touchdown after the slip occurrence. The improved dynamic stability could be resulted from the enhanced trunk segment movement control, which may be attributable to the strength increment caused by the vibration training. The decline of the fall rates from the pre-training slip to the post-training one was greater among the vibration group than the placebo group (45% vs. 25%). Vibration-based training could be a promising alternative or additional modality to active exercise-based fall prevention programs for people with obesity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Numerical modeling of time-dependent bio-convective stagnation flow of a nanofluid in slip regime

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    Full Text Available A numerical investigation of unsteady stagnation point flow of bioconvective nanofluid due to an exponential deforming surface is made in this research. The effects of Brownian diffusion, thermophoresis, slip velocity and thermal jump are incorporated in the nanofluid model. By utilizing similarity transformations, the highly nonlinear partial differential equations governing present nano-bioconvective boundary layer phenomenon are reduced into ordinary differential system. The resultant expressions are solved for numerical solution by employing a well-known implicit finite difference approach termed as Keller-box method (KBM. The influence of involved parameters (unsteadiness, bioconvection Schmidt number, velocity slip, thermal jump, thermophoresis, Schmidt number, Brownian motion, bioconvection Peclet number on the distributions of velocity, temperature, nanoparticle and motile microorganisms concentrations, the coefficient of local skin-friction, rate of heat transport, Sherwood number and local density motile microorganisms are exhibited through graphs and tables. Keywords: Unsteadiness, Bio-convection, Slip regime, Stagnation point flow, Numerical modeling

  3. Great earthquakes and slow slip events along the Sagami trough and outline of the Kanto Asperity Project

    Science.gov (United States)

    Kobayashi, R.; Yamamoto, Y.; Sato, T.; Shishikura, M.; Ito, H.; Shinohara, M.; Kawamura, K.; Shibazaki, B.

    2010-12-01

    The Kanto region is one of the most densely populated urban areas in the world. Complicated plate configurations are due to T-T-T type triple junction, island arc-island arc collision zone, and very shallow angle between axis of the Sagami trough and subducting direction. Great earthquakes along the Sagami trough have repeatedly occurred. The 1703 Genroku and 1923 (Taisho) Kanto earthquakes caused severe damages in the Tokyo metropolitan area. Intriguingly slow slip events have also repeatedly occurred in an area adjacent to the asperities of the great earthquakes, off Boso peninsula (e.g., Ozawa et al 2007). In the cases of the Nankai and Cascadia subduction zones, slow slip events occur at deeper levels than the asperity, in a transition zone between the asperity and a region of steady slip. In contrast, slow slip events in the Kanto region have occurred at relatively shallow depths, at the same level as the asperity, raising the possibility of friction controlled by different conditions to those (temperature and pressure) encountered at Nankai and Cascadia. We focus on three different types of seismic events occurring repeatedly at the almost same depth of the seismogenic zone along the Sagami trough (5-20 km) (1) The 1923 M~7.9 Taisho earthquake, located in Sagami Bay. Maximum slip is about 6 m, the recurrence interval is 200-400 yr, and the coupling rate is 80-100% (“coupling rates” = “slip amounts during earthquakes or slow-slip events” / [“rate of motion of the Philippine Sea Plate” - “recurrence interval”]) . (2) The 1703 M~8.2 Genroku earthquake, located in Sagami Bay, but also extending to the southern part of Boso Peninsula. Maximum slip is 15-20 m, the recurrence interval is ~2000 yr, and the coupling rate at the southern part of the Boso Peninsula is 10-30%. (3) Boso slow-slip events, located southeast of Boso Peninsula. Maximum slip is 15-20 cm over ~10 days, the recurrence interval is 5-6 yr, and the coupling rate is 70

  4. Two-Dimensional Stagnation-Point Velocity-Slip Flow and Heat Transfer over Porous Stretching Sheet

    Directory of Open Access Journals (Sweden)

    FEROZ AHMED SOOMRO

    2016-10-01

    Full Text Available Present paper investigates 2D (Two-Dimensional stagnation-point velocity-slip flow over porous stretching sheet. The governing non-linear PDEs (Partial Differential Equations are non-dimensionlized by using the similarity transformation technique that results into coupled non-linear ODEs (Ordinary Differential Equations. Such ODEs are then solved by using shooting technique with fourth-order Runge-Kutta method. Since the behavior of boundary layer stagnation-point flow depends on the rate of cooling and stretching. Therefore, the main objective of this paper is to analyze the effects of different working parameters on shear stress, heat transfer, velocity and temperature of fluid. The results revealed that the velocity-slip has significant effect on the fluid flow as well as on the heat transfer. The numerical results are also compared with existing work for no-slip condition and found to have good agreement with improved asymptotic behavior.

  5. Slipped capital femoral epiphysis: is it worth the risk and cost not to offer prophylactic fixation of the contralateral hip?

    Science.gov (United States)

    Clement, N D; Vats, A; Duckworth, A D; Gaston, M S; Murray, A W

    2015-10-01

    Controversy remains whether the contralateral hip should be fixed in patients presenting with unilateral slipped capital femoral epiphysis (SCFE). This retrospective study compares the outcomes and cost of those patients who had prophylactic fixation with those who did not. Between January 2000 and December 2010 a total of 50 patients underwent unilateral fixation and 36 had prophylactic fixation of the contralateral hip. There were 54 males and 32 females with a mean age of 12.3 years (9 to 16). The rate of a subsequent slip without prophylactic fixation was 46%. The risk of complications was greater, the generic health measures (Short Form-12 physical (p slip, and the diminished functional outcome associated with unilateral fixation. ©2015 The British Editorial Society of Bone & Joint Surgery.

  6. Laboratory study of electromagnetic initiation of slip

    Directory of Open Access Journals (Sweden)

    V. Chikhladze

    2002-06-01

    Full Text Available Recently Russian seismologists reported the triggering effect of MHD soundings on microseismic activity in the Central Asia test area.The paper focuses on an experimental test of the possibility of triggering the mechanical instability of a system that is close to critical state by a series of electromagnetic pulses.The mechanical system consisted of two pieces of rock;the upper piece can slip on the fixed supporting sample if the latter one is tilted up to the critical angle.In this state,the triggering of mechanical instability by some weak impact such as electrical pulse became more probable.The slope of support in the experiment is an analogue of tectonic stress in natural conditions.The preliminary experiments,carried out in a dry environment,at the humidity of atmosphere 30-50%,show that a strong EM-pulse induces sliding of a sample of rock (granite,basalt,labradoriteplaced on the supporting sample which is inclined at the slope close to,but less than,the critical angle with a probability 0.07.

  7. Analysis of bit-rock interaction during stick-slip vibrations using PDC cutting force model

    Energy Technology Data Exchange (ETDEWEB)

    Patil, P.A.; Teodoriu, C. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE

    2013-08-01

    Drillstring vibration is one of the limiting factors maximizing the drilling performance and also causes premature failure of drillstring components. Polycrystalline diamond compact (PDC) bit enhances the overall drilling performance giving the best rate of penetrations with less cost per foot but the PDC bits are more susceptible to the stick slip phenomena which results in high fluctuations of bit rotational speed. Based on the torsional drillstring model developed using Matlab/Simulink for analyzing the parametric influence on stick-slip vibrations due to drilling parameters and drillstring properties, the study of relations between weight on bit, torque on bit, bit speed, rate of penetration and friction coefficient have been analyzed. While drilling with the PDC bits, the bit-rock interaction has been characterized by cutting forces and the frictional forces. The torque on bit and the weight on bit have both the cutting component and the frictional component when resolved in horizontal and vertical direction. The paper considers that the bit is undergoing stick-slip vibrations while analyzing the bit-rock interaction of the PDC bit. The Matlab/Simulink bit-rock interaction model has been developed which gives the average cutting torque, T{sub c}, and friction torque, T{sub f}, values on cutters as well as corresponding average weight transferred by the cutting face, W{sub c}, and the wear flat face, W{sub f}, of the cutters value due to friction.

  8. An investigation of the effects of pneumatic actuator design on slip control for heavy vehicles

    Science.gov (United States)

    Miller, Jonathan I.; Cebon, David

    2013-01-01

    Progress in reducing actuator delays in pneumatic brake systems is opening the door for advanced anti-lock braking algorithms to be used on heavy goods vehicles. However, little has been published on slip controllers for air-braked heavy vehicles, or the effects of slow pneumatic actuation on their design and performance. This paper introduces a sliding mode slip controller for air-braked heavy vehicles. The effects of pneumatic actuator delays and flow rates on stopping performance and air (energy) consumption are presented through vehicle simulations. Finally, the simulations are validated with experiments using a hardware-in-the-loop rig. It is shown that for each wheel, pneumatic valves with delays smaller than 3 ms and orifice diameters around 8 mm provide the best performance.

  9. Phase slip and telegraph noise in δ-MoN nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Buh, Jože, E-mail: joze.buh@ijs.si [Jozef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana (Slovenia); Mrzel, Aleš; Kovič, Andrej; Kabanov, Viktor [Jozef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana (Slovenia); Jagličić, Zvonko [Institute of Mathematics, Physics and Mechanics, Jadranska 19, SI-1000 Ljubljana (Slovenia); University of Ljubljana, Faculty of Civil and Geodetic Engineering, Jamova 2, SI-1000 Ljubljana (Slovenia); Vrtnik, Stanislav; Koželj, Primož [Jozef Stefan Institute, Jozef Stefan Institute, Department of Condensed Matter Physics, Jamova 39, SI-1000 Ljubljana (Slovenia); Faculty of Mathematics and Physics, Jozef Stefan Institute, University of Ljubljana, SI-1000 Ljubljana (Slovenia); Mihailović, Dragan [Jozef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana (Slovenia); Faculty of Mathematics and Physics, Jozef Stefan Institute, University of Ljubljana, SI-1000 Ljubljana (Slovenia); Jozef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2017-04-15

    Highlights: • Normal to SC transition width is strongly dependent on the diameter of the wire. • Telegraph noise frequency can be controlled by bias current. • Bias current is controlling the stability of different resistive states. • Magnetic field blurs of transitions between resistive superconducting states. - Abstract: We have investigated the effect of the nanowire thickness on the superconducting resistive phase transition R(T) in δ-MoN nanowires. We have characterized the width of the transition in terms of thermally-activated phase-slip theory. A large increase in the width of the transition was found with the decrease of the nanowire thickness. Discrete phase-slip fluctuations also lead to the appearance of meta-stable resistive superconducting states in current-bearing superconducting wires, with spontaneous switching between them. We have investigated the effect of the bias current on the switching rate and the stability of different resistive states.

  10. Unstable fault slip induced by lawsonite dehydration in blueschist: Implication for the seismicity in the subducting oceanic crusts

    Science.gov (United States)

    Okazaki, K.; Hirth, G.

    2015-12-01

    Intermediate-depth earthquakes in cold subduction zones are observed within the subducting oceanic crust, as well as the subducting mantle In contrast, intermediate-depth earthquakes in hot subduction zones predominantly occur just below the Moho. These observations have stimulated interest in potential relationships between blueschist-facies metamorphism and seismicity, particularly through the dehydration reactions involving lawsonite. The rheology of these high-pressure and low-temperature metamorphic minerals is largely unknown. We conducted experiments on lawsonite accompanied by monitoring of acoustic emission (AE) in a Griggs-type deformation apparatus. Deformation was started at the confining pressure of 1.0 GPa, the temperature of 300 ˚C, and constant displacement rates of 0.16 to 0.016 μm/s, that correspond to equivalent strain rates (ɛ) of 9 × 10-5 to 9 × 10-6 1/s. In these experiments, temperature was increased at the temperature ramp rate of 0.5 to 0.05˚C/s above the thermal stability of lawsonite (600˚C) while the sample was deforming to test whether the dehydration reaction induces unstable fault slip. In contrast to similar tests on antigorite, unstable fault slip (i.e., stick-slip) occurred during dehydration reactions in the lawsonite gouge layer, and AE signals were continuously observed. Microstructural observations indicate that strain is highly localized along the fault (R1 and B shear), and the fault surface shows mirror-like slickensides. The unloading slope (i.e., rate of stress drop as a function of slip) during the unstable slip follows the stiffness of the apparatus at all experimental conditions regardless of the strain rate and temperature ramping rate. A thermal-mechanical scaling factor in the experiments covers the range estimated for natural subduction zones, indicating the potential for unstable frictional sliding within natural lawsonite layers to induce seismicity in cold subduction zones.

  11. Slipped capital femoral epiphysis: prevalence, pathogenesis, and natural history.

    Science.gov (United States)

    Novais, Eduardo N; Millis, Michael B

    2012-12-01

    Obesity is a risk factor for developing slipped capital femoral epiphysis (SCFE). The long-term outcome after SCFE treatment depends on the severity of residual hip deformity and the occurrence of complications, mainly avascular necrosis (AVN). Femoroacetabular impingement (FAI) is associated with SCFE-related deformity and dysfunction in both short and long term. We examined obesity prevention, early diagnosis, reducing AVN and hip deformity as strategies to reduce SCFE prevalence, and the long-term outcomes after treatment. A search of the literature using the PubMed database for the key concepts SCFE and treatment, natural history, obesity, and prevalence identified 218, 15, 26, and 49 abstracts, respectively. WHERE ARE WE NOW?: A correlation between rising childhood obesity and increasing incidence of SCFE has been recently reported. Residual abnormal morphology of the proximal femur is currently believed to be the mechanical cause of FAI and early articular cartilage damage in SCFE. WHERE DO WE NEED TO GO?: Reducing the increasing prevalence rate of SCFE is important. Treatment of SCFE should aim to reduce AVN rates and residual deformities that lead to FAI to improve the long-term functional and clinical outcomes. HOW DO WE GET THERE?: Implementing public health policies to reduce childhood obesity should allow for SCFE prevalence to drop. Clinical trials will evaluate whether restoring the femoral head-neck offset to avoid FAI along with SCFE fixation allows for cartilage damage prevention and lower rates of osteoarthritis. The recently described surgical hip dislocation approach is a promising technique that allows anatomic reduction with potential lower AVN rates in the treatment of SCFE.

  12. Stresses of PTT, Giesekus, and Oldroyd-B fluids in a Newtonian velocity field near the stick-slip singularity

    Science.gov (United States)

    Evans, J. D.; Palhares Junior, I. L.; Oishi, C. M.

    2017-12-01

    We characterise the stress singularity of the Oldroyd-B, Phan-Thien-Tanner (PTT), and Giesekus viscoelastic models in steady planar stick-slip flows. For both PTT and Giesekus models in the presence of a solvent viscosity, the asymptotics show that the velocity field is Newtonian dominated near to the singularity at the join of the stick and slip surfaces. Polymer stress boundary layers are present at both the stick and slip surfaces. By integrating along streamlines, we verify the polymer stress behavior of r-4/11 for PTT and r-5/16 for Giesekus, where r is the radial distance from the singularity. These asymptotic results for PTT and Giesekus do not hold in the limit of vanishing quadratic stress terms for Oldroyd-B. However, we can consider the Oldroyd-B model in the fixed kinematics of a prescribed Newtonian velocity field. In contrast to PTT and Giesekus, this is not the correct balance for the momentum equation but does allow insight into the behavior of the Oldroyd-B equations near the singularity. A three-region asymptotic structure is again apparent with now a polymer stress singularity of r-4/5. The high Weissenberg boundary layer equations are found to manifest themselves at the stick surface and are of thickness r3/2. At the slip surface, dominant balance between the upper convected stress and rate-of-strain terms gives a slip boundary layer of thickness r2. The solution of the slip boundary layer shows that the polymer stress is now singular along the slip surface. These results are supported through numerical integration along streamlines of the Oldroyd-B equations in a Newtonian velocity field. The Oldroyd-B model thus extends the point singularity at the join of the stick and slip surfaces to the whole of slip surface. As such, it does not have a physically meaningful solution in a Newtonian velocity field. We would expect a similar stress behavior for this model in the true viscoelastic velocity field.

