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1

Strength of transversely isotropic rocks  

E-print Network

This thesis proposes a new Anisotropic Matsuoka-Nakai (AMN) criterion to characterize the failure of transversely isotropic rocks under true triaxial stress states. One major obstacle in formulating an anisotropic criterion ...

Pei, Jianyong, 1975-

2008-01-01

2

Transverse strength of SCS6 silicon carbide fibers  

Microsoft Academic Search

A diametral compression test was used to measure the transverse strength of SCS-6 SiC fibers before and after heat treatment. Subjecting fibers to diametral compression successfully produced transverse tensile failure in the form of fiber cracking along the same diametral plane in which the compressive load was applied. An analysis of the hoop stress along the diametral plane, in which

Jeffrey I. Eldridge; Jonathan P. Wiening; Terry S. Davison; Marek-Jerzy Pindera

1993-01-01

3

In Vitro Study of Transverse Strength of Fiber Reinforced Composites  

PubMed Central

Objective Reinforcement with fiber is an effective method for considerable improvement in flexural properties of indirect composite resin restorations. The aim of this in-vitro study was to compare the transverse strength of composite resin bars reinforced with pre-impregnated and non-impregnated fibers. Materials and Methods Thirty six bar type composite resin specimens (3󫎾5 mm) were constructed in three groups. The first group was the control group (C) without any fiber reinforcement. The specimens in the second group (P) were reinforced with pre-impregnated fibers and the third group (N) with non-impregnated fibers. These specimens were tested by the three-point bending method to measure primary transverse strength. Data were statistically analyzed with one way ANOVA and Tukey抯 tests. Results There was a significant difference among the mean primary transverse strength in the three groups (P<0.001). The post-hoc (Tukey) test showed that there was a significant difference between the pre-impregnated and control groups in their primary transverse strength (P<0.001). Regarding deflection, there was also a significant difference among the three groups (P=0.001). There were significant differences among the mean deflection of the control group and two other groups (PC&N<.001 and PC&P=.004), but there was no significant difference between the non-and pre-impregnated groups (PN&P=.813). Conclusion Within the limitations of this study, it was concluded that reinforcement with fiber considerably increased the transverse strength of composite resin specimens, but impregnation of the fiber used implemented no significant difference in the transverse strength of composite resin samples. PMID:22457836

Mosharraf, R.; Hashemi, Z.; Torkan, S.

2011-01-01

4

Stress-rupture strength and microstructural stability of W-HF-C wire reinforced superalloy composites  

NASA Technical Reports Server (NTRS)

W-Hf-C/superalloy composites were found to be potentially useful for turbine blade applications on the basis of stress-rupture strength. The 100-and 1000-hour rupture strengths obtained for 70 volume percent fiber composites tested at 1090 C were 420 and 280 MN/sq m (61,000 and 41,000 psi). The investigation indicated that with better quality fibers, composites having 100- and 1000-hour rupture strengths of 570 and 370 MN/sq m (82,000 and 54,000 psi) may be obtained. Metallographic studies indicated sufficient fiber-matrix compatibility for long time applications at 1090 C for 1000 hours or more.

Petrasek, D. W.; Signorelli, R. A.

1974-01-01

5

Influence of Florida 301 wheat in a laying hen diet on egg yolk rupture strength.  

PubMed

A study was designed to determine whether wheat could be substituted for corn without reducing yolk quality and yolk membrane strength. Diets with either corn or Florida 301 wheat as the grain source were fed to 50-wk-old hens (140 per diet). Eggs were collected and stored at 10 C for up to 4 wk or at 23 C for 1 wk. At weekly intervals Haugh units, yolk index, yolk rupture strength, and yolk deformation distance at rupture were measured and compression percentages were calculated. Haugh units and yolk index were not affected by diet. Yolk rupture strength and deformation were 12.3% and 4.7% greater, respectively, for eggs from hens on the wheat diet than for those from hens on the corn diet. Both rupture strength and deformation declined significantly with storage. Eggs stored at 23 C were lower in yolk rupture strength and deformation than those held at 10 C. Percentage of compression at rupture also declined with storage, but the decline was initially more rapid for egg yolks from birds fed the corn diet than for egg yolks from birds fed the wheat diet. It was concluded that Florida 301 wheat may be substituted for corn without incurring any problems in the quality of the yolk and that yolk breaking strength would be enhanced. PMID:3684864

Woodward, S A; Fluck, R C; Ouart, M D; Janky, D M

1987-08-01

6

Metal-induced cell rupture in elongating roots is associated with metal ion binding strengths  

Microsoft Academic Search

Low concentrations of Al, Cu and La rapidly decrease root elongation and cause transverse ruptures to the rhizodermis and\\u000a outer cortex, but it is not known if other trace metals have similar effects. Six trace metals, Ga, Gd, Hg, In, Ru, and Sc,\\u000a decreased cowpea root growth and caused ruptures similar to those caused by Al, Cu and La. Calculated

P. M. Kopittke; B. A. McKenna; F. P. C. Blamey; J. B. Wehr; N. W. Menzies

2009-01-01

7

Prediction of residual tensile strength of transversely impacted composite laminates  

NASA Technical Reports Server (NTRS)

The response to low velocity impact of graphite-epoxy T300/5208 composite laminates is discussed. Steel balls of 3/8 inch, 5/8 inch, and 1 inch diameter were the projectiles. Impact energy was limited to 1.2 joules. Impacted specimens were ultrasonically C scanned to determine the impact damaged region. The threshold value of impact energy for impact damage was found to be approximately 0.3 joules. A model was developed to predict the tensile residual strength of impact damaged specimens from fracture mechanics concepts. Impacted specimens were tested in tension to provide a fracture data base. The experimental results agreed well with the predictions from fracture mechanics. In this study, the maximum impact velocity used to simulate the low velocity transverse impact from common objects like tool drops was 10 m/s.

Lal, K. M.

1982-01-01

8

Influence of Specimen Preparation and Specimen Size on Composite Transverse Tensile Strength and Scatter  

NASA Technical Reports Server (NTRS)

The influence of specimen polishing, configuration, and size on the transverse tension strength of two glass-epoxy materials, and one carbon-epoxy material, loaded in three and four point bending was evaluated. Polishing machined edges, arid/or tension side failure surfaces, was detrimental to specimen strength characterization instead of yielding a higher, more accurate, strength as a result of removing inherent manufacture and handling flaws. Transverse tension strength was typically lower for longer span lengths due to the classical weakest link effect. However, strength was less sensitive to volume changes achieved by increasing specimen width. The Weibull scaling law typically over-predicted changes in transverse tension strengths in three point bend tests and under-predicted changes in transverse tension strengths in four point bend tests. Furthermore, the Weibull slope varied with specimen configuration, volume, and sample size. Hence, this scaling law was not adequate for predicting transverse tension strength of heterogeneous, fiber-reinforced, polymer matrix composites.

OBrien, T. Kevin; Chawan, Arun D.; DeMarco, Kevin; Paris, Isabelle

2001-01-01

9

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

10

Creep rupture strength of activated-TIG welded 316L(N) stainless steel  

NASA Astrophysics Data System (ADS)

316L(N) stainless steel plates were joined using activated-tungsten inert gas (A-TIG) welding and conventional TIG welding process. Creep rupture behavior of 316L(N) base metal, and weld joints made by A-TIG and conventional TIG welding process were investigated at 923 K over a stress range of 160-280 MPa. Creep test results showed that the enhancement in creep rupture strength of weld joint fabricated by A-TIG welding process over conventional TIG welding process. Both the weld joints fractured in the weld metal. Microstructural observation showed lower ?-ferrite content, alignment of columnar grain with ?-ferrite along applied stress direction and less strength disparity between columnar and equiaxed grains of weld metal in A-TIG joint than in MP-TIG joint. These had been attributed to initiate less creep cavitation in weld metal of A-TIG joint leading to improvement in creep rupture strength.

Sakthivel, T.; Vasudevan, M.; Laha, K.; Parameswaran, P.; Chandravathi, K. S.; Mathew, M. D.; Bhaduri, A. K.

2011-06-01

11

Stress-rupture strength and microstructural stability of tungsten-hafnium-carbon-wire reinforced superalloy composites  

NASA Technical Reports Server (NTRS)

Tungsten-hafnium-carbon - superalloy composites were found to be potentially useful for turbine blade applications on the basis of stress-rupture strength. The 100- and 1000-hr rupture strengths calculated for 70 vol. % fiber composites based on test data at 1090C (2000F) were 420 and 280 MN/m2 (61,000 and 41,000 psi, respectively). The investigation indicated that, with better quality fibers, composites having 100- and 1000-hr rupture strengths of 570 and 370 MN/m2 (82,000 and 54,000 psi, respectively), may be obtained. Metallographic studies indicated sufficient fiber-matrix compatibility for 1000 hr or more at 1090C (2000F).

Petrasek, D. W.; Signorelli, R. A.

1974-01-01

12

Rupture Strength of Several Nickel-base Alloys in Sheet Form  

NASA Technical Reports Server (NTRS)

The 100-hour rupture strengths of Inconel X, Inconel 700, Incoloy 901, Refractaloy 26, and R-235 at 1200 and 1350 F. in both the annealed and heat-treated conditions were determined. Inconel 700 had the highest rupture strength at both temperatures; Incoloy 901 was second strongest at 1200 F, and R-235 second strongest at 1350 F. With the exception of Incoloy 901, ductility was low. Photomicrographs show that fractures are through the grain boundaries. Results are compared with published data for other sheet alloys and bar stock.

Dance, James H; Clauss, Francis J

1957-01-01

13

Composite Stress Rupture: A New Reliability Model Based on Strength Decay  

NASA Technical Reports Server (NTRS)

A model is proposed to estimate reliability for stress rupture of composite overwrap pressure vessels (COPVs) and similar composite structures. This new reliability model is generated by assuming a strength degradation (or decay) over time. The model suggests that most of the strength decay occurs late in life. The strength decay model will be shown to predict a response similar to that predicted by a traditional reliability model for stress rupture based on tests at a single stress level. In addition, the model predicts that even though there is strength decay due to proof loading, a significant overall increase in reliability is gained by eliminating any weak vessels, which would fail early. The model predicts that there should be significant periods of safe life following proof loading, because time is required for the strength to decay from the proof stress level to the subsequent loading level. Suggestions for testing the strength decay reliability model have been made. If the strength decay reliability model predictions are shown through testing to be accurate, COPVs may be designed to carry a higher level of stress than is currently allowed, which will enable the production of lighter structures

Reeder, James R.

2012-01-01

14

DEM Simulation of Direct Shear: 2. Grain Boundary and Mineral Grain Strength Component Influence on Shear Rupture  

NASA Astrophysics Data System (ADS)

The influence of mineral grain and grain boundary strength is investigated using a calibrated intact (non-jointed) brittle rock specimen subjected to direct shear with a particle-based distinct element method and its embedded grain-based method. The adopted numerical approach allows one to independently control the grain boundary and mineral grain strength. The investigation reveals that, in direct shear, the normal stress ( ? n) applied to a rock specimen relative to its uniaxial compressive strength (UCS) determines the resulting rupture mechanism, the ultimate rupture zone geometry, and thus its shear stress versus horizontal displacement response. This allows one to develop a rupture matrix based on this controlling parameter (i.e., ? n/UCS). Mineral grain strength reductions result in the lowering of the apparent cohesion intercept of the peak linear Coulomb strength envelope, while grain boundary strength reductions change the peak linear Coulomb strength envelope to a bi-linear or curved shape. The impact of grain boundary strength is only relevant at ? n/UCS ratios <0.17 where tensile and dilatant rupture mechanisms dominate. Once shear rupture begins to be the dominant rupture mechanism in a brittle rock (i.e., at ? n/UCS ratios >0.17), the influence of weakened grain boundaries is minimized and strength is controlled by that of the mineral grains.

Bewick, R. P.; Kaiser, P. K.; Bawden, W. F.

2014-09-01

15

Stress-rupture strength and microstructural stability of W-HF-C wire-reinforced superalloy composites  

NASA Technical Reports Server (NTRS)

W-Hf-C superalloy composites were found to be potentially useful for turbine-blade applications on the basis of stress-rupture strength. The 100- and 1000-hour rupture strengths obtained for 70 volume percent fiber composites tested at 1090 C were 420 and 280 MN/sq m. The investigation indicated that with better quality fibers, composites having 100- and 1000-hour rupture strengths of 570 and 370 MN/sq m may be obtained. Metallographic studies indicated sufficient fiber-matrix compatibility for long-term applications at 1090 C for 1000 hours or more.

Petrasek, D. W.; Signorelli, R. A.

1974-01-01

16

Statistical scaling relationships and size effects in the strength and creep rupture of fibrous composites  

NASA Technical Reports Server (NTRS)

In this presentation we discuss a new theoretical model and supporting experimental results for the strength and lifetime in creep rupture of unidirectional, carbon fiber/epoxy matrix composites at ambient conditions. First we review the 'standard' Weibull/power-law methodology that has been standard practice. Then we discuss features of a recent model which build on the statistical aspects of fiber strength, micromechanical aspects of stress transfer around fiber breaks, and time-dependent creep of the matrix. The model is applied to 'microcomposites' consisting of seven fibers in a matrix for which strength and creep-rupture data are available. The model yields Weibull distributions in an envelope format for both strength and lifetime. The respective shape, scale and power-law parameters depend on such parameters as the Weibull shape parameter for fiber strength, the exponent for matrix creep, the effective load transfer length (which grows in time due to matrix creep) and the critical cluster size for failed fibers. The experimental results are consistent with the theory, though time-dependent debonding appears to be part of the failure process.

Phoenix, S. Leigh

1994-01-01

17

Effect of specimen size and shape on creep rupture behavior of creep strength enhanced ferritic steel welds  

Microsoft Academic Search

The creep strength enhanced ferritic (CSEF) steels such as Grades 91, 92, 122, 911, 23 and 24 have become very important key materials for high efficiency fossil-fired power plants for last decades, however the long-term creep rupture strength and strength reduction in welds due to Type IV failure of these steels are serious problem to be urgently resolved. In order

Fujimitsu Masuyama

2010-01-01

18

Transverse tensile and stress rupture properties of gamma/gamma prime-delta directionally solidified eutectic  

NASA Technical Reports Server (NTRS)

Tensile and stress rupture properties were determined primarily at 760 C for specimens oriented at various angles (0 deg, 10 deg, 45 deg, and 90 deg) from the solidification direction of bars and/or slabs of the Ni-20Cb-6Cr-2.5A (gamma/gamma prime-delta) eutectic. Threaded-head specimens yielded longer rupture lives with significantly less scatter than did tapered-head specimens. Miniature specimens are suitable for determining traverse tensile and rupture properties of 1.2 centimeter diameter bar stock. The 300 hour rupture stress at 760 C for specimens oriented at 10 deg from the solidification direction was reduced from 740 to 460 MPa, and to 230 MPa for material oriented at either 45 deg or 90 deg.

Gray, H. H.

1976-01-01

19

Influence of Specimen Preparation and Specimen Size on the Transverse Tensile Strength and Scatter of Glass Epoxy Laminates  

NASA Technical Reports Server (NTRS)

The influence of specimen polishing, specimen configuration, and specimen size on the transverse tension strength of two glass epoxy materials loaded in three and four point bending was evaluated. Polishing machined edges, and/or tension side failure surfaces, was detrimental to specimen strength characterization instead of yielding a higher, more accurate, strength as a result of removing inherent manufacture and handling flaws. Transverse tension strength was sensitive to span length due to the classical weakest link effect. However, strength was less sensitive to volume changes achieved by increasing specimen width. The Weibull scaling law over-predicted changes in transverse tension strengths in three point bend tests and under-predicted changes in transverse tension strengths in four point bend tests. Furthermore, the Weibull slope varied with specimen configuration, volume, and sample size. Hence, the utility of this scaling law for predicting transverse tension strength is unclear.

OBrien, T. Kevin; Chawan, Arun D.; DeMarco, Kevin

1999-01-01

20

Scale effects on the transverse tensile strength of graphite epoxy composites  

NASA Technical Reports Server (NTRS)

The influence of material volume on the transverse tensile strength of AS4/3501-6 graphite epoxy composites was investigated. Tensile tests of 90 degree laminates with 3 different widths and 5 different thicknesses were conducted. A finite element analysis was performed to determine the influence of the grip on the stress distribution in the coupons and explain the tendency for the distribution of failure locations to be skewed toward the grip. Specimens were instrumented with strain gages and extensometers to insure good alignment and to measure failure strains. Data indicated that matrix dominated strength properties varied with the volume of material that was stressed, with the strength decreasing as volume increased. Transverse strength data were used in a volumetric scaling law based on Weibull statistics to predict the strength of 90 degree laminates loaded in three point bending. Comparisons were also made between transverse strength measurements and out-of-plane interlaminar tensile strength measurements from curved beam bending tests. The significance of observed scale effects on the use of tests for material screening, quality assurance, and design allowables is discussed.

Obrien, T. Kevin; Salpekar, Satish A.

1992-01-01

21

Effect of low transverse magnetic field on the confinement strength in a quasi-1D wire  

SciTech Connect

Transport measurements in a quasi-one dimensional (1D) quantum wire are reported in the presence of low transverse magnetic field. Differential conductance shows weak quantised plateaus when the 2D electrons are squeezed electrostatically. Application of a small transverse magnetic field (0.2T) enhances the overall degree of quantisation due to the formation of magneto-electric subbands. The results show the role of magnetic field to fine tune the confinement strength in low density wires when interaction gives rise to double row formation.

Kumar, Sanjeev [London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Thomas, K. J. [London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK and Department of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Smith, L. W.; Farrer, I.; Ritchie, D. A.; Jones, G. A. C.; Griffiths, J. [Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 OHE (United Kingdom); Pepper, M. [London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK and Department of Electrical and Electronic Engineering, Torrington Place, London WC1E 7JE (United Kingdom)

2013-12-04

22

Transversal electrostatic strength of patterned collector affecting alignment of electrospun nanofibers  

NASA Astrophysics Data System (ADS)

Conventional electrospinning produces randomly ordered nanofibers, however many potential applications require precisely defined morphology and anisotropic properties of nanofibrous materials. In this work, a collector consisting of two segments has been used to prepare uniaxially ordered nanofibers. Optimized collector design comes from both analytical calculations of electrostatic strength in the vicinity of the electrodes and from experimental verification by polyvinyl alcohol nanofibers fabrication. The transversal electric strength is a key factor in achieving very well aligned nanofibers. The results presented here help provide a better understanding of the electrically induced alignment mechanism.

Pokorny, Marek; Niedoba, Krzysztof; Velebny, Vladimir

2010-05-01

23

Effect of transverse reinforcement on bond strength of reinforcing bars in silica fume concrete  

Microsoft Academic Search

The objectives of the research program were to investigate the effect of transverse reinforcement on the bond-slip characteristics\\u000a of tension lap splices in high performance silica fume concrete, to study the validity of the upper limit of 70 MPa imposed\\u000a by the ACI Building Code 318-95 on the concrete compressive strength for determination of development length, and to evaluate\\u000a the

B. S. Hamad; M. F. Machaka

1999-01-01

24

Effect of five woven fiber reinforcements on the impact and transverse strength of a denture base resin  

Microsoft Academic Search

Statement of problem. Fracture strength of denture base resins is of great concern, and many approaches have been used to strengthen acrylic resin dentures. Purpose. This study measured the effect of 5 fiber strengtheners on the fracture resistance of denture base acrylic resin material. Impact strength, transverse strength, deflection, and elasticity modulus values of a heat-polymerized denture base resin (Trevalon),

G黮ay Uzun; Nur Hersek; Teoman Tin鏴r

1999-01-01

25

Analysis of Ninety Degree Flexure Tests for Characterization of Composite Transverse Tensile Strength  

NASA Technical Reports Server (NTRS)

Finite element (FE) analysis was performed on 3-point and 4-point bending test configurations of ninety degree oriented glass-epoxy and graphite-epoxy composite beams to identify deviations from beam theory predictions. Both linear and geometric non-linear analyses were performed using the ABAQUS finite element code. The 3-point and 4-point bending specimens were first modeled with two-dimensional elements. Three-dimensional finite element models were then performed for selected 4-point bending configurations to study the stress distribution across the width of the specimens and compare the results to the stresses computed from two-dimensional plane strain and plane stress analyses and the stresses from beam theory. Stresses for all configurations were analyzed at load levels corresponding to the measured transverse tensile strength of the material.

OBrien, T. Kevin; Krueger, Ronald

2001-01-01

26

Estimation of wall properties and wall strength of aortic aneurysms using modern imaging techniques. One more step towards a patient-specific assessment of aneurysm rupture risk.  

PubMed

Abdominal aortic aneurysmal disease is a major health problem with rupture representing its main complication accompanied by great mortality. Elective repair is currently performed with mortality rates <3%, based upon size or expansion rate, with a recommended threshold of 5.5 cm maximum diameter or >1cm/year enlargement. It is well established that even small AAAs without indication for surgical repair can experience rupture with catastrophic outcomes whereas larger aneurysms often remain intact for a long period. It is recognized, therefore, that the currently used, maximum diameter criterion can not accurately predict AAAs evolution. There is increasing interest in the role of patient-specific biomechanical profiling of AAA development and rupture. Biomechanically, rupture of a vessel occurs when intravascular forces exceed vessel wall structural endurance. Peak Wall Stress (PWS) has been previously shown to better identify AAAs prone to rupture than maximum diameter, but currently stress analysis takes into account several assumptions that influence results to a large extent and limit their use. Moreover stress represents only one of two determinants of rupture risk according to the biomechanical perspective. Wall strength and mechanical properties on the other hand cannot be assessed in vivo but only ex vivo through mechanical studies with mean values of these parameters taken into account for rupture risk estimations. New possibilities in the field of aortic imaging offer promising tools for the validation and advancement of stress analysis and the in vivo evaluation of AAAs' wall properties and wall strength. Documentation of aortic wall motion during cardiac cycle is now feasible through ECG-gated multi-detector CT imaging offering new possibilities towards an individualized method for rupture risk and expansion-rate predictions based on data acquired in vivo. PMID:23714223

Kontopodis, Nikolaos; Georgakarakos, Efstratios; Metaxa, Eleni; Pagonidis, Konstantinos; Papaharilaou, Yannis; Ioannou, Christos V

2013-08-01

27

Exciton states and oscillator strengths in a cylindrical quantum wire with finite potential under transverse electric field  

NASA Astrophysics Data System (ADS)

The effects of a transverse electric field on the electronic structure, exciton states, and oscillator strengths in a cylindrical quantum wire (QWR) are theoretically investigated. We consider a QWR made of GaAs material surrounded by a barrier of Al0.3Ga0.7As of finite depth potential. The electronic structure of the QWR, at the single electron level of theory, is obtained inside the effective mass approximation using the plane wave method, while the exciton states and transition oscillator strengths are calculated using the variational principle. The results show that the exciton oscillator strength is strongly enhanced due to the excitonic effect. The external electric field lifts the degeneracy of the electron or hole states. The energy levels of the electron and hole, exciton binding energy and exciton oscillator strength decrease with the increasing of the strength of the electric field. The stronger the electric field, the weaker the excitonic effect is. The influence of the electric field on exciton states and oscillator strengths becomes more significant for wide quantum wires. However, in sufficiently narrow wires, the influence of the electric field is also significant at small fields.

Wu, Shudong; Tomi?, Stanko

2012-08-01

28

Slow rupture and weakly pressure-sensitive strength enables compressional branching:1 Dynamic rupture simulations of the 2012 Off-Sumatra earthquake2  

E-print Network

rupture simulations of the 2012 Off-Sumatra earthquake2 3 Lingsen Meng* and Jean-Paul Ampuero4 5 Pasadena, CA 9112514 Phone: (626) 395-693115 Fax: (626) 564-071516 17 #12;Abstract:18 The 2012 M8.6 off-Sumatra and Oglesby, 2007]. The 2012 M8.6 off-Sumatra earthquake43 provides a rare example of large scale branching

Ampuero, Jean Paul

29

The eutectic carbides and creep rupture strength of 25Cr20Ni heat-resistant steel tubes centrifugally cast with different solidification conditions  

Microsoft Academic Search

The eutectic carbides and creep rupture strength of 25Cr20Ni heat-resistant steel tubes centrifugally cast with different solidification conditions were investigated in detail. The results reveal that the eutectic carbides precipitated primarily at the dendrite and grain boundaries show various morphologies from the outer wall to the inner wall along radial direction of the cast tubes, consisting of the thin film-like

X. Q Wu; H. M Jing; Y. G Zheng; Z. M Yao; W Ke; Z. Q Hu

2000-01-01

30

Strength Tests of Thin-walled Duralumin Cylinders in Combined Transverse Shear and Bending  

NASA Technical Reports Server (NTRS)

This report is the fourth of a series presenting the results of strength tests on thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results on 100 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. The tests show that as the ratio of moment to shear varies from small to large values the failure changes from a shear to a bending type. In the report a chart is presented that shows the corresponding changes in strength.

Lundquiest, Eugene E

1935-01-01

31

Effect of the fiber-matrix interphase on the transverse tensile strength of the unidirectional composite material  

NASA Technical Reports Server (NTRS)

A simple one-dimensional fiber-matrix interphase model has been developed and analytical results obtained correlated well with available experimental data. It was found that by including the interphase between the fiber and matrix in the model, much better local stress results were obtained than with the model without the interphase. A more sophisticated two-dimensional micromechanical model, which included the interphase properties was also developed. Both one-dimensional and two-dimensional models were used to study the effect of the interphase properties on the local stresses at the fiber, interphase and matrix. From this study, it was found that interphase modulus and thickness have significant influence on the transverse tensile strength and mode of failure in fiber reinforced composites.

Tsai, H. C.; Arocho, A. M.

1992-01-01

32

286 / JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING / MARCH 2000 shear strength before reinforcement rupture, which is not sup-  

E-print Network

after failure initiation is attributed to the loss of reinforcement tensile strength due to breakage) tensile strength because stability would be evaluated in this case using residual soil shear strength286 / JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING / MARCH 2000 shear strength before

Zornberg, Jorge G.

33

A fluid-structure interaction-based numerical investigation on the evolution of stress, strength and rupture potential of an abdominal aortic aneurysm.  

PubMed

An abdominal aortic aneurysm (AAA) is an irreversible dilation of the abdominal artery. Once an aneurysm is detected by doctors, clinical intervention is usually recommended. The interventions involve traditional open surgery repair and endovascular aneurysm repair with a stent graft. Both types of prophylactic procedures are expensive and not without any risk to the patient. It is very difficult to balance the risk of aneurysm repair and the chance of rupture. The reason lies in that the changing trend of characteristic physical quantities with the evolution of AAA and the mechanisms that give rise to it are still not completely clear. In this study, computational 3D patient-specific model for investigating AAA development was established based on computed tomography (CT) images. Results showed that as the aneurysm evolved, peak wall stress and time-averaged wall shear stress distribution patterns changed. The expansion of AAA wall resulted in the increment of peak stress. The AAA wall compliance not only showed different magnitudes at different cross-sections of the aneurismal body, but also changed with the development of the aneurysm. Furthermore, minimum wall strength and rupture potential index during the three stages of AAA evolution were also investigated in detail. This study might provide valuable information on how to further explore the mechanical basis and the rupture potential during AAA evolution, and that it may assist clinical diagnostic procedures and avoid the potential risk of unnecessary surgical intervention. PMID:22289116

Wang, Xiaohong; Li, Xiaoyang

2013-01-01

34

Biaxial normal strength behavior in the axial-transverse plane for human trabecular bone--effects of bone volume fraction, microarchitecture, and anisotropy.  

PubMed

The biaxial failure behavior of the human trabecular bone, which has potential relevance both for fall and gait loading conditions, is not well understood, particularly for low-density bone, which can display considerable mechanical anisotropy. Addressing this issue, we investigated the biaxial normal strength behavior and the underlying failure mechanisms for human trabecular bone displaying a wide range of bone volume fraction (0.06-0.34) and elastic anisotropy. Micro-computed tomography (CT)-based nonlinear finite element analysis was used to simulate biaxial failure in 15 specimens (5 mm cubes), spanning the complete biaxial normal stress failure space in the axial-transverse plane. The specimens, treated as approximately transversely isotropic, were loaded in the principal material orientation. We found that the biaxial stress yield surface was well characterized by the superposition of two ellipses--one each for yield failure in the longitudinal and transverse loading directions--and the size, shape, and orientation of which depended on bone volume fraction and elastic anisotropy. However, when normalized by the uniaxial tensile and compressive strengths in the longitudinal and transverse directions, all of which depended on bone volume fraction, microarchitecture, and mechanical anisotropy, the resulting normalized biaxial strength behavior was well described by a single pair of (longitudinal and transverse) ellipses, with little interspecimen variation. Taken together, these results indicate that the role of bone volume fraction, microarchitecture, and mechanical anisotropy is mostly accounted for in determining the uniaxial strength behavior and the effect of these parameters on the axial-transverse biaxial normal strength behavior per se is minor. PMID:24121715

Sanyal, Arnav; Keaveny, Tony M

2013-12-01

35

A Comparison of Creep Rupture Strength of Ferritic/Austenitic Dissimilar Weld Joints of Different Grades of Cr-Mo Ferritic Steels  

NASA Astrophysics Data System (ADS)

Evaluations of creep rupture properties of dissimilar weld joints of 2.25Cr-1Mo, 9Cr-1Mo, and 9Cr-1MoVNb steels with Alloy 800 at 823 K were carried out. The joints were fabricated by a fusion welding process employing an INCONEL 182 weld electrode. All the joints displayed lower creep rupture strength than their respective ferritic steel base metals, and the strength reduction was greater in the 2.25Cr-1Mo steel joint and less in the 9Cr-1Mo steel joint. Failure location in the joints was found to shift from the ferritic steel base metal to the intercritical region of the heat-affected zone (HAZ) of the ferritic steel (type IV cracking) with the decrease in stress. At still lower stresses, the failure in the joints occurred at the ferritic/austenitic weld interface. The stress-life variation of the joints showed two-slope behavior and the slope change coincided with the occurrence of ferritic/austenitic weld interface cracking. Preferential creep cavitation in the soft intercritical HAZ induced type IV failure, whereas creep cavitation at the interfacial particles induced ferritic/austenitic weld interface cracking. Micromechanisms of the type IV failure and the ferritic/austenitic interface cracking in the dissimilar weld joint of the ferritic steels and relative cracking susceptibility of the joints are discussed based on microstructural investigation, mechanical testing, and finite element analysis (FEA) of the stress state across the joint.

Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Goyal, Sunil; Mathew, M. D.

2012-04-01

36

The effect of joint surface contours and glass fiber reinforcement on the transverse strength of repaired acrylic resin: An in vitro study  

PubMed Central

Background: Denture fracture is an unresolved problem in complete denture prosthodontics. However, the repaired denture often experiences a refracture at the repaired site due to poor transverse strength. Hence, this study was conducted to evaluate the effect of joint surface contours and glass fiber reinforcement on the transverse strength of repaired acrylic resins. Materials and Methods: A total of 135 specimens of heat polymerized polymethyl methacrylate resin of dimensions 64 10 2.5 mm were fabricated. Fifteen intact specimens served as the control and 120 test specimens were divided into four groups (30 specimens each), depending upon the joint surface contour (butt, bevel, rabbet and round), with two subgroups based on type of the repair. Half of the specimens were repaired with plain repair resin and the other half with glass fibers reinforced repair resin. Transverse strength of the specimens was determined using three-point bending test. The results were analyzed using one-way ANOVA and Tukey post-hoc test (?= 0.05). Results: Transverse strength values for all repaired groups were significantly lower than those for the control group (P < 0.001) (88.77 MPa), with exception of round surface design repaired with glass fiber reinforced repair resin (89.92 MPa) which was significantly superior to the other joint surface contours (P < 0.001). Glass fiber reinforced resin significantly improved the repaired denture base resins as compared to the plain repair resin (P < 0.001). Conclusion: Specimens repaired with glass fiber reinforced resin and round surface design exhibited highest transverse strength; hence, it can be advocated for repair of denture base resins. PMID:23946739

Anasane, Nayana; Ahirrao, Yogesh; Chitnis, Deepa; Meshram, Suresh

2013-01-01

37

Numerical analysis of stress distribution in Cu-stabilized GdBCO CC tapes during anvil tests for the evaluation of transverse delamination strength  

NASA Astrophysics Data System (ADS)

Rare-earth-Ba-Cu-O (REBCO) based coated conductors (CCs) are now being used for electric device applications. For coil-based applications such as motors, generators and magnets, the CC tape needs to have robust mechanical strength along both the longitudinal and transverse directions. The CC tape in these coils is subjected to transverse tensile stresses during cool-down and operation, which results in delamination within and between constituent layers. In this study, in order to explain the behaviour observed in the evaluation of c-axis delamination strength in Cu-stabilized GdBCO CC tapes by anvil tests, numerical analysis of the mechanical stress distribution within the CC tape has been performed. The upper anvil size was varied in the analysis to understand the effect of anvil size on stress distribution within the multilayered CC tape, which is closely related to the delamination strength, delamination mode and delamination sites that were experimentally observed. The numerical simulation results showed that, when an anvil size covering the whole tape width was used, the REBCO coating film was subjected to the largest stress, which could result in low mechanical delamination and electromechanical delamination strengths. Meanwhile, when smaller-sized anvils were used, the copper stabilizer layer would experience the largest stress among all the constituent layers of the CC tape, which could result in higher mechanical and electromechanical delamination strengths, as well as high scattering of both of these delamination strengths. As a whole, the numerical simulation results could explain the damage evolution observed in CC tapes tested under transverse tensile stress, as well as the transverse tensile stress response of the critical current, Ic.

Dizon, John Ryan C.; Gorospe, Alking B.; Shin, Hyung-Seop

2014-05-01

38

Describing Soils: Calibration Tool for Teaching Soil Rupture Resistance  

ERIC Educational Resources Information Center

Rupture resistance is a measure of the strength of a soil to withstand an applied stress or resist deformation. In soil survey, during routine soil descriptions, rupture resistance is described for each horizon or layer in the soil profile. The lower portion of the rupture resistance classes are assigned based on rupture between thumb and

Seybold, C. A.; Harms, D. S.; Grossman, R. B.

2009-01-01

39

Monte Carlo characterization of skin doses in 6 MV transverse field MRI-linac systems: Effect of field size, surface orientation, magnetic field strength, and exit bolus  

SciTech Connect

Purpose: The main focus of this work is to continue investigations into the Monte Carlo predicted skin doses seen in MRI-guided radiotherapy. In particular, the authors aim to characterize the 70 {mu}m skin doses over a larger range of magnetic field strength and x-ray field size than in the current literature. The effect of surface orientation on both the entry and exit sides is also studied. Finally, the use of exit bolus is also investigated for minimizing the negative effects of the electron return effect (ERE) on the exit skin dose. Methods: High resolution GEANT4 Monte Carlo simulations of a water phantom exposed to a 6 MV x-ray beam (Varian 2100C) have been performed. Transverse magnetic fields of strengths between 0 and 3 T have been applied to a 30x30x20 cm{sup 3} phantom. This phantom is also altered to have variable entry and exit surfaces with respect to the beam central axis and they range from -75 deg. to +75 deg. The exit bolus simulated is a 1 cm thick (water equivalent) slab located on the beam exit side. Results: On the entry side, significant skin doses at the beam central axis are reported for large positive surface angles and strong magnetic fields. However, over the entry surface angle range of -30 deg. to -60 deg., the entry skin dose is comparable to or less than the zero magnetic field skin dose, regardless of magnetic field strength and field size. On the exit side, moderate to high central axis skin dose increases are expected except at large positive surface angles. For exit bolus of 1 cm thickness, the central axis exit skin dose becomes an almost consistent value regardless of magnetic field strength or exit surface angle. This is due to the almost complete absorption of the ERE electrons by the bolus. Conclusions: There is an ideal entry angle range of -30 deg. to -60 deg. where entry skin dose is comparable to or less than the zero magnetic field skin dose. Other than this, the entry skin dose increases are significant, especially at higher magnetic fields. On the exit side there is mostly moderate to high skin dose increases for 0.2-3 T with the only exception being large positive angles. Exit bolus of 1 cm thickness will have a significant impact on lowering such exit skin dose increases that occur as a result of the ERE.

Oborn, B. M.; Metcalfe, P. E.; Butson, M. J.; Rosenfeld, A. B. [Illawarra Cancer Care Centre (ICCC), Wollongong, New South Wales 2500 (Australia) and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales 2500 (Australia); Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales 2500 (Australia); Illawarra Cancer Care Centre (ICCC), Wollongong, New South Wales 2500 (Australia); Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales 2500 (Australia)

2010-10-15

40

High-frequency spectral falloff of earthquakes, fractal dimension of complex rupture, b value, and the scaling of strength on faults  

Microsoft Academic Search

The high-frequency falloff omega-gamma of earthquake displacement spectra and the b value of aftershock sequences are attributed to the character of spatially varying strength along fault zones. I assume that the high frequency energy of a main shock is produced by a self-similar distribution of subevents, where the number of subevents with radii greater than R is proportional to R-D,

Arthur Frankel

1991-01-01

41

Rupture of the uterus in a primigravida: a case report.  

PubMed

Uterine rupture during a first pregnancy is rare. We present the case of spontaneous intrapartum uterine rupture in a 40 year old primigravida with no prior uterine surgery, and a structurally normal uterus. The patient had obstructed labor. Operative findings were a male fresh stillbirth weighing 3800 g, massive hemoperitoneum, and an anterior transverse rupture at the lower uterine segment. Repair of the rupture was done without bilateral tubal ligation. Although a rare event, the primigravid uterus is not immune to rupture as exemplified by this report. PMID:20499765

Chigbu, B; Onwere, S; Kamanu, C; Aluka, C; Adibe, E; Onichakwe, C

2010-06-01

42

Surgical treatment of distal biceps rupture.  

PubMed

Rupture of the distal biceps tendon accounts for 10% of all biceps brachii ruptures. Injuries typically occur in the dominant elbow of men aged 40 to 49 years during eccentric contraction of the biceps. Degenerative changes, decreased vascularity, and tendon impingement may precede rupture. Although nonsurgical management is an option, healthy, active persons with distal biceps tendon ruptures benefit from early surgical repair, gaining improved strength in forearm supination and, to a lesser degree, elbow flexion. Biomechanical studies have tested the strength and displacement of various repairs; the suspensory cortical button technique exhibits maximum peak load to failure in vitro, and suture anchor and interosseous screw techniques yield the least displacement. Surgical complications include sensory and motor neurapraxia, infection, and heterotopic ossification. Current trends in postoperative rehabilitation include an early return to motion and to activities of daily living. PMID:20190104

Sutton, Karen M; Dodds, Seth D; Ahmad, Christopher S; Sethi, Paul M

2010-03-01

43

Transversity 2005  

NASA Astrophysics Data System (ADS)

Introduction. Purpose and status of the Italian Transversity Project / F. Bradamante -- Opening lecture. Transversity / M. Anselmino -- Experimental lectures. Azimuthal single-spin asymmetries from polarized and unpolarized hydrogen targets at HERMES / G. Schnell (for the HERMES Collaboration). Collins and Sivers asymmetries on the deuteron from COMPASS data / I. Horn (for the COMPASS Collaboration). First measurement of interference fragmentation on a transversely polarized hydrogen target / P. B. van der Nat (for the HERMES Collaboration). Two-hadron asymmetries at the COMPASS experiment / A. Mielech (for the COMPASS Collaboration). Measurements of chiral-odd fragmentation functions at Belle / R. Seidl ... [et al.]. Lambda asymmetries / A. Ferrero (for the COMPASS Collaboration). Transverse spin at PHENIX: results and prospects / C. Aidala (for the PHENIX Collaboration). Transverse spin and RHIC / L. Bland. Studies of transverse spin effects at JLab / H. Avakian ... [et al.] (for the CLAS Collaboration). Neutron transversity at Jefferson Lab / J. P. Chen ... [et al.] (for the Jefferson Lab Hall A Collaboration). PAX: polarized antiproton experiments / M. Contalbrigo. Single and double spin N-N interactions at GSI / M. Maggiora (for the ASSIA Collaboration). Spin filtering in storage rings / N. N. Nikolaev & F. F. Pavlov -- Theory lectures. Single-spin asymmetries and transversity in QCD / S. J. Brodsky. The relativistic hydrogen atom: a theoretical laboratory for structure functions / X. Artru & K. Benhizia. GPD's and SSA's / M. Burkardt. Time reversal odd distribution functions in chiral models / A. Drago. Soffer bound and transverse spin densities from lattice QCD / M. Diehl ... [et al.]. Single-spin asymmetries and Qiu-Sterman effect(s) / A. Bacchetta. Sivers function: SIDIS data, fits and predictions / M. Anselmino ... [et al.]. Twist-3 effects in semi-inclusive deep inelastic scattering / M. Schlegel, K. Goeke & A. Metz. Quark and gluon Sivers functions / I. Schmidt. Sivers effect in semi-inclusive deeply inelastic scattering and Drell-Yan / J. C. Collins ... [et al.]. Helicity formalism and spin asymmetries in hadronic processes / M. Anselmino ... [et al.]. Including Cahn and Sivers effects into event generators / A. Kotzinian. Comparing extractions of Sivers functions / M. Anselmino ... [et al.]. Anomalous Drell-Yan asymmetry from hadronic or QCD vacuum effects / D. Boer. "T-odd" effects in transverse spin and azimuthal asymmetries in SIDIS / L. P. Gamberg & G. R. Goldstein. T-odd effects in unpolarized Drell-Yan scattering / G. R. Goldstein & L. P. Gamberg. Alternative approaches to transversity: how convenient and feasible are they? / M. Radici. Relations between single and double transverse asymmetries / O. V. Teryaev. Cross sections, error bars and event distributions in simulated Drell-Yan azimuthal asymmetry measurements / A. Bianconi. Next-to-leading order QCD corrections for transversely polarized pp and p痯 collisions / A. Mukherjee, M. Stratmann & W. Vogelsang. Double transverse-spin asymmetries in Drell-Yan and J/[symbol] production from proton-antiproton collisions / M. Guzzi ... [et al.]. The quark-quark correlator: theory and phenomenology / E. Di Salvo. Chiral quark model spin filtering mechanism and hyperon polarization / S. M. Troshin & N. E. Tyurin -- Closing lecture. Where we've been ... and where we're going / G. Bunce.

Barone, Vincenzo; Ratcliffe, Philip G.

