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1

Avoiding leakage flow-induced vibration by a tube-in-tube slip joint  

SciTech Connect

Parameters and operating conditions (a stability map) were determined for which a specific slip-joint design did not cause self-excited lateral vibration of the two cantilevered, telescoping tubes forming the joint. The joint design featured a localized annular constriction. Flowrate, modal damping, tube engagement length, and eccentric positioning were among the parameters tested. Interestingly, all self-excited vibrations could be avoided by following a simple design rule: place constrictions only at the downstream end of the annular region between the tubes. Also, overall modal damping decreased with increased flowrate, at least initially, for upstream constrictions while the damping increased for downstream constrictions.

Mulcahy, T.M.

1985-01-01

2

Avoiding leakage flow-induced vibration by a tube-in-tube slip joint  

SciTech Connect

Parameters and operating conditions (a stability map) were determined for which a specific slip-joint design did not cause self-excited lateral vibration of the two cantilevered, telescoping tubes forming the joint. The joint design featured a localized annular constriction. Flowrate, modal damping, tube engagement length, and eccentric positioning were among the parameters tested. Interestingly, all self-excited vibrations could be avoided by following a simple design rule: place constrictions only at the downstream end of the annular region between the tubes. Also, overall modal damping decreased with increased flowrate, at least initially, for upstream constrictions while the damping increased for downstream constrictions.

Mulcahy, T.M.

1984-10-01

3

Stick-slip friction and wear of articular joints  

PubMed Central

Stick-slip friction was observed in articular cartilage under certain loading and sliding conditions and systematically studied. Using the Surface Forces Apparatus, we show that stick-slip friction can induce permanent morphological changes (a change in the roughness indicative of wear/damage) in cartilage surfaces, even under mild loading and sliding conditions. The different load and speed regimes can be represented by friction maps—separating regimes of smooth and stick-slip sliding; damage generally occurs within the stick-slip regimes. Prolonged exposure of cartilage surfaces to stick-slip sliding resulted in a significant increase of surface roughness, indicative of severe morphological changes of the cartilage superficial zone. To further investigate the factors that are conducive to stick-slip and wear, we selectively digested essential components of cartilage: type II collagen, hyaluronic acid (HA), and glycosaminoglycans (GAGs). Compared with the normal cartilage, HA and GAG digestions modified the stick-slip behavior and increased surface roughness (wear) during sliding, whereas collagen digestion decreased the surface roughness. Importantly, friction forces increased up to 2, 10, and 5 times after HA, GAGs, and collagen digestion, respectively. Also, each digestion altered the friction map in different ways. Our results show that (i) wear is not directly related to the friction coefficient but (ii) more directly related to stick-slip sliding, even when present at small amplitudes, and that (iii) the different molecular components of joints work synergistically to prevent wear. Our results also suggest potential noninvasive diagnostic tools for sensing stick-slip in joints. PMID:23359687

Lee, Dong Woog; Banquy, Xavier; Israelachvili, Jacob N.

2013-01-01

4

PROGRESS IN PROCESS INTENSIFICATION: SYNTHESIS OF IMIDAZOLE DERIVATIVES USING A SPINNING TUBE-IN-TUBE REACTOR  

EPA Science Inventory

The high purity, high throughput synthesis of a number of imidazole derivatives using a spinning tube-in-tube reactor (STT®, Kreido Laboratories, Camarillo California) has been carried out. The STT® reactor allows the high throughput production of high purity imidazole derivativ...

5

Performance of multi tubes in tube helically coiled as a compact heat exchanger  

NASA Astrophysics Data System (ADS)

Multi tubes in tube helically coiled heat exchanger is proposed as a compact heat exchanger. Effects of heat exchanger geometric parameters and fluid flow parameters; namely number of inner tubes, annulus hydraulic diameter, Reynolds numbers and input heat flux, on performance of the heat exchanger are experimentally investigated. Different coils with different numbers of inner tubes, namely 1, 3, 4 and 5 tubes, were tested. Results showed that coils with 3 inner tubes have higher values of heat transfer coefficient and compactness parameter (bar{h} Ah ). Pressure drop increases with increasing both of Reynolds number and number of inner tubes. Correlations of average Nusselt number were deduced from experimental data in terms of Reynolds number, Prandtl number, Number of inner coils tubes and coil hydraulic diameter. Correlations prediction was compared with experimental data and the comparison was fair enough.

Nada, S. A.; El Shaer, W. G.; Huzayyin, A. S.

2014-12-01

6

Inference of coseismic slip via joint inversion of GPS and aftershock data: The 2004 Parkfield example  

NASA Astrophysics Data System (ADS)

In many coseismic slip inversions, the number of model parameters is much larger than that of the independent observations, and the problem is extremely underdetermined. It is thus instructive to incorporate additional data sets into the slip inversion. In this study I describe a new approach for coseismic slip inversion, whereby both GPS displacements and first day aftershock rate changes are used jointly to constrain the solution. The joint inversion incorporates the Dieterich's aftershock model, which adopts a constitutive friction that depends logarithmically on the sliding rate. The method is applied to the 2004 Parkfield earthquake. The joint inversion not only provides resolving power of slip at depths inaccessible to GPS-only inversions, but it also helps to gain insight on the fault mechanical properties. I show that the data are consistent with the adopted aftershock model being the dominant mechanism for aftershock production along the Parkfield segment, and I obtain an upper bound on the friction dependence on the log of rate of fault patches that have experienced aftershock activity. A consequence of the irregular aftershock distribution is that the slip distribution is extremely nonsmooth, with the aftershock zones acting as barriers.

Ziv, A.

2012-03-01

7

COMMODITY SCALE SYNTHESIS OF 1-METHYLIMIDAZOLE BASED IONIC LIQUIDS USING A SPINNING TUBE-IN-TUBE REACTOR  

EPA Science Inventory

The continuous large-scale preparation of several 1-methylimidazole based ionic liquids was carried out using a Spinning Tube-in-Tube (STT) reactor (manufactured by Kreido Laboratories). This reactor, which embodies and facilitates the use of Green Chemistry principles and Proce...

8

Flow Chemistry: Intelligent Processing of Gas-Liquid Transformations Using a Tube-in-Tube Reactor.  

PubMed

Conspectus The previous decade has witnessed the expeditious uptake of flow chemistry techniques in modern synthesis laboratories, and flow-based chemistry is poised to significantly impact our approach to chemical preparation. The advantages of moving from classical batch synthesis to flow mode, in order to address the limitations of traditional approaches, particularly within the context of organic synthesis are now well established. Flow chemistry methodology has led to measurable improvements in safety and reduced energy consumption and has enabled the expansion of available reaction conditions. Contributions from our own laboratories have focused on the establishment of flow chemistry methods to address challenges associated with the assembly of complex targets through the development of multistep methods employing supported reagents and in-line monitoring of reaction intermediates to ensure the delivery of high quality target compounds. Recently, flow chemistry approaches have addressed the challenges associated with reactions utilizing reactive gases in classical batch synthesis. The small volumes of microreactors ameliorate the hazards of high-pressure gas reactions and enable improved mixing with the liquid phase. Established strategies for gas-liquid reactions in flow have relied on plug-flow (or segmented flow) regimes in which the gas plugs are introduced to a liquid stream and dissolution of gas relies on interfacial contact of the gas bubble with the liquid phase. This approach confers limited control over gas concentration within the liquid phase and is unsuitable for multistep methods requiring heterogeneous catalysis or solid supported reagents. We have identified the use of a gas-permeable fluoropolymer, Teflon AF-2400, as a simple method of achieving efficient gas-liquid contact to afford homogeneous solutions of reactive gases in flow. The membrane permits the transport of a wide range of gases with significant control of the stoichiometry of reactive gas in a given reaction mixture. We have developed a tube-in-tube reactor device consisting of a pair of concentric capillaries in which pressurized gas permeates through an inner Teflon AF-2400 tube and reacts with dissolved substrate within a liquid phase that flows within a second gas impermeable tube. This Account examines our efforts toward the development of a simple, unified methodology for the processing of gaseous reagents in flow by way of development of a tube-in-tube reactor device and applications to key C-C, C-N, and C-O bond forming and hydrogenation reactions. We further describe the application to multistep reactions using solid-supported reagents and extend the technology to processes utilizing multiple gas reagents. A key feature of our work is the development of computer-aided imaging techniques to allow automated in-line monitoring of gas concentration and stoichiometry in real time. We anticipate that this Account will illustrate the convenience and benefits of membrane tube-in-tube reactor technology to improve and concomitantly broaden the scope of gas/liquid/solid reactions in organic synthesis. PMID:25611216

Brzozowski, Martin; O'Brien, Matthew; Ley, Steven V; Polyzos, Anastasios

2015-02-17

9

Numerical studies of an eccentric tube-in-tube helically coiled heat exchanger for IHEP-ADS helium purification system  

E-print Network

The tube-in-tube helically coiled (TTHC) heat exchanger is preferred in the purifier of IHEP-ADS helium purification system. The position of an internal tube is usually eccentric in a TTHC heat exchanger in practice, while most TTHC heat exchangers in the literature studied are concentric. In this paper, TTHC heat exchangers with different eccentricity ratios are numerically studied for turbulent flow and heat transfer characteristics under different flow rates. The fluid considered is helium at the pressure of 20Mpa, with temperature dependent thermo-physical properties for the inner tube and the annulus. The inner Nusselt number between the concentric and eccentric TTHC heat exchangers are compared, so is the annulus Nusselt number. The results show that with the eccentricity increasing, the annulus Nusselt number increases substantially. According to the numerical data, new empirical correlations of Nusselt number as a function of Reynolds number and eccentricity for the inner tube and the annulus are pres...

Zhang, Jianqin

2014-01-01

10

IN-SITU MONITORING OF PRODUCT STREAMS FROM A SPINNING TUBE-IN-TUBE REACTOR USING A METTLER-TOLEDO REACT-IR  

EPA Science Inventory

A Mettler-Toledo ReactIR system has been used for in-line, real-time monitoring of the product stream from a spinning tube-in-tube reactor (STT®, Kreido Laboratories, Camarillo California). This combination of a process intensified continuous-flow reactor and an in-situ analytic...

11

Joint coseismic and postseismic kinematic slip inversions in a Bayesian framework (Invited)  

Microsoft Academic Search

The classic linear, kinematic, static slip inversion of geodetic data requires specification of a smoothing norm of slip parameters, a residual norm of the data, and a choice about the relative weight between the two norms and the relative weights of multiple data sets. Inversions for unknown fault geometry are nonlinear and therefore the fault geometry is often assumed to

K. M. Johnson; J. Fukuda; J. Sun

2010-01-01

12

Slip distribution of the 2003 Tokachi-oki Mw 8.1 earthquake from joint inversion of tsunami waveforms and geodetic data  

Microsoft Academic Search

We study the 2003 Mw 8.1 Tokachi-oki earthquake, a great interplate event that occurred along the southwestern Kuril Trench and generated a significant tsunami. To determine the earthquake slip distribution, we perform the first joint inversion of tsunami waveforms measured by tide gauges and of coseismic displacement measured both by GPS stations and three ocean bottom pressure gauges (PG) for

F. Romano; A. Piatanesi; S. Lorito; K. Hirata

2010-01-01

13

Second free radial forearm flap for urethral reconstruction after partial flap necrosis of tube-in-tube phalloplasty with radial forearm flap: a report of two cases.  

PubMed

We present a salvage procedure to reconstruct the neo-urethra after partial flap necrosis occurring in free radial forearm flap (RFF) phalloplasty for sex reassignment surgery. Two cases of tube-in-tube phalloplasty using a free sensate RFF are described in which partial flap necrosis occurred involving the complete length of the neo-urethra and a strip of the outer lining of the neo-phallus. Neo-urethra-reconstruction was performed with a second RFF from the contralateral side providing well-vascularized tissue. No flap-related complications were observed. Twelve months postoperatively, both patients were able to void while standing. A satisfactory aesthetic appearance of the neo-phallus could be preserved with an excellent tactile and erogenous sensitivity. Using this technique, we successfully salvaged the neo-urethra and reconstructed the outer lining of the neo-phallus PMID:24038531

Tchang, Laurent A H; Largo, René D; Babst, Doris; Wettstein, Reto; Haug, Martin D; Kalbermatten, Daniel F; Schaefer, Dirk J

2014-01-01

14

Experimental investigation of the dynamic installation of a slip joint connection between the monopile and tower of an offshore wind turbine  

NASA Astrophysics Data System (ADS)

The failure of the traditional grouted connections of offshore wind turbines has led to the investigation of alternatives that provide a connection between the foundation pile and the turbine tower. An alternative to the traditional joint is a steel-to-steel connection also called a slip joint. To ensure a proper fit of the slip joint a dynamic installation of the joint is proposed. In this contribution, the effectiveness of harmonic excitation as an installation procedure is experimentally investigated using a 1:10 scaled model of the joint. During the dynamic installation test the applied static load, settlements and dynamic response of the joint are monitored using respectively load cells, taut wires and strain gauges placed both inside and outside the conical surfaces. The results show that settlement occurs only when applying a harmonic load at specific forcing frequencies. The settlement stabilizes to a certain level for each of the specific frequencies, indicating that a controlled way of installation is possible. The results show that it is essential to vibrate at specific frequencies and that a larger amplitude of the harmonic force does not automatically lead to additional settlement.

Segeren, M. L. A.; Hermans, K. W.

2014-06-01

15

Coseismic Fault Slip Rupture from the Joint Inversion of Teleseismic, Local Strong-Motion and CGPS Related to the 2010 Jia-Shian Earthquake in Southwestern Taiwan  

NASA Astrophysics Data System (ADS)

The Jia-Shian earthquake (Mw=6.3) occurred on 04th March 2010 in the southwestern Taiwan. We used the waveforms of teleseismics to identify the strike, dip and rake of focal mechanism are 311/33/37. Furthermore, we explored the strike, dip and rake are 316/40/44 on the first pulse of the teleseismic P wave. We also took account of the Continuous Global Positioning System (CGPS) data for the coseismic offset. The maximum horizontal and vertical (uplift) of coseismic offsets at the surface are 29.8mm± 1.0mm and 30.6mm± 5.1mm, respectively at station GS51. Moreover, the space and time distribution of slip during the coseismic rupture was modeled by the joint inversion, which includes the CGPS coseismic offset, the teleseismic, and near field seismic records. We identified the faults geometry and reconstructed the rupture process of coseismic faults slip. The initial rupture was generated on the northwest - southeast trending fault and propagated to the northeast - southwest trending structure after 5 s of main shock. Their strike, dip and rake are 311/33/37 and 020/25/108, respectively. The average slip of rupture was 20.1 cm, with the maximum slip of 50.4 cm. The rupture of the seismic moment was 4.0 × 10 ^ 25 dyne-cm in 30 s of duration time.The slip rupture constrained the synthetic data quite well, especially for the CGPS coseismic offset. We inferred the Jia-Shian earthquake took place on blind fault and the northeast - southwest trending structure was activated following the rupture on main northwest - southeast trending fault.

Lin, Kuan-Chuan; Delouis, Bertrand; Hu, Jyr-Ching; Nocquet, Jean-Mathieu; Mozziconacci, Laetitia; Bethoux, Nicole

2013-04-01

16

Inference of Co-Seismic Slip Distribution Via a Joint Inversion of GPS and Aftershock Data Sets: The 2004 Parkfield Example  

NASA Astrophysics Data System (ADS)

Since the advent of space geodesy in the late eighties, ground motion data are being commonly used to infer co-seismic slip distributions. The prime objective of these studies is to identify barriers and/or asperities along the rupture plane. This, in turn, may shed light on the rupture physics and help to discriminate between different models. A serious problem when utilizing geodetic data to infer co-seismic slip distribution is the rapid drop of the resolving power with depth. I will show that use of high quality relocated aftershock data together with aftershock constitutive laws can alleviate this problem. I choose the 2004 Parkfield earthquake as a case study, because its rupture geometry is well constrained and since high quality earthquake catalog is available. Furthermore, the available InSAR data for that earthquake is problematic, as it includes significant contributions from the San Simeon 2003 post-seismic relaxation, as well as (at least) two days of Parkfield’s post-seismic relaxation. I will describe how the 2004 Parkfield co-seismic slip distribution can be inferred via joint inversion of GPS and aftershock data sets. I will show that good fit to both data sets can only be obtained for a constitutive friction parameter that is two to three orders of magnitude smaller than the laboratory values. Finally, I will discuss the implications for fault friction and aftershock physics.

Ziv, A.

2010-12-01

17

Localized fault slip to the trench in the 2010 Maule, Chile Mw = 8.8 earthquake from joint inversion of high-rate GPS, teleseismic body waves, InSAR, campaign GPS, and tsunami observations  

NASA Astrophysics Data System (ADS)

27 February 2010, Mw 8.8 Maule earthquake ruptured ~500 km along the plate boundary offshore central Chile between 34°S and 38.5°S. Establishing whether coseismic fault offset extended to the trench is important for interpreting both shallow frictional behavior and potential for tsunami earthquakes in the region. Joint inversion of high-rate GPS, teleseismic body waves, interferometric synthetic aperture radar (InSAR), campaign GPS, and tsunami observations yields a kinematic rupture model with improved resolution of slip near the trench. Bilateral rupture expansion is resolved in our model with relatively uniform slip of 5-10 m downdip beneath the coast and two near-trench high-slip patches with >12 m displacements. The peak slip is ~17 m at a depth of ~15 km on the central megathrust, located ~200 km north from the hypocenter and overlapping the rupture zone of the 1928 M ~8 event. The updip slip is ~16 m near the trench. Another shallow near-trench patch is located ~150 km southwest of the hypocenter, with a peak slip of 12 m. Checkerboard resolution tests demonstrate that correctly modeled tsunami data are critical to resolution of slip near the trench, with other data sets allowing, but not requiring slip far offshore. Large interplate aftershocks have a complementary distribution to the coseismic slip pattern, filling in gaps or outlining edges of large-slip zones. Two clusters of normal faulting events locate seaward along the plate motion direction from the localized regions of large near-trench slip, suggesting that proximity of slip to the trench enhanced extensional faulting in the underthrusting plate.

Yue, Han; Lay, Thorne; Rivera, Luis; An, Chao; Vigny, Christophe; Tong, Xiaopeng; Báez Soto, Juan Carlos

2014-10-01

18

Depth distribution of coseismic slip along the Nankai Trough, Japan, from joint inversion of geodetic and tsunami data  

Microsoft Academic Search

Two large earthquakes, the 1944 Tonankai earthquake and the 1946 Nankaido earthquake, occurred on the Nankai trough, where the Philippine Sea plate is subducting beneath the Eurasian plate. Coseismic crustal movements on land were measured by leveling, while those in ocean were recorded as tsunami waveforms on tide gauges. The coseismic slip distribution inverted from these data shows that the

Kenji Satake

1993-01-01

19

Spatiotemporal model of aseismic slip on the Hayward fault inferred from joint inversion of geodetic and seismic data time series  

NASA Astrophysics Data System (ADS)

Interferometric synthetic aperture radar (InSAR) provides valuable spatiotemporal observations of surface deformation in volcanic and tectonic areas. In this study we generate a long time series of InSAR-measured deformation over the San Francisco Bay Area by combining over 100 ERS1/2 and Envisat SAR acquisitions from 1992 through 2011. We apply an advanced multitemporal processing algorithm that uses multiple-master interferometry and generate about 700 interferograms (ERS-ERS, Envisat-Envisat and ERS-Envisat pairs) with temporal and perpendicular baseline smaller than 4 years and 300 m, respectively. The systematic errors (such as DEM error and atmospheric delay) are estimated and reduced by using a variety of wavelet based filters. The differential displacement measured in each unwrapped interferogram is inverted by using an L1-norm minimization approach to generate time series of the surface displacement for identified stable pixels. Using a Kalman filter, the line-of-sight velocity is estimated, temporal random noise is reduced and the displacement variance-covariance matrix is refined. To solve for the time dependent model of aseismic slip on the Hayward fault, the upper-crustal fault plane is discretized into triangular patches. The size of these patches is optimized in a way that allows estimating the fault slip with maximum precision. Then, we apply an iterated inversion approach, combining static slip inversion and Kalman filtering to model temporal behavior of the slip. For the static inversion we expand the slip to the wavelet base functions and truncate noisy coefficients, which provide a solution equivalent to implementation of the Laplace smoothing operator in conventional slip inversion. This novel approach, however, overcomes the need of choosing a smoothing operator and allows automating the whole inversion step. Since we aim to integrate seismic and creepmeter data sets, the issue of relative weighting of these data sets becomes important, which we address by applying a new statistical method. This method incorporates an iterative algorithm that statistically estimates the true relative weight of different observations. Combination of the advanced InSAR analysis, time dependent modeling and data handling allows us to investigate spatiotemporal variation of the creep at Hayward fault in response to small changes in the regional stress field, for instance, due to a 2007 Mw 4.2 Oakland earthquake.

Shirzaei, M.; Burgmann, R.

2011-12-01

20

Unusual combination of lesions of the traumatic hand: closed central slip laceration of the extensor and interphalangeal thumb joint's dislocation (a case report)  

PubMed Central

From the functional standpoint, the hand is one of the most important organs of the body. However, its significance depends largely upon the pincer action of the thumb-index. The management of traumatic lesions of the hand is nowadays’ subject of numerous scientific discussions. We present here the case of a patient with a recent laceration of the central slip of the extensor tendon with boutonniere deformity linked to a dislocated interphalangeal thumb of the same hand with a loss of force of the clip thumb and index finger. This combination is a rare lesional of the traumatic hand that has not been previously reported in any orthopedic literature. It was observed after adopting the orthopedic treatment that the range of motion of its joint was at the same level as its healthy side without observing any redislocations during the 6-month follow-up period. PMID:25426188

Boussakri, Hassan; Azarkane, Mohamad; Dahmani, Omar; Elidrissi, Mohamad; Shimi, Mohamed; Elibrahimi, Abdelhalim; Elmrini, Abdelmajid

2014-01-01

21

Unusual combination of lesions of the traumatic hand: closed central slip laceration of the extensor and interphalangeal thumb joint's dislocation (a case report).  

PubMed

From the functional standpoint, the hand is one of the most important organs of the body. However, its significance depends largely upon the pincer action of the thumb-index. The management of traumatic lesions of the hand is nowadays' subject of numerous scientific discussions. We present here the case of a patient with a recent laceration of the central slip of the extensor tendon with boutonniere deformity linked to a dislocated interphalangeal thumb of the same hand with a loss of force of the clip thumb and index finger. This combination is a rare lesional of the traumatic hand that has not been previously reported in any orthopedic literature. It was observed after adopting the orthopedic treatment that the range of motion of its joint was at the same level as its healthy side without observing any redislocations during the 6-month follow-up period. PMID:25426188

Boussakri, Hassan; Azarkane, Mohamad; Dahmani, Omar; Elidrissi, Mohamad; Shimi, Mohamed; Elibrahimi, Abdelhalim; Elmrini, Abdelmajid

2014-01-01

22

Joint Determination of Slip and Stress Drop in a Bayesian Inversion Approach: A Case Study for the 2010 M8.8 Maule Earthquake  

NASA Astrophysics Data System (ADS)

Stress drop is a key factor in earthquake mechanics and engineering seismology. However, stress drop calculations based on fault slip can be significantly biased, particularly due to subjectively determined smoothing conditions in the traditional least-square slip inversion. In this study, we introduce a mechanically constrained Bayesian approach to simultaneously invert for fault slip and stress drop based on geodetic measurements. A Gaussian distribution for stress drop is implemented in the inversion as a prior. We have done several synthetic tests to evaluate the stability and reliability of the inversion approach, considering different fault discretization, fault geometries, utilized datasets, and variability of the slip direction, respectively. We finally apply the approach to the 2010 M8.8 Maule earthquake and invert for the coseismic slip and stress drop simultaneously. Two fault geometries from the literature are tested. Our results indicate that the derived slip models based on both fault geometries are similar, showing major slip north of the hypocenter and relatively weak slip in the south, as indicated in the slip models of other studies. The derived mean stress drop is 5-6 MPa, which is close to the stress drop of ~7 MPa that was independently determined according to force balance in this region Luttrell et al. (J Geophys Res, 2011). These findings indicate that stress drop values can be consistently extracted from geodetic data.

Wang, Lifeng; Zöller, Gert; Hainzl, Sebastian

2015-02-01

23

Joint Determination of Slip and Stress Drop in a Bayesian Inversion Approach: A Case Study for the 2010 M8.8 Maule Earthquake  

NASA Astrophysics Data System (ADS)

Stress drop is a key factor in earthquake mechanics and engineering seismology. However, stress drop calculations based on fault slip can be significantly biased, particularly due to subjectively determined smoothing conditions in the traditional least-square slip inversion. In this study, we introduce a mechanically constrained Bayesian approach to simultaneously invert for fault slip and stress drop based on geodetic measurements. A Gaussian distribution for stress drop is implemented in the inversion as a prior. We have done several synthetic tests to evaluate the stability and reliability of the inversion approach, considering different fault discretization, fault geometries, utilized datasets, and variability of the slip direction, respectively. We finally apply the approach to the 2010 M8.8 Maule earthquake and invert for the coseismic slip and stress drop simultaneously. Two fault geometries from the literature are tested. Our results indicate that the derived slip models based on both fault geometries are similar, showing major slip north of the hypocenter and relatively weak slip in the south, as indicated in the slip models of other studies. The derived mean stress drop is 5-6 MPa, which is close to the stress drop of ~7 MPa that was independently determined according to force balance in this region uc(Luttrell) et al. (J Geophys Res, 2011). These findings indicate that stress drop values can be consistently extracted from geodetic data.

Wang, Lifeng; Zöller, Gert; Hainzl, Sebastian

2014-06-01

24

Partitioning Slip  

NSDL National Science Digital Library

This activity consists of four exercises that deal with the partitioning of slip within scenarios involving two or more faults. The first three are hypothetical situations; the last activity focuses on the plate boundary in southern California.

25

Kinematic Coseismic Slip Model for the 12 May 2008 Wenchuan-Beichuan Mw 7.9 Earthquake in Sichuan, China from Joint Inversion of ALOS, Envisat and Teleseismic Data*  

NASA Astrophysics Data System (ADS)

The Mw 7.9 earthquake struck Sichuan province on 12 May 2008 causing catastrophic damage over a large area including the county seats of Wenchuan and Beichuan. We use pixel-offset analysis of amplitude images for ALOS PALSAR and Envisat ASAR coseismic pairs to map the major surface ruptures. The largest amount of displacement (2--8 m of oblique right-lateral slip) occurred along the Beichuan fault and an extension to the north for a total distance of about 215 km. A second major rupture occurred on the Hanwang fault (a section of the Pengguan fault), beneath an anticline in the Sichuan basin about 10 km to the SE of the Beichuan fault, with nearly pure thrust slip. A third short, but intense, rupture strikes NW through the town of Xiaoyudong and transfers slip to another thrust about 5 km SE of the main rupture that ruptured only about 6 km parallel to the Beichuan fault. This small, probably shallow, block moved at least 5 m in the ALOS line of sight. Kinematic slip models for the earthquake have been estimated using a joint inversion of teleseismic data with the six ascending-track PALSAR and three descending-track ASAR strip-map interferograms. The models show that the rupture initiated with a small, 3-second pulse of emergent displacement followed by 15 seconds of moderate moment release with nearly pure thrust motion. More rapid moment release then started about 20 km from the hypocenter at shallower depths near the SW end of the major surface ruptures on the Beichuan fault. Another major patch of slip, coherent with the pixel-offset and InSAR analysis, is identified 130 km away from the epicenter, near the town of Beichuan. While the southern part of the rupture had primarily thrust motion, slip rotated to right-lateral as the rupture propagated the NE. *Part of this research was performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration.

Fielding, E. J.; Sladen, A.; Li, Z.; Ryder, I.; Bürgmann, R.; Avouac, J.

2008-12-01

26

Load history dependence in problems of micro-slip evolution  

Microsoft Academic Search

A region of micro-slip may develop at the interface of two contacting bodies subjected to compression and shear. Prediction of a slip response to the applied system of loads is of great interest in structural dynamics as shear microdisplacements are found to be a source of energy dissipation in jointed elements. Such prediction is challenged by the fact that slip

Hemanth Gopal; Larissa Gorbatikh

2004-01-01

27

Kinematic fault slip model from joint inversion of teleseismic, GPS, InSAR and subpixel-correlation measurements of the 2010 El Mayor-Cucapah earthquake and postseismic deformation (Invited)  

NASA Astrophysics Data System (ADS)

We use interferometric analysis of synthetic aperture radar (SAR) images (InSAR) and pixel tracking by subpixel correlation of SAR and optical images to map the fault ruptures and surface deformation of the 4 April 2010 El Mayor-Cucapah earthquake (Mw 7.2) in Baja California, Mexico. We then combine sampled InSAR and subpixel correlation results with GPS offsets at PBO stations and teleseismic waveforms in a joint inversion to produce a kinematic fault slip model. Pixel-tracking measurements from SPOT 2.5 m panchromatic images and from Envisat ASAR and ALOS PALSAR images measure large ground displacements close to fault ruptures, with a strong discontinuity where the rupture reached the surface. Optical image subpixel correlation measures horizontal displacements in both the east-west and north-south directions and shows the earthquake ruptured the Pescadores Fault in the southern Sierra Cucapah and the Borrego Fault in the central and northern edge of the mountain range. At the south end of the Sierra Cucapah, the fault ruptures fork into two subparallel strands with substantial slip on both visible. SAR image subpixel correlation measures horizontal deformation in the along-track direction of the satellite (approximately north or south) and in the radar line-of-sight direction. SAR along-track offsets, especially on ALOS images, show that there is a large amount of right-lateral slip (1-3 m) on a previously unmapped system of faults extending about 60 km to the southeast of the epicenter beneath the Colorado River Delta named the Indiviso Fault system. Aftershocks also extend approximately the same distance to the southeast. InSAR analyses of Envisat, ALOS and UAVSAR images, measure the surface displacements in the same radar line-of-sight as the range pixel tracking, but with much greater precision. Combination of SAR images from different directions allows the separation of the vertical and east components of the deformation, revealing the large normal fault slip in the Sierra Cucapah (down to the east) and blocks with substantial vertical motion in the Delta (both down to the east and down to the west). Kinematic finite fault modeling shows a bilateral rupture with fault slip shallower than 10 km on the faults to the NW and SE of the epicenter. The InSAR also reveals slip on many minor faults on both sides of the Sierra Cucapah and to the northwest, with displacements of cm to 10’s of cm. High-resolution UAVSAR coseismic and postseismic interferograms revealed triggered slip on a number of faults in the Yuha desert and Salton Trough, with some slip occurring in the three months after the main shock. Postseismic InSAR shows rapid afterslip on shallow faults at the north and south ends of the main coseismic rupture. Areas of the Colorado River Delta that subsided during the main earthquake continued to subside afterwards. Larger spatial scales of postseismic deformation that would be expected from viscoelastic relaxation are difficult to measure in the InSAR data because of large variations in tropospheric water vapor.

Fielding, E. J.; Wei, S.; Leprince, S.; Sladen, A.; Simons, M.; Avouac, J.; Briggs, R. W.; Hudnut, K. W.; Helmberger, D. V.; Hensley, S.; Hauksson, E.; Gonzalez-Garcia, J. J.; Herring, T.; Akciz, S. O.

2010-12-01

28

Electro-optical hybrid slip ring  

Microsoft Academic Search

The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone

En Hong

2005-01-01

29

Electro-optical hybrid slip ring  

NASA Astrophysics Data System (ADS)

The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone wires dangling from moving joints. Slip rings are widely used for testing, evaluating, developing and improving various technical equipment and facilities with rotating parts. They are widely used in industry, especially in manufacturing industries employing turbo machinery, as in aviation, shipbuilding, aerospace, defense, and in precise facilities having rotating parts such as medical Computerized Tomography (CT) and MRI scanners and so forth. Therefore, any improvement in slip ring technology can impact large markets. Research and development in this field will have broad prospects long into the future. The goal in developing the current slip ring technology is to improve and increase the reliability, stability, anti-interference, and high data fidelity between rotating and stationary structures. Up to now, there have been numerous approaches used for signal and data transfer utilizing a slip ring such as metal contacts, wires, radio transmission, and even liquid media. However, all suffer from drawbacks such as data transfer speed limitations, reliability, stability, electro-magnetic interference and durability. The purpose of the current research is to break through these basic limitations using an optical solution, thereby improving performance in current slip ring applications. This dissertation introduces a novel Electro-Optical Hybrid Slip Ring technology, which makes "through the air" digital-optical communication between stationary and rotating systems a reality with high data transfer speed, better reliability and low interference susceptibility. A laboratory scale non-contact Electro-Optical Hybrid Slip Ring system was successfully constructed, and its performance was determined. Experimental results affirmed the advantages of this new technology over current slip ring design.

Hong, En

2005-11-01

30

Acoustic emissions during deformation of jointed rock  

SciTech Connect

As an aid to understanding and monitoring the behavior of jointed rock masses, we have done a series of experiments on samples of Grouse Canyon tuff containing sawcut joints. The tuff was selected because it is under consideration as a disposal medium for nuclear wastes. The samples were instrumented to measure axial and transverse displacements and AE rates. Testing was done in a servocontrolled machine at displacement rates of 2 x 10{sup -5} in/sec, and confining pressures ranging from 1500 to 6000 psi. Four modes of slip on joints were identified. First, stable sliding accompanied by a steady rate of AE. Second, stick-slip with a sharp drop in load, large displacements but no premonitory AE or slip. Third, stick-slip, as in mode 2, but with premonitory AE and slip. Fourth, stable stick-slip where the load dropped and the displacements increased but the process was slow and culminated in stable sliding. Mode 4 exhibited premonitory AE and slip and after the event, a steady rate of AE during sliding. In all cases where premonitory slip or stable sliding occurred there was a corresponding occurrence of AE, indicating slip is related to damage to the joint surfaces and adjacent material. Monitoring AE would be a useful method of detecting slip and the extent of slip in modes 1, 3, and 4. Increasing slip rate leads to increasing AE rate. However, mode 2 stick-slip appears to be undetectable by this method.

Holcomb, D.J.; Teufel, L.W.

1984-12-31

31

Contactless Magnetic Slip Ring  

NASA Technical Reports Server (NTRS)

A contactless magnetic slip ring is disclosed having a primary coil and a secondary coil. The primary and secondary coils are preferably magnetically coupled together, in a highly reliable efficient manner, by a magnetic layered core. One of the secondary and primary coils is rotatable and the contactless magnetic slip ring provides a substantially constant output.

Kumagai, Hiroyuki (Inventor); Deardon, Joe D. (Inventor)

1997-01-01

32

SlipKnot Home Page  

NSDL National Science Digital Library

SlipKnot (w/o SLIP) MicroMind, New York, NY, US SlipKnot is a graphical World Wide Web browser specifically designed for Microsoft Windows users who have UNIX shell accounts with their service providers. Its primary feature is that it does not require SLIP or PPP or TCP/IP services. SlipKnot is distributed as restricted shareware, with a registration fee.

33

Episodic silence and slip (Invited)  

NASA Astrophysics Data System (ADS)

Conditions in the transition zone between seismogenic and stable slip produce hybrid events where slip occurs as slow earthquakes. In Cascadia, these slow earthquakes are consistently observed as slow interface-slip accompanied by persistent tectonic tremor. However, not all slow slip at other plate boundaries coincides with observed tremor, leaving the physics of tremor generation and the connection between tremor and slow slip poorly understood. Here we analyze seismic, geodetic and borehole strainmeter data to observe a large, tremor-generating slow earthquake temporarily fall silent in the middle of its along-strike rupture. This gap, where low slip-rate slip continues without tremor, occurs on a portion of the fault that has repeatedly produced tremor in past events and later generates tremor as higher slip-rate slip back-propagates into it. The finding suggests that, depending on the slip rate, the same episode can change from tremorgenic, to silent and back again, and the same section of fault can slip both with and without tremor. This result emphasizes slip speed and/or current stress state over fault rheology as a controlling factor, providing an important clue for understanding the physics of tremor generation and the relationship between tremor and slip. The result also underscores the potential role of aseismic slip in accommodating plate motion and the limitations of using tremor as a proxy for slip.

Wech, A.; Bartlow, N. M.

2013-12-01

34

Static stress drop associated with brittle slip events on exhumed faults  

Microsoft Academic Search

We estimate the static stress drop on small exhumed strike-slip faults in the Lake Edison granodiorite of the central Sierra Nevada (California). The subvertical strike-slip faults were exhumed from 4 to 15 km depth and were chosen because they are exposed in outcrop along their entire tip-to-tip lengths of 8–12 m. Slip nucleated on joints and accumulated by crystal-plastic shearing

W. A. Griffith; G. Di Toro; G. Pennacchioni; D. D. Pollard; S. Nielsen

2009-01-01

35

Slipping-rib syndrome.  

PubMed

A survey of 46 patients with the slipping-rib syndrome shows that it is a condition which affects mainly middle-aged people. It is equally common in men and women. The main symptom is upper abdominal pain, equally common on either side and occasionally bilateral. The pain is precipitated by movement and certain postures and is faithfully reproduced by pressure at one or more points on the costal margin. The cause of the "slipping rib" is not known. Symptoms are relieved by reassurance and in some cases by injection of local anaesthetic into painful sites. PMID:6107417

Wright, J T

1980-09-20

36

The slipping rib syndrome.  

PubMed

The slipping rib syndrome is a cause of upper abdominal pain that is not widely known, possibly because of failure of recognition rather than infrequent occurrence. The syndrome should be suspected when pain can be reproduced by a rib-hooking maneuver. However, a thorough evaluation including intercostal nerve blocks is necessary both to eliminate coexistent gastrointestinal and psychiatric disorders as a cause of pain and to assure adequate treatment and a good prognosis. Patients with obvious slipping ribs appear to benefit from surgical excision. PMID:6639342

Spence, E K; Rosato, E F

1983-11-01

37

The frictional properties of joints in rock  

Microsoft Academic Search

Summary The conditions for sliding over artificial joint surfaces have been studied experimentally by cutting rock cylinders at various angles to their axes and studying slip over these surfaces in a triaxial testing apparatus. The types of joint used were: (i) filled with plaster to simulate a soft joint filling, (ii) bare surfaces ground approximately flat, and (iii) natural surfaces

J. C. Jaeger

1959-01-01

38

Distribution of slip from 11 Mw > 6 earthquakes in the northern Chile subduction zone  

E-print Network

Distribution of slip from 11 Mw > 6 earthquakes in the northern Chile subduction zone M. E to constrain the relative location of coseismic slip from 11 earthquakes on the subduction interface both jointly and separately for the four largest earthquakes during this time period (1993 Mw 6.8; 1995

Simons, Mark

39

Slip Rates on young faults  

NSDL National Science Digital Library

Students use measured ages and offset of quaternary surfaces to determine vertical slip rates of a young fault. Students then must determine if vertical slip rates have varied significantly through time.

Huerta, Audrey

40

Slipping rib syndrome.  

PubMed

Three cases of slipping rib syndrome are presented. The pertinent anatomy of the costal margin and nerve supply are reviewed. The treatment of the disease is presented along with case histories. This entity is little known to the medical profession, although first described in 1919. Probably far more common than is realized, it should always be included in the differential diagnosis of thoracic and abdominal pain. PMID:501752

Bass, J; Pan, H C; Fegelman, R H

1979-09-01

41

Slipping Rib Syndrome  

PubMed Central

Three cases of slipping rib syndrome are presented. The pertinent anatomy of the costal margin and nerve supply are reviewed. The treatment of the disease is presented along with case histories. This entity is little known to the medical profession, although first described in 1919. Probably far more common than is realized, it should always be included in the differential diagnosis of thoracic and abdominal pain. PMID:501752

Bass, James; Pan, Huai C.; Fegelman, Ronald H.

1979-01-01

42

Acoustic emissions during deformation of intact and jointed welded tuff  

SciTech Connect

Monitoring of acoustic emissions (AE) has been widely used as a means of detecting failure in intact rock. For intact rock the technique is simple, because an increasing rate of AE is usually a sign of impending failure. However, most large rock masses contain numerous joints and the behavior of the joints controls the properties of the rock mass. In particular, the failure mode often becomes stable or unstable slip (stick-slip) on a joint at stresses well below those required for failure of the intact rock. As an aid to understanding and monitoring the behavior of jointed rock masses, we have done a series of experiments on intact and artificially jointed samples of Grouse Canyon tuff. The tuff was selected because it is under consideration as a disposal medium for nuclear wastes. The samples were instrumented to measure axial and transverse displacements and AE rates. Testing was done in a servo-controlled machine at axial displacement rates of 5 x 10{sup -5} cm/sec, and confining pressures ranging from 10 to 40 MPa. For the jointed samples four modes of slip were identified. First, stable sliding accompanied by a steady rate of AE. Second, stick-slip with a sharp drop in load, large displacements but no premonitory AE or slip. Third, stick-slip, as in mode 2, but with premonitory AE and slip. Fourth, slow stick-slip where the load dropped and the displacements increased but the process was slow and culminated in stable sliding. Mode 4 exhibited premonitory AE and slip and after the event, a steady rate of AE during sliding. There seemed to be no way to predict which mode would occur at a given point in the test. In all cases where stable or unstable slip occurred there was a corresponding occurrence of AE. This indicates that slip is related to damage to the joint surfaces and adjacent material. Monitoring AE would be a useful method of detecting slip.

Holcomb, D.J.; Teufel, L.W.

1982-07-01

43

Development of Structure and Slip Along Strike-slip Faults Near Pear Lake, Sequoia National Park, California  

NASA Astrophysics Data System (ADS)

Mapping and a mechanical analysis of strike-slip faults hosted in the granitic rock of Sequoia National Park, California provide new insight into the effects of pre-existing structures on fault growth and the partitioning of fault slip. The longest fault we identified near Pear Lake has a trace length of approximately 7 km with a fault structure consisting of several sub-parallel ENE striking fault segments linked together by a complex network of smaller NE striking segments. The ENE segments exploited aplitic dikes, whereas the NE trending segments are slipped regional joints. Previous work has shown that Sierran faults and shear zones have nucleated on pre-existing joints and dikes, respectively, but the discovery that "brittle" faults can nucleate from dikes is new. In this case, the dikes developed into faults as closely-spaced echelon joints striking NE developed within the dikes, eventually weakening them enough that they failed as shear fractures. These faulted dikes are currently expressed as prominent topographic troughs with pieces of aplite on the margins of the trough walls. This mechanism can explain how faults can grow to lengths of several kilometers or more and still maintain a nearly planar character. Measurements of offset dikes along the Pear Lake fault reveal a lateral separation profile that can be described as perturbed elliptical distribution. This is one of the first documented slip profiles we know of for an intra-plate strike-slip fault of its size in crystalline rock. The ratio of the maximum measured slip (75-95 m) to fault trace length is 0.01; measurements along two nearby faults that are roughly parallel yield a similar ratio. The spacing between these faults is roughly 1/4 to 1/2 of their trace lengths, so if the faults slipped contemporaneously, then they must have interacted mechanically as they grew. This network of parallel strands and the segments linking them together results in a partitioning of slip where areas of anomalously low slip on the Pear Lake fault are roughly balanced by slip on neighboring segments. >http://www.soest.hawaii.edu/martel/Stevem.html

Martel, S. J.; d'Alessio, M.

2001-12-01

44

Formation and Suppression of Strike-Slip Fault Systems  

NASA Astrophysics Data System (ADS)

Strike-slip faults are a defining feature of plate tectonics, yet many aspects of their development and evolution remain unresolved. For intact materials and/or regions, a standard sequence of shear development is predicted from physical models and field studies, commencing with the formation of Riedel shears and culminating with the development of a throughgoing fault. However, for materials and/or regions that contain crustal heterogeneities (normal and/or thrust faults, joints, etc.) that predate shear deformation, kinematic evolution of strike-slip faulting is poorly constrained. We present a new plane-stress finite-strain physical analog model developed to investigate primary deformation zone evolution in simple shear, pure strike-slip fault systems in which faults or joints are present before shear initiation. Experimental results suggest that preexisting mechanical discontinuities (faults and/or joints) have a marked effect on the geometry of such systems, causing deflection, lateral distribution, and suppression of shears. A lower limit is placed on shear offset necessary to produce a throughgoing fault in systems containing preexisting structures. Fault zone development observed in these experiments provides new insight for kinematic interpretation of structural data from strike-slip fault zones on Earth, Venus, and other terrestrial bodies.

Curren, Ivy S.; Bird, Peter

2014-11-01

45

Slip partitioning by elastoplastic propagation of oblique slip at depth.  

PubMed

Oblique motion along tectonic boundaries is commonly partitioned into slip on faults with different senses of motion. The origin of slip partitioning is important to structural geology, tectonophysics, and earthquake mechanics. Partitioning can be explained by the upward elastoplastic propagation of oblique slip from a fault or shear zone at depth. The strain field ahead of the propagating fault separates into zones of predominantly normal, reverse, and strike-slip faulting. The model successfully predicts the distribution of fault types along parts of the San Andreas and Haiyuan faults. PMID:12750513

Bowman, David; King, Geoffrey; Tapponnier, Paul

2003-05-16

46

SlipChip†  

PubMed Central

The SlipChip is a microfluidic device designed to perform multiplexed microfluidic reactions without pumps or valves. The device has two plates in close contact. The bottom plate contains wells preloaded with many reagents; in this paper plates with 48 reagents were used. These wells are covered by the top plate that acts as a lid for the wells with reagents. The device also has a fluidic path, composed of ducts in the bottom plate and wells in the top plate, which is connected only when the top and bottom plate are aligned in a specific configuration. Sample can be added into the fluidic path, filling both wells and ducts. Then, the top plate is “slipped”, or moved, relative to the bottom plate so the complementary patterns of wells in both plates overlap, exposing the sample-containing wells of the top plate to the reagent-containing wells of the bottom plate, and enabling diffusion and reactions. Between the two plates, a lubricating layer of fluorocarbon was used to facilitate relative motion of the plates. This paper implements this approach on a nanoliter scale using devices fabricated in glass. Stability of preloaded solutions, control of loading, and lack of cross-contamination were tested using fluorescent dyes. Functionality of the device was illustrated via crystallization of a model membrane protein. Fabrication of this device is simple and does not require a bonding step. This device requires no pumps or valves and is applicable to resource-poor settings. Overall, this device should be valuable for multiplexed applications that require exposing one sample to many reagents in small volumes. One may think of the SlipChip as an easy-to-use analogue of a preloaded multi-well plate, or a preloaded liquid-phase microarray. PMID:19636458

Du, Wenbin; Li, Liang; Nichols, Kevin P.; Ismagilov, Rustem F.

2009-01-01

47

Universal behavior in ideal slip  

NASA Technical Reports Server (NTRS)

The slip energies and stresses are computed for defect-free crystals of Ni, Cu, Ag, and Al using the many-atom approach. A simple analytical expression for the slip energies is obtained, leading to a universal form for slip, with the energy scaled by the surface energy and displacement scaled by the lattice constant. Maximum stresses are found to be somewhat larger than but comparable with experimentally determined maximum whisker strengths.

Bozzolo, Guillermo; Ferrante, John; Smith, John R.

1991-01-01

48

Slipping rib syndrome.  

PubMed

Slipping rib syndrome is a rare and underdiagnosed condition. Since approximately one third of the cases reported to date have involved patients considered to be psychoneurotic and/or who have undergone psychiatric evaluation, a conservative treatment approach is recommended. Many patients respond to simple reassurance, and in others, a single intercostal nerve block provides lasting relief. In the case reported here, radicular pain, a history of injury to the affected side, noncontributory findings on ancillary investigations, a positive response to the hooking maneuver, and relief of pain after intercostal nerve block led to the diagnosis. PMID:2813218

Abbou, S; Herman, J

1989-11-01

49

{110} Slip with {112} slip traces in bcc Tungsten.  

PubMed

While propagation of dislocations in body centered cubic metals at low temperature is understood in terms of elementary steps on {110} planes, slip traces correspond often with other crystallographic or non-crystallographic planes. In the past, characterization of slip was limited to post-mortem electron microscopy and slip trace analysis on the sample surface. Here with in-situ Laue diffraction experiments during micro-compression we demonstrate that when two {110} planes containing the same slip direction experience the same resolved shear stress, sharp slip traces are observed on a {112} plane. When however the {110} planes are slightly differently stressed, macroscopic strain is measured on the individual planes and collective cross-slip is used to fulfill mechanical boundary conditions, resulting in a zig-zag or broad slip trace on the sample surface. We anticipate that such dynamics can occur in polycrystalline metals due to local inhomogeneous stress distributions and can cause unusual slip transfer among grains. PMID:23989456

Marichal, Cecile; Van Swygenhoven, Helena; Van Petegem, Steven; Borca, Camelia

2013-01-01

50

{110} Slip with {112} slip traces in bcc Tungsten  

PubMed Central

While propagation of dislocations in body centered cubic metals at low temperature is understood in terms of elementary steps on {110} planes, slip traces correspond often with other crystallographic or non-crystallographic planes. In the past, characterization of slip was limited to post-mortem electron microscopy and slip trace analysis on the sample surface. Here with in-situ Laue diffraction experiments during micro-compression we demonstrate that when two {110} planes containing the same slip direction experience the same resolved shear stress, sharp slip traces are observed on a {112} plane. When however the {110} planes are slightly differently stressed, macroscopic strain is measured on the individual planes and collective cross-slip is used to fulfill mechanical boundary conditions, resulting in a zig-zag or broad slip trace on the sample surface. We anticipate that such dynamics can occur in polycrystalline metals due to local inhomogeneous stress distributions and can cause unusual slip transfer among grains. PMID:23989456

Marichal, Cecile; Van Swygenhoven, Helena; Van Petegem, Steven; Borca, Camelia

2013-01-01

51

Slips of the typewriter key  

Microsoft Academic Search

This article presents an analysis of 500 submorphemic slips of the typewriter key that escaped the notice of authors and other proofreaders and thereby made their way into the published records of scientific research. Despite this high selectivity, the corpus is not found to differ in major ways from other collections of keying slips. The main characteristics of this error

THOMAS BERG

2002-01-01

52

Joint swelling  

MedlinePLUS

Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

53

Slipped capital femoral epiphysis caused by neurogenic heterotopic ossification.  