  13. Experimental Characterization of a Flexible Thermal Slip Sensor

    Directory of Open Access Journals (Sweden)

    Eugenio Guglielmelli

    2012-11-01

    Full Text Available Tactile sensors are needed for effectively controlling the interaction between a robotic hand and the environment, e.g., during manipulation of objects, or for the tactile exploration of unstructured environments, especially when other sensing modalities, such as vision or audition, become ineffective. In the case of hand prostheses, mainly intended for dexterous manipulation of daily living objects, the possibility of quickly detecting slip occurrence, thus avoiding inadvertent falling of the objects, is prodromal to any manipulation task. In this paper we report on a slip sensor with no-moving parts, based on thermo-electrical phenomena, fabricated on a flexible substrate and suitable for integration on curved surfaces, such as robotic finger pads. Experiments performed using a custom made test bench, which is capable of generating controlled slip velocities, show that the sensor detects slip events in less than 50 ms. This response time is short enough for enabling future applications in the field of hand prosthetics.

  14. Revealing Slip Bands In A Metal-Matrix/Fiber Composite

    Science.gov (United States)

    Lerch, Bradley A.

    1995-01-01

    Experimental procedure includes heat treatments and metallographic techniques developed to facilitate studies of deformation of metal-matrix/fiber composite under stress. Reveals slip bands, indicative of plastic flow occurring in matrix during mechanical tests of specimens of composite.

  15. Experimental characterization of a flexible thermal slip sensor.

    Science.gov (United States)

    Francomano, Maria Teresa; Accoto, Dino; Guglielmelli, Eugenio

    2012-11-08

    Tactile sensors are needed for effectively controlling the interaction between a robotic hand and the environment, e.g., during manipulation of objects, or for the tactile exploration of unstructured environments, especially when other sensing modalities, such as vision or audition, become ineffective. In the case of hand prostheses, mainly intended for dexterous manipulation of daily living objects, the possibility of quickly detecting slip occurrence, thus avoiding inadvertent falling of the objects, is prodromal to any manipulation task. In this paper we report on a slip sensor with no-moving parts, based on thermo-electrical phenomena, fabricated on a flexible substrate and suitable for integration on curved surfaces, such as robotic finger pads. Experiments performed using a custom made test bench, which is capable of generating controlled slip velocities, show that the sensor detects slip events in less than 50 ms. This response time is short enough for enabling future applications in the field of hand prosthetics.

  16. Stick-slip and Torsional Friction Factors in Inclined Wellbores

    Directory of Open Access Journals (Sweden)

    Aarsnes Ulf Jakob F.

    2018-01-01

    The model is shown to have a good match with the surface and downhole behavior of two deviated wellbores for depths ranging from 1500 to 3000 meters. In particular, the model replicates the amplitude and period of the oscillations, in both the topside torque and the downhole RPM, as caused by the along-string stick slip. It is further shown that by using the surface behavior of the drill-string during rotational startup, an estimate of the static and dynamic friction factors along the wellbore can be obtained, even during stick-slip oscillations, if axial tension in the drillstring is considered. This presents a possible method to estimate friction factors in the field when off-bottom stick slip is encountered, and points in the direction of avoiding stick slip through the design of an appropriate torsional start-up procedure without the need of an explicit friction test.

  17. Quantifying effective slip length over micropatterned hydrophobic surfaces

    NARCIS (Netherlands)

    Tsai, Peichun Amy; Peters, A.M.; Pirat, C.; Wessling, Matthias; Lammertink, Rob G.H.; Lohse, Detlef

    2009-01-01

    We employ microparticle image velocimetry to investigate laminar microflows in hydrophobic microstructured channels, in particular the slip length. These microchannels consist of longitudinal microgrooves, which can trap air and prompt a shear-free boundary condition and thus slippage enhancement.

  18. Continued growth after fixation of slipped capital femoral epiphysis

    National Research Council Canada - National Science Library

    Holmdahl, Per; Backteman, Torsten; Danielsson, Aina; Kärrholm, Johan; Riad, Jacques

    2016-01-01

    When treating slipped capital femoral epiphysis (SCFE), a smooth pin with a hook or a short threaded screw can be used to allow further growth, which could be important to prevent the development of impingement and early arthritis...

  19. Controversies in management of slipped capital femoral epiphysis

    National Research Council Canada - National Science Library

    Johari, Ashok N; Pandey, Ritesh A

    2016-01-01

    .... This being a recent development, it lacks the support of long term follow up and it remains to be seen if this is a better alternative of managing displaced and unstable slipped capital femoral epiphysis...

  20. Case report: bilateral slipped capital femoral epiphyses and hormone replacement.

    Science.gov (United States)

    Nourbakhsh, Ali; Ahmed, Hasan A; McAuliffe, Thomas B; Garges, Kim J

    2008-03-01

    A 24-year-old woman presented with an 11-year history of bilateral hip pain. Radiographs of the hips revealed severe bilateral slipped upper femoral epiphyses; the left side was more severely slipped than the right. While moving the hips under fluoroscopy we observed motion at the physes and reproduced the patient's pain; the motion confirmed the diagnosis of chronic slipped capital femoral epiphysis. Endocrinology tests showed hypothyroidism. After 1 year of thyroxin therapy, the patient's pain subsided and radiographs of the hips showed fusion of the physes. This case emphasizes the importance of screening for an endocrine disorder in patients with slipped capital femoral epiphysis particularly in adults and shows fusion can occur once the underlying endocrine abnormality is treated.

  1. [Study on the compatibility of slip casting aluminous ceramic crowns

    Science.gov (United States)

    Wan, Q B; Xue, M; You, L; Du, C S; Chao, Y L

    1997-03-01

    One of the key factors for a good slip casting aluminous ceramic crown is good compatibility between its core material and the veneering porcelain.The chemical and thermal compatibility of two slip casting aluminous ceramic crown systems(In-Ceram and GI-I) were investigated by means of SEM and EDAX,thermal shock tests were also performed to evaluate the crazing resistance.The results showed: the crazing resistance of In-Ceram was 158 degrees centigrade,and that of GI-I was degrees centigrade;there existed tightly bonded interfaces between the slip casting aluminous ceramic cores and the veneering porcelains in both of the two systems,where ion transferences were found.The results also suggested good compatibility of the two slip casting aluminous ceramic crown systems.

  2. High-level Petri Nets

    DEFF Research Database (Denmark)

    High-level Petri nets are now widely used in both theoretical analysis and practical modelling of concurrent systems. The main reason for the success of this class of net models is that they make it possible to obtain much more succinct and manageable descriptions than can be obtained by means...... of low-level Petri nets - while, on the other hand, they still offer a wide range of analysis methods and tools. The step from low-level nets to high-level nets can be compared to the step from assembly languages to modern programming languages with an elaborated type concept. In low-level nets...... there is only one kind of token and this means that the state of a place is described by an integer (and in many cases even by a boolean). In high-level nets each token can carry a complex information/data - which, e.g., may describe the entire state of a process or a data base. Today most practical...

  3. Beyond Brittle Deformation: Insights into Seismogenic Slip Processes from Natural and Experimental Faults

    Science.gov (United States)

    Holdsworth, R.; De Paola, N.; Bullock, R. J.; Collettini, C.; Viti, C.; Nielsen, S. B.

    2015-12-01

    Shear displacements in upper crustal faults are typically localized within cm- to m-thick high strain fault cores composed of interlayered tabular domains of cataclasite and gouge. Evidence from exhumed/exposed seismic faults shows that the great majority of co-seismic slip is taken up along narrow (frictional heating that potentially promotes thermally-activated dynamic weakening mechanisms. We can recreate these processes in the laboratory using displacement-controlled friction experiments performed in a rotary shear apparatus on fault gouges of known composition deformed at seismic slip rates (v > 1ms-1) and normal stresses of up to 20 MPa. A sequential sampling approach is used in which slip is arrested at different stages of the observed friction evolution (e.g. post-compaction, peak friction, steady state after weakening). This allows the evolution of gouge microstructures and deformation mechanisms in the experimental samples to be: a) related to the evolving temperature regimes in the PSZ and changing mechanical behavior; and b) compared to natural PSZ/PSSs. Using this approach we have investigated the behavior and deformation mechanisms of gouges made of common, rock-forming minerals (calcite, clays, olivine, quartz) both in pure form and, in some cases, as mixed compositions deformed under a range of experimental conditions. We have studied the effects of varying confining pressure, fluid content (room humidity vs water saturated) and composition (de-ionized water vs brine) and slip rate (e.g. seismic vs. sub-seismic). Our findings - and those of others - reveal a startling diversity of 'non-brittle' micro- to nano-scale deformation processes (e.g. viscous GBS, particulate flow). This has implications for our understanding of the frictional strength of faults, the recognition of past seismogenic events in natural examples and the forecasting of future earthquakes.

  4. Modeling slow-slip segmentation in Cascadia subduction zone constrained by tremor locations and gravity anomalies

    Science.gov (United States)

    Li, Duo; Liu, Yajing

    2017-04-01

    Along-strike segmentation of slow-slip events (SSEs) and nonvolcanic tremors in Cascadia may reflect heterogeneities of the subducting slab or overlying continental lithosphere. However, the nature behind this segmentation is not fully understood. We develop a 3-D model for episodic SSEs in northern and central Cascadia, incorporating both seismological and gravitational observations to constrain the heterogeneities in the megathrust fault properties. The 6 year automatically detected tremors are used to constrain the rate-state friction parameters. The effective normal stress at SSE depths is constrained by along-margin free-air and Bouguer gravity anomalies. The along-strike variation in the long-term plate convergence rate is also taken into consideration. Simulation results show five segments of ˜Mw6.0 SSEs spontaneously appear along the strike, correlated to the distribution of tremor epicenters. Modeled SSE recurrence intervals are equally comparable to GPS observations using both types of gravity anomaly constraints. However, the model constrained by free-air anomaly does a better job in reproducing the cumulative slip as well as more consistent surface displacements with GPS observations. The modeled along-strike segmentation represents the averaged slip release over many SSE cycles, rather than permanent barriers. Individual slow-slip events can still propagate across the boundaries, which may cause interactions between adjacent SSEs, as observed in time-dependent GPS inversions. In addition, the moment-duration scaling is sensitive to the selection of velocity criteria for determining when SSEs occur. Hence, the detection ability of the current GPS network should be considered in the interpretation of slow earthquake source parameter scaling relations.

  5. Phase slip fluctuations in low-dimensional superconductors: A numerical study using the string method

    Science.gov (United States)

    Qiu, Chunyin

    In the thesis, we numerically study the phase slip fluctuations in low-dimensional superconducting systems using the string method. The string method has been presented as an efficient numerical tool for the study of thermally activated rare events. This numerical approach locates the minimal energy path (MEP) which is the most probable transition pathway connecting two metastable/stable states in configuration space. From the MEP the saddle point is determined and the corresponding energy barrier is also obtained. We first study the phase slips in one-dimensional superconducting wires with nonuniform cross section. The free-energy barrier and the pre-exponential factor associated with the transition rate (resistance) are numerically calculated. We find that even a weak defect can greatly enhance the total rate of transition. Then we study the phase slips in two-dimensional superconducting strips and ultrathin hollow superconducting cylinders. In these two systems, the phase slips may occur via free-energy saddle points of two distinct kinds. The saddle points of the first kind exhibit a one-dimensional order parameter variation described by the Langer-Ambegaokar-McCumber-Halperin theory [Phys. Rev 164, 498 (1967); Phys. Rev B 1, 1054 (1970)]. The saddle points of the second kind exhibit a two-dimensional variation of order parameter with vortex/antivotex involved. Finally, we extend the string method to investigate the critical nuclei for capillary condensation in a slit pore. The application shows the great power of string method in evaluating the critical nuclei in various liquid-vapor phase transitions.

  6. The slow slip event in the Tokai region, central Japan, since 2013 as seen from GPS data

    Science.gov (United States)

    Sakaue, H.; Fukuda, J.; Kato, T.; Nishimura, T.

    2016-12-01

    In the Tokai region, cetral Japan, the previous long-term slow slip event (SSE) occurred on the subducting Philippine Sea plate from 2000 to 2005, the longest SSE ever found. In addition, many short-term SSEs have been observed in the Tokai region since 2004. Ozawa et al. (2016) reported that a slow slip event seems to have started in the similar area of the previous Tokai long term SSE in the beginning of 2013. We analyzed GPS data in the Tokai region to estimate the temporal evolution of the current event. GPS data from 1 Jan. 2008 to 30 Apr. 2015 were used in this study. The GIPSY-OASIS II software was used to estimate daily coordinates of 226 GPS stations from the GEONET in the Tokai district. The 2011 Tohoku-oki earthquake (Mw9.0) occurred on 11 Mar. 2011 and post-seismic deformation has also been observed in the Tokai region since then. Therefore, the effects of the post-seismic deformation due to the Tohoku-oki earthquake were removed by fitting the data from 11 Mar. 2011 to 31 Dec. 2012 with simple mathematical functions. We approximate the post-seismic deformations by the sum of exponential and logarithmic functions and subtract the estimated post-seismic deformation from the GPS time series. After removing this compornent, we applied a time-dependent inversion method to the data to obtain the spatio-temporal evolution of slip on the Philippine Sea plate beneath the Tokai region. For this purpose, we used a modified Network Inversion Filter (NIF) (Fukuda et al., 2008). The original NIF (Segall and Matthews, 1997) assumes a constant hyperparameter for the temporal smoothing of slip rate and thus results in oversmoothing of slip rate. The modified NIF assumes a time variable hyperparameter, so that changes in slip rate are effectively extracted from GPS time series. The results indicate that maximum slip for the long-term SSE from 1 Jan. 2013 to 30 Apr. 2015 was estimated to be about 6 cm and the large slip was located in nearly the same area as or slightly

  7. Characterization of Natural Slip Surfaces Relevant to Earthquake Mechanics

    Science.gov (United States)

    Chester, J. S.; Kronenberg, A. K.; Chester, F. M.; Guillemette, R. N.

    2003-12-01

    The Punchbowl fault, an ancient trace of the San Andreas, displays extreme localization of displacement to a meters-thick fault core containing an ultracataclasite layer with mesoscale slip surfaces. New maps of the Punchbowl fault slip surface and ultracataclasite produced using optical and electron microscopy document that extreme localization of slip also occurred at the microscopic scale. The prominent mesoscopic scale slip surface is a thin (mm thick), texturally distinct layer of ultracataclasite with a crystal-lattice preferred orientation, as evidenced by uniform birefringence, within which distinct microscopic slip surfaces are evident. Thin sinuous seams and possible injection-like structures of opaque, ultrafine material and thin zones of cataclastic flow occur at the microscopic slip surface. Evidence for multiple episodes of synfaulting mineral alteration and cementation in the surrounding ultracataclasite documents chemical processes likely were important to strength recovery. Overall, microstructural features are consistent with the inference that repeated slip occurred on the mesoscopic-scale slip surface, and that older slip-surfaces are present throughout the ultracataclasite layer. Diffraction-contrast TEM imaging, micro-electron diffraction, quantitative elemental mapping and energy dispersive spectroscopy (EDS) are being used to determine relative abundance and types of crystalline phases, glass, or other friction-induced amorphous phases (e.g., silica gel). Preliminary TEM observations indicate that the ultracataclasite consists almost entirely of ultrafine particles (4 to 400 nm diameter), with rounded relict grains of the host rocks, faulted and unfaulted veins, sheared and kinked clay minerals, and new, euhedral grains. Low permeabilities are implied by the fine grain size and corresponding nm-scale pores. Although rapid slip on mesoscopic scale slip surfaces would be expected to have produced thermal transients, we have not, as yet, found

  8. Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study

    Directory of Open Access Journals (Sweden)

    Irish SR

    2008-06-01

    Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.