44

Spontaneous Kidney Allograft Rupture  

Microsoft Academic Search

Spontaneous renal allograft rupture is one of the most dangerous complications of kidney transplantation, which can result in graft loss.This condition needs immediate surgical intervention. Conservative management has dismal results. Its prevalence varies from 0.3% to 3%. Rupture occurs in first few weeks after transplantation. Predisposing factors for graft rupture are acute rejection, acute tubular necrosis, and renal vein thrombosis.

H. Shahrokh; H. Rasouli; M. A. Zargar; K. Karimi; K. Zargar

2005-01-01

45

Transversity 2008  

NASA Astrophysics Data System (ADS)

Purpose and status of the Italian transversity project / F. Bradamante -- Transversity asymmetries / D. Boer -- The transverse angular momentum sum rule / E. Leader -- Measurement of Collins and Sivers asymmetries at HERMES / L. L. Pappalardo (for the HERMES collaboration) -- Review of SSA results on deuteron at COMPASS / A. Richter (for the COMPASS collaboration) -- Single spin asymmetries on a transversely polarized proton target at COMPASS / S. Levorato (for the COMPASS collaboration) -- New preliminary results on the transversity distribution and the Collins fragmentation functions / M. Anselmino ... [et al.] -- Sivers effect in SIDIS pion and kaon production / M. Anselmino ... [et al.] -- Spin-orbit correlations / M. Burkardt -- Correlation functions in hard and (semi)-inclusive processes / M. Schlegel, S. Mei[symbol]ner and A. Metz -- Transversity via exclusive [pie symbol]-electroproduction / G. R. Goldstein, S. Liuti and S. Ahmad -- Estimate of the Sivers asymmetry at intermediate energies with rescattering extracted from exclusive processes / A. Bianconi -- Exclusively produced p[symbol] asymmetries on the deuteron and future GPD measurements at COMPASS / C. Schill (for the COMPASS collaboration) -- Transversity and transverse-momentum-dependent distribution measurements from PHENIX and BRAHMS / C. Aidala (for the PHENIX and BRAHMS collaborations) -- Sivers and Collins effects in polarized pp scattering processes / M. Anselmino ... [et al.] -- Sivers function in constituent quark models / S. Scopetta ... [et al.] -- Sivers, Boer-Mulders and transversity in Drell-Yan processes / M. Anselmino ... [et al.] -- TMDs and Drell-Yan experiments at Fermilab and J-PARC / J.-C. Peng -- Double polarisation observables at PAX / M. Nekipelov (for the PAX collaboration) -- Future Drell-Yan measurement @ COMPASS / M. Colantoni (for the COMPASS collaboration) -- Measurements of unpolarized azimuthal asymmetries at COMPASS / W. K鋐er (for the COMPASS collaboration) -- Measurement of azimuthal asymmetries of the unpolarized cross-section at HERMES / F. Giordano (for the HERMES collaboration) -- Measurement of transversity via an interference fragmentation function at HERMES / R. Fabbri (for the HERMES collaboration) -- Relating leading and higher twist contributions to nucleon spin structure / P. G. Ratcliffe and O. V. Teryaev -- DIS at low and high transverse momentum: matches and mismatches / A. Bacchetta ... [et al.] -- Pretzelosity distribution function h[symbol] / H. Avakian ... [et al.] -- Transverse momentum-spin correlations / L. P. Gamberg, G. R. Goldstein and M. Schlegel -- Exploring confinement with spin / J. P. Ralston -- SIDIS asymmetries in quark-diquark model / A. Kotzinian -- Parton densities in a spectator model with axial-vector diquarks / M. Radici -- Gluonic pole matrix elements in spectator models / A. Mukherjee, L. P. Gamberg and P. J. Mulders -- TMD measurements at CLAS6 and CLAS12 / H. Avakian (for the CLAS6 and CLAS12 collaborations) -- Nucleon to pion transition distribution amplitudes in a light-cone quark model / M. Pincetti, B. Pasquini and S. Boffi -- Antiproton polarization studies for FAIR (How to polarize antiprotons and what to use them for?) / H. Str鰄er, F. Rathmann and P. Lenisa -- No one can encompass the unencompassable: the highlights of transversity-2008 / N. N. Nikolaev.

Giuseppe, Ciullo; Paolo, Lenisa; Marco, Contalbrigo; Delia, Hasch

2009-04-01

46

[Transverse myelitis].  

PubMed

Transverse myelitis is a disease with various pathogenesis. It leads to a partial or total transverse lesion of the spinal cord structures resulting in an acute or subacute: motor (paralysis or paresis), sensory (most often with sensory level) and autonomic symptoms and signs. Its etiology is complex and sometimes difficult to establish explicitly. The most frequent reason of transverse myelitis is infection, but there are other factors like: postinfectious, neoplastic, paraneoplastic, demyelinating, immunological (connective tissue diseases), vascular and others. Idiopathic transverse myelitis accounts for about 10-40% of cases, and despite thorough diagnostics its aetiology cannot be established. Transeverse myelitis has been known for years, but it still poses a big problem both diagnostically and therapeuthically. Its course is frequently serious leading to persistent neurological damage and permanent disability. Diagnostic methods of choice are spinal cord MRI and CSF examination with assessment of oligoclonal bands, biomarkers of inflammatory process, 14-3-3 protein and neuronal specific enolase. Its treatment is determined by established aetiology. Many inconsistencies, no clear cut definition of the disease and lack of diagnostic criteria are being discussed by the group of experts working in Transverse Myelitis Consortium Group. PMID:22320033

Drozdowski, Wies?aw

2008-01-01

47

What Is an Earthquake?: Fault-Rupture Analogies  

NSDL National Science Digital Library

This activity has two parts: the first part will demonstrate the weaknesses of simple fault models (like block diagrams) in depicting the process of fault rupture accurately; and the second part is centered around a fairly simple animation of rupture propagation, seen by an oblique map view, that attempts to show more accurately what we should envision when we think about fault rupture. This activity provides different analogies for describing the process of fault rupture, with attention paid to the strengths and weaknesses of each.

48

Ruptured ulnar artery pseudoaneurysm  

Microsoft Academic Search

Ulnar artery aneurysms and pseudoaneurysms are rare lesions that usually occur distal to the wrist and cause symptoms as a result of embolization and not rupture. An elderly woman presented with acute rupture of an ulnar artery pseudoaneurysm proximal to the wrist, which caused severe neurologic compromise as a result of bleeding into Guyon's canal and the carpal tunnel. The

Luke S. Erdoes; William C. Brown

1995-01-01

49

Possible earthquake rupture speeds  

NASA Astrophysics Data System (ADS)

Though mode II shear fractures (primarily strike slip earthquakes) can not only exceed the shear wave speed of the medium, but can even reach the compressional wave speed, steady-state calculations showed that speeds between the Rayleigh and shear wave speeds were not possible, thus defining a forbidden zone. For more than 30 years it was believed that this result in which the rupture jumps over the forbidden zone, also holds for 3-D ruptures, in which mode II and mode III (mainly dip-slip faulting) are mixed. Using unprecedentedly fine spatial and temporal grids, we show that even in the simple configuration of homogeneous fault properties and linear slip-weakening friction law, a realistic 3-D rupture which start from rest and accelerates to some higher velocity, actually does pass smoothly through this forbidden zone, but very fast. The energy flux from the rupture tip is always positive, even within the so-called forbidden zone, contrary to the 2-D case. Finally, our results show that the width of the cohesive zone initially decreases, then increases as the rupture exceeds the shear wave speed and finally again decreases as the rupture accelerates to a speed of ~90% of the compressional wave speed. Several movies illustrating the development of the ruptures will be shown. A. Bizzari and S. Das (2012). Possible earthquake rupture speeds, EPSL, submitted.

Das, S.; Bizzarri, A.

2012-12-01

50

DEM Simulation of Direct Shear: 1. Rupture Under Constant Normal Stress Boundary Conditions  

NASA Astrophysics Data System (ADS)

A particle-based distinct element method and its grain-based method are used to generate and simulate a synthetic specimen calibrated to the rupture characteristics of an intact (non-jointed) low-porosity brittle rock deformed in direct shear. The simulations are compared to the laboratory-generated ruptures and used to investigate rupture at various normal stress magnitudes. The fracturing processes leading to shear rupture zone creation and the rupture mechanism are found to be normal stress dependent (progressing from tensile splitting to shear rupture) and show partial confirmation of rupture zone creation in nature and in experiments from other materials. The normal stress dependent change is found to be due to the orientation of the major principal stress and local stress concentrations internal to the synthetic specimens being deformed. The normal stress dependent rupture creation process results in a change to the rupture zone's geometry, shear stress versus horizontal displacement response, and thus ultimate strength.

Bewick, R. P.; Kaiser, P. K.; Bawden, W. F.; Bahrani, N.

2014-09-01

51

Shear rupture under constant normal stiffness boundary conditions  

NASA Astrophysics Data System (ADS)

A grain based Distinct Element Method and its embedded Grain Based Method are used to simulate the fracturing processes leading to shear rupture zone creation in a calibrated massive (non-jointed) brittle rock specimen deformed in direct shear under constant normal stiffness boundary conditions. Under these boundary conditions, shear rupture zone creation relative to the shear stress versus applied horizontal displacement (load-displacement) curve occurs pre-peak, before the maximum peak shear strength is reached. This is found to be the result of a normal stress feedback process caused by the imposed shear displacement which couples increases in normal stress, due to rupture zone dilation, with shear stress, producing a complex normal-shear stress-path that reaches and then follows the rock's yield (strength) envelope. While the yield envelope is followed, the shear strength increases further and shear stress oscillations (repeated stress drops followed by re-strengthening periods) in the load-displacement curves occur due to fracture creation as the rupture zone geometry smoothens. Once the maximum peak strength is reached (after a series of shear stress oscillations) the largest stress drops occur as the ultimate or residual shear strength is approached. The simulation results provide insight into the fracturing process during rupture zone creation and improve the understanding of the shear stress versus applied horizontal displacement response, as well as the stick-slip behaviour of shear rupture zones that are being created under constant normal stiffness boundary conditions.

Bewick, R. P.; Kaiser, P. K.; Bawden, W. F.

2014-11-01

52

Rupture velocity inferred from near-field differential ground motion  

NASA Astrophysics Data System (ADS)

The velocity of the rupture propagation is a fundamental source parameter that strongly affects ground motion. It is commonly assessed from kinematic inversion of strong-motion or teleseismic data, sometimes combined with InSar and/or GPS data. The obtained rupture velocity remains inevitably affected by uncertainties, mainly due to imperfect knowledge of the earth structure and tradeoffs between different source parameters. In this study we show how the analysis of differential ground-motion may help constraining the rupture velocity, without a priori information about the earth velocity structure. Our analysis is based on synthetic ground-motion simulations (0-2 Hz) for vertical strike-slip earthquakes propagating unilaterally at a fixed rupture velocity in a homogeneous elastic medium covered with a 1 km-thick low velocity layer (shear wave velocity equal to 1 km/s). We show that when the rupture reaches the bottom of the shallow layer, the phase velocity of transverse waves measured in the forward rupture direction up to a few rupture lengths is equal to the rupture velocity, for a large range of frequencies. The comparison with the phase velocity obtained for a point source then enables to retrieve the value of the rupture velocity. The phase velocity is simply computed from the ratio between the ground velocity and the shear strain or the rotation about a vertical axis. This study points out the utility of setting up dense arrays at the vicinity of major faults to retrieve rupture features such as the rupture velocity.

Causse, Mathieu; Cornou, C閏ile; B閏asse, Julie; Bouchon, Michel

2014-05-01

53

The impact of a single-layer or double-layer closure on uterine rupture  

Microsoft Academic Search

Objective: Our purpose was to measure the impact of a single-layer or double-layer closure on uterine rupture at subsequent delivery. Study Design: This is an observational cohort study of all women undergoing a trial of labor from 1988 to 2000 in a tertiary care center, after a single low transverse cesarean delivery. Factors most highly associated with uterine rupture were

Emmanuel Bujold; Camille Bujold; Emily F Hamilton; Fran鏾is Harel; Robert J Gauthier

2002-01-01

54

Creep rupture behavior of Stirling engine materials  

NASA Technical Reports Server (NTRS)

The automotive Stirling engine, being investigated jointly by the Department of Energy and NASA Lewis as an alternate to the internal combustion engine, uses high-pressure hydrogen as the working fluid. The long-term effects of hydrogen on the high temperature strength properties of materials is relatively unknown. This is especially true for the newly developed low-cost iron base alloy NASAUT 4G-A1. This iron-base alloy when tested in air has creep-rupture strengths in the directionally solidified condition comparable to the cobalt base alloy HS-31. The equiaxed (investment cast) NASAUT 4G-A1 has superior creep-rupture to the equiaxed iron-base alloy XF-818 both in air and 15 MPa hydrogen.

Titran, R. H.; Scheuerman, C. M.; Stephens, J. R.

1985-01-01

55

Uterine Rupture during Second Trimester Abortion with Misoprostol  

Microsoft Academic Search

Background: Data are limited regarding the use of misoprostol in the midtrimester, therefore few cases with uterine rupture during the second trimester with a previous uterine scar have been reported in the literature. Case Report: A 23-year-old woman with a prior low transverse cesarean section presented at 26 weeks gestation for pregnancy termination for a fetal abnormality. She was given

Umit Nayki; Cuneyt Eftal Taner; Tolga Mizrak; Cenk Nayki; Gulsen Derin

2005-01-01

56

Modeling rupture segmentations on the Cascadia megathrust  

NASA Astrophysics Data System (ADS)

The Cascadia subduction zone has produced a series of large to great earthquakes, most recently in 1700 AD. Paleoseismological studies of submarine turbidites suggest a significant difference in recurrence interval between Northern (~500 year) and Southern (~200-300 year) Cascadia. Whether future large ruptures are segmented is very important for estimating hazard in Pacific Northwest, but remains enigmatic from the interpretations of current locking maps. Our approach is to develop rupture scenarios of Cascadia earthquakes by performing numerical simulations using the finite element software, PyLith. Based on the USGS plate interface model of Cascadia, we have constructed a realistic three-dimensional subduction fault model that stretches from Northern California to Central Vancouver Island. We have performed a number of dynamic rupture simulations using a set of artificial friction parameters and uniform stress distributions on the fault governed by a slip-weakening friction law. Preliminary results show that ruptures have initiated from the nucleation zone with higher shear stress than the ambient fault and have propagated on the realistic three-dimensional fault surface. The increase of dip angle with depth has little effect on the rupture propagation because that is governed mostly by the fault strength. The along-strike bend of the fault beneath Washington state and Vancouver Island has not impeded the rupture propagation given the uniform fault strength. To estimate the possible rupture segmentation, we have converted a slip-deficit rate model derived from GPS data into stress change distributions on the fault assuming the entire slip deficit would be released in the next great earthquake. We are also constructing another initial stress map derived from tidal and leveling data, which shows a significant difference in the locking depth beneath Central Oregon. The other important variable, the spatial variation of frictional parameters, however, has to be determined under certain assumptions. We assume the critical distance, Dc, is proportional to the final slip, thus will be obtained from the slip deficit distribution. By combining the estimated stresses and Dc for the slip-weakening relation, we will investigate how the different interseismic locking profiles could influence possible segmentation for future ruptures on the Cascadia megathrust. This work is supported by FM Global.

Yang, H.; Liu, Y.; McGuire, J. J.

2012-12-01

57

Clinical recovery of two hip adductor longus ruptures: a case-report of a soccer player  

PubMed Central

Background Non-operative treatment of acute hip adductor longus ruptures in athletes has been described in the literature. However, very limited information concerning the recovery of this type of injury exists. This case represented a unique possibility to study the recovery of two acute adductor longus ruptures, using novel, reliable and validated assessment methods. Case presentation A 22-year old male soccer player (Caucasian) sustained two subsequent acute adductor longus ruptures, one in each leg. The injuries occurred 10爉onths apart, and were treated non-surgically in both situations. He was evaluated using hip-strength assessments, self-report and ultrasonography until complete muscle-strength recovery of the hip adductors had occurred. The player was able to participate in a full soccer training session without experiencing pain 15爓eeks after the first rupture, and 12爓eeks after the second rupture. Full hip adductor muscle-strength recovery was obtained 52爓eeks after the first rupture and 10爓eeks after the second rupture. The adductor longus injuries, as verified by initial ultrasonography (10燿ays post-injury), showed evidence of a complete tendon rupture in both cases, with an almost identical imaging appearance. It was only at 6 and 10爓eeks ultrasonographic follow-up that the first rupture was found to include a larger anatomical area than the second rupture. Conclusion From this case we can conclude that two apparently similar hip adductor longus ruptures, verified by initial ultrasonography (10燿ays post-injury), can have very different hip adductor strength recovery times. Assessment of adductor strength recovery may therefore in the future be a useful and important additional measure for determining when soccer players with hip adductor longus ruptures can return safely to play. PMID:23693119

2013-01-01

58

Imaging gate oxide ruptures  

Microsoft Academic Search

As minimum feature sizes are reduced in MOS silicon devices, dielectric breakdown continues to pose a formidable challenge. A more complete understanding of the failure mechanism which induces oxide rupture has become an absolute necessity in order to meet the advancing yield and reliability requirements of today's complex integrated structures. This paper will present an interesting insight into the nature

Horacio Mendez; Steve Morris; Sudhindra Tatti; Nicholas Dickson; Ronald E. Pyle

1993-01-01

59

Bipolar infrapatellar tendon rupture.  

PubMed

Traumatic patella alta in children occurs either distal to the patellar tendon as a tibial tubercle apophyseal fracture or proximally as an osteochondral sleeve fracture of the inferior patellar pole. Acute surgical exploration in a pediatric case of a knee extensor mechanism rupture revealed both proximal and distal (bipolar) patellar tendon pathology. PMID:7790483

Berg, E E

1995-01-01

60

Fault branching and rupture directivity  

Microsoft Academic Search

Could the directivity of a complex earthquake be inferred from the ruptured fault branches it created? Typically, branches develop in forward orientation, making acute angles relative to the propagation direction. Direct backward branching of the same style as the main rupture (e.g., both right lateral) is disallowed by the stress field at the rupture front. Here we propose another mechanism

Sonia Fliss; Harsha S. Bhat; Renata Dmowska; James R. Rice

2005-01-01

61

Iatrogenic tracheobronchial rupture  

PubMed Central

Abstract Iatrogenic tracheobronchial ruptures most frequently occur during tracheal intubation, but they can also be produced during tracheobronchial endoscopy or thoracic surgery. The clinical presentation can be brutal, with respiratory failure, cervical emphysema, pneumothorax and hemoptysis. There are also less symptomatic presentations. The diagnosis is confirmed by bronchoscopy. The therapeutic approach can be differentiated, surgical or conservative, although the criteria are not universally accepted. This article aims to review the indications and therapeutic options. PMID:25408752

Paraschiv, M

2014-01-01

62

Slow rupture of frictional interfaces  

NASA Astrophysics Data System (ADS)

The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not completely understood. We show that slow rupture is an intrinsic and robust property of simple non-monotonic rate-and-state friction laws. It is associated with a new velocity scale cmin, determined by the friction law, below which steady state rupture cannot propagate. We further show that rupture can occur in a continuum of states, spanning a wide range of velocities from cmin to elastic wave-speeds, and predict different properties for slow rupture and ordinary fast rupture. Our results are qualitatively consistent with recent high-resolution laboratory experiments and may provide a theoretical framework for understanding slow rupture phenomena along frictional interfaces.

Bar Sinai, Yohai; Brener, Efim A.; Bouchbinder, Eran

2012-02-01

63

Stress-rupture behavior of small diameter polycrystalline alumina fibers  

NASA Technical Reports Server (NTRS)

Continuous length polycrystalline alumina fibers are candidates as reinforcement in high temperature composite materials. Interest therefore exists in characterizing the thermomechanical behavior of these materials, obtaining possible insights into underlying mechanisms, and understanding fiber performance under long term use. Results are reported on the time-temperature dependent strength behavior of Nextel 610 and Fiber FP alumina fibers with grain sizes of 100 and 300 nm, respectively. Below 1000 C and 100 hours, Nextel 610 with the smaller grain size had a greater fast fracture and rupture strength than Fiber FP. The time exponents for stress-rupture of these fibers were found to decrease from approximately 13 at 900 C to below 3 near 1050 C, suggesting a transition from slow crack growth to creep rupture as the controlling fracture mechanism. For both fiber types, an effective activation energy of 690 kJ/mol was measured for rupture. This allowed stress-rupture predictions to be made for extended times at use temperatures below 1000 C.

Yun, Hee Mann; Goldsby, Jon C.; Dicarlo, James A.

1993-01-01

64

Rupture modes in laboratory earthquakes: Effect of fault prestress and nucleation conditions  

NASA Astrophysics Data System (ADS)

Seismic inversions show that earthquake risetimes may be much shorter than the overall rupture duration, indicating that earthquakes may propagate as self-healing, pulse-like ruptures. Several mechanisms for producing pulse-like ruptures have been proposed, including velocity-weakening friction, interaction of dynamic rupture with fault geometry and local heterogeneity, and effect of bimaterial contrast. We present experimental results on rupture mode selection in laboratory earthquakes occurring on frictional interfaces, which were prestressed both in compression and in shear. Our experiments demonstrate that pulse-like ruptures can exist in the absence of a bimaterial effect or of local heterogeneities. We find a systematic variation from crack-like to pulse-like rupture modes with both (1) decreasing nondimensional shear prestress and (2) decreasing absolute levels of shear and normal prestress for the same value of nondimensional shear prestress. Both pulse-like and crack-like ruptures can propagate with either sub-Rayleigh or supershear rupture speeds. Our experimental results are consistent with theories of ruptures on velocity-weakening interfaces, implying that velocity-weakening friction plays an important role in governing the dynamic behavior of earthquake ruptures. We show that there is no measurable fault-normal stress decrease on the fault plane due to the nucleation procedure employed in experiments, and hence, this is not a factor in the rupture mode selection. We find that pulse-like ruptures correspond to the levels of nondimensional shear prestress significantly lower than the static friction coefficient, suggesting that faults hosting pulse-like ruptures may operate at low levels of prestress compared to their static strength.

Lu, Xiao; Rosakis, Ares J.; Lapusta, Nadia

2010-12-01

65

Compressive strength of carbon fibers  

SciTech Connect

Direct transverse compressive test of pitch-based carbon fibers was carried out on the single filament. The carbon fibers had randomly or radially orientation textures of graphite crystallite in the cross section. Both the transverse modulus and transverse compressive strength decreased with crystallite size increasing. There is little influence of orientation texture in cross section on the transverse modulus and transverse compressive strength. Fracture behavior was also observed under a scanning electron microscope from two directions. The fracture part was limited near the contact area of the punch for randomly oriented fibers, but the fracture of radially oriented fibers tend to be extended along the fiber axis. Fragment of fractured fiber with small crystallite was smaller. The fracture path in the cross section was run through the center of cross section and the edge of contact area with punch.

Sawada, Yoshihiro; Fujita, Kazuhiro; Nakanishi, Yoichiro [Government Industrial Research Institute, Osaka (Japan)

1993-12-31

66

Uterine rupture: Preventable obstetric tragedies?  

Microsoft Academic Search

Background: Although ruptured uterus is nowadays a rare obstetric emergency in Western countries, it is still alarmingly common in developing countries, where it remains a major cause of maternal mortality and morbidity. Aims: To review the recent experience of uterine rupture at a tertiary obstetric unit in eastern Nepal and to recommend improvements in the current management of labour, especially

Sangeeta K. MISHRA; Norman MORRIS; Dhruba Kumar UPRETY

2006-01-01

67

Spontaneous rupture of the oesophagus  

Microsoft Academic Search

Background: The aim of this study was to evaluate the diagnosis, management and outcome of patients with spontaneous rupture of the oesophagus in a single centre. Methods: Between October 1993 and May 2007, 51 consecutive patients with spontaneous oesophageal rupture were evaluated with contrast radiology and flexible endoscopy. Patients with limited contamination who fulfilled specific criteria were managed by a

S. M. Griffin; P. J. Lamb; J. Shenfine; D. L. Richardson; D. Karat; N. Hayes

2008-01-01

68

Long-term creep-rupture failure envelope of epoxy  

NASA Astrophysics Data System (ADS)

An accelerated testing methodology based on the time-temperature superposition principle has been proposed in the literature for the long-term creep strength of polymer matrices and polymer composites. Also, it has been suggested that a standard master curve may be a feasible assumption to describe the creep behavior in both tension and compression modes. In the present research, strength master curves for an aerospace epoxy (8552) were generated for tension and compression, by shifting strength data measured at various temperatures. The shift function is obtained from superposition of creep-compliance curves obtained at different temperatures. A standard master curve was presented to describe the creep-rupture of the polymer under tension and compression. Moreover, long-term creep-rupture failure envelopes of the polymer were presented based on a two-part failure criterion for homogeneous and isotropic materials. Ultimately, the approach presented allows the prediction of creep-rupture failure envelopes for a time-dependent material based on tensile strengths measured at various temperatures, considering that the ratio between tensile and compressive strengths is known.

Melo, Jos Daniel D.; de Medeiros, Antonio M.

2014-02-01

69

Transversity Measurements at COMPASS  

E-print Network

The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. From the analysis of the 2002-2004 data, new results for the transverse target spin asymmetry of z-ordered identified pion and kaon pairs are presented. In addition, a first result for the transverse target spin asymmetry of exclusively produced rho^0 mesons on the deuteron is shown.

COMPASS Collaboration; C. Schill

2007-09-28

70

Shallow dynamic overshoot and energetic deep rupture in the 2011 Mw 9.0 Tohoku-Oki earthquake.  

PubMed

Strong spatial variation of rupture characteristics in the moment magnitude (M(w)) 9.0 Tohoku-Oki megathrust earthquake controlled both the strength of shaking and the size of the tsunami that followed. Finite-source imaging reveals that the rupture consisted of a small initial phase, deep rupture for up to 40 seconds, extensive shallow rupture at 60 to 70 seconds, and continuing deep rupture lasting more than 100 seconds. A combination of a shallow dipping fault and a compliant hanging wall may have enabled large shallow slip near the trench. Normal faulting aftershocks in the area of high slip suggest dynamic overshoot on the fault. Despite prodigious total slip, shallower parts of the rupture weakly radiated at high frequencies, whereas deeper parts of the rupture radiated strongly at high frequencies. PMID:21596957

Ide, Satoshi; Baltay, Annemarie; Beroza, Gregory C

2011-06-17

71

Shallow Dynamic Overshoot and Energetic Deep Rupture in the 2011 Mw 9.0 Tohoku-Oki Earthquake  

NASA Astrophysics Data System (ADS)

Strong spatial variation of rupture characteristics in the moment magnitude (Mw) 9.0 Tohoku-Oki megathrust earthquake controlled both the strength of shaking and the size of the tsunami that followed. Finite-source imaging reveals that the rupture consisted of a small initial phase, deep rupture for up to 40 seconds, extensive shallow rupture at 60 to 70 seconds, and continuing deep rupture lasting more than 100 seconds. A combination of a shallow dipping fault and a compliant hanging wall may have enabled large shallow slip near the trench. Normal faulting aftershocks in the area of high slip suggest dynamic overshoot on the fault. Despite prodigious total slip, shallower parts of the rupture weakly radiated at high frequencies, whereas deeper parts of the rupture radiated strongly at high frequencies.

Ide, Satoshi; Baltay, Annemarie; Beroza, Gregory C.

2011-06-01

72

Spontaneous rupture of adrenal haemangioma mimicking abdominal aortic aneurysm rupture  

PubMed Central

Serious bleeding from a ruptured adrenal mass limits preoperative diagnostics and can necessitate urgent laparotomy to control blood loss. A 45-year old man underwent an emergency laparotomy due to severe retroperitoneal haemorrhage causing hypovolaemia. Detailed retroperitoneal dissection after splenectomy and clamping of the abdominal aorta revealed bleeding from a ruptured haemangioma of the left adrenal gland. Following a left adrenalectomy, the patient returned to a stable haemodynamic state. Adrenal haemangiomas are rare, but may cause spontaneous life-threatening haemorrhage. PMID:22371732

Ambroziak, Iwona; Holynska-Dabrowska, Katarzyna; Siezieniewska-Skowronska, Zofia; Paluszkiewicz, Andrzej

2010-01-01

73

TRANSVERSELY POLARIZED L PRODUCTION.  

SciTech Connect

Transversely polarized {Lambda} production in hard scattering processes is discussed in terms of a leading twist T-odd fragmentation function which describes the fragmentation of an unpolarized quark into a transversely polarized {Lambda}. We focus on the properties of this function and its relevance for the RHIC and HERMES experiments.

BORER,D.

2000-05-22

74

TRANSVERSITY SINGLE SPIN ASYMMETRIES.  

SciTech Connect

The theoretical aspects of two leading twist transversity single spin asymmetries, one arising from the Collins effect and one from the interference fragmentation functions, are reviewed. Issues of factorization, evolution and Sudakov factors for the relevant observables are discussed. These theoretical considerations pinpoint the most realistic scenarios towards measurements of transversity.

BOER,D.

2001-04-27

75

Imaging gate oxide ruptures  

NASA Astrophysics Data System (ADS)

As minimum feature sizes are reduced in MOS silicon devices, dielectric breakdown continues to pose a formidable challenge. A more complete understanding of the failure mechanism which induces oxide rupture has become an absolute necessity in order to meet the advancing yield and reliability requirements of today's complex integrated structures. This paper will present an interesting insight into the nature of dielectric breakdown in MOS transistors produced from a novel cross-sectioning TEM sample preparation method using a focused ion beam tool. By using deductive failure analysis, it was possible to determine the location of the leakage within a 1000 angstroms portion of the transfer gate of a one megabit DRAM. Once localized, a creative combination of conventional glass lapping and focused ion beam techniques were used to produce the thin TEM slice which contained the oxide breakdown. An image of the breakdown was then obtained on a 200 keV TEM. Interestingly, the image revealed that the origin of the breakdown was associated with imperfections in the form of voids in the surface of the silicon substrate. These results proved to be consistent over multiple samples. In this paper a complete description of these images will be presented along with possible theories describing the fundamental origin of these defects.

Mendez, Horacio; Morris, Steve; Tatti, Sudhindra; Dickson, Nicholas; Pyle, Ronald E.

1993-01-01

76

Steam generator tube rupture study  

E-print Network

This report describes our investigation of steam generator behavior during a postulated tube rupture accident. Our study was performed using the steam generator, thermal-hydraulic analysis code THERMIT-UTSG. The purpose ...

Free, Scott Thomas

1986-01-01

77

Partial ACL rupture: an MR diagnosis?  

Microsoft Academic Search

Purpose. We sought to clarify the ability of magnetic resonance imaging (MR) to show partial ante- rior cruciate ligament (ACL) ruptures and to allow dis- tinction of partial from complete ACL ruptures. Materials and methods. Eighty-eight patients were stud- ied by arthroscopy and MR (36 with normal ACLs, 21 with partial ACL ruptures, and 31 with complete ACL ruptures). MR

Lawrence Yao; Amilcare Gentili; Leonard Petrus; Joong K. Lee

1995-01-01

78

Some characteristics of high strength fiber reinforced lightweight aggregate concrete  

Microsoft Academic Search

The effect of polypropylene and steel fibers on high strength lightweight aggregate concrete is investigated. Sintered fly ash aggregates were used in the lightweight concrete; the fines were partially replaced by fly ash. The effects on compressive strength, indirect tensile strength, modulus of rupture, modulus of elasticity, stress杝train relationship and compression toughness are reported. Compared to plain sintered fly ash

O Kayali; M. N Haque; B Zhu

2003-01-01

79

Alliance ruptures and rupture resolution in cognitive朾ehavior therapy: A preliminary task analysis  

Microsoft Academic Search

An initial ideal, rational model of alliance rupture and rupture resolution provided by cognitive朾ehavioral therapy (CBT) experts was assessed and compared with empirical observations of ruptures and their resolution in two cases of successful CBT. The initial rational model emphasized nondefensive acknowledgment and exploration of the rupture. Results indicated differences between what therapists think they should do to resolve ruptures

Helen Aspland; Susan Llewelyn; Gillian E. Hardy; Michael Barkham; William Stiles

2008-01-01

80

Complex rupture during the 12 January 2010 Haiti earthquake  

USGS Publications Warehouse

Initially, the devastating Mw 7.0, 12 January 2010 Haiti earthquake seemed to involve straightforward accommodation of oblique relative motion between the Caribbean and North American plates along the Enriquillog-Plantain Garden fault zone. Here, we combine seismological observations, geologic field data and space geodetic measurements to show that, instead, the rupture process may have involved slip on multiple faults. Primary surface deformation was driven by rupture on blind thrust faults with only minor, deep, lateral slip along or near the main Enriquillog-Plantain Garden fault zone; thus the event only partially relieved centuries of accumulated left-lateral strain on a small part of the plate-boundary system. Together with the predominance of shallow off-fault thrusting, the lack of surface deformation implies that remaining shallow shear strain will be released in future surface-rupturing earthquakes on the Enriquillog-Plantain Garden fault zone, as occurred in inferred Holocene and probable historic events. We suggest that the geological signature of this earthquakeg-broad warping and coastal deformation rather than surface rupture along the main fault zoneg-will not be easily recognized by standard palaeoseismic studies. We conclude that similarly complex earthquakes in tectonic environments that accommodate both translation and convergenceg-such as the San Andreas fault through the Transverse Ranges of Californiag-may be missing from the prehistoric earthquake record. ?? 2010 Macmillan Publishers Limited. All rights reserved.

Hayes, G. P.; Briggs, R. W.; Sladen, A.; Fielding, E. J.; Prentice, C.; Hudnut, K.; Mann, P.; Taylor, F. W.; Crone, A. J.; Gold, R.; Ito, T.; Simons, M.

2010-01-01

81

Transversity signals at COMPASS  

E-print Network

COMPASS is a fixed target experiment at the CERN SPS, with a rich physics program focused on nucleon spin structure and on hadron spectroscopy. One of the main goals of the spin program is the measurement of the transverse spin distribution function $\\Delta_T q(x)$ in semi-inclusive DIS off transversely polarized nucleons. For this purpose approximately 20% of the running time in the years 2002 to 2004 with the longitudinally polarized muon beam of 160 GeV and with $^6$LiD polarized target was used to collect data with the target polarized transversely with respect to the beam direction. The 2002 data have been already analysed and published. We present here the preliminary results from the full statistics for the Collins and Sivers single hadron asymmetries and for the transverse spin asymmetry in hadron pair production.

By COMPASS Collaboration

2007-12-19

82

Coupling a geodynamic seismic cycling model to rupture dynamic simulations  

NASA Astrophysics Data System (ADS)

The relevance and results of dynamic rupture scenarios are implicitly linked to the geometry and pre-existing stress and strength state on a fault. The absolute stresses stored along faults during interseismic periods, are largely unquantifiable. They are, however, pivotal in defining coseismic rupture styles, near-field ground motion, and macroscopic source properties (Gabriel et al., 2012). Obtaining these in a physically consistent manner requires seismic cycling models, which directly couple long-term deformation processes (over 1000 year periods), the self-consistent development of faults, and the resulting dynamic ruptures. One promising approach to study seismic cycling enables both the generation of spontaneous fault geometries and the development of thermo-mechanically consistent fault stresses. This seismo-thermo-mechanical model has been developed using a methodology similar to that employed to study long-term lithospheric deformation (van Dinther et al., 2013a,b, using I2ELVIS of Gerya and Yuen, 2007). We will innovatively include the absolute stress and strength values along physically consistent evolving non-finite fault zones (regions of strain accumulation) from the geodynamic model into dynamic rupture simulations as an initial condition. The dynamic rupture simulations will be performed using SeisSol, an arbitrary high-order derivative Discontinuous Galerkin (ADER-DG) scheme (Pelties et al., 2012). The dynamic rupture models are able to incorporate the large degree of fault geometry complexity arising in naturally evolving geodynamic models. We focus on subduction zone settings with and without a splay fault. Due to the novelty of the coupling, we first focus on methodological challenges, e.g. the synchronization of both methods regarding the nucleation of events, the localization of fault planes, and the incorporation of similar frictional constitutive relations. We then study the importance of physically consistent fault stress, strength, and geometry input for dynamic rupture propagation in terms of rupture path and dynamics. On the other hand, it will provide the opportunity to compare slow earthquake akin events developing in quasi-static geodynamic model to fully dynamic ruptures in terms of coseismic displacements and stress changes. Gabriel, A.-A. (2012), J.-P. Ampuero, L. A. Dalguer, and P. M. Mai, The transition of dynamic rupture modes in elastic media, J. Geophys. Res., 117(B9), 01480227. Gerya, T., and D. Yuen (2007), Robust characteristics method for modelling multiphase visco-elasto-plastic thermo-mechanical problems, Phys. Earth Planet In., 163(1-4), 83-105. Pelties, C. (2012), J. De la Puente, J.-P. Ampuero, G. B. Brietzke, and M. K鋝er Three-Dimensional Dynamic Rupture, Simulation with a High-order Discontinuous Galerkin Method on Unstructured Tetrahedral Meshes, J. Geophys. Res., 117(B2), B02309. van Dinther, Y. (2013a), T.V. Gerya, L.A. Dalguer, F. Corbi, F. Funiciello, and P.M. Mai, The seismic cycle at subduction thrusts: 2. Dynamic implications of geodynamic simulations validated with laboratory models, J. Geophys. Res., 118(4), 1502-1525. van Dinther, Y. (2013b), T.V. Gerya, L.A. Dalguer, P.M. Mai, G. Morra, and D. Giardini, The seismic cycle at subduction thrusts: insights from seismo-thermo-mechanical models, J. Geophys. Res., 118, 6183-6202.

Gabriel, Alice; van Dinther, Ylona

2014-05-01

83

Structural integrity evaluation method for overheating rupture of FBR steam generator tube  

Microsoft Academic Search

This paper describes a structural integrity evaluation method for a SG tube of FBR in case of sodium杦ater reaction and creep rupture tests to obtain the strength of the tube material. In the SG of FBR, if intermediate size of water\\/steam leak (12 kg s?1) would occur from a tube, it could cause overheating rupture of the multiple tubes surrounding

Hideo Machida; Naoki Yoshioka; Hideyasu Ogo

2002-01-01

84

Elbow tendinopathy and tendon ruptures: epicondylitis, biceps and triceps ruptures.  

PubMed

Lateral and medial epicondylitis are common causes of elbow pain in the general population, with the lateral variety being more common than the medial by a ratio reportedly ranging from 4:1 to 7:1. Initially thought to be an inflammatory condition, epicondylitis has ultimately been shown to result from tendinous microtearing followed by an incomplete reparative response. Numerous nonoperative and operative treatment options have been employed in the treatment of epicondylitis, without the emergence of a single, consistent, universally accepted treatment protocol. Tendon ruptures about the elbow are much less frequent, but result in more significant disability and loss of function. Distal biceps tendon ruptures typically occur in middle-aged males as a result of an event that causes a sudden, eccentric contraction of the biceps. Triceps tendon ruptures are exceedingly rare but usually have a similar etiology with a forceful eccentric contraction of the triceps that causes avulsion of the tendon from the olecranon. The diagnosis of these injuries is not always readily made. Complete ruptures of the biceps or triceps tendons have traditionally been treated surgically with good results. With regard to biceps ruptures, there continues to be debate about the best surgical approach, as well as the best method of fixation of tendon to bone. This article is not meant to be an exhaustive review of the broad topics of elbow tendinopathy and tendon ruptures, but rather is a review of recently published information on the topics that will assist the clinician in diagnosis and management of these conditions. PMID:19258160

Rineer, Craig A; Ruch, David S

2009-03-01

85

Effect of Electron Beam Irradiation on Tensile Strength of Polypropylene  

NASA Astrophysics Data System (ADS)

In this paper, the effects of the intensity of electron beam and the variation with time after irradiation of electron beam on the tensile strength of the polypropylene (PP), which is widely used as medicine containers, were investigated. PP with and without colorants were used first and samples irradiated under various intensity of EB. A tensile test on the irradiated samples with elapsed time after the irradiation of the electron beam was carried out. The effects of those factors on the tensile strength were discussed. The following results were obtained (1) The tensile strength of PP decreased due to the influence of the electron beam irradiation, however the rate of the decrease in strength was small compared with the original one. Furthermore, the rate of the decrease in strength was very small owing to the variation with time after the EB irradiation. (2) The tensile rupture strength of PP increased and the rupture strain owing to the influence of the electron beam irradiation compared with the original one. In addition, these rupture strength increased and the rupture strain decreased along with time after the irradiation of the electron beam. (3) The tensile rupture strain energy of PP decreased owing to the influence of the electron beam irradiation compared with the original one. In addition, the strain energy decreases with time after the irradiation of the electron beam. Moreover, the strength characteristics of PP with colorants received greater influence of electron beam compared with the one without colorants.

Yamada, Hiroshi; Ikeda, Masayuki; Shimbo, Minoru; Miyano, Yasushi

86

Rupture of the flexor digitorum superficialis muscle belly during isometric weight training.  

PubMed

Isometric weight training is a well-recognised technique used by fitness trainers to increase muscle strength. We report a case of a flexor digitorum superficialis muscle belly rupture that occurred during this form of muscle training. Rupture of the belly of the forearm flexor muscles is rare. When the muscle undergoes tractional force in isometric weight training, there is a potential for it to rupture and result in the formation of a haematoma. This can lead to raised intracompartmental pressures which would require treatment with urgent fasciotomy. An awareness of this potential injury mechanism will help with early recognition and appropriate treatment. PMID:24177460

Chow, Whitney; Dickson, John; Khan, Umraz

2013-01-01

87

Cervical ruptures in midtrimester abortions.  

PubMed

2 groups of patients are at risk of traumatic complication after midtrimester abortion: older multiparous women (uterine ruptures) and young primigravid women (cervical ruptures). While the occurrence of uterine ruptures in the former class can be reduced by selective use of abortifacient agents, and avoidance of amnioinfusions and intravenous oxytocin, the occurrence of cervical ruptures continues to be high. From May 1974 through May 1978, 780 women underwent midtrimester abortion by various techniques. 12 patients (1.5%) sustained cervical injuries, 11 of whom were nulliparous aged 16 to 25 years. Intra-amniotic and extra-ovular methods alike produced cervical injuries. The combined method of induction increases the likelihood of damaging the cervix. Oxytocic augmentation, however, does not appear to increase its incidence. Nor does a shorter induction-abortion interval, according to the evidence. Since laminaria tents did not prevent cervical injuries, none of the presently available methods offers any protection. Nevertheless, it may be that cervical injuries can be prevented if midtrimester abortions are undertaken between 13 and 15 weeks of pregnancy. Cervical ruptures can also go unnoticed and cause future obstetric problems; the authors therefore emphasize the importance of routine cervical inspection in all patients. PMID:12335921

Rajan, R; Usha, K R

1979-06-01

88

Delayed diaphragmatic rupture presenting with acute gastric volvulus.  