PubMed

Slipped capital femoral epiphysis (SCFE) is rare in nonambulatory patients, as mechanical factors play important roles in the development of the disease. We report a case of SCFE, which occurred in a 12-year-old girl with a nonambulatory status after cerebral infarction. SCFE occurred after she received passive range of motion exercise and extracorporeal shock wave treatment for neurogenic heterotopic ossification around the hip joint. The patient was successfully managed by a stepwise approach, with radiological and clinical improvements. PMID:23969564

Chang, Sam Yeol; Yoo, Won Joon; Park, Moon Seok; Chung, Chin Youb; Choi, In Ho; Cho, Tae-Joon

2013-11-01

54

An analysis of a joint shear model for jointed media with orthogonal joint sets; Yucca Mountain Site Characterization Project  

SciTech Connect

This report describes a joint shear model used in conjunction with a computational model for jointed media with orthogonal joint sets. The joint shear model allows nonlinear behavior for both joint sets. Because nonlinear behavior is allowed for both joint sets, a great many cases must be considered to fully describe the joint shear behavior of the jointed medium. An extensive set of equations is required to describe the joint shear stress and slip displacements that can occur for all the various cases. This report examines possible methods for simplifying this set of equations so that the model can be implemented efficiently form a computational standpoint. The shear model must be examined carefully to obtain a computationally efficient implementation that does not lead to numerical problems. The application to fractures in rock is discussed. 5 refs., 4 figs.

Koteras, J.R.

1991-10-01

55

Slips of the Typewriter Key.  

ERIC Educational Resources Information Center

Presents an analysis of 500 submorphemic slips of the typewriter key that escaped the notice of authors and other proofreaders and thereby made their way into the published records of scientific research. (Author/VWL)

Berg, Thomas

2002-01-01

56

Slipping and Rolling Wheel Model  

NSDL National Science Digital Library

The EJS Slipping and Rolling Wheel Model shows the motion of a wheel rolling on a floor subject to friction. The simulation allows the user to change the initial translational and rotational velocities of the wheel, v and ω, the mass, radius, and mass distribution, R, m, and C of the wheel. By controlling these variables, the dynamics of the wheel can be changed to show the sliding, then rolling without slipping, of the wheel. The Slipping and Rolling Wheel Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_newton_SlippingRollingWheel.jar file will run the program if Java is installed. The user can modify this simulation if EJS is installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item.

Christian, Wolfgang; Belloni, Mario

2009-02-26

57

Development of strike-slip faults from dikes, Sequoia National Park, California  

NASA Astrophysics Data System (ADS)

Faults several kilometers long near Pear Lake in Sequoia National Park, California nucleated on preexisting dikes weakened by closely-spaced échelon joints. These joints essentially parallel much more widely spaced regional joints. Fault nucleation by dike fracturing can explain how a nearly planar fault can grow to lengths of several kilometers or more. We suggest that opening mode fractures, including dikes, might serve more commonly as nuclei for faults than is generally appreciated. The longest fault in the study area, the Pear Lake fault, has a trace length of ˜7 km and a maximum measured lateral separation of 86-98 m. A sharp decrease in slip occurs near the center of the trace of the Pear Lake fault where another fault branches from it. Mechanical analyses demonstrate that a sharp decrease in slip is expected where a fault branches. All the faults near Pear Lake show non-elliptical slip distributions. Based on our mechanical analyses, we infer that the observed slip distributions reflect a mechanical interaction among the faults. The geometry and distribution of structures that precede faulting (i.e. dikes and joints) control to a large extent the structure of a fault network and hence the ultimate slip distribution on faults in the network.

d'Alessio, Matthew; Martel, Stephen J.

2005-01-01

58

Earthquake slip distribution estimation, using a random vector approach  

NASA Astrophysics Data System (ADS)

InSAR and/or GNSS data are routinely used to invert for the slip distribution on faults that rupture during earthquakes. Where exactly slip occurred has implications for future seismic hazard. However, in order to regularize the inversion, extra assumptions about the smoothness of the slip distribution are usually included, which do not have a physical basis. Here we propose a new approach for constraining the slip distribution based on a random vector model following a von Karman autocorrelation function. While this approach also has no physical basis, it does have empirical support from a stochastic analysis of seismic finite-source slip inversions (Mai and Beroza, 2002). We implement the random vector constraint in a Bayesian fashion and use a Markov chain Monte Carlo (MCMC) algorithm to derive the posterior joint probability distribution for each of the slipping patches. The von Karman function depends on two parameters: correlation length and Hurst number (related to fractal dimension). We use histograms from the stochastic analysis for these two parameters, which differ in along-strike and down-dip directions, to derive prior probability distributions, but allow them to vary during the inversion as hyperparameters. We also let the model parameters that control the fault geometry vary freely. In other inversion approaches these are usually fixed prior to inversion for distributed slip, due primarily to the difficulty in searching the resulting model space within a reasonable CPU time. To overcome this problem we have implemented a variation to the usual MCMC approach, in which the step size for each of the model parameters is regularly updated to optimize convergence time. We have applied our approach to a number of earthquakes and find that the results sometimes differ markedly to those incorporating the common Laplacian smoothing constraint. In addition, the fast run times mean that this approach could be routinely applied to data from the upcoming Sentinel-1 mission to automatically derive slip distributions for all earthquakes that cause significant surface displacement. References: Mai, P. M., and G. C. Beroza (2002), A spatial random field model to characterize complexity in earthquake slip, J. Geophys. Res., 107(B11), 2308.

Hooper, A. J.

2012-12-01

59

Flow-induced vibrations-1987  

SciTech Connect

This book contains 20 selections. Some of the titles are: Acoustic resonance in heat exchanger tube bundles--Part 1. Physical nature of the phenomenon; Theoretical and experimental studies on heat exchanger U-bend tube bundle vibration characteristics; Experimental model analysis of metallic pipeline conveying fluid; Leakage flow-induced vibration of an eccentric tube-in-tube slip joint; and A study on the vibrations of pipelines caused by internal pulsating flows.

Au-Yang, M.K.; Chen, S.S.

1987-01-01

60

Gross slip criteria in fretting  

NASA Astrophysics Data System (ADS)

Three sets of criteria for incipient gross slip in fretting are studied: fretting scar morphology, tangential force and displacement amplitude interrelations, and fretting energy dissipation. It is shown that scar morphologies characteristic of different fretting regimes can be identified. Some force-energy diagrams display force curves without well-defined critical force amplitude, rendering the force criterion difficult to apply. The energy curves always have a sharp bend corresponding to a change in energy dissipation characteristics at the gross slip transition. The energy criterion occurs for a lower critical displacement amplitude than the force criterion.

Vingsbo, Olof; Schon, Joakim

1993-04-01

61

Slipping rib syndrome in childhood.  

PubMed

Slipping rib syndrome is an unusual cause of lower chest and upper abdominal pain in children not mentioned in major pediatric surgical texts. The syndrome occurs when the medial fibrous attachments of the eighth, ninth, or tenth ribs are inadequate or ruptured, allowing their cartilage tip to slip superiorly and impinge on the intervening intercostal nerve. This may cause a variety of somatic and visceral complaints. Although the diagnosis may be made based on history and physical examination, lack of recognition of this disorder frequently leads to extensive diagnostic evaluations before definitive therapy. The authors report on four children who have this disorder. PMID:9247238

Mooney, D P; Shorter, N A

1997-07-01

62

Slip rate and tremor genesis in Cascadia  

NASA Astrophysics Data System (ADS)

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.

Wech, Aaron G.; Bartlow, Noel M.

2014-01-01

63

Bulk Metallic Glasses Deform via Slip Avalanches  

E-print Network

Inelastic deformation of metallic glasses occurs via slip events with avalanche dynamics similar to those of earthquakes. For the first time in these materials, measurements have been obtained with sufficiently high temporal resolution to extract both the exponents and the scaling functions that describe the nature, statistics and dynamics of the slips according to a simple mean-field model. These slips originate from localized deformation in shear bands. The mean-field model describes the slip process as an avalanche of rearrangements of atoms in shear transformation zones (STZs). Small slips show the predicted power-law scaling and correspond to limited propagation of a shear front, while large slips are associated with uniform shear on unconstrained shear bands. The agreement between the model and data across multiple independent measures of slip statistics and dynamics provides compelling evidence for slip avalanches of STZs as the elementary mechanism of inhomogeneous deformation in metallic glasses.

Antonaglia, James; Gu, Xiaojun; Byer, Rachel R; Hufnagel, Todd C; LeBlanc, Michael; Uhl, Jonathan T; Dahmen, Karin A

2013-01-01

64

Coseismic and postseismic slip of the 2004 Parkfield earthquake from space-geodetic data  

USGS Publications Warehouse

We invert interferometric synthetic aperture radar (InSAR) data jointly with campaign and continuous global positioning system (GPS) data for slip in the coseismic and postseismic periods of the 2004 Parkfield earthquake. The InSAR dataset consists of eight interferograms from data collected by the Envisat and Radarsat satellites spanning the time of the earthquake and variable amounts of the postseismic period. The two datasets complement each other, with the InSAR providing dense sampling of motion in the range direction of the satellite and the GPS providing more sparse, but three-dimensional measurements of ground motion. The model assumes exponential decay of the postseismic slip with a decay time constant of 0.087 years, determined from time series modeling of continuous GPS and creepmeter data. We find a geodetic moment magnitude of M 6.2 for a 1-day coseismic model and Mw 6.1 for the entire postseismic period. The coseismic rupture occurred mainly in two slip asperities; one near the hypocenter and the other 15-20 km north. Postseismic slip occurred on the shallow portions of the fault and near the rupture areas of two M 5.0 aftershocks. A comparison of the geodetic slip models with seismic moment estimates suggests that the coseismic moment release of the Parkfield earthquake is as little as 25% of the total. This underlines the importance of aseismic slip in the slip budget for the Parkfield segment.

Johanson, I.A.; Fielding, E.J.; Rolandone, F.; Burgmann, R.

2006-01-01

65

What Is an Earthquake?: Oblique Slip  

NSDL National Science Digital Library

Some faults experience appreciable amounts of dip slip and strike slip simultaneously, and the nomenclature of these faults reflects this. This is an exercise regarding the nomenclature of faults that experience appreciable amounts of dip slip and strike slip simultaneously. In this activity, learners view animations of these faults and attempt to correctly interpret the sense of motion. Clicking on the completed animation provides the correct answer.

66

Slip instability and state variable friction laws  

Microsoft Academic Search

The dependence of the friction on slip history is described by an experimentally motivated constitutive law where the friction is dependent on slip rate and state variables. The state variables are defined macroscopically by evolution equations for their rates of change in terms of their present values and slip rate. Experiments may strongly suggest that one state variables is adequate

Andy Ruina

1983-01-01

67

Slipping properties of ceramic tiles / Quantification of slip resistance  

NASA Astrophysics Data System (ADS)

Regarding the research and application of ceramic tiles there is a great importance of defining precisely the interaction and friction between surfaces. Measuring slip resistance of floor coverings is a complex problem; slipperiness is always interpreted relatively. In the lack of a consistent and clear EU standard, it is practical to use more method in combination. It is necessary to examine the structure of materials in order to get adequate correlation. That is why measuring techniques of surface roughness, an important contributor to slip resistance and cleaning, is fundamental in the research. By comparing the obtained test results, relationship between individual methods of analysis and values may be determined and based on these information recommendations shall be prepared concerning the selection and application of tiles.

Terjek, Anita

2013-12-01

68

Origin of anomalous slip in tungsten.  

PubMed

Low-temperature deformation of body-centered cubic metals shows a significant amount of plastic slip on planes with low shear stresses, a phenomenon called anomalous slip. Despite progress in atomistic modeling of the consequences of complex stress states on dislocation mobility, the phenomenon of anomalous slip remained elusive. Using in situ Laue microdiffraction and discrete dislocation dynamics in micrometer sized tungsten single crystals, we demonstrate the occurrence of significant anomalous slip. It occurs as a consequence of cross kinks, topological configurations generated by prior dislocation interactions. This clearly identifies anomalous slip as a multidislocation process and not a property of isolated dislocations. The cross-kink mechanism also explains the ambiguous reporting of anomalous slip traces in the past and directs us to ways of including anomalous slip in continuum crystal plasticity formulations. PMID:25062203

Marichal, C; Srivastava, K; Weygand, D; Van Petegem, S; Grolimund, D; Gumbsch, P; Van Swygenhoven, H

2014-07-11

69

Origin of Anomalous Slip in Tungsten  

NASA Astrophysics Data System (ADS)

Low-temperature deformation of body-centered cubic metals shows a significant amount of plastic slip on planes with low shear stresses, a phenomenon called anomalous slip. Despite progress in atomistic modeling of the consequences of complex stress states on dislocation mobility, the phenomenon of anomalous slip remained elusive. Using in situ Laue microdiffraction and discrete dislocation dynamics in micrometer sized tungsten single crystals, we demonstrate the occurrence of significant anomalous slip. It occurs as a consequence of cross kinks, topological configurations generated by prior dislocation interactions. This clearly identifies anomalous slip as a multidislocation process and not a property of isolated dislocations. The cross-kink mechanism also explains the ambiguous reporting of anomalous slip traces in the past and directs us to ways of including anomalous slip in continuum crystal plasticity formulations.

Marichal, C.; Srivastava, K.; Weygand, D.; Van Petegem, S.; Grolimund, D.; Gumbsch, P.; Van Swygenhoven, H.

2014-07-01

70

Fault roughness evolution with slip (Gole Larghe Fault Zone, Italian Alps)  

NASA Astrophysics Data System (ADS)

Fault surface roughness is a principal factor influencing fault and earthquake mechanics. However, little is known on roughness of fault surfaces at seismogenic depths, and particularly on how it evolves with accumulating slip. We have studied seismogenic fault surfaces of the Gole Larghe Fault Zone, which exploit precursor cooling joints of the Adamello tonalitic pluton (Italian Alps). These faults developed at 9-11 km and 250-300°C. Seismic slip along these surfaces, which individually accommodated from 1 to 20 m of net slip, resulted in the production of cm-thick cataclasites and pseudotachylytes (solidified melts produced during seismic slip). The roughness of fault surfaces was determined with a multi-resolution aerial and terrestrial LIDAR and photogrammetric dataset (Bistacchi et al., 2011, Pageoph, doi: 10.1007/s00024-011-0301-7). Fault surface roughness is self-affine, with Hurst exponent H < 1, indicating that faults are comparatively smoother at larger wavelengths. Fault surface roughness is inferred to have been inherited from the precursor cooling joints, which show H ? 0.8. Slip on faults progressively modified the roughness distribution, lowering the Hurst exponent in the along-slip direction up to H ? 0.6. This behaviour has been observed for wavelengths up to the scale of the accumulated slip along each individual fault surface, whilst at larger wavelengths the original roughness seems not to be affected by slip. Processes that contribute to modify fault roughness with slip include brittle failure of the interacting asperities (production of cataclasites) and frictional melting (production of pseudotachylytes). To quantify the "wear" due to these processes, we measured, together with the roughness of fault traces and their net slip, the thickness and distribution of cataclasites and pseudotachylytes. As proposed also in the tribological literature, we observe that wearing is scale dependent, as smaller wavelength asperities have a shorter interaction distance and are consumed faster with slip than larger ones. However, in faults, production of cataclasites and pseudotachylytes changes the contact area of sliding surfaces by interposing a layer of wear products. This layer may preserve from wearing asperities that are smaller in amplitude than the layer thickness, thus providing a mechanism that is likely to preserve small amplitude/wavelength roughness. These processes have been considered in a new spectral model of wear, which allows to model wear for self-affine surfaces and includes the accumulation of wear products within the fault zone. This model can be used to generalize our results and contribute to reconstruct a realistic model of a seismogenic fault zone (http://roma1.rm.ingv.it/laboratori/laboratorio-hp-ht/usems-project).

Bistacchi, A.; Spagnuolo, E.; Di Toro, G.; Nielsen, S. B.; Griffith, W. A.

2011-12-01

71

Hip joints  

NSDL National Science Digital Library

The human hips are an example of a ball-and-socket joint. Ball-and-socket joints have the ability to rotate in a circular motion. The joint where the arm connects to the shoulder is also a type of ball-and-socket joint.

Connie Raab (National Institutes of Health;)

2006-05-17

72

Detailed joint structure in a geothermal reservoir from studies of induced microearthquake clusters  

Microsoft Academic Search

Microearthquake clusters form distinct, planar patterns within five study regions of a geothermal reservoir undergoing hydraulic fracturing at Fenton Hill, New Mexico. The patterns define individual, slipping joint surfaces of dimension 40â120 m, containing 80â150 events each. Sharp, straight edges truncate the clusters, apparently intersections with aseismic joints. Each edge orientation is consistent with an intersection between the active joint

W. Scott Phillips; Leigh S. House; Michael C. Fehler

1997-01-01

73

Process for slip casting textured tubular structures  

DOEpatents

A process for centrifugal slip casting a textured hollow tube. A slip made up of a carrier fluid and a suspended powder is introduced into a porous mold which is rotated at a speed sufficient to create a centrifugal force that forces the slip radially outward toward the inner surface of the mold. The suspended powder, which is formed of particles having large dimensional aspect ratios such as particles of superconductive BSCCO, settles in a textured fashion radially outward toward the mold surface. The carrier fluid of the slip passes by capillary action radially outward around the settled particles and into the absorbent mold. A layer of mold release material is preferably centrifugally slip cast to cover the mold inner surface prior to the introduction of the BSCCO slip, and the mold release layer facilitates removal of the BSCCO greenbody from the mold without fracturing.

Steinlage, Greg A. (West Lafayette, IN); Trumble, Kevin P. (West Lafayette, IN); Bowman, Keith J. (West Lafayette, IN)

2002-01-01

74

Learning to predict slip for ground robots  

NASA Technical Reports Server (NTRS)

In this paper we predict the amount of slip an exploration rover would experience using stereo imagery by learning from previous examples of traversing similar terrain. To do that, the information of terrain appearance and geometry regarding some location is correlated to the slip measured by the rover while this location is being traversed. This relationship is learned from previous experience, so slip can be predicted later at a distance from visual information only.

Angelova, Anelia; Matthies, Larry; Helmick, Daniel; Sibley, Gabe; Perona, Pietro

2006-01-01

75

Development of a liquid metal slip ring  

NASA Technical Reports Server (NTRS)

A liquid metal slip ring/solar orientation mechanism was designed and a model tested. This was a follow-up of previous efforts for the development of a gallium liquid metal slip ring in which the major problem was the formation and ejection of debris. A number of slip ring design approaches were studied. The probe design concept was fully implemented with detail drawings and a model was successfully tested for dielectric strength, shock vibration, acceleration and operation. The conclusions are that a gallium liquid metal slip ring/solar orientation mechanism is feasible and that the problem of debris formation and ejection has been successfully solved.

Weinberger, S. M.

1972-01-01

76

On Versus Slip in BCC Metals  

Microsoft Academic Search

The problem of competition between {110} slip and \\\\{1\\\\bar{1}0\\\\} or \\\\{\\\\bar{1}\\\\bar{1}2\\\\} slip in bcc metals has been analyzed using crystal plasticity theory. It is concluded that \\\\{1\\\\bar{1}0\\\\} slip will occur in preference to {110} if the critical resolved shear stress ratio, tau\\\\{110\\\\}\\/tau\\\\{1\\\\bar{10\\\\}} exceeds 1.732; and that \\\\{\\\\bar{1}\\\\bar{1}2\\\\} slip will be preferred to {110} if the ratio tau\\\\{110\\\\}\\/tau\\\\{\\\\bar{1\\\\bar{1}2\\\\}} exceeds 2. These

Gilbert Y. Chin

1970-01-01

77

Bulk metallic glasses deform via slip avalanches.  

PubMed

For the first time in metallic glasses, we extract both the exponents and scaling functions that describe the nature, statistics, and dynamics of slip events during slow deformation, according to a simple mean field model. We model the slips as avalanches of rearrangements of atoms in coupled shear transformation zones (STZs). Using high temporal resolution measurements, we find the predicted, different statistics and dynamics for small and large slips thereby excluding self-organized criticality. The agreement between model and data across numerous independent measures provides evidence for slip avalanches of STZs as the elementary mechanism of inhomogeneous deformation in metallic glasses. PMID:24785049

Antonaglia, James; Wright, Wendelin J; Gu, Xiaojun; Byer, Rachel R; Hufnagel, Todd C; LeBlanc, Michael; Uhl, Jonathan T; Dahmen, Karin A

2014-04-18

78

The 1964 Prince William Sound earthquake: Joint inversion of tsunami and geodetic data  

Microsoft Academic Search

The 1964 Prince William Sound (Alaska) earthquake, Mw=9.2, ruptured a large area beneath the continental margin of Alaska from Prince William Sound to Kodiak Island. A joint inversion of tsunami waveforms and geodetic data, consisting of vertical displacements and horizontal vectors, gives a detailed slip distribution. Two areas of high slip correspond to seismologically determined areas of high moment release:

Jean M. Johnson; Kenji Satake; Sanford R. Holdahl; Jeanne Sauber

1996-01-01

79

Joint Disorders  

MedlinePLUS

A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including Arthritis - inflammation of a joint. It causes pain, stiffness, and swelling. Over time, ...

80

Acoustic emissions during deformation of intact and jointed welded tuff  

NASA Astrophysics Data System (ADS)

Monitoring of acoustic emissions (AE) has been widely used as a means of detecting failure in intact rock. For intact rock the technique is simple, because an increasing rate of AE is usually a sign of impending failure. However, most large rock masses contain numerous joints and the behavior of the joints controls the properties of the rock mass In particular, the failure mode often becomes stable or unstable slip (stick-slip) on a joint at stresses well below those required for failure of the intact rock. As an aid to understanding and monitoring the behavior of jointed rock masses, we have done a series of experiments on intact and artificially jointed samples of Grouse Canyon tuff. The tuff was selected because it is under consideration as a disposal medium for nuclear wastes. The samples were instrumented to measure axial and transverse displacements and AE rates.

Holcomb, D. J.; Teufel, L. W.

1982-07-01

81

Pulling by Pushing, Slip with Infinite Friction,  

E-print Network

Pulling by Pushing, Slip with Infinite Friction, and Perfectly Rough Surfaces Kevin M. Lynch the two objects even with an infinite coefficient of friction. Thus the common conception that infinite friction prevents slip is in error. This paper shows examples of the phenomena with both quasi

82

Salton Sea Satellite Image Showing Fault Slip  

USGS Multimedia Gallery

Landsat satellite image (LE70390372003084EDC00) showing location of surface slip triggered along faults in the greater Salton Trough area. Red bars show the generalized location of 2010 surface slip along faults in the central Salton Trough and many additional faults in the southwestern section of t...

83

Environmental study of miniature slip rings  

NASA Technical Reports Server (NTRS)

Investigation studied the long term operation of miniature slip ring assembles in high vacuum of space and included the influence of ring, brush, and insulator materials on electrical noise and mechanical wear. Results show that soft metal vapor plating and niobium diselenide miniature slip rings are beneficial.

Radnik, J. L.

1967-01-01

84

The role of water in slip casting  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

85

[Evaporating Droplet and Imaging Slip Flows  

NASA Technical Reports Server (NTRS)

In this report, we summarize work on Evaporating Droplet and Imaging Slip Flows. The work was primarily performed by post-doc Hue Hu, and partially by grad students Lei Li and Danish Chopra. The work includes studies on droplet evaporation and its effects on temperature and velocity fields in an evaporating droplet, new 3-D microscopic particle image velocimetry and direct visualization on wall slip in a surfactant solution. With the exception of the slip measurements, these projects were those proposed in the grant application. Instead of slip flow, the original grant proposed imaging electro-osmotic flows. However, shortly after the grant was issued, the PI became aware of work on electro-osmotic flows by the group of Saville in Princeton that was similar to that proposed, and we therefore elected to carry out work on imaging slip flows rather than electro-osmotic flows.

Larson, R. G.

2002-01-01

86

Suppression of strike-slip fault zones by preexisting crustal heterogeneities  

NASA Astrophysics Data System (ADS)

Although transform (strike-slip on land) faults are a defining feature of plate tectonics, plate boundary models show several regions where shearing is the primary regional deformation mechanism that completely lack or have underdeveloped strike-slip fault systems with respect to their slip rate. Regions that exhibit rapid toroidal (shearing) flow as indicated by GPS velocities, focal mechanisms, and/or neotectonic models but lack pervasive strike-slip faulting tend to possess common features that predate shearing, such as: (1) extensive fracturing perpendicular or sub-perpendicular to the shear plane (e.g., South Iceland Seismic Zone and Walker Lane, CA), and/or (2) regional cover of flood basalts or andesites containing columnar joints (e.g., Brothers Fault Zone, Oregon). We present a new plane-stress finite-strain analog model created to investigate the evolution of primary deformation zones in pure strike-slip fault systems where crustal heterogeneities emulating (1) and (2) exist prior to shear initiation. Experimental results indicate that, in comparison to systems with originally pristine surfaces, strike-slip fault systems containing preexisting structures develop more distributed geometries and that more than twice as much net offset is required for throughgoing strike-slip faulting to occur. These results provide new insight for kinematic interpretations of structural data from fault systems on Earth, Venus and other terrestrial bodies where crustal heterogeneities such as shear-plane perpendicular fractures and/or basaltic or andesitic flood basalts are present prior to shear initiation. Direct and independent confirmation of fault zone suppression could be provided through detailed geologic analyses of underdeveloped fault zones on Earth that exemplify the fault zone development observed in these experiments (e.g., Walker Lane, CA-NV).

Curren, I. S.; Bird, P.

2013-12-01

87

Methodology for the interpretation of fault-slip seismicity in a weak shear zone  

NASA Astrophysics Data System (ADS)

Fault-slip related seismic events that occur in underground mines could inflict severe damage to underground openings; thus a proper estimation of fault-slip potential in active mining areas is of paramount importance in assessing its risk. It is not uncommon in underground mines that large seismic events take place away from stopes being extracted, where fault-slip potential is presumed not to be high enough to result in those seismic events. In the present paper, fault-slip related seismic events taking place within a weak shear zone in Garson Mine, Sudbury, Canada are investigated. First, in order to understand the stress states of rockmass in the mine, numerical analysis is carried out with a 3D mine-wide model whilst assuming isotropic elasticity. The result obtained from the analysis reveals that the shear stress of rockmass in a weak shear zone does not reach the maximum shear strength determined by Mohr-Coulomb failure criterion with basic friction angles of the rockmass. The result contradicts a fact that quite a few seismic events have been actually recorded in the regions with micro seismic monitoring systems installed in the mine. As an interpretation of that, it is postulated that variations in shear stiffness within the shear zone contribute to the generation of high slip potential resulting in the occurrence of those seismic events. In order to justify the postulation, numerical analysis is additionally carried out, in which the shear zone is modelled with transversely isotropic models, of which shear stiffness is decreased in the same direction as a measured joint orientation in the shear zone. For source regions of those seismic events, isotropic models are used without decreasing its shear stiffness, thus resulting in the discrepancy in shear stiffness between the source regions and other areas in the shear zone. The result obtained from the analysis verifies that fault-slip potential drastically increases within the source regions due to the difference in shear stiffness. It is further found out from dynamic analysis in which fault-slip is simulated with Barton's shear strength model that the increasing slip potential is high enough to cause large seismic events in the regions. In the present study, the interpretation of seismic events occurring within a weak shear zone is provided, and a methodology to simulate high fault-slip potential that could be generated within the shear zone is developed. The methodology can be used with back analysis to determine the mechanical properties of the weak shear zone, which lead to the better estimation of fault-slip potential.

Sainoki, Atsushi; Mitri, Hani S.

2014-11-01

88

Maximum slip in earthquake fault zones, apparent stress, and stick-slip friction  

USGS Publications Warehouse

The maximum slip, observed or inferred, for a small patch within the larger fault zone of an earthquake is a remarkably well-constrained function of the seismic moment. A large set of maximum slips, mostly derived from slip models of major earthquakes, indicate that this parameter increases according to the cube root of the seismic moment. Consistent with this finding, neither the average slip rate for the patches of maximum slip nor the apparent stresses of earthquakes show any systematic dependence on seismic moment. Maximum average slip rates are several meters per second independent of moment and, for earthquakes in continental crustal settings, the apparent stress is limited to about 10 MPa. Results from stick-slip friction experiments in the laboratory, combined with information about the state of stress in the crust, can be used to predict, quite closely, the maximum slips and maximum average slip rates within the fault zones of major earthquakes as well as their apparent stresses. These findings suggest that stick-slip friction events observed in the laboratory and earthquakes in continental settings, even with large magnitudes, have similar rupture mechanisms.

McGarr, A.; Fletcher, Joe B.

2003-01-01

89

Dynamical stability of slip-stacking particles  

NASA Astrophysics Data System (ADS)

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.

Eldred, Jeffrey; Zwaska, Robert

2014-09-01

90

Electrostatic precursors to granular slip events  

PubMed Central

It has been known for over a century that electrical signals are produced by material failure, for example during crack formation of crystals and glasses, or stick-slip motion of liquid mercury on glass. We describe here new experiments revealing that slip events in cohesive powders also produce electrical signals, and remarkably these signals can appear significantly in advance of slip events. We have confirmed this effect in two different experimental systems and using two common powdered materials, and in a third experiment we have demonstrated that similar voltage signals are produced by crack-like defects in several powdered materials. PMID:22689956

Shinbrot, Troy; Kim, Nam H.; Thyagu, N. Nirmal

2012-01-01

91

Slow slip event at Kilauea Volcano  

USGS Publications Warehouse

Early in the morning of 1 February 2010 (UTC; early afternoon 31 January 2010 local time), continuous Global Positioning System (GPS) and tilt instruments detected a slow slip event (SSE) on the south flank of Kilauea volcano, Hawaii. The SSE lasted at least 36 hours and resulted in a maximum of about 3 centimeters of seaward displacement. About 10 hours after the start of the slip, a flurry of small earthquakes began (Figure 1) in an area of the south flank recognized as having been seismically active during past SSEs [Wolfe et al., 2007], suggesting that the February earthquakes were triggered by stress associated with slip [Segall et al., 2006].

Poland, Michael P.; Miklius, Asta; Wilson, J. David; Okubo, Paul G.; Montgomery-Brown, Emily; Segall, Paul; Brooks, Benjamin; Foster, James; Wolfe, Cecily; Syracuse, Ellen; Thurbe, Clifford

2010-01-01

92

Multiparameter investigation of gravitational slip  

SciTech Connect

A detailed analysis of gravitational slip, a new post-general relativity cosmological parameter characterizing the degree of departure of the laws of gravitation from general relativity on cosmological scales, is presented. This phenomenological approach assumes that cosmic acceleration is due to new gravitational effects; the amount of spacetime curvature produced per unit mass is changed in such a way that a universe containing only matter and radiation begins to accelerate as if under the influence of a cosmological constant. Changes in the law of gravitation are further manifest in the behavior of the inhomogeneous gravitational field, as reflected in the cosmic microwave background, weak lensing, and evolution of large-scale structure. The new parameter {pi}{sub 0} is naively expected to be of order unity. However, a multiparameter analysis, allowing for variation of all of the standard cosmological parameters, finds that {pi}{sub 0}=0.09{sub -0.59}{sup +0.74}(2{sigma}), where {pi}{sub 0}=0 corresponds to a cosmological constant plus cold dark matter universe under general relativity. Future probes of the cosmic microwave background (Planck) and large-scale structure (Euclid) may improve the limits by a factor of 4.

Daniel, Scott F.; Caldwell, Robert R. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Cooray, Asantha; Serra, Paolo [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Melchiorri, Alessandro [Physics Department and Sezione INFN, University of Rome, 'La Sapienza', Piazzale Aldo Moro 2, 00185 Rome (Italy)

2009-07-15

93

Ceramic joints  

DOEpatents

Butt joints between materials having different coefficients of thermal expansion are prepared having a reduced probability of failure of stress facture. This is accomplished by narrowing/tapering the material having the lower coefficient of thermal expansion in a direction away from the joint interface and not joining the narrow-tapered surface to the material having the higher coefficient of thermal expansion.

Miller, Bradley J. (Worcester, MA); Patten, Jr., Donald O. (Sterling, MA)

1991-01-01

94

7 CFR 51.491 - Wet slip.  

Code of Federal Regulations, 2010 CFR

...slip means a condition present at time of packing in which the stem scar is abnormally large, excessively wet and slippery, yields to slight...frequently accompanied by fresh radial growth cracks at the edge of the stem...

2010-01-01

95

Roughness induced boundary slip in microchannel flows  

E-print Network

Surface roughness becomes relevant if typical length scales of the system are comparable to the scale of the variations as it is the case in microfluidic setups. Here, an apparent boundary slip is often detected which can have its origin in the assumption of perfectly smooth boundaries. We investigate the problem by means of lattice Boltzmann (LB) simulations and introduce an ``effective no-slip plane'' at an intermediate position between peaks and valleys of the surface. Our simulations show good agreement with analytical results for sinusoidal boundaries, but can be extended to arbitrary geometries and experimentally obtained surface data. We find that the detected apparent slip is independent of the detailed boundary shape, but only given by the distribution of surface heights. Further, we show that the slip diverges as the amplitude of the roughness increases.

Christian Kunert; Jens Harting

2007-05-02

96

7 CFR 51.491 - Wet slip.  

Code of Federal Regulations, 2011 CFR

...Wet slip means a condition present at time of packing in which the stem scar is abnormally large, excessively wet and slippery, yields...frequently accompanied by fresh radial growth cracks at the edge of the stem...

2011-01-01

97

Slip-stream corrections performance computation  

NASA Technical Reports Server (NTRS)

This report is an analysis of experiments performed by Eiffel on the air velocity in slip stream of a propeller, and also includes a theoretical discussion of the magnitude of the velocity in different propellers.

Warner, Edward P

1920-01-01

98

Stretching Flows with General Slip Boundary Condition  

NASA Astrophysics Data System (ADS)

General slip boundary condition is used to solve the viscous incompressible flows induced by a stretching sheet. These flow problems corresponds to the planar and axisymmetric stretching. A similarity solution is developed by shooting method using Runge-Kutta algorithm. The results are graphically displayed and discussed under the influence of slip parameter and critical shear rate. The comparison of stretching flow problem subject to Navier's boundary condition in the planar case is made with the available numerical results in the literature.

Sajid, M.; Ali, N.; Abbas, Z.; Javed, T.

99

The “slip law” of the free surface  

Microsoft Academic Search

A “slip law” connects the excess velocity or “slip” of a wind-blown water surface, relative to the motion in the middle of\\u000a the mixed layer, to the wind stress, the wind-wave field, and buoyancy flux. An inner layer-outer layer model of the turbulent\\u000a shear flow in the mixed layer is appropriate, as for a turbulent boundary layer or Ekman layer

G. T. Csanady

1997-01-01

100

The slipping rib syndrome in children.  

PubMed

The slipping rib syndrome is an infrequent cause of thoracic and upper abdominal pain and is thought to arise from the inadequacy or rupture of the interchondral fibrous attachments of the anterior ribs. This disruption allows the costal cartilage tips to sublux, impinging on the intercostal nerves. Children with this entity are seldom described in the literature. We present a retrospective review of 12 children and young adults with slipping rib syndrome and a systematic approach for evaluation and treatment. PMID:11696155

Saltzman, D A; Schmitz, M L; Smith, S D; Wagner, C W; Jackson, R J; Harp, S

2001-11-01

101

Slip, Crystal Orientation, and Damage Evolution During Thermal Cycling in High-Strain Wafer-Level Chip-Scale Packages  

NASA Astrophysics Data System (ADS)

Wafer-level chip-scale package samples with pre-cross-sectioned edge rows were thermally cycled to study microstructure evolution and damage development. Electron backscattered diffraction (EBSD) and high-energy x-ray diffraction were used to obtain Sn grain orientations and the average coefficient of thermal expansion normal to the board in every joint of the package for samples in the as-fabricated and thermally cycled conditions. The results indicated a near-random distribution of joint orientation. Optical, scanning electron microscopy, and EBSD methods were used to characterize microstructure changes in pre-cross-sectioned samples due to thermal cycling. Slip trace analysis and Orientation Imaging Microscopy™ (OIM) show that slip systems with high Schmid factors (estimated global shear stress based on the package neutral point) are responsible for the observed microstructure evolution during thermal cycling, which provides information about slip systems that are more easily activated. Two joints were analyzed in detail to evaluate slip activity at different stages of their thermal history. The first case showed that a solidification twin grain boundary misorientation deviated from the twin relationship due to slip activity during thermal cycling, which can influence damage development and the path of crack propagation. The second case showed a new grain orientation developing due to gradual lattice rotation about the Sn [110] axis by a continuous recrystallization mechanism. This rotation was correlated with the operation of slip system { 110 )< {001}. Small tin whiskers emerged from the initially polished chip interface and grew with increasing thermal cycles until a crack developed in the solder that relieved the stress. As the local stresses are not known experimentally, this analysis provides observations that can be compared with a crystal plasticity model simulation.

Zhou, Bite; Zhou, Quan; Bieler, Thomas R.; Lee, Tae-kyu

2015-01-01

102

Nonlinear dynamical triggering of slow slip  

SciTech Connect

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 triggered slow-slip on the San Andreas Fault at Parkfield, CA., due to December, 2003 Mw6.5 San Simeon Earthquake (Breguier et al., Science 321, p.1478, 2008) shows very similar characteristics to what we observe in the laboratory, suggesting an extremely low in situ effective stress or a weak fault and a nonlinear-dynamical triggering mechanism.

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

103

The influence of footwear sole hardness on slip characteristics and slip-induced falls in young adults.  

PubMed

Theoretically, a shoe that provides less friction could result in a greater slip distance and foot slipping velocity, thereby increasing the likelihood of falling. The purpose of this study was to investigate the effects of sole hardness on the probability of slip-induced falls. Forty young adults were randomized into a hard or a soft sole shoe group, and tested under both nonslippery and slippery floor conditions using a motion analysis system. The proportions of fall events in the hard- and soft-soled shoe groups were not statistically different. No differences were observed between shoe groups for average slip distance, peak and average heel velocity, and center of mass slipping velocity. A strong association was found between slip distance and the fall probability. Our results demonstrate that the probability of a slip-induced fall was not influenced by shoe hardness. Once a slip is induced, slip distance was the primary predictor of a slip-induced fall. PMID:23062013

Tsai, Yi-Ju; Powers, Christopher M

2013-01-01

104

Prediction of slips: an evaluation of utilized coefficient of friction and available slip resistance  

Microsoft Academic Search

The purpose of this study was to investigate the relationship between measures of floor surface slip resistance and an individual's peak utilized coefficient of friction (COFU) on the probability of a slip occurring during level walking. Video, kinematic and ground reaction force data were recorded simultaneously as subjects walked at a self-selected speed during conditions of normal and reduced floor

J. M. Burnfield; C. M. Powers

2006-01-01

105

SYNTHESIS OF ORGANIC EPOXIDES USING A SPINNING TUBE-IN-TUBE REACTOR  

EPA Science Inventory

The U.S. Environmental Protectiion Agency (USEPA) and Kreido Laboratories have established a Cooperative Research and Development Agreement (CRADA) collaboration, to develop and commercialize green and sustainable chemistries in the area of industrial chemcial synthesis. The STT...

106

GREEN REACTION CHEMISTRIES PERFORMED IN THE SPINNING TUBE-IN-TUBE (STT) REACTOR  

EPA Science Inventory

The U. S. Environmental Protection Agency (USEPA) and Kreido Laboratories have established a Cooperative Research and Development Agreement (CRADA) collaboration, to develop and commercialize green and sustainable chemistries in the area of industrial chemical synthesis. Utilizi...

107

PROCESS INTENSIFIED GREEN REACTION CHEMISTRIES PERFORMED IN THE SPINNING TUBE-IN-TUBE (STT®) REACTOR  

EPA Science Inventory

The U. S. Environmental Protection Agency (USEPA) and Kreido Laboratories have established a Cooperative Research and Development Agreement (CRADA) collaboration, to develop and commercialize green and sustainable chemistries in the area of industrial chemical synthesis. Utilizi...

108

Organic Synthesis in a Spinning Tube-in-Tube (STT¢) Reactor  

EPA Science Inventory

Continuous-flow reactors have been designed to minimize and potentially overcome the limitations of heat and mass transfer that are encountered in chemical reactors and further experienced upon scale up of a reaction. With process intensification, optimization of the reaction i...

109

Human mismatch repair protein hMutL? is required to repair short slipped-DNAs of trinucleotide repeats.  

PubMed

Mismatch repair (MMR) is required for proper maintenance of the genome by protecting against mutations. The mismatch repair system has also been implicated as a driver of certain mutations, including disease-associated trinucleotide repeat instability. We recently revealed a requirement of hMutS? in the repair of short slip-outs containing a single CTG repeat unit (1). The involvement of other MMR proteins in short trinucleotide repeat slip-out repair is unknown. Here we show that hMutL? is required for the highly efficient in vitro repair of single CTG repeat slip-outs, to the same degree as hMutS?. HEK293T cell extracts, deficient in hMLH1, are unable to process single-repeat slip-outs, but are functional when complemented with hMutL?. The MMR-deficient hMLH1 mutant, T117M, which has a point mutation proximal to the ATP-binding domain, is defective in slip-out repair, further supporting a requirement for hMLH1 in the processing of short slip-outs and possibly the involvement of hMHL1 ATPase activity. Extracts of hPMS2-deficient HEC-1-A cells, which express hMLH1, hMLH3, and hPMS1, are only functional when complemented with hMutL?, indicating that neither hMutL? nor hMutL? is sufficient to repair short slip-outs. The resolution of clustered short slip-outs, which are poorly repaired, was partially dependent upon a functional hMutL?. The joint involvement of hMutS? and hMutL? suggests that repeat instability may be the result of aberrant outcomes of repair attempts. PMID:23086927

Panigrahi, Gagan B; Slean, Meghan M; Simard, Jodie P; Pearson, Christopher E

2012-12-01

110

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

NASA Astrophysics Data System (ADS)

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 ˜2500-5200 yr for past earthquakes along the different segments of the western Bogd Fault. This suggests that the three western segments of the Bogd Fault and the Gurvan Bulag thrust fault (a reverse fault bounding the southern side of the Ih Bogd range that ruptured during the 1957 earthquake) have similar average recurrence times, and therefore may have ruptured together in previous earthquakes as they did in 1957. These results suggest that the western part of the Bogd Fault system, including the Gurvan Bulag thrust fault, usually behaves in a 'characteristic earthquake' mode.

Rizza, M.; Ritz, J.-F.; Braucher, R.; Vassallo, R.; Prentice, C.; Mahan, S.; McGill, S.; Chauvet, A.; Marco, S.; Todbileg, M.; Demberel, S.; Bourlès, D.

2011-09-01

111

Inertial aided cycle slip detection and identification for integrated PPP GPS and INS.  

PubMed

The recently developed integrated Precise Point Positioning (PPP) GPS/INS system can be useful to many applications, such as UAV navigation systems, land vehicle/machine automation and mobile mapping systems. Since carrier phase measurements are the primary observables in PPP GPS, cycle slips, which often occur due to high dynamics, signal obstructions and low satellite elevation, must be detected and repaired in order to ensure the navigation performance. In this research, a new algorithm of cycle slip detection and identification has been developed. With the aiding from INS, the proposed method jointly uses WL and EWL phase combinations to uniquely determine cycle slips in the L1 and L2 frequencies. To verify the efficiency of the algorithm, both tactical-grade and consumer-grade IMUs are tested by using a real dataset collected from two field tests. The results indicate that the proposed algorithm can efficiently detect and identify the cycle slips and subsequently improve the navigation performance of the integrated system. PMID:23202164

Du, Shuang; Gao, Yang

2012-01-01

112

Inertial Aided Cycle Slip Detection and Identification for Integrated PPP GPS and INS  

PubMed Central

The recently developed integrated Precise Point Positioning (PPP) GPS/INS system can be useful to many applications, such as UAV navigation systems, land vehicle/machine automation and mobile mapping systems. Since carrier phase measurements are the primary observables in PPP GPS, cycle slips, which often occur due to high dynamics, signal obstructions and low satellite elevation, must be detected and repaired in order to ensure the navigation performance. In this research, a new algorithm of cycle slip detection and identification has been developed. With the aiding from INS, the proposed method jointly uses WL and EWL phase combinations to uniquely determine cycle slips in the L1 and L2 frequencies. To verify the efficiency of the algorithm, both tactical-grade and consumer-grade IMUs are tested by using a real dataset collected from two field tests. The results indicate that the proposed algorithm can efficiently detect and identify the cycle slips and subsequently improve the navigation performance of the integrated system. PMID:23202164

Du, Shuang; Gao, Yang

2012-01-01

113

Quake clamps down on slow slip  

NASA Astrophysics Data System (ADS)

continuous GPS (cGPS) data from the Hikurangi subduction zone in New Zealand, we show for the first time that stress changes induced by a local earthquake can arrest an ongoing slow slip event (SSE). The cGPS data show that the slip rate in the northern portion of the 2013/2014 Kapiti SSE decreased abruptly following a nearby intraslab earthquake. We suggest that deceleration of the Kapiti SSE in early 2014 occurred due to a tenfold increase in the normal stress relative to shear stress in the SSE source, induced by the nearby Mw 6.3 earthquake, consistent with expectations of rate and state friction. Our observation of an abrupt halting/slowing of the SSE in response to stress changes imposed by a local earthquake has implications for the strength of fault zones hosting SSEs and supports the premise that static stress changes are an important ingredient in triggering (or delaying) fault slip.

Wallace, Laura M.; Bartlow, Noel; Hamling, Ian; Fry, Bill

2014-12-01

114

Seven big strike-slip earthquakes  

NASA Astrophysics Data System (ADS)

We examine seven large (Mw > 7) strike-slip earthquakes that occurred since the beginning of ERS 1 and 2 missions. We invert GPS observations and InSAR interferograms and azimuth offsets for coseismic slip distributions. We explore two refinements to the traditional least-squares inversion technique with roughness constraints. First, we diverge from the usual definition of ``roughness'' as the average roughness over the entire fault plane, and allow ``variable smoothing'' constraints. Variable smoothing allows our inversion to select models that are more complex in regions that are well-resolved by the data, while still damping regions that are poorly resolved. Second, we choose our smoothing parameters using the jR_i criterion. The jR_i criterion draws on the theory behind cross-validation and the bootstrap method. We examine the theoretical basis behind such methods and use an analytical approximation technique for linear problems. We provide maps of model variance and spatial averaging scale over the fault plane, to explicitly show which features in our slip models are robust. We examine the 1992 Landers (CA), 1995 Sakhalin (Russia), 1995 Kobe (Japan), 1997 Ardekul (Iran), 1997 Manyi (Tibet), 1999 Hector Mine (CA), and 2001 Kunlun (Tibet) earthquakes. We compare features of the slip distributions such as the depth distribution of slip, the inferred magnitude and the degree of heterogeneity of slip over the fault plane, as resolved by the available InSAR and GPS data. We end with a brief description of the data coverage required for future earthquakes of similar size if we want to infer some of the above quantities to within a given confidence interval. We describe both the number of InSAR scenes and the distribution of GPS points that would be required, based on theoretical treatments of the fault plane/data point geometry using the jR_i method.

Lohman, R. B.; Simons, M.; Pritchard, M. E.

2003-12-01

115

Slipping processes in residual badlands reliefs  

NASA Astrophysics Data System (ADS)

We define slips as structures developed by more or less saturated colloidal suspension that slide down the walls of residual reliefs found in badlands. These suspensions seem to originate in the soils crowning gully reliefs and also from rainwater dripping onto the walls of poorly cemented sediments such as siltstone. We call this process slipping and the resulting morphologies represent a group of minor badlands forms, often linked to piping and fluting. Slipping occurs according to the following sequence of forms: 1. Mud droplets. These are irregular linear structures caused by mud droplets sliding down sub-vertical walls. The droplet is usually found at the end of a small channel. These morphologies represent the course of the sliding droplets that become fossilized and not the impact of the droplets on the sediment. 2. Slips sensu stricto. These are uninterrupted surface structures covering sub-vertical walls to a greater or lesser extent. The thickness of this type of covering varies from a few millimetres to 5cm. The inner structure of the slips consists of small laminas (» 100mm) and on the exterior they often present drip channels. A special case of these forms is butterfly structures, which appear in isolation, with repetitive patterns and the appearance of a winged insect stuck to the wall. 3. Pseudo-stalactites. These are free-standing conical regrowths with some similarity to stalactites in a karst cave. They occur when slips grow to over 5cm thick. The growth of these forms is similar to that of slips, with external superposition of fine, concentric layers with no central pore. A variety of these pseudo-stalactites are nodulous stalactites whose genesis is unknown. In this context, we should mention the existence of occasional stalagmites. In other cases, curtains of pseudo-stalactites can be found where these patterns are repeated finely. A more evolved stage of this form is the coalescence of pseudo-stalactites, representing a massive advance of this process. Pseudo-stalactites are normally found as vertical, but occasionally they lean, indicating movement of unstable blocks. The process can present recycling when some of the forms described become detached and fall. This is more likely on poorly sheltered surfaces, exposed to wind and the direct impact of rain and frost. All forms of slips suggests that these morphologies depend on the varying characteristics of the colloidal suspensions causing them, and constitute intermediate stages in the retention of sediments from erosion, which are very different to the alluvial sediments stored in the drainage network.