  9. Modelling Paleoearthquake Slip Distributions using a Gentic Algorithm

    Science.gov (United States)

    Lindsay, Anthony; Simão, Nuno; McCloskey, John; Nalbant, Suleyman; Murphy, Shane; Bhloscaidh, Mairead Nic

    2013-04-01

    Along the Sunda trench, the annual growth rings of coral microatolls store long term records of tectonic deformation. Spread over large areas of an active megathrust fault, they offer the possibility of high resolution reconstructions of slip for a number of paleo-earthquakes. These data are complex with spatial and temporal variations in uncertainty. Rather than assuming that any one model will uniquely fit the data, Monte Carlo Slip Estimation (MCSE) modelling produces a catalogue of possible models for each event. From each earthquake's catalogue, a model is selected and a possible history of slip along the fault reconstructed. By generating multiple histories, then finding the average slip during each earthquake, a probabilistic history of slip along the fault can be generated and areas that may have a large slip deficit identified. However, the MCSE technique requires the production of many hundreds of billions of models to yield the few models that fit the observed coral data. In an attempt to accelerate this process, we have designed a Genetic Algorithm (GA). The GA uses evolutionary operators to recombine the information held by a population of possible slip models to produce a set of new models, based on how well they reproduce a set of coral deformation data. Repeated iterations of the algorithm produce populations of improved models, each generation better satisfying the coral data. Preliminary results have shown the GA to be capable of recovering synthetically generated slip distributions based their displacements of sets of corals faster than the MCSE technique. The results of the systematic testing of the GA technique and its performance using both synthetic and observed coral displacement data will be presented.

  10. Stick-slip patterns in a model frictional interface

    Science.gov (United States)

    Tsekenis, Georgios; Tatar, Demet; Rubinstein, Shmuel; Weitz, David; Aziz, Michael; Spaepen, Frans

    2015-03-01

    We present measurements of the local displacements during slip-stick motion of two rough surfaces sliding over one another. The surfaces are cast in polymer and have roughness on the order of 30 μm . The displacements are observed by confocal microscopy of embedded fluorescent particles, and measured by PIV. The displacement patterns during large and small slip events are directly observed and analyzed by statistical methods.

  11. Pro asynchronous programming with .NET

    CERN Document Server

    Blewett, Richard; Ltd, Rock Solid Knowledge

    2014-01-01

    Pro Asynchronous Programming with .NET teaches the essential skill of asynchronous programming in .NET. It answers critical questions in .NET application development, such as: how do I keep my program responding at all times to keep my users happy how do I make the most of the available hardware how can I improve performanceIn the modern world, users expect more and more from their applications and devices, and multi-core hardware has the potential to provide it. But it takes carefully crafted code to turn that potential into responsive, scalable applications.With Pro Asynchronous Programming

  12. Conformal Nets II: Conformal Blocks

    Science.gov (United States)

    Bartels, Arthur; Douglas, Christopher L.; Henriques, André

    2017-08-01

    Conformal nets provide a mathematical formalism for conformal field theory. Associated to a conformal net with finite index, we give a construction of the `bundle of conformal blocks', a representation of the mapping class groupoid of closed topological surfaces into the category of finite-dimensional projective Hilbert spaces. We also construct infinite-dimensional spaces of conformal blocks for topological surfaces with smooth boundary. We prove that the conformal blocks satisfy a factorization formula for gluing surfaces along circles, and an analogous formula for gluing surfaces along intervals. We use this interval factorization property to give a new proof of the modularity of the category of representations of a conformal net.

  13. Nucleation of dynamic slip on a hydraulically fractured fault

    Science.gov (United States)

    Azad, M.; Garagash, D. I.; Satish, M.

    2017-04-01

    This work is concerned with the relationship between hydraulic fracturing injection into a fault and the possibility of a seismic slip. The results of this study show that the nucleation of dynamic slip on a fault with slip-weakening friction is only weakly dependent on the magnitude of the stress perturbation ahead of the propagating hydraulic fracture (HF), or the HF propagation regime, and is mainly controlled by the hydraulic fracture length (i.e., the size of the fully unloaded fault segment at a given time). The growth of the fault slipping patch remains stable when the background shear stress τ0 is smaller than the residual fault strength τr under ambient conditions. Otherwise (τ0>τr), nucleation of dynamic slip takes place when the hydraulic fracture grows to the critical size ℓc, which is vanishingly small ∝τp-τ0 for critically stressed faults (i.e., when the background stress approaches the fault peak strength, τ0→τp) and is diverging as ∝1/(τ0-τr) when the stability boundary is approached (τ0→τr). Our solution for the critical HF size allows to infer the corresponding fluid injection volume that may lead to slip instability on a fault with given frictional properties and background stress.

  14. Triggering the mechanical (slip) instability in laboratory experimental model

    Science.gov (United States)

    Devidze, M.; Chelidze, T.; Varamashvili, N.

    2008-05-01

    Recent laboratory experiments testify possibility of significant influence of elastic and electromagnetic (EM) fields to affect (hamper or initiate) slip. This work focuses on experimental test of possibility of triggering the mechanical instability of system, which is close to the critical state, by electromagnetic pulses. The mechanical system consisted of two pieces of rock (basalt).This system is driven close to the critical state, namely by placing the rock plate on the inclined supporting sample at the slope angle less than, but close to the critical slip angle. In this state the triggering of mechanical instability by some weak impact such as electrical pulse became more probable. It has been found that when the EM field is nearly parallel to the slip plane the EM impact initiates the slip with the probability at the voltage and with the probability at . On the other hand, if the EM field is normal to the slip surface, application of EM pulse hampers the slip. The slope of support in experiment is analogue of tectonic stress in natural conditions. We conclude that our laboratory experiments give a sound principal basis for the interpretation of the field data on the control of seismic regime by relatively weak natural or artificial perturbations; of course, in the earth crust the detailed physical mechanisms of coupling between tectonic forces and superimposed perturbations may be different.

  15. Valgus slipped capital femoral epiphysis: subcapital growth plate orientation analysis.

    Science.gov (United States)

    Koczewski, Paweł

    2013-11-01

    The aim of the study was to determine the risk factors of unusual, lateral direction of epiphyseal displacement in primarily unilateral slipped capital femoral epiphysis (SCFE) patients with a special focus on radiological parameters of an unaffected hip. A total of 115 patients (75 boys, 40 girls), mean age 13.2 years (8.4-18.6), were analyzed. The mean follow-up time was 11 years (2-29). The proportion of valgus slip among SCFE patients was 11 of 115 cases (9.6%). The patients with valgus slip compared with the classic ones were predominantly females (55 vs. 33%), were younger (11.1 vs. 13.4 years), had a greater epiphyseal-shaft angle (67.4 vs. 59.1°), smaller displacement in the frontal plane (absolute value 6.7 vs. 15°), and a lower risk of contralateral slip (27 vs. 65%). There was no difference in the neck-shaft angle and epiphyseal-neck angle value. A more horizontal orientation of the subcapital growth plate, assessed by epiphyseal-shaft angle, can be considered a conducive factor in the valgus direction of epiphyseal slip in SCFE. In valgus SCFE cases, there is a smaller degree of epiphyseal displacement in both the sagittal and the coronal plane and a lower risk of consecutive contralateral slip.

  16. Intracapsular Pressures After Stable Slipped Capital Femoral Epiphysis.

    Science.gov (United States)

    Crepeau, Allison; Birnbaum, Mark; Vander Have, Kelly; Herrera-Soto, Jose

    2015-12-01

    Stable slipped capital femoral epiphysis (SCFE) has been shown to have a lower rate of avascular necrosis than unstable SCFE. A recent study found increased intracapsular hip pressures in the setting of unstable SCFE, thus increasing the risk of osteonecrosis. The purpose of this study was to measure the intracapsular pressure in stable SCFE and compare it to the intracapsular pressure in normal hips and in unstable SCFE. Thirteen hips with stable SCFE and 15 hips with unstable SCFE were identified. Using a side-bored needle, intracapsular hip pressures were measured at the time of surgery. Within these 2 study groups, 11 unaffected (normal) hips were also measured. Diastolic blood pressure and mean arterial pressure at the time of measurement were also recorded. The average intracapsular hip pressure in the stable SCFE group was 27.0 mm Hg, whereas the average pressure in the unstable SCFE group was 48.2 mm Hg and the average pressure in the normal group was 21.8 mm Hg. There was no significant difference between the normal and stable SCFE groups. There was a statistically significant difference between the stable SCFE and unstable SCFE groups (Pslips to decrease the elevated hip pressure but not in stable SCFE.

  17. Nocturia Is Associated with Slipping and Falling.

    Directory of Open Access Journals (Sweden)

    So Young Kim

    Full Text Available Several reports have demonstrated associations between falls and nocturia in the elderly. However, little information is available regarding other age groups. This study evaluated the relationship between the frequency of nocturia and falls in men using a large, population-based survey in Korea, and the results were adjusted for various confounding factors. Data from a 2011 Korean community health survey (KCHS were retrieved for 92,660 men aged 19 to 103 years. Information regarding the history of slips or falls in the past year was collected. The frequency of nocturia was classified as 0, 1, 2, 3, 4, and ≥ 5 instances a night. Walking during the day, education, income, body mass index (BMI, smoking, alcohol consumption, sleep time, stress level and medical histories of hypertension, diabetes mellitus, hyperlipidemia, cerebral stroke, angina or myocardial infarction, arthritis, and osteoporosis were adjusted using multiple logistic regression analysis with complex sampling. A subgroup analysis was conducted for young (19-30 years, middle-aged (31-60 years, and elderly individuals (61+ years. Approximately 14.6% of the men had a history of falls. Their mean age was 42.9 years, which was significantly higher than that of the non-faller group (P < 0.001. An increased frequency of nocturia was associated with increased adjusted odds ratio (AOR for falls (AOR for 1 instance of nocturia/night = 1.41 [95% confidence interval, 1.33-1.50]; AOR for 2 instances = 1.41 [1.33-1.50]; AOR for 3 instances = 2.00 [1.75-2.28]; AOR for 4 instances = 2.12 [1.73-2.61]; AOR for ≥ 5 instances = 2.02 [1.74-2.36], P < 0.001. In the subgroup analysis, the AORs for falls significantly increased in all age groups as the frequency of nocturia increased.

  18. A Multicoefficient Slip-Corrected Reynolds Equation for Micro-Thin Film Gas Lubrication

    Directory of Open Access Journals (Sweden)

    Ng Eddie Yin-Kwee

    2005-01-01

    Full Text Available This work investigates and analyzes the performance of conventional slip models among various regimes of Knudsen number and developes a new multicoefficient slip-velocity model, by using Taguchi quality control techniques and numerical analysis. A modified Reynolds equation is also derived based on the new slip-flow model. The multicoefficient slip model and its slip-corrected Reynolds equation are suitable to a wide Knudsen range from slip to transition regime. In comparison with other conventional slip models, it is found that the current results have a better agreement with the solution obtained from the linearized Boltzmann equation and direct simulation of Monte Carlo method (DSMC.

  19. Petri Net Tool Overview 1986

    DEFF Research Database (Denmark)

    Jensen, Kurt; Feldbrugge, Frits

    1987-01-01

    This paper provides an overview of the characteristics of all currently available net based tools. It is a compilation of information provided by tool authors or contact persons. A concise one page overview is provided as well....

  20. Understanding Net Zero Energy Buildings

    DEFF Research Database (Denmark)

    Salom, Jaume; Widén, Joakim; Candanedo, José

    2011-01-01

    Although several alternative definitions exist, a Net-Zero Energy Building (Net ZEB) can be succinctly described as a grid-connected building that generates as much energy as it uses over a year. The “net-zero” balance is attained by applying energy conservation and efficiency measures...... and by incorporating renewable energy systems. While based on annual balances, a complete description of a Net ZEB requires examining the system at smaller time-scales. This assessment should address: (a) the relationship between power generation and building loads and (b) the resulting interaction with the power grid....... This paper presents and categorizes quantitative indicators suitable to describe both aspects of the building’s performance. These indicators, named LMGI - Load Matching and Grid Interaction indicators, are easily quantifiable and could complement the output variables of existing building simulation tools...

  1. PolicyNet Publication System

    Data.gov (United States)

    Social Security Administration — The PolicyNet Publication System project will merge the Oracle-based Policy Repository (POMS) and the SQL-Server CAMP system (MSOM) into a new system with an Oracle...

  2. KM3NeT

    CERN Multimedia

    KM3NeT is a large scale next-generation neutrino telescope located in the deep waters of the Mediterranean Sea, optimized for the discovery of galactic neutrino sources emitting in the TeV energy region.

  3. Net Neutrality: Background and Issues

    National Research Council Canada - National Science Library

    Gilroy, Angele A

    2006-01-01

    .... The move to place restrictions on the owners of the networks that compose and provide access to the Internet, to ensure equal access and nondiscriminatory treatment, is referred to as "net neutrality...

  4. Petri Nets in Cryptographic Protocols

    DEFF Research Database (Denmark)

    Crazzolara, Federico; Winskel, Glynn

    2001-01-01

    A process language for security protocols is presented together with a semantics in terms of sets of events. The denotation of process is a set of events, and as each event specifies a set of pre and postconditions, this denotation can be viewed as a Petri net. By means of an example we illustrate...... how the Petri-net semantics can be used to prove security properties....

  5. The Economics of Net Neutrality

    OpenAIRE

    Hahn, Robert W.; Wallsten, Scott

    2006-01-01

    This essay examines the economics of "net neutrality" and broadband Internet access. We argue that mandating net neutrality would be likely to reduce economic welfare. Instead, the government should focus on creating competition in the broadband market by liberalizing more spectrum and reducing entry barriers created by certain local regulations. In cases where a broadband provider can exercise market power the government should use its antitrust enforcement authority to police anticompetitiv...