PubMed

Gastric volvulus is a rare complication of diaphragmatic rupture. We report the case of an 82-year-old man who presented following an out-of-hospital cardiac arrest. Chest radiography and thoracic computed tomography revealed an acute gastric volvulus and a chronic diaphragmatic hernia containing transverse colon and abdominal viscera. He had complained of retching and associated epigastric pain prior to collapse, and had sustained a motorcycle accident approximately 60 years earlier. Insertion of a nasogastric tube was unsuccessful (completing Borchardt's diagnostic triad) and his condition prevented both operative and endoscopic reduction of his volvulus. He died soon afterwards. PMID:25245717

Williamson, Jml; Macleod, R; Hollowood, A

2014-10-01

89

MRI in transverse myelitis.  

PubMed

Transverse myelitis is an acute inflammatory disease of the spinal cord, characterized by rapid onset of bilateral neurological symptoms. Weakness, sensory disturbance, and autonomic dysfunction evolve over hours or days, most progressing to maximal clinical severity within 10 days of onset. At maximal clinical severity, half will have a paraparesis, and almost all patients have sensory disturbance and bladder dysfunction. Residual disability is divided equally between severe, moderate and minimal or none. The causes of transverse myelitis are diverse; etiologies implicated include demyelinating conditions, collagen vascular disease, and parainfectious causes, however, despite extensive diagnostic work-up many cases are considered idiopathic. Due to heterogeneity in pathogenesis, and the similarity of its clinical presentation with those of various noninflammatory myelopathies, transverse myelitis has frequently been viewed as a diagnostic dilemma. However, as targeted therapies to optimize patient outcome develop, timely identification of the underlying etiology is becoming increasingly important. In this review, we describe the imaging and clinical features of idiopathic and disease-associated transverse myelitis and its major differentials, with discussion of how MR imaging features assist in the identification of various sub-types of transverse myelitis. We will also discuss the potential for advanced MR techniques to contribute to diagnosis and prognostication. J. Magn. Reson. Imaging 2014;40:1267-1279. 2014 Wiley Periodicals, Inc. PMID:24752988

Goh, Christine; Desmond, Patricia M; Phal, Pramit M

2014-12-01

90

Ruptures of the rotator cuff.  

PubMed Central

Through the use of improved diagnostic techniques, including arthrography and arthroscopy, ruptures of the rotator cuff that previously might not have been recognized are now being identified more frequently. In most cases the symptoms are relatively mild and respond satisfactorily to rest and therapy. Occasionally, however, there is severe, persistent disability despite treatment. These ruptures require surgical repair. In such cases the data obtained from special investigations help the surgeon select the appropriate surgical approach and repair technique. An imaginative program of physiotherapy before and after the operation contributes greatly to a satisfactory result. Images FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 7 PMID:7437980

Ha'eri, G B

1980-01-01

91

Self-Rupturing Hermetic Valve  

NASA Technical Reports Server (NTRS)

For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self-energizing and requires low force compared to current pyrotechnic-based burst disk hermetic valves. This is a novel design for producing a single-use, self-rupturing, hermetically sealed valve for isolation of pressurized gas and/or liquids. This design can also be applied for single-use disposable valves for chemical instruments. A welded foil diaphragm is fully supported by two mated surfaces that are machined to micron accuracies using EDM. To open the valve, one of the surfaces is moved relative to the other to (a) remove the support creating an unsupported diaphragm that ruptures due to over pressure, and/or (b) produce tension in the diaphragm and rupture it.

Tucker, Curtis E., Jr.; Sherrit, Stewart

2011-01-01

92

Deconstructed Transverse Mass Variables  

E-print Network

Traditional searches for R-parity conserving natural supersymmetry (SUSY) require large transverse mass and missing energy cuts to separate the signal from large backgrounds. SUSY models with compressed spectra inherently produce signal events with small amounts of missing energy that are hard to explore. We use this difficulty to motivate the construction of "deconstructed" transverse mass variables which are designed preserve information on both the norm and direction of the missing momentum. We demonstrate the effectiveness of these variables in searches for the pair production of supersymmetric top-quark partners which subsequently decay into a final state with an isolated lepton, jets and missing energy. We show that the use of deconstructed transverse mass variables extends the accessible compressed spectra parameter space beyond the region probed by traditional methods. The parameter space can further be expanded to neutralino masses that are larger than the difference between the stop and top masses. ...

Ismail, Ahmed; Virzi, Joseph S; Walker, Devin G E

2014-01-01

93

Transverse colon conduit diversion  

SciTech Connect

The versatility and other advantages of the transverse colon conduit for urinary diversion have been described and implemented in 50 patients. Because most patients considered for this procedure will be at high risk because of a history of significant pelvic irradiation, underlying malignancy, poor renal function, fistula, and so forth, the technical details of surgery and patient selection cannot be minimized. The transverse colon segment is indicated for primary supravesical diversion as well as for salvage of problems related to ileal conduits. Adenocarcinoma of the colon is an unlikely long-term complication of this form of diversion because the fecal stream is absent. Now that the transverse colon conduit has been used for more than 10 years, meaningful comparisons with ileal segments should soon be available.

Schmidt, J.D.; Buchsbaum, H.J.

1986-05-01

94

Nondiffracting transversally polarized beam.  

PubMed

Generation of a nondiffracting transversally polarized beam by means of transmitting an azimuthally polarized beam through a multibelt spiral phase hologram and then highly focusing by a high-NA lens is presented. A relatively long depth of focus (?4.84?) of the electric field with only radial and azimuthal components is achieved. The polarization of the wavefront near the focal plane is analyzed in detail by calculating the Stokes polarization parameters. It is found that the polarization is spatially varying and entirely transversally polarized, and the polarization singularity disappears at the beam center, which makes the central bright channel possible. PMID:21886250

Yuan, G H; Wei, S B; Yuan, X-C

2011-09-01

95

Transverse freezing of thin liquid films  

NASA Astrophysics Data System (ADS)

A pair of coupled non-linear partial differential equations is derived using lubrication theory that govern the morphology of a thin, liquid film of a pure and a binary metal alloy, bounded by the liquid's solid phase and a passive gas phase. The analysis is motivated by the directional freezing of metallic foams, and is a first attempt to model transverse freezing in thin films that form in foam networks, but also applies to thin film layers in general. Both the no-slip crystal-melt and the free melt-gas interfaces are deformable. The governing pair of non-linear differential equations for the most general case incorporate crystal-melt and melt-gas surface tension, latent heat, heat transfer, volume change, molecular interactions, thermocapillary and dilute phase concentration effects. Linear analysis of a uniform film reveals a variety of instabilities. A unique wavenumber is selected at the onset of instability in the case of an applied temperature gradient with vanishing crystal-melt surface tension. This system reproduces the isothermal result for a rigid solid-liquid interface in which a band of wavenumbers is unstable. A new long-wave instability has been identified, for the case with CM surface tension, that is due to the coupling of the interfaces. Numerical solutions of the fully non-linear system provide film evolution and rupture times, and show that, near the critical conditions, rupture can occur by the growth of standing or traveling waves. The numerics also reveals complex non-linear interactions between unstable modes. It is found that for most unstable initial conditions, the crystal-melt interface retreats by melting away from the tip region of the encroaching melt-gas interface due to a rise in heat flux as the film thins near the rupture point.

Beerman, Michael

96

Symptomatic chronic long head of biceps rupture: Surgical results  

PubMed Central

Purpose: Chronic rupture of the long head of biceps (LHB) tendon is usually asymptomatic. However, some active patients suffer with long-term cramping pain associated with repetitive biceps use. The aim of this study is to review the outcomes of biceps tenodesis performed for chronic LHB ruptures. Materials and Methods: We performed a retrospective review of 11 consecutive patients who underwent biceps tenodesis for symptomatic chronic LHB ruptures over a 4-year period. Results: There were 10 men and one woman with an average age at surgery of 41 years (range 23-65). The mean follow-up was 29 months (range 6-60). In five cases a tendon was still identifiable and suitable for repair with an 慽n-bone interference screw. However, in six cases the tendon was not possible to tenodese with an interference screw. In these cases we used an 憃n-bone technique with suture anchors. All, except one, patients reported improvement in their arm pain (78%), strength (74%) and appearance. All, except one, were glad to have had the surgery. Conclusions: Symptomatic chronic LHB ruptures improve with a biceps tenodesis procedure. Due to the chronicity of the injury and possible degeneration of the tendon, a suitable tendon for 慽n-bone tenodesis may not be possible. In these cases an 憃n-bone footprint repair with suture anchors achieves good results. Level of Evidence: IV (retrospective case series). PMID:23493581

Ng, Chye Yew; Funk, Lennard

2012-01-01

97

Shear Strength  

NSDL National Science Digital Library

Dr. John Atkinson, of the University of the West of England, developed a site for undergraduate students wanting to learn more about soil classification. His site addresses issues such as: shear strength, peak strength, and residual strength testing. Filled with charts, diagrams, statistics, the information is pertinent and easily understood by almost any audience.

Atkinson, John

2008-10-07

98

Extracellular Matrix Dynamics and Fetal Membrane Rupture  

PubMed Central

The extracellular matrix (ECM) plays an important role in determining cell and organ function: (1) it is an organizing substrate that provides tissue tensile strength; (2) it anchors cells and influences cell morphology and function via interaction with cell surface receptors; and (3) it is a reservoir for growth factors. Alterations in the content and the composition of the ECM determine its physical and biological properties, including strength and susceptibility to degradation. The ECM components themselves also harbor cryptic matrikines, which when exposed by conformational change or proteolysis have potent effects on cell function, including stimulating the production of cytokines and matrix metalloproteinases (MMPs). Collectively, these properties of the ECM reflect a dynamic tissue component that influences both tissue form and function. This review illustrates how defects in ECM synthesis and metabolism and the physiological process of ECM turnover contribute to changes in the fetal membranes that precede normal parturition and contribute to the pathological events leading to preterm premature rupture of membranes (PPROM). PMID:22267536

Strauss,, Jerome F.

2013-01-01

99

Noninterceptive transverse beam diagnostics  

SciTech Connect

The transverse emittance properties of a high-current linear accelerator may be measured by using TV cameras sensitive to the visible radiation emitted following beam interactions with residual gas. This paper describes the TV system being used to measure emittances for the Fusion Materials Irradiation Test (FMIT) project.

Chamberlin, D.D.; Minerbo, G.N.; Teel, L.E. Jr.; Gilpatrick, J.D.

1981-01-01

100

Deconstructed Transverse Mass Variables  

E-print Network

Traditional searches for R-parity conserving natural supersymmetry (SUSY) require large transverse mass and missing energy cuts to separate the signal from large backgrounds. SUSY models with compressed spectra inherently produce signal events with small amounts of missing energy that are hard to explore. We use this difficulty to motivate the construction of "deconstructed" transverse mass variables which are designed preserve information on both the norm and direction of the missing momentum. We demonstrate the effectiveness of these variables in searches for the pair production of supersymmetric top-quark partners which subsequently decay into a final state with an isolated lepton, jets and missing energy. We show that the use of deconstructed transverse mass variables extends the accessible compressed spectra parameter space beyond the region probed by traditional methods. The parameter space can further be expanded to neutralino masses that are larger than the difference between the stop and top masses. In addition, we also discuss how these variables allow for novel searches of single stop production, in order to directly probe unconstrained stealth stops in the small stop- and neutralino-mass regime. We also demonstrate the utility of these variables for generic gluino and stop searches in all-hadronic final states. Overall, we demonstrate that deconstructed transverse variables are essential to any search wanting to maximize signal separation from the background when the signal has undetected particles in the final state.

Ahmed Ismail; Reinhard Schwienhorst; Joseph S. Virzi; Devin G. E. Walker

2014-09-09

101

Ejs Transverse Wave Model  

NSDL National Science Digital Library

The Ejs Transverse Wave model displays the motion of a transverse wave on a string. The simulation allows an arbitrarily polarized wave to be created. The magnitude of the components of the wave and the relative phase between the components of the wave can all be changed via sliders. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting 釵pen Ejs Model from the pop-up menu item. Ejs Transverse Wave 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_ehu_waves_transverse.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave motion are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-19

102

Spontaneous transverse colon volvulus  

PubMed Central

We report a case of spontaneous transverse colon volvulus in a young healthy woman. It constitutes an unusual case since it occurred in a young healthy woman with a subacute onset and no aetiological factor has been found. Its diagnosis is still challenging. Prompt recognition with emergency intervention constitutes the key to successful outcome. PMID:23785565

Sana, Landolsi; Ali, Gassara; Kallel, Helmi; Amine, Baklouti; Ahmed, Saadaoui; Mohamed Ali, Elouer; Wajdi, Chaeib; Saber, Mannai

2013-01-01

103

Traumatic pericardial rupture with skeletonized phrenic nerve  

Microsoft Academic Search

BACKGROUND: Traumatic pericardial rupture is a rare presentation. Pericardial rupture itself is asymptomatic unless complicated by either hemorrhage or herniation of the heart through the defect. Following diagnosis surgical repair of the pericardium is indicated because cardiac herniation may result in vascular collapse and sudden death. OBJECTIVES: Here we present a case of traumatic, non-herniated pericardial rupture with complete skeletonization

Zain Khalpey; Taufiek K Rajab; Jan D Schmitto; Philipp C Camp

2011-01-01

104

A Retrospective Analysis of Ruptured Breast Implants  

PubMed Central

Background Rupture is an important complication of breast implants. Before cohesive gel silicone implants, rupture rates of both saline and silicone breast implants were over 10%. Through an analysis of ruptured implants, we can determine the various factors related to ruptured implants. Methods We performed a retrospective review of 72 implants that were removed for implant rupture between 2005 and 2014 at a single institution. The following data were collected: type of implants (saline or silicone), duration of implantation, type of implant shell, degree of capsular contracture, associated symptoms, cause of rupture, diagnostic tools, and management. Results Forty-five Saline implants and 27 silicone implants were used. Rupture was diagnosed at a mean of 5.6 and 12 years after insertion of saline and silicone implants, respectively. There was no association between shell type and risk of rupture. Spontaneous was the most common reason for the rupture. Rupture management was implant change (39 case), microfat graft (2 case), removal only (14 case), and follow-up loss (17 case). Conclusions Saline implants have a shorter average duration of rupture, but diagnosis is easier and safer, leading to fewer complications. Previous-generation silicone implants required frequent follow-up observation, and it is recommended that they be changed to a cohesive gel implant before hidden rupture occurs.

Baek, Woo Yeol; Lew, Dae Hyun

2014-01-01

105

Rheology and rupture of homogeneous silicate liquids at magmatic temperatures  

NASA Astrophysics Data System (ADS)

Homogeneous silicate liquids have a Newtonian rheology under conditions of modest stress, but under relatively high stress or otherwise imposed high rates of deformation their viscosity may become non-Newtonian before the onset of rupture. This behavior has been discussed semi-empirically as well as in terms of the Maxwell model liquid. Here it is shown that the configurational entropy theory for the occurrence of the glass transition can also explain this non-Newtonian rheology of silicate liquids ranging in composition from silica-rich to silica-poor. The pressure and temperature dependence of the transition from Newtonian to non-Newtonian flow is discussed qualitatively. Geological applications are indicated. Fragmentation of silicate liquids takes place when the glass transition is crossed and the liquid has become solid like. Experimental evidence indicates that the rupture strength is only slightly larger than the stress needed to cause the onset of non-Newtonian rheology.

Bottinga, Y.

1994-05-01

106

Instabilities at frictional interfaces: Creep patches, nucleation, and rupture fronts  

NASA Astrophysics Data System (ADS)

The strength and stability of frictional interfaces, ranging from tribological systems to earthquake faults, are intimately related to the underlying spatially extended dynamics. Here we provide a comprehensive theoretical account, both analytic and numeric, of spatiotemporal interfacial dynamics in a realistic rate-and-state friction model, featuring both velocity-weakening and velocity-strengthening behaviors. Slowly extending, loading-rate-dependent creep patches undergo a linear instability at a critical nucleation size, which is nearly independent of interfacial history, initial stress conditions, and velocity-strengthening friction. Nonlinear propagating rupture fronts梩he outcome of instability梔epend sensitively on the stress state and velocity-strengthening friction. Rupture fronts span a wide range of propagation velocities and are related to steady-state-front solutions.

Bar-Sinai, Yohai; Spatschek, Robert; Brener, Efim A.; Bouchbinder, Eran

2013-12-01

107

Thrust-type subduction-zone earthquakes and seamount asperites: A physical model for seismic rupture  

SciTech Connect

A thrust-type subduction-zone earthquake of M{sub W} 7.6 ruptures an area of {approximately}6,000 km{sup 2}, has a seismic slip of {approximately}1 m, and is nucleated by the rupture of an asperity {approximately}25km across. A model for thrust-type subduction-zone seismicity is proposed in which basaltic seamounts jammed against the base of the overriding plate act as strong asperities that rupture by stick-slip faulting. A M{sub W} 7.6 event would correspond to the near-basal rupture of a {approximately}2-km-tall seamount. The base of the seamount is surrounded by a low shear-strength layer composed of subducting sediment that also deforms between seismic events by distributed strain (viscous flow). Planar faults form in this layer as the seismic rupture propagates out of the seamount at speeds of kilometers per second. The faults in the shear zone are disrupted after the event by aseismic, slow viscous flow of the subducting sediment layer. Consequently, the extent of fault rupture varies for different earthquakes nucleated at the same seamount asperity because new fault surfaces form in the surrounding subducting sediment layer during each fast seismic rupture.

Cloos, M. (Univ. of Texas, Austin (United States))

1992-07-01

108

Partonic Transverse Momentum Distributions  

SciTech Connect

In recent years parton distributions have been generalized to account also for transverse degrees of freedom and new sets of more general distributions, Transverse Momentum Dependent (TMD) parton distributions and fragmentation functions were introduced. Different experiments worldwide (HERMES, COMPASS, CLAS, JLab-Hall A) have measurements of TMDs in semi-inclusive DIS processes as one of their main focuses of research. TMD studies are also an important part of the present and future Drell-Yan experiments at RICH and JPARC and GSI, respectively, Studies of TMDs are also one of the main driving forces of the Jefferson Lab (JLab) 12 GeV upgrade project. Progress in phenomenology and theory is flourishing as well. In this talk an overview of the latest developments in studies of TMDs will be given and newly released results, ongoing activities, as well as planned near term and future measurements will be discussed.

Rossi, Patrizia [Laboratori Nazionali di Frascati-INFN, Via E. Fermi 40, 00044 Frascati (Italy)

2010-08-04

109

[Ettore Majoran's transversal epistemology].  

PubMed

Il valore delle leggi statistiche nella fisica e nelle scienze sociali is Ettore Majorana's only work on science. It offers a critique of classical determinism, establishing an analogy between the laws of quantum mechanics and social science and arguing that both are intrinsically linked to probability. This article first studies this argument from the standpoing of metaphysics, physics, and sociology, and then assesses the significance of this transversal epistemology. PMID:23636783

Bontems, Vincent

2013-01-01

110

The tensile strength and ductility of continuous fibre composites  

Microsoft Academic Search

The plastic instability approach has been applied to the tensile behaviour of a continuous fibre composite. It is shown that the combination of two components with different strengths and degrees of work-hardening produces a new material with a new degree of work-hardening, which may be determined by the present analysis. Expressions for the elongation at rupture and the strength of

S. T. Mileiko

1969-01-01

111

Transverse spectral velocity estimation.  

PubMed

A transverse oscillation (TO)-based method for calculating the velocity spectrum for fully transverse flow is described. Current methods yield the mean velocity at one position, whereas the new method reveals the transverse velocity spectrum as a function of time at one spatial location. A convex array probe is used along with two different estimators based on the correlation of the received signal. They can estimate the velocity spectrum as a function of time as for ordinary spectrograms, but they also work at a beam-to-flow angle of 90. The approach is validated using simulations of pulsatile flow using the Womersly-Evans flow model. The relative bias of the mean estimated frequency is 13.6% and the mean relative standard deviation is 14.3% at 90, where a traditional estimator yields zero velocity. Measurements have been conducted with an experimental scanner and a convex array transducer. A pump generated artificial femoral and carotid artery flow in the phantom. The estimated spectra degrade when the angle is different from 90, but are usable down to 60 to 70. Below this angle the traditional spectrum is best and should be used. The conventional approach can automatically be corrected for angles from 0 to 70 to give fully quantitative velocity spectra without operator intervention. PMID:25389160

Jensen, J鴕gen

2014-11-01

112

Traumatically ruptured globes in children.  

PubMed

This retrospective study was designed to document the etiology of traumatically ruptured globes in children and to determine the prognostic value of several clinical parameters with respect to visual outcome. Forty-six children 16 years of age and under seen in the emergency room over a 2-year period were found to have full thickness penetration of the globe. Fifty-nine percent of injuries occurred during recreational activities, and 59% occurred outside of the home. Boys outnumbered girls by a 6:1 ratio. For children, initial visual acuity proved to be less valuable as a prognostic indicator with regard to final vision than has been reported in adults. Smaller corneal wounds offered better visual outcomes. Four eyes were enucleated. Ten ruptures (22%) were related to activity involving guns. Four of six BB gun injuries were the result of a ricocheted BB. Visual outcomes in gun-related injuries were particularly poor. PMID:7837018

Rudd, J C; Jaeger, E A; Freitag, S K; Jeffers, J B

1994-01-01

113

Achilles tendon rupture in badminton.  

PubMed Central

The typical badminton player with an Achilles tendon rupture is 36 years old and, despite limbering up, is injured at the rear line in a sudden forward movement. He resumes work within three months and has a slight lack of dorsiflexion in the ankle as the main complication. Most patients resume badminton within one year, but some finish their sports career, mainly due to fear of a new injury. The investigation discusses predisposing factors and prophylactic measures. PMID:2605439

Kaalund, S; Lass, P; H鴊saa, B; N鴋r, M

1989-01-01

114

Strength Testing.  

ERIC Educational Resources Information Center

Postural deviations resulting from strength and flexibility imbalances include swayback, scoliosis, and rounded shoulders. Screening tests are one method for identifying strength problems. Tests for the evaluation of postural problems are described, and exercises are presented for the strengthening of muscles. (JN)

Londeree, Ben R.

1981-01-01

115

Ideas in transverse spin physics  

E-print Network

Three simple ideas about transverse spin observables are presented for the purpose of stimulating discussion. The manuscript is based on a presentation at the "Transversity 2014" workshop in Torre Chia, Sardinia, Italy on June 9-13, 2014 where approximately sixty experts on transverse spin physics had gathered to share recent results in an atmosphere of sun-drenched intensity.

Dennis Sivers

2014-09-08

116

Characteristics of thermally-induced transverse cracks in graphite epoxy composite laminates  

NASA Technical Reports Server (NTRS)

The characteristics of thermally induced transverse cracks in T300/5208 graphite-epoxy cross-ply and quasi-isotropic laminates were investigated both experimentally and analytically. The formation of transverse cracks and the subsequent crack spacing present during cool down to -250 F (116K) and thermal cycling between 250 and -250 F (116 and 394K) was investigated. The state of stress in the vicinity of a transverse crack and the influence of transverse cracking on the laminate coefficient of thermal expansion (CTE) was predicted using a generalized plane strain finite element analysis and a modified shear lag analysis. A majority of the cross-ply laminates experienced transverse cracking during the initial cool down to -250 F whereas the quasi-isotropic laminates remained uncracked. The in situ transverse strength of the 90 degree layers was more than 1.9 times greater than the transverse strength of the unidirectional 90 degree material for all laminates investigated.

Adams, D. S.; Bowles, D. E.; Herakovich, C. T.

1983-01-01

117

Method and apparatus for determining tensile strength  

DOEpatents

A method and apparatus for determining the statistical distribution of apparent tensile strength of rock, the size effect with respect to tensile strength, as well as apparent deformation modulus of both intact and fractured or jointed rock. The method is carried out by inserting a plug of deformable material, such as rubber, in an opening of a specimen to be tested. The deformable material is loaded by an upper and lower platen until the specimen ruptures, whereafter the tensile strength is calculated based on the parameters of the test specimen and apparatus.

Ratigan, Joe L. (Rapid City, SD)

1984-01-01

118

Method and apparatus for determining tensile strength  

DOEpatents

A method and apparatus is described for determining the statistical distribution of apparent tensile strength of rock, the size effect with respect to tensile strength, as well as apparent deformation modulus of both intact and fractured or jointed rock. The method is carried out by inserting a plug of deformable material, such as rubber, in an opening of a specimen to be tested. The deformable material is loaded by an upper and lower platen until the specimen ruptures, whereafter the tensile strength is calculated based on the parameters of the test specimen and apparatus.

Ratigan, J.L.

1982-05-28

119

Transversality for Holomorphic Supercurves  

NASA Astrophysics Data System (ADS)

Holomorphic supercurves are motivated by supergeometry as a natural generalisation of holomorphic curves. In the characterisation as a tuple consisting of a holomorphic curve and certain sections, we consider a slightly weaker form of the defining equations. This is such that, upon perturbing them to depend on a connection, the corresponding linearised operator is generically surjective. By this transversality result, we show that the resulting moduli spaces are oriented finite dimensional smooth manifolds. Finally, we examine how they depend on the choice of generic data. A companion article establishes compactness results in this context.

Groeger, Josua

2014-10-01

120

Neutron Transversity at Jefferson Lab  

SciTech Connect

Nucleon transversity and single transverse spin asymmetries have been the recent focus of large efforts by both theorists and experimentalists. On-going and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton or the deuteron. Presented here is a planned measurement of the neutron transversity and single target spin asymmetries at Jefferson Lab in Hall A using a transversely polarized {sup 3}He target. Also presented are the results and plans of other neutron transverse spin experiments at Jefferson Lab. Finally, the factorization for semi-inclusive DIS studies at Jefferson Lab is discussed.

Jian-Ping Chen; Xiaodong Jiang; Jen-chieh Peng; Lingyan Zhu

2005-09-07

121

[Rupture of the diaphragm of late manifestation].  

PubMed

Twenty one cases of delayed diagnosis of ruptured diaphragm caused by closed trauma are reported: 14 on the left side and 7 on the right side. The clinical signs and the modes of presentation are non-specific. Although the history of thoraco-abdominal trauma and the chest x-ray are sufficient to establish the diagnosis of rupture of the left hemidiaphragm, they can only suggest the diagnosis in cases of righ-sided rupture. The mechanism of rupture is more often due to sudden reflex contraction of the diaphragm against a closed glottis than to excessive abdominal pressure caused by the trauma. Diaphragmatic rupture due to closed trauma causes large tears exposing the patient to a low risk of strangulation of intestinal structures in contrast with ruptures due to a penetrating injury, which causes small tears. The diaphragmatic domes must be systematically explored during laparotomy or thoracotomy performed for thoraco-abdominal trauma. PMID:2189337

Lenot, B; Bellenot, F; Regnard, J F; Dartevelle, P; Rojas-Miranda, A; Levasseur, P

1990-01-01

122

Early second trimester uterine scar rupture.  

PubMed

Spontaneous uterine scar rupture can be lethal in pregnant women. A spontaneous uterine scar rupture in the early mid-trimester is rare and difficult to diagnose. This is a case of a 30-year-old woman (G2P1L1) at 19 weeks of gestation and having undergone a previous caesarean section presented with acute abdomen in shock. Laparotomy revealed a uterine scar rupture, which was resutured after evacuation of products of conception. This case merits that the uterine rupture should be considered as a differential diagnosis in pregnant women presenting with acute abdomen. In this case, although there was uterine rupture in the second trimester and a complete placental separation, fetus was alive which is quite unusual in patients presenting with rupture uterus. PMID:24326433

Bharatnur, Sunanda; Hebbar, Shripad; Shyamala, G

2013-01-01

123

Delayed aortic rupture following perforating trauma  

PubMed Central

The immediate death rate for aortic rupture caused by pointed and sharp-edged instruments is very high; however, delayed aortic rupture following the trauma is rarely reported. A patient who had an upper abdominal stab wound was sent to our hospital, and an emergency exploratory laparotomy was performed. No traumatic aortic rupture was found at that time. However, on the fifth day after surgery, aortic rupture occurred, and a large retroperitoneal hematoma was formed. The patient eventually died. Aortic rupture was confirmed by a second emergency exploratory laparotomy and the autopsy. The information from exploratory laparotomies, post-operative observations and treatments, medical imaging reports, and reasons for delayed aortic rupture, as well as the underlying pathophysiological processes, are discussed in this case report.

Yang, Xuefei; Xia, Ligang

2014-01-01

124

Transverse Spin Physics at COMPASS  

E-print Network

The study of transverse spin effects is part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. COMPASS investigates the transversity PDFs in semi-inclusive DIS, using a longitudinally polarized muon beam of 160 GeV/c impinging on a transversely polarized target. From 2002 to 2004, data have been collected using a $^6$LiD target transversely polarized. Transversity has been measured using different quark polarimeters: the azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of baryons ($\\Lambda$ hyperons). All the asymmetries have been found to be small, and compatible with zero, a result which has been interpreted as a cancellation between the u and d-quark contributions. In 2007 COMPASS has taken data using a NH$_3$ polarized proton target which will give complementary information on transverse spin effects.

Federica Sozzi; for the COMPASS Collaboration

2009-02-02

125

Investigation of cryogenic rupture disc design  

NASA Technical Reports Server (NTRS)

Rupture disc designs of both the active (command actuated) and passive (pressure ruptured) types were evaluated for performance characteristics at cryogenic temperatures and for capability to operate in a variety of cryogens, including gaseous and liquid fluorine. The test results, coupled with information from literature and industry searches, were used to establish a statement of design criteria and recommended practices for application of rupture discs to cryogenic rocket propellant feed and vent systems.

Keough, J. B.; Oldland, A. H.

1973-01-01

126

Nondestructive Evaluation and Monitoring Results from COPV Accelerated Stress Rupture Testing, NASA White Sands Test Facility (WSTF)  

NASA Technical Reports Server (NTRS)

Develop and demonstrate NDE techniques for real-time characterization of CPVs and, where possible, identification of NDE capable of assessing stress rupture related strength degradation and/or making vessel life predictions (structural health monitoring or periodic inspection modes). Secondary: Provide the COPV user and materials community with quality carbon/epoxy (C/Ep) COPV stress rupture progression rate data. Aid in modeling, manufacturing, and application of COPVs for NASA spacecraft.

Saulsberry Regor

2010-01-01

127

Material Parameters for Creep Rupture of Austenitic Stainless Steel Foils  

NASA Astrophysics Data System (ADS)

Creep rupture properties of austenitic stainless steel foil, 347SS, used in compact recuperators have been evaluated at 700 癈 in the stress range of 54-221 MPa to establish the baseline behavior for its extended use. Creep curves of the foil show that the primary creep stage is brief and creep life is dominated by tertiary creep deformation with rupture lives in the range of 10-2000 h. Results are compared with properties of bulk specimens tested at 98 and 162 MPa. Thin foil 347SS specimens were found to have higher creep rates and higher rupture ductility than their bulk specimen counterparts. Power law relationship was obtained between the minimum creep rate and the applied stress with stress exponent value, n = 5.7. The value of the stress exponent is indicative of the rate-controlling deformation mechanism associated with dislocation creep. Nucleation of voids mainly occurred at second-phase particles (chromium-rich M23C6 carbides) that are present in the metal matrix by decohesion of the particle-matrix interface. The improvement in strength is attributed to the precipitation of fine niobium carbides in the matrix that act as obstacles to the movement of dislocations.

Osman, H.; Borhana, A.; Tamin, M. N.

2014-08-01

128

Neck curve polynomials in neck rupture model  

SciTech Connect

The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of {sup 280}X{sub 90} with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.

Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul [Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung 40132 (Indonesia)

2012-06-06

129

Spontaneous rupture of uterine leiomyoma during labour.  

PubMed

Uterine rupture in labour requires an emergency caesarean section. In women with a uterine scar, either from gynaecological surgery or from a previous caesarean section, it is well documented that the risk of rupture is higher than in those without. Spontaneous uterine rupture in a uterus with fibroids during pregnancy or labour is extremely rare. We present a case of a 33-year-old, unbooked pregnant woman from Nigeria who had a uterine rupture secondary to fibroids. She required an emergency caesarean section in labour. The fibroids were not removed. Her baby was born alive and in good condition and she made an uneventful recovery. PMID:25199188

Ramskill, Nikki; Hameed, Aisha; Beebeejaun, Yusuf

2014-01-01

130

Impact of taping after finger flexor tendon pulley ruptures in rock climbers.  

PubMed

Flexor tendon pulley ruptures are the most common injury in rock climbers. Therapeutic standards usually include a prolonged use of taping applied as a replacement for the lost pulley in a circular fashion at the base of the proximal phalanx. Our biomechanical considerations, however, suggest a new taping method, the H-tape. The purpose of the study is to evaluate whether this new taping method can effectively change the course of the flexor tendon and therefore reduce the tendon-bone distance. In order to compare the effects of different taping methods described in the literature with the newly developed taping method, we performed standardized ultrasound examinations of 8 subjects with singular A2 pulley rupture and multiple pulley ruptures of A2 and A3 pulleys and determined the respective tendon-bone distance for the different taping methods, versus without tape at a preset position on the proximal phalanx. In a second approach, we evaluated the effect of the new taping method on the strength of the injured finger using a force platform on 12 subjects with different pulley ruptures with injuries older than 1 year. The new taping method decreased the tendon-bone distance in the injured finger significantly by 16%, whereas the other taping methods did not. The strength development was significantly better with the new tape for the crimp grip position (+13%), but there was no significant improvement for the hanging position. We recommend taping with the newly presented taping technique after pulley rupture. PMID:17585178

Schoffl, Isabelle; Einwag, Frank; Strecker, Wolf; Hennig, Friedrich; Schoffl, Volker

2007-02-01

131

Transversity Physics at Compass  

E-print Network

Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN, which started taking data in 2002, scattering 160 GeV/c muon beam on a polarized $^6$LiD target. The analysis of the data taken with the target polarized orthogonally to the muon beam direction has allowed to measure for the first time the Collins and Sivers asymmetries of the deuteron. Both for the positive and the negative hadrons produced in semi-inclusive DIS the measured asymmetries are small and, within errors, compatible with zero: results on part of the accumulated statistics have already been published. Two-hadron asymmetries and $\\Lambda$ polarization transfered from the struck quark are also being investigated, and preliminary results on the data collected in the years 2002 and 2003 are given.

F. Bradamante

2006-02-06

132

Effect of Sediments on Rupture Dynamics of Shallow Subduction Zone Earthquakes and Tsunami Generation  

NASA Astrophysics Data System (ADS)

Low-velocity fault zones have long been recognized for crustal earthquakes by using fault-zone trapped waves and geodetic observations on land. However, the most pronounced low-velocity fault zones are probably in the subduction zones where sediments on the seafloor are being continuously subducted. In this study I focus on shallow subduction zone earthquakes; these earthquakes pose a serious threat to human society in their ability in generating large tsunamis. Numerous observations indicate that these earthquakes have unusually long rupture durations, low rupture velocities, and/or small stress drops near the trench. However, the underlying physics is unclear. I will use dynamic rupture simulations with a finite-element method to investigate the dynamic stress evolution on faults induced by both sediments and free surface, and its relations with rupture velocity and slip. I will also explore the effect of off-fault yielding of sediments on the rupture characteristics and seafloor deformation. As shown in Ma and Beroza (2008), the more compliant hanging wall combined with free surface greatly increases the strength drop and slip near the trench. Sediments in the subduction zone likely have a significant role in the rupture dynamics of shallow subduction zone earthquakes and tsunami generation.

Ma, S.

2011-12-01

133

Effect of slag and silica fume on mechanical properties of high strength concrete  

SciTech Connect

This paper presents the study on changes of the mechanical properties, including compressive strength, split tensile strength and rupture strength of four high strength concretes, caused by the addition of ground blast-furnace slag and silica fume. The study indicates that the mechanical properties of high strength concrete were improved to a great extent at later ages when cement used in concrete was replaced by slag and silica fume by 25% by weight.

Li Jianyong; Tian Pei [China Building Materials Academy, Beijing (China). Building Materials and Concrete Research Inst.] [China Building Materials Academy, Beijing (China). Building Materials and Concrete Research Inst.

1997-06-01

134

Ruptured liver abscess in a neonate.  

PubMed

We report a rare case of 17-day-old neonate, diagnosed to have ruptured liver abscess secondary to Methicillin-resistant Staphylococcal aureus infection. The child presented with septicemia and abdominal distension. On exploration, there was pyoperitoneum with ruptured liver abscess. PMID:22382113

Jain, Prashant; Mishra, Ashwani; Agarawal, Vyom

2012-01-01

135

Dynamic Interface Rupture in Extremely Heterogeneous Media  

Microsoft Academic Search

Fracture experiments of monolithic brittle materials usually show the maximum speed of smooth rupture at some 30 % of the relevant shear wave speed. This experimental maximum rupture speed is by far lower than those predicted by theories and inferred from inversions of seismograms, and some seismic inversions (e.g., the 1979 Imperial Valley, 1992 Landers, 1999 Izmit, 2001 the central

K. Uenishi; K. Tsuji

2007-01-01

136

Longitudinal ruptures of polyester knitted vascular prostheses  

Microsoft Academic Search

Aim: The purpose of the study was the characterization of a type of rupture occurring on warp-knitted polyester vascular prostheses. Materials and Methods: We studied 20 cases of warp-knitted polyester vascular prostheses that were explanted from humans that showed a longitudinal rupture as a part of a collaborative retrieval program. All the prostheses were immediately fixed in a 10% formaldehyde

Nabil Chakfe; Gunnar Riepe; Florence Dieval; Jean-Francois Le Magnen; Lu Wang; Elisabeth Urban; Marc Beaufigeau; Bernard Durand; Herbert Imig; Jean-Georges Kretz

2001-01-01

137

Rupture Velocity of Plane Strain Shear Cracks  

Microsoft Academic Search

Propagation of plane strain shear cracks is calculated numerically by using finite difference equations with second-order accuracy. The rupture model, in which stress drops gradually as slip increases, combines two different rupture criteria: (1) slip begins at a finite stress level; (2) finite energy is absorbed per unit area as the crack advances. Solutions for this model are nonsingular. In

D. J. Andrews

1976-01-01

138

Transverse Spin Effects at COMPASS  

E-print Network

The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a transversely polarized 6LiD target. In 2007, a transversely polarized NH3 target was used. Three different channels to access the transversity distribution function have been analyzed: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of lambda hyperons in the final state. Transverse quark momentum effects in a transversely polarized nucleon have been investigated by measuring the Sivers distribution function. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries using spin-averaged 6LiD data.

C. Schill

2009-09-29

139

Genetic basis of cranial cruciate ligament rupture (CCLR) in dogs.  

PubMed

Cranial Cruciate Ligament rupture (CCLR) is one of the most common forms of lameness in dogs and is analogous to rupture of the anterior cruciate ligament in humans, for which it can serve as a model. As there is a strong breed-related predisposition to CCLR in dogs, a study was undertaken to consider putative genetic components in susceptible dog breeds. A candidate gene, single nucleotide polymorphism (SNP) genotyping approach using MALDI-TOF mass spectrometry (Sequenom Ltd) was designed to investigate several CCLR-susceptible dog breeds and identify CCLR-associated genes/gene regions that may confer susceptibility or resistance. A meta-analysis was performed using the breed case/control candidate gene data to identify SNP associations that were common to the whole cohort of susceptible dogs. We identified SNPs in key genes involved in ligament strength, stability and extracellular matrix formation (COL5A1, COL5A2, COL1A1, COL3A1, COL11A1, COL24A1, FBN1, LOX, LTBP2) which were significantly associated with CCLR susceptibility across the dog breeds used in this study. These SNPs could have an involvement in CCLR due to a detrimental effect on ligament structure and strength. This is the first published candidate gene study that has revealed significant genetic associations with canine CCLR. PMID:24684544

Baird, Arabella Elizabeth Gardiner; Carter, Stuart D; Innes, John F; Ollier, William E; Short, Andrea D

2014-08-01

140

Spontaneous splenic rupture in a hemodialysis patient.  

PubMed

Spontaneous splenic rupture (SSR) in a patient undergoing hemodialysis has been described as an extremely rare and potentially fatal complication. We report here spontaneous splenic rupture in a 52-year-old woman undergoing regular hemodialysis for end-stage renal disease (ESRD). She complained of colicky abdominal pain in the left upper quadrant area and dizziness when she assumed an upright posture. Her vital signs revealed low blood pressure and tachycardia, which was suggestive of hypovolemic shock. Abdomen CT scan showed splenic hematoma and hemoperitoneum. However, she had no history of any event triggering the splenic rupture. An exploratory laparotomy showed a ruptured spleen and an emergency splenectomy was performed. We suggest that spontaneous spleen rupture may be attributed to uremic coagulopathy and heparin-induced coagulopathy. PMID:15988818

Kim, Hyun Jung; Lee, Gyeong Won; Park, Dong Jun; Lee, Jong Deog; Chang, Se Ho

2005-06-30

141

Intermediate Temperature Stress Rupture of a Woven Hi-Nicalon, BN-Interphase, SiC Matric Composite in Air  

NASA Technical Reports Server (NTRS)

Woven Hi-Nicalon (TM) reinforced melt-infiltrated SiC matrix composites were tested under tensile stress-rupture conditions in air at intermediate temperatures. A comprehensive examination of the damage state and the fiber properties at failure was performed. Modal acoustic emission analysis was used to monitor damage during the experiment. Extensive microscopy of the composite fracture surfaces and the individual fiber fracture surfaces was used to determine the mechanisms leading to ultimate failure. The rupture properties of these composites were significantly worse than expected compared to the fiber properties under similar conditions. This was due to the oxidation of the BN interphase. Oxidation occurred through the matrix cracks that intersected the surface or edge of a tensile bar. These oxidation reactions resulted in minor degradation to fiber strength and strong bonding of the fibers to one another at regions of near fiber-to-fiber contact. It was found that two regimes for rupture exist for this material: a high stress regime where rupture occurs at a fast rate and a low stress regime where rupture occurs at a slower rate. For the high stress regime, the matrix damage state consisted of through thickness cracks. The average fracture strength of fibers that were pulled-out (the final fibers to break before ultimate failure) was controlled by the slow-crack growth rupture criterion in the literature for individual Hi-Nicalon (TM) fibers. For the low stress regime, the matrix damage state consisted of microcracks which grew during the rupture test. The average fracture strength of fibers that were pulled-out in this regime was the same as the average fracture strength of individual fibers pulled out in as-produced composites tested at room temperature.