Díaz-Hernández, Jose Luis; Yepes, Jorge

2010-05-01

116

A STUDY ON HIGH STRENGTH BOLTED JOINT WITH METAL-SPRAYED CONTACT SURFACES  

NASA Astrophysics Data System (ADS)

Slip coefficient of high-strength bolt friction joints is well known to depend on the condition of contact surfaces. The coefficient is determined as 0.4 in the Specifications for Highway Bridges and the Design Standards for Railway Structures and Commentary (Steel Structures) in Japan, in the condition of roughened contact surfaces with mill scale removed or painted contact surfaces with inorganic zinc rich paint. However, the slip coefficient with metal-sprayed surfaces is not clear. For the joints with metalsprayed surfaces, hot-dip galvanized bolts are applied and such bolts are tightened by turn-of-nut method. However, it is unclear how much axial force is induced into the bolts in the joints with metal-sprayed surfaces. In order to examine slip coefficient of the bolted joints with metal-sprayed contact surfaces slip tests of high strength bolted joints were carried out. On the basis of above examinations, the slip coefficient with metal-sprayed surfaces is proposed in this paper. To clarify the induced axial force of the bolts, bolt-tightening tests were carried out. Considering bolt diameter, bolt length, induced axial forces and their relaxation, nut rotation angles are proposed in relation to different bolt size.

Minami, Kuniaki; Saito, Masamichi; Yokoyama, Hideki; Sugimoto, Ichiro; Nojima, Takao; Masunaga, Toshihiko; Nagasaki, Eiji

117

State variable fault constitutive relations for dynamic slip  

NASA Astrophysics Data System (ADS)

Laboratory observations of quasistatic rock-on-rock frictional sliding have led to the development of fault constitutive relations which incorporate effects of slip rate and slip history, or state, on frictional resistance. These friction models can be constructed to predict sliding behavior which resembles slip weakening. Local, high-frequency records of fault displacements and shear stresses have been recorded during stick-slip failures on a simulated fault in a block of Sierra granite. These observations suggest that, despite the vastly different slip conditions which characterize quasistatic sliding and stick-slip, the same constitutive friction models might also adequately describe the frictional response of the simulated fault under dynamic, seismogenic slip conditions. The maximum observed slip speeds during stick-slip are roughly three or four orders of magnitude larger than speeds used in quasistatic tests. In addition, the velocity jumps observed during stick-slip are as much as six orders of magnitude larger than those which typify the quasistatic tests. Fault behavior which is slip weakening-like in appearance is observed during stick-slip. Immediately prior to the onset of stick-slip sliding, rapid increases in local shear stresses, from initial shear stress levels to peak shear stress levels, are observed. Following the onset of stick-slip sliding, shear stresses on the fault rapidly decrease from their peak levels to lower residual sliding stress levels. In general, the stress drops observed during stick-slip are approximately 10% of the average applied shear stresses. Stress changes are compared to calculations based on two specific constitutive friction models which are interchangeable at low slip rates but predict markedly different results for high rates of slip. Both quasistatic and dynamic fault slip behavior are accounted for by the rate- and state-dependent friction model, but the stick-slip data suggest that an appropriate fault constitutive relation must admit high-speed cutoffs to the velocity-dependent effects. The cutoffs impose bounds on the changes in fault frictional strength during unstable slip, with limiting shear stresses determined by normal stress and fault loading history as well as friction model parameters. Finally, the existence of these cutoffs implies that fault weakening at the onset of stick-slip is essentially slip rate-independent so that the process resembles slip weakening.

Okubo, Paul G.; Dieterich, James H.

118

Joint Projects / Joint Seminars October 2013  

E-print Network

Joint Projects / Joint Seminars October 2013 Information Sheet Bilateral Programs (MoU) ­ Joint Projects (JP) / Joint Seminars (JS) FWF has signed bilateral agreements ­ so called "Memorandums of Understanding" (MoU) ­ with several international partner organisations. These agreements usually aim at jointly

Fuchs, Clemens

119

What do formal inversions of space geodetic data tell us about fault slip rates? Examples from Southern California. (Invited)  

NASA Astrophysics Data System (ADS)

We use secular velocities from the continuous GPS data provided by the Plate Boundary Observatory (PBO) and Scripps Orbit Permanent Array Center (SOPAC), campaign GPS data (SCEC Crustal Motion Model) and InSAR data from the ERS-1/2 and ENVISAT satellites spanning nearly 20 years (1992-2010) to estimate the contemporaneous slip rates and locking depths on the Southern San Andreas fault (SAF), the San Jacinto fault (SJF) and the Elsinore fault. The model parameter space was interrogated using a Gibbs sampler, a Markov chain Monte Carlo algorithm which naturally approximates the joint probability distribution for the model parameters and allows for a formal evaluation of model uncertainties and trade-offs. We performed joint inversions of all available space geodetic data using the Savage and Burford (1973) dislocation model. Previous geodetic estimates of slip rates in this region based on dislocation models have generally inferred a higher slip velocity on the SAF (21-26 mm/yr), and a lower velocity on the SJF (12-19 mm/yr) (Becker et al. 2005, Fay and Humphreys 2005, Meade and Hager 2005, Fialko 2006). These "geodetic" slip rates are generally higher than geologic estimates representing average slip rates on time scales of 10^4-10^6 years. We investigate implications of fault geometry such as a non-vertical SAF and a "blind" segment of the SJF (Fialko 2006; Lin et al. 2007). Using the fault geometry motivated by these recent studies, we estimate a slip rate of 16(+/-2) mm/yr for the southern SAF, and a combined slip rate of 21(+/-3) mm/yr for the two closely spaced branches of the southern San Jacinto fault (the Coyote Creek fault and the blind southern continuation of the Clark fault). The locking depths are estimated at 7(+/-3) km and 14(+/-6) km for the SAF and SJF, respectively. For the SJF, we note a significant trade-off between fault velocity and locking depth, with the best-fitting values occurring at the lower end of the formally estimated parameter ranges: 19 mm/yr and 11 km, respectively. We also investigate the effect of elastic heterogeneities on the preferred fault slip rate and locking depth. We use the elastic structure inferred from seismic body wave tomography. The forward model incorporating the effects of elastic heterogeneities is based on the fictitious body force technique of Barbot et al. (2009). As the steady-state interseismic velocity field is computed using a superposition of "seismic" slip in the upper crust and the rigid block motion, these calculations are also relevant for coseismic deformation in heterogeneous elastic media.

Lindsey, E. O.; Fialko, Y.

2010-12-01

120

Ground Displacement by Strike-Slip Motion  

NSDL National Science Digital Library

This photograph illustrates strike-slip motion along a fault trace. The section of fence in the foreground has been offset 8.5 feet to the left relative to the segment in the background. The displacement occured in a rural area near Woodville, California, as a result of the San Francisco Earthquake on April 18, 1906.

121

Slip casting and nitridation of silicon powder  

NASA Technical Reports Server (NTRS)

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.

Seiko, Y.

1985-01-01

122

Phase-slip centers and their interactions  

NASA Astrophysics Data System (ADS)

The author performed a series of different experiments in order to measure the diffusion length of the quasiparticle charge generated in a phase-slip center (PSC) and to detect the oscillations of the supercurrent in the PSC. Three different types of samples were fabricated photolithographically: samples of type S, samples of type T and samples of type M.

Aponte, J. M.

1983-06-01

123

Avoiding stick-slip through PD control  

Microsoft Academic Search

Addresses the question of how to achieve steady motion at very low velocities using proportional-derivative (PD) control. Most prior work in control has used friction models which depend only on the current value of velocity. This type of analysis indicates that stick-slip can be avoided only through velocity feedback. The tribology literature, however, indicates that friction also depends on the

Pierre E. Dupont

1994-01-01

124

Joint Problems  

MedlinePLUS

... shoulder joint. About 30% of older people have tears in their rotator cuff muscles and tendons, but many have no symptoms. Carpal tunnel syndrome is pressure on a nerve in the wrist and may cause tingling, numbness and pain in the hand. It ... Updated: March 2012 Posted: March 2012

125

Constraining fault constitutive behavior with slip and stress heterogeneity  

E-print Network

Constraining fault constitutive behavior with slip and stress heterogeneity B. T. Aagaard1 and T. H and postshear stress on a fault can be used to constrain fault constitutive behavior beyond that required on a vertical, planar strike-slip fault show that the conditions that lead to slip heterogeneity remain in place

Greer, Julia R.

126

Pivoting and slip in an angular contact bearing  

NASA Technical Reports Server (NTRS)

Pivoting slips are calculated for the ball-race and ball-ball contacts in a retainerless bearing. The calculation is kinematic, ignoring all inertial loadings. Pure spin and uniform precession of the balls are considered. Pivoting slip magnitudes are compared with several other kinds of slip which were previously reported in an R4 size bearing.

Kingsbury, E.

1983-01-01

127

Studies on Slip in Fe2%V Alloy Single Crystals  

Microsoft Academic Search

In an attempt to measure the critical resolved shear stress for slip of bcc metals, Fe-2%V single crystals were compressed along [110] direction, constraining the side faces, (001) and (00\\\\bar{1}), with a pair of fixed walls. Under these conditions, all slips are geometrically expected to be suppressed, and consequently [100] or [010] slip will be activated. Electron microscope study on

Shin Takeuchi

1969-01-01

128

Downscaling of slip distribution for strong earthquakes  

NASA Astrophysics Data System (ADS)

We intend to develop a downscaling model to enhance the earthquake slip distribution resolution. Slip distributions have been obtained by other researchers using various inversion methods. As a downscaling model, we are discussing fractal models that include mono-fractal models (fractional Brownian motion, fBm; fractional Lévy motion, fLm) and multi-fractal models as candidates. Log - log-linearity of k (wave number) versus E (k) (power spectrum) is the necessary condition for fractality: the slip distribution is expected to satisfy log - log-linearity described above if we can apply fractal model to a slip distribution as a downscaling model. Therefore, we conducted spectrum analyses using slip distributions of 11 earthquakes as explained below. 1) Spectrum analyses using one-dimensional slip distributions (strike direction) were conducted. 2) Averaging of some results of power spectrum (dip direction) was conducted. Results show that, from the viewpoint of log - log-linearity, applying a fractal model to slip distributions can be inferred as valid. We adopt the filtering method after Lavallée (2008) to generate fBm/ fLm. In that method, generated white noises (random numbers) are filtered using a power law type filter (log - log-linearity of the spectrum). Lavallée (2008) described that Lévy white noise that generates fLm is more appropriate than the Gaussian white noise which generates fBm. In addition, if the 'alpha' parameter of the Lévy law, which governs the degree of attenuation of tails of the probability distribution, is 2.0, then the Lévy distribution is equivalent to the Gauss distribution. We analyzed slip distributions of 11 earthquakes: the Tohoku earthquake (Wei et al., 2011), Haiti earthquake (Sladen, 2010), Simeulue earthquake (Sladen, 2008), eastern Sichuan earthquake (Sladen, 2008), Peru earthquake (Konca, 2007), Tocopilla earthquake (Sladen, 2007), Kuril earthquake (Sladen, 2007), Benkulu earthquake (Konca, 2007), and southern Java earthquake (Konca, 2006)). We obtained the following results. 1) Log - log-linearity (slope of the linear relationship is ' - ?') of k versus E(k) holds for all earthquakes. 2) For example, ? = 3.70 and ? = 1.96 for the Tohoku earthquake (2011) and ? = 4.16 and ? = 2.00 for the Haiti earthquake (2010). For these cases, the Gauss' law is appropriate because alpha is almost 2.00. 3) However, ? = 5.25 and ? = 1.25 for the Peru earthquake (2007) and ? = 2.24 and ? = 1.57 for the Simeulue earthquake (2008). For these earthquakes, the Lévy law is more appropriate because ? is far from 2.0. 4) Although Lavallée (2003, 2008) concluded that the Lévy law is more appropriate than the Gauss' law for white noise, which is later filtered, our results show that the Gauss law is appropriate for some earthquakes. Lavallée and Archuleta, 2003, Stochastic modeling of slip spatial complexities for the 1979 Imperial Valley, California, earthquake, GEOPHYSICAL RESEARCH LETTERS, 30(5). Lavallée, 2008, On the random nature of earthquake source and ground motion: A unified theory, ADVANCES IN GEOPHYSICS, 50, Chap 16.

Yoshida, T.; Oya, S.; Kuzuha, Y.

2013-12-01

129

Spatiotemporal evolution of seismic and aseismic slip on the Longitudinal Valley Fault, Taiwan  

NASA Astrophysics Data System (ADS)

The Longitudinal Valley Fault (LVF) in eastern Taiwan is a high slip rate fault (about 5 cm/yr), which exhibits both seismic and aseismic slip. Deformation of anthropogenic features shows that aseismic creep accounts for a significant fraction of fault slip near the surface, whereas a fraction of the slip is also seismic, since this fault has produced large earthquakes with five Mw>6.8 events in 1951 and 2003. In this study, we analyze a dense set of geodetic and seismological data around the LVF, including campaign mode Global Positioning System(GPS) measurements, time series of daily solutions for continuous GPS stations (cGPS), leveling data, and accelerometric records of the 2003 Chenkung earthquake. To enhance the spatial resolution provided by these data, we complement them with interferometric synthetic aperture radar (InSAR) measurements produced from a series of Advanced Land Observing Satellite images processed using a persistent scatterer technique. The combined data set covers the entire LVF and spans the period from 1992 to 2010. We invert this data to infer the temporal evolution of fault slip at depth using the Principal Component Analysis-based Inversion Method. This technique allows the joint inversion of diverse data, taking the advantage of the spatial resolution given by the InSAR measurements and the temporal resolution afforded by the cGPS data. We find that (1) seismic slip during the 2003 Chengkung earthquake occurred on a fault patch which had remained partially locked in the interseismic period, (2) the seismic rupture propagated partially into a zone of shallow aseismic interseismic creep but failed to reach the surface, and (3) that aseismic afterslip occurred around the area that ruptured seismically. We find consistency between geodetic and seismological constraints on the partitioning between seismic and aseismic creep. About 80-90% of slip on the southern section of LVF in the 0-26 km, seismogenic depth range, is actually aseismic. We infer that the clay-rich Lichi Mélange is the key factor promoting aseismic creep at shallow depth.

Thomas, Marion Y.; Avouac, Jean-Philippe; Champenois, Johann; Lee, Jian-Cheng; Kuo, Long-Chen

2014-06-01

130

Effects of slip, slip rate, and shear heating on the friction of granite  

USGS Publications Warehouse

The stability of fault slip is sensitive to the way in which frictional strength responds to changes in slip rate and in particular to the effective velocity dependence of steady state friction ????ss/?? ln V. This quantity can vary substantially with displacement, temperature and slip rate. To investigate the physical basis for this behavior and the possible influence of shear heating, we slid initially bare granite surfaces in unconfined rotary shear to displacements of hundreds of millimeters at normal stresses, ??n, of 10 and 25 MPa and at room temperature. We imposed step changes in slip rate within the range 10-2 to 103.5 ??m/s and also monitored frictional heating with thermistors embedded in the granite. The transient response of ?? to slip rate steps was fit to a rate- and state-dependent friction law using two state variables to estimate the values of several parameters in the constitutive law. The first 20 mm of slip shows rising friction and falling ????ss/?? ln V; further slip shows roughly constant friction, ????ss/?? ln V and parameter values, suggesting that a steady state condition is reached on the fault surface. At V ??? 10 ??m/s, ????ss/?? ln V = -0.004 ?? 0.001. At higher rates the response is sensitive to normal stress: At ??n = 25 MPa granite shows a transition to effective velocity strengthening (????ss/?? ln V = 0.008 ?? 0.004) at the highest slip rates tested. At 10 MPa granite shows a less dramatic change to ????ss/?? ln V ??? 0 at the highest rates. The maximum temperature measured in the granite is ???60??C at 25 MPa and 103.5 ??m/s. Temperatures are in general agreement with a numerical model of heat conduction which assumes spatially homogeneous frictional heating over the sliding surface. The simplest interpretation of our measurements of ????ss/?? ln V is that the granite is inherently veocity weakening (?????ss/??? In V 0 mimics velocity strengthening. These results have implications for the frictional behavior of faults during earthquakes. High slip rates may cause a switch to effective velocity strengthening which could limit peak coseismic slip rate and stress drop. For fluid-saturated faults, strengthening by this mechanism may be partly or fully offset by weakening due to thermal pressurization of a poorly drained pore fluid.

Blanpied, M.L.; Tullis, T.E.; Weeks, J.D.

1998-01-01

131

The effect of sliding velocity on the mechanical response of an artificial joint in Topopah Spring Member tuff; Yucca Mountain Site Characterization Project  

SciTech Connect

A smooth artificial joint in Topopah Spring Member tuff was sheared at constant normal stress at velocities from 0 to 100 {mu}m/s to determine the velocity-dependence of shear strength. Two different initial conditions were used: (1) unprimed -- the joint had been shear stress-free since last application of normal stress, and before renewed shear loading; and (2) primed -- the joint had undergone a slip history after application of normal stress, but before the current shear loading. Observed steady-state rate effects were found to be about 3 times lager than for some other silicate rocks. These different initial conditions affected the character of the stress-slip curve immediately after the onset of slip. Priming the joint causes a peak in the stress-slip response followed by a transient decay to the steady-state stress, i.e., slip weakening. Slide-hold-slide tests exhibit time-dependent strengthening. When the joint was subjected to constant shear stress, no slip was observed; that is, joint creep did not occur. One set of rate data was collected from a surface submerged in tap water, the friction was higher for this surface, but the rate sensitivity was the same as that for surfaces tested in the air-dry condition.

Olsson, W.A.

1994-04-01

132

On the mechanism of cross slip in Ni3Al  

NASA Technical Reports Server (NTRS)

The mechanical properties of L1(2) intermetallic alloys have been previously described by models based on the assumption that cube cross slip is the rate-limiting step. In this study, it was demonstrated that the cube cross-slip event must be reversible under a change in loading direction. This observation allows the cross-slip models to remain consistent with cyclic deformation data. Additionally, this observation was used as a critical test of the available cross-slip models. It was demonstrated that the rate-limiting step cannot be a total cross-slip event, in which both a/2 110-line superpartial dislocations cross slip to the cube plane. Conversely, the limited cross-slip event proposed by Paidar et al. (1984), was demonstrated to be consistent with the reversibility constraint. This lends additional experimental support to this model.

Milligan, Walter W.; Antolovich, Stephen D.

1989-01-01

133

Phase Slips in Oscillatory Hair Bundles  

NASA Astrophysics Data System (ADS)

Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production.

Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

2013-04-01

134

Smectite-illite transition during coseismic slip  

NASA Astrophysics Data System (ADS)

Few evidences for coseismic slip events are preserved in natural fault rocks except pseudotachylytes showing a clear evidence of melting caused by frictional shear at high slip rates [e.g., Spray, 1987; Tsutsumi and Shimamoto, 1997; Hirose and Shimamoto, 2005]. Higher maturity of vitrinite of coal fragments is observed in the fault cores recovered from the Nankai accretionary prism [Sakaguchi eta al., 2011], and also in the friction experiments sheared at seismic slip rates [Kitamura et al., 2012], implying that local heating is caused by frictional shear during earthquakes. Another possible evidence for coseismic slip is illitization of smectite clay along faults observed in the present and ancient accretionary prisms [Yamaguchi et al., 2011; Kameda et al., 2013]. Kameda et al. [2013] have estimated the fault activity using the kinetics of smectite-illite transition, which is determined in the studies on long-term diagenetic processes of smectite-illite transition and may not be appropriate for the short-tem reaction caused by frictional heating associated with coseismic slip. Here we report on high-speed friction experiments on synthetic smectite-quartz mixtures. The goals of our experiments are: (1) to reproduce the illitization of smectite clay (Na-montmorillonite) during coseismic shear and (2) to obtain better kinetic parameters to estimate the fault activity of coseismic slip. The friction experiments were conducted on the rotary-shear apparatus at AIST. One gram of the synthetic gouge of smectite-quartz (70:30 wt.%) mixture was sheared at slip velocity of 1.3 m/s, normal stress of 1 MPa, and up to displacement of 55 m. Because cation exchange between sodium ion in smectite and potassium ion in fluid is required for the illitization, we used gouge samples dampened with two different pore fluid media: (1) 1 mol/L aqueous solution of potassium chloride (KCl) and (2) pure water. Friction coefficient of the gouge sheared with potassium rich fluid is 0.45 at peak and 0.12 at steady state, and approximately two times greater than friction coefficient of the gouge sheared with pure water (0.27 at peak and 0.05 at steady state). Pore fluid chemistry largely affects the frictional strength of gouge and thus probably temperature evolution within the gouge. X-ray diffraction analysis of the post-experiment gouges with ethylene glycol treatment indicate illite generation in the gouge sheared with potassium-rich fluid; i.e., smectite is partly transformed to illite by the frictional heating. The gouge sheared with pure water, on the other hand, shows no evidence for illite generation. We will present more experimental results and derive interrelationships between the degree of the illitization, slip velocity, shear displacement, frictional strength, temperature, and concentrations of the potassium ion in pore fluid.

Takahashi, M.; Kitajima, H.

2013-12-01

135

Modeling of rock friction 2. Simulation of preseismic slip  

USGS Publications Warehouse

The constitutive relations developed in the companion paper are used to model detailed observations of preseismic slip and the onset of unstable slip in biaxial laboratory experiments. The simulations employ a deterministic plane strain finite element model to represent the interactions both within the sliding blocks and between the blocks and the loading apparatus. Both experiments and simulations show that preseismic slip is controlled by initial inhomogeneity of shear stress along the sliding surface relative to the frictional strength. As a consequence of the inhomogeneity, stable slip begins at a point on the surface and the area of slip slowly expands as the external loading increases. A previously proposed correlation between accelerating rates of stable slip and growth of the area of slip is supported by the simulations. In the simulations and in the experiments, unstable slip occurs shortly after a propagating slip event traverses the sliding surface and breaks out at the ends of the sample. In the model the breakout of stable slip causes a sudden acceleration of slip rates. Because of velocity dependency of the constitutive relationship for friction, the rapid acceleration of slip causes a decrease in frictional strength. Instability occurs when the frictional strength decreases with displacement at a rate that exceeds the intrinsic unloading characteristics of the sample and test machine. A simple slider-spring model that does not consider preseismic slip appears to approximate the transition adequately from stable sliding to unstable slip as a function of normal stress, machine stiffness, and surface roughness for small samples. However, for large samples and for natural faults the simulations suggest that the simple model may be inaccurate because it does not take into account potentially large preseismic displacements that will alter the friction parameters prior to instability. Copyright ?? 1979 by the American Geophysical Union.

Dieterich, J.H.

1979-01-01

136

Gaseous slip flow in long microchannels  

Microsoft Academic Search

An analytic and experimental investigation into gaseous flow with slight rarefaction through long microchannels is undertaken. A two-dimensional (2-D) analysis of the Navier-Stokes equations with a first-order slip-velocity boundary condition demonstrates that both compressibility and rarefied effects are present in long microchannels. By undertaking a perturbation expansion in ?, the height-to-length ratio of the channel, and using the ideal gas

Errol B. Arkilic; Martin A. Schmidt; Kenneth S. Breuer

1997-01-01

137

Apparent fluid slip at hydrophobic microchannel walls  

Microsoft Academic Search

Micron-resolution particle image velocimetry is used to measure the velocity profiles of water flowing through 30×300 mum channels. The velocity profiles are measured to within 450 nm of the microchannel surface. When the surface is hydrophilic (uncoated glass), the measured velocity profiles are consistent with solutions of Stokes' equation and the well-accepted no-slip boundary condition. However, when the microchannel surface

Derek C. Tretheway; Carl D. Meinhart

2002-01-01

138

Apparent fluid slip at hydrophobic microchannel walls  

Microsoft Academic Search

Micron-resolution particle image velocimetry is used to measure the velocity profiles of water flowing through 30×300 ?m channels. The velocity profiles are measured to within 450 nm of the microchannel surface. When the surface is hydrophilic (uncoated glass), the measured velocity profiles are consistent with solutions of Stokes’ equation and the well-accepted no-slip boundary condition. However, when the microchannel surface

Derek C. Tretheway; Carl D. Meinhart

2002-01-01

139

Analysis of Slip Flow in Microchannels  

Microsoft Academic Search

Since the surface to volume ratio in enclosed flow devices scales as L-1 , the small length scale associated with micro-devices dictates the importance of boundary conditions. Several researchers have suggested that the well-accepted no-slip boundary condition may not be suitable for flows at the micro - and nano-scale (Zhu and Granik, 2001; Ruckenstein & Rajora, 1983; Barrat & Bocquet,

Derek C. Tretheway; Xiaojun Liu; Carl D. Meinhart

140

Surgical treatment of the 'slipping rib syndrome'.  

PubMed

This review seeks to draw attention to the existence of the 'slipping rib syndrome' as a not uncommon clinical entity. It is characterized by trunk pain in a radicular distribution, often related to certain movements or activity, but not associated with other visceral symptoms. The diagnosis is a clinical one, with surgical excision of the affected rib and costal cartilage a successful simple treatment for relieving those patients of a severe and persistent pain syndrome. PMID:6733425

Copeland, G P; Machin, D G; Shennan, J M

1984-07-01

141

Quantum phase slips in superconducting nanowires  

NASA Astrophysics Data System (ADS)

In this thesis we present the results of an experimental study of the superconducting transitions of ultrathin nanowires. In order to reliably fabricate homogeneous nanowires, a novel technique was developed. By depositing 4--5 nm of amorphous Mo79Ge21 on carbon nanotubes or ropes, which act as mechanical substrates, we are able to routinely fabricate wires about 10 nm in diameter. More than 20 nanowires have been fabricated and measured, with lengths ranging from 150 nm to 1mum, and nominal widths ranging from 10 to 22 nm. Our resistance-temperature measurements of these nanowires display superconducting transitions which broaden with decreasing cross-sectional areas; the thinnest wires' resistance stayed almost constant down to 1.5K. Since resistance arises from phase slippage in the superconducting order parameter Psi, such resistive transitions can be explained by a combination of the activation of phase slips through a free energy barrier via thermal excitation close to TC, and via macroscopic quantum tunneling at lower temperatures. Because the phase slip rates increase exponentially with decreasing cross-sectional areas of the wires, superconductivity in a thin wire is suppressed at low temperatures by the proliferation of quantum phase slips. This conclusion is based on the quantitative agreement between the data and the predictions made by a microscopic theory developed by Golubev and Zaikin.

Lau, Chun Ning

142

Progressive slippage after pinning for slipped capital femoral epiphysis.  

PubMed

The authors retrospectively reviewed seven cases of progressive slipped capital femoral epiphysis after screw fixation. All seven patients initially presented with chronic symptoms, and five had an acute exacerbation of symptoms with the appearance of an acute-on-chronic slip. Of the other two, one had obvious motion at the proximal femoral physis and the other had increased symptoms but did not have an obvious acute slip radiographically. All underwent percutaneous screw fixation. In four patients a single screw was placed, and in three patients two screws were placed. No patient became symptom-free after surgery. Slip progression was noted on average 5 months after treatment. Radiographs in all patients revealed an increase in slip severity and loss of screw purchase in the femoral neck while fixation in the proximal femoral epiphysis remained secure. One patient had hypothyroidism and another Cushing disease, both diagnosed after the slipped epiphysis. Slips occurring in children with underlying endocrinopathies, and unstable slips in children with a history of antecedent knee or hip pain (commonly called an acute-on-chronic slip) may be susceptible to screw fixation failure. In such patients, close radiographic follow-up, particularly in the presence of continued symptoms, is required to document slip progression and fixation failure as soon as possible. PMID:11856939

Sanders, James O; Smith, William J; Stanley, Earl A; Bueche, Matthew J; Karol, Lori A; Chambers, Henry G

2002-01-01

143

Great Earthquakes With and Without Large Slip to the Trench  

NASA Astrophysics Data System (ADS)

The 2011 Tohoku-oki earthquake produced a huge amount of slip (40 to 60 meters) on the shallow portion of the subduction zone close to the trench. This large displacement was largely unexpected for this region and caused the very large and damaging tsunami along the northeast coast of Honshu. For other subduction zones around the world, we examine the possibility of large slip to the trench in past large and great earthquakes. Since the trench region is generally far offshore, it is often difficult to resolve the amount of slip from onland geodetic and strong-motion data. We use a variety of observations, including slip distribution models, aftershock locations, local coastal deformation, and tsunami heights to determine which events likely had large amounts of slip close to the trench. Tsunami earthquakes, such as 1992 Nicaragua and 2006 Java likely had large shallow slip. Some typical subduction earthquakes, such as 1968 Tokachi-oki and 2003 Tokachi-oki (located in regions north of the source area of the 2011 Tohoku-oki earthquake) likely did not. We will discuss possible factors that influence the slip distribution on the shallow area of subduction megathrusts. Using results from the Japan Trench Fast Drilling Project (JFAST) which sampled the fault in the region of large slip, we can begin to understand the conditions of very large fault slip. Are there characteristic features in the material properties for faults that have large slip ? Can we determine if these regions have high plate coupling and accumulate stress ?

Mori, J. J.

2013-12-01

144

Geodetic slip rates in the southern San Andreas Fault system: Investigation of the effects of heterogeneous elastic structure  

NASA Astrophysics Data System (ADS)

We investigate the importance of fault geometry and crustal heterogeneity on estimates of slip rates and locking depths of the Southern San Andreas fault (SAF) and San Jacinto fault (SJF). Previous estimates of geodetic slip rates in the Salton Sea region based on dislocation models have generally inferred a higher slip rate on the SAF (21-26 mm/yr) compared to the SJF (12-19 mm/yr). The inferred geodetic slip rate on the SAF is higher than recent geologic estimates representing average slip rates on time scales of 10^4-10^6 years. We investigate to what extent the geodetically inferred slip rate might be biased by incorrect assumptions about the fault geometry and neglect of spatial variations in crustal rigidity. To address this issue, we use a forward model that incorporates heterogeneous elastic moduli computed from the SCEC CVM-H seismic tomography model of Southern California. In our inversions we allow for a non-vertical SAF and a "blind" segment of the SJF, the previously suggested southern continuation of the Clark fault. The models are compared to surface velocities derived from a combination of all available continuous and campaign GPS sites in the region, processed in a consistent North American fixed frame (NAFD), and InSAR data spanning 18 years (1992-2010). These data sources are strongly complementary: while InSAR provides higher spatial resolution in the near-fault region, we find that GPS sites located more than 10 locking depths from the fault are required to resolve the trade-off between locking depth and fault slip rate. The parameter space is examined using an efficient Monte Carlo algorithm which approximates the joint probability distribution for the model parameters and allows for a formal evaluation of uncertainties and trade-offs. We estimate slip rates of 15(+/-2) mm/yr for the Southern San Andreas fault and a total of 23(+/-3) mm/yr for the two closely spaced branches of the southern San Jacinto fault, in reasonable agreement with geologic estimates. The locking depths are estimated at 9(+/-3) km and 16(+/-3) km for the SAF and SJF, respectively. The incorporation of realistic elastic properties serves to increase the estimated locking depths on both faults by 2-3 km, and decreases the estimated slip rate on the San Andreas fault by several mm/yr in comparison to a homogeneous elastic model.

Lindsey, E. O.; Fialko, Y.

2011-12-01

145

Coseismic slip distribution of the 1923 Kanto earthquake, Japan  

USGS Publications Warehouse

The slip distribution associated with the 1923 M = 7.9 Kanto, Japan, earthquake is reexamined in light of new data and modeling. We utilize a combination of first-order triangulation, second-order triangulation, and leveling data in order to constrain the coseismic deformation. The second-order triangulation data, which have not been utilized in previous studies of 1923 coseismic deformation, are associated with only slightly smaller errors than the first-order triangulation data and expand the available triangulation data set by about a factor of 10. Interpretation of these data in terms of uniform-slip models in a companion study by Nyst et al. shows that a model involving uniform coseismic slip on two distinct rupture planes explains the data very well and matches or exceeds the fit obtained by previous studies, even one which involved distributed slip. Using the geometry of the Nyst et al. two-plane slip model, we perform inversions of the same geodetic data set for distributed slip. Our preferred model of distributed slip on the Philippine Sea plate interface has a moment magnitude of 7.86. We find slip maxima of ???8-9 m beneath Odawara and ???7-8 m beneath the Miura peninsula, with a roughly 2:1 ratio of strike-slip to dip-slip motion, in agreement with a previous study. However, the Miura slip maximum is imaged as a more broadly extended feature in our study, with the high-slip region continuing from the Miura peninsula to the southern Boso peninsula region. The second-order triangulation data provide good evidence for ???3 m right-lateral strike slip on a 35-km-long splay structure occupying the volume between the upper surface of the descending Philippine Sea plate and the southern Boso peninsula. Copyright 2005 by the American Geophysical Union.

Pollitz, F.F.; Nyst, M.; Nishimura, T.; Thatcher, W.

2005-01-01

146

Processing of Yttria-Alumina Coated Silicon Nitride Slips by Slip Casting  

Microsoft Academic Search

Si3N4powders coated with 6 wt% Y2O3and 4 wt% Al2O3were prepared by coprecipitation. The resulting powders were dispersed in water at different pH values and with addition of various amounts of ammonium polyacrylate (NH4PA) to produce 32 vol% slips. The influence of the amount of NH4PA solution added and pH on the rheological properties of 32 vol% coated Si3N4slips were studied.

María P. Albano; Liliana B. Garrido

2002-01-01

147

Knee joint replacement  

MedlinePLUS

Knee joint replacement is surgery to replace a knee joint with a man-made joint. The artificial joint is called a prosthesis . ... cartilage and bone are removed from the knee joint. Man-made pieces are then placed in the ...

148

Identification of maximum road friction coefficient and optimal slip ratio based on road type recognition  

NASA Astrophysics Data System (ADS)

The identification of maximum road friction coefficient and optimal slip ratio is crucial to vehicle dynamics and control. However, it is always not easy to identify the maximum road friction coefficient with high robustness and good adaptability to various vehicle operating conditions. The existing investigations on robust identification of maximum road friction coefficient are unsatisfactory. In this paper, an identification approach based on road type recognition is proposed for the robust identification of maximum road friction coefficient and optimal slip ratio. The instantaneous road friction coefficient is estimated through the recursive least square with a forgetting factor method based on the single wheel model, and the estimated road friction coefficient and slip ratio are grouped in a set of samples in a small time interval before the current time, which are updated with time progressing. The current road type is recognized by comparing the samples of the estimated road friction coefficient with the standard road friction coefficient of each typical road, and the minimum statistical error is used as the recognition principle to improve identification robustness. Once the road type is recognized, the maximum road friction coefficient and optimal slip ratio are determined. The numerical simulation tests are conducted on two typical road friction conditions(single-friction and joint-friction) by using CarSim software. The test results show that there is little identification error between the identified maximum road friction coefficient and the pre-set value in CarSim. The proposed identification method has good robustness performance to external disturbances and good adaptability to various vehicle operating conditions and road variations, and the identification results can be used for the adjustment of vehicle active safety control strategies.

Guan, Hsin; Wang, Bo; Lu, Pingping; Xu, Liang

2014-09-01

149

Pivoting and slip in an angular contact bearing  

NASA Technical Reports Server (NTRS)

Pivoting slips are calculated for the ball-race and ball-ball contacts in a retainerless bearing. The calculation is kinematic, ignoring all inertial loadings. Pure spin and uniform precession of the balls are considered. Pivoting slip magnitudes are compared with several other kinds of slip which were previously reported in an R4 size bearing. Previously announced in STAR as N83-26079

Kingsbury, E.

1984-01-01

150

Pivoting and Slip in an Angular Contact Bearing  

Microsoft Academic Search

Pivoting slips are calculated for the ball-race and ball-ball contacts in a retainerless bearing. The calculation is kinematic, ignoring all inertial loadings. Pure spin and uniform precession of the balls are considered. Pivoting slip magnitudes are compared with several other kinds of slip which have previously been reported in an R4 size bearing. Presented as an American Society of Lubrication

E. Kingsbury

1984-01-01

151

Multiplate magnetorheological fluid limited slip differential clutch  

NASA Astrophysics Data System (ADS)

This study focuses on the design and characterization of a multi-plate magneto-rheological fluid (MRF) limited slip differential (LSD) clutch. Three-dimensional electromagnetic finite element analyzes are performed to optimize the MRF LSD clutch design. The torque transfer capacity of the clutch is predicted utilizing Bingham-Plastic constitutive model of the MRF. The MRF LSD clutch is tested at different velocities and applied magnetic fields. The clutch heating is also examined under different operating conditions to determine the thermal effects on the torque transfer performance of the multi-plate clutch.

Kavlicoglu, Barkan M.; Gordaninejad, Faramarz; Evrensel, Cahit A.; Fuchs, Alan; Korol, George

2003-08-01

152

Microfluidics: The no-slip boundary condition  

E-print Network

The no-slip boundary condition at a solid-liquid interface is at the center of our understanding of fluid mechanics. However, this condition is an assumption that cannot be derived from first principles and could, in theory, be violated. We present a review of recent experimental, numerical and theoretical investigations on the subject. The physical picture that emerges is that of a complex behavior at a liquid/solid interface, involving an interplay of many physico-chemical parameters, including wetting, shear rate, pressure, surface charge, surface roughness, impurities and dissolved gas.

Eric Lauga; Michael P. Brenner; Howard A. Stone

2005-01-24

153

Episodic Tremor and Slip: Cycles Within Cycles  

NASA Astrophysics Data System (ADS)

Episodic tremor and slip (ETS) events, each with geodetically determined moment magnitudes in the mid-6 range, repeat about every 15 months under the Olympic Peninsula/southern Vancouver Island region. We have automatically searched for non-volcanic tremor in all 5-minute time windows both during the past five ETS events and during the two inter-ETS periods from February, 2007 through April, 2008 and June 2008 through April 2009. Inter-ETS tremor was detected in 5000 windows, which overlap by 50%, so tremor was seen 2% of the time. The catalog of 5-minute tremor locations cluster in time and space into groups we call tremor swarms, revealing 50 inter-ETS tremor swarms. The number of hours of tremor per swarm ranged from about 1 to 68, totaling 374 hours. The inter-ETS tremor swarms generally locate along the downdip side of the major ETS events, and account for approximately 45% of the time that tremor has been detected during the last two entire ETS cycles. Many of the inter-ETS events are near-carbon copies in duration, spatial extent and propagation direction, as is seen for the larger 15-month-interval events. These 50 inter-ETS swarms plus two major ETS episodes follow a power law relationship such that the number of swarms, N, exceeding duration ? is given by N ˜ ?-0.7. If we assume that seismic moment is proportional to ? as proposed by Ide et al. [Nature, 2007], we find that the tremor swarms follow a standard Gutenberg-Richter logarithmic frequency-magnitude relation, N ˜ 10-bMw, with b = 1.0, which lies in the range for normal earthquake catalogs. Furthermore, the major ETS events fall on the curve defined by the inter-ETS swarms, suggesting that the inter-ETS swarms are just smaller versions of the major 15-month ETS events. Only the largest events coincide with geodetically observed slip, suggesting that current geodetic observations may be missing nearly half of the total slip. Finally, crude estimates of the spatial dimensions of tremor swarms L suggest that L ˜ ?1/n where n is between 2 and 3. A value of 2 is consistent with slip propagation rates being controlled by a diffusional process. In contrast, n is observed to be about 1 for normal earthquakes because rupture generally propagates at a velocity close to the shear-wave speed.

Creager, K. C.; Wech, A.; Vidale, J. E.

2009-12-01

154

Strong dynamical effects during stick-slip adhesive peeling  

E-print Network

We consider the classical problem of the stick-slip dynamics observed when peeling a roller adhesive tape at a constant velocity. From fast imaging recordings, we extract the dependencies of the stick and slip phases durations with the imposed peeling velocity and peeled ribbon length. Predictions of Maugis and Barquins [in Adhesion 12, edited by K.W. Allen, Elsevier ASP, London, 1988, pp. 205--222] based on a quasistatic assumption succeed to describe quantitatively our measurements of the stick phase duration. Such model however fails to predict the full stick-slip cycle duration, revealing strong dynamical effects during the slip phase.

Marie-Julie Dalbe; Stéphane Santucci; Pierre-Philippe Cortet; Loïc Vanel

2013-11-14

155

A note on the stability of slip channel flows  

E-print Network

We consider the influence of slip boundary conditions on the modal and non-modal stability of pressure-driven channel flows. In accordance with previous results by Gersting (1974) (Phys. Fluids, 17) but in contradiction with the recent investigation of Chu (2004) (C.R. Mecanique, 332), we show that slip increases significantly the value of the critical Reynolds number for linear instability. The non-modal stability analysis however reveals that the slip has a very weak influence on the maximum transient energy growth of perturbations at subcritical Reynolds numbers. Slip boundary conditions are therefore not likely to have a significant effect on the transition to turbulence in channel flows.

Eric Lauga; Carlo Cossu

2005-03-30

156

Slip flow of diverse liquids on robust superomniphobic surfaces.  

PubMed

Water slips exist over superhydrophobic solid surfaces, but the slip flow of diverse liquids on a single surface has not been deliberately studied to date. Here, we report the slip flow behavior of a variety of liquids with different surface tensions and viscosities on a robust omniphobic surface. This surface displayed a dramatic slippage effect and thus a high drag reduction efficiency of approximately 10-20% for all liquids, depending on both liquid viscosity and surface energy. The observed liquid slip was attributed to the surface dual micro/nanostructure and the low-surface-energy coating. PMID:24231078

Wu, Yang; Cai, Meirong; Li, Zhenquan; Song, Xinwang; Wang, Hongyan; Pei, Xiaowei; Zhou, Feng

2014-01-15

157

Micromechanics of slip bands on a free surface  

NASA Technical Reports Server (NTRS)

A micromechanics analysis for the formation and propagation of slip bands on the free surface of a polycrystal under monotonic loading is presented. For the growth of slip bands, the analysis satisfies the conditions of both equilibrium and displacement continuity, as well as the relation between slip and the resolved shear stress throughout the polycrystal. Numerical calculations show how the microstress field causes the concentration of plastic deformation in discrete sliding bands and give results which are in good qualitative agreement with known slip band observations on aluminum single crystals.

Lin, S. R.; Lin, T. H.

1976-01-01

158

Coseismic slip distribution of the 1946 Nankai earthquake and aseismic slips caused by the earthquake  

Microsoft Academic Search

Coseismic slip distribution on the fault plane of the 1946 Nankai earthquake (Mw 8.3) was estimated from inversion of tsunami waveforms. The following three improvements from the previous study (Satake, 1993) were made. (1) Larger number of smaller subfaults is used; (2) the subfaults fit better to the slab geometry; and (3) more detailed bathymetry data are used. The inversion

Yuichiro Tanioka; Kenji Satake

2001-01-01

159

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

PubMed

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 (VR training and control). Both groups went through three sessions including baseline slip, training, and transfer of training on slippery surface. The training group experienced 12 simulated slips using a visual perturbation induced by tilting a VR scene while walking on the treadmill and the control group completed normal walking during the training session. Kinematic, kinetic, and electromyography 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

Parijat, Prakriti; Lockhart, Thurmon E; Liu, Jian

2015-02-01

160

Mineral decomposition during seismic slip: slip-weakening of fault zones and temperature-limiting effects  

Microsoft Academic Search

During an earthquake, the heat generated by fault friction may be large enough to activate the devolatilization of minerals forming the fault rocks. Since devolatilization consumes heat and minerals to release fluids in the shear plane, it is an important process to consider for a better understanding of fault mechanics. The mechanical effects of mineral thermal decomposition on the slip

J. Sulem; V. Famin

2009-01-01

161

Joint x-ray  

MedlinePLUS

X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

162

JOINT SEMINAR FINAL REPORT  

E-print Network

JOINT SEMINAR FINAL REPORT Project number Name of applicant at FWF: __________________________________ Title of the Joint Seminar: ____________________________________________________ Name of the partner): ____________________________________________________ Name of applicant at partner organisation: _______________________ Date and place of Joint Seminar

Fuchs, Clemens

163

Temporomandibular Joint Disorder  

MedlinePLUS

... news feeds delivered directly to your desktop! more... Temporomandibular Joint Disorder Article Chapters Temporomandibular Joint Disorder What ... men. Updated: November 2008 Previous Next Related Articles: Temporomandibular Joint Disorder (TMD) Are You Biting Off More ...

164

Estimating Fault Slip Rates and Deformation at Complex Strike-Slip Plate Boundaries  

NASA Astrophysics Data System (ADS)

Modeling GPS velocity fields in seismically active regions worldwide indicates deformation can be efficiently and usefully described as relative motions among elastic, fault-bounded crustal blocks. These models are providing hundreds of new decadal fault slip rate estimates that can be compared with the (much smaller) independent Holocene (<10 ka) to late Quaternary (<125 ka) rates obtained by geological methods. Updated comparisons show general agreement but a subset of apparently significant outliers. Some of these outliers have been discussed previously and attributed either to a temporal change in slip rate or systematic error in one of the estimates. Here we focus particularly on recent GPS and geologic results from southern California and discuss criteria for assessing the differing rates. In southern California (and elsewhere), subjective choices of block geometry are unavoidable and introduce significant uncertainties in model formulation and in the resultant GPS fault slip rate estimates. To facilitate comparison between GPS and geologic results in southern California we use the SCEC Community Fault Model (CFM) and geologic slip rates tabulated in the 2008 Uniform California Earthquake Rupture Forecast (UCERF2) report as starting points for identifying the most important faults and specifying the block geometry. We then apply this geometry in an inversion of the SCEC Crustal Motion Model (CMM4) GPS velocity field to estimate block motions and intra-block fault slip rates and compare our results with previous work. Here we use 4 criteria to evaluate GPS/geologic slip rate differences. First: Is there even-handed evaluation of random and systematic errors? ‘Random error' is sometimes subjectively estimated and its statistical properties are unknown or idealized. Differences between ~equally likely block models introduces a systematic error into GPS rate estimates that is difficult to assess and seldom discussed. Difficulties in constraining the true initiation date of offset of geomorphic markers by faulting can introduce uncertainties much larger than quoted random errors. Second: Are rate estimates obtained by more than one geodetic or geologic method? For example, agreement between GPS and InSAR slip rate estimates on the Altyn Tagh and Haiyuan faults of Tibet make the geodetic estimates more reliable. Similarly, dating of multiple offset markers of differing age across these faults supports the consistency of the geologic rate estimates. Third: Is proposed rate change mechanism consistent with examples of changes in style and rate of deformation preserved in the geologic record? For example, temporal evolution of the multi-stranded San Andreas system during the past 5-10 Ma (Powell & Weldon 1992; Graymer et al. 2002) indicates activation and deactivation of different faults within the system accompanied by consequent changes in fault slip rate and/or creation of new crustal blocks. Fourth: Is there a quantitative analysis of mechanism proposed to explain rate change? Candidate mechanisms meriting quantitative analysis include (1) changes in frictional resistance of faults and creation of new fractures due to progressive rotation of irregularly shaped blocks, (2) episodic subduction of buoyant lithosphere, and (3) changes in the plate geometry (and so the forces acting) at major continent/ocean plate boundaries (e.g. Late Cenozoic migration of Mendocino triple junction off California). In most parts of southern California—for example, north of the San Andreas Big Bend and SE of Los Angeles--our block geometry closely resembles that assumed in previous studies (McCaffrey 2005 JGR; Meade & Hager 2005 JGR; Becker et al. 2005 GJI). In these regions GPS slip rates can be reliably estimated and values for individual faults generally agree from one study to another and are also consistent with geologic estimates. However, there is no consensus on block geometry in the Transverse Ranges, Los Angeles Basin and Central Mojave Desert, where CFM faults are densely distributed, UCERF2 slip rates on sever

Thatcher, Wayne; Murray-Moraleda, Jessica

2010-05-01

165

Slip Resistance of Casual Footwear: Implications for Falls in Older Adults  

Microsoft Academic Search

Background: A large proportion of falls in older people are caused by slipping. Previous occupational safety research suggests that inadequate footwear may contribute to slipping accidents; however, no studies have assessed the slip resistance of casual footwear. Objective: To evaluate the slip resistance of different types of casual footwear over a range of common household surfaces. Methods: The slip resistance

Hylton B. Menz; Stephen R. Lord; Andrew S. McIntosh

2001-01-01

166

Repeated-Slip Training: An Emerging Paradigm for Prevention of Slip-Related Falls Among Older Adults  

Microsoft Academic Search

Falls frequently cause injury-related hospitalization or death among older adults. This article reviews a new conceptual framework on dynamic stability and weight support in reducing the risk for falls resulting from a forward slip, based on the principles of motor control and learning, in the context of adaptation and longer-term retention induced by repeated-slip training. Although an unexpected slip is

Yi-Chung Pai; Tanvi S Bhatt

167

Fluid pressures at the shoe-floor-contaminant interface during slips: effects of tread and implications on slip severity.  