  6. Simulation and modelling of slip flow over surfaces grafted with polymer brushes and glycocalyx fibres.

    Science.gov (United States)

    Deng, Mingge; Li, Xuejin; Liang, Haojun; Caswell, Bruce; Karniadakis, George Em

    2012-11-01

    Fabrication of functionalized surfaces using polymer brushes is a relatively simple process and parallels the presence of glycocalyx filaments coating the luminal surface of our vasculature. In this paper, we perform atomistic-like simulations based on dissipative particle dynamics (DPD) to study both polymer brushes and glycocalyx filaments subject to shear flow, and we apply mean-field theory to extract useful scaling arguments on their response. For polymer brushes, a weak shear flow has no effect on the brush density profile or its height, while the slip length is independent of the shear rate and is of the order of the brush mesh size as a result of screening by hydrodynamic interactions. However, for strong shear flow, the polymer brush is penetrated deeper and is deformed, with a corresponding decrease of the brush height and an increase of the slip length. The transition from the weak to the strong shear regime can be described by a simple 'blob' argument, leading to the scaling γ̇0 ∝ σ3/2, where γ̇0 is the critical transition shear rate and σ is the grafting density. Furthermore, in the strong shear regime, we observe a cyclic dynamic motion of individual polymers, causing a reversal in the direction of surface flow. To study the glycocalyx layer, we first assume a homogeneous flow that ignores the discrete effects of blood cells, and we simulate microchannel flows at different flow rates. Surprisingly, we find that, at low Reynolds number, the slip length decreases with the mean flow velocity, unlike the behaviour of polymer brushes, for which the slip length remains constant under similar conditions. (The slip length and brush height are measured with respect to polymer mesh size and polymer contour length, respectively.) We also performed additional DPD simulations of blood flow in a tube with walls having a glycocalyx layer and with the deformable red blood cells modelled accurately at the spectrin level. In this case, a plasma cell-free layer

  7. Effects of perturbation-based slip training using a virtual reality environment on slip-induced falls.

    Science.gov (United States)

    Parijat, Prakriti; Lockhart, Thurmon E; Liu, Jian

    2015-04-01

    The purpose of the current study was to design and evaluate the effectiveness of virtual reality training in improving recovery reactions and reducing fall frequency in older adults. Twenty-four older adults were recruited and randomly assigned to two groups (virtual reality training and control). Both groups underwent three sessions including baseline slip, training and transfer of training on slippery surface. Both groups experienced two slips, one during baseline and the other during the transfer of training trial. The training group underwent 12 simulated slips using a visual perturbation induced by tilting a virtual reality scene while walking on the treadmill and the control group performed normal walking during the training session. Kinematic and kinetic data were collected during all the sessions. Results demonstrated a reduced incidence of falls in the training group during the transfer of training trial as compared to the control group. The training group was able to transfer reactive control strategies learned during training to the second slip trial. The reactive adjustments included reduced slip distance. Additionally, gait parameters reflective of gait instability (stride length, step width, variability in stride velocity) reduced after walking in the VR environment for 15-20 min. The results indicated a beneficial effect of the virtual reality training in reducing slip severity and recovery kinematics in healthy older adults.

  8. Stick-slip water penetration into capillaries coated with swelling hydrogel.

    Science.gov (United States)

    Silva, J E; Geryak, R; Loney, D A; Kottke, P A; Naik, R R; Tsukruk, V V; Fedorov, A G

    2015-08-07

    We have observed intriguing stick-slip behavior during capillary pressure driven filling of borosilicate microtubes coated with hydrogel on their inner wall. Swelling of hydrogel upon exposure to a translating waterfront is accompanied by "stick-and-slip" motion. This results in the macroscopic filling velocity for water penetration into glass capillaries coated with poly(N-isopropylacrylamide) (PNIPAM) being constant throughout the filling process, and reduced by three orders of magnitude when compared to filling of uncoated capillaries. A simple scaling analysis is used to introduce a possible explanation by considering the mechanisms responsible for pinning and unpinning of the contact line. The explanation assumes that the time scale for water diffusion into a hydrogel film and the resulting swelling/change of the local meniscus contact angle define the duration of each "stick" event. The "slip" length scale is in turn established by the elastocapillary deformation of dry hydrogel at the pinning point of the contact line. The sequential dynamics of these processes then determine the rate of water filling into a swelling capillary. Collectively, these experimental and theoretical results provide a new conceptual framework for liquid motion confined by soft, dynamically evolving polymer interfaces, in which the system creates an energy barrier to further motion through elasto-capillary deformation, and then lowers the barrier through diffusive softening. This insight has implications for optimal design of microfluidic and lab-on-a-chip devices based on stimuli-responsive smart polymers.

  9. The 2012 Brawley swarm triggered by injection-induced aseismic slip

    Science.gov (United States)

    Wei, Shengji; Avouac, Jean-Philippe; Hudnut, Kenneth W.; Donnellan, Andrea; Parker, Jay W.; Graves, Robert W.; Helmberger, Don; Fielding, Eric; Liu, Zhen; Cappa, Frederic; Eneva, Mariana

    2015-07-01

    It has long been known that fluid injection or withdrawal can induce earthquakes, but the underlying mechanisms remain elusive. For example, the 2012 Brawley swarm, which produced two strike-slip shocks with magnitudes larger than 5.3 and surface ruptures in the close vicinity of a geothermal field, started with earthquakes about 5 km deeper than the injection depth (∼1.5 km). This makes the causality between the injection and seismicity unclear. Here, we jointly analyze broadband and strong motion waveforms, UAVSAR, leveling measurements and field observations to reveal the detailed seismic and aseismic faulting behaviors associated with the 2012 Brawley swarm. In particular, path calibration established from smaller events in the swarm allows waveform inversion to be conducted up to 3 Hz to resolve finite rupture process of the Mw 4.7 normal event. Our results show that the 2012 earthquake sequence was preceded by aseismic slip on a shallow normal fault beneath the geothermal field. Aseismic slip initiated in 2010 when injection rate rapidly increased and triggered the following earthquakes subsequently, including unusually shallow and relatively high frequency seismic excitations on the normal fault. In this example, seismicity is induced indirectly by fluid injection, a result of mediation by aseismic creep, rather than directly by a pore pressure increase at the location of the earthquakes.

  10. Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal.

    Science.gov (United States)

    Galetzka, J; Melgar, D; Genrich, J F; Geng, J; Owen, S; Lindsey, E O; Xu, X; Bock, Y; Avouac, J-P; Adhikari, L B; Upreti, B N; Pratt-Sitaula, B; Bhattarai, T N; Sitaula, B P; Moore, A; Hudnut, K W; Szeliga, W; Normandeau, J; Fend, M; Flouzat, M; Bollinger, L; Shrestha, P; Koirala, B; Gautam, U; Bhatterai, M; Gupta, R; Kandel, T; Timsina, C; Sapkota, S N; Rajaure, S; Maharjan, N

    2015-09-04

    Detailed geodetic imaging of earthquake ruptures enhances our understanding of earthquake physics and associated ground shaking. The 25 April 2015 moment magnitude 7.8 earthquake in Gorkha, Nepal was the first large continental megathrust rupture to have occurred beneath a high-rate (5-hertz) Global Positioning System (GPS) network. We used GPS and interferometric synthetic aperture radar data to model the earthquake rupture as a slip pulse ~20 kilometers in width, ~6 seconds in duration, and with a peak sliding velocity of 1.1 meters per second, which propagated toward the Kathmandu basin at ~3.3 kilometers per second over ~140 kilometers. The smooth slip onset, indicating a large (~5-meter) slip-weakening distance, caused moderate ground shaking at high frequencies (>1 hertz; peak ground acceleration, ~16% of Earth's gravity) and minimized damage to vernacular dwellings. Whole-basin resonance at a period of 4 to 5 seconds caused the collapse of tall structures, including cultural artifacts. Copyright © 2015, American Association for the Advancement of Science.

  11. A geophone wireless sensor network for investigating glacier stick-slip motion

    Science.gov (United States)

    Martinez, Kirk; Hart, Jane K.; Basford, Philip J.; Bragg, Graeme M.; Ward, Tyler; Young, David S.

    2017-08-01

    We have developed an innovative passive borehole geophone system, as part of a wireless environmental sensor network to investigate glacier stick-slip motion. The new geophone nodes use an ARM Cortex-M3 processor with a low power design capable of running on battery power while embedded in the ice. Only data from seismic events was stored, held temporarily on a micro-SD card until they were retrieved by systems on the glacier surface which are connected to the internet. The sampling rates, detection and filtering levels were determined from a field trial using a standard commercial passive seismic system. The new system was installed on the Skalafellsjökull glacier in Iceland and provided encouraging results. The results showed that there was a relationship between surface melt water production and seismic event (ice quakes), and these occurred on a pattern related to the glacier surface melt-water controlled velocity changes (stick-slip motion). Three types of seismic events were identified, which were interpreted to reflect a pattern of till deformation (Type A), basal sliding (Type B) and hydraulic transience (Type C) associated with stick-slip motion.

  12. Texture coding in the rat whisker system: slip-stick versus differential resonance.

    Directory of Open Access Journals (Sweden)

    Jason Wolfe

    2008-08-01

    Full Text Available Rats discriminate surface textures using their whiskers (vibrissae, but how whiskers extract texture information, and how this information is encoded by the brain, are not known. In the resonance model, whisker motion across different textures excites mechanical resonance in distinct subsets of whiskers, due to variation across whiskers in resonance frequency, which varies with whisker length. Texture information is therefore encoded by the spatial pattern of activated whiskers. In the competing kinetic signature model, different textures excite resonance equally across whiskers, and instead, texture is encoded by characteristic, nonuniform temporal patterns of whisker motion. We tested these models by measuring whisker motion in awake, behaving rats whisking in air and onto sandpaper surfaces. Resonant motion was prominent during whisking in air, with fundamental frequencies ranging from approximately 35 Hz for the long Delta whisker to approximately 110 Hz for the shorter D3 whisker. Resonant vibrations also occurred while whisking against textures, but the amplitude of resonance within single whiskers was independent of texture, contradicting the resonance model. Rather, whiskers resonated transiently during discrete, high-velocity, and high-acceleration slip-stick events, which occurred prominently during whisking on surfaces. The rate and magnitude of slip-stick events varied systematically with texture. These results suggest that texture is encoded not by differential resonant motion across whiskers, but by the magnitude and temporal pattern of slip-stick motion. These findings predict a temporal code for texture in neural spike trains.

  13. 26 CFR 1.904(f)-3 - Allocation of net operating losses and net capital losses.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 9 2010-04-01 2010-04-01 false Allocation of net operating losses and net....904(f)-3 Allocation of net operating losses and net capital losses. For rules relating to the allocation of net operating losses and net capital losses, see § 1.904(g)-3T. ...

  14. 29 CFR 4204.13 - Net income and net tangible assets tests.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Net income and net tangible assets tests. 4204.13 Section....13 Net income and net tangible assets tests. (a) General. The criteria under this section are that either— (1) Net income test. The purchaser's average net income after taxes for its three most recent...

  15. Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift

    Science.gov (United States)

    Barnhart, William D.; Murray, Jessica R.; Briggs, Richard W.; Gomez, Francisco; Miles, Charles P. J.; Svarc, Jerry L.; Riquelme, Sebástian; Stressler, Bryan J.

    2016-01-01

    Great subduction earthquakes are thought to rupture portions of the megathrust, where interseismic coupling is high and velocity-weakening frictional behavior is dominant, releasing elastic deformation accrued over a seismic cycle. Conversely, postseismic afterslip is assumed to occur primarily in regions of velocity-strengthening frictional characteristics that may correlate with lower interseismic coupling. However, it remains unclear if fixed frictional properties of the subduction interface, coseismic or aftershock-induced stress redistribution, or other factors control the spatial distribution of afterslip. Here we use interferometric synthetic aperture radar and Global Position System observations to map the distribution of coseismic slip of the 2015 Mw 8.3 Illapel, Chile, earthquake and afterslip within the first 38 days following the earthquake. We find that afterslip overlaps the coseismic slip area and propagates along-strike into regions of both high and moderate interseismic coupling. The significance of these observations, however, is tempered by the limited resolution of geodetic inversions for both slip and coupling. Additional afterslip imaged deeper on the fault surface bounds a discrete region of deep coseismic slip, and both contribute to net uplift of the Chilean Coastal Cordillera. A simple partitioning of the subduction interface into regions of fixed frictional properties cannot reconcile our geodetic observations. Instead, stress heterogeneities, either preexisting or induced by the earthquake, likely provide the primary control on the afterslip distribution for this subduction zone earthquake. We also explore the occurrence of coseismic and postseismic coastal uplift in this sequence and its implications for recent hypotheses concerning the source of permanent coastal uplift along subduction zones.

  16. Deformation rates in northern Cascadia consistent with slow updip propagation of deep interseismic creep

    Science.gov (United States)

    Bruhat, Lucile; Segall, Paul

    2017-10-01

    Interpretations of interseismic slip deficit on the northern Cascadia megathrust are complicated by an enigmatic `gap' between the downdip limit of the locked region, inferred from kinematic inversions of deformation rates, and the top of the episodic tremor and slip (ETS) zone. Recent inversions of global positioning system (GPS) and tide gauge/leveling data for shear stress rates acting on the megathrust found a ˜21 km locking depth with a steep slip-rate gradient at its base is required to fit the data. Previous studies have assumed the depth distribution of interseismic slip rate to be time invariant; however, steep slip-rate gradients could also result from the updip propagation of slip into the locked region. This study explores models where interseismic slip penetrates up into the locked zone. We consider the creeping region, corresponding to the gap and the ETS zone, as a quasi-static crack driven by the plate velocity at its downdip end. We derive a simple model that allows for crack propagation over time, and provides analytical expressions for stress drop within the crack, slip and slip rate on the fault. It is convenient to expand the non-singular slip-rate distribution in a sum of Chebyshev polynomials. Estimation of the polynomial coefficients is underdetermined, yet provides a useful way of testing particular solutions and provides bounds on the updip propagation rate. When applied to the deformation rates in northern Cascadia, best-fitting models reveal that a very slow updip propagation, between 30 and 120 m yr-1 along the fault, could explain the steep slip-rate profile, needed to fit the data. This work provides a new tool for estimating interseismic slip rates, between purely kinematic inversions and full physics-based modeling, allowing for the possibility for updip expansion of the creeping zone.

  17. Mass distribution of free insecticide-treated nets do not interfere with continuous net distribution in Tanzania.

    Science.gov (United States)

    Eze, Ikenna C; Kramer, Karen; Msengwa, Amina; Mandike, Renata; Lengeler, Christian

    2014-05-27

    To protect the most vulnerable groups from malaria (pregnant women and infants) the Tanzanian Government introduced a subsidy (voucher) scheme in 2004, on the basis of a public-private partnership. These vouchers are provided to pregnant women at their first antenatal care visit and mothers of infants at first vaccination. The vouchers are redeemed at registered retailers for a long-lasting insecticidal net against the payment of a modest top-up price. The present work analysed a large body of data from the Tanzanian National Voucher Scheme, focusing on interactions with concurrent mass distribution campaigns of free nets. In an ecologic study involving all regions of Tanzania, voucher redemption data for the period 2007-2011, as well as data on potential determinants of voucher redemption were analysed. The four outcome variables were: pregnant woman and infant voucher redemption rates, use of treated bed nets by all household members and by under- five children. Each of the outcomes was regressed with selected determinants, using a generalized estimating equation model and accounting for regional data clustering. There was a consistent improvement in voucher redemption rates over the selected time period, with rates >80% in 2011. The major determinants of redemption rates were the top-up price paid by the voucher beneficiary, the retailer- clinic ratio, and socio-economic status. Improved redemption rates after 2009 were most likely due to reduced top-up prices (following a change in policy). Redemption rates were not affected by two major free net distribution campaigns. During this period, there was a consistent improvement in net use across all the regions, with rates of up to 75% in 2011. The key components of the National Treated Nets Programme (NATNETS) seem to work harmoniously, leading to a high level of net use in the entire population. This calls for the continuation of this effort in Tanzania and for emulation by other countries with endemic malaria.