Morscher, Gregory N.; Hurst, Janet; Brewer, David

1999-01-01

142

Transverse Spin Physics at COMPASS  

E-print Network

The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. Three channels have been analyzed at COMPASS to access the transversity distribution function: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of Lambda hyperons in the final state. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum k_T in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries using spin-averaged 6LiD data.

Christian Schill; for the COMPASS collaboration

2010-09-04

143

Dynamic Interface Rupture in Extremely Heterogeneous Media  

NASA Astrophysics Data System (ADS)

Fracture experiments of monolithic brittle materials usually show the maximum speed of smooth rupture at some 30 % of the relevant shear wave speed. This experimental maximum rupture speed is by far lower than those predicted by theories and inferred from inversions of seismograms, and some seismic inversions (e.g., the 1979 Imperial Valley, 1992 Landers, 1999 Izmit, 2001 the central Kunlunshan and 2002 Denali earthquakes) even suggest the existence of supershear rupture speeds (i.e., rupture propagating faster than the relevant shear wave). Recently, Uenishi et al. ( SSJ Fall Meeting, 2004, 2005; AGU Fall Meeting, 2006) experimentally investigated dynamic fracture in monolithic hyperelastic materials under static mode- loading conditions with relatively high crack-parallel stresses. Using a high-speed digital video camera system, they showed that cracks may propagate supersonically even in homogeneous materials. However, the exact mechanism for rupture nucleation and the transition of a nucleated rupture from sub-Rayleigh to super-shear rupture speed has not been identified yet. In this contribution, we further develop our experimental system and investigate dynamic fracture in extremely heterogeneous media, consisting of thin fluid and solid films: Inside a wire frame (50mm high, 50mm wide), a flat soap film contacts a flat thin solid plastic film (20mm high, 20mm wide), under static tensile loading conditions. The rupture (crack), initiated at a point, propagates subsonically in the linear elastic fluid film (see e.g., Uenishi et al., SSJ Fall Meeting, 2006, for the dynamic rupture in monolithic fluid films). When the circular rupture front reaches the interface, the rupture advances along the interface and then it is "diffracted" at the two corners of the interface. We record the rupture propagation process utilizing our high-speed digital video camera at a frame rate of 20 ?s (2010-6s). The observed results show that interface rupture propagation may accelerate (or even decelerate) and the dynamic rupture behavior is very sensitive to the geometry of the interface between the two films: (1) When the subsonic rupture front reaches the first rectangular corner, it accelerates around the corner and then advances supersonically along the interface; and (2) when the supersonic interface rupture front approaches the second corner (obtuse with respect to the rupture front in fluid), it bifurcates for a short period (400 ?s): the first branch unexpectedly expands rather straight into the bulk and the second one propagates along the interface at a lower speed; At a later stage, again unexpectedly, the first branched crack decelerates significantly in the bulk and the two cracks eventually merge into a single crack. The overall behavior is - in some sense - similar to that of the oblique shock and Prandtl- Meyer expansion waves in fluid mechanics, and it might give new insights not only into the question of high rupture speeds of natural earthquakes but also into the generation mechanism of tsunamis. u.ac.jp/~uenishi/

Uenishi, K.; Tsuji, K.

2007-12-01

144

Formability Studies on Transverse Tailor Welded Blanks  

NASA Astrophysics Data System (ADS)

Tailor Welded Blanks (TWB) technology is one of the several approaches that have been used to reduce the weight of the automobile body. TWBs are made up of two or more blanks having different/same properties (geometry, material etc.) prior to forming. The formability of these blanks depends on material and geometric parameters like strength ratio and thickness ratio. The study of these blanks can be classified on the basis of the weld orientation chosen viz. transverse weld or longitudinal weld with respect to the major straining direction. This paper studies the formability issues related to transverse TWB by FE simulation. The formability is assessed by analyzing tensile and Limit Dome Height (LDH) tests. The weld region is assumed to be a line in all the simulations. While modeling the tensile test, ultimate tensile strength (UTS) and elongation are monitored, and in LDH testing, pole height and maximum load (in near plane strain condition) are monitored. LDH testing shows that as thickness ratio increases, the load bearing capacity and the pole height decreases. There is a contribution from both the thicker and the thinner blank to the overall deforming volume. Failure location analysis shows that there is an abrupt change in the location of the failure from punch nose region to weld line region as the thickness ratio reaches a critical magnitude (1.08). The study of material properties shows that as the yield strength ratio (S ratio) and strain hardening exponent ratio (N ratio) between the blanks increases, the maximum load which the blank can sustain without failure (UTS) increases. This becomes constant and comparable to that of single sheet at higher N and S ratios.

Bhaskar, V. Vijay; Narasimhan, K.

2005-08-01

145

Formability Studies on Transverse Tailor Welded Blanks  

SciTech Connect

Tailor Welded Blanks (TWB) technology is one of the several approaches that have been used to reduce the weight of the automobile body. TWBs are made up of two or more blanks having different/same properties (geometry, material etc.) prior to forming. The formability of these blanks depends on material and geometric parameters like strength ratio and thickness ratio. The study of these blanks can be classified on the basis of the weld orientation chosen viz. transverse weld or longitudinal weld with respect to the major straining direction.This paper studies the formability issues related to transverse TWB by FE simulation. The formability is assessed by analyzing tensile and Limit Dome Height (LDH) tests. The weld region is assumed to be a line in all the simulations. While modeling the tensile test, ultimate tensile strength (UTS) and elongation are monitored, and in LDH testing, pole height and maximum load (in near plane strain condition) are monitored. LDH testing shows that as thickness ratio increases, the load bearing capacity and the pole height decreases. There is a contribution from both the thicker and the thinner blank to the overall deforming volume. Failure location analysis shows that there is an abrupt change in the location of the failure from punch nose region to weld line region as the thickness ratio reaches a critical magnitude (1.08).The study of material properties shows that as the yield strength ratio (S ratio) and strain hardening exponent ratio (N ratio) between the blanks increases, the maximum load which the blank can sustain without failure (UTS) increases. This becomes constant and comparable to that of single sheet at higher N and S ratios.

Bhaskar, V. Vijay; Narasimhan, K. [Dept of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Powai, Bombay 400 076 (India)

2005-08-05

146

Age at intracranial aneurysm rupture among generations  

PubMed Central

Background: Previous studies have reported intracranial aneurysm (IA) occurring at young ages in subsequent generations. These studies did not correct for duration of follow-up. Second-generation members who would have their ruptured IA late in life may not be detected due to shorter follow-up time than the first generation. We examined families in which ruptured IA occurred in two consecutive generations for the hypothesis that the second generation (F1) was more likely to have a rupture at a younger age than the older generation (F0). Methods: The Familial Intracranial Aneurysm (FIA) Study is a multicenter, international study recruiting families of ruptured and unruptured IA. All available family members are interviewed. Cox proportional hazards regression models and Kaplan-Meier curves were used to examine differences by generation. Results: Although we found that the F1 generation was more likely to have an aneurysm rupture at a younger age than the F0 generation, we found that this was largely because of a lack of follow-up time in the F1 generation. The F1 generation had 50% the rupture rate of the prior generation. When analyzed by Kaplan-Meier curves, we found a tendency to have a slightly later rupture rate in the F1 generation once time to follow-up was included in the analysis model. Conclusions: Families of ruptured intracranial aneurysm (IA) do not appear to demonstrate 揳nticipation. Our finding suggests that genetic epidemiology of ruptured IA should examine all types of variations such as single base-pair changes, deletions, insertions, and other variations that do not demonstrate anticipation. GLOSSARY FIA = familial intracranial aneurysm; IA = intracranial aneurysm; SAH = subarachnoid hemorrhage. PMID:19237697

Woo, D; Hornung, R; Sauerbeck, L; Brown, R; Meissner, I; Huston, J; Foroud, T; Broderick, J

2009-01-01

147

Transverse Spin Effects at COMPASS  

E-print Network

Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized nucleon targets have been under intense experimental investigation over the past few years. They provide new insights into QCD and the nucleon structure. For instance, they allow the determination of the third yet-unknown leading-twist quark distribution function $\\Delta_{T}q(x)$, the transversity distribution. Additionally, they give insight into the parton transverse momentum distribution and angular momentum. The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. In the years 2002-2004 data were collected scattering a 160 GeV muon beam on a transversely polarized deuteron target. In 2007, additional data were collected on a transversely polarized proton target. New results from the analysis of the proton data will be presented. A different but not less important insight into the nucleon structure might be given by the Sivers asymmetry. This angular dependence of the cross-section arises from an intrinsic asymmetry in the parton transverse momentum distribution. The Sivers function is tightly related to the total angular momentum carried by the quarks in the nucleon. New COMPASS results for the Sivers asymmetry of the proton will be shown.

H. Wollny

2009-02-03

148

Application of high-velocity friction experiments to the shear rupture of a fault in an elastic half-space  

NASA Astrophysics Data System (ADS)

We developed a physics-based model for earthquake rupture by numerically simulating shear rupture along a 2D vertical fault with the dynamic frictional strength of granite under high slip velocity. Recent experimental observations indicated that the steady-state frictional strength of silica-rich igneous rocks (granite, syenite, diorite) alternate between dynamic-weakening under low velocity (V < 0.03 m/s) and dynamic-strengthening under higher velocities (V > 0.03 m/s). This strength alternation was attributed to powder-lubrication (weakening), and powder dehydration (strengthening) (Sammis et al., 2011). We used the dynamic friction law which was determined on samples of Sierra White granite under experimental velocities approaching 1 m/s (Reches and Lockner, 2010). We converted their observed friction-distance-velocity relations into an empirical friction model referred to as WEST (WEakening - STrengthening). For the simulation calculations, we used the spectral element code of Ampuero (web.gps.caltech.edu/~ampuero/software), which computes the spontaneous rupture propagation along an anti-plane shear (mode III) fracture in an elastic half-space. In the present analysis, the WEST friction model is used as the fault strength while keeping all other parameters (crust properties and stresses) the same as Version 3 of the Southern California Earthquake Center (SCEC) benchmark problem (Harris et al., 2004). This approach allows for direct comparison between the WEST rupture and the benchmark rupture with a fault of slip-weakening friction model (Rojas et al., 2008). We found the following differences between the ruptures of the two models: (1) WEST-based rupture occurs earlier at all observation points away from the nucleation zone; (2) WEST-based model has lower (~ 35%) peak velocity and shorter rise-time; and (3) WEST-based rupture shows rich, frequent alteration of slip velocity, and consequently, the simulated rupture is more complex in stress drop, displacements, and friction recovery. We discuss the significant contribution of this experimentally-based friction model to the understanding of rupture models with emphasis on slip-pulse behavior.

Liao, Zonghu; Reches, Zeev

2013-04-01

149

Fragmentation of transversely polarized quarks probed in transverse momentum distributions  

Microsoft Academic Search

It is shown that the azimuthal dependence of the distribution of hadrons in a quark jet is a probe of the transverse spin of the quark initiating the jet. This results in a new spin-dependent fragmentation function that acts at the twist-2 level. One example of a process where it contributes is semi-inclusive deeply inelastic scattering with a transversely polarized

John Collins

1993-01-01

150

Transverse spin effects in COMPASS  

E-print Network

In the years 2002-2004 COMPASS has collected data with the LiD target polarization oriented transversely with respect to the muon beam direction for about 20% of the running time, to measure transverse spin effects in semi-inclusive deep inelastic scattering, one of the main objectives of the COMPASS spin program. In 2007, COMPASS has used for the first time a proton NH_3 target with the data taking time equally shared between longitudinal and transverse polarization of the target. After reviewing the results obtained with the deuteron, the new results for the Collins and Sivers asymmetries of the proton will be presented.

A. Bressan; for the COMPASS experiment

2009-02-02

151

Management of traumatic aortic rupture.  

PubMed

A traumatic thoracic aortic injury is a severe and life-threatening clinical entity. Although largely fatal; if untreated, these injuries are amenable to surgical repair if appropriately diagnosed. Therefore, early triage of this condition is critically important. Unfortunately, aortic injuries rarely occur in isolation, and there has been no good cutoff value to help select the appropriate surgical strategy. Algorithms for the both diagnosis and treatment of traumatic thoracic aortic injury have undergone changes in recent years. There have been several case reports, retrospective series and registry data describing the treatment of patients with traumatic thoracic aortic rupture using endovascular treatment. Endovascular treatment is a less-invasive management option for polytraumatized patients. Because it is less invasive, without the need for thoracotomy or the use of heparin, endovascular repair can be performed even in acutely injured patients, without the risk of destabilizing pulmonary, head or abdominal traumatic lesions. Long-term follow-up especially in young patients is necessary after endovascular treatment. PMID:23338596

Watanabe, Ken-ichi; Fukuda, Ikuo; Asari, Yasushi

2013-12-01

152

Rupture of lenticulostriate artery aneurysms.  

PubMed

The authors report on 3 rare cases of ruptured lenticulostriate artery (LSA) aneurysms that were heralded by deep cerebral hematomas. The hematomas were unilateral in 2 cases and bilateral in 1; in the bilateral case, only a single LSA aneurysm could be identified on the right side of the brain. Because of their small size (? 2 mm), fusiform aspect, and deep location within the brain, all of the aneurysms were treated conservatively. There was no hemorrhage recurrence, and follow-up angiography demonstrated spontaneous thrombosis in 2 of the 3 cases. The clinical course was favorable in 2 of the 3 patients. The course in the patient with the bilateral hematoma was marked by an ischemic event after the initial episode, resulting in an aggravation of deficits. The cause of this second event was uncertain. Because our knowledge about the natural history of LSA aneurysms is incomplete, there is no consensus concerning a therapeutic strategy. The authors' experience in 3 reported cases leads them to think that a conservative approach involving close angiographic monitoring may be proposed as first-line treatment. If the monitored aneurysm then persists or grows in size, its occlusion should be considered. Nonetheless, other studies are needed to further strengthen the legitimacy of this strategy. PMID:24053505

Heck, Olivier; Anxionnat, Ren; Lacour, Jean-Christophe; Derelle, Anne-Laure; Ducrocq, Xavier; Richard, S閎astien; Bracard, Serge

2014-02-01

153

Simplified approach for design of raft foundations against fault rupture. Part II: soil-structure interaction  

NASA Astrophysics Data System (ADS)

This is the second paper of two, which describe the results of an integrated research effort to develop a four-step simplified approach for design of raft foundations against dip-slip (normal and thrust) fault rupture. The first two steps dealing with fault rupture propagation in the free-field were presented in the companion paper. This paper develops an approximate analytical method to analyze soil-foundation-structure interaction (SFSI), involving two additional phenomena: (i) fault rupture diversion (Step 3); and (ii) modification of the vertical displacement profile (Step 4). For the first phenomenon (Step 3), an approximate energy-based approach is developed to estimate the diversion of a fault rupture due to presence of a raft foundation. The normalized critical load for complete diversion is shown to be a function of soil strength, coefficient of earth pressure at rest, bedrock depth, and the horizontal position of the foundation relative to the outcropping fault rupture. For the second phenomenon (Step 4), a heuristic approach is proposed, which 搒cans through possible equilibrium positions to detect the one that best satisfies force and moment equilibrium. Thus, we account for the strong geometric nonlinearities that govern this interaction, such as uplifting and second order ( P-?) effects. Comparisons with centrifuge-validated finite element analyses demonstrate the efficacy of the method. Its simplicity makes possible its utilization for preliminary design.

Anastasopoulos, I.; Gerolymos, N.; Gazetas, G.; Bransby, M. F.

2008-06-01

154

Ruptured uterus: an ongoing tragedy of motherhood.  

PubMed

This study aimed to determine the frequency of ruptured uterus, possible aetiologic factors, foetomaternal out come and changes in obstetric care proposed to reduce this catastrophy. From September 1994 to September 1999 in Dhaka Medical College Hospital 39,782 deliveries occurred. All delivery records were reviewed and rupture uterus cases were identified. The result was compared with studies carried out in home and abroad. During the five years period among 39,782 deliveries 424 cases were of rupture uterus with a frequency of 1/93 deliveries. Eighty three percent rupture occurred in intact uterus and 17% occurred in uteri scarred by caesarian section. Common contributing factors were -prolonged/obstructed labour, grand multiparity, injudicious use of uterine stimulants, mismanaged labour by traditional birth attendant, delayed referral to well equipped centre, poor communication, poverty and ignorance. PMID:11942487

Khanam, R A; Khatun, M

2001-08-01

155

Supershear Rupture Propagation in Homogeneous, Monolithic Media: Experimental Observations  

Microsoft Academic Search

The rupture speeds obtained by fracture experiments of monolithic brittle materials are usually by far lower than those predicted by theories and inferred from inversions of seismograms: Some seismic inversions even suggest the existence of supershear rupture speeds (i.e., rupture propagating faster than the relevant shear wave). Exceptionally, a few laboratory experiments of dynamic rupture on pre-cut interfaces do indicate

K. Uenishi

2006-01-01

156

Spontaneous rupture of tubal leiomyoma causing haemoperitoneum.  

PubMed

Leiomyomas are benign tumours that usually originate from the genital tract organs, particularly from the uterus. Spontaneous rupture of leiomyomas is a relatively rare condition. Herein, we report a 70 years old lady who was admitted through the emergency room with sudden abdominal pain. A ruptured mass originating from the fallopian tube, causing haemoperitoneum was revealed at laparotomy. Pathological examination revealed cellular leiomyoma. PMID:24906284

Ozkan, Zeynep; Gonen, Ayse Nur; Emir, Seyfi; Yazar, Fatih Mehmet; Gul, Evrim; Artas, Zeynep Dogan; Aslan, Ozgen; Artas, Hakan

2014-05-01

157

Successful management of postinfarction ventricular septal rupture  

PubMed Central

Ventricular septal rupture is a rare but devastating complication of acute myocardial infarction. Especially in patients with cardiogenic shock, right ventricular dysfunction or an inferior infarct mortality is very high. We present a case in which an 83-year-old patient survived rupture of the ventricular septum complicating an inferior myocardial infarction. Unlike most patients his haemodynamic status did not deteriorate and delayed elective surgical repair was carried out successfully. ImagesFigure 1Figure 2

Swinkels, B.M.; Peters, R.H.J.; van den Brink, A.

2005-01-01

158

Transverse correlations in multiphoton entanglement  

SciTech Connect

We have analyzed the transverse correlation in multiphoton entanglement. The generalization of quantum ghost imaging is extended to the N-photon state. The Klyshko's two-photon advanced-wave picture is generalized to the N-photon case.

Wen Jianming; Rubin, Morton H.; Shih Yanhua [Physics Department, University of Maryland, Baltimore County, Baltimore, Maryland 21250 (United States)

2007-10-15

159

Gluon propagator and transverse vertices  

SciTech Connect

It is shown explicitly that in the axial gauge the Slavnov-Taylor identity contains no useful information for determining the gluon propagator through the Dyson-Schwinger equation; rather, it is the transverse vertex which plays the crucial role.

Zhang, R.B.

1985-03-15

160

Tensile stress rupture behavior of a woven ceramic matrix composite in humid environments at intermediate temperature  

NASA Astrophysics Data System (ADS)

This study focused on moisture and intermediate temperature effects on the embrittlement phenomenon and stress rupture life of the ceramic matrix composite (CMC) made of Sylramic(TM) fibers with an in-situ layer of boron nitride (Syl-iBN), boron nitride interphase (BN), and SiC matrix (Syl-iBN/BN/SiC). Stress rupture tests were performed at 550癈 or 750癈 with moisture contents of 0.0, 0.2, or 0.6 atm partial pressure of water vapor, pH 2O. The CMC stress rupture strengths at 100 hrs at 550癈 with 0.0, 0.2, or 0.6 atm pH2O were 75%, 65% and 51% of the monotonic room temperature tensile strength, respectively. At 750癈, the corresponding strengths were 67%, 51%, and 49%, respectively. Field Emission Scanning Electron Microscopy (FESEM) analysis showed that the amount of pesting by glass formations increased with time, temperature, and pH2O leading to embrittlement. Total embrittlement times for 550癈 were estimated to be greater than 63 hrs for 0.0 atm pH2O greater than 38 hrs for 0.2 atm pH 2O and between 8 and 71 hrs for 0.6 atm pH2O. Corresponding estimated embrittlement times for the 750癈 were greater than 83 hrs, between 13 and 71 hrs, and between 1 and 6 hrs. A time-dependent, phenomenological, Monte Carlo-type simulation of composite failure was developed. The simulated total embrittlement times for the 550癈 cases were 300 hrs, 100 hrs, and 25 hrs for 0.0, 0.2, and 0.6 atm pH 2O, respectively. The corresponding embrittlement times for the 750癈 cases were 300 hrs, 20 hrs, and 3 hrs. A detailed sensitivity analysis on the variables used in the model was conducted. The model was most sensitive to variation in the ultimate strength of the CMC at room temperature, the ultimate strength of the CMC at elevated temperature, and the reference strength of a fiber and it was least sensitive to variation in the modulus of elasticity of the matrix and fiber. The sensitivity analysis showed that the stress ruptures curves generated by variation in the total embrittlement time simulate the trends in the experimental data. This research showed that the degree of stress rupture strength degradation increases with temperature, moisture content level, and exposure time.

Larochelle, Kevin J.

161

Effect of rolling on the high temperature tensile and stress-rupture properties of tungsten fiber-superalloy composites  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the effects of mechanical working on the 1093 C (2000 F) tensile and stress-rupture strength of tungsten alloy/superalloy composites. Hot pressed composites containing either conventional tungsten lamp filament wire or tungsten-1% ThO2 wire and a nickel base alloy matrix were hot rolled at 1093 C (2000 F). The hot pressed and rolled composite specimens were then tested in tension and stress-rupture at 1093 C (2000 F). Rolling decreased the degree of fiber-matrix reaction as a function of time of exposure at 1093 C (2000 F). The stress-rupture properties of the rolled composites were superior to hot pressed composites containing equivalent diameter fibers. Rolling did not appreciably affect the 1093 C (2000 F) ultimate tensile strength of the composites.

Petrasek, D. W.

1974-01-01

162

Properties of inelastic yielding zones generated by in-plane dynamic ruptures桰I. Detailed parameter-space study  

NASA Astrophysics Data System (ADS)

We perform a detailed parameter-space study on properties of yielding zones generated by 2-D in-plane dynamic ruptures on a planar fault with different friction laws and parameters, different initial stress conditions, different rock cohesion values, and different contrasts of elasticity and mass density across the fault. The focus is on cases corresponding to large strike-slip faults having high angle (?) to the maximum compressive background stress. The simulations and analytical scaling results show that for crack-like ruptures (1) the maximum yielding zone thickness Tmax linearly increases with rupture distance L and the ratio Tmax/L is inversely proportional to (1 +S)2 with S being the relative strength parameter; (2) the potency density ? decays logarithmically with fault normal distance at a rate depending on the stress state and S; (3) increasing rock cohesion reduces Tmax/L, resulting in faster rupture speed and higher inclination angle ? of expected microfractures on the extensional side of the fault. For slip pulses in quasi-steady state, T is approximately constant along strike with local values correlating with the maximum slip velocity (or final slip) at a location. For a bimaterial interface with ?, the energy dissipation to yielding contributes to developing macroscopically asymmetric rupture (at the scale of rupture length) with the same preferred propagation direction predicted for purely elastic cases with Coulomb friction. When ?, representative for thrust faulting, the energy dissipation to yielding leads to opposite preferred rupture propagation. In all cases, ? is higher on average on the compliant side. For both crack and pulse ruptures with ?, T decreases and ? increases for conditions representing greater depth. Significant damage asymmetry of the type observed across several large strike-slip faults likely implies persistent macroscopic rupture asymmetry (unilateral cracks, unilateral pulses or asymmetric bilateral pulses). The results on various features of yielding zones expected from this and other studies are summarized in a table along with observations from the field and laboratory experiments.

Xu, Shiqing; Ben-Zion, Yehuda; Ampuero, Jean-Paul

2012-12-01

163

Comptes Rendus des JNC 16 Toulouse 2009 Critre de rupture en compression dans le sens des fibres du pli  

E-print Network

direction with structural effects J.C. Grandidier 1 , P. Casari 2 1 : Laboratoire de M茅canique et Physique type microflambage qui g茅n猫re une bande de cisaillement et conduit 脿 la rupture brutale des fibres sous strength is no more an intrinsic material property. In this paper, the so-called structure effect

Paris-Sud XI, Universit茅 de

164

Creep-rupture tests of internally pressurized Hastelloy-X tubes  

NASA Technical Reports Server (NTRS)

Seamless Hastelloy-X tubes with 0.375-in. outside diameter and 0.025-in. wall thickness were tested to failure at temperatures from 1400 to 1650 F and internal helium pressures from 800 to 1800 psi. Lifetimes ranged from 58 to 3600 hr. The creep-rupture strength of the tubes was from 20 to 40 percent lower than that of sheet specimens. Larson-Miller correlations and photomicrographs of some specimens are presented.

Gumto, K. H.; Colantino, G. J.

1973-01-01

165

Blood Chemical Abnormalities in Cattle with Ruptured Bladders and Ruptured Urethras  

PubMed Central

A study was undertaken to determine the blood chemical variables and compare changes that occurred with ruptured bladders and ruptured urethras in steers and yearling bulls. The fatality rates were 10.5% in steers with ruptured urethras and 50.8% in steers with ruptured bladders. Both groups had significantly decreased serum sodium and chloride values and significantly increased serum creatinine, blood urea nitrogen, and plasma protein concentrations compared to the normal group. Steers with ruptured bladders were more dehydrated, had significantly lower serum sodium and chloride values and had significantly higher blood urea nitrogen concentrations than steers with ruptured urethras. The combination of a decreased serum sodium, a decreased serum chloride, and a decreased ratio of serum phosphate to blood urea nitrogen occurred consistently within the ruptured bladder group. Of the variables examined, serum phosphate was the best prognostic indicator in the steers with ruptured bladders as all of the steers that died had a serum phosphate in excess of 2.9 mmol/L. The fluid and electrolyte changes are discussed. PMID:17422206

Donecker, J. M.; Bellamy, J. E. C.

1982-01-01

166

Dynamic rupture simulation with an experimentally-determined friction law leads to slip-pulse propagation  

NASA Astrophysics Data System (ADS)

We simulate the dynamic rupture along a vertical, strike-slip fault in an elastic half-space. The fault has frictional properties that were determined in high-velocity, rotary shear apparatus Sierra-White granite. The experimental fault was abruptly loaded by a massive flywheel, which is assumed to simulate the loading of a fault patch during an earthquake, and termed Earthquake-Like-Slip Event (ELSE) (Chang et al., 2012). The experiments revealed systematic alteration between slip-weakening and slip-strengthening (Fig. 1A), and were considered as proxies of fault-patch behavior during earthquakes of M = 4-8. We used the friction-distance relations of these experiments to form an empirical slip-dependent friction model, ELSE-model (Fig. 1B). For the dynamic rupture simulation, we used the program of Ampuero (2002) (2D spectral boundary integral elements) designed for anti-plane (mode III) shear fracturing. To compare with published works, the calculations used a crust with mechanical properties and stress state of Version 3 benchmark of SCEC (Harris et al., 2004). The calculations with a fault of ELSE-model friction revealed: (1) Rupture propagation in a slip-pulse style with slip cessation behind the pulse; (2) Systematic decrease of slip distance away from the nucleation zone; and (3) Spontaneous arrest of the dynamic rupture without a barrier. These features suggest a rupture of a self-healing slip-pulse mode (Fig. 1C), in contrast to rupturing of a fault with linear slip-weakening friction (Fig. 1B) (Rojas et al., 2008) in crack-like mode and no spontaneous arrest. We deduce that the slip-pulse in our simulation results from the fast recovery of shear strength as observed in ELSE experiments, and argue that incorporating this experimentally-based friction model to rupture modeling produces realistic propagation style of earthquake rupture. Figure 1 Fault patch behavior during an earthquake. (A) Experimental evolution of frictional stress, slip velocity, and displacement in ELSE (Chang et al., 2012). (B) Friction laws of ELSE-model and linear slip-weakening model. (C) Conceptual evolution of shear stress, slip velocity and displacement during a slip-pulse rupture (adapted from Heaton, 1990).

Liao, Z.; Chang, J. C.; Reches, Z.

2013-12-01

167

Jumping Rupture Dependence on Friction Formulations at Strike-Slip Fault Stepovers  

NASA Astrophysics Data System (ADS)

It is well known that fault stepovers can under some circumstances allow through-going rupture, and under other circumstances cause rupture termination (e.g., Harris and Day 1993; Kase and Kuge, 1998; Duan and Oglesby, 2006). However, the effects of different friction law formulations on jumping rupture have not been extensively explored. In this study we investigate how 4 different frictional parameterizations affect the ability of rupture to jump a stepover. We compare linear slip weakening friction (Ida, 1972) and 3 forms of rate- and state-dependent friction (Dieterich, 1978, 1979; Ruina, 1983): ageing law, slip law, and slip law with strong rate-weakening (e.g., Rice, 1999, 2006; Beeler and Tullis, 2003; Rojas et al., 2009). We use the dynamic finite element method (Barall, 2008) to model earthquake rupture along 2-D strike-slip stepovers, in both extensional and compressional settings. We have found that for parameterizations with the same effective slip-weakening distance, the functional form of the friction law can greatly effect whether or not rupture is likely to jump and continue along the secondary fault segment. In particular, we find that the slip law, which has lower fracture energy for a given effective slip-weakening distance than the aging law or the linear slip-weakening law, allows rupture to jump larger stepover widths than the aging or slip-weakening law. We also investigate the effect of the Linker-Dieterich (Linker and Dieterich, 1992) dependence of state variable on normal stress. We find through preliminary models that adding normal stress dependence to the state variable delays nucleation on the secondary fault segment when compared to normal-stress independent state evolution laws. Nucleations along the secondary segments occur in areas of decreased normal stress, in both compressional and dilational stepovers. However, state-variable dependent normal stress results in an increase in state variable (fault strength) in those same areas, thereby hindering rupture. Thus, we illustrate that the ability of rupture to jump a stepover can depend strongly on the formulation of the friction law. In the future we will investigate the effects of friction law formulation on other fault geometries including dip-slip faults.

Ryan, K. J.; Oglesby, D. D.

2011-12-01

168

Recurrence Characteristics of 'Full Rupture' Earthquakes  

NASA Astrophysics Data System (ADS)

A prime goal in earthquake geology is to identify the recurrence characteristics of full rupture earthquakes (earthquakes that rupture the full down-dip extend of the seismogenic zone and potentially beyond it) along a given fault. Paleoseismology and tectonic geomorphology enable to extend the seismic record by centuries or millennia --for events that are sufficiently large to disrupt the earth surface. Unfortunately, long records are rare and it is generally difficult to make statistically meaningful statements on recurrence characteristics. Furthermore, the paleoseismic and geomorphic records may also contain partial rupture earthquakes (events that may rupture ground surface but do not activate the full seismogenic width) and by that the masking signal of the full rupture events (as I will show in my presentation, those partial rupture events exhibit different recurrence characteristics than the full rupture events). Physics-based earthquake simulators provide the means to study the long-term behavior of a (simulated) fault with respect to the implemented boundary conditions (e.g., fault geometry, loading conditions, frictional behavior). Here, I present a numerical study on earthquake recurrence characteristics as a function of fault geometric roughness (considered a proxy for fault maturity) and by that as a function of fault interaction and connectivity. Focus was on magnitude-frequency distribution and fault segmentation as a function of roughness. I find that bimodality in magnitude frequency relation --the largest earthquakes occurring more frequently than anticipated from the Gutenberg-Richter relation-- is tightly linked to the structural maturity of a fault. Bimodal seismic behavior and maximum earthquake size increases as fault roughness decreases. Furthermore, the variability of large earthquake rupture characteristics of a given fault decreases with structural maturation and major earthquakes along spatially isolated faults exhibit inherent periodicity. While slip at a point along a fault is variable per se, variability becomes increasingly systematic as the fault matures. Based on my results and supported by paleoseismic data, I propose that previously presented earthquake recurrence models (uniform slip-, and characteristic earthquake model) generalize the seismic behavior of faults with different structural age and fault-system complexity and are characterized by alternating single-segment and multi-segment rupture probability.

Zielke, O.

2013-12-01

169

Caring for people with carotid artery rupture.  

PubMed

In the second of three articles, the authors discuss the care of people with carotid artery rupture. Carotid artery rupture is a potentially fatal condition that requires swift action on the part of the nurse who is present. The size of the rupture and the prognosis for the individual patient determines whether or not active resuscitation is undertaken. The multi-professional team should decide, in advance of an impending rupture, on the optimum plan of care. Calm, careful explanations should be given to patients and relatives and the decision regarding resuscitation should be recorded in the patient's notes. In the event of unforeseen circumstances where a rupture occurs, an active nursing care plan should be instituted and care taken to keep relatives well informed. The patient's airway should be kept clear through the use of suctioning, inflation of tracheostomy tube cuff and correct positioning. Sedative drugs and palliative care may subsequently be necessary. Support and help should be given to all who witness or are involved in the care of these patients. PMID:16415744

Frawley, Theresa; Begley, Cecily M

170

[Traumatic rupture of the corpus cavernosum].  

PubMed

Traumatic rupture of the corpus cavernosum is relatively frequent in the authors' experience. Based on the study of a series of 80 cases and a review of the literature, the authors analyse the diagnostic and therapeutic aspects and outcome of this disease. The patients in this series had a mean age of 30 years. Meticulous and intimate clinical interview demonstrated that the commonest mechanism is forced manipulation of the erect penis (68%). Clinical examination localized the site of the fracture (proximal: 57%, distal 43%). The fracture was unilateral (78 cases), rarely bilateral (2 cases) and associated with complete rupture of the urethra (1 case). Treatment was surgical in 79 patients. A distal semicircumferential incision was used in the case of bilateral rupture, distal rupture and associated urethral lesion (34 cases). A favourable course was observed in 86% of cases. However, 9 postoperative complications (12.5%) were observed (6 cases of fibrous plaques, 3 cases of chordee of the penis), due either to the extent of the haematoma or to the delay in treatment. Traumatic rupture of the corpus cavernosum is a disease of young adults, which requires early surgical treatment with an approach adapted to the type of lesions. PMID:9834519

Bennani, S; Dakir, M; Debbagh, A; Hafiani, M; el Moussaoui, A; el Mrini, M; Benjelloun, S

1998-09-01

171

Transverse wakefields at high dispersion  

SciTech Connect

In high energy linear colliders the transverse beam emittance has to be preserved in order to achieve small interaction spots. If the beam is off-center in an accelerating cavity, it excites transverse wakefields, mainly the dipole mode, which deflects the tail of the beam leading to an emittance growth. In a high dispersive region, even a well centered beam can excite wakefields of higher order modes since the energy spread of the beam causes a transverse beam size which is comparable with the beam pipe. During the bunch length compression in the ring-to-linac (RTL) section of the Stanford Linear Collider (SLC), the beam pipe of 75 mm diameter is practically filled in the horizontal plane. Especially, if beam losses start to be involved, the very outer parts of the beam excite wakefields at any pipe irregularities like bellows, diameter steps, etc. Measured evidences, theoretical estimates and comparisons to other effects, like higher order magnet optics, are presented.

Decker, F.J.

1992-03-01

172

Flutter analysis using transversality theory  

NASA Technical Reports Server (NTRS)

A new method of calculating flutter boundaries of undamped aeronautical structures is presented. The method is an application of the weak transversality theorem used in catastrophe theory. In the first instance, the flutter problem is cast in matrix form using a frequency domain method, leading to an eigenvalue matrix. The characteristic polynomial resulting from this matrix usually has a smooth dependence on the system's parameters. As these parameters change with operating conditions, certain critical values are reached at which flutter sets in. Our approach is to use the transversality theorem in locating such flutter boundaries using this criterion: at a flutter boundary, the characteristic polynomial does not intersect the axis of the abscissa transversally. Formulas for computing the flutter boundaries and flutter frequencies of structures with two degrees of freedom are presented, and extension to multi-degree of freedom systems is indicated. The formulas have obvious applications in, for instance, problems of panel flutter at supersonic Mach numbers.

Afolabi, D.

1993-01-01

173

Pseudoscalar Meson Electroproduction and Transversity  

SciTech Connect

Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged boson limit can be described by generalized parton distributions (GPDs). Including spin dependence in the description requires 8 independent quark-parton and gluon-parton functions. The chiral even subset of 4 quark-nucleon GPDs are related to nucleon form factors and to parton distribution functions. The chiral odd set of 4 quark-nucleon GPDs are related to transversity, the tensor charge, and other quantities related to transversity. Different meson or photon production processes access different combinations of GPDs. This is analyzed in terms of t-channel exchange quantum numbers, JPC and it is shown that pseudoscalar production can isolate chiral odd GPDs. There is a sensitive dependence in various cross sections and asymmetries on the tensor charge of the nucleon and other transversity parameters. In a second section, analyticity and completeness are shown to limit the partonic interpret ation of the GPDs in the ERBL region.

Gary Goldstein, Simonetta Liuti

2011-05-01

174

Pseudoscalar Meson Electroproduction and Transversity  

NASA Astrophysics Data System (ADS)

Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged boson limit can be described by generalized parton distributions (GPDs). Including spin dependence in the description requires 8 independent quark-parton and gluon-parton functions. The chiral even subset of 4 quark-nucleon GPDs are related to nucleon form factors and to parton distribution functions. The chiral odd set of 4 quark-nucleon GPDs are related to transversity, the tensor charge, and other quantities related to transversity. Different meson or photon production processes access different combinations of GPDs. This is analyzed in terms of t-channel exchange quantum numbers, JPC and it is shown that pseudoscalar production can isolate chiral odd GPDs. There is a sensitive dependence in various cross sections and asymmetries on the tensor charge of the nucleon and other transversity parameters. In a second section, analyticity and completeness are shown to limit the partonic interpret ation of the GPDs in the ERBL region.

Goldstein, Gary R.; Liuti, Simonetta

2011-02-01

175

Hitherto unknown shear rupture mechanism as a source of instability in intact hard rocks at highly confined compression  

NASA Astrophysics Data System (ADS)

Today, frictional shear resistance along pre-existing faults is considered to be the lower limit on rock shear strength for confined conditions corresponding to the seismogenic layer. This paper introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. In the new mechanism, the rock failure associated with consecutive creation of small slabs (known as 慸omino-blocks') from the intact rock in the rupture tip is driven by a fan-shaped domino structure representing the rupture head. The fan-head combines such unique features as: extremely low shear resistance, self-sustaining stress intensification, and self-unbalancing conditions. Due to this the failure process caused by the mechanism is very dynamic and violent. This makes it impossible to directly observe and study the mechanism and can explain why the mechanism has not been detected before. This paper provides physical motivation for the mechanism, based upon side effects accompanying the failure process. Physical and mathematical models of the mechanism presented in the paper explain unique and paradoxical features of the mechanism. The new shear rupture mechanism allows a novel point of view for understanding the nature of spontaneous failure processes in hard rocks including earthquakes.

Tarasov, Boris G.

2014-05-01

176

Large-Scale Weibull Analysis of H-451 Nuclear- Grade Graphite Specimen Rupture Data  

NASA Technical Reports Server (NTRS)

A Weibull analysis was performed of the strength distribution and size effects for 2000 specimens of H-451 nuclear-grade graphite. The data, generated elsewhere, measured the tensile and four-point-flexure room-temperature rupture strength of specimens excised from a single extruded graphite log. Strength variation was compared with specimen location, size, and orientation relative to the parent body. In our study, data were progressively and extensively pooled into larger data sets to discriminate overall trends from local variations and to investigate the strength distribution. The CARES/Life and WeibPar codes were used to investigate issues regarding the size effect, Weibull parameter consistency, and nonlinear stress-strain response. Overall, the Weibull distribution described the behavior of the pooled data very well. However, the issue regarding the smaller-than-expected size effect remained. This exercise illustrated that a conservative approach using a two-parameter Weibull distribution is best for designing graphite components with low probability of failure for the in-core structures in the proposed Generation IV (Gen IV) high-temperature gas-cooled nuclear reactors. This exercise also demonstrated the continuing need to better understand the mechanisms driving stochastic strength response. Extensive appendixes are provided with this report to show all aspects of the rupture data and analytical results.

Nemeth, Noel N.; Walker, Andrew; Baker, Eric H.; Murthy, Pappu L.; Bratton, Robert L.

2012-01-01

177

Component external leakage and rupture frequency estimates  

SciTech Connect

In order to perform detailed internal flooding risk analyses of nuclear power plants, external leakage and rupture frequencies are needed for various types of components - piping, valves, pumps, flanges, and others. However, there appears to be no up-to-date, comprehensive source for such frequency estimates. This report attempts to fill that void. Based on a comprehensive search of Licensee Event Reports (LERs) contained in Nuclear Power Experience (NPE), and estimates of component populations and exposure times, component external leakage and rupture frequencies were generated. The remainder of this report covers the specifies of the NPE search for external leakage and rupture events, analysis of the data, a comparison with frequency estimates from other sources, and a discussion of the results.

Eide, S.A.; Khericha, S.T.; Calley, M.B.; Johnson, D.A.; Marteeny, M.L.

1991-11-01

178

Anterior Cruciate Ligament Rupture and Osteoarthritis Progression  

PubMed Central

Anterior Cruciate Ligament (ACL) rupture is a common sporting injury that frequently affects young, athletic patients. Apart from the functional problems of instability, patients with ACL deficient knees also develop osteoarthritis. Although this is frequently cited as an indication for ACL reconstruction, the relationship between ACL rupture, reconstruction and the instigation and progression of articular cartilage degenerative change is controversial. The purpose of this paper is to review the published literature with regards ACL rupture and the multifactorial causes for osteoarthritis progression, and whether or not this is slowed or stopped by ACL reconstruction. There is no evidence in the published literature to support the view that ACL reconstruction prevents osteoarthritis, although it may prevent further meniscal damage. It must be recognised that this conclusion is based on the current literature which has substantial methodological limitations. PMID:22896777

Wong, James Min-Leong; Khan, Tanvir; Jayadev, Chethan S; Khan, Wasim; Johnstone, David

2012-01-01

179

Acoustic levels of heavy truck tire ruptures.  