PubMed

Previous research on slip and fall accidents has suggested that pressurized fluid between the shoe and floor is responsible for initiating slips yet this effect has not been verified experimentally. This study aimed to (1) measure hydrodynamic pressures during slipping for treaded and untreaded conditions; (2) determine the effects of fluid pressure on slip severity; and (3) quantify how fluid pressures vary with instantaneous resultant slipping speed, position on the shoe surface, and throughout the progression of the slip. Eighteen subjects walked on known dry and unexpected slippery floors, while wearing treaded and untreaded shoes. Fluid pressure sensors, embedded in the floor, recorded hydrodynamic pressures during slipping. The maximum fluid pressures (mean+/-standard deviation) were significantly higher for the untreaded conditions (124+/-75 kPa) than the treaded conditions (1.1+/-0.29 kPa). Maximum fluid pressures were positively correlated with peak slipping speed (r=0.87), suggesting that higher fluid pressures, which are associated with untreaded conditions, resulted in more severe slips. Instantaneous resultant slipping speed and position of sensor relative to the shoe sole and walking direction explained 41% of the fluid pressure variability. Fluid pressures were primarily observed for untreaded conditions. This study confirms that fluid pressures are relevant to slipping events, consistent with fluid dynamics theory (i.e. the Reynolds equation), and can be modified with shoe tread design. The results suggest that the occurrence and severity of unexpected slips can be reduced by designing shoes/floors that reduce underfoot fluid pressures. PMID:24267270

Beschorner, Kurt E; Albert, Devon L; Chambers, April J; Redfern, Mark S

2014-01-22

168

Slip Distribution and Seismic Moment of the 2010 and 1960 Chilean Earthquakes Inferred from Tsunami Waveforms and Coastal Geodetic Data  

NASA Astrophysics Data System (ADS)

The slip distribution and seismic moment of the 2010 and 1960 Chilean earthquakes were estimated from tsunami and coastal geodetic data. These two earthquakes generated transoceanic tsunamis, and the waveforms were recorded around the Pacific Ocean. In addition, coseismic coastal uplift and subsidence were measured around the source areas. For the 27 February 2010 Maule earthquake, inversion of the tsunami waveforms recorded at nearby coastal tide gauge and Deep Ocean Assessment and Reporting of Tsunamis (DART) stations combined with coastal geodetic data suggest two asperities: a northern one beneath the coast of Constitucion and a southern one around the Arauco Peninsula. The total fault length is approximately 400 km with seismic moment of 1.7 × 1022 Nm (Mw 8.8). The offshore DART tsunami waveforms require fault slips beneath the coasts, but the exact locations are better estimated by coastal geodetic data. The 22 May 1960 earthquake produced very large, ~30 m, slip off Valdivia. Joint inversion of tsunami waveforms, at tide gauge stations in South America, with coastal geodetic and leveling data shows total fault length of ~800 km and seismic moment of 7.2 × 1022 Nm (Mw 9.2). The seismic moment estimated from tsunami or joint inversion is similar to previous estimates from geodetic data, but much smaller than the results from seismic data analysis.

Fujii, Yushiro; Satake, Kenji

2013-09-01

169

Spacesuit mobility joints  

NASA Technical Reports Server (NTRS)

Joints for use in interconnecting adjacent segments of an hermetically sealed spacesuit which have low torques, low leakage and a high degree of reliability are described. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics. Linkages which restrain the joint from longitudinal distension and a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli are featured. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

Vykukal, H. C. (inventor)

1978-01-01

170

Frictional slip of granite at hydrothermal conditions  

USGS Publications Warehouse

To measure the strength, sliding behavior, and friction constitutive properties of faults at hydrothermal conditions, laboratory granite faults containing a layer of granite powder (simulated gouge) were slid. The mechanical results define two regimes. The first regime includes dry granite up to at least 845?? and wet granite below 250??C. In this regime the coefficient of friction is high (?? = 0.7 to 0.8) and depends only modestly on temperature, slip rate, and PH2O. The second regime includes wet granite above ~350??C. In this regime friction decreases considerably with increasing temperature (temperature weakening) and with decreasing slip rate (velocity strengthening). These regimes correspond well to those identified in sliding tests on ultrafine quartz. The results highlight the importance of fluid-assisted deformation processes active in faults at depth and the need for laboratory studies on the roles of additional factors such as fluid chemistry, large displacements, higher concentrations of phyllosilicates, and time-dependent fault healing. -from Authors

Blanpied, M.L.; Lockner, D.A.; Byerlee, J.D.

1995-01-01

171

Fixed recurrence and slip models better predict earthquake behavior than the time- and slip-predictable models: 2. Laboratory earthquakes  

NASA Astrophysics Data System (ADS)

The behavior of individual stick-slip events observed in three different laboratory experimental configurations is better explained by a "memoryless" earthquake model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. We make similar findings in the companion manuscript for the behavior of natural repeating earthquakes. Taken together, these results allow us to conclude that the predictions of a characteristic earthquake model that assumes either fixed slip or fixed recurrence interval should be preferred to the predictions of the time- and slip-predictable models for all earthquakes. Given that the fixed slip and recurrence models are the preferred models for all of the experiments we examine, we infer that in an event-to-event sense the elastic rebound model underlying the time- and slip-predictable models does not explain earthquake behavior. This does not indicate that the elastic rebound model should be rejected in a long-term-sense, but it should be rejected for short-term predictions. The time- and slip-predictable models likely offer worse predictions of earthquake behavior because they rely on assumptions that are too simple to explain the behavior of earthquakes. Specifically, the time-predictable model assumes a constant failure threshold and the slip-predictable model assumes that there is a constant minimum stress. There is experimental and field evidence that these assumptions are not valid for all earthquakes.

Rubinstein, Justin L.; Ellsworth, William L.; Beeler, Nicholas M.; Kilgore, Brian D.; Lockner, David A.; Savage, Heather M.

2012-02-01

172

Frictional Behavior and Slip Localization in Simulated Faults of Halite at Sub-seismic to Seismic Slip Rates  

NASA Astrophysics Data System (ADS)

Halite exhibits deformation behavior ranging from brittle to plastic at room temperature and at low pressures, and has been used to simulate deformation processes of the brittle-ductile transition zone. However, previous experiments on halite were performed at very low slip rates (10-9-10-3 m/s), requiring friction data at seismic slip rates for a more complete assessment of the applicability of the experimental results to natural earthquakes. We conducted friction experiments on halite at slip rate of 0.02-1.3 m/s and normal stresses of 0.8- 10.0 MPa using a high-velocity rotary shear apparatus. A thin layer (0.6-1.0 mm thick) of halite gouge was inserted between precut rock cylinders jacketed with Teflon sleeve. We found that mechanical behavior and deformation processes of halite gouge are remarkably different depending on slip rate and that frictional melting and dislocation creep can occur simultaneously at seismic slip rates. At sub-seismic slip rates of 0.02 to 0.05 m/sec, peak friction (?p = 0.76-0.85) was followed by steady-state friction (?ss = 0.35-0.37). Gouge layer consists of a thin slip localization zone at the halite gouge-rock contact and a thick low slip-rate zone. The low slip-rate zone shows evidence for cataclastic flow with angular fragments set in a fine matrix. In contrast, the slip localization zone consists of very fine gouge with some remnants of fragments. At seismic slip rates of 0.1 to 1.3 m/sec, ?p (0.64-0.99) was followed by ?ss (0.36-0.03). ?ss decreases with increasing slip rate. The shear zone consists of a thin slip localization zone at the halite gouge-rock contact and a thick low slip-rate zone. The low slip-rate zone consists of polycrystalline halite ribbons highly elongated obliquely to shear zone boundary and the oblique foliation is dragged into the thin slip localization zone. Each ribbon is also defined as a lattice preferred orientation domain by electron back-scattered diffraction (EBSD) analysis. Individual grains within the halite ribbons are also elongated with their long axis subparallel to the ribbons and their grain boundaries are either straight or slightly wavy. The size of the grains within the ribbons gradually decreases toward the slip localization zone. These microfabrics indicate that each halite ribbon results from plastic deformation of the original halite grain, with individual grains within the ribbon representing product of dynamic recrystallization. Their straight or slightly wavy grain boundaries suggest a static adjustment during cooling after deformation. In contrast, the thin slip localization zone consists of very fine euhedral grains (1-3 ?m) at the margin of layer. We interpret that the very fine euhedral grains have grown from frictional melt and the plastic deformation in the low slip-rate zone was enhanced by heat conduction from the slip localization zone. Our experimental results suggest that pseudotachylyte and mylonite may develop simultaneously by 'slip-rate partitioning' at seismic slip rates, providing a new insight into the interpretation of their coexistence. Also, in view of preexisting halite friction data at lower slip rates, halite gouge exhibits a slight velocity weakening at low velocity regime (10-9-10-5 m/s), velocity strengthening at intermediate velocity regime (10-5-10-3 m/s), steady state at sub-seismic velocity regime (10-2-10-1 m/s) and remarkable velocity weakening at seismic velocity regime (> 10-1 m/s).

Kim, J.; Ree, J.; Han, R.; Shimamoto, T.

2007-12-01

173

How is a stick slip rupture initiated?  

NASA Astrophysics Data System (ADS)

We investigated the initiation process of stick slip events that occurred during large scale rock friction experiments conducted on the large scale shaking table at NIED (Fukuyama et al., 2012, AGU Fall meeting). We used a pair of Indian gabbro rock samples stacked vertically and applied normal and shear forces. The sliding area between the samples is 1.5m in length and 0.1m in width. We conducted a sequence of experiments using the same rock sample, and before each experiment we removed gouge particles created during the previous experiment by a brush and a cleaner. Here, we show the experiments under constant slip velocity of 0.1mm/s with constant normal stress of 2.7MPa (LB04-003) or 6.7MPa (LB04-005); the final displacement reached 0.04m. We used 44 acoustic sensors (PZT, vertical mode, 0.5MHz resonance frequency), 32 2-comp strain gouges (SGs) for shear strain and 16 1-comp SGs for normal strain measurements, with 48 0.5MHz dynamic SG amplifiers. We also used a 2MN load cell for shear force measurement and three 0.4MN load cells for vertical forces. Data are recorded continuously at an interval of 10MHz for PZT and 1MHz for other sensors. Just after the shear force applied, many stick slip events (SEs) occurred at an interval of a few seconds. By looking carefully at the PZT and SG array data during an SE, we found that one SE consists of many micro stick slip events (MSEs), which can be grouped into two (the former and the latter). These two groups correspond to the acceleration and deceleration stage of the SE. In LB04-005 (6.7MPa normal stress), a clear nucleation phase can be detected that initiated at a narrow area, propagate slowly (~20m/s) and accelerated. Then, a seismic rupture started to propagate at a velocity of ~3km/s (subshear) or ~6.5km/s (supershear). Detailed features are shown in Mizoguchi et al. (this meeting). It should be noted that this seismic rupture initiated at a narrow area inside the nucleation zone and sometimes after a certain amount of time; it does not seem a smooth transition process from the acceleration to the seismic rupture as proposed in Ohnaka and Shen (1999, JGR). In contrast, under low normal stress case (LB04-003, 2.7MPa), there were no visible nucleation phases but a sequence of foreshocks was observed, which was not dominant in LB04-005. The foreshock slip area was typically around 10cm long. Again, we could not see any visible correlation between the location and preceding time of foreshocks and that of seismic rupture initiation. By looking at the fault surface topography that was recorded as photograph images before and after the experiment, in the nucleation zone, grooves are not developed, while outside the nucleation area, grooves are well developed. Grooves are caused by the creation of gouge particles during the sliding. It could be interesting to note that outside the groove, the sliding surface looks very smooth and shiny, indicating that this area was polished but did not create gouge particles. Therefore, we might speculate that this shiny fault area is responsible for the initiation phase and when the stress state becomes critical, seismic rupture starts around one of the grooves. And in LB04-003, the shiny area might not support the shear stress so that the foreshock releases the strain around the grooves.

Fukuyama, E.; Mizoguchi, K.; Yamashita, F.; Kawakata, H.; Takizawa, S.

2013-12-01

174

Seismic and aseismic slip on the central Peru megathrust.  

PubMed

Slip on a subduction megathrust can be seismic or aseismic, with the two modes of slip complementing each other in time and space to accommodate the long-term plate motions. Although slip is almost purely aseismic at depths greater than about 40 km, heterogeneous surface strain suggests that both modes of slip occur at shallower depths, with aseismic slip resulting from steady or transient creep in the interseismic and postseismic periods. Thus, active faults seem to comprise areas that slip mostly during earthquakes, and areas that mostly slip aseismically. The size, location and frequency of earthquakes that a megathrust can generate thus depend on where and when aseismic creep is taking place, and what fraction of the long-term slip rate it accounts for. Here we address this issue by focusing on the central Peru megathrust. We show that the Pisco earthquake, with moment magnitude M(w) = 8.0, ruptured two asperities within a patch that had remained locked in the interseismic period, and triggered aseismic frictional afterslip on two adjacent patches. The most prominent patch of afterslip coincides with the subducting Nazca ridge, an area also characterized by low interseismic coupling, which seems to have repeatedly acted as a barrier to seismic rupture propagation in the past. The seismogenic portion of the megathrust thus appears to be composed of interfingering rate-weakening and rate-strengthening patches. The rate-strengthening patches contribute to a high proportion of aseismic slip, and determine the extent and frequency of large interplate earthquakes. Aseismic slip accounts for as much as 50-70% of the slip budget on the seismogenic portion of the megathrust in central Peru, and the return period of earthquakes with M(w) = 8.0 in the Pisco area is estimated to be 250 years. PMID:20445628

Perfettini, Hugo; Avouac, Jean-Philippe; Tavera, Hernando; Kositsky, Andrew; Nocquet, Jean-Mathieu; Bondoux, Francis; Chlieh, Mohamed; Sladen, Anthony; Audin, Laurence; Farber, Daniel L; Soler, Pierre

2010-05-01

175

Experimental Characterization of Hysteresis in a Revolute Joint for Precision Deployable Structures  

NASA Technical Reports Server (NTRS)

Recent studies of the micro-dynamic behavior of a deployable telescope metering truss have identified instabilities in the equilibrium shape of the truss in response to low-energy dynamic loading. Analyses indicate that these micro-dynamic instabilities arise from stick-slip friction within the truss joints (e.g., hinges and latches). The present study characterizes the low-magnitude quasi-static load cycle response of the precision revolute joints incorporated in the deployable telescope metering truss, and specifically, the hysteretic response of these joints caused by stick-slip friction within the joint. Detailed descriptions are presented of the test setup and data reduction algorithms, including discussions of data-error sources and data-filtering techniques. Test results are presented from thirteen specimens, and the effects of joint preload and manufacturing tolerances are investigated. Using a simplified model of stick-slip friction, a relationship is made between joint load-cycle behavior and micro-dynamic dimensional instabilities in the deployable telescope metering truss.

Lake, Mark S.; Fung, Jimmy; Gloss, Kevin; Liechty, Derek S.

1997-01-01

176

Western Joint Occupational Health and Safety Committee Workplace Safety Inspection Guide/Checklist  

E-print Network

Western Joint Occupational Health and Safety Committee Workplace Safety Inspection Guide) by the supervisor? Basic Safety Y N N/A Are aisles, walkways and exits clear and all walking surfaces slip free? Y N N/A Is there a current inventory all hazardous substances in the lab? Y N N/A Do the workers know

Sinnamon, Gordon J.

177

Constraining slip rates and spacings for active normal faults  

Microsoft Academic Search

Numerous observations of extensional provinces indicate that neighbouring faults commonly slip at different rates and, moreover, may be active over different time intervals. These published observations include variations in slip rate measured along-strike of a fault array or fault zone, as well as significant across-strike differences in the timing and rates of movement on faults that have a similar orientation

Patience A Cowie; Gerald P Roberts

2001-01-01

178

Effect of patterned slip on micro- and nanofluidic flows  

Microsoft Academic Search

We consider the flow of a Newtonian fluid in a nano- or microchannel with walls that have patterned variations in slip length. We formulate a set of equations to describe the effects on an incompressible Newtonian flow of small variations in slip and solve these equations for slow flows. We test these equations using molecular dynamics simulations of flow between

S. C. Hendy; M. Jasperse; J. Burnell

2005-01-01

179

Slip corona surrounding bilayer graphene nanopore Yunwei Maob  

E-print Network

Slip corona surrounding bilayer graphene nanopore Liang Qi,a Yunwei Maob and Ju Li*abc Received 5th structure of ``slip corona'' on BLG, which is a transition region between A­A stacking close to a nanopore composed of bilayer edges (BLEs) and A­ B stacking far away. For an extremely small nanopore (diameter

Chen, Sow-Hsin

180

Large area multiturn superfluid phase slip gyroscope Niels Brucknera)  

E-print Network

Large area multiturn superfluid phase slip gyroscope Niels Brucknera) and Richard Packard 15 November 2002 We have built and tested a large area multiturn superfluid 4 He phase slip gyroscope-of-principle model, with an improvement in sensitivity of 20 over any other superfluid 4 He gyroscope. We find

Packard, Richard E.

181

On accident analysis and slip-resistance measurement  

Microsoft Academic Search

Four accident analysis models are discussed in relation to a specimen slipping accident. One classification, or ‘single-type’ model, commonly used in accident statistics, lumps all events and agencies from each accident in one ‘cause’ group. This may lead to serious underestimates of particular hazards. In past occupational injury statistics for Sweden, slipping appeared in less than 5 % of all

LENNART STRANDBERG

1983-01-01

182

Procedures for Evaluating Bathing Facility Slip and Fall Accidents  

Microsoft Academic Search

Bathing facility slip and fall injuries are a significant part of the great number of slip and fall accidents that occur each year in the United States. As a consequence, they are an important factor in personal injury allegations in both litigation and insurance claims. One of the key problems faced both by attorneys and insurance adjustors, however, is sufficient

Melvin M. Friedlander

183

Role of Slip Mode on Stress Corrosion Cracking Behavior  

NASA Astrophysics Data System (ADS)

In this article, we examine the effect of aging treatment and the role of planarity of slip on stress corrosion cracking (SCC) behavior in precipitation-hardened alloys. With aging, the slip mode can change from a planar slip in the underage (UA) to a wavy slip in the overage (OA) region. This, in turn, results in sharpening the crack tip in the UA compared to blunting in the OA condition. We propose that the planar slip enhances the stress concentration effects by making the alloys more susceptible to SCC. In addition, the planarity of slip enhances plateau velocities, reduces thresholds for SCC, and reduces component life. We show that the effect of slip planarity is somewhat similar to the effects of mechanically induced stress concentrations such as due to the presence of sharp notches. Aging treatment also causes variations in the matrix and grain boundary (GB) microstructures, along with typical mechanical and SCC properties. These properties include yield stress, work hardening rate, fracture toughness K IC , thresholds K Iscc, and steady-state plateau velocity ( da/ dt). The SCC data for a wide range of ductile alloys including 7050, 7075, 5083, 5456 Al, MAR M steels, and solid solution copper-base alloys are collected from the literature. Our assertion is that slip mode and the resulting stress concentration are important factors in SCC behavior. This is further supported by similar observations in many other systems including some steels, Al alloys, and Cu alloys.

Vasudevan, A. K.; Sadananda, K.

2011-02-01

184

Three cases of slipped capital femoral epiphysis in one family.  

PubMed

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 <26 kg/m(2); had no record of any hormonal imbalances or endocrine abnormalities; had good nutrition; and presented with atypical characteristics of 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. PMID:21815585

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

2011-08-01

185

Hydrodynamic Swirl Decay in Microtubes with Interfacial Slip  

Microsoft Academic Search

The decay of swirl in a laminar swirling flow of liquid through a microtube is numerically investigated. The Navier-Stokes equations are solved with velocity slip at the wall. The influences of swirl–slip interactions on swirl decay are investigated. The decay of swirl is quantified by the variation in the ratio of swirl number at a section with that at the

P. Kaushik; Sukumar Pati; S. K. Som; Suman Chakraborty

2012-01-01

186

Fusion by earthquake fault friction: Stick or slip?  

Microsoft Academic Search

Field observations of pseudotachylites and experimental studies of high-speed friction indicate that melting on a slipping interface may significantly affect the magnitude of shear stresses resisting slip. We investigate the effects of rock melting on the dynamic friction using theoretical models of shear heating that couple heat transfer, thermodynamics of phase transitions, and fluid mechanics. Results of laboratory experiments conducted

Yuri Fialko; Yakov Khazan

2005-01-01

187

Thermal slip for liquids at rough solid surfaces  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulation is used to examine the thermal slip of liquids at rough solid surfaces as characterized by fractal Cantor structures. The temperature profiles, potential energy distributions, thermal slip, and interfacial thermal resistance are investigated and evaluated for a variety of surface topographies. In addition, the effects of liquid-solid interaction, surface stiffness, and boundary condition on thermal slip length are presented. Our results indicate that the presence of roughness expands the low potential energy regions in adjacent liquids, enhances the energy transfer at liquid-solid interface, and decreases the thermal slip. Interestingly, the thermal slip length and thermal resistance for liquids in contact with solid surfaces depends not only on the statistical roughness height, but also on the fractal dimension (i.e., topographical spectrum).

Zhang, Chengbin; Chen, Yongping; Peterson, G. P.

2014-06-01

188

Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.  

PubMed

Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions. These microstructures and associated frictional data suggest a fault-slip mechanism resembling classical Ashby-Verrall superplasticity, capable of producing unstable fault slip. Diffusive mass transfer in nanocrystalline calcite gouge is shown to be fast enough for this mechanism to control seismogenesis in limestone terrains. With nanogranular fault surfaces becoming increasingly recognized in crustal faults, the proposed mechanism may be generally relevant to crustal seismogenesis. PMID:25504714

Verberne, Berend A; Plümper, Oliver; de Winter, D A Matthijs; Spiers, Christopher J

2014-12-12

189

Learning and Prediction of Slip from Visual Information  

NASA Technical Reports Server (NTRS)

This paper presents an approach for slip prediction from a distance for wheeled ground robots using visual information as input. Large amounts of slippage which can occur on certain surfaces, such as sandy slopes, will negatively affect rover mobility. Therefore, obtaining information about slip before entering such terrain can be very useful for better planning and avoiding these areas. To address this problem, terrain appearance and geometry information about map cells are correlated to the slip measured by the rover while traversing each cell. This relationship is learned from previous experience, so slip can be predicted remotely from visual information only. The proposed method consists of terrain type recognition and nonlinear regression modeling. The method has been implemented and tested offline on several off-road terrains including: soil, sand, gravel, and woodchips. The final slip prediction error is about 20%. The system is intended for improved navigation on steep slopes and rough terrain for Mars rovers.

Angelova, Anelia; Matthies, Larry; Helmick, Daniel; Perona, Pietro

2007-01-01

190

Thermal slip for liquids at rough solid surfaces.  

PubMed

Molecular dynamics simulation is used to examine the thermal slip of liquids at rough solid surfaces as characterized by fractal Cantor structures. The temperature profiles, potential energy distributions, thermal slip, and interfacial thermal resistance are investigated and evaluated for a variety of surface topographies. In addition, the effects of liquid-solid interaction, surface stiffness, and boundary condition on thermal slip length are presented. Our results indicate that the presence of roughness expands the low potential energy regions in adjacent liquids, enhances the energy transfer at liquid-solid interface, and decreases the thermal slip. Interestingly, the thermal slip length and thermal resistance for liquids in contact with solid surfaces depends not only on the statistical roughness height, but also on the fractal dimension (i.e., topographical spectrum). PMID:25019794

Zhang, Chengbin; Chen, Yongping; Peterson, G P

2014-06-01

191

Stick-slip substructure in rapid tape peeling  

NASA Astrophysics Data System (ADS)

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?m 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 ˜100m/s , which promotes the sound, so characteristic of this phenomenon.

Thoroddsen, S. T.; Nguyen, H. D.; Takehara, K.; Etoh, T. G.

2010-10-01

192

Joint ownership and alienability  

Microsoft Academic Search

Most legal traditions view individual ownership as paradigmatic. Yet most property is jointly owned. This paper analyzes how joint ownership affects alienability by focusing on two fundamental issues raised by joint ownership—the nature of the class of those who may benefit from a joint asset and the nature of the process for making decisions about such an asset. I identify

Clifford G. Holderness

2003-01-01

193

SlipChip for immunoassays in nanoliter volumes  

PubMed Central

This paper describes a SlipChip-based approach to perform bead-based heterogeneous immunoassays with multiple nanoliter-volume samples. As a potential device to analyze the output of the chemistrode, the performance of this platform was tested using low concentrations of biomolecules. Two strategies to perform the immunoassay in the SlipChip were tested: 1) a unidirectional slipping method to combine the well containing a sample with a series of wells preloaded with reagents; 2) a back-and-forth slipping method to introduce a series of reagents to a well containing the sample by reloading and slipping the well containing the reagent. The SlipChips were fabricated with hydrophilic surfaces on the interior of the wells and with hydrophobic surfaces on the face of the SlipChip to enhance filling, transferring, and maintaining aqueous solutions in shallow wells. Nanopatterning was used to increase the hydrophobic nature of the SlipChip surface. Magnetic beads containing the capture antibody were efficiently transferred between wells and washed by serial dilution. An insulin immunoenzymatic assay showed a detection of limit of ~13 pM. Forty eight droplets of nanoliter volume were analyzed in parallel, including an on-chip calibration. The design of the SlipChip is flexible to accommodate other types of immunoassays, both heterogeneous and homogeneous. This work establishes the possibility of using SlipChip-based immunoassays in small volumes for a range of possible applications, including analysis of plugs from a chemistrode, detection of molecules from single cells, and diagnostic monitoring. PMID:20334360

Liu, Weishan; Chen, Delai; Du, Wenbin; Nichols, Kevin P.; Ismagilov, Rustem F.

2010-01-01

194

Local tsunamis and distributed slip at the source  

USGS Publications Warehouse

Variations in the local tsunami wave field are examined in relation to heterogeneous slip distributions that are characteristic of many shallow subduction zone earthquakes. Assumptions inherent in calculating the coseismic vertical displacement field that defines the initial condition for tsunami propagation are examined. By comparing the seafloor displacement from uniform slip to that from an ideal static crack, we demonstrate that dip-directed slip variations significantly affect the initial cross-sectional wave profile. Because of the hydrodynamic stability of tsunami wave forms, these effects directly impact estimates of maximum runup from the local tsunami. In most cases, an assumption of uniform slip in the dip direction significantly underestimates the maximum amplitude and leading wave steepness of the local tsunami. Whereas dip-directed slip variations affect the initial wave profile, strike-directed slip variations result in wavefront-parallel changes in amplitude that are largely preserved during propagation from the source region toward shore, owing to the effects of refraction. Tests of discretizing slip distributions indicate that small fault surface elements of dimensions similar to the source depth can acceptably approximate the vertical displacement field in comparison to continuous slip distributions. Crack models for tsunamis generated by shallow subduction zone earthquakes indicate that a rupture intersecting the free surface results in approximately twice the average slip. Therefore, the observation of higher slip associated with tsunami earthquakes relative to typical subduction zone earthquakes of the same magnitude suggests that tsunami earthquakes involve rupture of the seafloor, whereas rupture of deeper subduction zone earthquakes may be imbedded and not reach the seafloor.

Geist, E.L.; Dmowska, R.

1999-01-01

195

Rover Slip Validation and Prediction Algorithm  

NASA Technical Reports Server (NTRS)

A physical-based simulation has been developed for the Mars Exploration Rover (MER) mission that applies a slope-induced wheel-slippage to the rover location estimator. Using the digital elevation map from the stereo images, the computational method resolves the quasi-dynamic equations of motion that incorporate the actual wheel-terrain speed to estimate the gross velocity of the vehicle. Based on the empirical slippage measured by the Visual Odometry software of the rover, this algorithm computes two factors for the slip model by minimizing the distance of the predicted and actual vehicle location, and then uses the model to predict the next drives. This technique, which has been deployed to operate the MER rovers in the extended mission periods, can accurately predict the rover position and attitude, mitigating the risk and uncertainties in the path planning on high-slope areas.

Yen, Jeng

2009-01-01

196

Mechanics of slip and fracture along small faults and simple strike-slip fault zones in granitic rock  

NASA Astrophysics Data System (ADS)

We exploit quasi-static fracture mechanics models for slip along pre-existing faults to account for the fracture structure observed along small exhumed faults and small segmented fault zones in the Mount Abbot quadrangle of California and to estimate stress drop and shear fracture energy from geological field measurements. Along small strike-slip faults, cracks that splay from the faults are common only near fault ends. In contrast, many cracks splay from the boundary faults at the edges of a simple fault zone. Except near segment ends, the cracks preferentially splay into a zone. We infer that shear displacement discontinuities (slip patches) along a small fault propagated to near the fault ends and caused fracturing there. Based on elastic stress analyses, we suggest that slip on one boundary fault triggered slip on the adjacent boundary fault, and that the subsequent interaction of the slip patches preferentially led to the generation of fractures that splayed into the zones away from segment ends and out of the zones near segment ends. We estimate the average stress drops for slip events along the fault zones as ˜1 MPa and the shear fracture energy release rate during slip as 5 × 102 - 2 × 104 J/m2. This estimate is similar to those obtained from shear fracture of laboratory samples, but orders of magnitude less than those for large fault zones. These results suggest that the shear fracture energy release rate increases as the structural complexity of fault zones increases.

Martel, Stephen J.; Pollard, David D.

1989-07-01

197

Slip-Length Scaling in Large Earthquakes: The Role of Deep-Penetrating Slip below the Seismogenic Layer  

E-print Network

Slip-Length Scaling in Large Earthquakes: The Role of Deep-Penetrating Slip below the Seismogenic with earthquake rupture length for lengths far beyond the length scale set by the seismogenic layer be confined to the seismogenic layer, implies that earthquake stress drop increases as a function of rupture

Shaw, Bruce E.

198

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

199

Strain Wave during the Transient Process of Fault Unstable Slip  

NASA Astrophysics Data System (ADS)

The "stick-slip" model was proposed as an important mechanism for shallow-focus earthquakes. The study on the transient process of fault unstable slip failure is helpful for understanding the earthquake preparatory process, the mechanism of energy released, the precursor and after shake effect. Double shear frictional experiments are conducted for simulating "stick-slip" phenomenon, and a specially designed multi-channel super dynamic strain field observation system is employed to acquire dada continuously with the sample rate of 3,400 samples/second. The rock deformation process can be recorded in detail, especially in the moment of unstable slip (The unstable slip duration is less than two second in experiments). The strain results from super dynamic strain field observation system show that multi-frequency components and tremendous amplitude fluctuation are included in strain signals along the fault. There are three clear phases during the unstable slip progress: pre-slip (phase I), high-frequency strain vibration (phase II) and strain regulating to stop (phase III). Each phase has its own characteristics on duration, strain rate, frequency, amplitude and energy release. There are strong fluctuations in duration of approximately 70ms in phase II. The frequency and maximum amplitude are 300-400Hz and 150~300?? respectively. Main strain energy release takes place at phase II, less than one-tenth of the total slip time, so that the whole course of dislocation or stress drop would not be taken as earthquake simply at least in laboratory. The phase characteristic of the strain wave is probably its inherent attribute of unstable slip process and independent of dynamical loading conditions. The elastic rebound phenomena, considered as one classic earthquake generation model, can be observed clearly by analyzing the rotation of the principal strain axis with strain variation. The rotated angle ranges from 5° to 15° typically. The value and location of precursor slip in phase I are controlled and influenced primarily by the tectonic position. The instantaneous strain wave acquired during the process of fault unstable slip is valuable for describing the stick-slip process. The phase model of strain wave is a key to understanding fault rupture mechanism. The temporal and spatial variation of fault precursor slip may have some predictive significance for earthquake.

Guo, L.; Liu, L.

2011-12-01

200

A simple stick-slip and creep-slip model for repeating earthquakes and its implication for microearthquakes at Parkfield  

USGS Publications Warehouse

If repeating earthquakes are represented by circular ruptures, have constant stress drops, and experience no aseismic slip, then their recurrence times should vary with seismic moment as tr ?? Mo1/3. In contrast, the observed variation for small, characteristic repeating earthquakes along a creeping segment of the San Andreas fault at Parkfield (Nadeau and Johnson, 1998) is much weaker. Also, the Parkfield repeating earthquakes have much longer recurrence intervals than expected if the static stress drop is 10 MPa and if the loading velocity VL is assumed equal to the geodetically inferred slip rate of the fault Vf. To resolve these discrepancies, previous studies have assumed no aseismic slip during the interseismic period, implying either high stress drop or VL ??? Vf. In this study, we show that a model that includes aseismic slip provides a plausible alternative explanation for the Parkfield repeating earthquakes. Our model of a repeating earthquake is a fixed-area fault patch that is allowed to continuously creep and strain harden until reaching a failure threshold stress. The strain hardening is represented by a linear coefficient C, which when much greater than the elastic loading stiffness k leads to relatively small interseismic slip (stick-slip). When C and k are of similar size creep-slip occurs, in which relatively large aseismic slip accrues prior to failure. Because fault-patch stiffness varies with patch radius, if C is independent of radius, then the model predicts that the relative amount of seismic to total slip increases with increasing radius or Mo, consistent with variations in slip required to explain the Parkfield data. The model predicts a weak variation in tr with Mo similar to the Parkfield data.

Beeler, N.M.; Lockner, D.L.; Hickman, S.H.

2001-01-01

201

Evidence for Rapid Slip on Extensional Detachment Faults  

NASA Astrophysics Data System (ADS)

Continental normal faults present significant seismic hazard within densely populated and rapidly-developing regions, yet the slip rates on such structures are generally poorly understood. Most work to date has focused on small, active fault scarps, which offset young sedimentary units, and typically show slip rates of 0-1 mm/yr. The few published studies of very large, old scarps or fault footwalls have suggested slip rates in the range of 3-8 mm/yr (i.e. John and Howard, 1995; Scott et al., 1998; Foster and John, 1999), but these have suffered from large errors. By using a low-closure-temperature thermochronometric system (single crystal (U-Th)/He in apatite), it has been established that a slip rate of 5.3 (+3.7/-1.6) mm/yr, persisting for a period of several millions of years during the mid-Miocene, occurred on the Buckskin-Rawhide detachment; preliminary data suggest that a similarly rapid slip rate also occurred on the nearby Whipple Mts. detachment. This calculated slip rate is very similar to, but more precise than, the rate calculated using apatite fission track ages from the Buckskin Mts. (6.6+/-5.9 mm/yr; Scott et al., 1998). Both the Buckskin-Rawhide detachment and the Whipple Mts. detachment lie within the Colorado River extensional corridor, along the California-Arizona border in the southwestern United States. Slip rates on both faults were determined by plotting (U-Th)/He in apatite cooling ages against distance in the fault slip direction. This approach assumes that each mineral cooling age records the time at which a given piece of rock moved upward through the intersection of a particular near-horizontal isotherm with the dipping fault plane. If that isotherm is stationary, this method allows a slip rate to be determined by recording the time at which each successive piece of rock on the fault plane moved past that same point. Because the (U-Th)/He in apatite method records cooling through a cool, shallow isotherm ( ~75° C), which should move relatively little during extension (c.f. Ketcham, 1996), approximating the isotherm as stationary during extension should result in an underestimate of the slip rate of less than 10%. Proof of such an alarmingly high slip rate raises questions regarding the potential seismic hazard posed by large-offset extensional faults, and the relationship between these rapidly-slipping, large-offset structures and the slower, smaller-offset faults that are more commonly observed as active structures.

Brady, R. J.

2001-12-01

202

Local void and slip model used in BODYFIT-2PE  

SciTech Connect

A local void and slip model has been proposed for a two-phase flow without the need of fitting any empirical parameters. This model is based on the assumption that all bubbles have reached their terminal rise velocities in the two-phase region. This simple model seems to provide reasonable calculational results when compared with the experimental data and other void and slip models. It provides a means to account for the void and slip of a two-phase flow on a local basis. This is particularly suitable for a fine mesh thermal-hydraulic computer program such as BODYFIT-2PE.

Chen, B.C.J.; Chien, T.H.; Kim, J.H.; Lellouche, G.S.

1983-01-01

203

Experimental investigation of slip instability associated with excess pore pressure  

NASA Astrophysics Data System (ADS)

Slow slip events, including non-volcanic tremors, low- and very low-frequency earthquakes, are observed at both the updip and downdip limits of several subduction regions. Recent studies indicate that similar to regular earthquake, these low frequency events rise from shear slip. It is generally accepted that elevated pore fluid pressure plays a significant role in triggering such slip events. In this study, we conducted deformation experiments on porous sedimentary rocks (both intact and saw-cut samples) to investigate the effect of pore fluid pressure on failure mechanisms and slip behaviors. In the first set of experiments, the pore fluid pressure is kept constant during deformation at fully drained conditions. The second set of experiments was conducted at conditions identical to the first until the onset of inelastic failure. At the onset of inelastic failure, we increased pore fluid pressure while continuing the loading at the same strain rate. Comparison of the failure modes and slip behaviors of these two sets of experiments shows interesting results. At low effective pressure, porous rocks failed by brittle faulting. In the brittle faulting regime, samples deformed with excess pore pressure have lower shear strengths compared to samples deformed at the same stress conditions at normal pore pressure. This is consistent with the reported seismicity increase due to wastewater injections. However, there is no detectable different slip behaviors between the two sets. As effective pressure increases, brittle faulting is inhibited and brittle-ductile transition occurs. In the transitional regime, samples deformed with excess pore pressure exhibit slip weakening whereas their normal pore pressure counterparts show strengthening behaviors, which demonstrates that high pore pressure enables slip instability in otherwise stable conditions. Our data show that the stress drop during the high pore pressure induced slip event at the transitional regime is much smaller than that in the brittle regime. Furthermore, between the high pore pressure induced slip event and the slip event during brittle faulting, there is a measurable difference in the relationship of fracture energy versus slip duration, resembling the difference in moment-duration scaling relations observed in slow slip events versus regular earthquakes. We performed quantitative microstructural analyses on the deformed samples to understand the failure mechanisms associated with the slip and excess pore pressure. This study provides the first experimental evidence that excess pore fluid pressure could induce slow slip in an otherwise aseismic fault whereas it enhances seismic slip along a seismic fault. The prevalence of the slow slip events suggests that the phenomenon is not restricted to specific rock types. While the deformation mechanisms responsible for the brittle-ductile transition and the pore pressure increase vary considerably from one tectonic setting to another, our experimental data support the idea that instabilities triggered by high pore pressure can produce slow events in the transitional regime.

Ougier-simonin, A.; Zhu, W.; Banker, J. S.

2012-12-01

204

Experimental investigation of earthquake precursory slip pulses and accelerating creep  

NASA Astrophysics Data System (ADS)

Earthquake nucleation on pre-existing surfaces is governed by frictional instabilities which can be described by state parameters. These parameters may evolve with cumulative slip and progressive acceleration eventually driving the system to catastrophic failure under a given far-field stress. Studying the transition towards catastrophic failure requires stress-controlled experiments, where the dependent variable is the strain accommodated by the slipping zone, and the experimental setting is sensitive enough to allow and detect strain changes. A majority of previous experiments carried out to investigate stick-slip and stable sliding were conducted under strain-rate controlled conditions with biaxial or triaxial apparatus that have limited total slips (usually <1 cm) and limited maximum slip rates (usually <1cm/s). Here, we use a newly-installed rotary shear apparatus at INGV, Rome, to perform experiments on pre-cut ring-shaped samples (50/30 mm ext./int. diameter) in which the shear stress (torque) is gradually increased on the sliding surface until spontaneous slip occurs, at which point the shear stress is maintained and the strain and strain rate are left to evolve whilst being continuously monitored. Experiments were performed at room temperature under room-humidity and vacuum (10E-3 mbar) conditions on micro-gabbro, granite, and calcite marble imposing a constant normal load of 20 MPa. In micro-gabbro, increasing the torque equivalent to a friction coefficient, ?, of 0.2 resulted in spontaneous slip pulses of 4-12 cm with velocity peaks of 6-60 cm/s. Slip pulses coincided with sample dilation. Once a critical torque threshold (?~0.7) was overcome, slip rates increased to the imposed limiting speed (3m/s), and melt lubrication occurred with friction decaying exponentially to a lower steady-state value (?~0.1). In granite, prior to the onset of the main slip weakening event the spontaneous slip pulses intensified in a regular manner (velocity peaks up to 0.3 mm/s and slips up to 0.1 mm). They accommodated a total slip of 1.8 mm without significant sample dilation. In calcite marble, spontaneous accelerating creep without sample dilation started at ?~0.65. A first creep episode proceeded at 0.3 mm/s and a second slower event at 0.02 mm/s. The second event eventually led to the main slip weakening, when slip rate increased progressively, fault lubrication occurred and friction decayed exponentially to ?~0.03. These results show firstly that slip weakening results in catastrophic failure, and secondly that precursory slip episodes may contain a detectable pattern that is specific to rock composition.

Spagnuolo, E.; Nielsen, S. B.; Smith, S.; Violay, M. E.; Niemeijer, A. R.; Di Toro, G.; Di Felice, F.

2011-12-01

205

Peeling-angle dependence of the stick-slip instability during adhesive tape peeling.  

PubMed

The influence of peeling angle on the dynamics observed during the stick-slip peeling of an adhesive tape has been investigated. This study relies on a new experimental setup for peeling at a constant driving velocity while keeping constant the peeling angle and peeled tape length. The thresholds of the instability are shown to be associated with a subcritical bifurcation and bistability of the system. The velocity onset of the instability is moreover revealed to strongly depend on the peeling angle. This could be the consequence of peeling angle dependance of either the fracture energy of the adhesive-substrate joint or the effective stiffness at play between the peeling front and the point at which the peeling is enforced. The shape of the peeling front velocity fluctuations is finally shown to progressively change from typical stick-slip relaxation oscillations to nearly sinusoidal oscillations as the peeling angle is increased. We suggest that this transition might be controlled by inertial effects possibly associated with the propagation of the peeling force fluctuations through elongation waves in the peeled tape. PMID:25363615

Dalbe, Marie-Julie; Santucci, Stéphane; Vanel, Loïc; Cortet, Pierre-Philippe

2014-12-28

206

The Slip History and Source Statistics of Major Slow Slip Events along the Cascadia Subduction Zone from 1998 to 2008  

NASA Astrophysics Data System (ADS)

We estimate the time dependent slip distribution of 16 prominent slow slip events along the northern half of the Cascadia subduction zone from 1998 to 2008. We process continuous GPS data from the PBO, PANGA and WCDA networks from the past decade using GAMIT/GLOBK processing package. Transient surface displacements are interpreted as slip on the plate interface using the Extended Network Inversion Filter. Of these 16 events, 10 events are centered north of Puget Sound, 4 events are resolved around the Columbia River and 1 event is located near Cape Blanco. The February 2003 event is complex, extending from Portland to southern Vancouver Island. Other smaller events beneath Northern Vancouver Island, Oregon and Northern California are not well resolved because of the limited station coverage. We identify two characteristic segments based on the along-strike extent of individual transient slip events in northern Washington. One segment is centered around Port Angeles. Another segment is between the Columbia River and the southern end of Puget Sound. The propagation direction of slow slip events is variable from one event to the next. The maximum cumulative slip for these 16 events is ~ 27 cm, which is centered beneath Port Angeles. This indicates that the strain release by transient slip is not uniform along-strike. In northwestern Washington where cumulative slip is a maximum, the subduction zone bends along-strike and dip of the plate is lower compared to the north and south. We hypothesize that the geometry of the slab plays an important role for focusing transient strain release at this location along the subduction zone. We explore the relationship of source parameters of slow slip using our catalogue of 16 events. The estimated moment magnitude ranges between 6.1 and 6.7. The average stress drop of 0.06-0.1 MPa is nearly two orders of magnitude smaller than that found for normal earthquakes (1-10 MPa). Standard earthquakes follow a scaling relationship where rupture length is proportional to slip amplitude resulting in a nearly constant stress drop. Slow slip events display the similar scaling law up to a possible limit in slip amplitude. We also explore the relationship of event duration to other source parameters.

Gao, H.; Schmidt, D. A.

2008-12-01

207

Stretching and Slipping Liquid Bridges near Cavities  

NASA Astrophysics Data System (ADS)

The dynamics of liquid bridges are relevant to a wide variety of applications including high-speed printing, extensional rheometry, and floating-zone crystallization. Although many studies assume that the contact lines of a bridge are pinned, this is not the case for printing processes such as gravure, lithography, and microcontacting. To address this issue, we use the Galerkin/Finite-Element method to study the stretching of a finite volume of Newtonian liquid confined between two flat plates, one of which is stationary and the other moving. The contact lines are allowed to slip, and we evaluate the effect of the capillary number and contact angle on the amount of liquid transferred to the moving plate. Liquid transfer to the moving plate is found to increase as the contact angle of the stationary plate increases relative to that of the moving plate. When the contact angle is fixed and the capillary number is increased, the liquid transfer improves if the stationary plate is wetting, but worsens if it is non-wetting. The presence of a cavity on the stationary plate significantly affects the contact line motion, often causing pinning at the cavity corner. In these cases, liquid transfer is controlled primarily by the cavity shape, suggesting that the effects of surface topography dominate over those of surface wettability.

Dodds, Shawn; Kumar, Satish; Carvalho, Marcio S.

2008-11-01

208

Supershear Slip Pulse and Off-Fault Damage  

NASA Astrophysics Data System (ADS)

We extend a model of a two-dimensional self-healing slip pulse, propagating dynamically in steady-state with a slip-weakening failure criterion, to the supershear regime, in order to study the off-fault stressing induced by such a slip pulse and investigate features unique to the supershear range. Specifically, we show that there exists a non-attenuating stress field behind the Mach front which radiates high stresses arbitrarily far from the fault (practically this would be limited to distances comparable to the depth of the seismogenic zone), thus being capable of creating fresh damage or inducing Coulomb failure in known structures at large distances away from the main fault. We allow for both strike-slip and dip-slip failure induced by such a slip pulse by evaluating Coulomb stress changes on both known and optimally oriented structures. In particular we look for features of supershear slip pulse that could nucleate a slip-partitioning event at places where reverse or normal faults exist near a major strike-slip feature. We apply this model to study damage features induced during the 2001 Kokoxili (Kunlun) event in Tibet, for which it has been suggested that much of the rupture was supershear. We argue that an interval of simultaneous induced normal faulting is more likely due to a slip partitioning mechanism suggested previously than to the special features of supershear rupture. However, those features do provide an explanation for otherwise anomalous ground cracking at several kilometers from the main fault. In the big bend region of the San Andreas Fault there is active thrust faulting nearby which might be activated by a supershear event. The most vulnerable locations would be those for which part of the presumably seismogenic thrust surface is within ~15-20 km of the SAF, which (considering dip directions) may include the Pleito, Wheeler Ridge, Cucamonga, Clearwater, Frazier Mountain, Alamo, Dry Creek, Arrowhead, Santa Ana, Waterman Canyon, and San Gorgonio faults, and reverse or minor right-reverse sections of the Banning and San Jacinto fault systems. Many nearby strike slip segments could be vulnerable to the distant stressing too, at least if not oriented too close to perpendicular or parallel to the SAF. The degree of vulnerability has a strong dependence, to be documented, on directivity of the rupture on the SAF and orientation of the considered fault segment. We also compare the damage induced by supershear slip pulse with their sub-Rayleigh analogues to look for unique signature left behind by such slip pulses in terms of off-fault damage. We show that off-fault damage is controlled by the speed of the slip-pulse, scaled stress drop, and principal stress orientation of the pre-stress field. We also make some estimates of fracture energy which, for a given net slip and dynamic stress drop, is lower than for a sub-Rayleigh slip pulse, because part of the energy fed by the far-field stress is radiated back along the Mach fronts.

Bhat, H. S.; Dmowska, R.; King, G.; Klinger, Y.; Rice, J. R.

2005-12-01

209

Experimental Characterization of a Flexible Thermal Slip Sensor  

PubMed Central

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. PMID:23202209

Francomano, Maria Teresa; Accoto, Dino; Guglielmelli, Eugenio

2012-01-01

210

Non-slipping domains of a pulled spool  

NASA Astrophysics Data System (ADS)

We have investigated the pulled spool by considering pulling angles up to 360{}^\\circ . Our focus was on downward pulling forces with pulling angles in the range of 180{}^\\circ to 360{}^\\circ . In this range we have found a domain of pulling angles where the spool never starts to slip independent of the strength of the pulling force. The size of the domain depends on the static friction coefficient and on the moment of inertia of the spool. The non-slipping domain is mainly formed around the critical angle where the static friction force becomes zero. For low static friction the non-slipping domain decays into two different domains. We have determined the limiting angles of the non-slipping domains and explored the transitions from a single domain to two separated domains in parameter space.

Wagner, Clemens; Vaterlaus, Andreas

2014-11-01

211

Brittle-viscous deformation, slow slip, and tremor  

NASA Astrophysics Data System (ADS)

Geophysical observations have illuminated a spectrum of fault slip styles from continuous aseismic sliding to fast earthquake slip. We study exhumed intercalated lenses of oceanic crust and sedimentary rocks, deformed to high shear strains. Deformation was partitioned between fractured, rigid blocks, with lengths of tens to hundreds of meters, and surrounding metapelites characterized by interconnected phyllosilicate networks. Under inferred conditions of low effective stress at temperatures > 500°C, locally and transiently elevated shear strain rate in phyllosilicates deforming by dislocation creep can reach those needed for transient slow slip. Concurrently, increased matrix strain rate likely stimulates brittle failure in rigid lenses. The ubiquitous presence of quartz veins and microfractures within rigid material provides evidence for brittle deformation occurring coincident with viscous shearing flow. We suggest that geophysically observed tremor and slow slip may be a manifestation of strain partitioning, where deformation is accommodated viscously in a matrix enveloping rigid lenses.

Fagereng, Åke; Hillary, Graeme W. B.; Diener, Johann F. A.

2014-06-01

212

Torsional Stick-Slip Behavior in WS2 Nanotubes  

NASA Astrophysics Data System (ADS)

We experimentally observed atomic-scale torsional stick-slip behavior in individual nanotubes of tungsten disulfide (WS2). When an external torque is applied to a WS2 nanotube, all its walls initially stick and twist together, until a critical torsion angle, at which the outer wall slips and twists around the inner walls, further undergoing a series of stick-slip torque oscillations. We present a theoretical model based on density-functional-based tight-binding calculations, which explains the torsional stick-slip behavior in terms of a competition between the effects of the in-plane shear stiffness of the WS2 walls and the interwall friction arising from the atomic corrugation of the interaction between adjacent WS2 walls.