  18. INCIDENCE AND EPIDEMIOLOGY OF SLIPPED CAPITAL FEMORAL EPIPHYSIS

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    Oskar Zupanc

    2002-05-01

    Full Text Available Background. In the presented study we rewieved the epidemiology of slipped capital femoral epiphysis (SCFE. The aim of the study was to evaluate the incidence and epidemiology of the disease.Material and methods. Between the years 1970–1994, 156 consecutive patients were admitted to the Department of Orthopaedic Surgery in Ljubljana. The incidence was calculated using the attack rate method, i. e. the sum of annual incidences in each one year group. Mean age and boys : girls ratio were calculated. The affected side was also observed.Results. In our study the attack rate per thousand patients was 0.488 ‰ (0.474 ‰ for boys, 0.502 ‰ for girls. The risk of physiolysis was 1 : 2110 for boys, 1 : 1992 for girls and 1 : 2049 for both sexes. The average age at diagnosis was higher in boys (13.6 ± 1.6 [9.5–16.6] years than in girls (11.9 ± 1.43 [8–15.5] years (p < 0.001. There was no difference in boys : girls ratio (1 : 1. The left hip was affected first in 90 (58% patients which was significant (p < 0.05. There was the preponderance of the left hip being affected slightly more often in boys (30% than in girls (28%.Conclusions. The calculated incidence for both sexes in our population is 0.054 ‰. In the contrast to other studies the incidence of SCFE among our patients is lower for male patients. The boys : girls ratio is 1 : 1. The most common age at diagnosis is higher for boys than for the girls. The left hip is more frequently affected than the right one.

  19. Strike-slip faulting in the Inner California Borderlands, offshore Southern California.

    Science.gov (United States)

    Bormann, J. M.; Kent, G. M.; Driscoll, N. W.; Harding, A. J.; Sahakian, V. J.; Holmes, J. J.; Klotsko, S.; Kell, A. M.; Wesnousky, S. G.

    2015-12-01

    In the Inner California Borderlands (ICB), offshore of Southern California, modern dextral strike-slip faulting overprints a prominent system of basins and ridges formed during plate boundary reorganization 30-15 Ma. Geodetic data indicate faults in the ICB accommodate 6-8 mm/yr of Pacific-North American plate boundary deformation; however, the hazard posed by the ICB faults is poorly understood due to unknown fault geometry and loosely constrained slip rates. We present observations from high-resolution and reprocessed legacy 2D multichannel seismic (MCS) reflection datasets and multibeam bathymetry to constrain the modern fault architecture and tectonic evolution of the ICB. We use a sequence stratigraphy approach to identify discrete episodes of deformation in the MCS data and present the results of our mapping in a regional fault model that distinguishes active faults from relict structures. Significant differences exist between our model of modern ICB deformation and existing models. From east to west, the major active faults are the Newport-Inglewood/Rose Canyon, Palos Verdes, San Diego Trough, and San Clemente fault zones. Localized deformation on the continental slope along the San Mateo, San Onofre, and Carlsbad trends results from geometrical complexities in the dextral fault system. Undeformed early to mid-Pleistocene age sediments onlap and overlie deformation associated with the northern Coronado Bank fault (CBF) and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, we interpret the northern CBF to be inactive, and slip rate estimates based on linkage with the Holocene active Palos Verdes fault are unwarranted. In the western ICB, the San Diego Trough fault (SDTF) and San Clemente fault have robust linear geomorphic expression, which suggests that these faults may accommodate a significant portion of modern ICB slip in a westward temporal migration of slip. The SDTF offsets young sediments between the US/Mexico border and the

  20. Interaction between slip events, erosion and sedimentation along an active strike-slip fault: Insights from analog models

    Science.gov (United States)

    Chatton, M.; Malavieille, J.; Dominguez, S.; Manighetti, I.; Romano, C.; Beauprêtre, S.; Garembois, S.; Larroque, C.

    2012-04-01

    Recovering information on past (i.e., last 102-104 yrs) large earthquakes on faults is a challenge. The classical approach -especially used on strike-slip faults- consists in searching morphological markers such as river channels, streams, alluvial fans, ridges or terrace risers, etc, that would be offset by the fault, and measure these offsets by reconstructing the original position and shape of the markers. Combined with the dating of the offset markers, this morphotectonic paleoseismological approach may provide information on the slips and ages of the most recent earthquakes on the fault under study. Yet, the approach is complex as it depends on the recognition of unambiguous paired markers on either side of the fault. And our capability to recognize similar markers on either side of a fault in turn greatly depends on the 'evolution' that these markers may have sustained subsequently to their very first slip disruption. Did the repeating earthquake slip events modify their surface appearance? Did their morphology and position (ex: burying, destruction, modification, etc) evolve with the sedimentation and erosion that might have occurred during the fault history? Etc. These questions have rarely been approached for they are difficult to address in natural settings. And as we are unable to answer them in the natural cases that we study, the slip reconstructions that we provide are generally uncertain as they are likely based on an incomplete or biased record of the past fault slips. Therefore, the objective of our work is to contribute to better understand and document the nature and 'evolution' of the morphological markers that are commonly used in morphotectonic and paleoseismological analyses, especially along strike-slip faults. We approach these questions experimentally. We have developed an original experimental set-up made to simulate repeated slip events on a strike-slip fault placed in a wet environment sustaining sedimentation and erosion. The fault

  1. Nonoperative treatment of slipped capital femoral epiphysis: a scientific study

    Science.gov (United States)

    2011-01-01

    Background Treatment of the Slipped Capital Femoral Epiphysis remains a cause of concern due to the fact that the true knowledge of the etiopathogeny is unknown, as well as one of its major complications: chondrolysis. The conservative treatment remains controversial; it has been overlooked in the studies and subjected to intense criticism. The purpose of this study is to investigate the results of treatment on the hip of patients displaying slipped capital femoral epiphysis, using the plaster cast immobilization method and its link to chondrolysis. Methods The research was performed based on the study of the following variables: symptomatology, and the degree of slipping. A hip spica cast and bilateral short/long leg casts in abduction, internal rotation with anti-rotational bars were used for immobilizing the patient's hip for twelve weeks. Statistical analysis was accomplished by Wilcoxon's marked position test and by the Fisher accuracy test at a 5% level. Results A satisfactory result was obtained in the acute group, 70.5%; 94%; in the chronic group (chronic + acute on chronic). Regarding the degree of the slipping, a satisfactory result was obtained in 90.5% of hips tested with a mild slip; in 76% with moderate slip and 73% in the severe slip. The statistical result revealed that a significant improvement was found for flexion (p = 0.0001), abduction (p = 0.0001), internal rotation (p = 0.0001) and external rotation (p = 0.02). Chondrolysis was present in 11.3% of the hips tested. One case of pseudoarthrosis with aseptic capital necrosis was presented. There was no significant variation between age and chondrolysis (p = 1.00).Significant variation between gender/non-white patients versus chondrolysis (p = 0.031) and (p = 0.037), respectively was verified. No causal association between plaster cast and chondrolysis was observed (p = 0.60). In regard to the symptomatology group and the slip degree versus chondrolysis, the p value was not statistically

  2. Nonoperative treatment of slipped capital femoral epiphysis: a scientific study

    Directory of Open Access Journals (Sweden)

    Pinheiro Pedro

    2011-02-01

    Full Text Available Abstract Background Treatment of the Slipped Capital Femoral Epiphysis remains a cause of concern due to the fact that the true knowledge of the etiopathogeny is unknown, as well as one of its major complications: chondrolysis. The conservative treatment remains controversial; it has been overlooked in the studies and subjected to intense criticism. The purpose of this study is to investigate the results of treatment on the hip of patients displaying slipped capital femoral epiphysis, using the plaster cast immobilization method and its link to chondrolysis. Methods The research was performed based on the study of the following variables: symptomatology, and the degree of slipping. A hip spica cast and bilateral short/long leg casts in abduction, internal rotation with anti-rotational bars were used for immobilizing the patient's hip for twelve weeks. Statistical analysis was accomplished by Wilcoxon's marked position test and by the Fisher accuracy test at a 5% level. Results A satisfactory result was obtained in the acute group, 70.5%; 94%; in the chronic group (chronic + acute on chronic. Regarding the degree of the slipping, a satisfactory result was obtained in 90.5% of hips tested with a mild slip; in 76% with moderate slip and 73% in the severe slip. The statistical result revealed that a significant improvement was found for flexion (p = 0.0001, abduction (p = 0.0001, internal rotation (p = 0.0001 and external rotation (p = 0.02. Chondrolysis was present in 11.3% of the hips tested. One case of pseudoarthrosis with aseptic capital necrosis was presented. There was no significant variation between age and chondrolysis (p = 1.00.Significant variation between gender/non-white patients versus chondrolysis (p = 0.031 and (p = 0.037, respectively was verified. No causal association between plaster cast and chondrolysis was observed (p = 0.60. In regard to the symptomatology group and the slip degree versus chondrolysis, the p value was not

  3. g-Jitter mixed convective slip flow of nanofluid past a permeable stretching sheet embedded in a Darcian porous media with variable viscosity.

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    Mohammed J Uddin

    Full Text Available The unsteady two-dimensional laminar g-Jitter mixed convective boundary layer flow of Cu-water and Al2O3-water nanofluids past a permeable stretching sheet in a Darcian porous is studied by using an implicit finite difference numerical method with quasi-linearization technique. It is assumed that the plate is subjected to velocity and thermal slip boundary conditions. We have considered temperature dependent viscosity. The governing boundary layer equations are converted into non-similar equations using suitable transformations, before being solved numerically. The transport equations have been shown to be controlled by a number of parameters including viscosity parameter, Darcy number, nanoparticle volume fraction, Prandtl number, velocity slip, thermal slip, suction/injection and mixed convection parameters. The dimensionless velocity and temperature profiles as well as friction factor and heat transfer rates are presented graphically and discussed. It is found that the velocity reduces with velocity slip parameter for both nanofluids for fluid with both constant and variable properties. It is further found that the skin friction decreases with both Darcy number and momentum slip parameter while it increases with viscosity variation parameter. The surface temperature increases as the dimensionless time increases for both nanofluids. Nusselt numbers increase with mixed convection parameter and Darcy numbers and decreases with the momentum slip. Excellent agreement is found between the numerical results of the present paper with published results.

  4. Motion of a Deformed Sphere with Slip in Creeping Flows

    Science.gov (United States)

    Benard, Andre; Jia, Liping; Petty, Charles

    2004-11-01

    An analytical solution for the motion of a slightly deformed sphere in creeping flows with the assumption of slip on the particle surface is presented. Explicit expressions are obtained for the hydrodynamic force and torque exerted by the fluid on the deformed sphere. A perturbation method, based on previous work done by Brenner [1964] and Lamb[1945], is used to solve for the motion of a fluid influenced by the presence of a deformed sphere. Slip is assumed at the surface of the particle. Hydrodynamic force and torque exerted by the fluid on the deformed sphere are expressed explicitly for a translational and rotational deformed sphere. The equation governing the motion and orientation of a spheroid induced by homogenous flows is also presented. This evolution equation for the orientation of the spheroid is similar to the equation derived by Jeffery [1922]. Solutions of this equation show that the period of rotation of the particle with slip is longer than for the same particle without slip. Furthermore, when the slip coefficient is sufficiently low, the particle rotates to a fixed angle that corresponds to a quasi-steady state in the flow. REFERENCES Brenner, H. 1964 The Stokes resistance of a slightly deformed sphere. Chemical Engineering Science 19, 519-539 Jeffery, G.B.1922 The motion of ellipsoidal particles immersed in a viscous fluid. Proc. Soc. Lond. Math., 102, 161-179 Lamb, H. 1945 Hydrodynamics, sixth version, Dover, New York, U.S.A

  5. Soil slips and debris flows on terraced slopes

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    G. B. Crosta

    2003-01-01

    Full Text Available Terraces cover large areas along the flanks of many alpine and prealpine valleys. Soil slips and soil slips-debris flows are recurrent phenomena along terraced slopes. These landslides cause damages to people, settlements and cultivations. This study investigates the processes related to the triggering of soil slip-debris flows in these settings, analysing those occurred in Valtellina (Central Alps, Italy on November 2000 after heavy prolonged rainfalls. 260 landslides have been recognised, mostly along the northern valley flank. About 200 soil slips and slumps occurred in terraced areas and a third of them evolved into debris flows. Field work allowed to recognise the settings at soil slip-debris flow source areas. Landslides affected up to 2.5 m of glacial, fluvioglacial and anthropically reworked deposits overlying metamorphic basement. Laboratory and in situ tests allowed to characterise the geotechnical and hydraulic properties of the terrains involved in the initial failure. Several stratigraphic and hydrogeologic factors have been individuated as significant in determining instabilities on terraced slopes. They are the vertical changes of physical soil properties, the presence of buried hollows where groundwater convergence occurs, the rising up of perched groundwater tables, the overflow and lateral infiltration from superficial drainage network, the runoff concentration by means of pathways and the insufficient drainage of retaining walls.

  6. Measurement of Quantum Phase-Slips in Josephson Junction Chains

    Science.gov (United States)

    Guichard, Wiebke

    2011-03-01

    Quantum phase-slip dynamics in Josephson junction chains could provide the basis for the realization of a new type of topologically protected qubit or for the implementation of a new current standard. I will present measurements of the effect of quantum phase-slips on the ground state of a Josephson junction chain. We can tune in situ the strength of the phase-slips. These phase-slips are the result of fluctuations induced by the finite charging energy of each junction in the chain. Our measurements demonstrate that a Josephson junction chain under phase bias constraint behaves in a collective way. I will also show evidence of coherent phase-slip interference, the so called Aharonov-Casher effect. This phenomenon is the dual of the well known Aharonov-Bohm interference. In collaboration with I.M. Pop, Institut Neel, C.N.R.S. and Universite Joseph Fourier, BP 166, 38042 Grenoble, France; I. Protopopov, L. D. Landau Institute for Theoretical Physics, Kosygin str. 2, Moscow 119334, Russia and Institut fuer Nanotechnologie, Karlsruher Institut fuer Technologie, 76021 Karlsruhe, Germany; and F. Lecocq, Z. Peng, B. Pannetier, O. Buisson, Institut Neel, C.N.R.S. and Universite Joseph Fourier. European STREP MIDAS, ANR QUANTJO.

  7. Scaling analysis for the investigation of slip mechanisms in nanofluids

    Directory of Open Access Journals (Sweden)

    Savithiri S

    2011-01-01

    Full Text Available Abstract The primary objective of this study is to investigate the effect of slip mechanisms in nanofluids through scaling analysis. The role of nanoparticle slip mechanisms in both water- and ethylene glycol-based nanofluids is analyzed by considering shape, size, concentration, and temperature of the nanoparticles. From the scaling analysis, it is found that all of the slip mechanisms are dominant in particles of cylindrical shape as compared to that of spherical and sheet particles. The magnitudes of slip mechanisms are found to be higher for particles of size between 10 and 80 nm. The Brownian force is found to dominate in smaller particles below 10 nm and also at smaller volume fraction. However, the drag force is found to dominate in smaller particles below 10 nm and at higher volume fraction. The effect of thermophoresis and Magnus forces is found to increase with the particle size and concentration. In terms of time scales, the Brownian and gravity forces act considerably over a longer duration than the other forces. For copper-water-based nanofluid, the effective contribution of slip mechanisms leads to a heat transfer augmentation which is approximately 36% over that of the base fluid. The drag and gravity forces tend to reduce the Nusselt number of the nanofluid while the other forces tend to enhance it.