PubMed

Transportation vehicles, whether they are passenger vehicles or heavy trucks and transport vehicles, rely upon rubber tires to negotiate the roadways and surfaces on which they are driven. These tires have the potential of sudden rupture resulting from various causes including but not limited to over-pressurization, sidewall failures, or punctures from roadway debris. These rupture events can and do occur while the vehicles are stationary (e.g., during servicing) or are being driven, and often occur without notice. While the phenomenon of sudden tire failure has been documented for several decades, the potential bodily injury which can occur when an individual is in close proximity to such a sudden rupture has only more recently been documented. Aside from anecdotal mention in case studies, there has been little quantitative information available on the acoustic levels during these failures. Our study provides measured acoustic levels as a function of distance for such catastrophic tire failures. PMID:23622472

Wood, Matthew; Woodruff, William

2013-05-01

180

Ruptured venous aneurysm of cervicomedullary junction  

PubMed Central

Background: Ruptured venous aneurysm is often seen with arterio-venous malformation (AVM) or developmental venous anomaly (DVA). However, isolated venous aneurysm is unusual. Case Description: We present a case of ruptured venous aneurysm that presented with subarachnoid hemorrhage (SAH) and intraventricular hemorrhage (IVH). Digital substraction angiography (DSA) revealed a saccular contrast filling pouch in the left lateral aspect of cervicomedullary junction (CMJ). Endovascular intervention was not a viable option. During surgery, a saccular pliable structure approx. 1.5 1 cm was found in the subarachnoid space that was clipped and excised. There were no arterial feeders, no evidence of surrounding AVM, and no dilated perimedullary vein. Conclusion: This is perhaps the first reported case of ruptured venous aneurysm (without associated AVM) of CMJ, which was successfully managed surgically. The possible etiologies remain an unnoticed head trauma or a congenital vessel wall abnormality. Surgically clipping and excision remains the treatment of choice for such lesion. PMID:24575317

Aggarwal, Ashish; Salunke, Pravin; Futane, Sameer; Mathuriya, S. N.; Kumar, Ajay; Mukherjee, K. K.; Radotra, B. D.

2014-01-01

181

Mechanical properties of high-strength concrete  

NASA Astrophysics Data System (ADS)

This report summarizes an experimental program conducted to investigate production techniques and mechanical properties of high strength concrete in general and to provide recommendations for using these concretes in manufacturing precast/prestressed bridge girders. Test variables included total amount and composition of cementitious material (portland cement, fly ash, and silica fume), type and brand of cement, type of silica fume (dry densified and slurry), type and brand of high-range water-reducing admixture, type of aggregate, aggregate gradation, maximum aggregate size, and curing. Tests were conducted to determine the effects of these variables on changes in compressive strength and modulus of elasticity over time, splitting tensile strength, modulus of rupture, creep, shrinkage, and absorption potential (as an indirect indicator of permeability). Also investigated were the effects of test parameters such as mold size, mold material, and end condition. Over 6,300 specimens were cast from approximately 140 mixes over a period of 3 years.

Mokhtarzadeh, Alireza

182

Realizing vector meson dominance with transverse charge densities  

SciTech Connect

The transverse charge density in a fast-moving nucleon is represented as a dispersion integral of the imaginary part of the Dirac form factor in the timelike region (spectral function). At a given transverse distance b the integration effectively extends over energies in a range {radical}t {approx}< 1/b, with exponential suppression of larger values. The transverse charge density at peripheral distances thus acts as a low-pass filter for the spectral function and allows one to select energy regions dominated by specific t-channel states, corresponding to definite exchange mechanisms in the spacelike form factor. We show that distances b {approx} 0.5 - 1.5 fm in the isovector density are maximally sensitive to the {rho} meson region, with only a {approx}10% contribution from higher-mass states. Soft-pion exchange governed by chiral dynamics becomes relevant only at larger distances. In the isoscalar density higher-mass states beyond the {omega} are comparatively more important. The dispersion approach suggests that the positive transverse charge density in the neutron at b {approx} 1 fm, found previously in a Fourier analysis of spacelike form factor data, could serve as a sensitive test of the isoscalar strength in the {approx}1 GeV mass region. In terms of partonic structure, the transverse densities in the vector meson region b {approx} 1 fm support an approximate mean-field picture of the motion of valence quarks in the nucleon.

Gerald Miller, Mark Strikman, Christian Weiss

2011-10-01

183

The effect of transient overloads on the stress-rupture of glass fibre reinforced polymers  

NASA Astrophysics Data System (ADS)

Power station cooling water (CW) system components may be subject to water hammer events during their thirty year service life. The immediate and long term effects of such events on glass fibre reinforced polymer (GFRP) structures were hitherto unknown. This study investigates these effects and considers how well design codes address the problem of water hammer. A sequence of model water hammer events were applied to coupons of glass reinforced polyester and vinyl ester laminates ("overloaded" coupons). Damage studies revealed transverse resin cracking but no fibre fractures. The effect of stress/time profile on damage was investigated. CW systems operating from a constant head reservoir were modelled by stress-rupture tests in an aqueous environment at 40 C. Stress-rupture lifetime of overloaded coupons was found to be reduced in comparison to virgin coupons. CW systems operating from a coastal reservoir were simulated by applying a sinusoidal load regime, with an R-ratio of 0.67, at a frequency of 23.15 Hz, to overloaded coupons in an aqueous environment at 40 C. The results were then compared with those from the stress-rupture tests. Genuine water hammer events were also applied to a model component. Glass reinforced polyester pipes of 151mm diameter were subjected to ten water hammer events of the type occurring in a CW system ("overloaded" pipes). Axial cracking resulted. Stress-rupture testing was carried out on virgin and overloaded pipes in an aqueous environment at 40 C. The lifetime of overloaded pipes was reduced in comparison to virgin pipes. This was attributed to enhanced stress-corrosion cracking at sites of water hammer induced cracking.Stress-rupture results for material tested in pipe and coupon form were compared. At a given stress level, longer lifetimes were exhibited by pipe material. This indicated that designing from coupon data might lead to costly overdesign. Design codes were then reviewed in the light of the above experimental results.

Rawles, J. D.

184

Time/Temperature Dependent Tensile Strength of SiC and Al2O3-Based Fibers  

NASA Technical Reports Server (NTRS)

In order to understand and model the thermomechanical behavior of fiber-reinforced composites, stress-rupture, fast-fracture, and warm-up rupture studies were conducted on various advanced SiC and Al2O3-based fibers in the,temperature range from 20 to 1400 C in air as well as in inert environments. The measured stress-rupture, fast fracture, and warm-up rupture strengths were correlated into a single master time/temperature-dependent strength plot for each fiber type using thermal activation and slow crack growth theories. It is shown that these plots are useful for comparing and selecting fibers for CMC and MMC reinforcement and that, in comparison to stress rupture tests, the fast-fracture and warm-up tests can be used for rapid generation of these plots.

Yun, Hee Mann; DiCarlo, James A.

1997-01-01

185

Missing transverse energy significance at CMS  

E-print Network

Missing transverse energy significance may be used to help distinguish real missing transverse energy due to undetected particles from spurious missing transverse energy due to resolution smearing. We present a description of the missing transverse energy significance variable, and assess its performance in Z$\\rightarrow\\mu\\mu$, dijet, and W$\\rightarrow e\

Nathan Mirman; Yimin Wang; James Alexander

2014-09-10

186

[Characteristics of duodenal ruptures depending on topographical and anatomical properties of this organ and circumstances of blunt abdominal trauma].  

PubMed

We have studied specific morphological properties of duodenal rupture depending on the topographic and anatomical features of this organ and circumstances of blunt abdominal trauma suffered in a car crash (with the victim found in the passenger compartment or involved in an automobile-pedestrian accident) and a railway crash (a train-pedestrian accident) or resulting from a blunt-force trauma, a fall from height, a fall on the stomach, and traumatic compression of the body. We took into consideration the anatomical peculiarities of the duodenal rupture, such as its circular, horseshoe, and loop-like shape. The study has demonstrated that the frequency of duodenal injury associated with a blunt abdominal trauma shows a stronger dependence on the topographical and anatomical peculiarities of duodenum than on the circumstances of the case. Specifically, the circular duodenum and especially its descending portion are more readily subjected to the damage than the organs of a different shape. The position of the break with respect to the duodenal axis is an important diagnostic signs allowing to clarify circumstances of the blunt injury. Transverse ruptures are typical of strong impacts associated with the short-term interaction between the damaging object and the affected part of the body whereas longitudinal ruptures more commonly occur as a result the long-term traumatic impact. Bile imbibition of paraduodenal and peripancreatic retroperitoneal adipose tissue may be used as an additional diagnostic sign of duodenal rupture. PMID:24428049

Pigolkin, Iu I; Dubrovin, I A; Chirkov, R N; Dubrovina, I A; Khachaturian, B S; Mosoian, A S; Dallakian, V F

2013-01-01

187

Transverse Polarisation of Quarks in Hadrons  

E-print Network

We review the present state of knowledge regarding the transverse polarisation (or transversity) distributions of quarks. After some generalities on transverse polarisation, we formally define the transversity distributions within the framework of a classification of all leading-twist distribution functions. We describe the QCD evolution of transversity at leading and next-to-leading order. A comprehensive treatment of non-perturbative calculations of transversity distributions (within the framework of quark models, lattice QCD and QCD sum rules) is presented. The phenomenology of transversity (in particular, in Drell-Yan processes and semi-inclusive leptoproduction) is discussed in some detail. Finally, the prospects for future measurements are outlined.

Barone, V; Ratcliffe, P G; Barone, Vincenzo; Drago, Alessandro; Ratcliffe, Philip G.

2002-01-01

188

Myocardial Rupture following Carbon Monoxide Poisoning  

PubMed Central

We present the first case of severe cardiotoxicity of carbon monoxide leading to myocardial rupture and fatal outcome. 83-year-old woman was hospitalized 4 hours after the fire in her house with no respiratory or cardiac symptoms. After two days, she has suffered sudden collapse leading to cardiac arrest. Postmortem examination revealed intramural haemorrhage with myocardial rupture at the apex of the left ventricle. Minimal stenosis was noted in the proximal coronary arteries with no evidence of distal occlusion or any other long-standing heart disease. This case supports recommendations for targeted cardiovascular investigations in cases of CO poisoning. PMID:25110594

Dragelyte, Gabija; Plenta, Juris; Chmieliauskas, Sigitas; Jasulaitis, Algimantas; Raudys, Romas; Jovaisa, Tomas; Badaras, Robertas

2014-01-01

189

[Apophyseal rupture of ischial bone tuberosity].  

PubMed

The apophyses of the pelvic skeleton are the insertion zones of strong muscles and tendons and are soft points towards the end of growth. Apophyseal ruptures have quite often occurred as a consequence of overstressing in the context of certain athletic disciplines. Reported in this paper are two of the authors' own cases of apophyseal rupture of Tuber ossis ischii. Diagnosis is easy on the basis of case history, clinical manifestations, and X-ray. Treatment is conservative, with the patient hip-straightened confined to bed for three weeks. Surgery might be indicated in cases of continued seating problems or neurological failures. PMID:3577444

Lindner, H O; Winkeltau, G; Kalemba, J

1987-01-01

190

New transverse damper correction scheme  

SciTech Connect

A transverse damping system for providing beam motion stability against Dipole Mode Multibunch Instabilities (DMMI) in the Superconducting Super Collider (SSC) is outlined. This damper makes use of two monitors and one kicker, as in existing designs. The novel feature is the use of a new correction scheme, which provides exact orbit compensation within two turns.

Lopez, G.

1993-10-01

191

Dihadron Fragmentation Functions and Transversity  

E-print Network

We present preliminary results for an updated extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. Data for proton and deuteron targets by HERMES and COMPASS allow for a flavor separation of the valence components of transversity, while di-hadron fragmentation functions are taken from the semi-inclusive production of two pion pairs in back-to-back jets in $e^+ e^-$ annihilation. The latter data from Belle have been reanalyzed using the replica method and a more realistic estimate of the uncertainties on the chiral-odd interference fragmentation function has been obtained. After encoding this piece of information into the deep-inelastic scattering cross section, the transversity has been re-extracted by using the most recent and more precise COMPASS data for proton target. This picture represents the current most realistic estimate of the uncertainties on our knowledge of tran...

Radici, Marco; Bacchetta, Alessandro

2014-01-01

192

Transverse halo orbits about Mars?  

Microsoft Academic Search

We predict a new family of charged dust rings about Mars, transverse to the ecliptic plane. These orbits are stable to the perturbations of planetary oblateness, Mars' orbital motion, and the solar wind. Lifetimes of individual orbits are limited primarily by the Lorentz force and Poynting-Robertson drag, and may exceed 1000 years. They may be populated via collisions of micrometeoroids

J. E. Howard; A. V. Krivov; F. Spahn

2003-01-01

193

Transverse Magnetic Field Propellant Isolator  

NASA Technical Reports Server (NTRS)

An alternative high voltage isolator for electric propulsion and ground-based ion source applications has been designed and tested. This design employs a transverse magnetic field that increases the breakdown voltage. The design can greatly enhance the operating range of laboratory isolators used for high voltage applications.

Foster, John E.

2000-01-01

194

Transverse structure of the nucleon  

NASA Astrophysics Data System (ADS)

In recent years parton distributions, describing longitudinal momentum, helicity and transversity distributions of quarks and gluons, have been generalized to account also for transverse degrees of freedom. Two new sets of more general distributions, Transverse Momentum Distributions (TMDs) and Generalized Parton Distributions (GPDs) were introduced to describe transverse momentum and space distributions of partons. Great progress has been made since then in measurements of different Single Spin Asymmetries (SSAs) in semi-inclusive and hard exclusive processes providing access to TMDs and GPDs respectively. Facilities world-wide involved in studies of the 3D structure of nucleon include HERMES at HERA, CLAS and Hall-A at JLab and COMPASS at CERN. TMD studies in Drell-Yan are also becoming an important part of the program of future facilities, such as JPARC, GSI and EIC. Significant progress has been achieved recently in lattice measurements of TMD moments. Studies of TMDs are also one of the main driving forces of the JLab 12 GeV upgrade project. In this talk we present an overview of the latest developments in studies of TMDs and discuss newly released results, ongoing activities, as well as some future measurements. )

Avakian, Harut

2010-02-01

195

Transverse Energy Production at RHIC  

E-print Network

We study the mechanism of transverse energy (E_T) production in Au+Au collisions at RHIC. The time evolution starting from the initial energy loss to the final E_T production is closely examined in transport models. The relationship between the experimentally measured E_T distribution and the maximum energy density achieved is discussed.

Qun Li; Yang Pang; Nu Xu

1999-06-18

196

Effects of Thermal Treatment on Tensile Creep and Stress-Rupture Behavior of Hi-Nicalon SiC Fibers  

NASA Technical Reports Server (NTRS)

Tensile creep and stress-rupture studies were conducted on Hi-Nicalon SiC fibers at 1200 and 1400 C in argon and air. Examined were as-received fibers as well as fibers annealed from 1400 to 1800 C for 1 hour in argon before testing. The creep and rupture results for these annealed fibers were compared to those of the as-received fibers to determine the effects of annealing temperature, test temperature, and test environment. Argon anneals up to 1500 C degrade room temperature strength of Hi-Nicalon fibers, but improve fiber creep resistance in argon or air by as much as 100% with no significant degradation in rupture strength. Argon anneals above 1500 C continue to improve fiber creep resistance when tested in argon, but significantly degrade creep resistance and rupture strength when tested in air. Decrease in creep resistance in air is greater at 1200 C than at 1400 C. Mechanisms are suggested for the observed behavior.

Yun, H. M.; Goldsby, J. C.; Dicarlo, J. A.

1995-01-01

197

Creep rupture of the joint of a solid oxide fuel cell glass-ceramic sealant with metallic interconnect  

NASA Astrophysics Data System (ADS)

Creep properties of sandwich joint specimens made of a newly developed BaO-B2O3-Al2O3-SiO2 glass-ceramic sealant (GC-9) and a ferritic-stainless-steel interconnect (Crofer 22 H) for planar solid oxide fuel cells (pSOFCs) are investigated at 800牥C under constant shear and tensile loadings. The creep rupture time of Crofer 22 H/GC-9/Crofer 22 H joint specimens is increased with a decrease in applied load for both shear and tensile loading modes. The given metal/sealant/metal joint has a greater degradation of joint strength at 800牥C under prolonged, constant tensile loading as compared to shear loading. The tensile creep strength at a rupture time of 1000爃 is about 9% of the average tensile joint strength, while the shear creep strength at 1000爃 is about 23% of the average shear joint strength. Failure patterns of both shear and tensile joint specimens are similar regardless of the creep rupture time. In general, creep cracks initiate at the interface between the (Cr,Mn)3O4 spinel layer and the BaCrO4 chromate layer, penetrate through the BaCrO4 layer, and propagate along the interface between the chromate layer and glass-ceramic substrate until final fracture. Final, fast fracture occasionally takes place within the glass-ceramic layer.

Lin, Chih-Kuang; Lin, Kun-Liang; Yeh, Jing-Hong; Wu, Si-Han; Lee, Ruey-Yi

2014-01-01

198

Strength and conductivity of unidirectional copper composites reinforced by continuous SiC fibers  

NASA Astrophysics Data System (ADS)

A SiC long fiber-reinforced copper composite offers a beneficial combination of high strength and high thermal conductivity at elevated temperatures. Both properties make the composite a promising material for the heat sink of high-heat-flux components. In this work, we developed a novel Cu/SiCf composite using the Sigma fiber. Based on HIP technique, a metallurgical process was established for fabricating high quality specimens using a TiC interface coating. Extensive tensile tests were conducted on the unidirectionally reinforced composite at 20 癈 and 300 癈 for a wide range of fiber volume fraction (Vf). In this paper, a large amount of test data is presented. The transversal thermal conductivity varies from 260 to 130 W/mK at 500 癈 as Vf is increased from 13% to 37%. The tensile strength reached up to 1246 MPa at 20 癈 for Vf = 37.6%, where the fracture strain was limited to 0.8%. The data of both elastic modulus and ultimate strength exhibited a good agreement with the rule-of-mixture predictions indicating a high quality of the materials. The strength of the composite with the Sigma fibers turned out to be superior to those of the SCS6 fibers at 300 癈, although the SCS6 fiber actually has a higher strength than the Sigma fiber. The fractographic pictures of tension test and fiber push-out test manifested a sufficient interfacial bonding. Unidirectional copper composite reinforced by long SiC fibers was fabricated using the Sigma SM1140+ fiber for a wide range of fiber volume fraction from 14% to 40%. Extensive tensile tests were carried out at RT and 300 癈. The data of ultimate strength as well as elastic modulus exhibited a good agreement with the rule-of-mixture predictions indicating a high quality of the materials. In terms of the tensile strength, the Cu/Sigma composite turned out to be superior to the previous Cu/SCS6 composite at 300 癈, while comparable at RT, although the SCS6 fiber has a higher strength than the Sigma fiber. Such a beneficial outcome of the Sigma fiber may be attributed to its smaller radius leading to a larger total interface area for a given fiber content. The fractographic images after tensile rupture and fiber push-out test manifested a solid interfacial bonding via the thin TiC film. The weakest site was identified to be the internal interface between the outer carbon coating and the inner SiC layer. Numerous voids were observed in the plastically ruptured matrix after tensile fracture. The density of the voids was larger at 300 癈 than RT. The distributed voids are the evidence of ductile damage affecting the plastic work of the composite.

Kimmig, S.; Allen, I.; You, J. H.

2013-09-01

199

Linker Dependent Bond Rupture Force Measurements in Single-Molecule Junctions  

SciTech Connect

We use a modified conducting atomic force microscope to simultaneously probe the conductance of a single-molecule junction and the force required to rupture the junction formed by alkanes terminated with four different chemical link groups which vary in binding strength and mechanism to the gold electrodes. Molecular junctions with amine, methylsulfide, and diphenylphosphine terminated molecules show clear conductance signatures and rupture at a force that is significantly smaller than the measured 1.4 nN force required to rupture the single-atomic gold contact. In contrast, measurements with a thiol terminated alkane which can bind covalently to the gold electrode show conductance and force features unlike those of the other molecules studied. Specifically, the strong Au-S bond can cause structural rearrangements in the electrodes, which are accompanied by substantial conductance changes. Despite the strong Au-S bond and the evidence for disruption of the Au structure, the experiments show that on average these junctions also rupture at a smaller force than that measured for pristine single-atom gold contacts.

Frei M.; Hybertsen M.; Aradhya S.V.; Venkataraman L.

2012-02-16

200

What Is an Earthquake?: Rupture Models  

NSDL National Science Digital Library

In this activity, the learner will watch three animations based on actual data from fault ruptures from the two largest Southern California earthquakes in the 1990s: Landers (1992) and Northridge (1994). In Section 3, the learner will discover more about how such data is collected and analyzed.

201

Laparoscopic splenectomy for atraumatic splenic rupture.  

PubMed

A traumatic splenic rupture (ASR) is a rare clinical entity. Several underlying benign and malignant conditions have been described as a leading cause. We report on a case of ASR in a 41-year-old man treated with laparoscopic splenectomy. Considering ASR as a life-threatening condition, a prompt diagnosis can be life saving. PMID:21675627

Grossi, Ugo; Crucitti, Antonio; D'Amato, Gerardo; Mazzari, Andrea; Tomaiuolo, Pasquina M C; Cavicchioni, Camillo; Bellantone, Rocco

2011-01-01

202

Postintubation Tracheal Ruptures - A case report -  

PubMed Central

Tracheobronchial ruptures (TBR) rarely complicate surgical procedures under general anesthesia. Seemingly uneventful intubations can result in injury to the trachea, which often manifests as hemoptysis and subcutaneous emphysema. We present 2 patients with postintubation TBR who were treated surgically and discuss considerations in the management of this potentially lethal injury. PMID:22263165

Kim, Kyung Hwa; Choi, Jong-Bum; Kuh, Ja-Hong; Jo, Jung-Ku; Park, Hyun Kyu

2011-01-01

203

Star polymers rupture induced by constant forces  

NASA Astrophysics Data System (ADS)

In this work, we study the breakage process of an unknotted three-arm star-shaped polymer when it is pulled from its free ends by a constant force. The star polymer configuration is described through an array of monomers coupled by anharmonic bonds, while the rupture process is tracked in three-dimensional space by means of Langevin Molecular Dynamics simulations. The interaction between monomers is described by a Morse potential, while a Weeks-Chandler-Anderson energetic contribution accounts for the excluded volume interaction. We explore the effect of the molecular architecture on the distributions of rupture times over a broad interval of pulling forces and star configurations. It was found that the rupture time distribution of the individual star arms is strongly affected by the star configuration imposed by the pulling forces and the length of the arms. We also observed that for large pulling forces the rupture time distributions resemble the dominant features observed for linear polymer chains. The model introduced here provides the basic ingredients to describe the effects of tensile forces on stress-induced degradation of branched macromolecules and polymer networks.

Garc韆, N. A.; Febbo, M.; Vega, D. A.; Milchev, A.

2014-10-01

204

Bond-rupture immunosensors--a review.  

PubMed

It has long been the goal of researchers to develop fast and reliable point-of-care alternatives to existing lab-based tests. A viable point-of-care biosensor is fast, reliable, simple, cost-effective, and detects low concentrations of the target analyte. The target of biosensors is biological such as bacteria or virus and as such, the antibody-antigen bond derived from the real immune response is used. Biosensor applications include lab-based tests for the purposes of diagnostics, drug discovery, and research. Additional applications include environmental, food, and agricultural monitoring. The main merits of the bond-rupture method are quick, simple, and capable of discriminating between specific and non-specific interactions. The separation of specific and non-specific bonds is important for working in real-life complex serums such as blood. The bond-rupture technique can provide both qualitative results, the detection of a target, and quantitative results, the concentration of target. Bond-rupture achieves this by a label-free method requiring no pre-processing of the analyte. A piezoelectric transducer such as the quartz crystal microbalance (QCM) shakes the bound particles free from the surface. Other transducers such as Surface Acoustic Wave (SAW) are also considered. The rupture of the bonds is detected as electronic noise. This review article links diverse research areas to build a picture of a field still in development. PMID:18343101

Hirst, Evan R; Yuan, Yong J; Xu, W L; Bronlund, J E

2008-07-15

205

Penile Fracture with Associated Urethral Rupture  

PubMed Central

Penile fracture of the erect penis is an uncommon but emergent urological trauma. Potential outcomes include erectile dysfunction, penile curvature, and urethral injury. Treatment is emergent surgical repair. We present the case of a 42-year-old man with a penile fracture complicated by a urethral rupture and subsequent repair. A discussion of the key aspects of this condition is presented. PMID:21076536

Boncher, Nicholas A.; Vricella, Gino J.; Jankowski, Jason T.; Ponsky, Lee E.; Cherullo, Edward E.

2010-01-01

206

Surface Rupture in Northwest Saudi Arabia  

USGS Multimedia Gallery

Wendy McCausland of the USGS Volcano Disaster Assistance Program and Hani Zahran of the Saudi Geological Survey view the southern end of the surface fault rupture caused by a M5.4 earthquake in the Saudi Arabian desert on May 19, 2009. The ground displacements in the soft sediments of the foreground...

2010-09-28

207

Unusual rupture of a flexor profundus tendon.  

PubMed

An unusual rupture of a flexor profundus tendon, previously unreported in the literature, is presented. There was avulsion and proximal displacement of a large bone fragment from the palmar base of the distal phalanx and further retraction of the tendon unattached to the bone fragment. PMID:3958452

Langa, V; Posner, M A

1986-03-01

208

Fault branching and rupture directivity Sonia Fliss  

E-print Network

, some understanding of the mechanics underlying dynamic processes of fault branching and jumping has earthquake from the rupture pattern it left? The answer to that question would be very useful for risk assessment of future earthquakes, even if it is cur- rently unknown if large earthquakes do systematically

Dmowska, Renata

209

Star polymers rupture induced by constant forces.  

PubMed

In this work, we study the breakage process of an unknotted three-arm star-shaped polymer when it is pulled from its free ends by a constant force. The star polymer configuration is described through an array of monomers coupled by anharmonic bonds, while the rupture process is tracked in three-dimensional space by means of Langevin Molecular Dynamics simulations. The interaction between monomers is described by a Morse potential, while a Weeks-Chandler-Anderson energetic contribution accounts for the excluded volume interaction. We explore the effect of the molecular architecture on the distributions of rupture times over a broad interval of pulling forces and star configurations. It was found that the rupture time distribution of the individual star arms is strongly affected by the star configuration imposed by the pulling forces and the length of the arms. We also observed that for large pulling forces the rupture time distributions resemble the dominant features observed for linear polymer chains. The model introduced here provides the basic ingredients to describe the effects of tensile forces on stress-induced degradation of branched macromolecules and polymer networks. PMID:25362341

Garc韆, N A; Febbo, M; Vega, D A; Milchev, A

2014-10-28

210

Intermediate Temperature Strength Degradation in SiC/SiC Composites  

NASA Technical Reports Server (NTRS)

Woven silicon carbide fiber-reinforced, silicon carbide matrix composites are leading candidate materials for an advanced jet engine combustor liner application. Although the use temperature in the hot region for this application is expected to exceed 1200 C, a potential life-limiting concern for this composite system exists at intermediate temperatures (800 +/- 200 C), where significant time-dependent strength degradation has been observed under stress-rupture loading. A number of factors control the degree of stress-rupture strength degradation, the major factor being the nature of the interphase separating the fiber and the matrix. BN interphases are superior to carbon interphases due to the slower oxidation kinetics of BN. A model for the intermediate temperature stress-rupture of SiC/BN/SiC composites is presented based on the observed mechanistic process that leads to strength degradation for the simple case of through-thickness matrix cracks. The approach taken has much in common with that used by Curtin and coworkers, for two different composite systems. The predictions of the model are in good agreement with the rupture data for stress-rupture of both precracked and as-produced composites. Also, three approaches that dramatically improve the intermediate temperature stress-rupture properties are described: Si-doped BN, fiber spreading, and 'outside debonding'.

Morscher, Gregory N.; Cawley, James D.; Levine, Stanley (Technical Monitor)

2001-01-01

211

Introduction to Transverse Beam Dynamics  

E-print Network

In this chapter we give an introduction to the transverse dynamics of the particles in a synchrotron or storage ring. The emphasis is more on qualitative understanding rather than on mathematical correctness, and a number of simulations are used to demonstrate the physical behaviour of the particles. Starting from the basic principles of how to design the geometry of the ring, we review the transverse motion of the particles, motivate the equation of motion, and show the solutions for typical storage ring elements. Following the usual treatment in the literature, we present a second way to describe the particle beam, using the concept of the emittance of the particle ensemble and the beta function, which reflects the overall focusing properties of the ring. The adiabatic shrinking due to Liouville's theorem is discussed as well as dispersive effects in the most simple case.

Holzer, B J

2013-01-01

212

Computational simulation of the creep-rupture process in filamentary composite materials  

NASA Technical Reports Server (NTRS)

A computational simulation of the internal damage accumulation which causes the creep-rupture phenomenon in filamentary composite materials is developed. The creep-rupture process involves complex interactions between several damage mechanisms. A statistically-based computational simulation using a time-differencing approach is employed to model these progressive interactions. The finite element method is used to calculate the internal stresses. The fibers are modeled as a series of bar elements which are connected transversely by matrix elements. Flaws are distributed randomly throughout the elements in the model. Load is applied, and the properties of the individual elements are updated at the end of each time step as a function of the stress history. The simulation is continued until failure occurs. Several cases, with different initial flaw dispersions, are run to establish a statistical distribution of the time-to-failure. The calculations are performed on a supercomputer. The simulation results compare favorably with the results of creep-rupture experiments conducted at the Lawrence Livermore National Laboratory.

Slattery, Kerry T.; Hackett, Robert M.

1991-01-01

213

Mixed adenoneuroendocrine carcinoma of the colon progressed rapidly after hepatic rupture: report of a case.  

PubMed

The rupture of a metastatic mixed adenoneuroendocrine carcinoma (MANEC) has not been previously reported, although the neuroendocrine cell carcinoma is often associated with a high incidence of hepatic metastases. The patient was a 39-year-old male who presented with upper abdominal pain over 3 months. Computed tomography showed multiple tumors in both hepatic lobes, while lower gastrointestinal endoscopy revealed a tumor in the transverse colon. Histopathologic examination of the tumor revealed it to be a neuroendocrine cell carcinoma. After the resection of the primary tumor, hepatic metastases rapidly increased, and one of them in the left lateral segment was ruptured with significant hemorrhage. The rupture led us to undertake the emergency operation to stop the bleeding. Histology showed a high-grade large-cell neuroendocrine carcinoma associated with moderately differentiated tubular adenocarcinoma. The Ki-67 labeling index was 80% (G3). The diagnosis was mixed adenoneuroendocrine carcinoma according to the 2010 World Health Organization guidelines. Hepatic arterial infusion chemotherapy, systemic chemotherapy, and transcatheter arterial chemoembolization did not decrease the tumor progress, and the patient died on postoperative day 110. Reporting this highly malignant case, I hope all doctors can be interested in MANEC. PMID:24444267

Ito, Hiromitsu; Kudo, Atsushi; Matsumura, Satoshi; Ban, Daisuke; Irie, Takumi; Ochiai, Takanori; Nakamura, Noriaki; Tanaka, Shinji; Tanabe, Minoru

2014-01-01

214

Reconstruction of a ruptured patellar tendon using ipsilateral semitendinosus and gracilis tendons with preserved distal insertions: two case reports  

PubMed Central

Background Acute patellar tendon ruptures with poor tissue quality. Ruptures that have been neglected are difficult to repair. Several surgical techniques for the repair of the patellar tendon have been reported, however, these techniques remain difficult because of contractures, adhesions, and atrophy of the quadriceps muscle after surgery. Case presentation We report the cases of 2 Japanese patients (Case 1: a 16-year-old male and Case 2: a 43-year-old male) with patellar tendon ruptures who were treated by reconstruction using semitendinosus-gracilis (STG) tendons with preserved distal insertions. Retaining the original insertion of the STG appears to preserve its viability and provide the revascularization necessary to accelerate healing. Both tendons were placed in front of the patella, in a figure-of-eight fashion, providing stability to the patella. Conclusion Both patients recovered near normal strength and stability of the patellar tendon as well as restoration of function after the operation. PMID:24010848

2013-01-01

215

Amelioration of physical strength in waste foundry green sands for reuse as a soil amendment.  

PubMed

To avoid increasing costs of landfill disposal, it has become increasingly important for U.S. foundries to identify beneficial reuses for the 8 to 12 million tons of waste foundry sand (WFS) generated annually. A major drawback to the reuse of some WFSs as a soil amendment is their high soil strength, under dry conditions, where root growth may be limited. Fifteen WFSs were analyzed for strength to rupture using lab-formed clods, exchangeable cations (Na, Mg, Ca), metal oxide concentration (Fe, Mn, Al, Si), cation exchange capacity (CEC), and % clay. Several WFS samples from gray iron foundries demonstrated high strength to rupture values (> 1.5 MPa), and could potentially restrict root growth in amended soils. The percentage of Na-bentonite exhibited a positive correlation (R(2) = 0.84) with strength to rupture values. When WFSs containing more Na-bentonite were saturated with 1 mol L(-1) Ca ions, strength values decreased by approximately 70%. Waste foundry sands containing less Na-bentonite were saturated with 1 mol L(-1) Na ions and exhibited a threefold increase in strength. Additions of gypsum (up to 9.6 g kg(-1) sand) to high strength waste foundry sands also caused decreases in strength. These results indicate that high strength WFSs have properties similar to hardsetting soils which are caused by high Na(+) clay content and can be ameliorated by the addition of Ca(2+). PMID:18948487

de Koff, J P; Lee, B D; Dungan, R S

2008-01-01

216

Creep rupture behavior of Stirling engine materials. [Iron-base NASAUT 4G-Al  

SciTech Connect

The automotive Stirling engine, being investigated jointly by the Department of Energy and NASA Lewis as an alternate to the internal combustion engine, uses high-pressure as the working fluid. The long-term effects of hydrogen on the high temperature strenth properties of materials are relatively unknown. This is especially true for the newly developed low-cost iron base alloy NASAUT 4G-Al. This iron-base alloy when tested in air has creep-rupture strengths in the directionally solidified condition comparable to the cobalt base alloy HS-31. The equiaxed (investment cast) NASAUT 4G-Al has superior creep-rupture to the equiaxed iron-base alloy XF-818 both in air and 15 MPa hydrogen.

Titran, R.H.; Scheuerman, C.M.; Stephens, J.R.

1985-01-01

217

Why Strength Training?  

MedlinePLUS

... Physical Activity Physical Activity Share Compartir Why strength training? Research has shown that strengthening exercises are both ... person's mental and emotional health. Benefits of Strength Training There are numerous benefits to strength training regularly, ...

218

Transverse stimulated Raman scattering in KDP.  

National Technical Information Service (NTIS)

Optical components of large-aperture, high irradiance and high fluence lasers can experience significant levels of stimulated scattering along their transverse dimensions. The authors have observed transverse stimulated Raman scattering in large aperture ...

C. E. Barker, R. A. Sacks, B. M. Wonterghem, J. A. Caird, J. R. Murray

1995-01-01

219

Detection of supershear rupture in 2013 Craig, Alaska, earthquake  

NASA Astrophysics Data System (ADS)

Seismic ruptures are akin to opening a zipper梐 gap in the crust starts in one location and travels along the fault in a particular direction. When a strained fault ruptures in an earthquake, seismic waves also spread out from the epicenter. In some cases, the waves' passage can trigger the initiation of a new rupture ahead of the initial expanding rupture in locked portions of the fault. If the triggered rupture grows successfully, the overall rupture front can then outpace the passage of the shear waves, secondary seismic waves that travel slowly after the earthquake begins and are responsible for the bulk of violent shaking. These earthquakes display what is known as supershear rupture; only seven such earthquakes have previously been recorded.

Schultz, Colin

2014-01-01

220

Trichomonas vaginalis Weakens Human Amniochorion in an In Vitro Model of Premature Membrane Rupture  

PubMed Central

Objective: Trichomonas vaginalis (TV) infection is associated with preterm rupture of membranes (PROM) and preterm birth. We evaluated the effects of TV growth and metabolism on preparations of human amniochorion to understand and characterize how TV may impair fetal-membrane integrity and predispose to PROM and preterm birth. Methods: Term fetal membranes were evaluated using an established in vitro fetal-membrane model. Fresh TV clinical isolates were obtained from pregnant women. The protozoa (5.0105 to 1.5106/ml) were incubated with fetal membranes in modified Diamond's medium for 20 h at 37癈 in 5% CO2.The effects of fetal-membrane strength (bursting tension, work to rupture, and elasticity) were measured using a calibrated Wheatstone-bridge dynamometer. Tests were also performed to evaluate the effects of 1) inoculum size; 2) metronidazole (50 ?g/ml); and 3) cell-free filtrate. Results: The TV-induced membrane effects were 1) isolate variable; 2) inoculum dependent; 3) incompletely protected by metronidazole; and 4) mediated by both live organisms as well as protozoan-free culture filtrates. Six of 9 isolates significantly reduced the calculated work to rupture (P ? 0.02); 7 of 9 reduced bursting tension; and 1 of 9 reduced elasticity. One isolate significantly increased the work to rupture and bursting tension (P ? 0.002). Conclusions: In vitro incubation of fetal membranes with TV can significantly impair the measures of fetal-membrane strength. This model may be used to delineate the mechanisms of TV-induced membrane damage. This study suggests that there are enzyme-specific effects as well as pH effects. PMID:18475407

Jones, Ward; Heine, R. Phillip; Beutz, Michelle; French, Janice I.; McGregor, James A.

1995-01-01

221

Determination of Early Age Mortar and Concrete Strength by Ultrasonic Wave Reflections  

E-print Network

Determination of Early Age Mortar and Concrete Strength by Ultrasonic Wave Reflections Thomas Voigt of early age concrete strength is crucial for determining the time of form removal from concrete elements strength, concrete, mortars, hydration, wave reflection, transverse waves ABSTRACT The in-situ testing

222

Creep-rupture behavior of forged, thick section 9Cr-1Mo ferritic steel  

SciTech Connect

Detailed investigations have been performed to examine the creep-rupture behavior of a 1,000-mm diameter and 300-mm-thick tube plate forging of 9Cr-1Mo ferritic steel in quenched and tempered (Q + T), simulated postweld heat treatment (SPWHT), and thermally aged (TA) conditions. Creep tests were conducted over a wide stress range (50 to 275 MPa) at 793 and 873 K. The alloy exhibited well-defined primary, steady-state, and extended tertiary creep stages at all test conditions. At 793 K, no significant difference in the creep-rupture properties was noted between Q + T, SPWHT, and TA conditions. On the other hand, SPWHT specimens exhibited lower creep-rupture strength than that of Q + T specimens at 873 K. Applied stress ({sigma}{sub a}) dependence of rupture life (t{sub r}) exhibited two-slope behavior. Both the Monkman-Grant ({dot {epsilon}}{sub s}.t{sub r} = C{sub MG}) and modified Monkman-Grant ({dot {epsilon}}.t{sub r}/{epsilon}{sub f} = C{sub MMG}) relationships were found to be valid for 9Cr-1Mo steel, where {dot {epsilon}}{sub s} is the steady-state creep rate and {epsilon}{sub f} is the strain to failure. The two-slope behavior was also reflected as two constants in the Monkman-Grant relationship (MGR) and modified Monkman-Grant relationship (MMGR) in the two stress regimes. Further, two creep damage tolerance factors ({lambda} = 1/C{sub MMG}) of 5 and 10 were also observed in the high and low stress regimes, respectively. The alloy exhibited high creep ductility, which was retained for longer rupture lives at low stresses, and the creep ductility increased with increase in test temperature. The failure mode remained transgranular under all test conditions. The extensive tertiary creep in the alloy has been attributed to microstructural degradation associated with precipitates and dislocation substructure. The creep-rupture strength of the forging was found to be lower than that of thin section bars and tubes.

Choudhary, B.K.; Saroja, S.; Rao, K.B.S.; Mannan, S.L.

1999-11-01

223

Retinal detachment associated with traumatic chorioretinal rupture.  

PubMed

Traumatic chorioretinal rupture, also known as sclopetaria, is a full-thickness break of the choroid and retina caused by a high-velocity projectile striking or passing adjacent to, but not penetrating, the globe. Previous reports have emphasized that retinal detachment seldom occurs, and observation alone has been the recommended management strategy. However, the authors present herein a series of consecutive patients with retinal detachment associated with sclopetaria and provide a literature review of the topic. They recommend that patients with traumatic chorioretinal rupture be monitored closely for the development of retinal detachment during the first few weeks after the injury. [Ophthalmic Surg Lasers Imaging Retina. 2014;45:451-455.]. PMID:25153657

Papakostas, Thanos D; Yonekawa, Yoshihiro; Wu, David; Miller, John B; Veldman, Peter B; Chee, Yewlin E; Husain, Deeba; Eliott, Dean

2014-09-01

224

Treatment of Ruptured ICA during Transsphenoidal Surgery  

PubMed Central

Summary Rupture of the internal carotid artery (ICA) during transsphenoidal surgery is a rare but potentially lethal complication. Direct surgical repair of the ICA may be difficult and time-consuming in an acute setting. Urgent endovascular treatments with vascular plug or stent-graft have been the feasible options to date. We desrcibe two cases of iatrogenic rupture of ICA during transsphenoidal surgery. In the first case we occluded the ICA with a vascular plug at the site of tear where cross circulation was adequate. In the second case we had to preserve the ICA with stent-graft since there was no adequate cross circulation. These two strategies are discussed below. PMID:20377977

Ghatge, S.B.; Modi, D.B.

2010-01-01

225

An unusual diagnosis of splenic rupture.  

PubMed

A 22-year-old woman presented with a 3-day history of worsening epigastric pain, non-productive cough and vomiting. On examination she was pale and had abdominal tenderness predominant in the right upper quadrant. Abdominal ultrasound excluded the presence of gall stones, but was unable to rule out free fluid in the abdomen. CT demonstrated extensive high-density ascites; however, no source of bleeding could be demonstrated. Clinically the patient's condition deteriorated, and an exploratory laparotomy was performed. In theatre the splenic capsule was found to have detached from the splenic body and emergency splenectomy was performed. Virology serology later demonstrated acute cytomegalovirus (CMV) infection, although tissue microscopy and CMV staining were negative. No other cause of rupture was found. The interesting aspects of this case include the poor correlation between initial presenting symptoms and subsequent diagnosis, the difficulty encountered in making a firm diagnosis and the atypical cause of rupture. PMID:25293683

Roche, Matthew; Maloku, Fatmir; Abdel-Aziz, Tarek Ezzat

2014-01-01

226

Premature rupture of the membranes: neonatal consequences.  