Nagapriya, K. S.; Goldbart, Ohad; Kaplan-Ashiri, Ifat; Seifert, Gotthard; Tenne, Reshef; Joselevich, Ernesto

2008-11-01

213

Strike-Slip Faulting and the Tectonic Evolution of Mars  

Microsoft Academic Search

The superposition of contractional and Tharsis-induced stresses on Mars leads to predictions of widespread strike-slip faulting. The locations of previously documented and newly identified faults are used to constrain the contractional history.

J. C. Andrews-Hanna; M. T. Zuber

2007-01-01

214

Temporomandibular Joint Dysfunction  

MedlinePLUS

The temporomandibular joint (TMJ) connects your jaw to the side of your head. When it works well, it enables you to ... For people with TMJ dysfunction, problems with the joint and muscles around it may cause Pain that ...

215

Joint Aspiration (Arthrocentesis)  

MedlinePLUS

... JIA, formerly called rheumatoid arthritis, or JRA), systemic lupus erythematosus (SLE), and Lyme disease. Joint aspiration is ... Lyme Disease Risk Juvenile Idiopathic Arthritis Living With Lupus Bones, Muscles, and Joints Lyme Disease Arthritis Word! ...

216

Large displacement spherical joint  

DOEpatents

A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2002-01-01

217

Cam deformity and hip degeneration are common after fixation of a slipped capital femoral epiphysis  

PubMed Central

Background and purpose — Slipped capital femoral epiphysis is thought to result in cam deformity and femoroacetabular impingement. We examined: (1) cam-type deformity, (2) labral degeneration, chondrolabral damage, and osteoarthritic development, and (3) the clinical and patient-reported outcome after fixation of slipped capital femoral epiphysis (SCFE). Methods — We identified 28 patients who were treated with fixation of SCFE from 1991 to 1998. 17 patients with 24 affected hips were willing to participate and were evaluated 10–17 years postoperatively. Median age at surgery was 12 (10–14) years. Clinical examination, WOMAC, SF-36 measuring physical and mental function, a structured interview, radiography, and MRI examination were conducted at follow-up. Results — Median preoperative Southwick angle was 22o (IQR: 12–27). Follow-up radiographs showed cam deformity in 14 of the 24 affected hips and a Tönnis grade > 1 in 1 affected hip. MRI showed pathological alpha angles in 15 affected hips, labral degeneration in 13, and chondrolabral damage in 4. Median SF-36 physical score was 54 (IQR: 49–56) and median mental score was 56 (IQR: 54–58). These scores were comparable to those of a Danish population-based cohort of similar age and sex distribution. Median WOMAC score was 100 (IQR: 84–100). Interpretation — In 17 patients (24 affected hips), we found signs of cam deformity in 18 hips and early stages of joint degeneration in 10 hips. Our observations support the emerging consensus that SCFE is a precursor of cam deformity, FAI, and joint degeneration. Neither clinical examination nor SF-36 or WOMAC scores indicated physical compromise. PMID:25175666

Klit, Jakob; Gosvig, Kasper; Magnussen, Erland; Gelineck, John; Kallemose, Thomas; Søballe, Kjeld; Troelsen, Anders

2014-01-01

218

Cam deformity and hip degeneration are common after fixation of a slipped capital femoral epiphysis.  

PubMed

Background and purpose - Slipped capital femoral epiphysis is thought to result in cam deformity and femoroacetabular impingement. We examined: (1) cam-type deformity, (2) labral degeneration, chondrolabral damage, and osteoarthritic development, and (3) the clinical and patient-reported outcome after fixation of slipped capital femoral epiphysis (SCFE). Methods - We identified 28 patients who were treated with fixation of SCFE from 1991 to 1998. 17 patients with 24 affected hips were willing to participate and were evaluated 10-17 years postoperatively. Median age at surgery was 12 (10-14) years. Clinical examination, WOMAC, SF-36 measuring physical and mental function, a structured interview, radiography, and MRI examination were conducted at follow-up. Results - Median preoperative Southwick angle was 22o (IQR: 12-27). Follow-up radiographs showed cam deformity in 14 of the 24 affected hips and a Tönnis grade > 1 in 1 affected hip. MRI showed pathological alpha angles in 15 affected hips, labral degeneration in 13, and chondrolabral damage in 4. Median SF-36 physical score was 54 (IQR: 49-56) and median mental score was 56 (IQR: 54-58). These scores were comparable to those of a Danish population-based cohort of similar age and sex distribution. Median WOMAC score was 100 (IQR: 84-100). Interpretation - In 17 patients (24 affected hips), we found signs of cam deformity in 18 hips and early stages of joint degeneration in 10 hips. Our observations support the emerging consensus that SCFE is a precursor of cam deformity, FAI, and joint degeneration. Neither clinical examination nor SF-36 or WOMAC scores indicated physical compromise. PMID:25175666

Klit, Jakob; Gosvig, Kasper; Magnussen, Erland; Gelineck, John; Kallemose, Thomas; Søballe, Kjeld; Troelsen, Anders

2014-12-01

219

Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie & Diagonal Brace Joint Detail; Chord, Panel Post, Tie & Crossbracing Joint Detail - Dunlapsville Covered Bridge, Spanning East Fork Whitewater River, Dunlapsville, Union County, IN

220

Gain-scheduled wheel slip control in automotive brake systems  

Microsoft Academic Search

A wheel slip controller is developed and experimentally tested in a car equipped with electromechanical brake actuators and a brake-by-wire system. A gain scheduling approach is taken, where the vehicle speed is viewed as a slowly time-varying parameter and the model is linearized about the nominal wheel slip. Gain matrices for the different operating conditions are designed using an LQR

Tor A. Johansen; Idar Petersen; Jens Kalkkuhl; Jens Ludemann

2003-01-01

221

Optical Slip Rings for Home Security High-Definition Cameras  

Microsoft Academic Search

A new optical transmission slip ring which has a light pipe at the center of rotation in order to provide a stable 1.25 Gbps high-speed transmission line for high-definition video. This design, using a conventional slip ring, has made it possible to realize the development of a 360-degree endless panning home security camera that supports the transmission of high-definition video

T. Aizawa; M. Sakai; S. Toguchi; K. Hirohashi

2007-01-01

222

Wheel rolling constraints and slip in mobile robots  

SciTech Connect

It is widely accepted that dead reckoning based on the rolling with no slip condition on wheels is not a reliable method to ascertain the position and orientation of a mobile robot for any reasonable distance. We establish that wheel slip is inevitable under the dynamic model of motion using classical results on the accessibility and controllability in nonlinear control theory and an analytical model of rolling of two linearly elastic bodies.

Shekhar, S.

1997-03-01

223

Complexity of Slow Slip Behind the Rupture Front  

NASA Astrophysics Data System (ADS)

Several physical mechanisms have been proposed for generating episodic slow slip, including fault gouge dilatancy at low effective stress, a velocity-weakening/velocity-strengthening transition with increasing slip speed, a fault size that is ``just right'', and appropriate forms of heterogeneity. Each, with various degrees of tuning, appears capable of generating slip speeds, stress drops, recurrence intervals, and migration speeds that are reasonably consistent with observations. In order to distinguish between these mechanisms it will be necessary to throw more observations into the mix. As geodetic data typically lack the necessary temporal and spatial resolution, the most detailed images we have of slow slip to date are inferred from locations of the associated tectonic tremor. In addition to the well-documented along-strike migration speeds of 5-10 km/day, tremor locations have led to the recognition of ``rapid tremor reversals'', that propagate tens of kilometers back in the direction from whence the main front came at roughly 10 times the speed [Houston et al., Nat. Geo., 2011], and ``tremor streaks'' that propagate tens of kilometers in the slip direction, roughly ten times faster still [Shelly et al., G-cubed, 2007; Ghosh et al., G-cubed, 2010]. The details of the time, space, and amplitude distribution of tremor behind the slow slip front may provide useful constraints on models of slow slip. If fortunate, I will report on efforts to more fully characterize tremor activity behind the propagating slow front in Cascadia. If less fortunate, I will explore some of the implications of the proposed mechanisms listed above for the behavior of slip speed behind the rupture front, along the lines of Rubin [G-cubed, 2011].

Rubin, A. M.

2011-12-01

224

Experimental study of stick-slip in Tennessee sandstone  

E-print Network

EXPERIMENTAL STUDY OF STICK-SLIP IN TENNESSEE SANDSTONE A Thesis by JOHN ARTHUR HUMSTON Submitted to the Graduate College of Texas AFM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1972... Major Subject: Geology EXPERIMENTAL STUDY OF STICK-SLIP IN TENNESSEE SANDSTONE A Thesis by JOHN ARTHUR HUMSTON Approved as to style and content by: Chair an Committee Member Head of Department August 1972 ABSTRACT Experimental Study of Stick...

Humston, John Arthur

2012-06-07

225

Wheel rolling constraints and slip in mobile robots  

SciTech Connect

It is widely accepted that dead reckoning based on the rolling with no slip condition on wheels is not a reliable method to ascertain the position and orientation of a mobile robot for any reasonable distance. The author establishes that wheel slip is inevitable under the dynamic model of motion using classical results on the accessibility and controllability in nonlinear control theory and an analytical model of rolling of two linearly elastic bodies.

Shekhar, S.

1997-03-01

226

Holocene slip rate along the Gyaring Co Fault, central Tibet  

NASA Astrophysics Data System (ADS)

geodetic measurements of interseismic deformation in interior Tibet suggest slow strain accumulation, active slip along the right-lateral Gyaring Co Fault is suggested to be between 8 and 21 mm/yr. Reliable geologic constraints on the slip rate along this fault are sparse. Here we document 12 ± 2 m of right-lateral displacement of lacustrine shorelines across the Gyaring Co Fault. Optically stimulated luminescence ages of the shorelines are tightly clustered between 4.1 and 4.4 ka. These data require an average slip rate of 2.2-3.2 mm/yr along the central Gyaring Co Fault during the latter half of the Holocene. Consideration of seismic cycle effects allows the possibility of slightly higher average slip rates, up to 2.2-4.5 mm/yr. Overall, our results suggest that the slip rate along the Gyaring Co Fault is similar to other strike-slip faults in interior Tibet, supporting the notion that active deformation in this region is distributed among numerous, slowly moving faults.

Shi, Xuhua; Kirby, Eric; Lu, Haijian; Robinson, Ruth; Furlong, Kevin P.; Wang, Erchie

2014-08-01

227

Scaling of micro-slip in tangentially loaded rock contact  

NASA Astrophysics Data System (ADS)

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 preceding a global slip event in a stick-slip regime, including the maximum micro-slip. 1. Dieterich, James H. Time Dependent Friction and the Mechanics of Stick-Slip. 1978, Pure and Applied Geophysics, Vol. 116, pp. 790-806. 2. Scholz, C. H. The Critical Slip Distance for Seismic Faulting. 22/29, 1988, Nature, Vol. 336, pp. 761-763. 3. Ohnaka, M. A constitutive scaling law and a unified comprehension for frictional slip failure, shear fracture of intact rock, and earthquake rupture.B2, 2003, Journal of Geophysical Research: Solid Earth, Vol. 108, p. 2080. 4. Marone, C. and Kilgore, B. Scaling of critical slip distance for seismic faulting with shear strain in fault zones. 1993, Nature, Vol. 362, pp. 618-621. 5. Marone, C. and Cox, S.J.D. Scaling of Rock Friction Constitutive Parameters: The Effects of Surface Roughness and Cumulative Offset on Friction of Gabbro. 1994, Pure and Applied Geophysics, Vol. 143, pp. 359-385. 6. Pohrt, R. and Popov, V.L. Normal Contact Stiffness of Elastic Solids with Fractal Rough Surfaces. 2012, Physical Review Letters, Vol. 108, p. 104301. 7. Grzemba, B., et al. Maximum micro-slip in tangential contact of randomly rough self-affine surfaces. 2014, Wear, Vol. 309, pp. 256-258.

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

2014-05-01

228

Transformation of the deformation mechanism from dislocation-mediated slip to homogeneous slip in silver nanowires.  

PubMed

The tensile deformation behavior of silver (Ag) wires with nanometer widths (nanowires (NWs)) was observed by in situ high-resolution transmission electron microscopy combined with subnanonewton force measurements. The Young's modulus, strength, and critical shear stress of the Ag NWs were investigated based on the mechanics of materials at the atomic scale. It was found that when the minimum cross-sectional area of the NWs decreased to less than approximately 3.2 nm2, the critical shear stress increased with a decrease in the area. In addition, when the minimum cross-sectional area decreased to less than approximately 0.5 nm2 before fracture, the critical shear stress reached 0.96 GPa, which exceeded the theoretical shear stress of bulk Ag crystals on {1111} along (110). The present results indicate that the deformation mechanism of Ag NWs transformed from dislocation-mediated slip to homogeneous slip. Therefore, it can be concluded that size reduction to nanometer scale leads to a considerable increase in strength. PMID:23646744

Feng, Jianbo; Kizuka, Tokushi

2013-01-01

229

Sustainable Chemistry, the Spinning Tube-in-Tube (STT(R)) Reactor and GREENSCOPE: Innovation and Industrial Partnerships  

EPA Science Inventory

The chemical industry faces environmental, social and health challenges that are common across all economic sectors. From worker exposure to toxic substances, to product design and use, to the cost and handling of waste disposal, the industry must overcome numerous complex hurdle...

230

Regional Slip Tendency Analysis of the Great Basin Region  

SciTech Connect

Slip and dilation tendency on the Great Basin fault surfaces (from the USGS Quaternary Fault Database) were calculated using 3DStress (software produced by Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by the measured ambient stress field. - Values range from a maximum of 1 (a fault plane ideally oriented to slip or dilate under ambient stress conditions) to zero (a fault plane with no potential to slip or dilate). - Slip and dilation tendency values were calculated for each fault in the Great Basin. As dip is unknown for many faults in the USGS Quaternary Fault Database, we made these calculations using the dip for each fault that would yield the maximum slip or dilation tendency. As such, these results should be viewed as maximum slip and dilation tendency. - The resulting along?fault and fault?to?fault variation in slip or dilation potential is a proxy for along fault and fault?to?fault variation in fluid flow conduit potential. Stress Magnitudes and directions were calculated across the entire Great Basin. Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson?Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005). The minimum horizontal stress direction (Shmin) was contoured, and spatial bins with common Shmin directions were calculated. Based on this technique, we subdivided the Great Basin into nine regions (Shmin <070, 070140). Slip and dilation tendency were calculated using 3DStress for the faults within each region using the mean Shmin for the region. Shmin variation throughout Great Basin are shown on Figure 3. For faults within the Great Basin proper, we applied a normal faulting stress regime, where the vertical stress (sv) is larger than the maximum horizontal stress (shmax), which is larger than the minimum horizontal stress (sv>shmax>shmin). Based on visual inspection of the limited stress magnitude data in the Great Basin, we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46. These values are consistent with stress magnitude data at both Dixie Valley (Hickman et al., 2000) and Yucca Mountain (Stock et al., 1985). For faults within the Walker Lane/Eastern California Shear Zone, we applied a strike?slip faulting stress, where shmax > sv > shmin. Upon visual inspection of limited stress magnitude data from the Walker Lane and Eastern California Shear zone, we chose values such that SHmin/SHmax = .46 and Shmin/Sv= .527 representative of the region. Results: The results of our slip and dilation tendency analysis are shown in Figures 4 (dilation tendency), 5 (slip tendency) and 6 (slip tendency + dilation tendency). Shmin varies from northwest to east?west trending throughout much of the Great Basin. As such, north? to northeast?striking faults have the highest tendency to slip and to dilate, depending on the local trend of shmin. These results provide a first order filter on faults and fault systems in the Great Basin, affording focusing of local?scale exploration efforts for blind or hidden geothermal resources.

Faulds, James E.

2013-09-30

231

Intense interface seismicity triggered by a shallow slow-slip event in the Central-Ecuador subduction zone  

NASA Astrophysics Data System (ADS)

Slow slip events (SSE) are more often associated with non-volcanic tremors than with classical earthquakes. We document here a deformation episode where an abundant seismicity has been triggered by an SSE. In August 2010, a one week long slow-slip event (SSE) with an equivalent moment magnitude of 6.0-6.3 occurred below La Plata Island (Ecuador), south of the rupture area of the Mw=8.8 1906 megathrust earthquake. GPS data reveal that the SSE occurred at a depth of about 10km, within the downdip part of a shallow (<15km), isolated, locked patch along the subduction interface. The availability of both broad-band seismometer and continuous geodetic station located at the La Plata Island, 10km above the SSE, enables a careful analysis of the relationships between slow and rapid processes of stress release along the subduction interface. During the slow slip sequence, the seismic data shows a sharp increase of the local seismicity (see Figure below), with more than 650 earthquakes detected, among which 50 have a moment magnitude between 1.8 and 4.1. However, the cumulative moment released through earthquakes accounts at most for 0.2% of the total moment release estimated from GPS displacements. Most of the largest earthquakes are located along or very close to the subduction interface with focal mechanism consistent with the relative plate motion. These largest events appear to occur randomly during the slow slip sequence, which further evidence that the seismicity is driven by the stress fluctuations related to aseismic slip. A large part of the seismic events observed during the SSE is organized into families of repeating earthquakes, which may indicate a progressive rupture within small locked patches. Recent observations show that this zone of the subduction is prone to SSEs, as evidenced by a new SSE observed in January 2013. These findings offer an a posteriori interpretation of the seismogenesis in the Central-Ecuador subduction zone, where intense seismic swarms have been regularly observed (1977, 1998, 2002, 2005). These swarms have likely been triggered by large magnitude slow-slip events. Joint observations of the geodetic displacement and of the seismicity rate at La Plata Island (ISPT station) during the 2010 SSE. (Red) Number of seismic events detected over 2 hours sessions for an LTA/STA ratio higher than 6.0. (Grey dots) East displacement recorded by the GPS station, calculated every 6 hours.

Vallee, M.; Nocquet, J.; Battaglia, J.; Font, Y.; Segovia, M.; Regnier, M. M.; Mothes, P. A.; Jarrín, P.; Cisneros, D.; Vaca, S.; Yepes, H. A.; Martin, X.; Béthoux, N.; Chlieh, M.

2013-12-01

232

Stress inversion of heterogeneous fault-slip data with unknown slip sense: An objective function algorithm contouring method  

NASA Astrophysics Data System (ADS)

We propose a new method for stress inversion and separation of principal stress states from heterogeneous fault-slip data. The method is semi-automatic, and is based on the moment method of stress inversion (Fry 1999) in combination with the objective function algorithm (OFA) for stress separation (Shan et al 2003). In the presented routine we randomly partition the heterogeneous fault-slip dataset into subsets ranging between one and six. The number of subsets K represents the number of possible mixed stress states in the fault-slip dataset. For each partition number K, we run the OFA 1000 times. Following this we plot and contour the principal stress axes, corresponding to the minimum value of the objective function for each run, in a stereonet. By evaluating how solution clusters of principal stress axes change with increasing number of subsets K, we are able to determine the number of mixed stress states and their optimal solutions for heterogeneous fault-slip datasets. While the numbers of subsets are underestimated, solution-clusters of principal stress axes represent average stress states. However, once the correct number of subsets is reached, solution clusters align with the slip-generating principal stress axes. The solution clusters then become stable, and overestimating the number of subsets does not significantly alter their orientation. The partition number K when stability is obtained thus determines the number of mixed stress states in the heterogeneous dataset, while the corresponding highest density solution clusters give the best estimate of the slip-generating principal stress axes and corresponding stress shape ratios. The inversion routine is tested and confirmed using synthetic data and fault-slip data from the Gullkista fault in Northern Norway. Because the stress calculation is based on the moment method, the inversion routine is insensitive to the correct assessment of slip sense, and only requires the slip vector and orientation of the fault plane as input. It is therefore a robust method to evaluate the number of mixed stress states and their respective stress tensors for complex heterogeneous fault-slip data.

Hansen, John-Are; Bergh, Steffen G.; Osmundsen, Per Terje; Redfield, Tim F.

2015-01-01

233

Slip Running Reconnection in Magnetic Flux Ropes  

NASA Astrophysics Data System (ADS)

Magnetic flux ropes are due to helical currents and form a dense carpet of arches on the surface of the sun. Occasionally one tears loose as a coronal mass ejection and its rope structure can be detected by satellites close to the earth. Current sheets can tear into filaments and these are nothing other than flux ropes. Ropes are not static, they exert mutual ?c{J}×?c{B} forces causing them to twist about each other and eventually merge. Kink instabilities cause them to violently smash into each other and reconnect at the point of contact. We report on experiments on two adjacent ropes done in the large plasma device (LAPD) at UCLA ( ne ˜ 1012, Te ˜ 6 eV, B0z=330G, Brope}\\cong{10G,trep=1 Hz). The currents and magnetic fields form exotic shapes with no ignorable direction and no magnetic nulls. Volumetric space-time data (70,600 spatial locations) show multiple reconnection sites with time-dependent locations. The concept of a quasi-separatrix layer (QSL), a tool to understand and visualize 3D magnetic field lines reconnection without null points is introduced. Three-dimensional measurements of the QSL derived from magnetic field data are presented. Within the QSL field lines that start close to one another rapidly diverge as they pass through one or more reconnection regions. The motion of magnetic field lines are traced as reconnection proceeds and they are observed to slip through the regions of space where the QSL is largest. As the interaction proceeds we double the current in the ropes. This accompanied by intense heating as observed in uv light and plasma flows measured by Mach probes. The interaction of the ropes is clearly seen by vislaulizng magnetic field data , as well as in images from a fast framing camera. Work supported by the Dept. of Energy and The National Science Foundation, done at the Basic Plasma Science Facility at UCLA.Magnetic Field lines (measured) of three flux ropes and the plasma currents associated with them

Gekelman, W. N.; Van Compernolle, B.; Vincena, S. T.; De Hass, T.

2012-12-01

234

A comparison of slip rate, recurrence interval, and slip per event on several well-characterized faults (Invited)  

NASA Astrophysics Data System (ADS)

Rapid growth in the application of LiDAR and other modern geodetic techniques has led to an explosion in the number of micro-geomorphic offsets along faults that can be interpreted as displacement in one or several earthquakes. As a result of this new data there are an increasing number of places along faults for which data are available for the slip rate (based on the dated offset of a feature that is old enough to average out the seismic cycle), recurrence interval (based on a representative number of dated paleo-earthquakes), and slip per event (based on an adequate sample of micro-geomorphic or 3D-excavated offsets). Because these three datasets are largely independent, but related by accumulation and release of strain across the fault, comparing them can provide insight into how faults balance size and frequency of earthquakes. We discuss several examples of faults with closely co-located slip rate, recurrence interval, and slip per event data, including the Ana River fault, a small normal fault in Central Oregon, and portions of the San Andreas fault, the principal plate boundary fault in California. The Ana River fault offsets more than 11 Pleistocene shorelines different amounts that we have measured using a combination of LiDAR, ground-based surveying, and a DEM generated from a USGS topographic map with 5 foot contours. The ages of ~10 paleo-earthquakes are determined from trenches and other exposures into deep-water lacustrine deposits that contain ~50 dated volcanic ashes. The long-term slip rate, 0.05 mm/yr, is known from the total offset of dated late Pliocene basalts. We also use new data from the Santa Cruz segment of the northern San Andreas fault (NSAF) and the southern San Andreas fault (SSAF: Parkfield to Bombay Beach). On the NSAF, earthquakes in 1838, 1890, and 1906 have a total slip of 4 - 6 m while the slip rate (17 mm/yr) suggests it would take 2 - 3 centuries to accumulate this much strain. Data for the SSAF, which have recently been compiled for UCERF-3, include 12 sites with recurrence intervals, hundreds of micro-geomorphic offsets, including at least 7 places with closely-spaced progressively larger offsets that allow one to estimate the average slip per event, and slip rate estimates that vary from about 34 to 12 mm/yr, decreasing from Parkfield to San Gorgonio Pass and then increasing to the southern end of the SSAF. In general the 3 types of data are reasonably consistent (i.e. slip rate (mm/yr) = slip per event (mm) X recurrence interval (1/yr)). Recurrence intervals seem to be more variable than displacements, although displacement variability may be biased by difficulty resolving small offsets with geomorphic markers. Assuming slip rate is constant through time, in places where (or periods of time when) there are inconsistencies between the three parameters it appears to be due to the intervals between earthquakes varying more than displacements, i.e. short intervals are not associated with small enough displacements and long intervals do not yield unusually large displacements. Similarly, as the SSAF changes slip rate along strike the recurrence interval varies more than the size of slip events.

Weldon, R. J.; Lippoldt, R. C.; Scharer, K.; Streig, A. R.; Langridge, R. M.; Madugo, C. M.; Biasi, G. P.; Dawson, T. E.

2013-12-01

235

Late Quaternary Slip Rates of the Sumatran Fault  

NASA Astrophysics Data System (ADS)

The Sumatran Fault accommodates a large portion of the right-lateral, trench-parallel component of relative motion between the northward-subducting India-Australia plates and the overriding Sunda plate. Slip rate estimates for this strike-slip fault have primarily been calculated by dividing the observed horizontal deflection across the fault trace of river valleys incised into voluminous caldera-derived tuffs by the radiometrically-dated eruption age of those tuffs, or by estimating the age of displaced river valleys from the length of the displaced channels [1]. These slip rates exhibited a dramatic northward increase in trench-parallel relative displacement that would have to be accommodated by trench-parallel stretching of the forearc sliver [2]. We present new slip rate estimates for the Sumatran Fault where it traverses the Toba, Maninjau, and Ranau tuffs in northern, central, and southern Sumatra. We re-mapped the deflected drainage networks using high-resolution satellite imagery, digital topography, and field observations. At Toba, the best-fitting slip rate is 13.8 × 0.3 mm/yr, about half the previously published estimate. At Maninjau, the best-fitting slip rate is 14.8 × 0.4 mm/yr, faster than the previous estimates of ~10-11 mm/yr. While a new slip rate for the Ranau area is pending the results of radiometric dating of the incised tuffs, we mapped lateral displacements of river valleys of ~230 m, much smaller than previously estimated displacement of ~2,500 m. The revised Late Pleistocene slip rates at Toba and Maninjau are similar to each other and compare favourably with recent GPS-derived slip-rate estimates for several segments of the Sumatran Fault, suggesting that ~40% of the trench-parallel displacement between the forearc islands and the backarc is accommodated on structures other than the Sumatran Fault [3], and that this situation has persisted for at least the past 50,000 to 74,000 years. [1](Bellier and Sébrier, GRL v.22, 1995) [2] (McCaffrey, Geology v.19, 1992) [3] (Feng et al., in prep.)

Bradley, K.; Sieh, K.; Natawidjaja, D.; Daryono, M. R.

2013-12-01

236

Mechanics of slip and fracture along small faults and simple strike-slip fault zones in granitic rock  

SciTech Connect

We exploit quasi-static fracture mechanics models for slip along pre-existing faults to account for the fracture structure observed along small exhumed faults and small segmented fault zones in the Mount Abbot quadrangle of Calfornia and to estimate stress drop and shear fracture energy from geological field measurements. Along small strike-slip faults, cracks that splay from the faults are common only near fault ends. In contrast, many cracks splay from the boundary faults at the edges of a simple fault zone. Except near segment ends, the cracks preferentially splay into a zone. We infer that shear displacement discontinuities (slip patches) along a small fault propagated to near the fault ends and caused fraturing there. Based on elastic stress analyses, we suggest that slip on one boundary fault ends and caused fracturing there. Based on elastic stress analyses, we suggest that slip patches preferentially led to the generation of fractures that splayed into the zones away from segment ends and out of the zones near segment ends. We estimate the average stress drops for slip events along the fault zones as /similar to/1 MPa and the shear fracture energy release rate during slip as 5/times/10/sup 2//minus/2/times/10/sup 4/ J/m/sup 2/. This estimate is similar to those obtained from shear fracture of laboratory samples, but orders of magnitude less than those for large fault zones. These results suggest that the shear fracture energy release rate increases as the structural complexity of fault zones increases. /copyright/ American Geophysical Union 1989

Martel, S. J.; Pollard, D. D.

1989-07-10

237

Variations in rupture speed, slip amplitude and slip direction during the 2008 Mw 7.9 Wenchuan Earthquake  

NASA Astrophysics Data System (ADS)

Theoretical and observational evidence implies that variable rupture velocity may be associated with high fault slip and high moment release rates during earthquakes. We investigate this relationship for the 2008 Mw 7.9 Wenchuan China, Earthquake, which appears to have experienced a highly variable moment release rate. We used an empirical Green's function (EGF) deconvolution analysis of teleseismic waveforms to retrieve the primary rupture characters for this event. Based on field observations and the deconvolved source-time function from thrust and strike-slip EGFs, we divided the ruptured fault into three segments, allowing us to determine the spatial slip distribution with different average rupture velocities on each segment. We deployed a grid search analysis, in which we integrated the teleseismic waveform inversion and forward modelling of the regional surface wave to determine the optimum rupture speed in each fault segment. Our result shows that the 2008 Wenchuan Earthquake had slip amplitude, direction and rupture velocity that were highly spatially variable. The earthquake initially ruptured with nearly pure thrust motion and a slow rupture velocity of 1.7 km s-1. Then, the rupture speed increased up to 3.1-3.3 km s-1 and produced the largest slip on the second segment, where two parallel faults ruptured simultaneously. Rupture velocity then slowed down to 2.5-2.9 km s-1 on the final segment, which underwent primarily strike-slip motion. In total, the fault extended 300 km with an average rupture speed in the range of 2.6-2.9 km s-1. The high rupture speed (close to the shear wave velocity) in the second segment may be related to the simultaneous rupture of the two parallel faults on well-established pre-existing structures. The spatial distribution of rupture velocity and slip are likely related to the strongly rotational and 3-D deformation in the eastern Tibetan Plateau margin, which leads to the heterogeneous stress field of the Longmen Shan region.

Wen, Yi-Ying; Ma, Kuo-Fong; Oglesby, David D.

2012-07-01

238

Faults smooth gradually as a function of slip  

NASA Astrophysics Data System (ADS)

Geometry and roughness of fault surfaces plays a central role in the dynamics and kinematics of faulting. Faults smooth with increasing slip, but the degree of the smoothing has not previously been well-constrained for natural faults. We measure the roughness as a function of displacement for a suite of 16 faults with cumulative offsets ranging from 0.1 m to approximately 500 m. We find that slip parallel roughness evolves gradually with slip. For instance, for segments of length 0.5 m, H ? 2 × 10-3D-0.1 where H is the RMS roughness and D is the displacement on the fault strand with both quantities measured in meters. The gradual nature of the smoothing is robust to varying lithology and erosion. The weak function implies a decrease in the rate of gouge formation for a model with increasing slip for a model in which gouge is generated by abrading an asperity tip. The relatively gradual evolution of roughness could be explained by lubrication by the accumulated gouge that mitigates the abrasional smoothing that occurs during slip and/or re-roughening processes.

Brodsky, Emily E.; Gilchrist, Jacquelyn J.; Sagy, Amir; Collettini, Cristiano

2011-02-01

239

Path Following with Slip Compensation for a Mars Rover  

NASA Technical Reports Server (NTRS)

A software system for autonomous operation of a Mars rover is composed of several key algorithms that enable the rover to accurately follow a designated path, compensate for slippage of its wheels on terrain, and reach intended goals. The techniques implemented by the algorithms are visual odometry, full vehicle kinematics, a Kalman filter, and path following with slip compensation. The visual-odometry algorithm tracks distinctive scene features in stereo imagery to estimate rover motion between successively acquired stereo image pairs, by use of a maximum-likelihood motion-estimation algorithm. The full-vehicle kinematics algorithm estimates motion, with a no-slip assumption, from measured wheel rates, steering angles, and angles of rockers and bogies in the rover suspension system. The Kalman filter merges data from an inertial measurement unit (IMU) and the visual-odometry algorithm. The merged estimate is then compared to the kinematic estimate to determine whether and how much slippage has occurred. The kinematic estimate is used to complement the Kalman-filter estimate if no statistically significant slippage has occurred. If slippage has occurred, then a slip vector is calculated by subtracting the current Kalman filter estimate from the kinematic estimate. This slip vector is then used, in conjunction with the inverse kinematics, to determine the wheel velocities and steering angles needed to compensate for slip and follow the desired path.

Helmick, Daniel; Cheng, Yang; Clouse, Daniel; Matthies, Larry; Roumeliotis, Stergios

2005-01-01

240

Slip stream apparatus and method for treating water in a circulating water system  

DOEpatents

An apparatus is described for treating water in a circulating water system that has a cooling water basin which includes a slip stream conduit in flow communication with the circulating water system, a source of acid solution in flow communication with the slip stream conduit, and a decarbonator in flow communication with the slip stream conduit and the cooling water basin. In use, a slip stream of circulating water is drawn from the circulating water system into the slip stream conduit of the apparatus. The slip stream pH is lowered by contact with an acid solution provided from the source thereof. The slip stream is then passed through a decarbonator to form a treated slip stream, and the treated slip stream is returned to the cooling water basin. 4 figs.

Cleveland, J.R.

1997-03-18

241

Slip stream apparatus and method for treating water in a circulating water system  

DOEpatents

An apparatus (10) for treating water in a circulating water system (12) t has a cooling water basin (14) includes a slip stream conduit (16) in flow communication with the circulating water system (12), a source (36) of acid solution in flow communication with the slip stream conduit (16), and a decarbonator (58) in flow communication with the slip stream conduit (16) and the cooling water basin (14). In use, a slip stream of circulating water is drawn from the circulating water system (12) into the slip stream conduit (16) of the apparatus (10). The slip stream pH is lowered by contact with an acid solution provided from the source (36) thereof. The slip stream is then passed through a decarbonator (58) to form a treated slip stream, and the treated slip stream is returned to the cooling water basin (14).

Cleveland, Joe R. (West Hills, CA)

1997-01-01

242

Does hydraulic-fracturing theory work in jointed rock masses  

SciTech Connect

The hypocenter locations of micro-earthquakes (acoustic emissions) generated during fracturing typically are distributed three-dimensionally suggesting that fracturing stimulates a volumetric region, rather than the planar fracture theoretically expected. The hypocenter maps generated at six operating, or potential, HDR reservoirs in the US, Europe and Japan are examined in detail and the fracture dimensions are correlated with fracture injection volumes and formation permeability. Depsite the volumetric appearance of the maps we infer that the induced fractures are mainly planar and may propagate aseismically. The induced seismicity stems from nearby joints, which are not opened significantly by fracturing, but are caused to shear-slip because of local pore pressure.

Murphy, H.D.; Keppler, H.; Dash, Z.V.

1983-01-01

243

Mechanics of Suture Joints  

NASA Astrophysics Data System (ADS)

Biological sutures are joints which connect two stiff skeletal or skeletal-like components. These joints possess a wavy geometry with a thin organic layer providing adhesion. Examples of biological sutures include mammalian skulls, the pelvic assembly of the armored fish Gasterosteus aculeatus (the three-spined stickleback), and the suture joints in the shell of the red-eared slider turtle. Biological sutures allow for movement and compliance, control stress concentrations, transmit loads, reduce fatigue stress and absorb energy. In this investigation, the mechanics of the role of suture geometry in providing a naturally optimized joint is explored. In particular, analytical and numerical micromechanical models of the suture joint are constructed. The anisotropic mechanical stiffness and strength are studied as a function of suture wavelength, amplitude and the material properties of the skeletal and organic components, revealing key insights into the optimized nature of these ubiquitous natural joints.

Li, Yaning; Song, Juha; Ortiz, Christine; Boyce, Mary

2011-03-01

244

Sacroiliac joint pain.  

PubMed

The sacroiliac joint is a source of pain in the lower back and buttocks in approximately 15% of the population. Diagnosing sacroiliac joint-mediated pain is difficult because the presenting complaints are similar to those of other causes of back pain. Patients with sacroiliac joint-mediated pain rarely report pain above L5; most localize their pain to the area around the posterior superior iliac spine. Radiographic and laboratory tests primarily help exclude other sources of low back pain. Magnetic resonance imaging, computed tomography, and bone scans of the sacroiliac joint cannot reliably determine whether the joint is the source of the pain. Controlled analgesic injections of the sacroiliac joint are the most important tool in the diagnosis. Treatment modalities include medications, physical therapy, bracing, manual therapy, injections, radiofrequency denervation, and arthrodesis; however, no published prospective data compare the efficacy of these modalities. PMID:15473677

Dreyfuss, Paul; Dreyer, Susan J; Cole, Andrew; Mayo, Keith

2004-01-01

245

The Effect of Patterned Slip on Micro and Nanofluidic Flows  

E-print Network

We consider the flow of a Newtonian fluid in a nano or microchannel with walls that have patterned variations in slip length. We formulate a set of equations to describe the effects on an incompressible Newtonian flow of small variations in slip, and solve these equations for slow flows. We test these equations using molecular dynamics simulations of flow between two walls which have patterned variations in wettability. Good qualitative agreement and a reasonable degree of quantitative agreement is found between the theory and the molecular dynamics simulations. The results of both analyses show that patterned wettability can be used to induce complex variations in flow. Finally we discuss the implications of our results for the design of microfluidic mixers using slip.

Hendy, S C; Burnell, J

2005-01-01

246

Effect of patterned slip on micro- and nanofluidic flows.  

PubMed

We consider the flow of a Newtonian fluid in a nano- or microchannel with walls that have patterned variations in slip length. We formulate a set of equations to describe the effects on an incompressible Newtonian flow of small variations in slip and solve these equations for slow flows. We test these equations using molecular dynamics simulations of flow between two walls which have patterned variations in wettability. Good qualitative agreement and a reasonable degree of quantitative agreement is found between the theory and molecular dynamics simulations. The results of both analyses show that patterned wettability can be used to induce complex variations in flow. Finally we discuss the implications of our results for the design of microfluidic mixers using slip. PMID:16090082

Hendy, S C; Jasperse, M; Burnell, J

2005-07-01

247

ETS and tidal stressing: Fault weakening after main slip pulse  

NASA Astrophysics Data System (ADS)

Time-varying stresses from solid Earth tides and ocean loading influence slow slip (Hawthorne and Rubin, 2010) and, consequently, the frequency of occurrence and intensity of tremor during ETS episodes (Rubinstein et al., 2008). This relationship can illuminate changes in the mechanical response of the rupture surfaces(s) during slip in ETS. I compare the influence of tidal loading when and after the propagating ETS slip front (estimated by tremor density in time) ruptures the fault at a given spot. Using estimates of slip fronts that I derived from tremor locations, I divide ETS tremor into two groups: that occurring within a day of the start of the inferred slip front and that occurring over several days thereafter. The tremor catalog used contains 50K waveform cross-correlation locations of tremor in 7 large ETS in northern Cascadia between 2005 and 2012. I calculate normal, shear and volumetric stresses due to the Earth and ocean tides at numerous locations on the inferred rupture plane of the ETS following the method of Hawthorne and Rubin (2010). The Coulomb stress increment at each tremor time and location is compared with tremor occurrence for the two groups of tremor. Unreasonable results appear if the effective frictional coefficient mu > 0.2, and results are most 'reasonable' when mu is very near or equal to zero. Following passage of the main slip pulse, tremor generation is notably more sensitive to tidal stressing. One kPa of encouraging tidal Coulomb stress boosts the occurrence of tremor after the main slip pulse by about 50% above the average value, while the same amount of discouraging stress decreases the occurrence of such tremor by a similar factor. The greater the encouraging or discouraging stress, the greater the effect. In contrast, tremor in the main slip pulse is much less affected by positive or negative tidal stresses. I interpret the greater sensitivity to tidal stressing of the tremor after the main slip pulse as a measure of the weakening of the fault plane following its initial rupture. Considering up- and down-dip sensitivities to tidal stress, tremor generation on the up-dip region is affected roughly 50% more by both positive and negative tidal stresses than tremor down-dip. Furthermore, for the down-dip tremor, there is less contrast in sensitivity to stress between the tremor at the main slip front and the later tremor, i.e., the fault downdip is both less sensitive to tidal stress and weakens less due to the rupture. These results are consistent with the timing and geometry of Rapid Tremor Reversals, which also indicate weakening of the fault after the main slip front has passed through a region (Houston et al., 2011). RTRs occur on updip parts of the fault, after the main slip front, and at times of encouraging tidal stress (Thomas et al., 2013).

Houston, H.

2013-12-01

248

Surface-slip equations for multicomponent, nonequilibrium air flow  

NASA Technical Reports Server (NTRS)

Equations are presented for the surface slip (or jump) values of species concentration, pressure, velocity, and temperature in the low-Reynolds-number, high-altitude flight regime of a space vehicle. These are obtained from closed-form solutions of the mass, momentum, and energy flux equations using the Chapman-Enskog velocity distribution function. This function represents a solution of the Boltzmann equation in the Navier-Stokes approximation. The analysis, obtained for nonequilibrium multicomponent air flow, includes the finite-rate surface catalytic recombination and changes in the internal energy during reflection from the surface. Expressions for the various slip quantities have been obtained in a form which can readily be employed in flow-field computations. A consistent set of equations is provided for multicomponent, binary, and single species mixtures. Expression is also provided for the finite-rate species-concentration boundary condition for a multicomponent mixture in absence of slip.

Gupta, Roop N.; Scott, Carl D.; Moss, James N.; Goglia, Gene

1985-01-01

249

Surface-slip equations for multicomponent nonequilibrium air flow  

NASA Technical Reports Server (NTRS)

Equations are presented for the surface-slip (or jump) values of species concentration, pressure, velocity, and temperature in the low-Reynolds number, high-altitude flight regime of a space vehicle. The equations are obtained from closed form solutions of the mass, momentum, and energy flux equations using the Chapman-Enskog velocity distribution function. This function represents a solution of the Boltzmann equation in the Navier-Stokes approximation. The analysis, obtained for nonequilibrium multicomponent air flow, includes the finite-rate surface catalytic recombination and changes in the internal energy during reflection from the surface. Expressions for the various slip quantities were obtained in a form which can be employed in flowfield computations. A consistent set of equations is provided for multicomponent, binary, and single species mixtures. Expression is also provided for the finite-rate, species-concentration boundary condition for a multicomponent mixture in absence of slip.

Gupta, R. N.; Scott, C. D.; Moss, J. N.

1985-01-01

250

Supershear Mach-Waves Expose the Fault Breakdown Slip  

NASA Astrophysics Data System (ADS)

During an earthquake, changes in stresses on the fault and within the surrounding material occur as the fault slips and radiates seismic waves. The radiated energy strongly depends on the way these stresses evolve in the rupture front, where most of dissipative mechanisms concentrate. Thus, any constraint obtained from observations on how tractions drop as the fault slips is crucial for understanding the rupture process and the generation of reliable physics-based model predictions. One of the most important parameters controlling the strength drop is the breakdown slip, Dc, which is defined as the slip required by the shear traction to progress from its peak value to its residual value during rupture. Mikumo et al. (2003) showed that it is possible to estimate Dc as the slip at the time of the peak slip rate for rupture propagation with subshear speeds. Fukuyama and Mikumo (2007) later attempted to extend this method off the fault to extract information about Dc from strong-motion records due to ruptures propagating at subshear speeds. However, a reasonably accurate estimate of Dc in this rupture regime is only possible within a case-dependent narrow zone adjacent to the fault. The length of this zone, Rc, is comparable to the length of the fault cohesive zone where the breakdown process takes place, and approximately equal to 80% of the wavelength associated with the breakdown frequency (Cruz-Atienza et al., 2009). When the rupture propagates with supershear speeds, on the other hand, this energy is carried much farther away from the fault by Mach waves, in particular Rayleigh Mach-waves when rupture reaches the Earth’s surface. Here, we present a new approach to estimate Dc from strong-motion records containing Mach-waves (Cruz-Atienza and Olsen, 2010). First, we show that the method by Mikumo et al. is valid for supershear rupture propagation. This method is then used to estimate Dc via an asymptotic approximation of the slip and slip-rate time histories from Mach-waves recordings. Using 3D spontaneous rupture simulations we demonstrate that, for a visco-elastic half-space model, Dc can be estimated with an accuracy of 40% from Mach-waves that have propagated a distance of at least 3 km from the fault. The method is applied to estimate Dc for the 2002 Mw7.9 Denali, Alaska, earthquake (~1.5 m) and for the 1999 Mw7.6 Izmit, Turkey, earthquake (~1.7 m). REFERENCES: 1) Cruz-Atienza, V.M., K.B. Olsen, and L.A. Dalguer (2009). Estimation of the breakdown slip from strong-motion seismograms: insights from numerical experiments Bull. Seismol. Soc. Am., 99, 3454-3469, doi:10.1785/0120080330. 2) Cruz-Atienza, Víctor M. and Kim B. Olsen. Supershear Mach-Waves Expose the Fault Breakdown Slip, Tectonophysics (2010), doi:10.1016/j.tecto.2010.05.012. 3) Fukuyama, E., Mikumo T., 2007. Slip-weakening distance estimated at near-fault stations, Geophys. Res. Lett., 34, doi:10.1029/2006GL029203. 4) Mikumo, T., K.B. Olsen, E. Fukuyama, and Y. Yagi (2003). Stress-breakdown time and critical weakening slip inferred from the source time functions on earthquake faults, Bull. Seismol. Soc. Am. 93, 264-282.

Cruz-Atienza, V. M.; Olsen, K. B.

2010-12-01

251

Global strike-slip faults: Bounds from plate tectonics  

NASA Astrophysics Data System (ADS)

According to the tenets of plate tectonics, a transform fault is a strike-slip fault along which neither convergence nor divergence occurs. Analysis of global plate motion data indicates that the only true transform faults are the strike-slip faults that offset segments of mid-ocean ridges. Thus, many of Earth's major strike-slip fault systems are not true transform faults as they accommodate large components of oblique convergence or oblique divergence. This is particularly true for several important ocean-continent systems such as the San Andreas, the strike-slip systems bounding the northern and southern Caribbean plate, the Alpine fault system of New Zealand, the Anatolian fault system, and the Azores-Gibraltar-Alboran sea system. These strike-slip systems are commonly sites of large scale mountain building and basin formation. Here we examine the far-field constraints on the motions of the plates bounding several of these strike-slip systems using both conventional plate motion circuits and results from global positioning system and other space geodetic data. We pay particular attention to the San Andreas fault system in central and northern California, where the San Andreas system is part of the boundary between the Sierran microplate and the Pacific plate. Most of the fault system accommodates obliquely convergent motion, giving rise to the California Coast Range, but in the northern San Francisco Bay Area it is obliquely divergent, producing San Pablo Bay and a gap in the Coast Range that permits the Sierran watershed to drain to the Pacific through the Golden Gate.

Gordon, R. G.; Argus, D. F.

2006-12-01

252

Reduced Aftershock Productivity in Regions with Known Slow Slip Events  

NASA Astrophysics Data System (ADS)

Reduced aftershock activity has been observed in areas with high rates of aseismic slip, such as transform fault zones and some subduction zones. Fault conditions that could explain both of these observations include a low effective normal stress regime and/or a high temperature, semi-brittle/plastic rheology. To further investigate the possible connection between areas of aseismic slip and reduced aftershock productivity, we compared the mainshock-aftershock sequences in subduction zones where aseismic slip transients have been observed to those of adjacent (along-strike) regions where no slow slip events have been detected. Using the Advanced National Seismic System (ANSS) catalog, we counted aftershocks that occurred within 100 km and 14 days of 112 M>=5.0 slab earthquake mainshocks from January 1980 - July 2013, including 90 since January 2000, inside observed regions of detected slow slip: south central Alaska, Cascadia, the Nicoya Peninsula (Costa Rica), Guerrero (Mexico), and the North Island of New Zealand. We also compiled aftershock counts from 97 mainshocks from areas adjacent to each of these regions using the same criteria and over the same time interval. Preliminary analysis of these two datasets shows an aftershock triggering exponent (alpha in the ETAS model) of approximately 0.8, consistent with previous studies of aftershocks in a variety of tectonic settings. Aftershock productivity for both datasets is less than that of continental earthquakes. Contrasting the two datasets, aftershock productivity inside slow slip regions is lower than in adjacent areas along the same subduction zone and is comparable to that of mid-ocean ridge transform faults.

Collins, G.; Mina, A.; Richardson, E.; McGuire, J. J.

2013-12-01

253

Coulombic wall slip of concentrated soft-particle suspensions  

NASA Astrophysics Data System (ADS)

The coefficients of friction of concentrated soft-particle suspensions (tomato paste and a microgel suspension) were measured as a function of the slip velocity for a number of substrates. The data are interpreted using a micro-elastohydrodynamic model that is consistent with significant bulk frictional dissipation and an increase in the number of particle-wall contacts with increasing normal stress. The origin of the Coulombic slip, which has not been observed previously for pastes, is ascribed to the sensitivity of the lubricating film thickness.

Adams, Michael; Liu, Wei; Zhang, Zhibing; Fryer, Peter

2013-06-01

254

Resonant slow fault slip in subduction zones forced by climatic load stress  

NASA Astrophysics Data System (ADS)

Global Positioning System (GPS) measurements at subduction plate boundaries often record fault movements similar to earthquakes but much slower, occurring over timescales of ~1week to ~1year. These `slow slip events' have been observed in Japan, Cascadia, Mexico, Alaska and New Zealand. The phenomenon is poorly understood, but several observations hint at the processes underlying slow slip. Although slip itself is silent, seismic instruments often record coincident low-amplitude tremor in a narrow (1-5cycles per second) frequency range. Also, modelling of GPS data and estimates of tremor location indicate that slip focuses near the transition from unstable (`stick-slip') to stable friction at the deep limit of the earthquake-producing seismogenic zone. Perhaps most intriguingly, slow slip is periodic at several locations, with recurrence varying from 6 to 18months depending on which subduction zone (or even segment) is examined. Here I show that such periodic slow fault slip may be a resonant response to climate-driven stress perturbations. Fault slip resonance helps to explain why slip events are periodic, why periods differ from place to place, and why slip focuses near the base of the seismogenic zone. Resonant slip should initiate within the rupture zone of future great earthquakes, suggesting that slow slip may illuminate fault properties that control earthquake slip.