  8. The viscous slip coefficient for a binary gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Knackfuss, Rosenei F. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Centro de Ciencias Naturais e Exatas. Dept. de Matematica], e-mail: rfknackfuss@gmail.com

    2009-07-01

    For a moderately small rarefaction, the Navier-Stokes equations are associated with of the slip boundary condition, i e the velocity of the gas on the surface is different from zero at the surface, but its tangential component, depends on the profile distribution of velocity and temperature near the surface. The slip for the velocity profile near the surface is determined by the viscous slip coefficient. The viscous slip coefficient can be determined solving the equation of the Boltzmann or the kinetic equations which are simplified forms of Boltzmann equation with respect to the operator of collision. For this reason, in this work is presented the derivation of the solution of the viscous-slip problem for the mixtures of two noble gases, based on the McCormack model that is developed in terms of an analytical version of the discrete ordinates method has been applied with excellent results, to derive solutions to several problems in rarefied gas dynamics. To complete the problem, include the gas-surface interaction, based on the model of Cercignani-Lampis, which, unlike the model of Maxwell, has two accommodation coefficients: the coefficient of accommodation of tangential moment and the energy accommodation coefficient kinetics due to normal component of velocity. (author)

  9. Efficient Numerical Modeling of 3D, Half-Space, Slow-Slip and Quasi-Dynamic Earthquake Ruptures

    Science.gov (United States)

    Bradley, A. M.; Segall, P.

    2011-12-01

    Motivated by the hypothesis that dilatancy plays a critical role in faulting in subduction zones, we are developing FDRA2 (Fault Dynamics with the Radiation-damping Approximation), a software package to simulate three-dimensional quasi-dynamic faulting that includes rate-state friction, thermal pressurization, and dilatancy (following Segall and Rice [1995]) in a finite-width shear zone. This work builds on the two-dimensional simulations performed by FDRA1 (Bradley and Segall [AGU 2010], Segall and Bradley [submitted]). These simulations show that at lower background effective normal stress (\\bar σ), slow slip events occur spontaneously, whereas at higher \\bar σ , slip is inertially limited. At intermediate \\bar σ , dynamic events are followed by quiescent periods and then long durations of repeating slow slip events. Models with depth-dependent properties produce sequences similar to those observed in Cascadia. Like FDRA1, FDRA2 solves partial differential equations in pressure and temperature on profiles normal to the fault. The diffusion equations are discretized in space using finite differences on a nonuniform mesh having greater density near the fault. The full system of equations is a semiexplicit index-1 differential algebraic equation (DAE) in slip, slip rate, state, fault zone porosity, pressure, and temperature. We integrate state, porosity, and slip explicitly; solve the momentum balance equation on the fault for slip rate; and integrate pressure and temperature implicitly. Adaptive time steps are limited by accuracy and the stability criterion governing explicit integration of hyperbolic, but not the more stringent one governing parabolic, PDE. To compute elasticity in a 3D half-space, FDRA2 compresses the large, dense matrix arising from the boundary element method using an H-matrix. The work to perform a matrix-vector product scales almost linearly, rather than quadratically, in the number of fault cells. A new technique to relate the error

  10. The Transient Behavior of Aseismic Slip Along the Creeping Section of the North Anatolian Fault, Turkey

    Science.gov (United States)

    Jolivet, R.; Rousset, B.; Simons, M.; Lasserre, C.; Riel, B. V.; Milillo, P.; Cakir, Z.

    2014-12-01

    The ongoing development of constellations of Synthetic Aperture Radar (SAR) satellites with short repeat time acquisitions allows to explore the behavior of active faults with an unprecedented temporal and spatial resolution. The improvement from monthly to daily repeat times sheds a new light on the dynamics of near-surface fault creep along continental faults, which has been shown to exhibit various temporal behaviors, from persistent slow silent slip to discrete episodes of aseismic slip. Along the North Anatolian Fault (NAF), an 80 km-long section is creeping at least since the 1944, M7.3 earthquake near Ismetpasa, Turkey. Recent geodetic measurements suggest an average creep rate of about half the total slip rate accommodated by the NAF (8±3 mm/yr vs. 22±3 mm/yr). In addition, an effective bi-modal distribution of frictional properties along fault dip (rate-strengthening from the surface to 5-7 km-depth and rate-weakening down to the locking depth) can explain the persistent creep rate and the extent of past ruptures. We take advantage of the dense set of SAR images acquired by the Cosmo-SkyMed™ (ASI) constellation over the creeping section of the NAF to quantify, with a high spatial and temporal resolution, the distribution of aseismic slip along strike and its evolution between August 2013 and June 2014. We compute 1000+ interferograms from 350+ radar acquisitions over 7 tracks using the ISCE software (JPL). We use the Generic InSAR Analysis Toolbox (GIAnT) and the PyAPS library to correct interferograms from the propagation delays due to the stratification of the troposphere, predicted using the ERA-Interim (ECMWF) re-analysis. We use the New Small Baseline (NSBAS) method to derive the spatial and temporal evolution of the near-fault displacements independently for each track. Our results suggest the fault does not creep steadily over the 2013-2014 period but rather releases strain through discrete aseismic events we refer to as bursts of creep. In

  11. TimeNET Optimization Environment

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    Christoph Bodenstein

    2015-12-01

    Full Text Available In this paper a novel tool for simulation-based optimization and design-space exploration of Stochastic Colored Petri nets (SCPN is introduced. The working title of this tool is TimeNET Optimization Environment (TOE. Targeted users of this tool are people modeling complex systems with SCPNs in TimeNET who want to find parameter sets that are optimal for a certain performance measure (fitness function. It allows users to create and simulate sets of SCPNs and to run different optimization algorithms based on parameter variation. The development of this tool was motivated by the need to automate and speed up tests of heuristic optimization algorithms to be applied for SCPN optimization. A result caching mechanism is used to avoid recalculations.

  12. Plant water stress effects on the net dispersal rate of the insect vector Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) and movement of its egg parasitoid, Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae)

    Science.gov (United States)

    Homalodisca vitripennis, one of the main vectors of Xylella fastidiosa, is associated with citrus plantings in California, USA. Infested citrus orchards act as a source of vectors to adjacent vineyards where X. fastidiosa causes Pierce’s disease (PD). An analysis of the pattern and rate of movement ...

  13. Development of anti-slip sustainable tiles from agricultural waste

    Science.gov (United States)

    Zulkefli, Zainordin Firdaus; Zainol, Mohd Remy Rozainy Mohd Arif; Osman, Norhayati

    2017-04-01

    In general of 80% the human activities is located in the building. Buildings constructed should be in line with full functions and optimum safety features. Aspects to be emphasized is the slip on the floor of the building. The selection of tiles must have anti-slip characteristics and achieve standard strength stress. This study is conducted to develop anti-slip tiles modification using agricultural waste. The material used is agricultural waste such rice husks, palm fibre and saw dusk mixed into the clay and then baked at a temperature of 900-1185 C °. Agricultural waste mixture ratio is 5%, 10% and 15%. The samples of tiles are produced for experiments. The results of agricultural waste tiles show that the strength is higher than standard strength, the water absorption less than standard tiles and pendulum value test is exceeds 36.

  14. Slip systems, dislocation boundaries and lattice rotations in deformed metals

    DEFF Research Database (Denmark)

    Winther, Grethe

    2009-01-01

    Metals are polycrystals and consist of grains, which are subdivided on a finer scale upon plastic deformation due to formation of dislocation boundaries. The crystallographic alignment of planar dislocation boundaries in face centred cubic metals, like aluminium and copper, deformed to moderate...... slip systems. Actual prediction of the dislocation boundary alignment has become possible through establishment of general relations between slip systems and dislocation boundary planes. The practical relevance of these relations has been exemplified by applying them as a basis for further prediction...... of the mechanical anisotropy of rolled sheets. The rotation of the crystallographic lattice in each grain during deformation also exhibits grain orientation dependence, originating from the slip systems. A combined analysis of dislocation boundaries and lattice rotations concludes that the two phenomena are coupled...

  15. Slip-stick excitation and travelling waves excite silo honking

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    Warburton Katarzyna

    2017-01-01

    Full Text Available Silo honking is the harmonic sound generated by the discharge of a silo filled with a granular material. In industrial storage silos, the acoustic emission during discharge of PET-particles forms a nuisance for the environment and may ultimately result in structural failure. This work investigates the phenomenon experimentally using a laboratory-scale silo, and successfully correlates the frequency of the emitted sound with the periodicity of the mechanical motion of the grains. The key driver is the slip-stick interaction between the wall and the particles, characterized as a wave moving upwards through the silo. A quantitative correlation is established for the first time between the frequency of the sound, measured with an electret microphone, and the slip-frequency, measured with a high-speed camera. In the lower regions of the tube, both the slip-stick motion and the honking sound disappear.

  16. Creep and slip: Seismic precursors to the Nuugaatsiaq landslide (Greenland)

    Science.gov (United States)

    Poli, Piero

    2017-09-01

    Precursory signals to material's failure are predicted by numerical models and observed in laboratory experiments or using field data. These precursory signals are a marker of slip acceleration on weak regions, such as crustal faults. Observation of these precursory signals of catastrophic natural events, such as earthquakes and landslides, is necessary for improving our knowledge about the physics of the nucleation process. Furthermore, observing such precursory signals may help to forecast these catastrophic events or reduce their hazard. I report here the observation of seismic precursors to the Nuugaatsiaq landslide in Greenland. Time evolution of the detected precursors implies that an aseismic slip event is taking place for hours before the landslide, with an exponential increase of slip velocity. Furthermore, time evolution of the precursory signals' amplitude sheds light on the evolution of the fault physics during the nucleation process.

  17. Atomistic Determination of Cross-Slip Pathway and Energetics

    DEFF Research Database (Denmark)

    Rasmussen, Torben; Jacobsen, Karsten Wedel; Leffers, Torben

    1997-01-01

    plane. The transition state and activation energy for cross slip as well as the energies of the involved dislocation constrictions are determined. One constriction has a negative energy compared to parallel partials. The energy vs splitting width for recombination of parallel partials into a perfect......The mechanism for cross slip of a screw dislocation in Cu is determined by atomistic simulations that only presume the initial and final states of the process. The dissociated dislocation constricts in the primary plane and redissociates into the cross-slip plane while still partly in the primary...... dislocation is determined. The breakdown of linear elasticity theory for small splitting widths is studied. [S0031-9007(97)04444-X]....

  18. Implementing NetScaler VPX

    CERN Document Server

    Sandbu, Marius

    2014-01-01

    An easy-to-follow guide with detailed step-by step-instructions on how to implement the different key components in NetScaler, with real-world examples and sample scenarios.If you are a Citrix or network administrator who needs to implement NetScaler in your virtual environment to gain an insight on its functionality, this book is ideal for you. A basic understanding of networking and familiarity with some of the different Citrix products such as XenApp or XenDesktop is a prerequisite.

  19. Net4Care PHMR Library

    DEFF Research Database (Denmark)

    2014-01-01

    The Net4Care PHMR library contains a) A GreenCDA approach for constructing a data object representing a PHMR document: SimpleClinicalDocument, and b) A Builder which can produce a XML document representing a valid Danish PHMR (following the MedCom profile) document from the SimpleClinicalDocument......The Net4Care PHMR library contains a) A GreenCDA approach for constructing a data object representing a PHMR document: SimpleClinicalDocument, and b) A Builder which can produce a XML document representing a valid Danish PHMR (following the MedCom profile) document from the Simple...

  20. Pro DLR in NET 4

    CERN Document Server

    Wu, Chaur

    2011-01-01

    Microsoft's Dynamic Language Runtime (DLR) is a platform for running dynamic languages such as Ruby and Python on an equal footing with compiled languages such as C#. Furthermore, the runtime is the foundation for many useful software design and architecture techniques you can apply as you develop your .NET applications. Pro DLR in .NET 4 introduces you to the DLR, showing how you can use it to write software that combines dynamic and static languages, letting you choose the right tool for the job. You will learn the core DLR components such as LINQ expressions, call sites, binders, and dynami

  1. Hierarchies in Coloured Petri Nets

    DEFF Research Database (Denmark)

    Huber, Peter; Jensen, Kurt; Shapiro, Robert M.

    1991-01-01

    The paper shows how to extend Coloured Petri Nets with a hierarchy concept. The paper proposes five different hierarchy constructs, which allow the analyst to structure large CP-nets as a set of interrelated subnets (called pages). The paper discusses the properties of the proposed hierarchy...... constructs, and it illustrates them by means of two examples. The hierarchy constructs can be used for theoretical considerations, but their main use is to describe and analyse large real-world systems. All of the hierarchy constructs are supported by the editing and analysis facilities in the CPN Palette...

  2. Effects of Acoustic Waves on Stick—Slip Behavior in Sheared Granular Media With Implications to Dynamic Earthquake Triggering and Slow Slip

    Science.gov (United States)

    Johnson, Paul; Marone, Chris; Knuth, Matt; Kaproth, Bryan; Carpenter, Brett; Behringer, Bob; Guyer, Robert; Le Bas, Pierre-Yves; Griffa, Michele; Carmeliet, Jan

    2010-05-01

    To better understand the physics of dynamic triggering and the influence of dynamic stressing on earthquake recurrence, we are conducting laboratory studies of stick—slip in granular media with and without applied acoustic waves. In our 3-D experiments, glass beads are used to simulate granular fault zone wear material, sheared in a double-direct configuration under constant normal stress, while subject to transient or continuous perturbations by acoustic waves. We find that the horizontal stress applied plays a crucial role in the response of the glass beads to applied waves. Under smaller normal stress (2MPa), and subject to wave amplitudes of >10-6 strain, we observe induced slow (silent) slip and tremor. Under moderate normal stress (4 MPa) and subject to >10-6 strain amplitude we observe both instantaneous and delayed triggering. Waves also cause significant disruption in the recurrence rate. The effects of waves are observed for many major-event cycles after wave excitation ceases, indicating a strain memory of waves in the granular material. Under slightly larger horizontal stress (5MPa), if strain amplitudes exceed 10-6, we observe instantaneous triggering followed by slow dynamics—the shear modulus recovers linearly with the-logarithm-of-time back to equilibrium. Slow dynamics is a classical elastic nonlinear (anelastic) behavior observed in acoustical experiments with rock samples in the lab as well as in Earth. Wave-induced disruption of periodic stick—slip is linked to failure of granular force chains. In 2-D experiments we are applying photoelastic discs in stick—slip measurements in order to visualize the evolution of the force chain network. Photoelastic measurements provide insight into failure, and in particular small adjustments in the force chains network that presage failure. A phenomenological model similar to Knopoff-Burridge shows the same general behaviors as well. In a companion paper, we show model results emplying a DEM approach

  3. Back analysis of fault-slip in burst prone environment

    Science.gov (United States)

    Sainoki, Atsushi; Mitri, Hani S.