PubMed

Premature rupture of the membranes (PROM), membrane rupture before the onset of labor, occurs in 2% to 18% of pregnancies. The time from PROM to delivery (latency) is usually less than 48 hours in term pregnancy. Therefore, the risks of PROM at term are related to fetal distress, prolapsed cord, abruptio placenta, and rarely, infection. Preterm PROM (pPROM), PROM before 37 weeks' gestation, accounts for 20% to 40% of PROM, and the incidence is doubled in multiple gestations. The latency period in pPROM is inversely related to the gestational age thereby increasing the risks of oligohydramnios and infection in very premature infants and their mothers. Because pPROM is associated with 30% to 40% of premature births, pPROM is also responsible for the neonatal problems resulting from prematurity. This review examines the impact of PROM on the neonate including fetal distress, prematurity, infection, pulmonary hypoplasia, and restriction deformations. PMID:8912991

Merenstein, G B; Weisman, L E

1996-10-01

227

Traumatic dislocation of testes and bladder rupture.  

PubMed

Traumatic dislocation of the testes with bladder rupture occurred in 2 multiply injured patients with pelvic fracture. One had a history of retractile testes and the other of previous testicular dislocation. Surgical correction was performed after closed reduction failed. These injuries must be recognized and treated promptly to maximize the likelihood of testicular salvage. If early intervention is not possible, duplex ultrasonography and pulsed Doppler analysis are the optional valuative studies. PMID:1466102

Lee, J Y; Cass, A S; Streitz, J M

1992-12-01

228

Solving the dynamic rupture problem with different numerical approaches and constitutive laws  

USGS Publications Warehouse

We study the dynamic initiation, propagation and arrest of a 2-D in-plane shear rupture by solving the elastodynamic equation by using both a boundary integral equation method and a finite difference approach. For both methods we adopt different constitutive laws: a slip-weakening (SW) law, with constant weakening rate, and rate- and state-dependent friction laws (Dieterich-Ruina). Our numerical procedures allow the use of heterogeneous distributions of constitutive parameters along the fault for both formulations. We first compare the two solution methods with an SW law, emphasizing the required stability conditions to achieve a good resolution of the cohesive zone and to avoid artificial complexity in the solutions. Our modelling results show that the two methods provide very similar time histories of dynamic source parameters. We point out that, if a careful control of resolution and stability is performed, the two methods yield identical solutions. We have also compared the rupture evolution resulting from an SW and a rate- and state-dependent friction law. This comparison shows that despite the different constitutive formulations, a similar behaviour is simulated during the rupture propagation and arrest. We also observe a crack tip bifurcation and a jump in rupture velocity (approaching the P-wave speed) with the Dieterich-Ruina (DR) law. The rupture arrest at a barrier (high strength zone) and the barrier-healing mechanism are also reproduced by this law. However, this constitutive formulation allows the simulation of a more general and complex variety of rupture behaviours. By assuming different heterogeneous distributions of the initial constitutive parameters, we are able to model a barrier-healing as well as a self-healing process. This result suggests that if the heterogeneity of the constitutive parameters is taken into account, the different healing mechanisms can be simulated. We also study the nucleation phase duration Tn, defined as the time necessary for the crack to reach the half-length Ic. We compare the Tn values resulting from distinct simulations calculated using different constitutive laws and different sets of constitutive parameters. Our results confirm that the DR law provides a different description of the nucleation process than the SW law adopted in this study. We emphasize that the DR law yields a complete description of the rupture process, which includes the most prominent features of SW.

Bizzarri, A.; Cocco, M.; Andrews, D. J.; Boschi, E.

2001-01-01

229

[Splenic artery rupture in pancreatic pseudocyst].  

PubMed

Hemorrhage is one of the most threatening complication of pancreatic pseudocyst. It results from erosion of adjacent vessels. Splenic, gastroduodenal, pancreaticoduodenal and middle colic vessels are predominantly involved. Hemorrhage may present different feature: intra and/or extraperitoneal collection, gastrointestinal bleeding. The authors report the rupture of splenic artery into pseudocyst, with the formation of pulsating pseudoaneurysm, increasing progressively until the final rupture. For the diagnosis the authors utilized: ultrasounds (US) which showed the cyst but not its nature and content; the CT scan which disclosed haematic contents; finally the US Color Doppler which proved the dynamic feature of hemorrhage. This technique allows to identify the arterious or venous source of bleeding and the possible presence of arteriovenous fistula. Arteriography was not performed due to circumstances, although it would permit bleeding vessel embolization and the control of hemorrhage. This procedure is not ever achievable, and doesn't exclude the possibility of rebleeding. On surgery, since the intraoperative rupture of the pseudoaneurysm occurred with severe hypovolemic shock, only a timely posterior mesogastric mobilization and the medially displacement of spleen-body-tail pancreatic complex, allowed to clamp the mass and the hemostasis. When such lesion are approached, it is mandatory to be prepared to carry on this maneuver: the severity of bleeding cannot allow intracystic ligature of bleeding vessel. PMID:10920499

Ungania, S; Panocchia, N

2000-01-01

230

[Diagnosis and treatment of diaphragm traumatic ruptures].  

PubMed

29 patients with traumatic ruptures of left cupola of the diaphragm were studied. Pain, dispnoe, tachycardia more intensive after a meal due to repletion and dislocation of the stomach into pleural cavity and its pressure on the organs of the mediastinum were the main symptoms of the disease. The diagnosis of traumatic rupture of the diaphragm was made on the base of clinical and roentgenological examination. In the acute period of trauma the diagnosis is difficult, especially in combined trauma. In 92.3% of cases the stomach and the bowel move into the pleural cavity, which may simulate pneumothorax or relaxation of the diaphragm. Contrast examination of the gastro-intestinal tract and pleural puncture help in differential diagnosis. All the cases of traumatic ruptures of the diaphragm should be subjected to surgical treatment. Urgent operation is indicated in continuing bleeding, incarceration of organs, acute cardiopulmonary insufficiency due to the collapse of the lung and dislocation of mediastinal organs of into contralateral position. Thoracotomy in VII intercostal space is considered as a valid approach. There were 2 (6.9%) lethal outcomes after 29 operations. Long-term results are quite favourable. PMID:10459187

Gadzhiev, Sh M; Gurbanaliev, I G; Abbasov, F; Mamedov, A S; Ze?nalov, N D; Iusifov, I A

1999-01-01

231

Ruptured Corpus Luteal Cyst: CT Findings  

PubMed Central

Objective To evaluate the CT findings of ruptured corpus luteal cysts. Materials and Methods Six patients with a surgically proven ruptured corpus luteal cyst were included in this series. The prospective CT findings were retrospectively analyzed in terms of the size and shape of the cyst, the thickness and enhancement pattern of its wall, the attenuation of its contents, and peritoneal fluid. Results The mean diameter of the cysts was 2.8 (range, 1.5-4.8) cm; three were round and three were oval. The mean thickness of the cyst wall was 4.7 (range, 1-10) mm; in all six cases it showed strong enhancement, and in three was discontinuous. In five of six cases, the cystic contents showed high attenuation. Peritoneal fluid was present in all cases, and its attenuation was higher, especially around the uterus and adnexa, than that of urine present in the bladder. Conclusion In a woman in whom CT reveals the presence of an ovarian cyst with an enhancing rim and highly attenuated contents, as well as highly attenuated peritoneal fluid, a ruptured corpus luteal cyst should be suspected. Other possible evidence of this is focal interruption of the cyst wall and the presence of peritoneal fluid around the adnexa. PMID:12679633

Choi, Hyuck Jae; Kim, Sun Ho; Kim, Hyo-Cheol; Park, Chang Min; Lee, Hak Jong; Moon, Min Hoan; Jeong, Jun Yong

2003-01-01

232

Single Event Gate Rupture in EMCCD technology  

NASA Astrophysics Data System (ADS)

The high electric fields (typically 3 MV/cm2 interpoly field) utilised in Electron Multiplying Charged Coupled Devices (EMCCDs) reveal a potential vulnerability from Single Event Phenomena (SEP), in particular Single Event Gate Rupture (SEGR). SEGR is where a conduction path between two conductive areas of the CCD is produced, causing device failure. If EMCCDs are to be used for space applications the susceptibility to these events needs to be explored. A positive result from such an investigation can increase the technology readiness level of the device moving it another step closer to being used in space. Testing undertaken at the CYClotron of LOuvain la NEuve (CYCLONE), using the Heavy Ion Facility (HIF), conclusively showed EMCCD technology to have resilience to heavy ions that surpassed initial expectations. The simulations undertaken prior to experiment suggested gate rupture would occur at 20-40 MeV cm2/mg, however Linear Energy Transfers (LETs) greater than 100 MeV cm2/mg proved to not cause a rupture event. Within the radiation belts heavy ions with an LET greater than 60 MeV cm2/mg are not very common when compared to the fluxes used at the HIF. Possible reasons for this result are discussed in this work, leading to a conclusion that EMCCD technology is a secure choice for space flight.

Evagora, A. M.; Murray, N. J.; Holland, A. D.; Burt, D.

2012-12-01

233

Biosensing using rupture event scanning (REVS)  

NASA Astrophysics Data System (ADS)

We have developed a sensitive and economical method to detect analytes directly. The technique, which we term rupture event scanning (REVS), is based on rapidly oscillating an acoustic wave device on which the analytes have been captured. As the magnitude of oscillation of the surface of the acoustic wave device is increased, there is increasing acceleration of adherent analytes. This in turn results in a larger force exerted by the surface on the particle, that ultimately causes rupture of the bonds attaching the particle to the surface. Using the same device, we can very sensitively monitor the excitation of vibrations in the acoustic wave device produced by bond rupture, which are then converted into an electrical signal. The signal indicates not only the presence of specifically bound analytes and their affinity for the receptor, but also the number of analytes present. The method works in air, water and complex biological fluids, is quantitative over at least six orders of magnitude of particle titre, and in affinity from sub-mM to pM. For selected analyte-receptor systems the sensitivity can be as low as 80 fg mm-2 (8 10-14 g mm-2). In this paper an example application of REVS is presented and the physical forces involved in the process are discussed.

Cooper, Matthew A.

2003-11-01

234

Operative intra-aortic balloon rupture.  

PubMed

Rupture of an intra-aortic balloon (IAB), inserted to assist in weaning from cardiopulmonary bypass, occurred during attempted intra-aortic administration of protamine in a 71-year-old male who later died. Intra-aortic balloon counterpulsation (IABC) is most commonly utilized to assist in weaning from cardiopulmonary bypass (CPB) or to augment low-flow states following CPB. In-hospital survival following IAB insertion in these circumstances in patients with coronary artery disease is approximately 60 per cent. Patients with valvular disease have a lower in-hospital survival rate (50 per cent). Complications of IABC are usually of vascular or infectious origin. Balloon rupture is a rare though potentially lethal complication. The effects of balloon rupture may be compounded by the use of helium as a driving gas to inflate the balloon. Intra-aortic administration of protamine has not been shown to be superior to peripheral administration and should be avoided if an IAB is in place. PMID:3383321

Finegan, B A; Comm, D G

1988-05-01

235

A Transversely Isotropic Thermoelastic Theory  

NASA Technical Reports Server (NTRS)

A continuum theory is presented for representing the thermoelastic behavior of composites that can be idealized as transversely isotropic. This theory is consistent with anisotropic viscoplastic theories being developed presently at NASA Lewis Research Center. A multiaxial statement of the theory is presented, as well as plane stress and plane strain reductions. Experimental determination of the required material parameters and their theoretical constraints are discussed. Simple homogeneously stressed elements are examined to illustrate the effect of fiber orientation on the resulting strain distribution. Finally, the multiaxial stress-strain relations are expressed in matrix form to simplify and accelerate implementation of the theory into structural analysis codes.

Arnold, S. M.

1989-01-01

236

Liver Hydatid Cyst with Transdiaphragmatic Rupture and Lung Hydatid Cyst Ruptured into Bronchi and Pleural Space  

SciTech Connect

The aim of this case study is to present effectiveness of percutaneous drainage as a treatment option of ruptured lung and liver hydatid cysts. A 65-year-old male patient was admitted with complicated liver and lung hydatid cysts. A liver hydatid cyst had ruptured transdiaphragmatically, and a lung hydatid cyst had ruptured both into bronchi and pleural space. The patient could not undergo surgery because of decreased respiratory function. Both cysts were drained percutaneously using oral albendazole. Povidone-iodine was used to treat the liver cyst after closure of the diaphragmatic rupture. The drainage was considered successful, and the patient had no recurrence of signs and symptoms. Clinical, laboratory, and radiologic recovery was observed during 2.5 months of catheterization. The patient was asymptomatic after catheter drainage. No recurrence was detected during 86 months of follow-up. For inoperable patients with ruptured liver and lung hydatid cysts, percutaneous drainage with oral albendazole is an alternative treatment option to surgery. The percutaneous approach can be life-saving in such cases.

Ar Latin-Small-Letter-Dotless-I bas, Bilgin Kadri, E-mail: bilginaribas@hotmail.com; Dingil, Guerbuez [A.Y. Ankara Oncology Training and Research Hospital, Department of Radiology (Turkey); Koeroglu, Mert [Sueleyman Demirel University School of Medicine, Department of Radiology (Turkey); Uenguel, Uemit; Zaral Latin-Small-Letter-Dotless-I , Aliye Ceylan [A.Y. Ankara Oncology Training and Research Hospital, Department of Radiology (Turkey)

2011-02-15

237

Transverse Momentum Distributions for Heavy Quark Pairs  

E-print Network

We study the transverse momentum distribution for a $pair$ of heavy quarks produced in hadron-hadron interactions. Predictions for the large transverse momentum region are based on exact order $\\alpha_s^3$ QCD perturbation theory. For the small transverse momentum region, we use techniques for all orders resummation of leading logarithmic contributions associated with initial state soft gluon radiation. The combination provides the transverse momentum distribution of heavy quark pairs for all transverse momenta. Explicit results are presented for $b\\bar b$ pair production at the Fermilab Tevatron collider and for $c\\bar c$ pair production at fixed target energies.

Edmond L. Berger; Ruibin Meng

1993-10-22

238

Tensile properties of short fiber composites with fiber strength distribution  

Microsoft Academic Search

The influence of fiber rupture, fiber pull-out and fiber tensile strength distribution on the post-cracking behavior of short-randomly-distributed fiber reinforced brittle-matrix composites has been analyzed using an approach based on the Weibull weakest-link statistics. The analysis led to the development of a predicting model for the composite bridging stress-crack opening displacement (sc - d) law梐 fundamental material property necessary for

M. Maalej

2001-01-01

239

Estrogen protects against intracranial aneurysm rupture in ovariectomized mice.  

PubMed

Clinical observations suggest that postmenopausal women have a higher incidence of aneurysmal rupture than premenopausal women. We hypothesize that a relative deficiency in estrogen may increase the risks of aneurysmal growth and subarachnoid hemorrhage in postmenopausal women. We assessed the effects of estrogen and selective estrogen receptor subtype agonists on the development of aneurysmal rupture in ovariectomized female mice. We used an intracranial aneurysm mouse model that recapitulates the key features of human intracranial aneurysms, including spontaneous rupture. Ten- to 12-week-old ovariectomized female mice received treatment with estrogen, nonselective estrogen receptor antagonist, estrogen receptor-? agonist, or estrogen receptor-? agonist starting 6 days after aneurysm induction so that the treatments affected the development of aneurysmal rupture without affecting aneurysmal formation. Estrogen significantly reduced the incidence of ruptured aneurysms and rupture rates in ovariectomized mice. Nonselective estrogen receptor antagonist abolished the protective effect of estrogen. Although estrogen receptor-? agonist did not affect the incidence of ruptured aneurysms or rupture rates, estrogen receptor-? agonist prevented aneurysmal rupture without affecting the formation of aneurysms. The protective role of estrogen receptor-? agonist was abolished by the inhibition of nitric oxide synthase. We showed that estrogen prevented aneurysmal rupture in ovariectomized female mice. The protective effect of estrogen seemed to occur through the activation of estrogen receptor-?, a predominant subtype of estrogen receptor in human intracranial aneurysms and cerebral arteries. PMID:24732889

Tada, Yoshiteru; Wada, Kosuke; Shimada, Kenji; Makino, Hiroshi; Liang, Elena I; Murakami, Shoko; Kudo, Mari; Shikata, Fumiaki; Pena Silva, Ricardo A; Kitazato, Keiko T; Hasan, David M; Kanematsu, Yasuhisa; Nagahiro, Shinji; Hashimoto, Tomoki

2014-06-01

240

[Evaluation of surgical repair of distal biceps tendon ruptures].  

PubMed

PURPOSE OF THE STUDY To present the results of surgical repair of ruptures of the distal tendon of the biceps brachii muscle and thus show the adequacy of this treatment. MATERIAL Between 1987 and 2006, 19 patients had surgery for distal biceps tendon rupture. Only one side was affected in each patient. All patients were men between 28 and 69 years (average age, 47.5 years) at the time of injury (surgery). When the patients were evaluated at the end of 2007, 18 patients were included, because one died a year after surgery. METHODS The surgical repair always included a single-incision anatomical reattachment into the radial tuberosity. In 11 patients, a modified Mac Reynolds method with screw and washer fixation was used; in seven patients the insertion was fixed with Mitek anchors and, in one, it was sutured to the adjacent soft tissues. The average follow-up was 7 years (range, 1 to 20.5 years). The patients were evaluated for the cause of injury, their physical activity, age, dominance of the injured arm, surgical procedure and complications. RESULTS In 18 patients surgical repair was done early and, in one, at 16 days after injury. In all of them the tendon was detached from its site of insertion, but never torn. The intra-operative complications included, in one patient, bleeding owing to iatrogenic damage to a branch of the brachial artery, and difficult separation of the tendon due to its previous healed injury in another patient. Early post-operative complications included superficial skin necrosis in one patient and transient neurological deficit of the dorsal brand of the radial nerve and of the lateral cutaneous nerve of the forearm in two and one patient, respectively. The late complications were heterotropic ossification in three patients and screw migration in the one treated by the Mac Reynolds method. Excellent results were recorded in 11 patients (61 %), and good outcomes with a slight restriction of motion or muscle strength not limiting the patient's physical activities were in six (33.5 %) patients; only one patient (5.5 %) experienced pain on moderate exercise and had recurrent heterotropic ossification. Apart from this condition, there was no difference in the frequency of complications associated with the method used. DISCUSSION Only sparse information on distal biceps tendon ruptures has been available in the relevant Czech literature and, if so, only small groups with short follow-ups have been involved. Conservative treatment or the methods of non-anatomical reattachment have poor functional outcomes. Much better results are achieved by anatomical reattachment. Based on our experience with the Mac Reynolds technique, an anterior single-incision approach using fixation with Mitek anchors can be recommended. CONCLUSIONS Early surgical repair involving anatomical reattachment from the anterior singleincision approach with two Mitek anchors is recommended when a rupture of the distal tendon insertion of the biceps brachii is diagnosed. Key words: biceps radii muscle, biceps tendon injury, tendon fixation, bone screw and washer use. PMID:19268049

Behounek, J; Hrubina, M; Skot醟, M; Krumpl, O; Zah醠ka, M; Dvor醟, J; Fuc韐, M

2009-02-01

241

Intermediate Temperature Stress Rupture of Woven SiC Fiber, BN Interphase, SiC Matrix Composites in Air  

NASA Technical Reports Server (NTRS)

Tensile stress-rupture experiments were performed on woven Hi-Nicalon reinforced SiC matrix composites with BN interphases in air. Modal acoustic emission (AE) was used to monitor the damage accumulation in the composites during the tests and microstructural analysis was performed to determine the amount of matrix cracking that occurred for each sample. Fiber fractograph), was also performed for individual fiber failures at the specimen fracture surface to determine the strengths at which fibers failed. The rupture strengths were significantly worse than what would have been expected front the inherent degradation of the fibers themselves when subjected to similar rupture conditions. At higher applied stresses the rate of rupture "?as larger than at lower applied stresses. It was observed that the change in rupture rate corresponded to the onset of through-thickness cracking in the composites themselves. The primary cause of the sen,ere degradation was the ease with which fibers would bond to one another at their closest separation distances, less than 100 nanometers, when exposed to the environment. The near fiber-to-fiber contact in the woven tows enabled premature fiber failure over large areas of matrix cracks due to the stress-concentrations created b), fibers bonded to one another after one or a few fibers fail. i.e. the loss of global load sharing. An@, improvement in fiber-to-fiber separation of this composite system should result in improved stress- rupture properties. A model was den,eloped in order to predict the rupture life-time for these composites based on the probabilistic nature of indin,idual fiber failure at temperature. the matrix cracking state during the rupture test, and the rate of oxidation into a matrix crack. Also incorporated into the model were estimates of the stress-concentration that would occur between the outer rim of fibers in a load-bearing bundle and the unbridged region of a matrix crack after Xia et al. For the lower stresses, this source of stress-concentration was the likely cause for initial fiber failure that would trigger catastrophic failure of the composite.

Morscher, Gregory N.; Levine, Stanley (Technical Monitor)

2000-01-01

242

Synergy and interactions among biological pathways leading to preterm premature rupture of membranes.  

PubMed

Preterm premature rupture of membranes (PPROM) occurs in 1% to 2% of births. Impact of PPROM is greatest in low- and middle-income countries where prematurity-related deaths are most common. Recent investigations identify cytokine and matrix metalloproteinase activation, oxidative stress, and apoptosis as primary pathways to PPROM. These biological processes are initiated by heterogeneous etiologies including infection/inflammation, placental bleeding, uterine overdistention, and genetic polymorphisms. We hypothesize that pathways to PPROM overlap and act synergistically to weaken membranes. We focus our discussion on membrane composition and strength, pathways linking risk factors to membrane weakening, and future research directions to reduce the global burden of PPROM. PMID:24840939

Lannon, Sophia M R; Vanderhoeven, Jeroen P; Eschenbach, David A; Gravett, Michael G; Adams Waldorf, Kristina M

2014-10-01

243

Dynamics of three-dimensional thin film rupture  

NASA Astrophysics Data System (ADS)

We consider the problem of thin film rupture driven by van der Waals forces. A fourth-order nonlinear PDE governs the low Reynolds number lubrication model for a viscous liquid on a solid substrate. Finite-time singularities in this equation model rupture leading to formation of dry spots in the film. Our study addresses the problem of rupture in the full three-dimensional geometry. We focus on stability and selection of the dynamics determined by the initial conditions on small finite domains with planar and axisymmetric geometries. We also address the final stages of the dynamics - self-similar dynamics for point, line, and ring rupture. We will demonstrate that line and ring rupture are unstable and will generically destabilize to produce axisymmetric rupture at isolated points.

Witelski, Thomas P.; Bernoff, Andrew J.

2000-12-01

244

Transverse-longitudinal integrated resonator  

DOEpatents

A transverse-longitudinal integrated optical resonator (TLIR) is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide. The PBG is positioned between the first and second subwavelength resonant gratings. An electro-optic waveguide material may be used to permit tuning the TLIR and to permit the TLIR to perform signal modulation and switching. The TLIR may be positioned on a bulk substrate die with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a TLIR including fabricating a broadband reflective grating is disclosed. A method for tuning the TLIR's transmission resonance wavelength is also disclosed.

Hutchinson, Donald P [Knoxville, TN; Simpson, Marcus L [Knoxville, TN; Simpson, John T [Knoxville, TN

2003-03-11

245

Transverse Patterning and Human Amnesia  

PubMed Central

The transverse patterning (TP) task (A+ B?, B+ C?, C+ A?) has played a central role in testing the hypothesis that medial-temporal (and, in particular, hippocampal) brain damage selectively impairs learning on at least some classes of configural (i.e., nonlinear) learning tasks. Results in the animal and human literature generally support that hypothesis. Reed and Squire [Impaired transverse patterning in human amnesia is a special case of impaired memory for two-choice discrimination tasks. Behavioral Neuroscience, 113, 39, 1999], however, advanced an alternative account in which impaired TP performance in amnesia reflects a generic scaling artifact arising from the greater difficulty of the TP task compared to the elemental (i.e., linear) control task that is typically used. We begin with a critique of Reed and Squire, countering their conceptual arguments and showing that their results, when analyzed appropriately, support the configural deficit hypothesis. We then report results from eight new amnesic patients and controls on an improved version of the TP task. Despite substantial practice, accuracy of patients with bilateral hippocampal damage due to anoxia reached and maintained an asymptote of only 54% correct, well below the maximum accuracy obtainable (67%) in the absence of configural learning. A patient with selective bilateral damage to the anterior thalamic nuclei exhibited a TP accuracy asymptote that was near 67%, a pattern of two out of three correct consecutive trials, and a pattern of nearly always answering correctly for two of the three TP item pairs. These results are consistent with a set of unique and parameter-free predictions of the configural deficit hypothesis. PMID:17014376

Verfaellie, Mieke; Grafman, Jordan

2006-01-01

246

Uterine rupture following termination of pregnancy in a scarred uterus.  

PubMed

We present a series of two cases complicated by uterine rupture following termination of pregnancy (TOP) in the 1st and 2nd trimesters using misoprostol in women with caesarean section scar. Current literature and practise have also been reviewed on ruptured uterus in women with caesarean section scar undergoing TOP using misoprostol; the diagnosis of adherent placenta in the 1st and 2nd trimesters in women with previous caesarean uterine scar; and likely implications of a ruptured uterus. PMID:24456452

Bika, O; Huned, D; Jha, S; Selby, K

2014-02-01

247

[Bilateral uterine rupture of an unscarred gravid uterus before labor].  

PubMed

We report a case of bilateral spontaneous uterine rupture of an unscarred uterus occured in a primigravida at 32 weeks to take care in our department after in utero transfert. Uterine rupture occurs mainly on scarred uterus during labor. This is an unfrequent but serious complication involving fetal-maternal prognosis in the absence of immediate care. We are conducting a review about spontaneous uterine rupture of unscarred uterus, before and during labor. PMID:24394323

Leroux, M; Coatleven, F; Faure, M; Horovitz, J

2014-06-01

248

Successful infarct exclusion for postinfarction left ventricular free wall rupture  

PubMed Central

The mortality of postinfarction left ventricular free wall rupture is still high. Several surgical techniques have been used for repairing such ruptures. Here, we describe using an infarction exclusion technique to successfully treat a case of a blow-out type postinfarction left ventricular free wall rupture. This technique has frequently been used for repairing postinfarction ventricular septal perforation. In this case, infarcted myocardial tearing was prevented, and complete haemostasis was achieved by infarct exclusion. PMID:23424241

Kato, Yasuyuki; Fukui, Toshihiro; Tabata, Minoru; Takanashi, Shuichiro

2013-01-01

249

Migraine before rupture of intracranial aneurysms  

PubMed Central

Background Rupture of a saccular intracranial aneurysm (SIA) causes thunderclap headache but it remains unclear whether headache in general and migraine in particular are more prevalent in patients with unruptured SIA. Methods In a prospective case朿ontrol study 199 consecutive patients with SIA (103 females and 96 males, mean age: 43.2爕ears) received a semistructured face to face interview focusing on past headaches. All were admitted to hospital mostly because of rupture (177) or for unruptured aneurysm (22). In parallel we interviewed 194 blood donors (86 females, 108 males, mean age: 38.4爕ears). Diagnoses were made according to the International Headache Society criteria. Aneurysms were diagnosed by conventional cerebral angiography. Results During the year before rupture, 124 (62.3%) had one or more types of headache. These headaches included: migraine without aura (MO): 78 (39.2%), migraine with aura (MA): 2 (1%), probable migraine (PM): 4 (2%), tension-type headache (TTH): 39 (19.6%), cluster headache (CH): 2 (1%), posttraumatic headaches (PH): 2 (1%). 1-year prevalence of headaches in controls was 32.5% (63 patients out of 194), they included: TTH: 45 (23.1%), MO: 17(8.8%), PH: 1(0.5%). Only the prevalence of MO was significantly higher in patients with SIA (OR 6.7, 95% CI 3.8-11.9, p?

2013-01-01

250

Forecasting the Rupture Directivity of Large Earthquakes  

NASA Astrophysics Data System (ADS)

Forecasting the rupture directivity of large earthquakes is an important problem in probabilistic seismic hazard analysis (PSHA), because directivity strongly influences ground motions. We cast this forecasting problem in terms of the conditional hypocenter distribution (CHD), defined to be the probability distribution of a hypocenter given the spatial distribution of fault slip (moment release). The simplest CHD is a uniform distribution for which the hypocenter probability density equals the moment-release probability density. We have compiled samples of CHDs from a global distribution of large earthquakes using three estimation methods: (a) location of hypocenters within the slip distribution from finite-fault inversions, (b) location of hypocenters within early aftershock distributions, and (c) direct inversion for the directivity parameter D, defined in terms of the degree-two polynomial moments of the source space-time function. The data from method (a) are statistically inconsistent with the uniform CHD suggested by McGuire et al. (2002) using method (c). Instead, the data indicate a 'centroid-biased' CHD, in which the expected distance between the hypocenter and the hypocentroid is less than that of a uniform CHD; i.e., the directivities inferred from finite-fault models appear to be closer to bilateral than predicted by the uniform CHD. One source of this discrepancy may be centroid bias in the second-order moments owing to poor localization of the slip in finite-fault inversions. We compare these observational results with CHDs computed from a large set of theoretical ruptures in the Southern California fault system produced by the Rate-State Quake simulator (RSQSim) of Dieterich and Richards-Dinger (2010) and discuss the implications for rupture dynamics and fault-zone heterogeneities.

Donovan, J. R.; Jordan, T. H.

2013-12-01

251

Capturing Continental Rupture Processes in Afar  

NASA Astrophysics Data System (ADS)

Both continental and oceanic rifting processes are highly 3D, but the stability of the along-axis segmentation from rifting to breakup, and its relationship to seafloor spreading remains debated. Three-dimensional models of the interactions of faults and magmatism in time and space are in development, but modelling and observations suggest that magmatic segments may propagate and/or migrate during periods of magmatism. Our ability to discriminate between the various models in large part depends on the quality of data in the ocean-transition zone, or, observations from zones of incipient plate rupture. Largely 2D crustal-scale seismic data from magmatic passive margins reveal large magmatic additions to the crust, but the timing of this heat and mass transfer is weakly constrained. Thus, the lack of information on the across rift breadth of the deforming zone at rupture, and the relationship between the early rift segmentation and the seafloor spreading segmentation represent fundamental gaps in knowledge. Our study of Earth's youngest magmatic margin, the superbly exposed, tectonically active southern Red Sea, aims to answer the following questions: What are the geometry and kinematics of active fault systems across the 'passive margin' to zone of incipient plate rupture? What is the relationship between the initial border fault segmentation, and the breakup zone segmentation? What is the distribution of active deformation and magmatism, and how does it compare to time-averaged strain patterns? We integrate results of recent experiments that suggest widespread replacement of crust and mantle lithosphere beneath the 'passive' margin, and explain the ongoing seismic deformation as a consequence of bending stresses across the ocean-continent transition, with or without a dynamic component.

Ebinger, Cynthia; Belachew, Manahloh; Tepp, Gabrielle; Keir, Derek; Ayele, Atalay

2014-05-01

252

Shear rupture of a directionally solidified eutectic gamma/gamma-prime - alpha /Mo/ alloy. [for aircraft engine turbine blades  

NASA Technical Reports Server (NTRS)

Directionally solidified gamma/gamma-prime - alpha (Mo) eutectic alloys are being evaluated for application as advanced aircraft engine turbine blades. Their excellent high-temperature strength is partly due to their directionally aligned microstructure. However, alloys with such directional structures may display low shear strength at 760 C, the operating temperature of advanced blade roots. The objective of this investigation was to determine the shear rupture strength of the gamma/gamma-prime - alpha eutectic alloy and possibly to improve it by microstructural and heat-treatment variations. Bars of gamma/gamma-prime - alpha alloy containing nominally 5.7% Al and 33.5% Mo by weight with balance Ni were directionally solidified at rates between 10 and 100 mm per hour. Materials were solidified in furnaces with thermal gradients at the liquid-solid interface of 250 or 100 C per cm. A limited number of longitudinal shear rupture tests were conducted at 760 C and 207 MPa in the as-solidified and in several heat-treated conditions. It was found that the shear rupture failures are partly transgranular and that resistance to failure is promoted by good fiber alignment and a matrix structure consisting mainly of gamma-prime. Well-aligned as-solidified specimens sustained the shear stress for an average of 81 hours, while cellular material failed in one hour or less.

Harf, F. H.

1978-01-01

253

Delamination behaviour of GdBCO coated conductor tapes under transverse tension  

NASA Astrophysics Data System (ADS)

The electromechanical property behaviour of 2G coated conductor (CC) tapes fabricated by multi-layer deposition process both in the in-plane and transverse direction should be understood. The CC tapes are used in the fabrication of epoxy resin-impregnated coils. In such case, the Lorentz force due to the high magnetic field applied as well as the thermal stress due to the difference in coefficient of thermal expansion (CTE) among constituent layers during cooling to cryogenic temperature will induce transversely applied load to the surface of CC tapes in coils. Hence, the CC tape should have a good mechanical property in the transverse direction in order to maintain its superior performance under magnetic field. In this study, a test frame which gives precisely aligned transverse load was devised. Using the fixture, the delamination behaviours including the delamination strength of the GdBCO CC tapes under transverse tensile loading were investigated. Large variation on the delamination strength of the CC tapes was recorded and might have resulted from the slit edge effect and the inhomogeneity of the CC tapes. The Ic degradation behaviour under transverse load was related to the location where delamination occurred in the sample.

Gorospe, A.; Nisay, A.; Dizon, J. R.; Shin, H. S.

2013-11-01

254

Rapid control in ruptured abdominal aneurysms.  

PubMed

Rapid control of a ruptured abdominal aneurysm can be achieved under local anesthesia by passing a Fogarty catheter, 8/22 F, retrograde from either femoral artery up into the thoracic aorta and inflating the balloon after administering heparin to the patient. This method avoids the often fatal hypotension that may occur with induction of general anesthesia in the hypovolemic patient. In cases in which the Fogarty catheter cannot pass up the iliac artery, direct insertion of the catheter through the aneurysm can be used, but this method requires the induction of general anesthesia prior to aortic control. PMID:7259508

Sensenig, D M

1981-08-01

255

Atherosclerotic plaque rupture and thrombosis. Evolving concepts.  

PubMed

Rupture of an atherosclerotic plaque associated with partial or complete thrombotic vessel occlusion is fundamental to the development of ischemic coronary syndromes. Plaques that produce only mild-to-moderate angiographic luminal stenosis are frequently those that undergo abrupt disruption, leading to unstable angina or acute myocardial infarction. Plaques with increased lipid content appear more prone to rupture, particularly when the lipid pool is localized eccentrically within the intima. Macrophages appear to play an important role in atherogenesis, perhaps by participating in the uptake and metabolism of lipoproteins, secretion of growth factors, and production of enzymes and toxic metabolites that may facilitate plaque rupture. In addition, the particular composition or configuration of a plaque and the hemodynamic forces to which it is exposed may determine its susceptibility to disruption. Exposure of collagen, lipids, and smooth muscle cells after plaque rupture leads to the activation of platelets and the coagulation cascade system. The resulting thrombus may lead to marked reduction in myocardial perfusion and the development of an unstable coronary syndrome, or it may become organized and incorporated into the diseased vessel, thus contributing to the progression of atherosclerosis. In unstable angina, plaque disruption leads to thrombosis, which is usually labile and results in only a transient reduction in myocardial perfusion. Release of vasoactive substances, arterial spasm, or increases in myocardial oxygen demand may contribute to ischemia. In acute myocardial infarction, plaque disruption results in a more persistent thrombotic vessel occlusion; the extent of necrosis depends on the size of the artery, the duration of occlusion, the presence of collateral flow, and the integrity of the fibrinolytic system. Thrombi that undergo lysis expose a highly thrombogenic surface to the circulating blood, which has the capacity of activating platelets and the coagulation cascade system and may lead to thrombotic reocclusion. Measurements aimed at reversing the process of atherosclerosis via cholesterol reduction and enhanced high density lipoprotein activity are encouraging. Active research is being focused on the development of new antithrombotic tools, such as inhibitors of thrombin, thromboxane, and serotonin receptor antagonists, and monoclonal antibodies aimed at blocking platelet membrane receptors or adhesive proteins. These compounds may prove useful when immediate and potent inhibition of the hemostatic system is desired. Intensive research is still needed in the areas of pathogenesis and therapeutic intervention in atherosclerosis. PMID:2203564

Fuster, V; Stein, B; Ambrose, J A; Badimon, L; Badimon, J J; Chesebro, J H

1990-09-01

256

Shear rupture of a directionally solidified eutectic gamma/gamma prime - alpha (Mo) alloy  

NASA Technical Reports Server (NTRS)

Directionally solidified Mo alloys are evaluated to determine the shear rupture strength and to possibly improve it by microstructural and heat treatment variations. Bars of the alloy containing nominally 5.7% Al and 33.5% Mo by weight with balance Ni were directionally solidified at rates between 10 and 100 mm per hour in furnaces with thermal gradients at the liquid-solid interface of 250 or 100 C per cm. A limited number of longitudinal shear rupture tests were conducted at 760 C and 207 MPa in the as - solidified and in several heat treated conditions. It is shown that shear rupture failures are partly transgranular and that resistance to failure is prompted by good fiber alignment and a matrix structure consisting mainly of gamma prime. Well aligned as - solidified specimens sustained the shear stress for an average of 81 hours. A simulated coating heat treatment appeared to increase the transformation of gamma to gamma prime and raised the average shear life of aligned specimens to 111 hours. However, heat treatments at 1245 C and especially at 1190 C appeared to be detrimental by causing partial solutioning of the gamma prime, and reducing lives to 47 and 10 hours, respectively.

Harf, F. H.

1978-01-01

257

A Critique of a Phenomenological Fiber Breakage Model for Stress Rupture of Composite Materials  

NASA Technical Reports Server (NTRS)

Stress rupture is not a critical failure mode for most composite structures, but there are a few applications where it can be critical. One application where stress rupture can be a critical design issue is in Composite Overwrapped Pressure Vessels (COPV's), where the composite material is highly and uniformly loaded for long periods of time and where very high reliability is required. COPV's are normally required to be proof loaded before being put into service to insure strength, but it is feared that the proof load may cause damage that reduces the stress rupture reliability. Recently, a fiber breakage model was proposed specifically to estimate a reduced reliability due to proof loading. The fiber breakage model attempts to model physics believed to occur at the microscopic scale, but validation of the model has not occurred. In this paper, the fiber breakage model is re-derived while highlighting assumptions that were made during the derivation. Some of the assumptions are examined to assess their effect on the final predicted reliability.

Reeder, James R.

2010-01-01

258

Ruptured abdominal aortic aneurysm presenting as buttock pain.  

PubMed

This is the first case report of a ruptured aortic aneurysm presenting with acute right buttock pain. The patient was an 80 year old man. A literature search revealed one report of ruptured internal iliac artery aneurysm presenting with acute hip pain and another of an unruptured aortic aneurysm presenting with chronic hip pain. Thus the present case is another unusual presentation of ruptured abdominal aortic aneurysm and highlights the importance of careful history taking and clinical examination. A high index of clinical suspicion of aneurysm rupture should be maintained in elderly patients presenting with a history of collapse. PMID:15911962

Mahmood, F; Ahsan, F; Hockey, M

2005-06-01

259

The Modulus of Rupture from a Mathematical Point of View  

NASA Astrophysics Data System (ADS)

The goal of this work is to present a complete mathematical study about the three-point bending experiments and the modulus of rupture of brittle materials. We will present the mathematical model associated to three-point bending experiments and we will use the asymptotic expansion method to obtain a new formula to calculate the modulus of rupture. We will compare the modulus of rupture of porcelain obtained with the previous formula with that obtained by using the classic theoretical formula. Finally, we will also present one and three-dimensional numerical simulations to compute the modulus of rupture.

Quintela, P.; S醤chez, M. T.

2007-04-01

260

Role of transverse bulkheads in hull stiffness of large container ships  

Microsoft Academic Search

Ultra large container ships are rather flexible and exposed to significant wave deformations. Therefore, hydroelastic strength analysis is required for these types of ships. Coupling of beam structural model and 3D hydrodynamic model is preferable for the reason of simplicity. In this paper, the contribution of a large number of transverse bulkheads to general hull stiffness is analysed. The prismatic

Ivo Senjanovi?; Stipe Toma歟vi?; Smiljko Rudan; Tanja Senjanovi?

2008-01-01

261

Investigating Earthquake Rupture Processes in a Deep South African Gold Mine (Invited)  

NASA Astrophysics Data System (ADS)

A primary objective of the NELSAM (Natural Earthquake Laboratory in South African Mines) Project was to record the rupture processes in the near field of a mining-induced earthquake of M>3. When this project was initiated, it seemed likely that an earthquake this large would rupture the ancient Pretorius fault where it intersected the gold-bearing reef at a depth of 3600 m, near the bottom of TauTona Mine. To prepare, a small-scale network of borehole seismic and strain instrumentation was installed. Also, much effort was expended in geologic investigations in the immediate environs of the portion of the Pretorius fault where earthquake rupture was expected. Contrary to expectations, the M>3, earthquake never occurred, at least as of this writing. Nonetheless, this project has provided many insights regarding earthquake ruptures because of an opportunity that came up during the initial field investigations of the Pretorius fault. That is, a M2.2 earthquake ruptured the Pretorius fault in December 2004, before the NELSAM borehole instrumentation was installed. This earthquake was, however, well recorded by the mine-wide seismic network and so these seismograms, together with the extensive mapping of the rupture within the Pretorius fault zone, have enhanced considerably our understanding of earthquake source processes and the conditions causing an earthquake. The initial field studies revealed that the Pretorius fault is about 10 km long and dips nearly vertically, on average, with oblique slip up to 200 m. This slip occurred more than 2 billion years ago during the Archean. In the meantime, the Pretorius fault has been inactive until affected by mining operations. This extensive period of inactivity has allowed the fault zone material to recover much of its initial strength; thus, rupture across this fault is probably more like fresh rock fracture than frictional slip. After the M2.2 earthquake in December 2004, a comprehensive study of its effects on the Pretorius fault revealed oblique-normal slip across four non-parallel segments of the fault zone, with a maximum observed slip of 25 mm. The ambient state of stress measured in the environs of this study area is extensional with a vertically oriented, maximum principal stress due to the overburden that is about twice the minimum horizontal principal stress. These ambient stresses were altered substantially by the nearby mining so as to induce this M2.2 earthquake. Analysis of the ground motion data from the mine-wide seismic network indicated a seismic moment tensor with a shear component of 2.3e12 N-m as well as an implosive component, associated with coseismic collapse of the nearby mine stopes. Laboratory rock mechanics results were used to interpret the seismic moment and the maximum slip to infer a failure stress in the seismogenic zone of about 120 MPa. This high failure stress is consistent with the strength of the Pretorius fault zone material measured in the laboratory as well as with the radiated energy, 5.4e8 J, which is quite high for an earthquake of M2.2. In short, the rupture zone of this well-recorded earthquake was studied in detail to reveal many important insights concerning the source mechanics of earthquakes.