Lowry, Anthony R.

2006-08-01

255

Quantitative description and analysis of earthquake-induced deformation zones along strike-slip and dip-slip faults  

NASA Astrophysics Data System (ADS)

Deformation zones are belts of high strains that can occur at the ground surface centered or asymmetrical relative to the trace of an earthquake fault and can range in width from a meter or two up to hundreds of meters. In order to minimize damage to engineering structures within deformation zones one needs to be able to determine the characteristics of the deformation zone. We develop an elastic-plastic model of fault-slip propagation to explain formation of deformation zones and estimate certain parameters to characterize deformation zones. Our theory suggests the ratio of widths of deformation zones in hanging wall and foot wall of dipping faults should be controlled by fault dip angle and the kind of fault—the relations are different for strike-slip and dip-slip faults. Also, the total width of the deformation zone normalized with fault slip during the earthquake should be determined by the dip angle, the exponent of the yield condition, and the kind of fault. The theoretical parameters measured for deformation zones along the strike-slip, Duzce-Bolu fault at Kaynasli, Turkey and two deformation zones along the Chi-Chi thrust fault, Taiwan agree well with parameters determined from geophysical and geological sources. The theoretical model also indicates that the Winnetka strain belts related to the 1994 Northridge earthquake could have formed above a previously unknown blind fault at Winnetka; the analysis suggests that the Winnetka fault is a normal, dip-slip fault, dipping ~54°S with a fault-tip depth of approximately 360 m.

Johnson, A. M.; Huang, W.

2009-12-01

256

Quantitative description and analysis of earthquake-induced deformation zones along strike-slip and dip-slip faults  

NASA Astrophysics Data System (ADS)

Deformation zones are belts of high strains that can occur at the ground surface centered or asymmetrical relative to the trace of an earthquake fault and can range in width from a meter or two up to hundreds of meters. In order to minimize damage to engineering structures within deformation zones one needs to be able to determine the characteristics of the deformation zones. We develop an elastic-plastic model of fault slip propagation to explain formation of deformation zones and estimate certain parameters to characterize deformation zones. Our theory suggests the ratio of widths of deformation zones in hanging wall and footwall of dipping faults should be controlled by fault dip angle and the kind of fault; the relations are different for strike-slip and dip-slip faults. Also, the total width of the deformation zone normalized with fault slip during the earthquake should be determined by the dip angle, the exponent of the yield condition, and the kind of fault. The theoretical parameters measured for deformation zones along the strike-slip Düzce-Bolu fault at Kayna?l?, Turkey, and two deformation zones along the Chi-Chi thrust fault, Taiwan, agree well with parameters determined from geophysical and geological sources. The theoretical model also indicates that the Winnetka strain belts related to the 1994 Northridge earthquake could have formed above a previously unknown blind fault at Winnetka; the analysis suggests that the Winnetka fault is a normal, dip-slip fault, dipping ˜54°S with a fault tip depth of ˜360 m.

Huang, Wen-Jeng; Johnson, Arvid M.

2010-03-01

257

Investigation of joint disease  

Microsoft Academic Search

The role of nuclear medicine in the diagnosis and management of the major arthropathies is critically reviewed, with particular reference to osteoarthritis, rheumatoid and similar forms of arthritis, ankylosing spondylitis, non-specific back pain, gout, the neuropathic joint, avascular necrosis, infection and the consequences of prosthetic joint insertion. Attention is drawn both to practical applications and deficiencies in current techniques and

M. V. Merrick

1992-01-01

258

Joint Newspaper Operating Agreements.  

ERIC Educational Resources Information Center

The number of competing daily newspapers in American cities has dwindled until only about 50 cities boast two papers. Of the newspapers in those cities, 23 now maintain separate editorial operations but have joint printing, advertising, and circulation departments. The concept of joint operation is 50 years old, dating from the Depression years…

Parsons, Marie

259

Stick-slip instabilities and shear strain localization in amorphous materials Eric G. Daub  

E-print Network

on stick-slip instabilities, which are responsible for earthquake slip on seismic faults, noise from automobile brakes and tires, music from a violin, and excessive wear on frictional interfaces in machinery

Carlson, Jean

260

Charge-Related SQUID and Tunable Phase-Slip Flux Qubit  

NASA Astrophysics Data System (ADS)

A phase-slip flux qubit, exactly dual to a charge qubit, is composed of a superconducting loop interrupted by a phase-slip junction. We propose a tunable phase-slip flux qubit by replacing the phase-slip junction with a charge-related superconducting quantum interference device (SQUID) consisting of two phase-slip junctions connected in series with a superconducting island. This charge-SQUID acts as an effective phase-slip junction controlled by the applied gate voltage and can be used to tune the energy-level splitting of the qubit. In addition, we show that a large inductance inserted in the loop can reduce the inductance energy and consequently suppress the dominating flux noise of the phase-slip flux qubit. This enhanced phase-slip flux qubit is exactly dual to a transmon qubit.

Zhao, Hu; Li, Tie-Fu; Liu, Jian-She; Chen, Wei

2014-03-01

261

MISR JOINT_AS Data  

Atmospheric Science Data Center

Joint Aerosol Product (JOINT_AS) The MISR Level 3 Products are global or regional ... field campaigns at daily and monthly time scales. The Joint Aerosol product provides a monthly global statistical summary of MISR ...

2014-07-21

262

JOINT APPENDICES 2005 BUILDING ENERGY  

E-print Network

JOINT APPENDICES CALIFORNIA ENERGY COMMISSION for the 2005 BUILDING ENERGY EFFICIENCY STANDARDS, Deputy Director ENERGY EFFICIENCY AND DEMAND ANALYSIS DIVISION #12;NOTICE This version of the 2005 Joint. #12;TABLE OF CONTENTS I. Joint Appendix I ­ Glossary ........................................... Pages

263

Joint Infection (Beyond the Basics)  

MedlinePLUS

... medications. Artificial joint infection symptoms — People who develop infections immediately after joint replacement surgery typically have pain, redness, and swelling at the joint or drainage from the wound. Those who develop infections later usually notice a ...

264

Slip-based tire-road friction estimation  

Microsoft Academic Search

An approach to estimate the tire-road friction during normal drive using only the wheel slip, that is, the relative difference in wheel velocities, is presented. The driver can be informed about the maximum friction force and be alarmed for sudden changes. Friction-related parameters are estimated using only signals from standard sensors in a modern car. An adaptive estimator is presented

Fredrik Gustafsson

1997-01-01

265

Slip Diffusion and Lévy Flights of an Adsorbed Gold Nanocluster  

Microsoft Academic Search

Anomalous diffusion of a gold nanocrystal Au140, adsorbed on the basal plane of graphite, exhibiting Lévy-type power-law flight-length and sticking-time distributions, is predicted through extensive molecular dynamics simulations. An atomistic collective slip-diffusion mechanism is proposed and analyzed.

W. D. Luedtke; Uzi Landman

1999-01-01

266

Dynamic Action Units Slip in Speech Production Errors  

ERIC Educational Resources Information Center

In the past, the nature of the compositional units proposed for spoken language has largely diverged from the types of control units pursued in the domains of other skilled motor tasks. A classic source of evidence as to the units structuring speech has been patterns observed in speech errors--"slips of the tongue". The present study reports, for…

Goldstein, Louis; Pouplier, Marianne; Chen, Larissa; Saltzman, Elliot; Byrd, Dani

2007-01-01

267

Stick-Slip Behavior of Torque Converter Clutch  

Microsoft Academic Search

The chief objective of this paper is to study the non-linear behavior of torque converter clutch within the context of an automotive drivetrain. An analytical procedure to determine the pure stick to stick-slip motions is developed based on the linear system analysis. This procedure can efficiently and accurately identify the frequency ranges where linear or non -linear studies are needed.

Chengwu Duan; Rajendra Singh

2005-01-01

268

Transient Analysis of Slip Flow and Heat Transfer in Microchannels  

Microsoft Academic Search

Hybrid analytical-numerical solutions for transient flow and transient convective heat transfer within microchannels are presented. Analytical solutions for flow transients in microchannels are obtained by making use of the integral transform approach. The proposed model involves the transient fully developed flow equation for laminar regime and incompressible flow with slip at the walls in simple channel geometries. The solution is

F. V. Castellões; C. R. Cardoso; P. Couto; R. M. Cotta

2007-01-01

269

Slip-flow heat transfer in rectangular microchannels  

Microsoft Academic Search

Laminar slip-flow forced convection in rectangular microchannels is studied analytically by applying a modified generalized integral transform technique to solve the energy equation, assuming hydrodynamically fully developed flow. Results are given in terms of the fluid mixed mean temperature, and both local and fully developed mean Nusselt numbers. Heat transfer is found to increase, decrease, or remain unchanged, compared to

Shiping Yu; Timothy A. Ameel

2001-01-01

270

Role of stepovers in strike-slip tectonics  

SciTech Connect

It is shown that the key to understanding the tectonic complexity of large strike-slip fault systems is fault stepovers. Depending on the sense of stepover, discontinuities along the strike of faults result in pull-apart basins and push-up ranges, several examples of which are presented to illustrate the associated structures and their complexities. Discountinuities along the dip direction of strike-slip faults are poorly known because of the lack of field observations. Data from seismicity, however, can be used to fill this gap. One example of such en echelon fault geometry is found along the Calaveras fault, California. It is inferred that stepovers along the dip direction of strike-slip faults may produce secondary strike-slip faulting on inclined planes connecting the en echelon segments of the major fault. As the amount of overlap increases, features similar to pull-apart basins or push-up ranges are expected to occur. Caused for the formation of discontinuities and control of the sense of stepover are not well known. Some possible factors are: spatial variability of the coefficient of friction, spatially variable elastic moduli, high pore pressure, and interaction between neighboring faults in an array of faults. The first two would give rise to both senses of stepover, whereas the last two lead only to one sense of stepover, which induces pull-apart basins.

Aydin, A.

1984-04-01

271

Micro-Vibration-Based Slip Detection in Tactile Force Sensors  

PubMed Central

Tactile sensing provides critical information, such as force, texture, shape or temperature, in manipulation tasks. In particular, tactile sensors traditionally used in robotics are emphasized in contact force determination for grasping control and object recognition. Nevertheless, slip detection is also crucial to successfully manipulate an object. Several approaches have appeared to detect slipping, the majority being a combination of complex sensors with complex algorithms. In this paper, we deal with simplicity, analyzing how a novel, but simple, algorithm, based on micro-vibration detection, can be used in a simple, but low-cost and durable, force sensor. We also analyze the results of using the same principle to detect slipping in other force sensors based on flexible parts. In particular, we show and compare the slip detection with: (i) a flexible finger, designed by the authors, acting as a force sensor; (ii) the finger torque sensor of a commercial robotic hand; (iii) a commercial six-axis force sensor mounted on the wrist of a robot; and (iv) a fingertip piezoresistive matrix sensor. PMID:24394598

Fernandez, Raul; Payo, Ismael; Vazquez, Andres S.; Becedas, Jonathan

2014-01-01

272

Unified formulation for analysis of slopes with general slip surface  

SciTech Connect

The general availability of computers has provided efficient means of assessing the stability of slopes using several analytical methods. However, the increased use of computers coupled with a lack of unified presentation of the various methods sometimes leads to conflicting results. It is shown that the current analytical methods can be grouped into three categories based on the hypotheses used to describe the internal forces, namely: (1) the direction of the internal forces; (2) the height of the line of thrust; and (3) the shape of the distribution function of the internal shear forces. An analytical framework incorporating this idea is presented to facilitate and unify slope stability analysis with general slip surfaces. The study is a generalization of earlier work performed by Espinoza et al. for circular slip surfaces. The framework incorporates most current methods of analysis. The analytical model is implemented in a computer program. The program was used to study several case examples. On this basis, key issues associated with the influence of the internal shear forces on the factor of safety, for both circular and general slip failure surfaces, are discussed. It appears that for circular failure surfaces, even with heterogeneous soil stratigraphy the factor of safety is not affected by the choice of a particular hypothesis. On the contrary, for general slip surfaces this choice may significantly affect the results.

Espinoza, R.D.; Bourdeau, P.L. (Purdue Univ., West Lafayette, IN (United States). School of Civil Engineering); Muhunthan, B. (Washington State Univ., Pullman, WA (United States). Dept. of Civil and Environmental Engineering)

1994-07-01

273

On the elementary relation between pitch, slip, and propulsive efficiency  

NASA Technical Reports Server (NTRS)

The author examines the current theory on the importance of reducing slip in airplane propellers. The author feels an exaggerated importance is attached to this supposition and feels that the increase in friction by an increase in propeller area or number of revolutions can't be discounted.

Froude, W

1920-01-01

274

Seismic slip, segmentation, and the Loma Prieta Earthquake  

Microsoft Academic Search

We have plotted the cumulative seismic slip projected onto a vertical plane for earthquakes occurring during the last 20 years along 210 km of the San Andreas fault that includes the section that moved in the Loma Prieta earthquake. These plots illustrate the differences in depth and character of the seismicity between the locked and creeping portions of the fault

Geoffrey C. P. King; Allan G. Lindh; David H. Oppenheimer

1990-01-01

275

Seismic slip, segmentation, and the Loma Prieta earthquake  

Microsoft Academic Search

The authors have plotted the cumulative seismic slip projected onto a vertical plane for earthquakes occurring during the last 20 years along 210 km of the San Andreas fault that includes the section that moved in the Loma Prieta earthquake. These plots illustrate the differences in depth and character of the seismicity between the locked and creeping portions of the

Geoffrey C. P. King; Allan G. Lindh; David H. Oppenheimer

1990-01-01

276

Chaotic mixing in a planar, curved channel using periodic slip  

E-print Network

We propose a novel strategy for designing chaotic micromixers using curved channels confined between two flat planes. The location of the separatrix between the Dean vortices, induced by centrifugal force, is dependent on the location of the maxima of axial velocity. An asymmetry in the axial velocity profile can change the location of the separatrix. This is achieved physically by introducing slip alternatingly at the top and bottom walls. This leads to streamline crossing and Lagrangian chaos. An approximate analytical solution of the velocity field is obtained using perturbation theory. This is used to find the Lagrangian trajectories of fluid particles. Poincare sections taken at periodic locations in the axial direction are used to study the extent of chaos. The extent of mixing, for low slip and low Reynolds numbers, is shown to be greater when Dean vortices in adjacent half cells are counter-rotating. Wide channels are observed to have much better mixing than tall channels; an important observation not made for separatrix flows till now. Eulerian indicators are used to gauge the extent of mixing with varying slip length and it is shown that an optimum slip length exists which maximizes the mixing in a particular geometry.

P. Garg; J. R. Picardo; S. Pushpavanam

2014-11-24

277

Wear studies made of slip rings and gas bearing components  

NASA Technical Reports Server (NTRS)

Neutron activation analysis techniques were employed for the study of the wear and performance characteristics of slip ring and rotor assemblies and of the problems arising from environmental conditions with special reference to surface contamination. Results showed that the techniques could be successfully applied to measurement of wear parameters.

Furr, A. K.

1967-01-01

278

An Analysis of Strain Accumulation on a Strike Slip Fault  

Microsoft Academic Search

An analysis of strain accumulation on a strike slip fault is given. The fault between two lithospheric plates is assumed to be locked tb a finite depth; owing to plastic flow the fault is free to slide at greaier depths. The base of each plate is also a free boundary. The periodic stress accumulation andtress release associated with the elastic

D. L. Turcotte; D. A. Spence

1974-01-01

279

Slip Surface Localization in Wireless Sensor Networks for Landslide Prediction  

E-print Network

Slip Surface Localization in Wireless Sensor Networks for Landslide Prediction Andreas Terzis Applied Physics Lab Johns Hopkins University Laurel, MD 20723 I-Jeng.Wang@jhuapl.edu ABSTRACT A landslide understood, prediction of landslides has been hin- dered thus far by the lack of field measurements over

Amir, Yair

280

Analysing earthquake slip models with the spatial prediction comparison test  

NASA Astrophysics Data System (ADS)

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.

Zhang, Ling; Mai, P. Martin; Thingbaijam, Kiran K. S.; Razafindrakoto, Hoby N. T.; Genton, Marc G.

2015-01-01

281

Boundary slip in Newtonian liquids: a review of experimental studies  

Microsoft Academic Search

For several centuries fluid dynamics studies have relied upon the assumption that when a liquid flows over a solid surface, the liquid molecules adjacent to the solid are stationary relative to the solid. This no-slip boundary condition (BC) has been applied successfully to model many macroscopic experiments, but has no microscopic justification. In recent years there has been an increased

Chiara Neto; Drew R. Evans; Elmar Bonaccurso; Hans-Jürgen Butt; Vincent S. J. Craig

2005-01-01

282

Slip modelling and aided inertial navigation of an LHD  

Microsoft Academic Search

This paper describes the theoretical development and experimental evaluation of a guidance system for an autonomous load, haul and dump truck (LHD) for use in underground mining. The particular contributions of this paper are in designing the navigation system to be able to cope with vehicle slip in rough uneven terrain using information from an inertial navigation system (INS) and

S. Scheding; G. Dissanayake; E. Nebot; H. Durrant-Whyte

1997-01-01

283

Regional Slip Tendency Analysis of the Great Basin Region  

DOE Data Explorer

- The resulting along?fault and fault?to?fault variation in slip or dilation potential is a proxy for along fault and fault?to?fault variation in fluid flow conduit potential. Stress Magnitudes and directions were calculated across the entire Great Basin. Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson?Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005). The minimum horizontal stress direction (Shmin) was contoured, and spatial bins with common Shmin directions were calculated. Based on this technique, we subdivided the Great Basin into nine regions (Shmin <070, 070140). Slip and dilation tendency were calculated using 3DStress for the faults within each region using the mean Shmin for the region. Shmin variation throughout Great Basin are shown on Figure 3. For faults within the Great Basin proper, we applied a normal faulting stress regime, where the vertical stress (sv) is larger than the maximum horizontal stress (shmax), which is larger than the minimum horizontal stress (sv>shmax>shmin). Based on visual inspection of the limited stress magnitude data in the Great Basin, we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46. These values are consistent with stress magnitude data at both Dixie Valley (Hickman et al., 2000) and Yucca Mountain (Stock et al., 1985). For faults within the Walker Lane/Eastern California Shear Zone, we applied a strike?slip faulting stress, where shmax > sv > shmin. Upon visual inspection of limited stress magnitude data from the Walker Lane and Eastern California Shear zone, we chose values such that SHmin/SHmax = .46 and Shmin/Sv= .527 representative of the region. Results: The results of our slip and dilation tendency analysis are shown in Figures 4 (dilation tendency), 5 (slip tendency) and 6 (slip tendency + dilation tendency). Shmin varies from northwest to east?west trending throughout much of the Great Basin. As such, north? to northeast?striking faults have the highest tendency to slip and to dilate, depending on the local trend of shmin. These results provide a first order filter on faults and fault systems in the Great Basin, affording focusing of local?scale exploration efforts for blind or hidden geothermal resources.

Faulds, James E.

284

Steady-state friction during earthquake slip: Fact or myth?  

NASA Astrophysics Data System (ADS)

The rupture front of an earthquake propagates along a fault while activating countless patches. Each patch undergoes intense deformation variations from rest before the front developing to acceleration, weakening, deceleration and healing. While it is unlikely that steady-state stage would materialize in such history during rise-time, the modeling of earthquake rupture is almost exclusively based on friction measurements conducted under steady-state condition. An alternative approach is presented here. Experimentally, the friction strength of a fault is determined by its relations to the slip-distance and slip-velocity, and these relations are implicitly assumed to be rock properties. Recent observations however, show that these relations strongly depend on the slip-velocity history. Consider three styles of velocity loading: Impact (abrupt increase followed by gradual deceleration), constant (steady velocity), and ramp (gradual increase followed by abrupt deceleration). Chang et al. (2012) found that running the same sample (Sierra White granite) under different velocity loading yielded different relations: Impact loading had much shorter critical weakening distance (0.03 m for impact and 1-3 m for constant), and drastic dynamic weakening under high velocity (V > 0.1 m/s), whereas dynamic strengthening was observed under V > 0.05 m/s for constant velocity. Similar behavior was recently observed for an experimental fault made of syenite under impact and ramp loading. Further, under impact velocity, the period of velocity increase (acceleration) overlaps the period of fault weakening. This correlation is not unique and similar weakening-acceleration associations were reported in stick-slip experiments (Ohnaka & Yamashita, 1989), rotary shear (Goldsby & Tullis, 2011), and Kolsky impact shear experiments (Yuan & Prakash, 2008). These studies greatly differ from each other in slip distance, normal stress, acceleration, and slip-velocities with the outstanding commonality of impact velocity loading. Analyses of seismic data (e.g., Tinti et al., 2005) and numerical simulation of earthquake rupture (e.g., Day et al., 2005), indicate that the early slip of a fault patch is characterized by intense acceleration. Based on these experimental and modeling results we conclude that dynamic frictional strength, which is determined in steady-state experiments, is not necessarily relevant to fault strength during earthquakes. More relevant experiments should be conducted under impact loading that better fits high velocity rupture propagation.

Reches, Zeev; Chang, Jefferson

2013-04-01

285

Global seismicity characteristics of subduction-to-strike-slip transitions  

NASA Astrophysics Data System (ADS)

There are at least 30 major plate boundary segments worldwide where the plate boundary changes from subduction to strike-slip; these include six triple junctions and 24 two-plate boundaries. This study investigates earthquake seismicity in the 24 two-plate subduction-to-strike-slip transition (SSST) regions by utilizing recently published earthquake relocations, ternary diagrams of focal mechanisms, and moment rate calculations. To facilitate cross-regional comparisons, we categorize the geometry of SSST plate boundaries in terms of (1) their radius of curvature, (2) their sense of curvature, that is, whether they are convex or concave as viewed from the downgoing plate, and (3) their tectonic complexity, that is, the variability of crustal thickness and the segmentation of the plate boundary trace. We observe three main trends in SSST regions: (1) there is a conspicuous scarcity of strike-slip earthquakes along plate boundary segments that plate motion models indicate are strike-slip boundaries; (2) in these apparent strike-slip segments, both the rate of occurrence of earthquakes of any kind and the moment release rate are low compared to adjacent subduction segments; and (3) there were few observable differences in seismicity between convex and concave boundaries. The observation that transform zones exhibit moment rate deficiencies, that is, have few large-magnitude earthquakes in the historical record, may have important implications for seismic hazard assessment in SSST regions. In particular, is motion along these boundaries aseismic with little seismic hazard, or is motion expressed in very large magnitude, infrequent, but potentially devastating earthquakes? In at least three such regions, New Zealand, the Philippines, and the Dominican Republic, paleoseismic evidence and the historical record of seismicity suggest that very large, infrequent earthquakes do occur.

Bilich, Andria; Frohlich, Cliff; Mann, Paul

2001-09-01

286

Supershear Mach-waves expose the fault breakdown slip  

NASA Astrophysics Data System (ADS)

Mikumo et al. (2003) showed that it is possible to estimate the breakdown slip ( Dc) as the slip at the time of the peak slip rate for rupture propagation with subshear speeds. Cruz-Atienza et al. (2009) later attempted to extend this method to extract information about Dc as the displacement at the time of the peak particle velocity from seismic strong-motion records. However, a reasonably accurate estimate of Dc was only possible in a narrow zone adjacent to the fault (typically on the order of hundreds of meters) due to the fast decay with distance from the fault of the seismic energy related to the stress breakdown process. When the rupture propagates with supershear-speeds, on the other hand, this energy is carried much farther away from the fault by Mach waves, in particular Rayleigh Mach waves when rupture reaches the Earth's surface (Dunham and Bhat, 2008). Here, we present a new approach to estimate Dc from strong-motion records containing Mach waves. First, we show that the method by Mikumo et al. is valid for supershear rupture propagation. This method is then used to estimate Dc via an asymptotic approximation of the slip and slip-rate time histories from the Mach waves. Using spontaneous rupture simulations we demonstrate that, for a visco-elastic half-space model, Dc can be estimated within an error of 40% from Mach waves that have propagated a distance of at least 3 km from the fault. The method is applied to estimate Dc for the 2002 Mw7.9 Denali, Alaska, earthquake (˜ 1.5 m) and for the 1999 Mw7.6 Izmit, Turkey, earthquake (˜ 1.7 m).

Cruz-Atienza, Víctor M.; Olsen, Kim B.

2010-10-01

287

JOINT ELECTRICAL & COMPUTER ENGINEERING AND  

E-print Network

JOINT ELECTRICAL & COMPUTER ENGINEERING AND PHYSICS COLLOQUIUM "Speckle Statistics, Coherence confirmation of the increase in the well- defined polarization state of the output radiation. In the joint

288

Three-dimensional analyses of slip distributions on normal fault arrays with consequences for fault scaling  

Microsoft Academic Search

Many fault arrays consist of echelon segments. Field data on ancient and active faults indicate that such segmented geometries have a pronounced effect on the distribution of fault slip. Outcrop measurements of slip on arrays of fault segments show that: (i) the point of maximum fault slip generally is not located at the centre of a fault segment; (ii) displacement

Emanuel J. M. Willemse; David D. Pollard; Atilla Aydin

1996-01-01

289

Very high cycle fatigue of copper: Evolution, morphology and locations of surface slip markings  

E-print Network

Very high cycle fatigue of copper: Evolution, morphology and locations of surface slip markings N cycle fatigue Persistent slip bands Grain boundaries Strain localization Fatigue limit The surfaces high cycle fatigue regime were investigated. The stress amplitude needed to form the early slip

Paris-Sud XI, Université de

290

Roughness Induced Boundary Slip in Microchannel Flows Christian Kunert and Jens Harting  

E-print Network

Roughness Induced Boundary Slip in Microchannel Flows Christian Kunert and Jens Harting Institute that the fluid velocity vx at the boundary (x 0) is proportional to the shear rate @v @x and the slip length #12 with vapor or gas nano bubbles leading to apparent slip [2,9]. Recently, Sbragaglia et al. applied the LB

Harting, Jens

291

Modeling of the effects of propagating thrust slip on pore pressures and implications for monitoring  

NASA Astrophysics Data System (ADS)

Recent observations at subduction zones and other environments have brought attention to the variety of slip processes along fault zones, including aseismic slip, slow slip, and very-low-frequency seismicity. Pore pressure records from monitoring wells have the potential to provide information on the nature of these slip processes. In this study, an analytical solution for strain due to fault slip is combined with fluid flow modeling to illustrate the effects of propagating fault slip on pore pressure records. Results indicate that propagating slip produces a distinct pore pressure record (as compared to a single slip event over the same interval) that is best observed with boreholes distributed in the direction of slip progression. For slip propagating at 100 m/day for 50 days, fluid flow does not significantly affect the pore pressure signal if hydraulic diffusivities are ? 0.001 m 2 s - 1 . Most clay- and silt-rich sediments would be expected to have significantly lower hydraulic diffusivities and thus should provide a good record of propagating slip. In contrast, sand-rich sediments or permeable basaltic crust would provide a poor record of propagating slip. Additional simulations examined the impact of high permeability within the fault zone and found it has little impact on pore pressure results. The model results provide insight on observation data from the Costa Rica and Nankai subduction zones.

Screaton, E. J.; Ge, S.

2007-06-01

292

Mixed linear-nonlinear fault slip inversion: Bayesian inference of model, weighting, and smoothing parameters  

Microsoft Academic Search

Studies utilizing inversions of geodetic data for the spatial distribution of coseismic slip on faults typically present the result as a single fault plane and slip distribution. Commonly the geometry of the fault plane is assumed to be known a priori and the data are inverted for slip. However, sometimes there is not strong a priori information on the geometry

J. Fukuda; K. M. Johnson

2009-01-01

293

Compactness vs. Smoothness: Methods for regularizing fault slip inversions with application to subduction zone earthquakes  

Microsoft Academic Search

We examine inversions of geodetic data for fault slip and discuss how inferred results are affected by choices of regularization. The final goal of any slip inversion is to enhance our understanding of the dynamics governing fault zone processes through kinematic descriptions of fault zone behavior at various temporal and spatial scales. Important kinematic observations include ascertaining whether fault slip

R. B. Lohman; M. Simons

2004-01-01

294

Stability and Uncertainty of Finite-Fault Slip Inversions: Application to the 2004 Parkfield, California, Earthquake  

E-print Network

aspects of the finite-fault slip inversion problem with different a priori model assumptions. We utilize used to solve the finite-fault slip inversion problem. For the Parkfield earthquake and the inversionStability and Uncertainty of Finite-Fault Slip Inversions: Application to the 2004 Parkfield

Larson, Kristine

295

Is there a discrepancy between geological and geodetic slip rates along the San  

E-print Network

Is there a discrepancy between geological and geodetic slip rates along the San Andreas Fault and Geophysics, University of Hawai`i at Mnoa, Honolulu, Hawaii, USA Abstract Previous inversions for slip rate between the geologic and geodetic slip rates along a few major fault segments. In this study, we use

Sandwell, David T.

296

An integrated perspective of the continuum between earthquakes and slow-slip phenomena  

USGS Publications Warehouse

The discovery of slow-slip phenomena has revolutionized our understanding of how faults accommodate relative plate motions. Faults were previously thought to relieve stress either through continuous aseismic sliding, or as earthquakes resulting from instantaneous failure of locked faults. In contrast, slow-slip events proceed so slowly that slip is limited and only low-frequency (or no) seismic waves radiate. We find that slow-slip phenomena are not unique to the depths (tens of kilometres) of subduction zone plate interfaces. They occur on faults in many settings, at numerous scales and owing to various loading processes, including landslides and glaciers. Taken together, the observations indicate that slowly slipping fault surfaces relax most of the accrued stresses through aseismic slip. Aseismic motion can trigger more rapid slip elsewhere on the fault that is sufficiently fast to generate seismic waves. The resulting radiation has characteristics ranging from those indicative of slow but seismic slip, to those typical of earthquakes. The mode of seismic slip depends on the inherent characteristics of the fault, such as the frictional properties. Slow-slip events have previously been classified as a distinct mode of fault slip compared with that seen in earthquakes. We conclude that instead, slip modes span a continuum and are of common occurrence.

Peng, Zhigang; Gomberg, Joan

2010-01-01

297

INCLUSION OF WHEEL SLIPS IN MOBILE ROBOT MODELING TO ENHANCE ROBOT SIMULATOR PERFORMANCE  

Microsoft Academic Search

Improving navigation performance of autonomous wheeled mobile robot (WMR) in a dynamic unstructured environment requires improved maneuverability. In such cases, the dynamics of wheel slip may violate the ideal no-slip kinematic constraints generally used to model nonholonomic WMR. In this paper, a new method is proposed to tackle the modeling inadequacy that arises when slip is neglected by including both

Naim Sidek

298

EXPERIMENTAL ANALYSIS OF GROUNDWATER FLOW THROUGH A LANDSLIDE SLIP SURFACE USING NATURAL AND ARTIFICIAL WATER  

E-print Network

EXPERIMENTAL ANALYSIS OF GROUNDWATER FLOW THROUGH A LANDSLIDE SLIP SURFACE USING NATURAL,Tric, Emmanuel,Bertrand, Catherine Mudry, Jacques Keywords: Hydromechanics, tracer test, landslides, slip surface measurements are conducted on a small landslide with a well known slip surface geometry. Outflow yields

Paris-Sud XI, Université de

299

The Effect of Slip Velocity on Saturation for Multiphase Condensing Mixtures in a PEM Fuel Cell  

E-print Network

The Effect of Slip Velocity on Saturation for Multiphase Condensing Mixtures in a PEM Fuel Cell in computed results reported in the fuel cell literature, but which has not yet received a satisfactory to treat the slip velocity between phases. Keywords: Condensation ­ Two Phase Flow ­ PEM Fuel Cell ­ Slip

Stockie, John

300

Pressure vessel flex joint  

NASA Technical Reports Server (NTRS)

An airtight, flexible joint is disclosed for the interfacing of two pressure vessels such as between the Space Station docking tunnel and the Space Shuttle Orbiter bulkhead adapter. The joint provides for flexibility while still retaining a structural link between the two vessels required due to the loading created by the internal/external pressure differential. The joint design provides for limiting the axial load carried across the joint to a specific value, a function returned in the Orbiter/Station tunnel interface. The flex joint comprises a floating structural segment which is permanently attached to one of the pressure vessels through the use of an inflatable seal. The geometric configuration of the joint causes the tension between the vessels created by the internal gas pressure to compress the inflatable seal. The inflation pressure of the seal is kept at a value above the internal/external pressure differential of the vessels in order to maintain a controlled distance between the floating segment and pressure vessel. The inflatable seal consists of either a hollow torus-shaped flexible bladder or two rolling convoluted diaphragm seals which may be reinforced by a system of straps or fabric anchored to the hard structures. The joint acts as a flexible link to allow both angular motion and lateral displacement while it still contains the internal pressure and holds the axial tension between the vessels.

Kahn, Jon B. (inventor)

1992-01-01

301

Slip and Dilation Tendency Analysis of the Patua Geothermal Area  

SciTech Connect

Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids. The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface: Ts = ? / ?n (Morris et al., 1996). Dilation tendency is defined by the stress acting normal to a given surface: Td = (?1-?n) / (?1-?3) (Ferrill et al., 1999). Slip and dilation were calculated using 3DStress (Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential. Stress Magnitudes and directions Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Slip and dilation tendency analysis for the Patua geothermal system was calculated based on faults mapped in the Hazen Quadrangle (Faulds et al., 2011). Patua lies near the margin between the Basin and Range province, which is characterized by west-northwest directed extension and the Walker Lane province, characterized by west-northwest directed dextral shear. As such, the Patua area likely has been affected by tectonic stress associated with either or both of stress regimes over geologic time. In order to characterize this stress variation we calculated slip tendency at Patua for both normal faulting and strike slip faulting stress regimes. Based on examination of regional and local stress data (as explained above) we applied at shmin direction of 105 to Patua. Whether the vertical stress (sv) magnitude is larger than ...

Faulds, James E.

2013-12-31

302

Analysis of the slow slip events of Guerrero, Mexico: implications for numerical modeling.  

NASA Astrophysics Data System (ADS)

Guerrero, in Mexico, is one of the subduction zones where long term slow slip events (SSEs) have been observed recurrently. Understanding the mechanics of these events is important to determine their role in the seismic cycle. SSEs in Guerrero have been found to have the same characteristics, along the interface of subduction, as classical earthquakes but with much longer slip time (around a year) and lower stress drop (0.1 MPa). We investigate the slip models of the Guerrero SSEs of 2006 and 2009 (Radiguet et al., JGR 2012). The kinematic slip models have been determined by inversion of GPS time series using two different methods. From these slip histories, the constitutive relation between stress and slip (or slip rate) on each subfault is determined. Analytical Green functions are used to calculate the shear stress in a homogeneous, elastic, isotropic medium. Whatever the kinematic slip modeling method used, a clear slip weakening law can be retrieved over the whole slipping area. While some spatial variation in the parameters of the slip weakening law is observed, a mean value of about 0.1 m for the slip weakening distance and 2.5 kJ/m2 for the fracture energy can be extracted on each subfault. Moreover the slip-weakening rate seems quite homogeneous (around 1 MPa/m), and this is roughly the same as the value found in coseismic processes. The yield stress is of the order of 0.01 MPa, a low value compared to a stress drop of 0.1 MPa. The stress-slip rate relationship presents a loop trajectory coherent with the one observed in classical earthquakes. The results of these analyses are used to numerically model the Guerrero SSEs. The aim is to reproduce the slip pattern using the mechanical laws determined in the study of the slip model. If a simple slip weakening law, with parameters found above, is used, we observe a rapid progress of the crack-like slip area. This is different from the observation of the migration of localized slip. So a slowing mechanism (healing) must be introduced in addition to the slip weakening law. A pseudo-dynamic model is developed, supposing a fully plastic fault strengthening with a prefixed slip distance.

Maury, Julie; Aochi, Hideo; Radiguet, Mathilde

2014-05-01

303

First metatarsophalangeal joint arthrodesis.  

PubMed

Arthrodesis of the first metatarsophalangeal joint (MTPJ) is used primarily for end-stage hallux rigidus whereby pain, crepitus, and limitation of motion is noted at the joint. Arthrodesis at the first MTPJ also has it uses as a primary procedure for rheumatoid arthritis when severe deformity is present, as well as for salvage procedures for failed joint arthroplasties with or without implant, fractures with intra-articular extension, avascular necrosis, and infection management. A first MTPJ arthrodesis should provide stable fixation, attain suitable positioning for a reasonable gait, maintain adequate length, and create a stable platform for a plantigrade foot type. PMID:22243568

Rajczy, Robert M; McDonald, Patrick R; Shapiro, Howard S; Boc, Steven F

2012-01-01

304

Compliant Joints For Robots  

NASA Technical Reports Server (NTRS)

Compliant joints devised to accommodate misalignments of tools and/or workpieces with respect to robotic manipulators. Has characteristics and appearance of both universal-joint and cable-spring-type flexible shaft coupling. Compliance derived from elastic properties of short pieces of cable. Compliance of joint determined by lengths, distances between, relative orientations, thickness of strands, number of strands, material, amount of pretwist, and number of short pieces of cable. Worm-drive mechanism used to adjust lengths to vary compliance as needed during operation.

Kerley, James J., Jr.

1990-01-01

305

Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie Bar, & Diagonal Brace Joint Detail; Chord, Tie Bar, & Crossbracing Joint Detail - Medora Bridge, Spanning East Fork of White River at State Route 235, Medora, Jackson County, IN

306

Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area  

SciTech Connect

Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids. The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface: Ts = ? / ?n (Morris et al., 1996). Dilation tendency is defined by the stress acting normal to a given surface: Td = (?1-?n) / (?1-?3) (Ferrill et al., 1999). Slip and dilation were calculated using 3DStress (Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential. Stress Magnitudes and directions Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Slip and dilation tendency for the Tuscarora geothermal field was calculated based on the faults mapped Tuscarora area (Dering, 2013). The Tuscarora area lies in the Basin and Range Province, as such we applied a normal faulting stress regime to the Tuscarora area faults, with a minimum horizontal stress direction oriented 115, based on inspection of local and regional stress determinations, as explained above. Under these stress conditions north-northeast striking, steeply dipping fault segments have the highest dilation tendency, while north-northeast striking 60° dipping fault segments have the highest tendency to slip. Tuscarora is defined by a left-step in a major north- to-north northeast striking, west-dipping range-bounding normal fault system. Faults within the broad step define an anticlinal accommodation zone...

Faulds, James E.

2013-12-31

307

Joint Special Operations University  

E-print Network

The Joint Special Operations University (JSOU) provides its publications to contribute toward expanding the body of knowledge about joint special operations. JSOU publications advance the insights and recommendations of national security professionals and the Special Operations Forces (SOF) students and leaders for consideration by the SOF community and defense leadership. JSOU is the educational component of the United States Special Operations Command (USSOCOM), MacDill Air Force Base, Florida. The JSOU mission is to educate SOF executive, senior, and intermediate leaders and selected other national and international security decision makers, both military and civilian, through teaching, outreach, and research in the science and art of joint special operations. JSOU provides education to the men and women of SOF and to those who enable the SOF mission in a joint and interagency environment. JSOU conducts research through its Strategic Studies Department where

Brian A. Maher; Ed. D; William S. Wildrick; U. S. Navy; Ret Resident; Senior Fellows; John B. Alexander; Roby C. Barrett, Ph.D.; Joseph D. Celeski; Chuck Cunningham

308

Joint fluid Gram stain  

MedlinePLUS

Gram stain of joint fluid ... result means no bacteria are present on the Gram stain. Note: Normal value ranges may vary slightly ... Abnormal results mean bacteria were seen on the Gram stain. This may be a sign of a ...

309

Temporomandibular Joint Disorders  

MedlinePLUS Videos and Cool Tools

... jaw joint. TMJ disorders can cause headaches, ear pain, bite problems, clicking sounds, locked jaws, and other ... three main categories: Muscle Disorders These disorders include pain in the muscles that control jaw function, as ...

310

New plastic joints for plastic orthoses  

Microsoft Academic Search

Plastic joints for orthoses have more advantages than metal joints. They are lightweight, noiseless comfortable to use, rust proof, corrosion free, and radiolucent. Two types of plastic joints were developed by the authors, one for the ankle joint and the other for the knee joint, elbow joint or hip joint. Polypropylene was chosen as the joint material because of its

H. WATANABE; T. KUTSUNA; H. MORINAGA; T. OKABE

311

Use of two-dimensional transmission photoelastic models to study stresses in double-lap bolted joints  

NASA Technical Reports Server (NTRS)

The stress distribution in two hole connectors in a double lap joint configuration was studied. The following steps are described: (1) fabrication of photoelastic models of double lap double hole joints designed to determine the stresses in the inner lap; (2) assessment of the effects of joint geometry on the stresses in the inner lap; and (3) quantification of differences in the stresses near the two holes. The two holes were on the centerline of the joint and the joints were loaded in tension, parallel to the centerline. Acrylic slip fit pins through the holes served as fasteners. Two dimensional transmission photoelastic models were fabricated by using transparent acrylic outer laps and a photoelastic model material for the inner laps. It is concluded that the photoelastic fringe patterns which are visible when the models are loaded are due almost entirely to stresses in the inner lap.

Hyer, M. W.; Liu, D. H.

1981-01-01

312

Bullet in Hip Joint  

PubMed Central

Recently, hip arthroscopy has become more popular in the diagnosis and extraction of intraarticular foreign bodies compared to open surgery. If a foreign object such as a bullet is not extracted from the hip joint, it may cause mechanical arthritis, infection and systemic lead toxicity. We present the arthroscopic excision of a bullet from the hip joint of a 33-year-old male patient who sustained a gunshot injury.

Kaya, Ibrahim; Ugras, Akin; Saglam, Necdet; Sungur, Ibrahim; Cetinus, Ercan

2013-01-01

313

Competing Research Joint Ventures  

Microsoft Academic Search

Research and development (R&D) competition among firms has recently been extended to R&D competition involving research joint ventures. It was previously shown that in an industry conducting cost-reducing R&D followed by competition in the product market, if all firms both fully share R&D information and coordinate investments to maximize joint profits, final products prices are lower, and firms' profits are

Morton I. Kamien; Israel Zang

1993-01-01

314

Self-healing slip pulses in dynamic rupture models due to velocity-dependent strength  

USGS Publications Warehouse

Seismological observations of short slip duration on faults (short rise time on seismograms) during earthquakes are not consistent with conventional crack models of dynamic rupture and fault slip. In these models, the leading edge of rupture stops only when a strong region is encountered, and slip at an interior point ceases only when waves from the stopped edge of slip propagate back to that point. In contrast, some seismological evidence suggests that the duration of slip is too short for waves to propagate from the nearest edge of the ruptured surface, perhaps even if the distance used is an asperity size instead of the entire rupture dimension. What controls slip duration, if not dimensions of the fault or of asperities? In this study, dynamic earthquake rupture and slip are represented by a propagating shear crack. For all propagating shear cracks, slip velocity is highest near the rupture front, and at a small distance behind the rupture front, the slip velocity decreases. As pointed out by Heaton (1990), if the crack obeys a negative slip-rate-dependent strength relation, the lower slip velocity behind the rupture front will lead to strengthening that further reduces the velocity, and under certain circumstances, healing of slip can occur. The boundary element method of Hamano (1974) is used in a program adapted from Andrews (1985) for numerical simulations of mode II rupture with two different velocity-dependent strength functions. For the first function, after a slip-weakening displacement, the crack follows an exponential velocity-weakening relation. The characteristic velocity V0 of the exponential determines the magnitude of the velocity-dependence at dynamic velocities. The velocity-dependence at high velocity is essentially zero when V0 is small and the resulting slip velocity distribution is similar to slip weakening. If V0 is larger, rupture propagation initially resembles slip-weakening, but spontaneous healing occurs behind the rupture front. The rise time and rupture propagation velocity depend on the choice of constitutive parameters. The second strength function is a natural log velocity-dependent form similar to constitutive laws that fit experimental rock friction data at lower velocities. Slip pulses also arise with this function. For a reasonable choice of constitutive parameters, slip pulses with this function do not propagate at speeds greater than the Raleighwave velocity. The calculated slip pulses are similar in many aspects to seismic observations of short rise time. In all cases of self-healing slip pulses, the residual stress increases with distance behind the trailing edge of the pulse so that the final stress drop is much less than the dynamic stress drop, in agreement with the model of Brune (1976) and some recent seismological observations of rupture.

Beeler, N.M.; Tullis, T.E.

1996-01-01

315

Patterns of Seismic and Aseismic Slip on Heterogeneous Faults  

NASA Astrophysics Data System (ADS)

Geological studies of exhumed faults and seismological observations reveal interesting aspects of fault heterogeneity. We thus carried numerical studies to explore the implications of fault heterogeneity on the organization of seismicity and transient aseismic slip. Our quasi-dynamic, continuum models are based on laboratory derived rate-and-state friction with heterogeneity introduced by spatial distributions of characteristic slip distance (Dc). We considered two types of faults, a simple strike-slip fault and a typical subduction fault; and two types of spatial distribution of Dc, a model with uniformly random log Dc distribution, and a hierarchical model of asperities with self-similar power-law asperity size distribution and Dc value proportional to asperity size. Our systematic study shows that by varying the distribution of Dc value, we are able to reproduce a wide variety of macroscopic fault behaviors ranging from characteristic seismic events to steady-slip. For different combinations of minimum and maximum Dc values on a fault we simulated multiple earthquake cycles with a total duration long enough to characterize the general behavior of the fault: characteristic (regularly repeating events that break the whole fault), non-characteristic (events with a range of magnitudes, in some cases with a complex but repeating pattern), aseismic transients and steady slip. We found that non-characteristic seismicity behavior occurs only over a relatively narrow range of Dc distributions. We extended our study in this regime and observed complex sequences of seismic events ranging over two orders of magnitude of seismic moments. We generated a synthetic catalog containing over 10,000 events and studied their source scaling relations. The catalog shows a transition in the moment magnitude (M0) - rupture area (A) scaling, from M0~A3/2 at low magnitudes to M0~A at large magnitudes, controlled by the effect of the finite seismogenic depth. Our modeling provides promising insight on the connections between the microscopic properties of the heterogeneous fault and the macroscopic behavior of the fault. The transition from seismic to aseismic events and steady-slip in these models may shed light on the transient behaviors of faults.

Luo, Y.; Ampuero, J. P.

2013-12-01

316

The Slumgullion Natural Laboratory for Observing Slip Phenomena  

NASA Astrophysics Data System (ADS)

Many natural systems release stresses by failure and sliding across surfaces; examples include landslides, glaciers, crustal- and plate-scale faults. Observational advances continue to reveal diversity in the seismic signals associated with fault slip and how such stress relaxation can occur, even on a single fault system. A particularly rich example are the episodes of slow fault slip near major subduction and transform plate boundaries that manifest as geodetically observed aseismic deformation abetted by a family of seismic signals depleted in high-frequencies relative to those from earthquakes (named ‘episodic tremor and slip’ or ETS). While the driving forces and scales differ, there are striking parallels between some observations and models of ETS and of landslide behaviors; e.g. in both, postulated key controls include rate-dependent friction and strength modulated by pore-pressure changes, dilatancy during rapid shear, and subsequent consolidation. To explore common features and the underlying processes we are studying the Slumgullion landslide, an ideal natural laboratory for observing fault slip and associated seismic and aseismic phenomena. Unlike crustal- or plate-scale studies significant deformation can be measured within a single field season, because the Slumgullion moves at average rates of cm/day. Moreover, pore pressures, displacements, material properties, and environmental variables may be measured directly and continuously at several locations on the landslide (albeit not at the basal sliding surface). We have just completed a field experiment on the Slumgullion to test several hypotheses, particularly that slip along the basal surface and side-bounding faults occurs with comparable richness of aseismic and seismic modes as crustal- and plate-scale boundaries. To do so from August 18-26, 2009 we continuously monitored the displacement-field using a robotic electronic displacement meter and the seismic radiation with 88 vertical-component seismographs [see Bodin et al., companion abstract]. Although we have only begun examining the data thus far, the seismic data contain an abundance of network-wide coherent signals with an amazing variety of characteristics. Significant unsteady movement in the displacement field is evident in the geodetic data, as well as fluctuations in the pore-pressures and relevant environmental parameters. Schulz et al. (companion abstract) presents initial landslide observations. We will form and present implications for understanding the likely mechanisms of failure and slip within natural systems.

Gomberg, J. S.; Schulz, W. H.; Bodin, P.; Kean, J. W.; Wang, G.; Coe, J. A.; MacQueen, P.; Foster, K.; Creager, K.

2009-12-01

317

Dual megathrust slip behaviors of the 2014 Iquique earthquake sequence  

NASA Astrophysics Data System (ADS)

The transition between seismic rupture and aseismic creep is of central interest to better understand the mechanics of subduction processes. A Mw 8.2 earthquake occurred on April 1st, 2014 in the Iquique seismic gap of northern Chile. This event was preceded by a long foreshock sequence including a 2-week-long migration of seismicity initiated by a Mw 6.7 earthquake. Repeating earthquakes were found among the foreshock sequence that migrated towards the mainshock hypocenter, suggesting a large-scale slow-slip event on the megathrust preceding the mainshock. The variations of the recurrence times of the repeating earthquakes highlight the diverse seismic and aseismic slip behaviors on different megathrust segments. The repeaters that were active only before the mainshock recurred more often and were distributed in areas of substantial coseismic slip, while repeaters that occurred both before and after the mainshock were in the area complementary to the mainshock rupture. The spatiotemporal distribution of the repeating earthquakes illustrates the essential role of propagating aseismic slip leading up to the mainshock and illuminates the distribution of postseismic afterslip. Various finite fault models indicate that the largest coseismic slip generally occurred down-dip from the foreshock activity and the mainshock hypocenter. Source imaging by teleseismic back-projection indicates an initial down-dip propagation stage followed by a rupture-expansion stage. In the first stage, the finite fault models show an emergent onset of moment rate at low frequency (< 0.1 Hz), while back-projection shows a steady increase of high frequency power (> 0.5 Hz). This indicates frequency-dependent manifestations of seismic radiation in the low-stress foreshock region. In the second stage, the rupture expands in rich bursts along the rim of a semi-elliptical region with episodes of re-ruptures, suggesting delayed failure of asperities. The high-frequency rupture remains within an area of local high trench-parallel gravity anomaly (TPGA), suggesting the presence of subducting seamounts that promote high-frequency generation. Our results highlight the complexity of the interactions between large-scale aseismic slow-slip and dynamic ruptures of megathrust earthquakes.