    2016-11-01

    In deep underground mines, stress re-distribution induced by mining activities could cause fault-slip. Seismic waves arising from fault-slip occasionally induce rock ejection when hitting the boundary of mine openings, and as a result, severe damage could be inflicted. In general, it is difficult to estimate fault-slip-induced ground motion in the vicinity of mine openings because of the complexity of the dynamic response of faults and the presence of geological structures. In this paper, a case study is conducted for a Canadian underground mine, herein called "Mine-A", which is known for its seismic activities. Using a microseismic database collected from the mine, a back analysis of fault-slip is carried out with mine-wide 3-dimensional numerical modeling. A back analysis is conducted to estimate the physical and mechanical properties of the causative fracture or shear zones. One large seismic event has been selected for the back analysis to detect a fault-slip related seismic event. In the back analysis, the shear zone properties are estimated with respect to moment magnitude of the seismic event and peak particle velocity (PPV) recorded by a strong ground motion sensor. The estimated properties are then validated through comparison with peak ground acceleration recorded by accelerometers. Lastly, ground motion in active mining areas is estimated by conducting dynamic analysis with the estimated values. The present study implies that it would be possible to estimate the magnitude of seismic events that might occur in the near future by applying the estimated properties to the numerical model. Although the case study is conducted for a specific mine, the developed methodology can be equally applied to other mines suffering from fault-slip related seismic events.

  4. Histological, histochemical and ultrastructural study of slipped capital femoral epiphysis.

    Science.gov (United States)

    Tresoldi, I; Modesti, A; Dragoni, M; Potenza, V; Ippolito, E

    2017-04-01

    The purpose of our study was to investigate the histological, histochemical and ultrastructural aspects of the proximal femoral growth plate in slipped capital femoral epiphysis (SCFE). Eight core biopsies of the proximal femoral growth plate were performed during in situ epiphysiodesis in patients with SCFE that was at the pre-slipping stage in two cases and at the mild slipping stage (Southwick angle femoral growth plate was thicker than normal in the SCFE cases, and the 3:1 ratio between the thickness of the resting zone and the other zones of the plate was reversed. Chondrocytes of the proliferating, maturation, hypertrophic and degenerating zones were arranged in large clusters rather than in columns, which were separated by loose fibrillary septae that appeared moderately alcian blue positive and metachromatic. The collagen fibrils of the longitudinal septae were uniformly thin, measuring about 200 Å, whereas in the normal plate collagen fibrils were in the range of 300 to 1200 Å in thickness. Chondrocytes were elongated and smaller than normal, with a dark cytoplasm. In the degenerating zone, mineralisation of the longitudinal and transversal septae was scanty and enchondral ossification was impaired, with a few small osteoblasts forming thin bone trabeculae on the cartilage septae of the degenerating zone. In SCFE, the proximal femoral growth plate undergoes several histological, histochemical and ultrastructural changes that precede slipping of the epiphysis since they are already present at a pre-slipping stage of the disease. The loss of solidity of the extracellular matrix and the disarrangement of the normal architecture of the physis very likely cause the consequent slipping of the proximal femoral epiphysis. SCFE aetiology remains unknown.

  5. Slips, trips and falls at a chemical manufacturing company.

    Science.gov (United States)

    Swaen, G; Burns, C J; Collins, J J; Bodner, K M; Dizor, J F; Craun, B A; Bonner, E M

    2014-03-01

    Slips, trips and falls (STF) are a major cause of workplace injury. To examine risk factors for STF at a large US chemical manufacturing company. We conducted a case-control study of occupational STF. Cases were identified from company injury records between 1 April 2009 and 1 May 2011. Four controls per case were randomly selected from all active company workers employed during the same time. Data were collected through a questionnaire and from company medical examinations. Logistic regression was used to calculate odds ratio (OR) and 95% confidence intervals (95% CI) for personal, environmental and health-related risk factors for STF. There were 74 cases and 309 controls. The response rate was 65% for the cases and 68% for the controls. Most STF were unrelated to production activities. When examining all factors in a logistic regression model, increased OR were observed for increased body mass index (OR = 1.44, 95% CI: 1.03-2.02), having arthritis (OR = 2.11, 95% CI: 1.01-4.37), lack of exercise (OR = 2.25, 95% CI: 1.01-5.05), carrying materials (OR = 3.01, 95% CI: 1.41-6.43) and being female (OR = 2.46, 95% CI: 1.17-5.19). Reduced risk of STF was observed for never having smoked (OR = 0.48, 95% CI: 0.24-0.95), long service (OR = 0.53, 95% CI: 0.34-0.81) and persons working over 8h a day (OR = 0.42, 95% CI: 0.20-0.88). Risk factors for STF in a large US chemical company are similar to those reported from other workplaces, but we found that staying fit and healthy is important for reducing risk.

  6. Generalized Net Model of Brevibacterium flavul 22LD Fermentation Process

    Directory of Open Access Journals (Sweden)

    Olympia Roeva

    2005-04-01

    Full Text Available In order to render the specific peculiarities of the fermentation processes, as well as to avoid the complexity of mathematical description with systems of differential equations, the elaboration of some new methods and approaches for their modelling and control is predetermined. As a new, alternative approach for modelling of fermentation processes, an application of generalized nets is presented in this paper. The theory of generalized nets is applied to the fermentation process of Brevibacterium flavul 22LD for L-lysine production. A generalized net model of considered process is developed. For comparison and completeness, model with differential equations is also provided. The generalized nets model developed for the fed-batch cultivation of Brevibacterium flavul 22LD allows changing the concentration of the feeding solution and the aeration rate. In this way some inhibition effects are prevented and a possibility for optimal carrying out of the considered fermentation process is provided.

  7. Phase-slip centers in superconducting indium microbridges

    Science.gov (United States)

    Weissbrod, H.; Huebener, R. P.; Clauss, W.

    1987-10-01

    Measurement is made of the transition to the resistive state of nearly one-dimensional superconducting microbridges of indium. The length of the microbridges ranged from 30 to 130 µm. The experiments concentrated in particular on the onset and temperature dependence of the hysteresis of the voltage-current characteristic, the temperature dependence of the excess current, and the equivalent normal length of the phase-slip centers generated during the resistive transition. The results are in good agreement with the dynamic model of a phase-slip center proposed by Kadin, Smith, and Skocpol.

  8. Phase-slip centers in superconducting indium microbridges

    Energy Technology Data Exchange (ETDEWEB)

    Weissbrod, H.; Huebener, R.P.; Clauss, W.

    1987-10-01

    Measurement is made of the transition to the resistive state of nearly one-dimensional superconducting microbridges of indium. The length of the microbridges ranged from 30 to 130 ..mu..m. The experiments concentrated in particular on the onset and temperature dependence of the hysteresis of the voltage-current characteristic, the temperature dependence of the excess current, and the equivalent normal length of the phase-slip centers generated during the resistive transition. The results are in good agreement with the dynamic model of a phase-slip center proposed by Kadin, Smith, and Skocpol.

  9. Comment on Cercignani's second-order slip coefficient

    Science.gov (United States)

    Hadjiconstantinou, Nicolas G.

    2003-08-01

    Cercignani's second-order slip model has been neglected over the years, perhaps due to Sreekanth's claim that it cannot fit his experimental data. In this paper we show that Sreekanth's claim was based on an incorrect interpretation of this model. We also show that Cercignani's second-order slip model, when modified and used appropriately, is in good agreement with solutions of the Boltzmann equation for a hard-sphere gas for a wide range of rarefaction. Given its simplicity, we expect this model to be a valuable tool for describing isothermal micro- and nanoscale flows to the extent that the hard-sphere approximation is appropriate.

  10. Slip divergence of water flow in graphene nanochannels: the role of chirality

    DEFF Research Database (Denmark)

    Wagemann, Enrique; Oyarzua, Elton; Walther, Jens Honore

    2017-01-01

    Graphene has attracted considerable attention due to its characteristics as a 2D material and its fascinating properties, providing a potential building block for nanofabrication. In nanochannels the solid-liquid interface plays a non-negligible role in determining the fluid dynamics. Therefore......, for an optimal design of nanofluidic devices, a comprehensive understanding of the slippage in a water flow confined between graphene walls is important. In nanoconfinement, experimental and computational studies have found the slip length to increase nonlinearly when the shear rate is larger than a critical...

  11. Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal

    OpenAIRE

    Galetzka, John; Melgar, Diego; Genrich, Joachim F.; Geng, Jianghui; Owen, Susan; Lindsey, Eric O.; Xu, Xiaohua; Bock, Yehuda; Avouac, Jean-Philippe; Adhikari, Lok Bijaya; Upreti, Bishal Nath; Pratt-Sitaula, Beth; Bhattarai, Tara Nidhi; Sitaula, Bhairab P.; Moore, Angelyn

    2015-01-01

    This is the author accepted manuscript. The final version is available from AAAS via http://dx.doi.org/10.1126/science.aac6383 Detailed geodetic imaging of earthquake rupture enhances our understanding of earthquake physics and induced ground shaking. The April 25, 2015 Mw 7.8 Gorkha, Nepal earthquake is the first example of a large continental megathrust rupture beneath a high-rate (5 Hz) GPS network. We use GPS and InSAR data to model the earthquake rupture as a slip pulse of ~20 km widt...

  12. D.NET case study

    International Development Research Centre (IDRC) Digital Library (Canada)

    lremy

    developing products, marketing tools and building capacity of the grass root telecentre workers. D.Net recognized that it had several ideas worth developing into small interventions that would make big differences, but resource constraints were a barrier for scaling-up these initiatives. More demands, limited resources.

  13. Surgery for GEP-NETs

    DEFF Research Database (Denmark)

    Knigge, Ulrich; Hansen, Carsten Palnæs

    2012-01-01

    Surgery is the only treatment that may cure the patient with gastroentero-pancreatic (GEP) neuroendocrine tumours (NET) and neuroendocrine carcinomas (NEC) and should always be considered as first line treatment if R0/R1 resection can be achieved. The surgical and interventional procedures for GEP...

  14. Net Neutrality in the Netherlands

    NARCIS (Netherlands)

    van Eijk, N.

    2014-01-01

    The Netherlands is among the first countries that have put specific net neutrality standards in place. The decision to implement specific regulation was influenced by at least three factors. The first was the prevailing social and academic debate, partly due to developments in the United States. The

  15. Complexity Metrics for Workflow Nets

    DEFF Research Database (Denmark)

    Lassen, Kristian Bisgaard; van der Aalst, Wil M.P.

    2009-01-01

    Process modeling languages such as EPCs, BPMN, flow charts, UML activity diagrams, Petri nets, etc.\\ are used to model business processes and to configure process-aware information systems. It is known that users have problems understanding these diagrams. In fact, even process engineers and system...

  16. High success rates of sedation-free brain MRI scanning in young children using simple subject preparation protocols with and without a commercial mock scanner-the Diabetes Research in Children Network (DirecNet) experience

    Energy Technology Data Exchange (ETDEWEB)

    Barnea-Goraly, Naama; Marzelli, Matt J.; Mazaika, Paul K. [Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford, CA (United States); Weinzimer, Stuart A. [Yale University, Pediatric Endocrinology, New Haven, CT (United States); Ruedy, Katrina J.; Beck, Roy W.; Kollman, Craig; Cheng, Peiyao [Jaeb Center for Health Research, Tampa, FL (United States); Mauras, Nelly; Fox, Larry [Nemours Children' s Clinic, Pediatric Endocrinology, Jacksonville, FL (United States); Aye, Tandy [Stanford University, Department of Pediatrics, Stanford, CA (United States); White, Neil H. [Washington University in St. Louis, Department of Pediatrics, St. Louis, MO (United States); Tsalikian, Eva [University of Iowa, Pediatric Endocrinology, Iowa City, IA (United States); Reiss, Allan L. [Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford, CA (United States); Stanford University, Department of Pediatrics, Stanford, CA (United States); Stanford University, Department of Radiology, Diabetes Research in Children Network (DirecNet), Stanford, CA (United States); Collaboration: on behalf of the Diabetes Research in Children Network (DirecNet)

    2014-02-15

    The ability to lie still in an MRI scanner is essential for obtaining usable image data. To reduce motion, young children are often sedated, adding significant cost and risk. We assessed the feasibility of using a simple and affordable behavioral desensitization program to yield high-quality brain MRI scans in sedation-free children. 222 children (4-9.9 years), 147 with type 1 diabetes and 75 age-matched non-diabetic controls, participated in a multi-site study focused on effects of type 1 diabetes on the developing brain. T1-weighted and diffusion-weighted imaging (DWI) MRI scans were performed. All children underwent behavioral training and practice MRI sessions using either a commercial MRI simulator or an inexpensive mock scanner consisting of a toy tunnel, vibrating mat, and video player to simulate the sounds and feel of the MRI scanner. 205 children (92.3%), mean age 7 ± 1.7 years had high-quality T1-W scans and 174 (78.4%) had high-quality diffusion-weighted scans after the first scan session. With a second scan session, success rates were 100% and 92.5% for T1-and diffusion-weighted scans, respectively. Success rates did not differ between children with type 1 diabetes and children without diabetes, or between centers using a commercial MRI scan simulator and those using the inexpensive mock scanner. Behavioral training can lead to a high success rate for obtaining high-quality T1-and diffusion-weighted brain images from a young population without sedation. (orig.)

  17. Kinematically Coupled Strike-Slip and Normal Faults in the Lake Mead Strike-Slip Fault System, Southeast Nevada

    Science.gov (United States)

    Kattenhorn, S. A.; Marshall, S. T.; Cooke, M. L.

    2008-12-01

    The Lake Mead fault system consists of a ~95 km long, northeast-trending zone of strike-slip faults of Miocene age that accommodate a total left-lateral offset of 20-65 km. We use a combination of detailed field mapping and numerical modeling to show that a previously unnamed left-lateral strike-slip segment of the Lake Mead fault system and a dense cluster of dominantly west-dipping normal faults acted in concert to accommodate regional left-lateral offset. We suggest that the strike-slip fault that we refer to as the Pinto Ridge fault: (1) was kinematically related to other faults of the Lake Mead fault system; (2) was responsible for the creation of the normal fault cluster at Pinto Ridge; and (3) utilized these normal faults as linking structures between separate strike-slip fault segments to create a longer, through-going fault. Results from numerical models demonstrate that the observed location and curving strike patterns of the normal fault cluster is consistent with the faults having formed as secondary structures as the result of the perturbed stress field around the slipping Pinto Ridge fault. Comparison of mechanical efficiency of various normal fault geometries within extending terranes suggests that the observed west dip of normal faults reflects a west- dipping anisotropy at depth, such as a detachment. The apparent terminations of numerous strike-slip faults of the Lake Mead fault system into west-dipping normal faults suggest that a west-dipping detachment may be regionally coherent.

  18. Bilateral unstable slipped capital femoral epiphysis: a look at risk factors.

    Science.gov (United States)

    Herrera-Soto, José A; Vanderhave, Kelly L; Gordon, Eric; Fabregas, Jorge; Phillips, Jonathan H; Schoenecker, Perry; Parsch, Klaus

    2011-06-14

    Unstable slipped capital femoral epiphysis can have disastrous complications including osteonecrosis and chondrolysis. It has been shown that 20% to 80% of patients may develop a contralateral slip ≤18 months after diagnosis. The purpose of this article is to report and characterize patients who developed bilateral unstable slips. After Institutional Review Board approval, the patients included were only those with bilateral unstable slipped capital femoral epiphyses. A minimum 2-year follow-up was required. Seven patients, all female, were included in the study, with an average age of 11.4 years at the time of their first slips. The interval between slips averaged 127 days (range, 0-245 days). All but 1 patient presented with a severe slip. The second slip was also severe in 3 patients and less severe in 4 patients. The triradiate cartilage was open in 3 patients. Two patients required corrective osteotomies. Chondrolysis developed in 2 patients with no osteonecrosis reported. The incidence of bilateral unstable slips ranged from 4% to 20% of all unstable slipped capital femoral epiphyses based on our findings. Skeletal immaturity was not a risk factor. The surgeon must be vigilant for the possibility of bilateral slips. The family must be instructed on precautions patients must take while recuperating from unstable slipped capital femoral epiphyses. Contralateral fixation of the unaffected side may be warranted in patients with initial severe unstable slipped capital femoral epiphyses to prevent this condition. Copyright 2011, SLACK Incorporated.