McGarr, A.; Fletcher, J. B.; Boettcher, M. S.; Heesakkers, V.; Johnston, M. J.; Reches, Z.

2010-12-01

262

Insight into the rupture process of a rare tsunami earthquake from near-field high-rate GPS  

NASA Astrophysics Data System (ADS)

We investigated the rupture duration and velocity of the October 25, 2010 Mentawai earthquake by examining high-rate GPS displacement data. This Mw=7.8 earthquake appears to have ruptured either an up-dip part of the Sumatran megathrust or a fore-arc splay fault, and produced tsunami run-ups on nearby islands that were out of proportion with its magnitude. It has been described as a so-called "slow tsunami earthquake", characterised by a dearth of high-frequency signal and long rupture duration in low-strength, near-surface media. The event was recorded by the Sumatran GPS Array (SuGAr), a network of high-rate (1 sec) GPS sensors located on the nearby islands of the Sumatran fore-arc. For this study, the 1 sec time series from 8 SuGAr stations were selected for analysis due to their proximity to the source and high-quality recordings of both static displacements and dynamic waveforms induced by surface waves. The stations are located at epicentral distances of between 50 and 210 km, providing a unique opportunity to observe the dynamic source processes of a tsunami earthquake from near-source, high-rate GPS. We estimated the rupture duration and velocity by simulating the rupture using the spectral finite-element method SPECFEM and comparing the synthetic time series to the observed surface waves. A slip model from a previous study, derived from the inversion of GPS static offsets and tsunami data, and the CRUST2.0 3D velocity model were used as inputs for the simulations. Rupture duration and velocity were varied for a suite of simulations in order to determine the parameters that produce the best-fitting waveforms.

Macpherson, K. A.; Hill, E. M.; Elosegui, P.; Banerjee, P.; Sieh, K. E.

2011-12-01

263

Transverse flux induction heating of aluminum alloy strip  

NASA Astrophysics Data System (ADS)

Transverse flux induction heating, an efficient electrical technique particularly suited to the continuous heat treatment of metal strip, is explained. Also described is a 1MW transverse flux inductor designed and built at the Electricity Council Research Centre, Capenhurst, and installed in a tension leveller line at Alcan Plate Ltd., Birmingham, UK. It has been successfully used for the continuous heat treatment of wide (1200-1250 mm) aluminum alloy strip, involving full and partial annealing at line speeds up to 2/ms as well as the solution treatment of certain high strength aluminum alloys. The advantages of this form of induction heating are compactness, controllability, hence ease of automation, and high efficiency. As a consequence, compared with existing batch and continuous heat treatment equipment, major economies in plant operation result due to reduced energy consumption as well as reduced capital and labor costs. The compactness of the technique allows the possibility of introducing transverse flux induction heat treatment furnaces into existing process lines.

Waggott, R.; Walker, D. J.; Gibson, R. C.; Johnson, R. C.

1981-07-01

264

Transversity $K$ Factors for Drell-Yan  

E-print Network

The question of the $K$ factor in transversely polarised Drell-Yan (DY) processes is examined. The transverse-spin case is peculiar for the absence of a reference point in deeply inelastic scattering (DIS). A DIS definition for transversity is therefore devised using a hypothetical scalar (Higgs-like) vertex, in order to study more fully the possible effects of higher-order corrections on DY asymmetries. The results show that some care may be required in interpreting experimentally extracted partonic transversity, in particular when comparing with model calculations or predictions.

Ratcliffe, P G

2004-01-01

265

Rupture history of the 2008 Mw 7.9 Wenchuan, China, earthquake: Evaluation of separate and joint inversions of geodetic, teleseismic, and strong-motion data  

USGS Publications Warehouse

earthquake. A linear multiple-time-window approach is used to parameterize the rupture. Because of the complexity of the Wenchuan faulting, three separate planes are used to represent the rupturing surfaces. This earthquake clearly demonstrates the strengths and limitations of geodetic, teleseismic, and strong-motion data sets. Geodetic data (static offsets) are valuable for determining the distribution of shallower slip but are insensitive to deeper faulting and reveal nothing about the timing of slip. Teleseismic data in the distance range 30皷90 generally involve no modeling difficulties because of simple ray paths and can distinguish shallow from deep slip. Teleseismic data, however, cannot distinguish between different slip scenarios when multiple fault planes are involved because steep takeoff angles lead to ambiguity in timing. Local strong-motion data, on the other hand, are ideal for determining the direction of rupture from directivity but can easily be over modeled with inaccurate Green抯 functions, leading to misinterpretation of the slip distribution. We show that all three data sets are required to give an accurate description of the Wenchuan rupture. The moment is estimated to be approximately 1:01021 N m with the slip characterized by multiple large patches with slips up to 10 m. Rupture initiates on the southern end of the Pengguan fault and proceeds unilaterally to the northeast. Upon reaching the cross-cutting Xiaoyudong fault, rupture of the adjacent Beichuan fault starts at this juncture and proceeds bilaterally to the northeast and southwest.

Hartzell, Stephen; Mendoza, Carlos; Ram韗ez-Guzm醤, Leonardo; Zeng, Yuesha; Mooney, Walter

2013-01-01

266

Poxvirus membrane biogenesis: rupture not disruption  

PubMed Central

Summary Enveloped viruses acquire their membrane from the host by budding at, or wrapping by, cellular membranes. Transmission electron microscopy (TEM) images, however, suggested that the prototype member of the poxviridae, vaccinia virus (VACV), may create its membrane 慸e novo with free open ends exposed in the cytosol. Within the frame of the German-wide priority programme we re-addressed the biogenesis and origin of the VACV membrane using electron tomography (ET), cryo-EM and lipid analysis of purified VACV using mass spectrometry (MS). This review discussed how our data led to a model of unconventional membrane biogenesis involving membrane rupture and the generation of a single open membrane from open membrane intermediates. Lipid analyses of purified virus by MS suggest an ER origin with a relatively low cholesterol content compared with whole cells, confirming published data. Unlike previous reports using thin-layer chromatography, no depletion of phosphatidylethanolamine was detected. We did detect, however, an enrichment for phosphatidic acid, diacylglycerol and phosphatidylinositol in the virion. Our data are discussed in the light of other pathogens that may require cellular membrane rupture during their intracellular life cycle. PMID:23168015

Locker, Jacomine Krijnse; Chlanda, Petr; Sachsenheimer, Timo; Brugger, Britta

2014-01-01

267

TMI-2 lower head creep rupture analysis  

SciTech Connect

The TMI-2 accident resulted in approximately 40% of the reactor's core melting and collecting on the lower head of the reactor pressure vessel. The severity of the accident has raised questions about the margin of safety against rupture of the lower head in this accident since all evidence seems to indicate no major breach of the vessel occurred. Scoping heat transfer analyses of the relocated core debris and lower head have been made based upon assumed core melting scenarios and core material debris formations while in contact with the lower head. This report describes the structural finite element creep rupture analysis of the lower head using a temperature transient judged most likely to challenge the structural capacity of the vessel. This evaluation of vessel response to this transient has provided insight into the creep mechanisms of the vessel wall, a realistic mode of failure, and a means by which margin to failure can be evaluated once examination provides estimated maximum wall temperatures. Suggestions for more extensive research in this area are also provided. 6 refs., 15 figs.

Thinnes, G.L.

1988-08-01

268

[Surgical consideration of ruptured abdominal aortic aneurysms].  

PubMed

During the recent 18 and a half years, 30 cases of ruptured abdominal aortic aneurysm (including four cases of A-V fistula) were operated at Saiseikai Utsunomiya Hospital. In 26 cases, a conventional graft replacement was performed. In other four cases, axillo-bifemoral bypass (in the cases ruptured into the colon) or other methods were used. Overall operative mortality rate was 26.7%. However, during the last 9 years, operative results were improved (21.7%, 5 deaths out of 23 cases). Amount of intraoperative blood loss influenced the operative results greatly. Other operative risk factors included preoperative shock, preoperative severe cerebrovascular or cardiovascular complications, and postoperative thromboembolism. Factors of recent improvement in mortality included; establishment of emergency system which resulted in earlier operation after the patient's arrival at the hospital, use of occlusive balloon for bleeding control, heparin administration before the aortic clamp for preventing peripheral thromboembolism and introduction of autotransfusion system for reducing the amount of blood transfusion. PMID:2770687

Kiso, I; Yozu, R; Maehara, T; Umezu, Y; Hirotani, T; Ishikura, Y; Takeuchi, S

1989-03-01

269

Management of extensor mechanism rupture after TKA.  

PubMed

Disruption of the extensor mechanism in total knee arthroplasty may occur by tubercle avulsion, patellar or quadriceps tendon rupture, or patella fracture, and whether occurring intra-operatively or post-operatively can be difficult to manage and is associated with a significant rate of failure and associated complications. This surgery is frequently performed in compromised tissues, and repairs must frequently be protected with cerclage wiring and/or augmentation with local tendon (semi-tendinosis, gracilis) which may also be used to treat soft-tissue loss in the face of chronic disruption. Quadriceps rupture may be treated with conservative therapy if the patient retains active extension. Component loosening or loss of active extension of 20 or greater are clear indications for surgical treatment of patellar fracture. Acute patellar tendon disruption may be treated by primary repair. Chronic extensor failure is often complicated by tissue loss and retraction can be treated with medial gastrocnemius flaps, achilles tendon allografts, and complete extensor mechanism allografts. Attention to fixing the graft in full extension is mandatory to prevent severe extensor lag as the graft stretches out over time. PMID:23118397

Rosenberg, A G

2012-11-01

270

[Traumatic rupture of the descending aorta].  

PubMed

During a ten-year period 16 patients were seen with aortic rupture and false aneurysm secondary to blunt trauma. One patient underwent an acute operation, 4 patients had operative therapy elective delayed and 11 patients were operated on for chronic traumatic false aneurysm. Operative delay was done in case of simultaneous multisystem injury (e.g. shock caused by abdominal injuries, cerebral contusion or pulmonary contusion on the right side). The shunt bypass method of repair was used in the case of 3 patients, cardiopulmonary bypass in 6 cases and simple aortic cross-clamping in 6 patients. One operation was performed without aortic cross-clamping. Primary repair was achieved in three patient, in 3 more cases a patch was inserted and in 9 cases interposition Dacron grafting was accomplished. One "wrapping" operation was performed. In 2 cases, reoperation was necessary because of postoperative bleeding. One patient died in the perioperative period. Right sided hemiparesis occurred in one patient postoperatively. Rupture does not affect the whole aortic wall, especially in young people because of the natural elasticity of vessel. The appearing shock and hypotension might protect the mediastinal pleura against bursting. This could provide a chance to survive. Our experience indicate: Elective delay of operation in patients with multiple system injuries can be achieved with antihypertensive therapy. PMID:9380385

Kov醕s, E; Dzsinich, C; Gy鰊gy, T; Moravcsik, E; Szabolcs, Z; Bodor, E

1997-09-28

271

[Spontaneous rupture of the spleen disclosing pheochromocytoma].  

PubMed

The authors report a case of spontaneous rupture of spleen inaugurating the symptomatology of a pheochromocytoma. After presenting the observation, clinical problems are considered with a deceptive abdominal symptomatology and myocardial ischemia that could be part of an "adrenergic myocarditis"; the mechanism of ruptured spleen is analyzed. The diagnosis approach is discussed through a reliability study of various explorations: computed tomography has a sensitivity ranging from 93 to 97% which approaches 100% when associated with magnetic resonance, methyl-iodo-benzyl-guanidine scanning seems to be provided with similar reliability. During checking up for pheochromocytoma spreading, ectopic location was not found, but a cold thyroid nodule was detected which allowed suspecting a SIPPLE syndrome. The three-stage surgical approach was required by symptomatology, hemostasis splenectomy, lateral pheochromocytoma excision after a short preparation by blocking alpha and beta, and then total thyroidectomy after extemporaneous confirmation of the existence of a medullary carcinoma of the thyroid. This pathologic association leading to a SIPPLE syndrome is listed as part of the multiple endocrine neoplasias of type II (MEN II). PMID:2262521

Carles, J; Guegan, H; Crozat, T; Janvier, G; Riant, T; Videau, J

1990-10-01

272

GPU Acceleration of Support Operator Rupture Dynamics  

NASA Astrophysics Data System (ADS)

SORD (Support Operator Rupture Dynamics) is an open-source software based on a fourth-order finite-difference method which can simulate 3D elastic wave propagation and spontaneous rupture on hexahedral mesh. It can be used for many kinds of surface boundary conditions, including free surface. The original software is developed by Geoffrey Ely from USC and modified by us for acceleration on GPU with NVIDIA CUDA. Our motivation on accelerating SORD on GPU is inspired by new generation GPU抯 superior ability on general purpose computing and NVIDIA CUDA抯 user-friendly developing environment for academic users. After translating the code from Fortran 95 to CUDA and implementing the transformed CUDA SORD code on the NVIDIA Tesla C1060, we obtained a factor of 6 speedup as compared to the original Fortran 95 version code , which was run on Intel Xeon X5570 2.9GHz. Our 3D wave solutions show explicitly visually in 3D format the different propagating wave fronts associated with the P and S waves according to the appropriate elastic parameter ratios. Because of the limitation of the global memory of NVIDIA Tesla C1060, too many more grid points would slow the calculation. However, by using the new NVIDIA Tesla C2070, which has 6 GBytes global memory, we can increase the simulation data size into 350X350X350.

Zhou, Y.; Dong, T.; Yuen, D. A.

2010-12-01

273

Short-term mechanical properties of high-strength light-weight concrete  

NASA Astrophysics Data System (ADS)

An experimental investigation was undertaken to establish the mechanical properties of high-strength light-weight concrete. Concretes having compressive strengths ranging from 2,564 to 8,585 psi, and densities between 90 and 103 pcf were tested. The results include a comprehensive study of the engineering properties of light-weight concrete. Data are presented on compressive strength gain with age, speciment size effect, static modulus of elasticity, Poisson's ratio, modulus of rupture, splitting tensile strength, and drying effects. Results are compared to data on normal-weight concrete. The deformation characteristics of light-weight concrete are studied in detail.

Morales, S. M.

1982-08-01

274

The effect of electron beam welding on the creep rupture properties of a Nb-Zr-C alloy  

NASA Technical Reports Server (NTRS)

Creep rupture tests of electron beam welded PWC-11 sheet were conducted at 1350 K. Full penetration, single pass welds were oriented transverse to the testing direction in 1 mm thick sheet. With this orientation, stress was imposed equally on the base metal, weld metal, and heat-affected zone. Tests were conducted in both the postweld annealed and aged conditions. Unwelded specimens with similar heat treatments were tested for comparative purposes. It was found that the weld region is stronger than the base metal for both the annealed and aged conditions and that the PWC-11 material is stronger in the annealed condition than in the aged condition.

Moore, T. J.; Titran, R. H.; Grobstein, T. L.

1986-01-01

275

TRANSLATIONAL STRENGTHS AT  

E-print Network

TRANSLATIONAL STRENGTHS AT OHSU 2 0 1 3 Translational Strengths at OHSU (STINT) Conducted;2 OregOnCliniCalandTranslaTiOnalresearChinsTiTuTe ExEcutivE Summary Strengths in Translation at OHSU (STINT) In Spring of 2013, the OCTRI Office of Research Impact interviewed 51 OHSU translational

Chapman, Michael S.

276

Development of a high strength hot isostatically pressed /HIP/ disk alloy, MERL 76  

NASA Technical Reports Server (NTRS)

A nickel-based powder metal disk alloy developed for use in advanced commercial gas turbines is described. Consideration is given to final alloy chemistry modifications made to achieve a desirable balance between tensile strength and stress rupture life and ductility. The effects of post-consolidation heat treatment are discussed, the preliminary mechanical properties obtained from full-scale turbine disks are presented.

Evans, D. J.; Eng, R. D.

1980-01-01

277

The relationship between knee strength and functional stability before and after anterior cruciate ligament reconstruction  

Microsoft Academic Search

Functional stability of the knee is dependent on an intact ligamentous system and the timely and efficient contraction of supporting musculature. The aim of this study was to assess the relationship between muscle strength and functional stability in 31 patients pre- and post-operatively, following a unilateral anterior cruciate ligament rupture. All subjects underwent reconstructive surgery using semitendonosis and gracilis tendons.

S. L. Keays; J. E. Bullock-Saxton; P. Newcombe; A. C. Keays

2003-01-01

278

Transverse spin and transverse momentum structure of the nucleon from the COMPASS experiment  

E-print Network

A selection is presented of recent results from the COMPASS Collaboration on transverse spin and transverse momentum effects in semi-inclusive deeply inelastic scattering (SIDIS) of 160 GeV/c muons off proton and deuteron targets.

Bradamante, F

2014-01-01

279

Transverse spin and transverse momentum structure of the nucleon from the COMPASS experiment  

E-print Network

A selection is presented of recent results from the COMPASS Collaboration on transverse spin and transverse momentum effects in semi-inclusive deeply inelastic scattering (SIDIS) of 160 GeV/c muons off proton and deuteron targets.

F. Bradamante

2014-01-24

280

Ruptured abdominal aortic aneurysm presenting as buttock pain  

Microsoft Academic Search

This is the first case report of a ruptured aortic aneurysm presenting with acute right buttock pain. The patient was an 80 year old man. A literature search revealed one report of ruptured internal iliac artery aneurysm presenting with acute hip pain and another of an unruptured aortic aneurysm presenting with chronic hip pain. Thus the present case is another

F Mahmood; F Ahsan; M Hockey

2005-01-01

281

The resolution of ruptures in the therapeutic alliance  

Microsoft Academic Search

This article outlines some of the main features of a research program on ruptures in the therapeutic alliance and reports some of the major findings to date. A rupture in the therapeutic alliance is a deterioration in the quality of the relationship between patient and therapist; it is an interpersonal marker that indicates a critical opportunity for exploring and understanding

Jeremy D. Safran; J. Christopher Muran

1996-01-01

282

The Resolution of Ruptures in the Therapeutic Alliance.  

ERIC Educational Resources Information Center

A rupture in the therapeutic alliance is a deterioration in the quality of the relationship between patient and therapist; it is an interpersonal marker that indicates an opportunity for exploring and understanding the processes that maintain a maladaptive interpersonal schema. Outlines features of a research program on ruptures in the therapeutic

Safran, Jeremy D.; Muran, J. Christopher

1996-01-01

283

Rupture of major bronchi resulting from closed chest injuries  

PubMed Central

Four cases of ruptured bronchus following closed chest trauma are described. All injuries resulted from motor vehicle accidents and were diagnosed and treated within 24 hours of admission to the hospital. A satisfactory result followed early suture repair of the ruptured bronchus in three cases. One patient died during pneumonectomy. The early diagnosis and treatment of the condition are discussed. Images PMID:4724503

Collins, John P.; Ketharanathan, V.; McConchie, Ian

1973-01-01

284

Vaginal birth after cesarean and uterine rupture rates in California  

Microsoft Academic Search

Objective: To describe attempted and successful vaginal birth after cesarean (VBAC) rates and uterine rupture rates for women with and without prior cesareans, and compare delivery outcomes in hospitals with different attempted VBAC rates.Methods: We used California hospital discharge summary data for 1995 to calculate attempted and successful VBAC rates and uterine rupture rates. We used multivariate logistic regression models

Kimberly D Gregory; Lisa M Korst; Patricia Cane; Lawrence D Platt; Katherine Kahn

1999-01-01

285

Non-bleeding Spontaneous Rupture of Hepatocellular Carcinoma.  

PubMed

Rupture of hepatocellular carcinoma (HCC) is not uncommon and most ruptured HCC present with hemoperitoneum and hemorrhagic shock. Management of ruptured HCC is different than non-ruptured one. Short- and long-term mortality increases following rupture of HCC with increasing chances of tumor dissemination. We describe a case with non-bleeding spontaneous rupture of HCC. A 62-year-old male patient was admitted to our institute hospital with mild to moderate pain in the right upper part of the abdomen. He lost appetite and weight. Ultrasonography of the abdomen was performed and it suggested HCC and ascites. Triple phase computer tomography revealed HCC in segments 6 and 7 of liver with typical radiological characteristics. Portal vein was thrombosed. No extravasation of dye was seen. Ruptured of tumor through liver capsule was seen with necrosis and hemorrhage in the center of the tumor. Non-bleeding ruptured HCC has not been reported in the literature to the best of our knowledge. We herein describe this rare case. PMID:24497757

Islam, Mahibul; Deka, Pranjal; Kapur, Raj; Ansari, Md Abu Masud

2013-07-01

286

Successful Patching of Iatrogenic Rupture of the Fetal Membranes  

Microsoft Academic Search

Rupture of the fetal membranes is a common, but potentially serious complication of invasive fetal procedures. Quintero described a technique to seal the fetal membrane defect by means of a bloodpatch, usually called 慳mniopatch in this application. The successful use in two consecutive patients with ruptured membranes after a fetoscopic intervention at respectively 17 and 22 weeks' gestational age is

L Lewi; D Van Schoubroeck; M Van Ranst; G Bries; M-P Emonds; B Arabin; R Welch; J Deprest

2004-01-01

287

Survivors of ruptured abdominal aortic aneurysm: the iceberg's tip  

Microsoft Academic Search

In four and a half years 25 patients in one community suffered a ruptured abdominal aortic aneurysm. Eleven died at home, nine died without operation in hospital, and only five had the aneurysm removed. There were four survivors. A further seven patients might have lived had they had a prompt operation. The average operative mortality for ruptured aneurysms among series

R H Armour

1977-01-01

288

Effects of Porosity on Strength of Carbon-Carbon Composites  

Microsoft Academic Search

Filament wound\\/CVD (Chemical Vapor Deposition) carbon-carbon composites have received considerable attention and application within the past few years because of their desirable characteristics such as high heat of ablation, thermal shock resistance, high strength at elevated temperatures, and chemical inertness. However, poor mechanical properties in the transverse direction have hampered the total effectiveness of these composites in some applications and

Gilbert William Brassell; James A. Horak; Barry Lynn Butler

1975-01-01

289

Transverse instability at the recycler ring  

SciTech Connect

Sporadic transverse instabilities have been observed at the Fermilab Recycler Ring leading to increase in transverse emittances and beam loss. The driving source of these instabilities has been attributed to the resistive-wall impedance with space-charge playing an important role in suppressing Landau damping. Growth rates of the instabilities are computed. Remaining problems are discussed.

Ng, K.Y.; /Fermilab

2004-10-01

290

Transverse polarization in triglycine sulphate ferroelectric  

NASA Astrophysics Data System (ADS)

The results of measurements of the electric current's density along the non-polar c-axis direction in the triglycine sulphate ferroelectric have been shown. The pyroelectric properties have been observed in the same direction. Evidence of the occurrence of crystal's temperature-dependent transverse polarization has been given. A strong correlation between the transverse and longitudinal polarizations has been found out.

Fugiel, B.

2002-05-01

291

Single-Spin Asymmetries and Transversity  

NASA Astrophysics Data System (ADS)

A pedagogical introduction to single-spin asymmetries (SSA's) and transversity is presented. Discussion in some detail is made of certain aspects of SSA's in lepton-nucleon and in hadron-hadron scattering and the role of pQCD and evolution in the context of transversity.

Ratcliffe, Philip G.

2003-07-01

292

Single-Spin Asymmetries and Transversity  

E-print Network

A pedagogical introduction to single-spin asymmetries (SSA's) and transversity is presented. Discussion in some detail is made of certain aspects of (SSA's) in lepton-nucleon and in hadron-hadron scattering and the role of pQCD and evolution in the context of transversity.

Ratcliffe, P G

2002-01-01

293

Distal biceps tendon rupture reconstruction using muscle-splitting double-incision approach  

PubMed Central

AIM: To evaluate the clinical and functional results after repair of distal biceps tendon tears, following the Morrey抯 modified double-incision approach. METHODS: We retrospectively reviewed 47 patients with distal rupture of biceps brachii treated between 2003 and 2012 in our Orthopedic Department with muscle-splitting double-incision technique. Outcome measures included the Mayo elbow performance, the DASH questionnaire, patient抯 satisfaction, elbow and forearm motion, grip strength and complications occurrence. RESULTS: At an average 18 mo follow-up (range, 7 mo-10 years) the average Mayo elbow performance and DASH score were respectively 97.2 and 4.8. The elbow flexion range was 94%, extension was -2, supination was 93% and pronation 96% compared with the uninjured limb. The mean grip strength, expressed as percentage of respective contralateral limb, was 83%. The average patient satisfaction rating on a Likert scale (from 0 to 10) was 9.4. The following complications were observed: 3 cases of heterotopic ossification (6.4%), one (2.1%) re-rupture of the tendon at the site of reattachment and 2 cases (4.3%) of posterior interosseous nerve palsy. No complication required further surgical treatment. CONCLUSION: This technique allows an anatomic reattachment of distal biceps tendon at the radial tuberosity providing full functional recovery with low complication rate. PMID:25133147

Tarallo, Luigi; Mugnai, Raffaele; Zambianchi, Francesco; Adani, Roberto; Catani, Fabio

2014-01-01

294

Do All Large Strike-slip Earthquakes Have Supershear Ruptures?  

NASA Astrophysics Data System (ADS)

Studying the rupture speeds of earthquakes is of broad interesting for earthquake research because it has a large effect on the strong near-field shaking that causes damage during earthquakes. Also rupture speed is a key observation for understanding the controlling stresses and friction during an earthquake, yet the speed and its variations are usually difficult to determine. Using only far-field seismic waveforms, which is the only data available for many large earthquakes, there are problems for estimating the rupture speed with standard waveform inversions, due to trade-off between the rupture speed and the slip location. Here we applied a back projection method to estimate the rupture speeds of Mw ? 7.5 strike-slip earthquakes since 2001 which could be analyzed using Hi-net in Japan. We found that all events had very fast average rupture speeds of 3.0-6.0 km/s, which are near or greater than the local shear wave velocity (supershear). These values are faster than for thrust and normal faulting earthquakes that generally rupture with speeds of 1.0-3.0 km/s. Considering the depth-dependent shear-wave velocity, the average propagation speeds for all of the strike-slip events are closer to or greater than the shear wave velocity (Figure 1). For large strike-slip events, transition from subshear to supershear usually occurs within distances of 15 to 30 km from the initiation, which is probably the reason for the scarcity of observed supershear earthquakes for smaller magnitudes. Earthquakes with supershear ruptures can cause more damage than events with subshear ruptures because of the concentration of energy in the forward direction of the rupture. Numerical modeling shows strong focusing and other effects of energy at the rupture front which can intensify the ground motions. A recent example is the April 13, 2010 Qinghai, China earthquake (Mw 6.9), where a moderate-size event caused extensive damage in the Yushu region at the southeastern end of the fault. Careful evaluation of long and straight strike-slip faults should be emphasized for predicting strong ground motions due to supershear rupture. a: Average rupture speeds for Mw ? 7.5 strike-slip earthquakes. For comparison, dip-slip earthquakes are also shown. The blue dashed line presents the S wave velocity model of PREM for comparison. b: Rupture velocities are shown as ratio to the local S wave velocity, as a function of depth.

Wang, D.; Mori, J. J.; Koketsu, K.

2013-12-01

295

Rupture of Right Hepatic Duct into Hydatid Cyst  

PubMed Central

Echinococcal disease can develop anywhere in the human body. The liver represents its most frequent location. Hepatic hydatid cysts may rupture into the biliary tract, thorax, peritoneum, viscera, digestive tract or skin. We report a rare case with rupture of the right hepatic duct into a hydatid cyst in a woman with known hydatid disease and choledocholithiasis. The increased intra-luminal pressure in the biliary tree caused the rupture into the adjacent hydatid cyst. The creation of the fistula between the right hepatic duct and the hydatid cyst decompressed the biliary tree, decreased the bilirubin levels and offered a temporary resolution of the obstructive jaundice. Rupture of a hydatid cyst into the biliary tree usually leads to biliary colic, cholangitis and jaundice. However, in case of obstructive jaundice due to choledocholithiasis, it is possible that the cyst may rupture by other way around while offering the patient a temporary relief from his symptoms. PMID:22876065

Laskou, Styliani; Papavramidis, Theodossis S.; Pliakos, Ioannis; Kotidis, Eustathios; Kesisoglou, Isaak; Papavramidis, Spiros T.

2012-01-01

296

Malignant fibrous histiocytoma presenting as hemoperitoneum mimicking hepatocellular carcinoma rupture  

PubMed Central

Malignant fibrous histiocytoma (MFH) is a pleomorphic mesenchynal sarcoma. It is uncommonly arises primarily from the intra-peritoneal cavity. Primary peritoneal MFH with tumor bleeding and rupture is rare. We describe the imaging features of a 70-year-old patient presenting with ruptured hemorrhagic peritoneal MFH at subhepatic area, accompanied by massive hemoperitoneum, mimicking a ruptured pedunculated hepatocellular carcinoma. Computed tomography (CT) revealed a large heterogeneous enhanced subhepatic mass with adjacent liver, gallbladder and colon invasion. Tumor hemorrhage and rupture complicated with peritoneal seeding and massive bloody ascites were also detected. Angiography showed a hypervascular tumor fed by enlarged right hepatic arteries, cystic artery and omental branches of gastroepiploic artery. The patient underwent laparotomy for tumor resection, but the tumor recurred one month after operation. To our knowledge, the CT appearance of ruptured intraperitoneal MFH complicated by hemoperitoneum has not been previously described. PMID:18081238

Chen, Hsin-Chi; Chen, Chi-Jen; Jeng, Chin-Ming; Yang, Chan-Ming

2007-01-01

297

Macroscopic Source Properties from Dynamic Rupture Styles in Plastic Media  

NASA Astrophysics Data System (ADS)

High stress concentrations at earthquake rupture fronts may generate an inelastic off-fault response at the rupture tip, leading to increased energy absorption in the damage zone. Furthermore, the induced asymmetric plastic strain field in in-plane rupture modes may produce bimaterial interfaces that can increase radiation efficiency and reduce frictional dissipation. Off-fault inelasticity thus plays an important role for realistic predictions of near-fault ground motion. Guided by our previous studies in the 2D elastic case, we perform rupture dynamics simulations including rate-and-state friction and off-fault plasticity to investigate the effects on the rupture properties. We quantitatively analyze macroscopic source properties for different rupture styles, ranging from cracks to pulses and subshear to supershear ruptures, and their transitional mechanisms. The energy dissipation due to off-fault inelasticity modifies the conditions to obtain each rupture style and alters macroscopic source properties. We examine apparent fracture energy, rupture and healing front speed, peak slip and peak slip velocity, dynamic stress drop and size of the process and plastic zones, slip and plastic seismic moment, and their connection to ground motion. This presentation focuses on the effects of rupture style and off-fault plasticity on the resulting ground motion patterns, especially on characteristic slip velocity function signatures and resulting seismic moments. We aim at developing scaling rules for equivalent elastic models, as function of background stress and frictional parameters, that may lead to improved "pseudo-dynamic" source parameterizations for ground-motion calculation. Moreover, our simulations provide quantitative relations between off-fault energy dissipation and macroscopic source properties. These relations might provide a self-consistent theoretical framework for the study of the earthquake energy balance based on observable earthquake source parameters.

Gabriel, A.; Ampuero, J. P.; Dalguer, L. A.; Mai, P. M.

2011-12-01

298

Imaging Atherosclerosis and Risk of Plaque Rupture  

PubMed Central

Atherosclerosis imaging strategies can delineate characteristics of plaques at risk of rupture and thrombosis. Structural plaque imaging identifies high-risk plaque features including lipid pools, thin fibrous caps, and intraplaque hemorrhage, among others. New molecular imaging techniques complement structural imaging approaches by illuminating important features of plaque biology, with a prominent focus on detecting inflammation as a high-risk phenotype. As we unravel the molecular and structural characteristics underlying thrombosis-prone plaques, there is significant promise for eventual early identification and prediction of atherosclerotic plaque complications before they occur. Here we focus on recent imaging insights into high-risk arterial plaques, the etiologic agent of acute myocardial infarction (MI), stroke, and sudden cardiac death. PMID:23982263

Osborn, Eric A; Jaffer, Farouc A

2013-01-01

299

A novel indirect tensile test method to measure the biaxial tensile strength of concretes and other quasibrittle materials  

SciTech Connect

A novel indirect tensile test method, the biaxial flexure test (BFT) method, has been developed to measure the biaxial tensile strength of concretes. The classical modulus of rupture (MOR) test has been generalized to three dimensions. In this method, we use a circular plate as the new test specimen. This plate is supported by an annular ring. We apply an external load to this specimen through a circular edge. The centers of the specimen, the loading device and the support are identical. The biaxial tensile strength measured by this new method is about 19% greater than the uniaxial tensile strength obtained from the classical modulus of rupture test as reported by other researchers. However, at the same time, we also found that the stochastic deviation of the biaxial tensile strength is about 63% greater than the uniaxial strength.

Zi, Goangseup [Department of Civil, Environmental and Architectural Engineering, Korea, University, 5 Ga 1, An-Am Dong, Sung-Buk Gu, Seoul, 136-701 (Korea, Republic of)], E-mail: g-zi@korea.ac.kr; Oh, Hongseob [Department of Civil Engineering, Jinju National University, 150 Chilam Dong, Jinju, Kyongnam, 660-758 (Korea, Republic of); Park, Sun-Kyu [Department of Civil Engineering, Sungkyunkwan University, 300 Cheoncheon Dong, Jangan Gu, Suwon, Gyeonggi, 440-746 (Korea, Republic of)

2008-06-15

300

Creep and stress rupture of a mechanically alloyed oxide dispersion and precipitation strengthened nickel-base superalloy  

NASA Technical Reports Server (NTRS)

The creep and stress rupture behavior of a mechanically alloyed oxide dispersion strengthened (ODS) and gamma-prime precipitation strengthened nickel-base alloy (alloy MA 6000E) was studied at intermediate and elevated temperatures. At 760 C, MA 6000E exhibits the high creep strength characteristic of nickel-base superalloys and at 1093 C the creep strength is superior to other ODS nickel-base alloys. The stress dependence of the creep rate is very sharp at both test temperatures and the apparent creep activation energy measured around 760 C is high, much larger in magnitude than the self-diffusion energy. Stress rupture in this large grain size material is transgranular and crystallographic cracking is observed. The rupture ductility is dependent on creep strain rate, but usually is low. These and accompanying microstructural results are discussed with respect to other ODS alloys and superalloys and the creep behavior is rationalized by invoking a recently-developed resisting stress model of creep in materials strengthened by second phase particles.

Howson, T. E.; Tien, J. K.; Mervyn, D. A.

1980-01-01

301

From strength to strength: "inner strength" with immature ego states.  

PubMed

The ego-strengthening literature concentrates on the use of hypnotic techniques with the entire or total personality. Ego-state therapy conceptualizes the ego as a system of subpersonalities or ego states that have shifting energies. At any particular time the ego state with the most energy is dominant or executive. Any technique that can be used with an individual patient can also be used with an identified ego state. The "inner-strength" hypnotic technique has been used for ego strengthening and mobilization of inner resources. In this paper the "inner-strength" technique is used with ego states that have been identified as responsible for specific symptoms. We will discuss indications for the appropriate use of this technique in ego-state therapy and the mechanisms of its role in the resolution of symptoms in the cases presented. PMID:8480668

Frederick, C; McNeal, S

1993-04-01

302

Shigella subverts the host recycling compartment to rupture its vacuole.  

PubMed

Shigella enters epithlial cells via internalization into a vacuole. Subsequent vacuolar membrane rupture allows bacterial escape into the cytosol for replication and cell-to-cell spread. Bacterial effectors such as IpgD, a PI(4,5)P2 phosphatase that generates PI(5)P and alters host actin, facilitate this internalization. Here, we identify host proteins involved in Shigella uptake and vacuolar membrane rupture by high-content siRNA screening and subsequently focus on Rab11, a constituent of the recycling compartment. Rab11-positive vesicles are recruited to the invasion site before vacuolar rupture, and Rab11 knockdown dramatically decreases vacuolar membrane rupture. Additionally, Rab11 recruitment is absent and vacuolar rupture is delayed in the ipgD mutant that does not dephosphorylate PI(4,5)P2 into PI(5)P. Ultrastructural analyses of Rab11-positive vesicles further reveal that ipgD mutant-containing vacuoles become confined in actin structures that likely contribute to燿elayed vacular rupture. These findings provide insight into the underlying molecular mechanism of vacuole progression and rupture during Shigella invasion. PMID:25299335

Mellouk, Nora; Weiner, Allon; Aulner, Nathalie; Schmitt, Christine; Elbaum, Michael; Shorte, Spencer L; Danckaert, Anne; Enninga, Jost

2014-10-01

303

Daughter bubble cascades produced by folding of ruptured thin films.  

PubMed

Thin liquid films, such as soap bubbles, have been studied extensively for over a century because they are easily formed and mediate a wide range of transport processes in physics, chemistry and engineering. When a bubble on a liquid-gas or solid-gas interface (referred to herein as an interfacial bubble) ruptures, the general expectation is that the bubble vanishes. More precisely, the ruptured thin film is expected to retract rapidly until it becomes part of the interface, an event that typically occurs within milliseconds. The assumption that ruptured bubbles vanish is central to theories on foam evolution and relevant to health and climate because bubble rupture is a source for aerosol droplets. Here we show that for a large range of fluid parameters, interfacial bubbles can create numerous small bubbles when they rupture, rather than vanishing. We demonstrate, both experimentally and numerically, that the curved film of the ruptured bubble can fold and entrap air as it retracts. The resulting toroidal geometry of the trapped air is unstable, leading to the creation of a ring of smaller bubbles. The higher pressure associated with the higher curvature of the smaller bubbles increases the absorption of gas into the liquid, and increases the efficiency of rupture-induced aerosol dispersal. PMID:20535206

Bird, James C; de Ruiter, Ri雔le; Courbin, Laurent; Stone, Howard A

2010-06-10

304

Factors Controlling Stress Rupture of Fiber-Reinforced Ceramic Composites  

NASA Technical Reports Server (NTRS)

The successful application of fiber-reinforced ceramic matrix composites (CMC) depends strongly on maximizing material rupture life over a wide range of temperatures and applied stresses. The objective of this paper is to examine the various intrinsic and extrinsic factors that control the high-temperature stress rupture of CMC for stresses below and above those required for cracking of the 0 C plies (Regions I and II, respectively). Using creep-rupture results for a variety of ceramic fibers and rupture data for CMC reinforced by these fibers, it is shown that in those cases where the matrix carries little structural load, CMC rupture conditions can be predicted very well from the fiber behavior measured under the appropriate test environment. As such, one can then examine the intrinsic characteristics of the fibers in order to develop design guidelines for selecting fibers and fiber microstructures in order to maximize CMC rupture life. For those cases where the fiber interfacial coatings are unstable in the test environment, CMC lives are generally worse than those predicted by fiber behavior alone. For those cases where the matrix can support structural load, CMC life can even be greater provided matrix creep behavior is properly controlled. Thus the achievement of long CMC rupture life requires understanding and optimizing the behavior of all constituents in the proper manner.

DiCarlo, J. A.; Yun, H. M.

1999-01-01

305

Properties and applications of transversal operators  

E-print Network

This paper presents some properties and applications of "transversal operators". Two transversal operators are presented: a "translation" operator T and a "dilation" operator D. Such operators are used in common analysis systems including Fourier series analysis, Fourier analysis, Gabor analysis, multiresolution analysis (MRA), and wavelet analysis. Like the unitary Fourier transform operator F, the transversal operators T and D are unitary. Demonstrations of the usefulness of these three unitary operators are found in the proofs of results found in some common analytic systems including MRA analysis and wavelet analysis.

Daniel J. Greenhoe

2014-10-20

306

Impact parameter space and transverse distortion  

E-print Network

We investigate the GPDs in impact parameter space using the explicit light front wave functions (LFWFs) for the two-particle Fock state of the electron in QED. The Fourier transform (FT) of the GPDs gives the distribution of quarks in the transverse plane for zero longitudinal momentum transfer ($\\zeta=0$). We study the relationship of the spin flip GPD with the distortion of unpolarized quark distribution in the transverse plane when the target nucleon is transversely polarized and also determine the sign of distortion from the sign of anomalous magnetic moment.

Dahiya, Harleen

2014-01-01

307

Ferroelectric Cathodes in Transverse Magnetic Fields  

SciTech Connect

Experimental investigations of a planar ferroelectric cathode in a transverse magnetic field up to 3 kGs are presented. It is shown that the transverse magnetic field affects differently the operation of ferroelectric plasma cathodes in ''bright'' and ''dark'' modes in vacuum. In the ''bright'' mode, when the surface plasma is formed, the application of the transverse magnetic field leads to an increase of the surface plasma density. In the ''dark'' mode, the magnetic field inhibits the development of electron avalanches along the surface, as it does similarly in other kinds of surface discharges in the pre-breakdown mode.