Meng, Lingsen; Huang, Hui; Bürgmann, Roland; Ampuero, Jean Paul; Strader, Anne

2015-02-01

318

Resolving slip evolution of deep tremor in western Japan  

NASA Astrophysics Data System (ADS)

Recent studies have shown that deep tectonic tremors in many subduction zones consist of numerous low-frequency earthquakes (LFEs) that occur as shear slips on the plate interface. LFE hypocenters are determined relatively accurately, and in western Japan, they are concentrated in a narrow zone around the anticipated plate interface [Ohta and Ide, 2011]. Therefore, the location of LFEs may constrain the instantaneous location of tremor sources and illustrate its migration behavior, as demonstrated by a matched filter analysis with template LFEs [Shelly et al., 2007]. Nevertheless, it is yet unclear whether tremor occurs at exactly the same location as LFEs. Since tremor behavior on the plate interface are various and spatially characteristic [Ide, 2010], there might be some tremor activity undetectable using template LFEs. Moreover, while the previous method using matched templates has achieved to draw the discrete picture of the slip behavior of potential tremor, it is not sufficient to explain the entire rupture process. To understand the underlying physics of tremor and other slow earthquakes, it is essential to highly resolve the spatial and temporal behavior of the rupture of these events. This study determines spatiotemporal slip distribution associated with deep tremor in western Japan, without the spatial limitation of template LFEs. We first estimate the location of the plate interface based on the precise hypocenter locations of LFEs in a target region and prepare "synthetic template waveforms" by stacking the seismograms of these LFEs at every grid point arranged on this interface. These synthetic template waveforms can be used in a matched filter analysis to continuous waveforms, to grasp a crude image of tremor source. Furthermore, we use the synthetic waveforms as substitute of Green's functions, and invert continuous tremor waveforms by a non-linear slip inversion method. We apply the method to 3600 s continuous velocity seismograms recorded at Hi-net stations in the western Shikoku, on 16 March, 2008 from 23:00-24:00, to obtain the detailed slip history of about 1200 s tremor sequence. The slip episode migrates from south to north and consists of three stages: (1) the southern part for 80 s, (2) the central part for several hundred seconds, and (3) the northern part for 60 s. Average migration velocity is between 10-50 m/s, and the first and third stages correspond to unknown VLF events. For all stages the cumulative moment functions increase basically along a common growth line, M_0(t)=6.0×10^10t, but in the two short stages, t^2-proportionalities are also observed in the short time ranges. These differences may be associated with the heterogeneities of material properties on the plate interface.

Ohta, K.; Ide, S.

2011-12-01

319

High pressure ceramic joint  

DOEpatents

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 4 figures.

Ward, M.E.; Harkins, B.D.

1993-11-30

320

High pressure ceramic joint  

DOEpatents

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Ward, Michael E. (Poway, CA); Harkins, Bruce D. (San Diego, CA)

1993-01-01

321

Cytoplasmic streaming in plant cells: the role of wall slip  

PubMed Central

We present a computer simulation study, via lattice Boltzmann simulations, of a microscopic model for cytoplasmic streaming in algal cells such as those of Chara corallina. We modelled myosin motors tracking along actin lanes as spheres undergoing directed motion along fixed lines. The sphere dimension takes into account the fact that motors drag vesicles or other organelles, and, unlike previous work, we model the boundary close to which the motors move as walls with a finite slip layer. By using realistic parameter values for actin lane and myosin density, as well as for endoplasmic and vacuole viscosity and the slip layer close to the wall, we find that this simplified view, which does not rely on any coupling between motors, cytoplasm and vacuole other than that provided by viscous Stokes flow, is enough to account for the observed magnitude of streaming velocities in intracellular fluid in living plant cells. PMID:22337633

Wolff, K.; Marenduzzo, D.; Cates, M. E.

2012-01-01

322

Magmatically triggered slow slip at Kilauea Volcano, Hawaii.  

PubMed

We demonstrate that a recent dike intrusion probably triggered a slow fault-slip event (SSE) on Kilauea volcano's mobile south flank. Our analysis combined models of Advanced Land Observing Satellite interferometric dike-intrusion displacement maps with continuous Global Positioning System (GPS) displacement vectors to show that deformation nearly identical to four previous SSEs at Kilauea occurred at far-field sites shortly after the intrusion. We model stress changes because of both secular deformation and the intrusion and find that both would increase the Coulomb failure stress on possible SSE slip surfaces by roughly the same amount. These results, in concert with the observation that none of the previous SSEs at Kilauea was directly preceded by intrusions but rather occurred during times of normal background deformation, suggest that both extrinsic (intrusion-triggering) and intrinsic (secular fault creep) fault processes can lead to SSEs. PMID:18755967

Brooks, Benjamin A; Foster, James; Sandwell, David; Wolfe, Cecily J; Okubo, Paul; Poland, Michael; Myer, David

2008-08-29

323

Competition between shear banding and wall slip in wormlike micelles  

E-print Network

The interplay between shear band (SB) formation and boundary conditions (BC) is investigated in wormlike micellar systems (CPyCl--NaSal) using ultrasonic velocimetry coupled to standard rheology in Couette geometry. Time-resolved velocity profiles are recorded during transient strain-controlled experiments in smooth and sand-blasted geometries. For stick BC standard SB is observed, although depending on the degree of micellar entanglement temporal fluctuations are reported in the highly sheared band. For slip BC wall slip occurs only for shear rates larger than the start of the stress plateau. At low entanglement, SB formation is shifted by a constant $\\Delta\\dot{\\gamma}$, while for more entangled systems SB constantly "nucleate and melt." Micellar orientation gradients at the walls may account for these original features.

Paul Lettinga; Sébastien Manneville

2009-11-24

324

Stress fluctuations and macroscopic stick-slip in granular materials.  

PubMed

This paper deals with the quasi-static regime of deformation of granular matter. It investigates the size of the Representative Elementary Volume (REV), which is the minimum packing size above which the macroscopic mechanical behaviour of granular materials can be defined from averaging. The first part uses typical results from recent literature and finds that the minimum REV contains in general 10 grains; this result holds true either for most experiments or for Discrete Element Method (DEM) simulation. This appears to be quite small. However, the second part gives a counterexample, which has been found when investigating uniaxial compression of glass spheres which exhibit stick-slip; we show in this case that the minimum REV becomes 10(7) grains. This makes the system not computable by DEM. Moreover, similarity between the Richter law of seism and the exponential statistics of stick-slip is stressed. PMID:15010916

Evesque, P; Adjémian, F

2002-11-01

325

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

326

Composite slip table of dissimilar materials for damping longitudinal modes  

DOEpatents

A vibration slip table for use in a vibration testing apparatus. The table s comprised of at least three composite layers of material; a first metal layer, a second damping layer, and a third layer having a high acoustic velocity relative to the first layer. The different acoustic velocities between the first and third layers cause relative shear displacements between the layers with the second layer damping the displacements between the first and third layers to reduce the table longitudinal vibration modes.

Gregory, Danny L. (Albuquerque, NM); Priddy, Tommy G. (Albuquerque, NM); Smallwood, David O. (Albuquerque, NM); Woodall, Tommy D. (Albuquerque, NM)

1991-01-01

327

Uninterrupted power supply using slip-power recovery induction generator  

Microsoft Academic Search

This paper describes an uninterrupted power supply (UPS) using a slip-power recovery induction generator with a battery-inverter system. This UPS has the following merits. The induction generator is started and accelerated quickly without load, since the UPS function is realized by a battery-inverter system. Once the generator is accelerated to a substantial speed, connection to the power system is performed

N. Kimura; K. Taniguchi

1995-01-01

328

Switching Transients in Static Slip-Energy Recovery Drive  

Microsoft Academic Search

This paper deals with the study of starting transients of a static slip-energy recovery drive. The non-linear equations of the system have been simulated on a digital computer and solved by the application of Runga-Kutta method. The effects of firing angle, load, system inertia and filter time constant on transient torques and speeds following a switching operation have been investigated.

V. N. Mittle; K. V. Katesan; S. C. Gupta

1979-01-01

329

Slip tapers at the tips of faults and earthquake ruptures  

Microsoft Academic Search

Slip gradients near the tips of earthquake ruptures and faults are typically linear. For non-interacting faults or earthquake ruptures, tip tapers are scale invariant, and about 1–2 orders of magnitude larger for faults than for earthquakes. For fault tips interacting with other faults, the taper can be as much as a factor of 10 greater than for non-interacting faults. For

Christopher H. Scholz; Theresa M. Lawler

2004-01-01

330

Controlling the deformation behavior of thermoplastic slips with ultrasound  

Microsoft Academic Search

The effect of ultrasound on the deformation properties of thermoplastic slips was investigated. It was shown that in treatment\\u000a with ultrasound, the change in the plastic strength of beryllium oxide — thermoplastic binder casting system in the process\\u000a temperature range (40–55°C) was due to cavitation and dissipative heat release effects and can be characterized with the equation\\u000a for a thermal

S. A. Shakhov

2007-01-01

331

Stick-Slip Dynamics Using Velcro as Model System  

NASA Astrophysics Data System (ADS)

Described by Galileo and further developed phenomenologically by Amontons and Coulomb, friction remains to be poorly understood especially with respect to its transition from the static to the kinetic regimes. In particular, the dynamics and control thereof of systems exhibiting stick-slip motion continues to be an area of fascination. The dry sliding behavior of the hook-and-loop system evinced by common Velcro captures many of the hallmarks of stick-slip motion typically manifested in systems at very small and very large length scales in addition to satisfying some of the classical laws as put forth by Amontons and Coulomb. Specifically, the kinetic frictional force is independent of driving velocity over nearly three orders of magnitude. In stark contrast to classical behavior, both the maximum static and the kinetic frictional forces reveal a linear dependence on the ``area of contact'' or more appropriately, hook number. Moreover, the frictional force (static and kinetic) exhibits a power law dependence on load with an exponent of approximately 0.25 similar to behavior seen in AFM, the implication being non-constant coefficients of static and kinetic friction. Statistical analysis shows that the fluctuations of stick-slip events follow a power law behavior with an exponent of approximately 0.5. Interestingly, this relatively simple system demonstrates evidence of precursor events prior to the onset of motion and may provide insight to the nucleation and transition from static to kinetic friction.

Mariani, Lisa; Esposito, Cara; Angiolillo, Paul

2013-03-01

332

Slipping Rib Syndrome in a Collegiate Swimmer: A Case Report  

PubMed Central

Objective: To present the unique case of a collegiate swimmer who experienced nearly 9 months of unresolved rib pain. Background: A 20-year-old collegiate swimmer was jumping up and down, warming up before a race, when she experienced pain in the area of her left lower rib cage. She completed the event and 2 additional events that day with moderate discomfort. The athlete was evaluated by a certified athletic trainer 3 days postinjury and followed up over the next 9 months with the team physician, a chiropractor, a nonsurgical sports medicine physician, and a thoracic surgeon. Differential Diagnosis: Intercostal strain, oblique strain, fractured rib, somatic dysfunction, hepatosplenic conditions, pleuritic chest pain, slipping rib syndrome. Treatment: The athlete underwent 4 months of conservative treatment (eg, activity modification, ice, ultrasound, hot packs, nonsteroidal anti-inflammatory drugs) after the injury, independently sought chiropractic intervention (12 treatments) 4 to 6 months postinjury, was referred to physical therapy (10 visits) by a nonsurgical sports medicine physician 6 to 8 months postinjury, and finally underwent surgical intervention 9 months after the onset of the initial symptoms. Uniqueness: Slipping rib syndrome was first described in 1919. However, many health care professionals who are involved with diagnosing and treating athletes and active individuals (eg, athletic trainers, physicians) are relatively unfamiliar with this musculoskeletal condition. Conclusions: It is important for clinicians and team physicians to familiarize themselves with and consider the diagnosis of slipping rib syndrome when assessing and managing individuals with persistent abdominal and/or thoracic pain. PMID:15970959

Udermann, Brian E; Cavanaugh, Daniel G; Gibson, Mark H; Doberstein, Scott T; Mayer, John M; Murray, Steven R

2005-01-01

333

Slow Slip Event at K?lauea Volcano  

NASA Astrophysics Data System (ADS)

Early in the morning of 1 February 2010 (UTC; early afternoon 31 January 2010 local time), continuous Global Positioning System (GPS) and tilt instruments detected a slow slip event (SSE) on the south flank of K?lauea volcano, Hawaii. The SSE lasted at least 36 hours and resulted in a maximum of about 3 centimeters of seaward displacement. About 10 hours after the start of the slip, a flurry of small earthquakes began (Figure 1) in an area of the south flank recognized as having been seismically active during past SSEs [Wolfe et al., 2007], suggesting that the February earthquakes were triggered by stress associated with slip [Segall et al., 2006]. SSE deformation was superimposed on long-term seaward motion of the south flank of about 7 centimeters per year, which occurs along a décollement or related low-angle faults shallower than 10 kilometers. Earthquakes triggered by an SSE in 2007 coincided spatially with typical décollement earthquakes [Syracuse et al., 2009], suggesting that the SSEs also occurred on the décollement.

Poland, Michael; Miklius, Asta; Wilson, David; Okubo, Paul; Montgomery-Brown, Emily; Segall, Paul; Brooks, Benjamin; Foster, James; Wolfe, Cecily; Syracuse, Ellen; Thurber, Clifford

2010-03-01

334

The assessment of the integration of slip resistance, thermal insulation and wearability of footwear on icy surfaces  

Microsoft Academic Search

Prevention of slip hazard in frozen environments is not paid much attention. Current winter and safety footwear does not provide sufficient slip resistance and appropriate wearability for use on icy surfaces. The objectives of this study were to assess the integration of slip resistance, thermal insulation, and wearability of footwear used on icy surfaces, and the anti-slip effect of materials

Chuansi Gao; John Abeysekera

2002-01-01

335

Dissimilar metals joint evaluation  

NASA Technical Reports Server (NTRS)

Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

Wakefield, M. E.; Apodaca, L. E.

1974-01-01

336

Excitation of energy harvesters using stick-slip motion  

NASA Astrophysics Data System (ADS)

During the past decades a large number of energy harvesting systems with the ability to transform mechanical energy into electrical energy have been proposed, ranging from systems exhibiting pure sinusoidal motion to stochastic systems. However, to date little emphasis has been put on stick-slip motion as a method for excitation of energy harvesting systems. Stick-slip motion can be associated with both microscopic and macroscopic processes and is omnipresent. The motion can be characterized by two stages. In the first stage there is buildup of elastic energy with little associated motion, whereas in the second stage the elastic energy is released into kinetic energy. We study here the spectral signal characteristics of two different electrical generators excited by stick-slip motion: a piezoelectric macro fiber composite and a triboelectric generator. The force and the voltage generated during the motion were monitored, and we found that the signal spectral density of both variables changes with the frequency in a characteristic manner, thus classifying the slip-stick motion as a colored noise excitation scheme. The force spectral density in both systems was found to exhibit a power-law spectrum following an {{f}^{-2}} trend, where f is the frequency. The voltage spectral density was governed by the product of a high-pass filter, the force spectral density, and the intrinsic generator spectral density. Here the piezoelectric generator exhibited a nearly flat voltage spectral density below the cutoff frequency of the high-pass filter and an {{f}^{-2}} spectrum at higher frequencies, thus demonstrating that the piezoelectric coupling coefficient had a nearly flat frequency response. On the other hand, the triboelectric generator had a coupling coefficient with a spectral response that varied in a non-systematic manner, possibly related to the large number of contact sites and relaxation times occurring during operation. The average power delivered by the generators to a resistive load was also measured for sinusoidal mechanical excitations and was compared with the average power generated by stick-slip motion.

Helseth, L. E.

2014-08-01

337

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

NASA Technical Reports Server (NTRS)

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 mold of the calcium sulfate-bonded investment material. The shell mold is cooled to room temperature, and a ceramic slip is poured therein. After a ceramic shell of desired thickness has set up in the shell mold, excess ceramic slip is poured out. While still wet, the shell mold is peeled from the ceramic shell to expose any delicate or detailed parts, after which the ceramic shell is cured to provide a complete, detailed, precision ceramic article without parting lines.

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

1993-01-01

338

Stick-slip motion of an Antarctic Ice Stream: The effects of viscoelasticity  

NASA Astrophysics Data System (ADS)

Stick-slip behavior is a distinguishing characteristic of the flow of Whillans Ice Stream (Siple Coast, Antarctica). Distinct from stick slip on Northern Hemisphere glaciers, which is generally attributed to supraglacial melt, the behavior is thought be controlled by basal processes and by tidally induced stress. However, the connection between stick-slip behavior and flow of the ice stream on long time scales, if any, is not clear. To address this question we develop a new ice flow model capable of reproducing stick-slip cycles similar to ones observed on the Whillans Ice Plain. The model treats ice as a viscoelastic material and emulates the weakening and healing that are suggested to take place at the ice-till interface. The model results suggest the long-term ice stream flow that controls ice discharge to surrounding oceans is somewhat insensitive to certain aspects of stick-slip behavior, such as velocity magnitude during the slip phase and factors that regulate it (e.g., elastic modulus). Furthermore, it is found that factors controlling purely viscous flow, such as temperature, influence stick-slip contribution to long-term flow in much the same way. Additionally, we show that viscous ice deformation, traditionally disregarded in analysis of stick-slip behavior, has a strong effect on the timing of slip events and therefore should not be ignored in efforts to deduce bed properties from stick-slip observations.

Goldberg, D. N.; Schoof, C.; Sergienko, O. V.

2014-07-01

339

Along-strike variations of the slip direction on normal faults: Insights from three-dimensional finite-element models  

Microsoft Academic Search

Normal faults in nature exhibit a systematic variation of the slip direction along strike, with pure dip-slip at their centres that changes gradually to oblique slip near their tips. Here we evaluate the variation of the slip direction along normal faults by three-dimensional finite-element modelling. The model results reveal a nearly linear increase of the strike-slip component over two-thirds of

Georgios Maniatis; Andrea Hampel

2008-01-01

340

New Joint Sealants. Criteria, Design and Materials.  

ERIC Educational Resources Information Center

Contents include--(1) sealing concrete joints, (2) sealing glass and metal joints, (3) metal and glass joint sealants from a fabricator's viewpoint, (4) a theory of adhesion for joint sealants, (5) geometry of simple joint seals under strain, (6) joint sealant specifications from a manufacturer's viewpoint, (7) joint sealant requirements from an…

Building Research Inst., Inc., Washington, DC.

341

Fault slip and earthquake recurrence along strike-slip faults - Contributions of high-resolution geomorphic data  

NASA Astrophysics Data System (ADS)

Understanding earthquake (EQ) recurrence relies on information about the timing and size of past EQ ruptures along a given fault. Knowledge of a fault's rupture history provides valuable information on its potential future behavior, enabling seismic hazard estimates and loss mitigation. Stratigraphic and geomorphic evidence of faulting is used to constrain the recurrence of surface rupturing EQs. Analysis of the latter data sets culminated during the mid-1980s in the formulation of now classical EQ recurrence models, now routinely used to assess seismic hazard. Within the last decade, Light Detection and Ranging (lidar) surveying technology and other high-resolution data sets became increasingly available to tectono-geomorphic studies, promising to contribute to better-informed models of EQ recurrence and slip-accumulation patterns. After reviewing motivation and background, we outline requirements to successfully reconstruct a fault's offset accumulation pattern from geomorphic evidence. We address sources of uncertainty affecting offset measurement and advocate approaches to minimize them. A number of recent studies focus on single-EQ slip distributions and along-fault slip accumulation patterns. We put them in context with paleoseismic studies along the respective faults by comparing coefficients of variation CV for EQ inter-event time and slip-per-event and find that a) single-event offsets vary over a wide range of length-scales and the sources for offset variability differ with length-scale, b) at fault-segment length-scales, single-event offsets are essentially constant, c) along-fault offset accumulation as resolved in the geomorphic record is dominated by essentially same-size, large offset increments, and d) there is generally no one-to-one correlation between the offset accumulation pattern constrained in the geomorphic record and EQ occurrence as identified in the stratigraphic record, revealing the higher resolution and preservation potential of the latter. While slip accumulation along a fault segment may be dominated by repetition of large, nearly constant offset increments, timing of surface-rupture is less regular.

Zielke, Olaf; Klinger, Yann; Arrowsmith, J. Ramon

2015-01-01

342

Joints in a Cornstarch Analog  

NSDL National Science Digital Library

Joints are very important to problems in applied geology (fluid flow, slope stability), but three-dimensional exposures of simple joint sets are not readily accessible from my campus. I developed this exercise based on the experiments of Miller (2001) to give students hands-on practice describing and interpreting joints. For the exercise, I prepare a cornstarch-water mixture a few days in advance and pour it into plastic petri dishes. I add a "flaw" to each dish (typically a small pebble). As the cornstarch dries, vertical joints develop. In class, each group of 3-4 students is provided a petri dish of desiccated cornstarch. Students are asked to draw a map of the joints, paying particular attention to intersection angles. (The joints curve to intersect at 90 degrees.) They determine relative ages of the joints using abutting relationships. (Typically 3-6 generations of joints.) Students next dissect the sample and describe the surface textures of the larger joints and the location of the flaw. The cornstarch produces beautiful plumose structure (hackles). Students then interpret the joint propagation direction from the surface textures, and note the origin of the joint. (Typically, a first- or second-generation joint initiates at the flaw.) Students discuss the role of flaws in the initiation of joints in their groups.

Crider, Juliet

343

Initiation time of near-infrared laser-induced slip on the surface of silicon wafers  

SciTech Connect

We have determined the initiation time of laser-induced slip on a silicon wafer surface subjected to a near-infrared continuous-wave laser by numerical simulations and experiments. First, numerical analysis was performed based on the heat transfer and thermoelasticity model to calculate the resolved shear stress and the temperature-dependent yield stress. Slip initiation time was predicted by finding the time at which the resolved shear stress reached the yield stress. Experimentally, the slip initiation time was measured by using a laser scattering technique that collects scattered light from the silicon wafer surface and detects strong scattering when the surface slip is initiated. The surface morphology of the silicon wafer surface after laser irradiation was also observed using an optical microscope to confirm the occurrence of slip. The measured slip initiation times agreed well with the numerical predictions.

Choi, Sungho [Graduate School of Mechanical Engineering, Hanyang University, Seoul 133–791 (Korea, Republic of); Jhang, Kyung-Young, E-mail: kyjhang@hanyang.ac.kr [School of Mechanical Engineering, Hanyang University, Seoul 133–791 (Korea, Republic of)

2014-06-23

344

Method of reducing the green density of a slip cast article  

DOEpatents

The method disclosed in this specification is one of reducing the green density of an article cast in a slip casting operation. The article is cast from a casting slip containing silicon metal particles, yttrium containing particles, and a small amount of a fluoride salt which is effective to suppress flocculation of the silicon metal particles by y.sup.+3 ions derived from the yttrium containing particles. The method is characterized by the following step. A small amount of compound which produces a cation which will partly flocculate the particles of silicon metal is added to the casting slip. The small amount of this compound is added so that when the casting slip is slip cast into a casting mold, the partly flocculated particles of silicon will interrupt an otherwise orderly packing of the particles of silicon and particles of yttrium. In this manner, the green density of the slip cast article is reduced and the article may be more easily nitrided.

Mangels, John A. (Flat Rock, MI); Dickie, Ray A. (Birmingham, MI)

1985-01-01

345

Imaging of the early acceleration phase of the 2013-2014 Boso slow slip event  

NASA Astrophysics Data System (ADS)

We analyze GPS and seismic data to examine the spatiotemporal evolution of a slow slip event (SSE) near Boso Peninsula, central Japan, from December 2013 to January 2014. The evolution of this SSE and its associated seismicity is divided into two distinct phases. Slip initially accelerated slowly with low slip rates, low propagation speeds, and no accompanying seismicity during the early phase and then accelerated more rapidly with higher slip rates, a higher propagation speed, and local earthquake swarm activity during the later phase. The seismicity was highly correlated in space and time with slip rate, suggesting that the swarm activity was triggered by stress loading due to the slow slip. The transition from the slow to faster phase shares some similarities with the nucleation of megathrust earthquakes inferred from foreshock activities, suggesting that SSEs may provide insights into the nucleation of large earthquakes.

Fukuda, Jun'ichi; Kato, Aitaro; Obara, Kazushige; Miura, Satoshi; Kato, Teruyuki

2014-11-01

346

Hip joint replacement  

MedlinePLUS

... Jones CA. Total joint arthroplasties: current concepts of patient outcomes after surgery. Rheum Dis Clin North Am . 2007;33(1):71-86. Schmalzried TP. Metal-metal bearing surfaces in hip arthroplasty. Orthopedics . 2009;32. Lindstrom D, Sadr Azodi O, Wladis ...

347

Dolphin Skeleton (Gliding Joint)  

NSDL National Science Digital Library

The dolphin is built to be sleek. Its body is made of almost entirely backbone (a gliding joint) which makes it very flexible under water. The ribs protect the inner organs of the dolphin and the tail beats from side to side, thrusting the animal forward.

Ketan Patel (California State University, Fullerton;)

2007-07-14

348

Clad metal joint closure  

SciTech Connect

A plasma arc spray overlay of cladding metals is used over joints between clad metal pieces to provide a continuous cladding metal surface. The technique permits applying an overlay of a high melting point cladding metal to a cladding metal surface without excessive heating of the backing metal.

Siebert, O.W.

1985-04-09

349

Experimental Modeling of Dynamic Shallow Dip-Slip Faulting  

NASA Astrophysics Data System (ADS)

In our earlier study (AGU 2005, SSJ 2005, JPGU 2006), using a finite difference technique, we have conducted some numerical simulations related to the source dynamics of shallow dip-slip earthquakes, and suggested the possibility of the existence of corner waves, i.e., shear waves that carry concentrated kinematic energy and generate extremely strong particle motions on the hanging wall of a nonvertical fault. In the numerical models, a dip-slip fault is located in a two-dimensional, monolithic linear elastic half space, and the fault plane dips either vertically or 45 degrees. We have investigated the seismic wave field radiated by crack-like rupture of this straight fault. If the fault rupture, initiated at depth, arrests just below or reaches the free surface, four Rayleigh-type pulses are generated: two propagating along the free surface into the opposite directions to the far field, the other two moving back along the ruptured fault surface (interface) downwards into depth. These downward interface pulses may largely control the stopping phase of the dynamic rupture, and in the case the fault plane is inclined, on the hanging wall the interface pulse and the outward-moving Rayleigh surface pulse interact with each other and the corner wave is induced. On the footwall, the ground motion is dominated simply by the weaker Rayleigh pulse propagating along the free surface because of much smaller interaction between this Rayleigh and the interface pulse. The generation of the downward interface pulses and corner wave may play a crucial role in understanding the effects of the geometrical asymmetry on the strong motion induced by shallow dip-slip faulting, but it has not been well recognized so far, partly because those waves are not expected for a fault that is located and ruptures only at depth. However, the seismological recordings of the 1999 Chi-Chi, Taiwan, the 2004 Niigata-ken Chuetsu, Japan, earthquakes as well as a more recent one in Iwate-Miyagi Inland, Japan in 2008, for example, seem to support the need for careful mechanical consideration. In this contribution, utilizing two-dimensional dynamic photoelasticity in conjunction with high speed digital cinematography, we try to perform "fully controlled" laboratory experiments of dip-slip faulting and observe the propagation of interface pulses and corner waves mentioned above. A birefringent material containing a (model) dip-slip fault plane is prepared, and rupture is initiated in that material using an Nd:YAG laser system, and the evolution of time-dependent isochromatic fringe patterns (contours of maximum in-plane shear stress) associated with the dynamic process of shallow dip-slip faulting is recorded. Use of Nd:YAG laser pulses, instead of ignition of explosives, for rupture initiation may enhance the safety of laboratory fracture experiments and enable us to evaluate the energy entering the material (and hence the energy balance in the system) more precisely, possibly in a more controlled way.

Uenishi, K.

2010-12-01

350

Comparison of Three Different Slip Meters under Various Contaminated Conditions  

PubMed Central

Objectives To challenge the problem of slipperiness, various slipmeters have been developed to assess slip hazard. The performance of in-situ slipmeter is, however, still unclear under the various floor conditions. The main objectives of this study were to evaluate the performance of three kinds of slipmeters under real conditions, and to find their dynamic and kinematic characteristics, which were compared with gait test results. Methods Four common restaurant floor materials were tested under five contaminants. Slipmeters and human gaits were measured by high speed camera and force plate to find and compare their dynamic and kinematic characteristics. Results The contact pressures and built-up ratio were below those of subjects. The sliding velocity of British Pendulum Tester was above those of subjects, while those of BOT-3000 and English XL were below those of subjects. From the three meters, the English XL showed the highest overall correlation coefficient (r = 0.964) between slip index and Ra, while the rest did not show statistical significance with surface roughness parameters (Ra, Rz). The English XL only showed statistical significance (p < 0.01) between slip index and contaminants. The static coefficient of friction obtained with the BOT-3000 showed good consistency and repeatability (CV < 0.1) as compared to the results for the BPT (CV > 0.2) and English XL (CV < 0.2). Conclusion It is unclear whether surface roughness can be a reliable and objective indicator of the friction coefficient under real floor conditions, and the viscosity of contaminants can affect the friction coefficient of the same floors. Therefore, to evaluate slipperiness, the performance of the slipmeters needed to improve. PMID:22953227

2012-01-01

351

Slipping Rib Syndrome in a Collegiate Swimmer: A Case Report.  

PubMed

Objective: To present the unique case of a collegiate swimmer who experienced nearly 9 months of unresolved rib pain.Background: A 20-year-old collegiate swimmer was jumping up and down, warming up before a race, when she experienced pain in the area of her left lower rib cage. She completed the event and 2 additional events that day with moderate discomfort. The athlete was evaluated by a certified athletic trainer 3 days postinjury and followed up over the next 9 months with the team physician, a chiropractor, a nonsurgical sports medicine physician, and a thoracic surgeon.Differential Diagnosis: Intercostal strain, oblique strain, fractured rib, somatic dysfunction, hepatosplenic conditions, pleuritic chest pain, slipping rib syndrome.Treatment: The athlete underwent 4 months of conservative treatment (eg, activity modification, ice, ultrasound, hot packs, nonsteroidal anti-inflammatory drugs) after the injury, independently sought chiropractic intervention (12 treatments) 4 to 6 months postinjury, was referred to physical therapy (10 visits) by a nonsurgical sports medicine physician 6 to 8 months postinjury, and finally underwent surgical intervention 9 months after the onset of the initial symptoms.Uniqueness: Slipping rib syndrome was first described in 1919. However, many health care professionals who are involved with diagnosing and treating athletes and active individuals (eg, athletic trainers, physicians) are relatively unfamiliar with this musculoskeletal condition.Conclusions: It is important for clinicians and team physicians to familiarize themselves with and consider the diagnosis of slipping rib syndrome when assessing and managing individuals with persistent abdominal and/or thoracic pain. PMID:15970959

Udermann, Brian E; Cavanaugh, Daniel G; Gibson, Mark H; Doberstein, Scott T; Mayer, John M; Murray, Steven R

2005-06-01

352

Strike-slip fault evolution on Europa: evidence from tailcrack geometries  

Microsoft Academic Search

Secondary cracks are commonly produced at stress concentration points at the tips of slipping interfaces such as faults. These so-called tailcracks form an antisymmetric pattern at opposite tips of the fault with a fracture geometry that is a mechanical indicator of the sense of slip, whether left-lateral or right-lateral. I present descriptions of tailcracks along numerous strike-slip faults on Europa.

Simon A. Kattenhorn

2004-01-01

353

On first cycle slip time of phase-locked loops in cascade  

NASA Technical Reports Server (NTRS)

Precise measurement and spacecraft tracking are obtained by using phase-locked loops in cascade in two-way communications links. Statistics on cycle slip time are of vital importance in system planning and design. This paper presents: (1) results of a computer simulation study of the mean time to first cycle slip of cascade phase-locked loops preceded by bandpass limiters, and (2) the determination of probability distributions of cycle slip. Numerical results are obtained for a typical coherent communication system.

Yuen, J. H.

1974-01-01

354

Constraining the relation between tremor and slow slip using tremor distributions and PBO strainmeter data  

NASA Astrophysics Data System (ADS)

The relationship between tremor and slow slip can be viewed in the context of a rate-and-state formulation. The expected distribution of slip rate inside a slow slip pulse exhibits a large slip rate in the leading front that decays back towards the healing front. We stacked along-strike tremor distributions on the advancing tremor fronts for 6 major Cascadia ETS events, and observed a skewed spatial distribution of tremor rate, consistent with that expected in a slow slip pulse. Our analysis places further physical constraints on the duration, width, and along-strike extent of a slow slip pulse. Source scaling laws predict the width of propagation patterns, given the observed propagation velocities (pers. comm. J-P Ampuero). The recently-observed tremor migration pattern termed Rapid Tremor Reversal (RTR) is ˜15 km wide, consistent with the theoretically-predicted width. We examine signatures of tremor migration in the accumulating data from PBO borehole strainmeters in Cascadia. First, some RTRs appear to be recorded by strainmeters, and analysis of those signals may provide constraints on the geometry and amount of slip in RTRs. In addition, we aim to interrogate strain data to place constraints on the updip extent of slip in large Northern Washington ETS events, in order to resolve the down-dip discrepancy between tremor locations and that of slip from inversion of GPS data (Wech et al., JGR, 2009). We use the location, timing, and density of observed tremor to help constrain the assumed slipping surface, as well as our theoretically and empirically derived constraints on a slow slip pulse. Thus, a relatively realistic slip geometry is used to predict the strain changes expected from recent large ETS events.

Delbridge, B.; Houston, H.

2010-12-01

355

Mechanical constraints on inversion of co-seismic geodetic data for fault slip and geometry  

Microsoft Academic Search

Modern geodetic techniques, such as the Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), provide high-precision deformation measurements of earthquakes. Through elastic models and mathematical optimization methods, the observations can be related to a slip-distribution model. The classic linear, kinematic, and static slip inversion problem requires specification of a smoothing norm of slip parameters and a residual norm

F. Liang; J. Sun; K. M. Johnson; Z. Shen; R. Burgmann

2010-01-01

356

Slip distribution of the 2003 Tokachi-oki earthquake estimated from tsunami waveform inversion  

Microsoft Academic Search

The slip distribution of the 2003 Tokachi-oki earthquake is estimated from the 11 tsunami waveforms recorded at 9 tide gauges in the southern Hokkaido and eastern Tohoku coasts and two ocean bottom tsunami-meters (pressure gauges) off Kamaishi, Tohoku. The largest slip of 4.3 m is estimated on the subfault located off Hiroo. A large slip of 2.1 m is also

Yuichiro Tanioka; Kenji Hirata; Ryota Hino; Toshihiko Kanazawa

2004-01-01

357

A photoelastic study of slip on an artificial fault in a multilayered medium  

E-print Network

to understand the processes associated with the generation of earthquakes, a knowledge of the physical parameters governing the resistance to slip along pr e- existing faults is required. The significance and location of these phenomena must be determined so... to an understanding of earthquake sources. During an earthquake, slip along the fault surface is not uniform. Certain areas along the surface are pinned, locking the fault while other sections slip freely. In order to predict or modify an earthquake the location...

Coyne, John Christopher

1979-01-01

358

Stick-slip transition in capillary flow of linear polyethylene: 3. Surface conditions  

Microsoft Academic Search

Effects of surface topology and energy on the stick-slip transition were studied in capillary flow of highly entangled polyethylene (PE) melts. Surface roughness was shown to increase the critical stress of the stick-slip transition because of the increased resistance to interfacial disentanglement. Lowering the surface energy of a smooth die wall by treatment with a fluorocarbon completely eliminates the stick-slip

Shi-Qing Wang; Patrick A. Drda

1997-01-01

359

On the application of no-slip lateral boundary conditions to ‘coarsely’ resolved ocean models  

Microsoft Academic Search

The problem of no-slip boundary conditions as they apply to ocean models is revisited. It is argued that the setting is consistent with classical Law of the Wall theory. The rendering of no-slip boundary conditions is thus modified importantly from typical practice in ocean models. The proposed boundary condition formulation is implemented in the MITgcm. Comparisons with classically formulated free-slip

Bruno Deremble; Andrew Mc C. Hogg; Pavel Berloff; W. K. Dewar

2011-01-01

360

Strike-slip faulting of ridged plains near Valles Marineris, Mars  

NASA Astrophysics Data System (ADS)

This paper identifies and documents several well-preserved examples of Martian strike-slip faults and examines their relationships to wrinkle-ridges. The strike-slip faulting predates or overlaps periods of wrinkle-ridge growth southeast of Valles Marineris, and some wrinkle ridges may have nucleated and grown as a result of strike-slip displacements along the echelon fault arrays. Lateral displacements of several km inferred along these arrays may be related to tectonism in Tharsis.

Schultz, R. A.

1989-10-01

361

Joint Institute Marine and Atmospheric  

E-print Network

Joint Institute for Marine and Atmospheric Research NATIONALOCEA NIC AND ATMOSPHERIC ADMINISTRATION Contribution 00-328 #12;ii This research is funded by Cooperative Agreement Number NA67RJ0154 between the Joint

Hawai'i at Manoa, University of

362

Composite slip table of dissimilar materials for damping longitudinal modes  

DOEpatents

A vibration slip table for use in a vibration testing apparatus is disclosed. The tables comprised of at least three composite layers of material; a first metal layer, a second damping layer, and a third layer having a high acoustic velocity relative to the first layer. The different acoustic velocities between the first and third layers cause relative shear displacements between the layers with the second layer damping the displacements between the first and third layers to reduce the table longitudinal vibration modes. 6 figures.

Gregory, D.L.; Priddy, T.G.; Smallwood, D.O.; Woodall, T.D.

1991-06-18

363

Constant slip control of induction motor at light load  

SciTech Connect

The most widely used AC motor drives adopt Rated Flux Control (RFC) method. However, at light load condition, RFC causes excessive iron loss, thus the conversion efficiency of the drive system impaired. This paper introduces a new control approach--Constant Slip Control (CSC), which minimize the stator current at light load, so that the iron loss and reactive power consumption of the motor are decreased. Simulation results compare the power consumption of CSC with that of RFC in order to validate the theoretical development. In the last part, realization of CSC is discussed.

Feng Xiaogang; Chen Boshi [Shanghai Univ. (China). School of Automation

1996-12-31

364

Wear and Cohesion During Frictional Slip Along Carbonate Faults  

NASA Astrophysics Data System (ADS)

Our recent experiments with rotary shear of solid rock blocks showed that smoothening of carbonate faults during high-velocity slip leads to significant reduction of both friction and wear-rate. Chen et al. (2013) characterized roughness and friction down to sub-micron scale, and found that smoothing leads to friction reduction. They showed that friction coefficient correlates with surface roughness below 100 nm RMS roughness whereas no weakening occurred with higher roughness. Boneh et al. (2013) sheared limestone and dolomite fault at normal stress up to 7 MPa and slip-velocity up to 1 m/s during steady-state. At low velocities (V < 0.3 m/s), the wear-rate depends on the normal stress, as expected, but at higher velocities the wear-rates are low to vanishing with no dependence on the normal stress. Faults run at high-velocity displayed smooth, hard surfaces. These results allow quantifying the relations between wear, cohesion and friction. Frictional strength is the integrated effect of adhesion (= cohesion), fracturing (= wear), and plastic deformation along a slipping fault. The above results indicate that during the steady-state slip along the smooth, hard, wear-resistant surfaces of the experimental faults occurred with negligible fracturing and plastic deformation. Thus, adhesion became the dominant contributor to the frictional resistance. To test this hypothesis, the experimental cohesion, C, is compared with independently measured calcite adhesion. We use the Mohr diagram to calculate the cohesion of 22 experiments with Dover limestone, ran at velocities 0.005-0.31 m/s and normal stress up to 3 MPa, and 66 experiments with Kasota dolomite, ran at velocities 0.01-0.97 m/s and normal stress up to 7 MPa,. These calculations yielded C = 0.054 +/- 0.055 MPa for the limestone, and C = 0.463 +/- 0.190 MPa for the dolomite. Adhesion can be measured directly with Atomic-Force-Microscope (AFM) by using tiny cantilever with tips with tens of nm radius of curvature. We used several approaches to calculate calcite adhesion from the AFM measurements of Cubillas & Higgins (Geochemical transactions, 2009) and Lomboy et al. (Cement & Concrete Res., 2011) that were conducted on smooth surfaces of cleaved calcite either in air or in solution. We obtained a wide range for values from 0.2 MPa to 4.8 MPa, that are generally equal or higher than the cohesion in the limestone and dolomite experiments. The implications of these results to frictional faulting will be discussed.

Reches, Z.; Chen, X.; Boneh, Y.; Madden, A. S.

2013-12-01

365

Slip effects associated with Knudsen transport phenomena in porous media  

NASA Technical Reports Server (NTRS)

Porous media used in phase separators and thermomechanical pumps have been the subject of characterization efforts based on the Darcy permeability of laminar continuum flow. The latter is not always observed at low speed, in particular at permeabilities below 10 to the -9th/squared cm. The present experimental and theoretical studies address questions of slip effects associated with long mean free paths of gas flow at room temperature. Data obtained are in good agreement, within data uncertainty, with a simplified asymptotic Knudsen equation proposed for porous plugs on the basis of Knudsen's classical flow equation for long mean free paths.

Frederking, T. H. K.; Hepler, W. A.; Khandhar, P. K.

1988-01-01

366

Dynamic slip velocity correlation using non-spherical particles  

E-print Network

RECOMMENDATIONS NOMENCLATURE REFERENCES APPENDIX A . 1 2 6 11 13 15 15 25 31 31 36 42 43 45 47 APPENDIX B . Page 57 113 LIST OF FIGURES FIGURE 1: DRAG COEFFICIENT VS. PARTICLE REYNOLDS NUMBER FOR VARIOUS SHAPED PARTICLES FIGURE 2...: C VS. N?~ FOR DIFFERENT SPHERICITIES USING THE EXPERIMENTAL CORRELATION FIGURE 15 Q VS N~p THE FINAL CORRELATION FOR USE IN ESTIMATING SLIP VELOCITY FIGURE 16: FLUID RHEOLOGY CURVE FOR 1. 0 LB/BBL. HEC IN CARTESIAN COORDINATES FIGURE 17: FLUID...

Pecore, Douglas Wilkin

2012-06-07

367

Slip and Dilation Tendency Analysis of the Patua Geothermal Area  

DOE Data Explorer

Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Slip and dilation tendency analysis for the Patua geothermal system was calculated based on faults mapped in the Hazen Quadrangle (Faulds et al., 2011). Patua lies near the margin between the Basin and Range province, which is characterized by west-northwest directed extension and the Walker Lane province, characterized by west-northwest directed dextral shear. As such, the Patua area likely has been affected by tectonic stress associated with either or both of stress regimes over geologic time. In order to characterize this stress variation we calculated slip tendency at Patua for both normal faulting and strike slip faulting stress regimes. Based on examination of regional and local stress data (as explained above) we applied at shmin direction of 105 to Patua. Whether the vertical stress (sv) magnitude is larger than ...

Faulds, James E.

368

Northern Cascadia Episodic Tremor and Slip: Cycles Within Cycles  

NASA Astrophysics Data System (ADS)

Episodic tremor and slip (ETS) events, each with geodetically determined moment magnitudes in the mid-6 range, repeat with remarkable regularity every 15 months under the Olympic Peninsula/southern Vancouver Island region. We have automatically searched for non-volcanic tremor in all 5-minute time windows both during the past 4 ETS events and during the inter-ETS period from February, 2007 through April, 2008. Inter- ETS tremor was detected in nearly 3000 windows, which overlap by 50%, so tremor was seen 2% of the time. The catalog of 5-minute tremor locations cluster in time and space into groups we call tremor swarms, revealing 35 inter-ETS tremor swarms. The number of hours of tremor per swarm ranged from about one to 50 hours, totaling 193 hours. The inter-ETS tremor swarms generally locate along the downdip side of the major ETS events, and account for approximately 45% of the time that tremor has been detected during the last entire ETS cycle, which includes the May, 2008 ETS episode. Many of the inter-ETS events are near-carbon copies in duration, spatial extent and propagation direction, as is seen for the larger 15-month-interval events. These 35 inter-ETS swarms plus one major ETS episode follow a power law relationship such that the number of swarms, N, exceeding duration ? is given by N ~ ?-0.6. If we assume that seismic moment is proportional to ? as proposed by Ide et al. [Nature, 2007], we find that the tremor swarms follow a standard Gutenberg-Richter logarithmic frequency-magnitude relation, log10N ~ 10-bMw, with b = - 0.9, which lies in the range for normal earthquake catalogs. Furthermore, the major ETS events fall on the curve defined by the inter-ETS swarms, suggesting that the inter-ETS swarms are just smaller versions of the major 15-month ETS events. Only the largest events coincide with geodetically observed slip, suggesting that current geodetic observations may be missing nearly half of the total slip. Finally, crude estimates of the spatial dimensions of tremor swarms L suggest that L ~ ?1/n where n is between 2 and 3. A value of 2 is consistent with slip propagation rates being controlled by a diffusional process. In contrast, n is observed to be about 1 for normal earthquakes because rupture generally propagates at a velocity close to the shear-wave speed.

Creager, K. C.; Wech, A. G.; Vidale, J. E.

2009-05-01

369

Slow-Slip Scaling Laws Inferred from Cascadia Tremor Swarms  

NASA Astrophysics Data System (ADS)

Episodic tremor and slip (ETS) events, each with geodetically determined moment magnitudes in the mid-6 range, repeat about every 15 months under the Olympic Peninsula/southern Vancouver Island region. We have applied an automatic waveform envelope cross-correlation and clustering (WECC) algorithm to seven Cascadia-wide subarrays to search for non-volcanic tremor in 5-minute, 50% overlapping, time windows, revealing 70,000 tremor epicenters. The tremor epicenters cluster in time and space into nearly 200 tremor swarms. The number of hours of tremor per swarm ranges from about 1 to 470 hours. The smaller (inter-ETS) tremor swarms generally locate along the downdip side of the larger ETS swarms and occur much more frequently. In northern Washington, which is currently best monitored, the ETS events, as well as the larger inter-ETS tremor swarms initiate downdip and propagate updip. For the large ETS events, tremor swarm duration is proportional to geodetically determined seismic moment. We consider tremor swarms to be a proxy for slow slip for the smaller events as well, even though slip would be below current geodetic detection thresholds. An interpretation of the observed transition from longer duration, less frequent tremor swarms up dip to smaller more frequent tremor swarms down-dip, in terms of fault strength is the subject of a presentation by Wech. The combined inter-ETS and ETS swarms follow a power law relationship such that the number of swarms, N, exceeding duration ? is given by ? -0.66. If we assume that seismic moment is proportional to ?, as proposed by Ide et al. [Nature, 2007], we find that the tremor swarms follow a standard Gutenberg-Richter logarithmic frequency-magnitude relation, log10 N ? -bMw, with b = 1.0, which lies in the range for normal earthquake catalogs. Finally, crude estimates of the spatial dimensions of tremor swarms L suggest that L ? ? 1/n where n is between 2 and 3. A value of 2 is consistent with slip propagation rates being controlled by a diffusional process. In contrast, n is observed to be about 1 for normal earthquakes because rupture generally propagates at a velocity close to the shear-wave speed.

Creager, K. C.; Wech, A.; Vidale, J. E.

2010-12-01

370

Electrification : A New Approach To Evaluate Slip Velocity During Flow Instabilities  

NASA Astrophysics Data System (ADS)

The original feature of this work consists in the parallel study, in extrusion, of the polymer electrification and flow instabilities. On one hand, the Mhetar and Archer model has been used to predict the evolution of slip velocity versus shear stress and on the other hand, the double layer theory seem to be the better theory to explain electrification. We have shown that electrification measurements allow us to measure the slip velocity. The slip velocity values calculated via double layer theory are consistent with those calculated with the Methar and Archer model and allow us to validate our approach. The conclusion is that it's possible to determine the slip velocity during flow instabilities.

Flores, Fabrice; Allal, Ahmed; Guerret-Piècourt, Christelle

2007-04-01

371

Design study for a liquid metal slip ring solar array orientation mechanism  

NASA Technical Reports Server (NTRS)

The design of a single axis orientation mechanism for solar arrays on high power synchronous satellites is studied primarily with respect to providing 116 liquid metal slip rings for reduced friction and improved electrical characteristics. Designs and tradeoff studies for the slip rings and other components are presented. An assembly containing 33 slip rings of three design approaches was designed, fabricated, and vacuum tested to 30 amperes and 30,000 volts. Containment of the liquid metal gallium in large diameter slip rings was difficult. A design approach is presented which is expected to provide improved retention of the liquid metal.

Clark, R. B.