  19. Experimental modelling of tectonics-erosion-sedimentation interactions in compressional, extensional, and strike-slip settings

    Science.gov (United States)

    Graveleau, Fabien; Strak, Vincent; Dominguez, Stéphane; Malavieille, Jacques; Chatton, Marina; Manighetti, Isabelle; Petit, Carole

    2015-09-01

    Tectonically controlled landforms develop morphologic features that provide useful markers to investigate crustal deformation and relief growth dynamics. In this paper, we present results of morphotectonic experiments obtained with an innovative approach combining tectonic and surface processes (erosion, transport, and sedimentation), coupled with accurate model monitoring techniques. This approach allows for a qualitative and quantitative analysis of landscape evolution in response to active deformation in the three end-member geological settings: compression, extension, and strike-slip. Experimental results outline first that experimental morphologies evolve significantly at a short time scale. Numerous morphologic markers form continuously, but their lifetime is generally short because erosion and sedimentation processes tend to destroy or bury them. For the compressional setting, the formation of terraces above an active thrust appears mainly controlled by narrowing and incision of the main channel through the uplifting hanging-wall and by avulsion of deposits on fan-like bodies. Terrace formation is irregular even under steady tectonic rates and erosional conditions. Terrace deformation analysis allows retrieving the growth history of the structure and the fault slip rate evolution. For the extensional setting, the dynamics of hanging-wall sedimentary filling appears to control the position of the base level, which in turn controls footwall erosion. Two phases of relief evolution can be evidenced: the first is a phase of relief growth, and the second is a phase of upstream propagation of topographic equilibrium that is reached first in the sedimentary basin. During the phase of relief growth, the formation of triangular facets occurs by degradation of the fault scarp, and their geometry (height) becomes stationary during the phase of upstream propagation of the topographic equilibrium. For the strike-slip setting, the complex morphology of the wrench zone

  20. Caught in the Net: Perineuronal Nets and Addiction

    Directory of Open Access Journals (Sweden)

    Megan Slaker

    2016-01-01

    Full Text Available Exposure to drugs of abuse induces plasticity in the brain and creates persistent drug-related memories. These changes in plasticity and persistent drug memories are believed to produce aberrant motivation and reinforcement contributing to addiction. Most studies have explored the effect drugs of abuse have on pre- and postsynaptic cells and astrocytes; however, more recently, attention has shifted to explore the effect these drugs have on the extracellular matrix (ECM. Within the ECM are unique structures arranged in a net-like manner, surrounding a subset of neurons called perineuronal nets (PNNs. This review focuses on drug-induced changes in PNNs, the molecules that regulate PNNs, and the expression of PNNs within brain circuitry mediating motivation, reward, and reinforcement as it pertains to addiction.

  1. Waterscape determinants of net mercury methylation in a tropical wetland.

    Science.gov (United States)

    Lázaro, Wilkinson L; Díez, Sergi; da Silva, Carolina J; Ignácio, Áurea R A; Guimarães, Jean R D

    2016-10-01

    The periphyton associated with freshwater macrophyte roots is the main site of Hg methylation in different wetland environments in the world. The aim of this study was to test the use of connectivity metrics of water bodies, in the context of patches, in a tropical waterscape wetland (Guapore River, Amazonia, Brazil) as a predictor of potential net methylmercury (MeHg) production by periphyton communities. We sampled 15 lakes with different patterns of lateral connectivity with the main river channel, performing net mercury methylation potential tests in incubations with local water and Eichhornia crassipes root-periphyton samples, using (203)HgCl2 as a tracer. Physico-chemical variables, landscape data (morphological characteristics, land use, and lateral connection type of water bodies) using GIS resources and field data were analyzed with Generalized Additive Models (GAM). The net Me(203)Hg production (as % of total added (203)Hg) was expressive (6.2-25.6%) showing that periphyton is an important matrix in MeHg production. The model that best explained the variation in the net Me(203)Hg production (76%) was built by the variables: connection type, total phosphorus and dissolved organic carbon (DOC) in water (AICc=48.324, p=0.001). Connection type factor was the best factor to model fit (r(2)=0.32; p=0.008) and temporarily connected lakes had higher rates of net mercury methylation. Both DOC and total phosphorus showed positive significant covariation with the net methylation rates (r(2)=0.26; p=0.008 and r(2)=0.21; p=0.012 respectively). Our study suggests a strong relationship between rates of net MeHg production in this tropical area and the type of water body and its hydrological connectivity within the waterscape. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Army Net Zero Prove Out. Army Net Zero Training Report

    Science.gov (United States)

    2014-11-20

    sensors were strategically placed throughout the installation by magnetically attaching them to water main valve stems. The sensors check sound...Recycle Wrap  Substitutes for Packaging Materials  Re-Use of Textiles and Linens  Setting Printers to Double-Sided Printing Net Zero Waste...can effectively achieve source reduction. Clean and Re-Use Shop Rags - Shop rags represent a large textile waste stream at many installations. As a

  3. Army Net Zero Prove Out. Net Zero Waste Best Practices

    Science.gov (United States)

    2014-11-20

    Anaerobic Digesters – Although anaerobic digestion is not a new technology and has been used on a large-scale basis in wastewater treatment , the...technology and has been used on a large-scale basis in wastewater treatment , the use of the technology should be demonstrated with other...approaches can be used for cardboard and cellulose -based packaging materials. This approach is in line with the Net Zero Waste hierarchy in terms of

  4. A temperature dependent slip factor based thermal model for friction ...

    Indian Academy of Sciences (India)

    This paper proposes a new slip factor based three-dimensional thermal model to predict the temperature distribution during friction stir welding of 304L stainless steel plates. The proposed model employs temperature and radius dependent heat source to study the thermal cycle, temperature distribution, power required, the ...

  5. A temperature dependent slip factor based thermal model for friction ...

    Indian Academy of Sciences (India)

    Abstract. This paper proposes a new slip factor based three-dimensional thermal model to predict the temperature distribution during friction stir welding of 304L stainless steel plates. The proposed model employs temperature and radius dependent heat source to study the thermal cycle, temperature distribution, power ...

  6. The No-Slip Boundary Condition in Fluid Mechanics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 4. The No-Slip Boundary Condition in Fluid Mechanics - 1.The Riddle of Fluid Sticking to the Wall in Flow. Sandeep Prabhakara M D Deshpande. General Article Volume 9 Issue 4 April 2004 pp 50-60 ...

  7. The No-Slip Boundary Condition in Fluid Mechanics

    Indian Academy of Sciences (India)

    A moving fluid in contact with a solid body cannot have velocity relative to the body. Even though the question whether there is slip has been satisfactorily resolved now, it was a difficult and controversial problem. In the first part of this article several basic ideas and details related to this problem are discussed.

  8. Evaluation of slips of white yam ( Dioscorea rotundata poir ...

    African Journals Online (AJOL)

    Landrace Hembamkwase had the longest vine (163.3cm), followed by hybrid TDr 89/02665 while Ame produced the shortest vine. Hembamkwase also out-yielded other genotypes except Ame in 2011 and Nwopoko in 2012. Generally, slips of the hybrid varieties, especially TDr 89/02665 and TDr 97/19177 performed ...

  9. Numerical Simulation of Methane Slip in Dual Fuel Marine Engines

    DEFF Research Database (Denmark)

    Han, Jaehyun; Jensen, Michael Vincent; Pang, Kar Mun

    2017-01-01

    and the valve timings on the methane slip was investigated. MAN L28/32DF engine was modeled to simulate the gas exchange process of the four stroke NG-diesel dual fuel engines. The mesh size of the model was decided based on the sensitivity study on the peak pressure of the cylinder and the fuel mass...

  10. Slip, Swim, Mix, Pack: Fluid Mechanics at the Micron Scale

    Science.gov (United States)

    Lauga, Eric

    2006-11-01

    This talk summarizes my thesis work which was advised by Michael P. Brenner and Howard A. Stone at Harvard University and is devoted to fluid behavior at the micrometer length scale. We consider four different problems. We first address the topic of the no-slip boundary condition in Newtonian liquids. After briefly reviewing the field, we (1) present models for apparent slip in three distinct experimental settings, (2) propose a new method to probe slip and (3) show that slip has virtually no influence on the non-modal stability of shear flows. The second problem we consider addresses mixing in micro-devices. We show that microchannels which are obtained with a single step of microfabrication (that is, have constant height) are able to generate fully three-dimensional flows. The third problem we present proposes a mechanical model for the motion of the bacterium E. coli near solid boundaries. It has been observed that, near a solid surface, E. coli does not swim in a straight line but in clockwise circles, which we show is a consequence of the hydrodynamic interactions between the free- swimming bacterium and the surface. The final problem we consider addresses self-assembly of micro- particles. We show that when spherical particles located on a liquid droplet are forced to come together by evaporation of the droplet, the geometrical and mechanical constraints arising during the process lead to unique final clusters.

  11. Analysing earthquake slip models with the spatial prediction comparison test

    KAUST Repository

    Zhang, L.

    2014-11-10

    Earthquake rupture models inferred from inversions of geophysical and/or geodetic data exhibit remarkable variability due to uncertainties in modelling assumptions, the use of different inversion algorithms, or variations in data selection and data processing. A robust statistical comparison of different rupture models obtained for a single earthquake is needed to quantify the intra-event variability, both for benchmark exercises and for real earthquakes. The same approach may be useful to characterize (dis-)similarities in events that are typically grouped into a common class of events (e.g. moderate-size crustal strike-slip earthquakes or tsunamigenic large subduction earthquakes). For this purpose, we examine the performance of the spatial prediction comparison test (SPCT), a statistical test developed to compare spatial (random) fields by means of a chosen loss function that describes an error relation between a 2-D field (‘model’) and a reference model. We implement and calibrate the SPCT approach for a suite of synthetic 2-D slip distributions, generated as spatial random fields with various characteristics, and then apply the method to results of a benchmark inversion exercise with known solution. We find the SPCT to be sensitive to different spatial correlations lengths, and different heterogeneity levels of the slip distributions. The SPCT approach proves to be a simple and effective tool for ranking the slip models with respect to a reference model.

  12. Discrete dislocation plasticity analysis of single slip tension

    NARCIS (Netherlands)

    Deshpande, VS; Needleman, A; Van der Giessen, E

    2005-01-01

    The effect of loading conditions on the tensile stress versus strain response of micron-sized planar crystals with a single active slip system is investigated via finite and small deformation discrete dislocation plasticity analyses. When rotation of the tensile axis is prevented, lattice curvature

  13. Third Party Fraud inducing Material Mistake Slip Knot Investments ...

    African Journals Online (AJOL)

    In Slip Knot Investments v Du Toit 2011 4 SA 72 (SCA) the Supreme Court of Appeal had to determine if the material mistake of a contractual party induced by the fraud of an independent third party could sustain a plea of iustus error raised by the mistaken party. The position prior to this decision was uncertain and ...

  14. Analysis of slip flow heat transfer between two unsymmetrically ...

    Indian Academy of Sciences (India)

    This paper presents an analytical investigation to study the heat transfer and fluid flow characteristics in the slip flow region for hydrodynamically and thermally fully developed flow between parallel plates.Both upper and lower plates are subjected to asymmetric heat flux boundary conditions. The effect of first ordervelocity ...

  15. The No-Slip Boundary Condition in Fluid Mechanics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 5. The No-Slip Boundary Condition in Fluid Mechanics - Solution of the Sticky Problem. Sandeep Prabhakara M D Deshpande. General Article Volume 9 Issue 5 May 2004 pp 61-71 ...

  16. The Influence of Slip Boundary Condition on Casson Nanofluid Flow over a Stretching Sheet in the Presence of Viscous Dissipation and Chemical Reaction

    Directory of Open Access Journals (Sweden)

    Ahmed A. Afify

    2017-01-01

    Full Text Available The impacts of multiple slips with viscous dissipation on the boundary layer flow and heat transfer of a non-Newtonian nanofluid over a stretching surface have been investigated numerically. The Casson fluid model is applied to characterize the non-Newtonian fluid behavior. Physical mechanisms responsible for Brownian motion and thermophoresis with chemical reaction are accounted for in the model. The governing nonlinear boundary layer equations through appropriate transformations are reduced into a set of nonlinear ordinary differential equations, which are solved numerically using a shooting method with fourth-order Runge-Kutta integration scheme. Comparisons of the numerical method with the existing results in the literature are made and an excellent agreement is obtained. The heat transfer rate is enhanced with generative chemical reaction and concentration slip parameter, whereas the reverse trend is observed with destructive chemical reaction and thermal slip parameter. It is also noticed that the mass transfer rate is boosted with destructive chemical reaction and thermal slip parameter. Further, the opposite influence is found with generative chemical reaction and concentration slip parameter.

  17. A new formulation for minimum input volt-ampere (VA-slip relationship of three-phase induction motors

    Directory of Open Access Journals (Sweden)

    Haroon Ashfaq

    2017-07-01

    Full Text Available The magnetization component of input current of low-rating three-phase induction motor is large which results in poor power factor particularly at low-load conditions. The situation becomes critical when motor is fed from a distributed generating (DG system. In this paper, the performance analysis of induction motor is carried out for minimum input VA. A distinct novel slip is found at which the input VA is minimum independent of the load conditions. This optimum slip is expressed in terms of motor per-phase equivalent circuit parameters. This novel relationship is valid for every induction motor. As compared to rated conditions, a drastic reduction in VA with a large improvement in power factor is observed. Although, a marginal change in output power and efficiency is recorded. All the analytical, simulated and experimental results match each other with a very fair degree of accuracy.

  18. Slip estimation methods for proprioceptive terrain classification using tracked mobile robots

    CSIR Research Space (South Africa)

    Masha, Ditebogo F

    2017-11-01

    Full Text Available Recent work has shown that proprioceptive measurements such as terrain slip can be used for terrain classification. This paper investigates the suitability of four simple slip estimation methods for differentiating between indoor and outdoor terrain...

  19. Investigation into slipping and falling accidents and materials handling in the South African mining industry.

    CSIR Research Space (South Africa)

    Schutte, PC

    2003-03-01

    Full Text Available The objective of this study was to analyze information on slipping and falling accidents and materials handling activities in the South African mining industry. Accident data pertaining to slipping, falling and materials handling accidents...

  20. Airborne Antenna System for Minimum-Cycle-Slip GPS Reception

    Science.gov (United States)

    Wright, C. Wayne

    2009-01-01

    A system that includes a Global Positioning System (GPS) antenna and associated apparatus for keeping the antenna aimed upward has been developed for use aboard a remote-sensing-survey airplane. The purpose served by the system is to enable minimum- cycle-slip reception of GPS signals used in precise computation of the trajectory of the airplane, without having to restrict the airplane to maneuvers that increase the flight time needed to perform a survey. Cycle slip signifies loss of continuous track of the phase of a signal. Minimum-cycle-slip reception is desirable because maintaining constant track of the phase of the carrier signal from each available GPS satellite is necessary for surveying to centimeter or subcentimeter precision. Even a loss of signal for as short a time as a nanosecond can cause cycle slip. Cycle slips degrade the quality and precision of survey data acquired during a flight. The two principal causes of cycle slip are weakness of sig