1972-01-01

372

Earthquake slip vectors and estimates of present-day plate motions  

NASA Technical Reports Server (NTRS)

Two alternative models for present-day global plate motions are derived from subsets of the NUVEL-1 data in order to investigate the degree to which earthquake slip vectors affect the NUVEL-1 model and to provide estimates of present-day plate velocities that are independent of earthquake slip vectors. The data set used to derive the first model excludes subduction zone slip vectors. The primary purpose of this model is to demonstrate that the 240 subduction zone slip vectors in the NUVEL-1 data set do not greatly affect the plate velocities predicted by NUVEL-1. A data set that excludes all of the 724 earthquake slip vectors used to derive NUVEL-1 is used to derive the second model. This model is suitable as a reference model for kinematic studies that require plate velocity estimates unaffected by earthquake slip vectors. The slip-dependent slip vector bias along transform faults is investigated using the second model, and evidence is sought for biases in slip directions along spreading centers.

Demets, Charles

1993-01-01

373

Modifiable performance domain risk-factors associated with slip-related falls.  

PubMed

Falls are a major source of injury in older adults. Many falls occur after slipping. This study determined performance-related factors that both contribute to slip-related falls and that may be effectively and efficiently modified through targeted intervention. Thirty-five young adults and 21 healthy older adults (age: 70.9+/-5.1 years) were slipped in a laboratory using a slippery surface. The biomechanics of the 18 older adults who fell and the 30 younger adults who recovered following slips were analyzed. A set of potentially modifiable variables, initially based on significant between-groups differences, was further analyzed using stepwise discriminant analysis and logistic regression. The discriminant analysis correctly categorized 93.8% of the falls and recoveries based on two variables; the velocity of the slipping foot relative to the velocity of the whole body center of mass (COM), and the lateral placement of the recovery foot relative to the COM. The logistic regression determined the expected change in the odds of a recovery following a slip given a hypothesized intervention-induced improvement of these variables. Decreased velocity of the slipping foot relative to the COM, or decreased lateral placement of the recovery foot relative to the COM to zero, increased the odds of recovery by 17% and 27%, respectively. This suggests that intervention targeted at improving these specific lower extremity control variables following the onset of a slip has the potential to significantly decrease slip-related fall risk. PMID:18396048

Troy, Karen L; Donovan, Stephanie J; Marone, Jane R; Bareither, Mary Lou; Grabiner, Mark D

2008-10-01

374

Influence of an anisotropic slip-length boundary condition on turbulent channel flow  

NASA Astrophysics Data System (ADS)

The effects of an anisotropic Navier slip-length boundary condition on turbulent channel flow are investigated parametrically by direct numerical simulations. The slip-length boundary condition is made direction dependent by specifying the value of the slip length independently for the streamwise and spanwise direction. The change in drag is mapped versus a wide range of streamwise and spanwise slip-length combinations at two different friction Reynolds numbers, Re_{tau _0}=180 and Re_{tau _0}=360. For moderate slip lengths both drag-reducing and drag-increasing slip-length combinations are found. The percentage drag increase saturates at approximately 60% for high spanwise slip. Once a threshold value for the streamwise slip length is exceeded, drag is reduced in all cases irrespective of the value of the spanwise slip length. The Reynolds number appears to have only little influence on the change in drag for the moderate Reynolds numbers studied here. A detailed comparison with the implicit theoretical formula of Fukagata et al. [Phys. Fluids 18, 051703 (2006)], which relates the change in drag with the streamwise and spanwise slip length, has been made. In general, this formula gives a fair representation of the change in drag; a modified version of this relation is presented, which improves the prediction for the change in drag for small slip length values and reduces the number of free parameters contained in the model. The effects of the slip-length boundary condition on the flow are further investigated using mean flow and turbulence statistics. For drag-neutral slip-length combinations the level of turbulent fluctuations is approximately unchanged. The presence of a slip-length boundary condition affects both the level of wall-shear stress fluctuations and the degree of intermittency of the wall-shear stress probability density function. The correlation statistics of the velocity field show that a high spanwise slip length causes a disruption of the near-wall streaks, while high streamwise slip favours an increasing streak regularity.

Busse, A.; Sandham, N. D.

2012-05-01

375

Strength of stick-slip and creeping subduction megathrusts from heat flow observations.  

PubMed

Subduction faults, called megathrusts, can generate large and hazardous earthquakes. The mode of slip and seismicity of a megathrust is controlled by the structural complexity of the fault zone. However, the relative strength of a megathrust based on the mode of slip is far from clear. The fault strength affects surface heat flow by frictional heating during slip. We model heat-flow data for a number of subduction zones to determine the fault strength. We find that smooth megathrusts that produce great earthquakes tend to be weaker and therefore dissipate less heat than geometrically rough megathrusts that slip mainly by creeping. PMID:25170149

Gao, Xiang; Wang, Kelin

2014-08-29

376

Mechanical Models of Coontinental Plate BoundariesL Fault Slip Rates and Interseismic Stress Rotation Rates.  

E-print Network

??We first describe the methodology for a two-dimensional, elastic deformable microplate modeling approach for continental plate boundaries. Deformable microplate models combine discrete slip on microplate… (more)

Langstaff, Meredith Avery

2014-01-01

377

Influence of fault connectivity on slip rates in southern California: Potential impact on discrepancies between geodetic derived and geologic slip rates  

NASA Astrophysics Data System (ADS)

the San Bernardino strand of the San Andreas fault (SAF) and across the eastern California shear zone (ECSZ), geologic slip rates differ from those inverted from geodetic measurements, which may partly be due to inaccurate fault connectivity within geodetic models. We employ three-dimensional models that are mechanically compatible with long-term plate motion to simulate both fault slip rates and interseismic surface deformation. We compare results from fault networks that follow mapped geologic traces and resemble those used in block model inversions, which connect the San Jacinto fault to the SAF near Cajon Pass and connect distinct faults within the ECSZ. The connection of the SAF with the San Jacinto fault decreases strike-slip rates along the SAF by up to 10% and increases strike-slip rates along the San Jacinto fault by up to 16%; however, slip rate changes are still within the large geologic ranges along the SAF. The insensitivity of interseismic surface velocities near Cajon Pass to fault connection suggests that inverse models may utilize both an incorrect fault geometry and slip rate and still provide an excellent fit to interseismic geodetic data. Similarly, connection of faults within the ECSZ produces 36% greater cumulative strike-slip rates but less than 17% increase in interseismic velocity. When using overconnected models to invert GPS for slip rates, the reduced off-fault deformation within the models can lead to overprediction of slip rates. While the nature of fault intersections at depth remains enigmatic, fault geometries should be chosen with caution in crustal deformation models.

Herbert, Justin W.; Cooke, Michele L.; Marshall, Scott T.

2014-03-01

378

Joint Seminar UNIVERSITY OF GEORGIA  

E-print Network

Joint Seminar UNIVERSITY OF GEORGIA DEPARTMENT OF STATISTICS DEPARTMENT OF EPIDEMIOLOGY longitudinal covariates are involved in the modeling of the survival data. A joint likelihood approach has been data. However, in the presence of left truncation, there are additional challenges for the joint

Wang, Lily

379

JOINT PERFORMANCE Guide for Optimum  

E-print Network

July 2012 JOINT PERFORMANCE Guide for Optimum of Concrete Pavements #12; #12;Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2. Report Date Guide for Optimum Joint Performance of Concrete Pavements July 2012 6. Performing

380

Double slotted socket spherical joint  

DOEpatents

A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2001-05-22

381

Joint Degrees & Promotion towards European Students  

E-print Network

Joint Degrees & Promotion towards European Students 26 June 2014 MATTEA CAPELLI & ALESSANDRA GALLERANO INTERNATIONAL OFFICE #12;Joint Degrees and Promotion towards European students Joint degrees guidelines and template for agreements Support to student participation Promotion of Joint Degrees towards

Di Pillo, Gianni

382

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2012-10-01

383

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2013-10-01

384

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2011-10-01

385

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2010 CFR

...Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2010-10-01

386

Secondary Fracturing of Europa's Crust in Response to Combined Slip and Dilation Along Strike-Slip Faults  

NASA Technical Reports Server (NTRS)

A commonly observed feature in faulted terrestrial rocks is the occurrence of secondary fractures alongside faults. Depending on exact morphology, such fractures have been termed tail cracks, wing cracks, kinks, or horsetail fractures, and typically form at the tip of a slipping fault or around small jogs or steps along a fault surface. The location and orientation of secondary fracturing with respect to the fault plane or the fault tip can be used to determine if fault motion is left-lateral or right-lateral.

Kattenhorn, S. A.

2003-01-01

387

Fault Wear by Damage Evolution During Steady-State Slip  

NASA Astrophysics Data System (ADS)

Slip along faults generates wear products such as gouge layers and cataclasite zones that range in thickness from sub-millimeter to tens of meters. The properties of these zones apparently control fault strength and slip stability. Here we present a new model of wear in a three-body configuration that utilizes the damage rheology approach and considers the process as a microfracturing or damage front propagating from the gouge zone into the solid rock. The derivations for steady-state conditions lead to a scaling relation for the damage front velocity considered as the wear-rate. The model predicts that the wear-rate is a function of the shear-stress and may vanish when the shear-stress drops below the microfracturing strength of the fault host rock. The simulated results successfully fit the measured friction and wear during shear experiments along faults made of carbonate and tonalite. The model is also valid for relatively large confining pressures, small damage-induced change of the bulk modulus and significant degradation of the shear modulus, which are assumed for seismogenic zones of earthquake faults. The presented formulation indicates that wear dynamics in brittle materials in general and in natural faults in particular can be understood by the concept of a "propagating damage front" and the evolution of a third-body layer.

Lyakhovsky, Vladimir; Sagy, Amir; Boneh, Yuval; Reches, Ze'ev

2014-11-01

388

Use of concentrated solar energy to form slip coatings  

NASA Astrophysics Data System (ADS)

Melted slip coatings were obtained and the structural changes in the coatings and their substrates upon simultaneous heating by concentrated solar radiant energy fluxes were studied. Well known wear and corrosion resistant TiC-Ni-B and WC-Ni-B coatings 50 to 300 microns thick applied by the slip method to flat or cylindrical stainless steel and titanium specimens were examined. The specimens were heated in an SGU-5 solar heating installation with a 2 m diameter parabolic mirror concentrator in a process chamber with a quartz window under a vacuum. Metallographic analysis revealed a finely dispersed heterogeneous structure with no visible porosity, good bonding of coating to substrate, and uniform distribution of carbide phase in the metal matrix of the TiC-Ni-B coatings on titanium. Results were similar for the other coatings, indicating that concentrated solar energy can produce coatings with satisfactory surface quality, good density, and a framework structure. The coating interacted with the substrate by diffusion. Most of the volume of the substrate underwent no significant changes, indicating good bond strength between coatings and substrate.

Korol, A. A.; Korol, Y. A.; Kasich-Pilipenko, I. Y.; Verkhovodov, P. A.; Dvernyakov, V. S.; Kadyrov, V. K.

1983-08-01

389

Stokes flow between eccentric rotating spheres with slip regime  

NASA Astrophysics Data System (ADS)

The steady axisymmetric flow problem of a viscous fluid contained between two eccentric spheres that rotate about an axis joining their centers with different angular velocities is considered. A linear slip of Basset-type boundary condition at both surfaces of the spherical particle and the container is used. Under the Stokesian assumption, a general solution is constructed from the superposition of basic solutions in the spherical coordinate systems based on the inner solid particle and the spherical container. The boundary conditions on the particle's surface and spherical container are satisfied by a collocation technique. Numerical results for the coupling coefficient acting on the particle are obtained with good convergence for various values of the ratio of particle-to-container radii, the relative distance between the centers of the particle and container, the slip coefficients and the relative angular velocity. In the limiting cases, the numerical values of the coupling coefficient for the solid sphere in concentric position with the container and when the particle is near the inner surface of the container are obtained, and the results are in good agreement with the available values in the literature. The variation of the coupling coefficient with respect the parameters considered are tabulated and displayed graphically.

Faltas, M. S.; Saad, E. I.

2012-10-01

390

Constructing constitutive relationships for seismic and aseismic fault slip  

USGS Publications Warehouse

For the purpose of modeling natural fault slip, a useful result from an experimental fault mechanics study would be a physically-based constitutive relation that well characterizes all the relevant observations. This report describes an approach for constructing such equations. Where possible the construction intends to identify or, at least, attribute physical processes and contact scale physics to the observations such that the resulting relations can be extrapolated in conditions and scale between the laboratory and the Earth. The approach is developed as an alternative but is based on Ruina (1983) and is illustrated initially by constructing a couple of relations from that study. In addition, two example constitutive relationships are constructed; these describe laboratory observations not well-modeled by Ruina's equations: the unexpected shear-induced weakening of silica-rich rocks at high slip speed (Goldsby and Tullis, 2002) and fault strength in the brittle ductile transition zone (Shimamoto, 1986). The examples, provided as illustration, may also be useful for quantitative modeling.

Beeler, N.M.

2009-01-01

391

Slip ratio in dispersed viscous oil-water pipe flow  

SciTech Connect

In this article, dispersed flow of viscous oil and water is investigated. The experimental work was performed in a 26.2-mm-i.d. 12-m-long horizontal glass pipe using water and oil (viscosity of 100 mPa s and density of 860 kg/m{sup 3}) as test fluids. High-speed video recording and a new wire-mesh sensor based on capacitance (permittivity) measurements were used to characterize the flow. Furthermore, holdup data were obtained using quick-closing-valves technique (QCV). An interesting finding was the oil-water slip ratio greater than one for dispersed flow at high Reynolds number. Chordal phase fraction distribution diagrams and images of the holdup distribution over the pipe cross-section obtained via wire-mesh sensor indicated a significant amount of water near to the pipe wall for the three different dispersed flow patterns identified in this study: oil-in-water homogeneous dispersion (o/w H), oil-in-water non-homogeneous dispersion (o/w NH) and Dual continuous (Do/w and Dw/o). The phase slip might be explained by the existence of a water film surrounding the homogeneous mixture of oil-in-water in a hidrofilic-oilfobic pipe. (author)

Rodriguez, Iara H.; Yamaguti, Henrique K.B.; de Castro, Marcelo S.; Rodriguez, Oscar M.H. [Department of Mechanical Engineering, Engineering School of Sao Carlos, University of Sao Paulo (USP), Av. Trabalhador Sao Carlense, 400, 13566-970 Sao Carlos, SP (Brazil); Da Silva, Marco J. [Forschungszentrum Dresden-Rossendorf e. V., Institute of Safety Research, PO Box 510119, 01314 Dresden (Germany)

2011-01-15

392

No-slip pressures in wall bounded flows  

NASA Astrophysics Data System (ADS)

In incompressible flow, the pressure must obey a Poisson equation gotten from the divergence of the Navier-Stokes (NS) equation. But Poisson equations need boundary conditions, and those for the pressure at no-slip walls are Neumann and Dirichlet both. Many time-dependent tricks around this difficulty have been proposed and some seem to work, but the mathematical issue remains: Which, if any, solenoidal velocity fields that vanish at no-slip walls are acceptable as NS initial conditions? We use a family of solenoidal 2D velocity fields that vanish at plane parallel walls and are periodic in the other direction. Pressures may be found analytically, using the normal or tangential boundary conditions on grad p. Similarities and differences are noted, and limits are considered in which the two differ only slightly. Spectral method dynamical computations, like those of Li et al [1] for the circle, seem feasible. [1] S. Li et al, Phys. Lett. A218, 281 (1996) and Theor. & Comp. Fluid Dyn. 9, 167 (1997).

Kress, Brian T.; Montgomery, David C.

1999-11-01

393

Finger Joint Injuries.  

PubMed

Finger joint dislocations and collateral ligament tears are common athletic hand injuries. Treatment of the athlete requires a focus on safe return to play and maximizing function. Certain dislocations, such as proximal interphalangeal and distal interphalangeal volar dislocations, may be associated with tendon injuries and must be treated accordingly. Treatment of other dislocations is ultimately determined by postreduction stability, with many dislocations amenable to nonoperative treatment (ie, immobilization followed by rehabilitation). Protective splinting does not necessarily preclude athletic participation. Minor bone involvement typically does not affect the treatment plan, but significant articular surface involvement may necessitate surgical repair or stabilization. Percutaneous and internal fixation are the mainstays of surgical treatment. Treatment options that do not minimize recovery or allow the patient to return to protected play, such as external fixation, are generally avoided during the season of play. Undertreated joint injuries and unrecognized ligament injuries can result in long term disability. PMID:25455398

Prucz, Roni B; Friedrich, Jeffrey B

2015-01-01

394

Analysis of surface structures of major strike-slip faults  

NASA Astrophysics Data System (ADS)

Strike-slip faults commonly appear with complex fractures and deformation structures on the surface, which also reveal the 3-D geometry with variable structures at depth. The aim of our study is finding the systematic features and correlations of various surface expressions including width, length, height and angle (to the main fault trace) of individual structures like pressure ridges, sag ponds, riedel and anti-riedel faults and oversteps, and also doing a classification with these data. The variation might by caused by distinct convergence angles along strike-slip fault. We study the above mentioned properties on Altyn Tagh fault (ATF), Kunlun, San Andrea and Greendale (Darfield earthquake) faults, which are large strike-slip tectonic structures accommodating major displacement along plate boundaries. Especially the recent events of 2001 Kunlun earthquake and 2010 Darfield earthquake allow a detailed study of structures formed by a single earthquake. Along the fault valley of a 610 km segment of ATF, many large-scale pressure ridges, few pressure basins and horizontal offsets of wadi channels were found; similarly, around 20 features with large scale pressure ridges and pressure basins are found in Carrizo Plain of San Andreas fault. Surface ruptures are uncommon, and dominated by anti-riedels in the case of the Altyn fault. Interpretations show the range of length, width and height in pressure ridges located between 150 and ~6400 m, 35 and ~800 m, and 1 to ~80 m, respectively, along ATF and 255 to ~5750 m, 33 to ~800 m, 2 to ~65 m in Carrizo plain of San Andreas fault. These parameters exhibit a good correlation among each other implying a common cause. Compared with these two strike-slip faults, fault valley portions of the Greendale and Kunlun faults show more surface ruptures for instance riedel shears and anti-riedel structures, which have been caused by the last major earthquake, and also the scale of deformations along the ATF and San Andreas fault is much larger by numerous cumulative earthquakes. Surface ruptures has certain length and width of 5 m to ~200 m, 3 to ~350 m in the Kunlun fault (Lin and Nishikawa, 2011) and 10 to ~450 m, 30 to ~300 m in Greendale fault (Quigley et al., 2012). Beside the scale difference, the statistical approach also applied in the parameters of these surface features, result shows in these four faults, there are specific correlations exist among lengths, width, height and convergence angle which is also the key point to explore the depth of these structures with analog experiments. A likely explanation for the differences between Altyn/San Andreas faults and Kunlun/Glendale fault is the transpressive nature of Altyn/San Andreas faults and the pure strike-slip/transform nature of Glendale/Kunlun faults implying a small convergence angle in the latter case.

Hsieh, Shang Yu; Neubauer, Franz

2013-04-01

395

Prosthetic elbow joint  

NASA Technical Reports Server (NTRS)

An artificial, manually positionable elbow joint for use in an upper extremity, above-elbow, prosthetic is described. The prosthesis provides a locking feature that is easily controlled by the wearer. The instant elbow joint is very strong and durable enough to withstand the repeated heavy loadings encountered by a wearer who works in an industrial, construction, farming, or similar environment. The elbow joint of the present invention comprises a turntable, a frame, a forearm, and a locking assembly. The frame generally includes a housing for the locking assembly and two protruding ears. The forearm includes an elongated beam having a cup-shaped cylindrical member at one end and a locking wheel having a plurality of holes along a circular arc on its other end with a central bore for pivotal attachment to the protruding ears of the frame. The locking assembly includes a collar having a central opening with a plurality of internal grooves, a plurality of internal cam members each having a chamfered surface at one end and a V-shaped slot at its other end; an elongated locking pin having a crown wheel with cam surfaces and locking lugs secured thereto; two coiled compression springs; and a flexible filament attached to one end of the elongated locking pin and extending from the locking assembly for extending and retracting the locking pin into the holes in the locking wheel to permit selective adjustment of the forearm relative to the frame. In use, the turntable is affixed to the upper arm part of the prosthetic in the conventional manner, and the cup-shaped cylindrical member on one end of the forearm is affixed to the forearm piece of the prosthetic in the conventional manner. The elbow joint is easily adjusted and locked between maximum flex and extended positions.

Weddendorf, Bruce C. (inventor)

1994-01-01

396

Laboratory characterization of rock joints  

SciTech Connect

A laboratory characterization of the Apache Leap tuff joints under cyclic pseudostatic and dynamic loads has been undertaken to obtain a better understanding of dynamic joint shear behavior and to generate a complete data set that can be used for validation of existing rock-joint models. Study has indicated that available methods for determining joint roughness coefficient (JRC) significantly underestimate the roughness coefficient of the Apache Leap tuff joints, that will lead to an underestimation of the joint shear strength. The results of the direct shear tests have indicated that both under cyclic pseudostatic and dynamic loadings the joint resistance upon reverse shearing is smaller than that of forward shearing and the joint dilation resulting from forward shearing recovers during reverse shearing. Within the range of variation of shearing velocity used in these tests, the shearing velocity effect on rock-joint behavior seems to be minor, and no noticeable effect on the peak joint shear strength and the joint shear strength for the reverse shearing is observed.

Hsiung, S.M.; Kana, D.D.; Ahola, M.P.; Chowdhury, A.H.; Ghosh, A. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1994-05-01

397

Joint measurements and Bell inequalities  

E-print Network

Joint quantum measurements of non-commuting observables are possible, if one accepts an increase in the measured variances. A necessary condition for a joint measurement to be possible is that a joint probability distribution exists for the measurement. This fact suggests that there may be a link with Bell inequalities, as these will be satisfied if and only if a joint probability distribution for all involved observables exists. We investigate the connections between Bell inequalities and conditions for joint quantum measurements to be possible. Mermin's inequality for the three-particle Greenberger-Horne-Zeilinger state turns out to be equivalent to the condition for a joint measurement on two out of the three quantum systems to exist. Gisin's Bell inequality for three co-planar measurement directions, meanwhile, is shown to be less strict than the condition for the corresponding joint measurement.

Wonmin Son; Erika Andersson; Stephem M. Barnett; M. S. Kim

2005-09-20

398

Evaluating mechanical models for weak fault slip using two low-angle normal faults that slipped at high to moderate angles to the maximum compressive stress  

NASA Astrophysics Data System (ADS)

Paleostress inversion models from minor faults cutting the footwalls of two low-angle normal faults (LANFs) in S. California indicate that slip on these faults occurred while they were oriented at steep to moderate angles to the regional maximum stress direction (S1) at different depths during the evolution of each fault zone. The Whipple detachment fault (WD) slipped ~40-50 km and exposed an early footwall mylonite zone. The West Salton detachment (WSD) slipped ~ 10-15 km and only brittlely damaged footwall rocks are exposed at the surface. S1 paleostress directions from minor faults cutting the fault core, ~0-10 m below the principal slip surface, generally are at high angles to the LANFs (~80-90°), whereas in the deeper damage zone, ~10-30 m below the principal slip surface, S1 is commonly at moderate angles of ~45-60° to the LANFs. We interpret that the minor faults cutting the fault core are the youngest structures in the fault zone but that both young and older faults cut the damage zone. Therefore, paleostress-field inversions support a temporal reorientation of S1 directions during exhumation from deep to shallow seismogenic depths. These LANFs were weak at shallow depths because slip occurred with S1 at steep, Andersonian angles to the faults. Low-friction materials were not found, requiring other mechanisms for slip. Angles of ~30° between S1 and the LANFs were not obtained, ruling out the Rice (1992) model. Shallow slip, at high angle to S1, is allowed by elevated fluid pressure and/or by strength anisotropy in the fault zones (e.g., Axen and Selverstone 1994). Gradual, crustal-scale stress rotation between the brittle-plastic transition (BDT) and the surface (Yin 1989) is preferred for the WD (see Selverstone et al. 2012). Granular flow (Coulomb plasticity) may explain moderate angles between S1 and the WSDF at depth (but above the BDT).

Luther, A. L.; Axen, G. J.; Selverstone, J.

2012-12-01

399

Kilauea slow slip events: Identification, source inversions, and relation to seismicity  

Microsoft Academic Search

Several slow slip events beneath the south flank of Kilauea Volcano, Hawaii, have been inferred from transient displacements in daily GPS positions. To search for smaller events that may be close to the noise level in the GPS time series, we compare displacement fields on Kilauea's south flank with displacement patterns in previously identified slow slip events. Matching displacement patterns

E. K. Montgomery-Brown; P. Segall; A. Miklius

2009-01-01

400

Seismic Moment, Seismicity, and Rate of Slip along Major Fault Zones  

Microsoft Academic Search

A straightforward method for computing rates of slip from earthquakes in major fault zones is presented. The slip rate is calculated from the sum of moments for the earthquakes. Rates obtained are in approximate agreement with rates obtained from geodetic measurements or magnetic anomalies, provided that long time samples are considered and provided that adjustments are made in the vertical

James N. Brune

1968-01-01

401

Slip accumulation and lateral propagation of active normal faults in Afar  

Microsoft Academic Search

We investigate fault growth in Afar, where normal fault systems are known to be currently growing fast and most are propagating to the northwest. Using digital elevation models, we have examined the cumulative slip distribution along 255 faults with lengths ranging from 0.3 to 60 km. Faults exhibiting the elliptical or ``bell-shaped'' slip profiles predicted by simple linear elastic fracture

I. Manighetti; G. C. P. King; Y. Gaudemer; C. H. Scholz; C. Doubre

2001-01-01

402

Geophysical confirmation of low-angle normal slip on the historically active Dixie Valley fault, Nevada  

E-print Network

1 Geophysical confirmation of low-angle normal slip on the historically active Dixie Valley fault Despite growing geological and geophysical evidence arguing for the existence of low-angle normal faults-angle normal-mechanism earthquakes in the seismic record remains. Slip on low-angle normal faults

403

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

E-print Network

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

Cooke, Michele

404

Connecting Earthquakes and Violins: Investigations Illustrate Stick-Slip Frictional Motion as a Common Thread  

ERIC Educational Resources Information Center

Violins, earthquakes, and the "singing rod" demonstration all have something in common--stick-slip frictional motion. The application of stick-slip friction can be extended to a ringing wineglass, exotic percussion instruments, car racing, and the latest research on the interplay between surfaces at the atomic level. These examples all involve two…

Ringlein, James

2005-01-01

405

Slow slip predictions based on granite and gabbro friction data compared to GPS measurements  

E-print Network

Slow slip predictions based on granite and gabbro friction data compared to GPS measurements friction data of granite and gabbro gouges under hydrothermal conditions to a Cascadia-like 2-D model and extrapolating the 2-D fault slip to a 3-D distribution, we find that the friction data for gabbro gouge

406

Private Middle School Parents' Perspectives Regarding School-Located Immunization Programs (SLIPs)  

ERIC Educational Resources Information Center

The perspectives of parents of private middle school students regarding the use of school-located immunization programs (SLIPs) are unknown. Parents of private middle school students in a large, urban setting were surveyed "N" = 1,210) regarding their willingness to use SLIPs. Analyses included frequencies and chi-square analyses. Data…

Venkatesh, Sheila R.; Acosta, Amy B.; Middleman, Amy B.

2013-01-01

407

Giant Slip at Liquid-Liquid Interfaces Using Hydrophobic Ball Bearings  

NASA Astrophysics Data System (ADS)

Liquid-gas-liquid interfaces stabilized by hydrophobic beads behave as ball bearings under shear and exhibit a giant slip. Using a scaling analysis and molecular dynamics simulations we predict that, when the contact angle ? between the beads and the liquid is large, the slip length diverges as R?-1(?-?)-3 where R is the bead radius, and ? is the bead density.

Ehlinger, Quentin; Joly, Laurent; Pierre-Louis, Olivier

2013-03-01

408

Lattice Boltzmann modeling of microchannel flow in slip flow regime Frederik Verhaeghe a  

E-print Network

Lattice Boltzmann modeling of microchannel flow in slip flow regime Frederik Verhaeghe a , Li Keywords: Gas flow through microchannel Slip flow Lattice Boltzmann equation with multiple relaxation times) to simulate pressure-driven gaseous flow in a long microchannel. We obtain analytic solu- tions of the MRT

Luo, Li-Shi

409

Modeling the combined effect of surface roughness and shear rate on slip flow of simple fluids  

E-print Network

Molecular dynamics (MD) and continuum simulations are carried out to investigate the influence of shear rate and surface roughness on slip flow of a Newtonian fluid. For weak wall-fluid interaction energy, the nonlinear shear-rate dependence of the intrinsic slip length in the flow over an atomically flat surface is computed by MD simulations. We describe laminar flow away from a curved boundary by means of the effective slip length defined with respect to the mean height of the surface roughness. Both the magnitude of the effective slip length and the slope of its rate-dependence are significantly reduced in the presence of periodic surface roughness. We then numerically solve the Navier-Stokes equation for the flow over the rough surface using the rate-dependent intrinsic slip length as a local boundary condition. Continuum simulations reproduce the behavior of the effective slip length obtained from MD simulations at low shear rates. The slight discrepancy between MD and continuum results at high shear rates is explained by examination of the local velocity profiles and the pressure distribution along the wavy surface. We found that in the region where the curved boundary faces the mainstream flow, the local slip is suppressed due to the increase in pressure. The results of the comparative analysis can potentially lead to the development of an efficient algorithm for modeling rate-dependent slip flows over rough surfaces.

Anoosheh Niavarani; Nikolai V. Priezjev

2009-08-26

410

Interseismic fault strengthening and earthquake-slip instability: Friction or cohesion?  

Microsoft Academic Search

The slip instability of an earthquake and its abrupt energy release depend primarily on the intensity of strength drop during accelerated fault slip. This process is typically attributed to changes of frictional resistance between two sliding blocks. Here we show that friction changes alone cannot explain observed strength variations of artificial fault zones. Sandstone samples with saw-cut faults and gypsum

Sankar K. Muhuri; Thomas A. Dewers; Thurman E. Scott Jr.; Ze'ev Reches

2003-01-01

411

Determination of the fault slip distribution of the 1976 Tangshan earthquake by the finite element method  

Microsoft Academic Search

A general method for the determination of the coseismic fault slip distribution by inversion of geodetic data is presented. One type of inverse problem and its solutions are investigated by the finite element and regularization methods. The coseismic fault slip vector is expressed by the solutions of the inverse problem of partial differential equations. The proposed method is used to

Shaorong Zhao; Dingbo Chao

1995-01-01

412

Modal and vectorial analysis for determination of stress axes associated with fault slip data  

Microsoft Academic Search

Based on Anderson's faulting theory, for a given set of fault slip data including the sense of slip on faults and fault planes, this paper provides two possible methods to reconstruct the principal stress axes using vectorial and modal analysis procedure. The vectorial analysis consists of computing eigenvectors of the orientation matrices defined by axes P, B, and T (P,

Huang Qin

1989-01-01

413

The synergistic effects of slip ring-brush design and materials  

NASA Technical Reports Server (NTRS)

The design, fabrication, and subsequent testing of four power slip rings for synchronous orbit application are described. The synergistic effects of contact materials and slip ring-brush design are studied by means of frequent and simultaneous recording of friction, wear, and electrical noise. Data generated during the test period are presented along with post test analysis data.

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

1974-01-01

414

"A Chance Child": Jill Paton Walsh and the Re-Invention of the Time Slip Story  

ERIC Educational Resources Information Center

In this study of Jill Paton Walsh's one time-slip novel, I attempt to show how she reinvents the genre by giving as much prominence to the dislocated present as she does to the sufferings of children caught up in the horrors of the Industrial Revolution. Where previous time-slip authors had concentrated on the past, she addresses clearly unwelcome…

Hall, Linda Marian

2011-01-01

415

Interconverting Conformations of Slipped-DNA Junctions Formed by Trinucleotide Repeats Affect Repair Outcome  

PubMed Central

Expansions of (CTG)·(CAG) repeated DNAs are the mutagenic cause of 14 neurological diseases, likely arising through the formation and processing of slipped-strand DNAs. These transient intermediates of repeat length mutations are formed by out-of-register mispairing of repeat units on complementary strands. The three-way slipped-DNA junction, at which the excess repeats slip out from the duplex, is a poorly understood feature common to these mutagenic intermediates. Here, we reveal that slipped junctions can assume a surprising number of interconverting conformations where the strand opposite the slip-out either is fully base paired or has one or two unpaired nucleotides. These unpaired nucleotides can also arise opposite either of the nonslipped junction arms. Junction conformation can affect binding by various structure-specific DNA repair proteins and can also alter correct nick-directed repair levels. Junctions that have the potential to contain unpaired nucleotides are repaired with a significantly higher efficiency than constrained fully paired junctions. Surprisingly, certain junction conformations are aberrantly repaired to expansion mutations: misdirection of repair to the non-nicked strand opposite the slip-out leads to integration of the excess slipped-out repeats rather than their excision. Thus, slipped-junction structure can determine whether repair attempts lead to correction or expansion mutations. PMID:23339280

2013-01-01

416

An imposed numerical analysis of transient two-phase phenomena using a slip model  

Microsoft Academic Search

Results of a combined analytical and experimental effort are presented which studied the behavior of one dimensional piping systems under transient two phase flow conditions. A one dimensional, thermal equilibrium transient two phase analytical model incorporating slip was developed. The model was solved using the method of characteristics. The derivation of equations incorporating slip is presented, and the well-posedness of

A. M. Tentner

1975-01-01

417

Details of Tidally Modulated Stick-Slip Motion of Whillans Ice Stream, West Antarctica  

NASA Astrophysics Data System (ADS)

Whillans Ice Stream remains the only Antarctic ice stream yet reported where most of the motion occurs as stick-slip. Continued study of this ice stream has revealed a number of other interesting characteristics: the fraction of mean daily motion accomplished by these slips is approximately 90% near the grounding line and decreases upstream; the motion on the ice plain is larger during spring tides than during neap tides, but the slip fraction is constant; and near the grounding line, slip events begin and end more impulsively that farther upstream. Additionally, the mean annual velocity continues to decrease and the slip fraction of daily motion increased from 2003-04 to 2004-05 due to an increase in the slip displacements. Dense grids of GPS receivers and seismometers were established in the mouth of Whillans Ice Stream for approximately one month during the 2004-2005 Antarctic field season to examine further details of these stick-slip characteristics. GPS receivers spaced approximately 25 km apart formed a background grid while a set of mobile receivers were moved to gain a finer resolution picture of the stick-slip phenomenon at specific locations. A majority of the events appear to initiate in a single local and propagate upstream and downstream. Data processing is ongoing. We expect to be able to address issues of propagation speed and mechanism, till properties and the initiation mechanism.

Bindschadler, R.; Anandakrishnan, S.; Voigt, D.; Joughin, I.; Alley, R.; King, M.; Winberry, P.; Peters, L.; Horgan, H.

2005-12-01

418

Volcanic drumbeat seismicity caused by stick-slip motion and magmatic frictional melting  

NASA Astrophysics Data System (ADS)

During volcanic eruptions, domes of solidifying magma can form at the volcano summit. As magma ascends it often forms a plug bounded by discrete fault zones, a process accompanied by drumbeat seismicity. The repetitive nature of this seismicity has been attributed to stick-slip motion at fixed loci between the rising plug of magma and the conduit wall. However, the mechanisms for such periodic motion remain controversial. Here we simulate stick-slip motion in the laboratory using high-velocity rotary-shear experiments on magma-dome samples collected from Soufrière Hills Volcano, Montserrat, and Mount St Helens Volcano, USA. We frictionally slide the solid magma samples to generate slip analogous to movement between a magma plug and the conduit wall. We find that frictional melting is a common consequence of such slip. The melt acts as a viscous brake, so that the slip velocity wanes as melt forms. The melt then solidifies, followed by pressure build up, which allows fracture and slip to resume. Frictional melt therefore provides a feedback mechanism during the stick-slip process that can accentuate the cyclicity of such motion. We find that the viscosity of the frictional melt can help define the recurrence interval of stick-slip events. We conclude that magnitude, frequency and duration of drumbeat seismicity depend in part on the composition of the magma.

Kendrick, J. E.; Lavallée, Y.; Hirose, T.; di Toro, G.; Hornby, A. J.; de Angelis, S.; Dingwell, D. B.

2014-06-01

419

Dexterous electron hydraulic servo manipulator based on opto-electronic slip sensor  

Microsoft Academic Search

It is challenging with the hydraulic servo manipulators to achieve soft grasping. It needs the servo-control on the manipulator's precise position and clamping force. Slip sensor is very important in the process of the manipulator's grasp .The micro-vibration measurement based slip sensor employs the elastomer and the photoelectric apparatus installed in the manipulator to detect the slide at the moment

Zhen-Dong Shang; Zhigang Hu; Qinghua Zhang

2010-01-01

420

Overview of cenozoic strike-slip displacement of the caribbean plate  

SciTech Connect

Geologic and tectonic studies in the Caribbean region have traditionally focused on Cretaceous and Paleogene arc rocks which, for the most part, record a long period (approx. = 100 Ma) of plate convergence. Since the recognition of the plate structure of the Caribbean by Molnar and Sykes in 1969, there has been steadily increasing interest in mapping widespread ares of Neogene sedimentary and volcanic rocks that generally record a long period (65.-40 Ma) of eastward displacement of the Caribbean plate relative to the Americas. The purpose of this talk is to review different aspects of present knowledge on this strike-slip displacement, namely: 1) location of major strike-slip faults within the northern and southern plate boundary zones; 2) sense, offset, rate of slip of major strike-slip faults; 3) secondary deformational features related to strike-slip displacements; 4) intraplate deformational features related to interplate strike-slip movements; 5) relation of seismicity to major strike-slip faults; and 6) constraints imposed by strike-slip fault systems on plate motion models. Based on these observations, several critical problems which future studies might help resolve are pointed out.

Mann, P.

1985-01-01

421

Scaling Relationships for Slow Slip Events and Tremor in Subduction Zones  

Microsoft Academic Search

Global compilations of faulting parameters for slow slip phenomena in subduction zones reveal that event duration is proportional to seismic moment rather than its cube-root, as for earthquakes (Schwartz and Rokosky, 2007; Ide et al., 2007). Ide et al. (2007) proposed two different models consistent with this scale dependent behavior that either assume direct proportionality between fault slip (d) and

S. Y. Schwartz; J. M. Rokosky; K. Obara

2007-01-01

422

Evidence for and implications of self-healing pulses of slip in earthquake rupture  

Microsoft Academic Search

Dislocation time histories of models derived from waveforms of seven earthquakes are discussed. In each model, dislocation rise times (the duration of slip for a given point on the fault) are found to be short compared to the overall duration of the earthquake (~ 10%). However, in many crack-like numerical models of dynamic rupture, the slip duration at a given

Thomas H. Heaton

1990-01-01

423

Study of the pore structure of ceramics prepared by the slip casting method  

NASA Technical Reports Server (NTRS)

The porosity of the slip cast Si3N4 is similar to that of pressed Si3N4 formed at 2500 kg/sq cm. The porosity of cast Si oxynitride is equivalent to that of samples stressed at 10,000 kg/sq cm. Crucibles formed from these materials by slip casting have high thermal shock and corrosion resistance.

Guzman, I. Y.; Dobysh, A. V.

1984-01-01

424

Detailed coseismic slip distribution of the 1944 Tonankai earthquake estimated from tsunami waveforms  

Microsoft Academic Search

Coseismic slip distribution on the fault plane of the 1944 Tonankai earthquake is estimated from inversion of tsunami waveforms. Three improvements from a previous study [Satake, 1993] are made. These are: (1) smaller subfaults are used to resolve detailed slip distribution; (2) the subfaults fit better to the plate interface geometry; and (3) finer and more accurate bathymetry data is

Yuichiro Tanioka; Kenji Satake

2001-01-01

425

The influence of wall slip in the measurement of solder paste viscosity  

Microsoft Academic Search

The wall slip phenomena is known to have a significant effect on the measurement of the viscosity of dense suspensions. In the measurement of the viscosity of solder pastes the effect of wall slip is such that the measured viscosity (also called the apparent viscosity) is much lower than the true viscosity of the paste. Therefore, correction needs to be

N. N. Ekere; D. He; L. Cai

2001-01-01

426

Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area  

DOE Data Explorer

Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Slip and dilation tendency for the Tuscarora geothermal field was calculated based on the faults mapped Tuscarora area (Dering, 2013). The Tuscarora area lies in the Basin and Range Province, as such we applied a normal faulting stress regime to the Tuscarora area faults, with a minimum horizontal stress direction oriented 115, based on inspection of local and regional stress determinations, as explained above. Under these stress conditions north-northeast striking, steeply dipping fault segments have the highest dilation tendency, while north-northeast striking 60° dipping fault segments have the highest tendency to slip. Tuscarora is defined by a left-step in a major north- to-north northeast striking, west-dipping range-bounding normal fault system. Faults within the broad step define an anticlinal accommodation zone...

Faulds, James E.

427

Influence of groove count on slip resistance using NTL test feet.  

PubMed

In recent years, walkway slip-resistance testing with grooved NTL (Neolite Test Liners) has been the subject of research, as well as used in field investigation practices. Recent research shows that differences between non-grooved and grooved test feet do exist, especially under wet conditions. It is not known how the number of grooves influences the slip resistance. This study investigates the influence of groove count on slip resistance under both wet and dry conditions using the PIAST tribometer. Test feet with 1, 3, 5, 7, 9, 11, 13, and 15 grooves and a non-grooved test foot were used. Polished granite and vinyl composition tile were used as test surfaces. Results for both test surfaces show markedly higher slip resistance for increasing groove counts under wet conditions, while under dry conditions, the results show slight increases in slip resistance. Implications of these results are discussed. PMID:16225222

Joganich, Tim; Mc Cuen, Len

2005-09-01

428

Slip on the Suckling Hills splay fault during the 1964 Alaska earthquake  

NASA Astrophysics Data System (ADS)

The Suckling Hills in southern Alaska experienced localized, anomalously large coseismic uplift in the Mw 9.2, 1964 Alaska earthquake. Large uplift at the Suckling Hills can be explained by increased slip, or an asperity, on the Alaska-Aleutian megathrust; however, this paper suggests that increased uplift may be a result of slip on the Suckling Hills splay fault. We present a series of models that demonstrate how the inclusion of the Suckling Hills fault improves the fit between modeled vertical displacement and measured coseismic uplift in comparison to slip on the Alaska-Aleutian megathrust alone. Our results suggest that ~ 3 m of average slip on the Suckling Hills fault during the 1964 earthquake can help explain the large coseismic uplift data. These results are consistent with recent studies indicating Pleistocene slip on the Suckling Hills fault and together highlight the potential seismic and tsunami risk associated with this segment of the Alaskan subduction complex.

Chapman, James B.; Elliott, Julie; Doser, Diane I.; Pavlis, Terry L.

2014-12-01

429

Shortening of recurrence interval of Boso slow slip events in Japan  

NASA Astrophysics Data System (ADS)

slow slip event occurred off the coast of the Boso peninsula, Japan, from approximately 28 December 2013 to 10 January 2014. The estimated aseismic slip expanded slightly southward and westward over time with a moment magnitude of 6.5, which was the smallest value since 1996. The recurrence interval has decreased from approximately 6.4 to 2.2 years from 1996 to 2014. One explanation of this shortening is the change in Coulomb failure stress due to the 2011 Mw9.0 Tohoku earthquake and its afterslip. Another interpretation is related to a scenario observed in several numerical simulation studies, in which the recurrence interval of slow slip becomes shorter as the time nears a large earthquake. This case will constrain the physical processes of a slip cycle. The Boso slow slip events together with the Tohoku earthquake and its afterslip changed the stress state for the anticipated interplate earthquake near the Sagami trough.

Ozawa, Shinzaburo

2014-04-01

430

Fault constitutive relations inferred from the 2009-2010 slow slip event in Guerrero, Mexico  

NASA Astrophysics Data System (ADS)

The spatiotemporal evolution of stress state is analyzed during the 2009-2010 Slow Slip Event (SSE) of Guerrero, Mexico, based on the kinematic inversion results and using an integral expression for stress changes. A linear slip weakening behavior is generally observed during the SSE with an average slope of -0.5 ± 0.2MPa/m regardless the perturbation due to the 27 February 2010 Mw = 8.8 Maule, Chile earthquake. This slope remains unchanged before and after the Maule earthquake. However, for some area, the friction behavior changes from slip hardening to slip weakening following the Maule earthquake. The complex trajectory between shear stress and slip velocity is fitted with a rate- and state friction law through an inversion. The direct (rate) effect (parameter A) is found to be very small, lower by an order of magnitude than the evolutional (state) effect (parameter B). The characteristic length L is obtained as 5 cm on average.

Maury, Julie; Aochi, Hideo; Radiguet, Mathilde

2014-07-01

431

An alternative interpretation for slip vector residuals of subduction interface earthquakes: a case study in the westernmost Ryukyu slab  

E-print Network

An alternative interpretation for slip vector residuals of subduction interface earthquakes: a case by slip vector residuals determined from interface earthquakes. It is measured through contrasting deformation; minimum deformation rate kinematics 1. Introduction The majority of earthquakes in subduction

Demouchy, Sylvie

432

Equine hoof slip distance during trot at training speed: comparison between kinematic and accelerometric measurement techniques.  

PubMed

Longitudinal sliding of horse's hooves at the beginning of stance can affect both performance and orthopaedic health. The objective of this study was to compare two measurement methods for quantifying hoof slip distances at training trot. The right front hoof of four French Trotters was equipped with an accelerometer (10 kHz) and kinematic markers. A firm wet sand track was equipped with a 50 m calibration corridor. A high-frequency camera (600 Hz) was mounted in a vehicle following each horse trotting at about 7 m/s. One of the horses was also trotted on raw dirt and harrowed dirt tracks. Longitudinal slip distance was calculated both from kinematic data, applying 2D direct linear transformation (2D-DLT) to the markers image coordinates, and from the double integration of the accelerometer signal. For each stride, both values were compared. The angle of the hoof with respect to the track was also measured. There was 'middling/satisfactory' agreement between accelerometric and 2D-DLT measurements for total slip and 'fairly good' agreement for hoof-flat slip. The influence of hoof rotation on total slip distance represented <6% of accelerometric measures. The differences between accelerometric and kinematic measures (from -0.5 cm to 2.1cm for total slip and from -0.2 cm to 1.4 cm for hoof-flat slip) were independent of slip distance magnitude. The accelerometric method was a simple method to measure hoof slip distances at a moderate training speed trot which may be useful to compare slip distances on various track surfaces. PMID:23489849

Holden-Douilly, Laurène; Pourcelot, Philippe; Desquilbet, Loïc; Falala, Sylvain; Crevier-Denoix, Nathalie; Chateau, Henry

2013-08-01

433

Slow Slip Event and Interseismic Strain Accumulation in the Nicoya Peninsula, Costa Rica  

NASA Astrophysics Data System (ADS)

Slow Slip Events (SSEs) are series of earthquake-like events that release seismic energy over a period of hours to months. They are commonly observed at the subduction zone plate interface where an oceanic plate subducts beneath a continental plate. They can be recorded by nearby continuously operating GPS (C-GPS) networks. A C-GPS network has operated in the Nicoya Peninsula of northern Costa Rica since 2002. The network observes surface displacements above the subduction zone between Cocos and Caribbean plate, and has detected strain accumulation and SSEs along part of the plate boundary. We reprocessed all available data from this network for the period of 2002-2011 to investigate the occurrence of SSE on the subduction interface. Time series analysis of the CGPS data shows that transient deformation imparts a signature similar to random walk. Removal of the SSEs and regional common mode errors from the time series reduces velocity uncertainty by nearly an order of magnitude. We invert observed surface displacements of nine SSEs during 2002-2011 to estimate slip distribution on the plate interface, and assess their impact on the interseismic strain accumulation process. Our inversion results show that maximum slip area of all the SSEs is distributed in areas where no interseismic coupling is not occurring. Three primary slip patches are identified for the nine events, with different slip magnitudes and recurrence intervals. The accumulated slip deficit from all the SSEs accounts for about 20% of the total slip accumulated during the interseismic period. A significant amount of strain in the deeper (40-50 km) part of the subduction zone was released by the SSEs, presumably reducing the amount of future deep seismic slip. Comparison with coseismic slip from the Hojacha earthquake in September 2012 suggests that the remaining slip deficit has been completely released.

Jiang, Y.; McCaffrey, R.; Dixon, T. H.; Wdowinski, S.; Protti, M.; Gonzalez, V. M.

2013-05-01

434

Surgical results of the slipped medial rectus muscle after hang back recession surgery  

PubMed Central

AIM To analyze the surgical results of a slipped medial rectus muscle (MRM) after hang back recession surgery for esotropia. METHODS Twenty-one patients who underwent re-exploration for diagnosed slipped muscle after hang back recession surgery were included in this retrospective study. Dynamic magnetic resonance imaging was performed to identify the location of the slipped muscle. Ocular motility was evaluated with assessment with prism and cover test in gaze at cardinal positions. The operations were performed by the same consultant. Intraoperative forced duction test was performed under general anesthesia. The empty sheath of the slipped MRM was resected and the muscle was advanced to the original insertion site in all patients. RESULTS The average age of 21 patients who had consecutive exotropia with a slipped MRM at the time of presentation was 17.4±5.4y (5-50y). The average duration between the first operation and the diagnosis of the slipped muscle was 25mo (12 to 36mo). The mean follow up after the corrective surgery was 28mo. The mean preoperative adduction limitation in the field of action of the slipped muscle was -2.26 (ranging from -1 to -4). All patients had full adduction postoperatively. CONCLUSION The diagnosis of the slipped muscle should be confirmed during the strabismus surgery. The slipped muscle may be caused due to insufficient suture and excessive rubbing of the eye. When divergent strabismus is observed after the recession of the MRM, a slipped muscle should be considered in the differential diagnosis.

Duranoglu, Yasar; Ilhan, Hatice Deniz; Guler Alis, Meryem

2014-01-01