Alexander Dunaevsky; Yevgeny Raitses; Nathaniel J. Fisch

2002-07-29

308

Transverse Emittance Reduction with Tapered Foil  

SciTech Connect

The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In this paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio. Small transverse emittances are of essential importance for the accelerator facilities generating free electron lasers, especially in hard X-ray region. The idea of reducing transverse emittance with tapered energy-loss foil is recently proposed by B. Carlsten [1], and can be traced back to J.M. Peterson's work in 1980s [2]. Peterson illustrated that a transverse energy gradient can be produced with a tapered energy-loss foil which in turn leads to transverse emittance reduction, and also analyzed the emittance growth from the associated multiple coulomb scattering. However, what Peterson proposed was rather a conceptual than a practical design. In this paper, we build a more complete physical model of the tapered foil based on Ref. [2], including the analysis of the transverse emittance reduction using the concept of eigen emittance and confirming the results by various numerical simulations. The eigen emittance equals to the projected emittance when there is no cross correlation in beam's second order moments matrix [3]. To calculate the eigen emittances, it requires only to know the beam distribution at the foil exit. Thus, the analysis of emittance reduction and the optics design of the subsequent beam line section can be separated. In addition, we can combine the effects of multiple coulomb scattering and transverse energy gradient together in the beam matrix and analyze their net effect. We find that,when applied to an electron linac or electron beam line, the energy spread increase and angular growth due to multiple scattering are not trivial; as a result, the transverse emittance can only be reduced with a limited ratio, e.g. down to about 65% the original value. The contents of this paper are arranged as follows. In Sec. II, we build the physical model of the tapered foil, derive the transverse eigen emittance and discuss the emittance reduction criteria. In Sec. III, we implement numerical simulations to verify the physical model; and in Sec. IV, we present numerical experiments and subsequent beam line to remove the transverse energy gradient to demonstrate the applicability of such method. Conclusions are given in the last section.

Jiao, Yi; Chao, Alex; Cai, Yunhai; /SLAC

2011-12-09

309

TRANSVERSE SPIN AT PHENIX AND FUTURE PLANS.  

SciTech Connect

The PHENIX experiment took data with transversely polarized proton beams in 2001-2002 and measured the transverse single spin asymmetries in inclusive neutral pion and non-identified charge hadrons at midrapidity and {radical} s = 200 GeV. The data near X{sub F} {approx} 0 cover a transverse momentum range from 0.5 to 5.0 GeV/c. The observed asymmetries are consistent with zero with good statistical accuracy. This paper presents the current work in light of earlier measurements at lower energies in this kinematic region and the future plans of the PHENIX detector.

MAKDISI,Y. (FOR THE PHENIX COLLABORATION)

2005-01-28

310

Interaction of dynamic rupture with small-scale heterogeneities  

NASA Astrophysics Data System (ADS)

Broadband ground motion simulations, with frequencies up to 10Hz, are important for engineering purposes, in particular for seismic hazard assessment for critical facilities. One problem in such simulations is the generation of high frequency radiation emitted during the dynamic rupture process. Ad-hoc kinematic rupture characterizations can be tweaked through empirical models to radiate over the desired frequency range, but their physical consistency remains questionable. In contrast, for physically self-consistent dynamic rupture modeling, controlled by friction, material parameters and the adopted physical laws, the mechanism that may lead to appropriate high-frequency radiation require heterogeneity in friction, stress, or fault geometry (or even all three quantities) at unknown but small length scales. Dunham at al. (2011) studied dynamic rupture propagation on rough faults in 2D, and described how fault roughness excites high-frequency radiation. In our study, we focus on the interaction of the dynamic rupture with small-scale heterogeneities on planar faults in 3D. We study effects of the interaction of dynamic rupture with 1) small-scale heterogeneities in the medium (that is, randomized 3D wave speed and density variations), and 2) small-scale heterogeneities in the frictional parameters. Our numerical results show significant variations in rupture velocity or peak slip velocity if small-scale heterogeneities are present. This indicates that the dynamic rupture is sensitive to both types of spatial inhomogeneity. At the same time we observe that the resulting near-source seismic wave fields are not very sensitive to these rupture variations, indicating that wavefront healing effects may "simplify" the complex seismic radiation once the waves propagated several wave-lengths away from the fault.

Galis, Martin; Mai, P. Martin

2014-05-01

311

Cough and spontaneous rupture of a normal spleen.  

PubMed

Rupture of the spleen is a relatively common complication of trauma and many systemic disorders affecting the reticuloendothelial system, including infections and neoplasias. A rare subtype of rupture occurring spontaneously and arising from a normal spleen was recognized as a distinct clinicopathologic entity. The pathogenesis is debated in the absence of external trauma or predisposing disease. It has been reported in association with apparently trivial insults such as vomiting. We report a case of a patient with spontaneous rupture of a normal spleen. Interestingly, it was observed after severe coughing. PMID:16162801

Toubia, Nagib T; Tawk, Maroun M; Potts, Robyn M; Kinasewitz, Gary T

2005-09-01

312

TachoSil for postinfarction ventricular free wall rupture.  

PubMed

Despite a decline in the last three decades, postinfarction ventricular free wall rupture still complicates more than 3% of acute ST-elevation myocardial infarctions and remains a surgical challenge. TachoSil (Nycomed, Zurich, Switzerland) is an equine collagen patch coated with human fibrinogen and human thrombin, which has recently been used for haemostasis in cardiovascular surgery, but its potential usefulness in free wall rupture has not been reported. Initial clinical experience with an on-pump sutureless technique without cardioplegia, using wide TachoSil patching to achieve free wall rupture repair, has been described. PMID:22419793

Pocar, Marco; Passolunghi, Davide; Bregasi, Alda; Donatelli, Francesco

2012-06-01

313

TachoSil for postinfarction ventricular free wall rupture  

PubMed Central

Despite a decline in the last three decades, postinfarction ventricular free wall rupture still complicates more than 3% of acute ST-elevation myocardial infarctions and remains a surgical challenge. TachoSil (Nycomed, Zurich, Switzerland) is an equine collagen patch coated with human fibrinogen and human thrombin, which has recently been used for haemostasis in cardiovascular surgery, but its potential usefulness in free wall rupture has not been reported. Initial clinical experience with an on-pump sutureless technique without cardioplegia, using wide TachoSil patching to achieve free wall rupture repair, has been described. PMID:22419793

Pocar, Marco; Passolunghi, Davide; Bregasi, Alda; Donatelli, Francesco

2012-01-01

314

Ruptured femoral pseudoaneurysm presenting as a lateral abdominal wall hematoma.  

PubMed

Lateral abdominal wall hematomas are rare. We describe a patient with a delayed rupture of a femoral artery pseudoaneurysm, who presented with such a hematoma. In contrast to other types of abdominal wall hematomas, which are often managed conservatively, a ruptured femoral artery pseudoaneurysm frequently requires emergent surgical intervention. Rupture of a pseudoaneurysm can be catastrophic. Due to the rising incidence of femoral artery pseudoaneurysms and shorter hospital stays, it is useful for the emergency physician to be familiar with the diagnosis and management of femoral artery pseudoaneurysms and their potentially life-threatening complications. PMID:16029823

Ma, Marek; Snook, Curtis P

2005-08-01

315

Rupture Propagation beyond Fault Discontinuities: Significance of Thermal Pressurization  

NASA Astrophysics Data System (ADS)

Effect of thermal pressurization (TP) on rupture processes over unconnected fault segments has not been investigated at all. In this study, we show that TP causes various rupture propagation beyond fault discontinuities by 3-D numerical simulations for spontaneous ruptures with TP. We put two vertical strike-slip square faults in a semi-infinite, homogenous, and elastic medium. The second fault (Fault 2) is parallel to the first one (Fault 1). We examine compressional and extensional cases with some values of stepover width. Both faults reach the free surface. The lengths of Faults 1 and 2 are 6 and 3 km, respectively. The numerical algorithm is based on the finite-difference method by Kase and Kuge (2001). Rupture is initiated in a small patch close to a side edge of Fault 1, and then proceeds spontaneously, governed by a slip-weakening law with the Coulomb failure criteria. The friction coefficients and initial stresses are uniform and the same on the two faults. On a fault with TP, we allow effective normal stress to vary with pore pressure change by the formulation of Bizzarri and Cocco (2006). We examine three cases; TP works on neither of the faults ('drain- drain'), on only Fault 2 ('drain-TP'), and on only Fault 1 ('TP-drain'). In the 'drain-drain' case, rupture jumps to Fault 2 near the free surface, and the rupture cannot jump when the stepover width is larger than a certain value. This observation is consistent with Harris and Day (1999) and Kase and Kuge (2001). In the 'drain- TP' case, TP on Fault 2 quickly accelerates propagation of small rupture triggered on Fault 2. In the 'TP- drain' case, the stress drop on Fault 1 is larger and off-fault stress changes drastically. Then, rupture is triggered sometimes near the free surface, as well as rupture triggered at the bottom, and sometimes at a deeper part. Due to these effects of TP, the maximum of stepover width that rupture can jump becomes larger. The effects of TP are observed in both extensional and compressional cases. Therefore, TP has a significant role on whether or not, and where rupture can jump from one fault to another. Moreover, our results imply that the existence and nature of fluid on faults may be diagnosed by comparing rupture jumps between our numerical simulations and real earthquakes.

Urata, Y.; Kuge, K.; Kase, Y.

2008-12-01

316

Minimum Energy Path to Membrane Pore Formation and Rupture  

NASA Astrophysics Data System (ADS)

We combine dynamic self-consistent field theory with the string method to calculate the minimum energy path to membrane pore formation and rupture. In the regime where nucleation can occur on experimentally relevant time scales, the structure of the critical nucleus is between a solvophilic stalk and a locally thinned membrane. Classical nucleation theory fails to capture these molecular details and significantly overestimates the free energy barrier. Our results suggest that thermally nucleated rupture may be an important factor for the low rupture strains observed in lipid membranes.

Ting, Christina L.; Appel, Daniel; Wang, Zhen-Gang

2011-04-01

317

Quadrature Hybrid Coupler Using Photonic Transversal Approach  

Microsoft Academic Search

A novel technique to phase shift signal by 90 degrees over a broad frequency range based on transversal signal processing is proposed and practically demonstrated. The proposed technique is suitable for non coherent optic implementation.

Hossein Emami; Lam Anh Bui; Sana Mansoori; Arnan Mitchell

2008-01-01

318

Quadrature hybrid coupler using photonic transversal approach  

Microsoft Academic Search

A novel technique to phase shift signal by 90 degrees over a broad frequency range based on transversal signal processing is proposed and practically demonstrated. The proposed technique is suitable for non coherent optic implementation.

Hossein Emami; Lam Anh Bui; Sana Mansoori; Arnan Mitchell

2006-01-01

319

Transverse electric plasmons in bilayer graphene  

E-print Network

We predict the existence of transverse electric (TE) plasmons in bilayer graphene. We find that their plasmonic properties are much more pronounced in bilayer than in monolayer graphene, in a sense that they can get more ...

Jablan, Marinko

320

Phenomenology of Transverse Momentum Dependent Parton Densities  

E-print Network

This talk provides a short overview of the phenomenology of transverse momentum depedent distribution and fragmention functions, focussing on the most recent phenomenological developments in the study of their scale evolution and energy depedence.

M. Boglione

2013-09-27

321

Average transverse momentum quantities approaching the lightfront  

E-print Network

In this contribution to Light Cone 2014, three average transverse momentum quantities are discussed: the Sivers shift, the dijet imbalance, and the $p_T$ broadening. The definitions of these quantities involve integrals over all transverse momenta that are overly sensitive to the region of large transverse momenta, which conveys little information about the transverse momentum distributions of quarks and gluons inside hadrons. TMD factorization naturally suggests alternative definitions of such integrated quantities, using Bessel-weighting and rapidity cut-offs, with the conventional definitions as limiting cases. The regularized quantities are given in terms of integrals over the TMDs of interest that are well-defined and moreover have the advantage of being amenable to lattice evaluations.

Boer, Daniel

2014-01-01

322

Development of Transverse Modes Damped DLA Structure  

SciTech Connect

As the dimensions of accelerating structures become smaller and beam intensities higher, the transverse wakefields driven by the beam become quite large with even a slight misalignment of the beam from the geometric axis. These deflection modes can cause inter-bunch beam breakup and intra-bunch head-tail instabilities along the beam path, and thus BBU control becomes a critical issue. All new metal based accelerating structures, like the accelerating structures developed at SLAC or power extractors at CLIC, have designs in which the transverse modes are heavily damped. Similarly, minimizing the transverse wakefield modes (here the HEMmn hybrid modes in Dielectric-Loaded Accelerating (DLA) structures) is also very critical for developing dielectric based high energy accelerators. In this paper, we present the design of a 7.8 GHz transverse mode damped DLA structure currently under construction, along with plans for the experimental program.

Jing, C. [Euclid Techlabs, LLC, 5900 Harper Rd, Solon, OH-44139 (United States); High Energy Physics Division, Argonne National Laboratory, Argonne, IL-60439 (United States); Kanareykin, A.; Schoessow, P. [Euclid Techlabs, LLC, 5900 Harper Rd, Solon, OH-44139 (United States); Gai, W.; Konecny, R.; Power, J. G.; Conde, M. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL-60439 (United States)

2009-01-22

323

Development of Transverse Modes Damped DLA Structure  

NASA Astrophysics Data System (ADS)

As the dimensions of accelerating structures become smaller and beam intensities higher, the transverse wakefields driven by the beam become quite large with even a slight misalignment of the beam from the geometric axis. These deflection modes can cause inter-bunch beam breakup and intra-bunch head-tail instabilities along the beam path, and thus BBU control becomes a critical issue. All new metal based accelerating structures, like the accelerating structures developed at SLAC or power extractors at CLIC, have designs in which the transverse modes are heavily damped. Similarly, minimizing the transverse wakefield modes (here the HEMmn hybrid modes in Dielectric-Loaded Accelerating (DLA) structures) is also very critical for developing dielectric based high energy accelerators. In this paper, we present the design of a 7.8 GHz transverse mode damped DLA structure currently under construction, along with plans for the experimental program.

Jing, C.; Kanareykin, A.; Schoessow, P.; Gai, W.; Konecny, R.; Power, J. G.; Conde, M.

2009-01-01

324

A Controllable Earthquake Rupture Experiment on the Homestake Fault  

NASA Astrophysics Data System (ADS)

Fault-slip is typically simulated in the laboratory at the cm-to-dm scale. Laboratory results are then up-scaled by orders of magnitude to understand faulting and earthquakes processes. We suggest an experimental approach to reactivate faults in-situ at scales ~10-100 m using thermal techniques and fluid injection to modify in situ stresses and the fault strength to the point where the rock fails. Mines where the modified in-situ stresses are sufficient to drive faulting, present an opportunity to conduct such experiments. During our recent field work in the former Homestake gold mine in the northern Black Hills, South Dakota, we found a large fault present on multiple mine levels. The fault is subparallel to the local foliation in the Poorman formation, a Proterozoic metamorphic rock deformed into regional-scale folds with axes plunging ~40 to the SSE. The fault extends at least 1.5 km along strike and dip, with a center ~1.5 km deep. It strikes ~320-340 N, dips ~45-70 NE, and is recognized by a ~0.3-0.5 m thick distinct gouge that contains crushed host rock and black material that appears to be graphite. Although we could not find clear evidence for fault displacement, secondary features suggest that it is a normal fault. The size and distinct structure of this fault make it a promising target for in-situ experimentation of fault strength, hydrological properties, and slip nucleation processes. Most earthquakes are thought to be the result of unstable slip on existing faults, Activation of the Homestake fault in response to the controlled fluid injection and thermally changing background stresses is likely to be localized on a crack-like patch. Slow patch propagation, moderated by the injection rate and the rate of change of the background stresses, may become unstable, leading to the nucleation of a small earthquake (dynamic) rupture. This controlled instability is intimately related to the dependence of the fault strength on the slip process and has been analyzed for the Homestake fault conditions. Scale analyses indicate that this transition occurs for the nucleation patch size ~1 m. This represents a fundamental limitation for laboratory experiments, where the induced dynamic patch could be tractable, and necessitates larger scale field tests ~10-100 m. The ongoing dewatering is expected to affect displacements in the fault vicinity. This poroelastic effect can be used to better characterize the fault. Nucleation, propagation, and arrest of dynamic fault slip is governed by fluid overpressure source, diffusion, and the magnitude of the background loading in relation to the peak and residual strength in the fault zone at the ambient pore pressure level. More information on in-situ stresses than currently available is required to evaluate the fault state. Yet, initial modeling suggests that a suitable place for such an experiment is where the Homestake fault intersects the 4850-ft mine level or at greater depths.

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

2010-12-01

325

Tensile strength of carbyne chains in varied chemical environments and structural lengths  

NASA Astrophysics Data System (ADS)

Carbyne and carbyne-based low-dimensional structures are promising for several applications including ultra-compact circuits and purification devices. Designing any applied carbyne-based structure requires a fundamental understanding of the mechanical strength of carbyne chains with different lengths at different temperatures and operating chemical environment. Here we use molecular dynamics simulations to investigate the strength of carbyne chains with different lengths at different temperatures. A theoretical framework based on statistical mechanics and molecular dynamics results is presented, proving a fast and insightful method for predicting the rupture force and its physical mechanism. The effect of water molecules interaction is also studied on the mechanical properties and it is shown that both the tensile strength and rupture strain are improved by the water interaction. The results of this work can be used for designing and analyzing the robustness and reliability of various carbyne-based materials and applied devices for varies working conditions.

Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J.

2014-09-01

326

Tensile strength of carbyne chains in varied chemical environments and structural lengths.  

PubMed

Carbyne and carbyne-based low-dimensional structures are promising for several applications including ultra-compact circuits and purification devices. Designing any applied carbyne-based structure requires a fundamental understanding of the mechanical strength of carbyne chains with different lengths at different temperatures and operating chemical environment. Here we use molecular dynamics simulations to investigate the strength of carbyne chains with different lengths at different temperatures. A theoretical framework based on statistical mechanics and molecular dynamics results is presented, proving a fast and insightful method for predicting the rupture force and its physical mechanism. The effect of water molecules' interaction is also studied on the mechanical properties and it is shown that both the tensile strength and rupture strain are improved by the water interaction. The results of this work can be used for designing and analyzing the robustness and reliability of various carbyne-based materials and applied devices for varies working conditions. PMID:25148690

Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J

2014-09-19

327

Weyl transverse gravity and the cosmological constant  

SciTech Connect

Scale invariant (transverse) gravitational theories are introduced. They are invariant under pure metric rescalings (i.e. the matter fields are inert under those). This symmetry forbids the presence of a cosmological constant. Those theories are not invariant under the full set of diffeomorphisms, but only with respect to those locally characterized by the fact that their generator is transverse {partial_derivative}{sub {alpha}{xi}}{sup {alpha}=}0.

Alvarez, Enrique; Vidal, Roberto [Instituto de Fisica Teorica UAM/CSIC and Departamento de Fisica Teorica, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)

2010-04-15

328

Acute transverse myelitis complicating breakthrough varicella infection.  

PubMed

We report a 10-year-old girl who presented with acute transverse myelitis after breakthrough varicella infection. The diagnosis was based on the development of motor weakness, paraparesis and bladder dysfunction, spinal magnetic resonance imaging findings and detection of anti-varicella zoster virus IgG antibody in the cerebrospinal fluid. This case report highlights that breakthrough varicella can result in serious complications such as acute transverse myelitis. PMID:24853543

Aslan, Asl; Kurugol, Zafer; Gokben, Sarenur

2014-11-01

329

Transverse electric conductivity of quantum collisional plasmas  

E-print Network

Formulas for calculation of transverse dielectric function and transverse electric conductivity in quantum collisional plasmas under arbitrary degree of degeneracy of the electron gas are received. The Wigner - Vlasov - Boltzmann kinetic equation with collision integral in BGK (Bhatnagar, Gross and Krook) form in coordinate space is used. Various special cases are investigated. The case of fully degenerate quantum plasma was considered separately. Comparison with Lindhard's formula has been realized.

A. V. Latyshev; A. A. Yushkanov

2010-02-04

330

Chiral dynamics and peripheral transverse densities  

SciTech Connect

In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.

Granados, Carlos G. [Uppsala University (Sweden); Weiss, Christian [JLAB, Newport News, VA (United States)

2014-01-01

331

Beam dynamics in transverse deflecting rf structures  

NASA Astrophysics Data System (ADS)

The beam dynamics in transverse deflecting structures, operating in streaking mode, is discussed concentrating on slightly nonrelativistic particle energies. Transverse offsets of the average trajectory, bunch lengthening, and defocusing as well as emittance growth due to nonlinearities of the cavity field are considered. The analysis of the deflecting field reveals the origin of nonlinearities and leads to proposals for their suppression. An optimized cavity design which combines minimal aberrations with a high rf efficiency is proposed.

Floettmann, Klaus; Paramonov, Valentin V.

2014-02-01

332

Isokinetic muscle assessment after treatment of pectoralis major muscle rupture using surgical or non-surgical procedures  

PubMed Central

INTRODUCTION: Rupture of the pectoralis major muscle appears to be increasing in athletes. However, the optimal treatment strategy has not yet been established. OBJECTIVES: To compare the isokinetic shoulder performance after surgical treatment to that after non-surgical treatment for pectoralis major muscle rupture. METHODS: We assessed 33 pectoralis major muscle ruptures (18 treated non-surgically and 15 treated surgically). Horizontal abduction and adduction as well as external and internal rotation at 60 and 120燿egrees/s were tested in both upper limbs. Peak torque, total work, contralateral deficiency, and the peak torque agonist-to-antagonist ratio were measured. RESULTS: Contralateral muscular deficiency did not differ between the surgical and non-surgical treatment modalities. However, the surgical group presented twice the number of athletes with clinically acceptable contralateral deficiency (<20%) for internal rotators compared to the non-surgical group. The peak torque ratio between the external and internal rotator muscles revealed a similar deficit of the external rotation in both groups and on both sides (surgical, 61.60% and 57.80% and non-surgical, 62.06% and 54.06%, for the dominant and non-dominant sides, respectively). The peak torque ratio revealed that the horizontal adduction muscles on the injured side showed similar weakness in both groups (surgical, 86.27%; non-surgical, 98.61%). CONCLUSIONS: This study included the largest single series of athletes reported to date for this type of injury. A comparative analysis of muscular strength and balance showed no differences between the treatment modalities for pectoralis major muscle rupture. However, the number of significant clinical deficiencies was lower in the surgical group than in the non-surgical group, and both treatment modalities require greater attention to the rehabilitation process, especially for the recovery of muscle strength and balance. PMID:21484052

Fleury, Anna Maria; da Silva, Antonio Carlos; de Castro Pochini, Alberto; Ejnisman, Benno; de Lira, Claudio Andre Barbosa; dos Santos Andrade, Marilia

2011-01-01

333

Transverse structure of the QCD string  

SciTech Connect

The characterization of the transverse structure of the QCD string is discussed. We formulate a conjecture as to how the stress-energy tensor of the underlying gauge theory couples to the string degrees of freedom. A consequence of the conjecture is that the energy density and the longitudinal-stress operators measure the distribution of the transverse position of the string, to leading order in the string fluctuations, whereas the transverse-stress operator does not. We interpret recent numerical measurements of the transverse size of the confining string and show that the difference of the energy and longitudinal-stress operators is a particularly natural probe at next-to-leading order. Second, we derive the constraints imposed by open-closed string duality on the transverse structure of the string. We show that a total of three independent ''gravitational'' form factors characterize the transverse profile of the closed string, and obtain the interpretation of recent effective string theory calculations: the square radius of a closed string of length {beta} defined from the slope of its gravitational form factor, is given by (d-1/2{pi}{sigma})log({beta}/4r{sub 0}) in d space dimensions. This is to be compared with the well-known result that the width of the open string at midpoint grows as (d-1/2{pi}{sigma})log(r/r{sub 0}). We also obtain predictions for transition form factors among closed-string states.

Meyer, Harvey B. [Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, 55099 Mainz (Germany)

2010-11-15

334

Age and strength  

Microsoft Academic Search

Using a Smedley hand dynamometer, muscular strength of 552 male industrial manual workers was measured. Results indicate that muscular strength shows an increase to the late twenties and a decline at an increasing rate from that age upward. Explanations of the findings, and the results of previous similar studies are given. 18 references.

M. Bruce Fisher; James E. Birren

1947-01-01

335

46 CFR 154.174 - Transverse contiguous hull structure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Transverse contiguous hull structure. 154.174 Section 154.174 Shipping...Design, Construction and Equipment Hull Structure 154.174 Transverse contiguous hull structure. (a) The transverse contiguous...

2011-10-01

336

46 CFR 154.174 - Transverse contiguous hull structure.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Transverse contiguous hull structure. 154.174 Section 154.174 Shipping...Design, Construction and Equipment Hull Structure 154.174 Transverse contiguous hull structure. (a) The transverse contiguous...

2010-10-01

337

46 CFR 154.174 - Transverse contiguous hull structure.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Transverse contiguous hull structure. 154.174 Section 154.174 Shipping...Design, Construction and Equipment Hull Structure 154.174 Transverse contiguous hull structure. (a) The transverse contiguous...

2013-10-01

338

46 CFR 154.174 - Transverse contiguous hull structure.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Transverse contiguous hull structure. 154.174 Section 154.174 Shipping...Design, Construction and Equipment Hull Structure 154.174 Transverse contiguous hull structure. (a) The transverse contiguous...

2012-10-01

339

Single-knob beam line for transverse emittance partitioning  

NASA Astrophysics Data System (ADS)

Flat beams feature unequal emittances in the horizontal and vertical phase space. Such beams were created successfully in electron machines by applying effective stand-alone solenoid fringe fields in the electron gun. Extension of this method to ion beams was proposed conceptually. The present paper is on the decoupling capabilities of an ion beam emittance transfer line. The proposed beam line provides a single-knob tool to partition the horizontal and vertical rms emittances, while keeping the product of the two emittances constant as well as the transverse rms Twiss parameters (?x,y and ?x,y) in both planes. It is shown that this single knob is the solenoid field strength.

Xiao, C.; Kester, O. K.; Groening, L.; Leibrock, H.; Maier, M.; Rottl鋘der, P.

2013-04-01

340

Rupture process of a multiple main shock sequence: analysis of teleseismic, local and field observations of the Tennant Creek, Australia, earthquakes of January 22, 1988  

USGS Publications Warehouse

On January 22, 1988, three large intraplate earthquakes (with MS 6.3, 6.4 and 6.7) occurred within a 12-hour period near Tennant Creek, Australia. Broadband displacement and velocity records of body waves from teleseismically recorded data are analyzed to determine source mechanisms, depths, and complexity of rupture of each of the three main shocks. Hypocenters of an additional 150 foreshocks and aftershocks constrained by local arrival time data and field observations of surface rupture are used to complement the source characteristics of the main shocks. The interpretation of the combined data sets suggests that the overall rupture process involved unusually complicated stress release. Rupture characteristics suggest that substantial slow slip occurred on each of the three fault interfaces that was not accompanied by major energy release. Variation of focal depth and the strong increase of moment and radiated energy with each main shock imply that lateral variations of strength were more important than vertical gradients of shear stress in controlling the progression of rupture. -from Authors

Choy, G.L.; Bowman, J.R.

1990-01-01

341

Dynamic rupture along bimaterial interfaces in 3D  

NASA Astrophysics Data System (ADS)

We perform numerical simulations of dynamic rupture propagation on a plane in a model consisting of two different elastic half spaces connected via a planar frictional interface governed by regularized Coulomb friction. Therefore, ruptures in this study are purely driven by the presence of a material contrast. Ruptures are nucleated on the fault using a circular symmetric expanding increase of pore-pressure in a limited source region. We show how a wrinkle-like rupture pulse can mature also in the 3D case where we have a mixing of in-plane and anti-plane modes, the instability specific of a bimaterial interface acting only for the in-plane mode. The pulse develops inside a cone-shaped region with its axis aligned with the direction of displacement in the softer material, its tip being at the nucleation region.

Brietzke, G. B.; Cochard, A.; Igel, H.

2007-06-01

342

Multi-Canister overpack necessity of the rupture disk  

SciTech Connect

The Multi-Canister Overpack (MCO) rupture disk precludes the MCO from pressurization above the design limit during transport from the K Basins to the Cold Vacuum Drying (CVD) Facility and prior to connection of the CVD process piping. Removal of the rupture disk from the MCO design would: (a) result in unacceptable dose consequences in the event a thermal runaway accident occurred; (b) increase residual risk; and (c) remove a degree of specificity from the dose calculations. The potential cost savings of removing the rupture disk from the MCO design is offset by the cost of design modifications, changes to hazard analyses and safety analyses, and changes to existing documentation. Retaining the rupture disk mitigates the consequences of MCO overpressurization, and considering the overall economic impacts to the SNF Project, is the most cost effective approach.

SMITH, K.E.

1998-11-03

343

Arterial helium embolism from a ruptured intraaortic balloon.  

PubMed

A 67-year-old man sustained a sudden global neurological deficit immediately following rupture of an intraaortic balloon catheter. Considerable improvement in his neurological function occurred during and after three hyperbaric oxygen treatments. PMID:3196106

Frederiksen, J W; Smith, J; Brown, P; Zinetti, C

1988-12-01

344

Controls on earthquake rupture and triggering mechanisms in subduction zones  

E-print Network

Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison ...

Llenos, Andrea Lesley

2010-01-01

345

Subcutaneous Peroneus Longus Tendon Rupture Associated with OS Peroneum Fracture  

PubMed Central

We report a rare case of subcutaneous peroneus longus tendon rupture associated with os peroneum fracture. Three dimensional computed tomographic scan was useful to understand this disorder. We treated the patient with excision of fractured os peroneum and tenodesis of the proximal stump of the ruptured peroneus longus tendon to the lateral aspect of the calcaneus. Key points In order to understand a rare case of subcutaneous peroneus longus tendon rupture associated with os peroneum fracture, three dimensional computed tomographic scan was useful. The patient was treated with excision of fractured os peroneum and tenodesis of the proximal stump of the ruptured peroneus longus tendon to the lateral aspect of the calcaneus. PMID:24149615

Fujioka, Hiroyuki; Kokubu, Takeshi; Makino, Takeshi; Nagura, Issei; Maeda, Toshihisa; Kurosaka, Masahiro; Okuno, Hiroaki; Yamagiwa, Tokuyoshi; Tanaka, Juichi; Yoshiya, Shinichi

2009-01-01

346

Guide to transverse projections and mass-constraining variables  

NASA Astrophysics Data System (ADS)

This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (mT, meff, mT2, missing p?T, hT, s^min?, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass-bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript 揟 (as in 損?T) in order to remind ourselves what this process of transversification actually means. We note that, far from being simple, transversification can mean quite different things to different people. Those readers who manage to battle through the barrage of transverse notation distinguishing ? from ? or from ?, and 揺arly projection from 搇ate projection, will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or na飗e use of the so-called transverse methods of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the transverse mass they are employing.

Barr, A. J.; Khoo, T. J.; Konar, P.; Kong, K.; Lester, C. G.; Matchev, K. T.; Park, M.

2011-11-01

347

Guide to transverse projections and mass-constraining variables  

E-print Network

This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (mT, mEff, mT2, missing pT, hT, rootsHatMin, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript "T" (as in pT) in order to remind ourselves what this process of transversification actually means. We note that, far from being simple, transversification can mean quite different things to different people. Those readers who manage to battle through the barrage of transverse notation distinguishing mass-preserving projections from velocity preserving projections, and `early projection' from `late projection', will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or naive use of the so-called `transverse' methods of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the `transverse mass' they are employing.

A. J. Barr; T. J. Khoo; P. Konar; K. Kong; C. G. Lester; K. T. Matchev; M. Park

2011-05-15

348

Guide to transverse projections and mass-constraining variables  

SciTech Connect

This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (m{sub T}, m{sub eff}, m{sub T2}, missing p-vector{sub T}, h{sub T}, {radical}(s-circumflex){sub min}, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass-bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript 'T' (as in 'pe{sub T}') in order to remind ourselves what this process of transversification actually means. We note that, far from being simple, transversification can mean quite different things to different people. Those readers who manage to battle through the barrage of transverse notation distinguishing 'T' from 'v' or or from 'o', and 'early projection' from 'late projection', will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or naieve use of the so-called 'transverse methods' of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the 'transverse mass' they are employing.

Barr, A. J. [Department of Physics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Khoo, T. J.; Lester, C. G. [Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Konar, P. [Theoretical Physics Group, Physical Research Laboratory, Ahmedabad, Gujarat - 380 009 (India); Kong, K. [Department of Physics and Astronomy, University of Kansas, Lawrence, KA 66045 (United States); Matchev, K. T.; Park, M. [Department of Physics, University of Florida, Gainesville, Florida 32611 (United States)

2011-11-01

349

Ground States for Mean Field Models with a Transverse Component  

NASA Astrophysics Data System (ADS)

We investigate global logarithmic asymptotics of ground states for a family of quantum mean field models in transverse field. Our approach is based on a stochastic representation and a combination of large deviation and weak KAM techniques. We prove that asymptotic ground states are weak KAM (Fathi in C. R. Acad. Sci., Ser. I Math. 324(9):1043-1046, 1997; Fathi, The Weak KAM Theorem in Lagrangian Dynamics 10th Preliminary Version, 2008; Fathi in Nonlinear Differ. Equ. Appl. 14(1):1-27, 2007) and, in particular, viscosity (Capuzzo-Dolcetta and Lions in Trans. Am. Math. Soc. 318(2):643-683, 1990; Fathi, The Weak KAM Theorem in Lagrangian Dynamics 10th Preliminary Version, 2008, Chap. 7) solutions of certain stationary Hamilton-Jacobi equations. In general such solutions are not unique, and additional refined selection criteria are needed. The spin-1/2 model is worked out in more detail. We discuss phase transitions in the ground state as the strength of the transverse field varies. For a class of mean field interaction potentials this transition is of the first order. For all the models in question, asymptotic ground states with multiple wells necessarily develop shocks. A complete description of asymptotic ground states is derived for ferromagnetic p-body interactions.

Ioffe, Dmitry; Levit, Anna

2013-06-01

350

Lateral approach to laparoscopic repair of left diaphragmatic ruptures  

Microsoft Academic Search

Video-assisted repairs of traumatic diaphragmatic ruptures have been described where thoracoscopy or laparoscopy in the supine\\u000a position were used. This study aims to validate a new lateral laparoscopic approach for left diaphragmatic repairs. Six consecutive\\u000a patients were operated on for left diaphragmatic rupture using a lateral approach (Gagner抯 position). A series of 362 consecutive\\u000a patients presenting with abdominal or thoracic

Pierre Goudet; Nicolas Cheynel; Lo颿 Ferrand; Fr閐閞ique Peschaud; Jean-Philippe Steinmetz; Bernard Letourneau; Jean-Paul Isnardon; Marie-Th閞鑣e Noirot; Laurencia Poli; Marc Freysz; Patrick Cougard

2001-01-01

351

Iliopsoas hematoma due to muscular rupture following defibrillation.  

PubMed

We describe a 62 year old patient who presented with acute anterior ischemia and subsequently developed an iliopsoas hematoma. The patient was treated surgically due to rapid progression and femoral neuropathy, and the iliopsoas muscle rupture was diagnosed intraoperatively. The rupture was related to the external electrical defibrillation the patient had on admission. This was a rare case, and we hope the report would help to raise physicians' awareness regarding this complication and treatment. PMID:24347218

Jahollari, Artan; Cavolli, Raif; Tavlasoglu, Murat; Sallahu, Ferat; Muriqi, Shkelzen

2013-11-01

352

Successful patching of iatrogenic rupture of the fetal membranes.  

PubMed

Rupture of the fetal membranes is a common, but potentially serious complication of invasive fetal procedures. Quintero described a technique to seal the fetal membrane defect by means of a bloodpatch, usually called 'amniopatch' in this application. The successful use in two consecutive patients with ruptured membranes after a fetoscopic intervention at respectively 17 and 22 weeks' gestational age is described, together with a literature review of published experience. PMID:15028428

Lewi, L; Van Schoubroeck, D; Van Ranst, M; Bries, G; Emonds, M-P; Arabin, B; Welch, R; Deprest, J

2004-04-01

353

[Massive hemoperitoneum from rupture of an intra-peritoneal varix].  

PubMed

Rupture of an intra-abdominal varix in a patient with portal hypertension is a rare but severe cause of massive hemoperitoneum. The authors report the case of a patient with alcoholic cirrhosis that presented to the emergency department with hypovolemic shock. Imaging showed massive hemoperitoneum, severe portal hypertension and suggested the diagnosis of spontaneous rupture of an intra-abdominal varix, confirmed at laparotomy. PMID:12469017

L閍ut, F; Frampas, E; Mathon, G; Leborgne, J; Dupas, B

2002-11-01

354

Macrophage Activation in Atherosclerosis: Pathogenesis and Pharmacology of Plaque Rupture  

Microsoft Academic Search

Atherosclerosis is still an important disease. It accounts for 39% of deaths in the U.K. and 12 million U.S citizens have atherosclerosis-associated disease. Atherosclerosis may exert clinical effects by slow narrowing, producing stable angina or dramatic rupture, producing acute coronary syndromes such as unstable angina or myocardial infarction and death. Macrophages are abundant in ruptured atherosclerotic plaques. Macrophages are innate

J. J. Boyle

2005-01-01

355

A support-operator method for 3-D rupture dynamics  

NASA Astrophysics Data System (ADS)

We present a numerical method to simulate spontaneous shear crack propagation within a heterogeneous, 3-D, viscoelastic medium. Wave motions are computed on a logically rectangular hexahedral mesh, using the generalized finite-difference method of Support Operators (SOM). This approach enables modelling of non-planar surfaces and non-planar fault ruptures. Our implementation, the Support Operator Rupture Dynamics (SORD) code, is highly scalable, enabling large-scale, multiprocessors calculations. The fault surface is modelled by coupled double nodes, where rupture occurs as dictated by the local stress conditions and a frictional failure law. The method successfully performs test problems developed for the Southern California Earthquake Center (SCEC)/U.S. Geological Survey (USGS) dynamic earthquake rupture code validation exercise, showing good agreement with semi-analytical boundary integral method results. We undertake further dynamic rupture tests to quantify numerical errors introduced by shear deformations to the hexahedral mesh. We generate a family of meshes distorted by simple shearing, in the along-strike direction, up to a maximum of 73. For SCEC/USGS validation problem number 3, grid-induced errors increase with mesh shear angle, with the logarithm of error approximately proportional to angle over the range tested. At 73, rms misfits are about 10 per cent for peak slip rate, and 0.5 per cent for both rupture time and total slip, indicating that the method (which, up to now, we have applied mainly to near-vertical strike-slip faulting) is also capable of handling geometries appropriate to low-angle surface-rupturing thrust earthquakes. Additionally, we demonstrate non-planar rupture effects, by modifying the test geometry to include, respectively, cylindrical curvature and sharp kinks.

Ely, Geoffrey P.; Day, Steven M.; Minster, Jean-Bernard

2009-06-01

356

A support-operator method for 3-D rupture dynamics  

Microsoft Academic Search

We present a numerical method to simulate spontaneous shear crack propagation within a heterogeneous, 3-D, viscoelastic medium. Wave motions are computed on a logically rectangular hexahedral mesh, using the generalized finite-difference method of Support Operators (SOM). This approach enables modelling of non-planar surfaces and non-planar fault ruptures. Our implementation, the Support Operator Rupture Dynamics (SORD) code, is highly scalable, enabling

Geoffrey P. Ely; Steven M. Day; Jean-Bernard Minster

2009-01-01

357

Anisotropy of high temperature strength in precipitation-hardened nickel-base superalloy single crystals  

NASA Technical Reports Server (NTRS)

The anisotropy of high temperature strength of nickel-base superalloy, Alloy 454, in service for advanced jet engine turbine blades and vanes, was investigated. Crystallographic orientation dependence of tensile yield strength, creep and creep rupture strength was found to be marked at about 760C. In comparison with other single crystal data, a larger allowance in high strength off-axial orientation from the 001 axis, and relatively poor strength at near the -111 axis were noted. From transmission electron microscopy the anisotropic characteristics of this alloy were explained in terms of available slip systems and stacking geometries of gamma-prime precipitate cuboids which are well hardened by a large tantalum content. 100 cube slip was considered to be primarily responsible for the poor strength of the -111 axis orientation replacing the conventional 111 plane slip systems.

Nakagawa, Y. G.; Terashima, H.; Yoshizawa, H.; Ohta, Y.; Murakami, K.

1986-01-01

358

Mechanical behavior of high strength ceramic fibers at high temperatures  

NASA Technical Reports Server (NTRS)

The mechanical behavior of commercially available and developmental ceramic fibers, both oxide and nonoxide, has been experimentally studied at expected use temperatures. In addition, these properties have been compared to results from the literature. Tensile strengths were measured for three SiC-based and three oxide ceramic fibers for temperatures from 25 C to 1400 C. The SiC-based fibers were stronger but less stiff than the oxide fibers at room temperature and retained more of both strength and stiffness to high temperatures. Extensive creep and creep-rupture experiments have been performed on those fibers from this group which had the best strengths above 1200 C in both single filament tests and tests of fiber bundles. The creep rates for the oxides are on the order of two orders of magnitude faster than the polymer derived nonoxide fibers. The most creep resistant filaments available are single crystal c-axis sapphire filaments. Large diameter CVD fabricated SiC fibers are the most creep and rupture resistant nonoxide polycrystalline fibers tested to date.

Tressler, R. E.; Pysher, D. J.

1991-01-01

359

Relationship between High-frequency Radiation and Asperity Ruptures, Revealed by Hybrid Back-projection with a Non-planar Fault Model.  

PubMed

High-frequency seismic waves are generated by abrupt changes of rupture velocity and slip-rate during an earthquake. Therefore, analysis of high-frequency waves is crucial to understanding the dynamic rupture process. Here, we developed a hybrid back-projection method that considers variations in focal mechanisms by introducing a non-planar fault model that reflects the subducting slab geometry. We applied it to teleseismic P-waveforms of the Mw 8.8 2010 Chile earthquake to estimate the spatiotemporal distribution of high-frequency (0.5-2.0?Hz) radiation. By comparing the result with the coseismic slip distribution obtained by waveform inversion, we found that strong high-frequency radiation can precede and may trigger a large asperity rupture. Moreover, in between the large slip events, high-frequency radiation of intermediate strength was concentrated along the rupture front. This distribution suggests that by bridging the two large slips, this intermediate-strength high-frequency radiation might play a key role in the interaction of the large slip events. PMID:25406638

Okuwaki, Ryo; Yagi, Yuji; Hirano, Shiro

2014-01-01

360

Relationship between High-frequency Radiation and Asperity Ruptures, Revealed by Hybrid Back-projection with a Non-planar Fault Model  

PubMed Central

High-frequency seismic waves are generated by abrupt changes of rupture velocity and slip-rate during an earthquake. Therefore, analysis of high-frequency waves is crucial to understanding the dynamic rupture process. Here, we developed a hybrid back-projection method that considers variations in focal mechanisms by introducing a non-planar fault model that reflects the subducting slab geometry. We applied it to teleseismic P-waveforms of the Mw 8.8 2010 Chile earthquake to estimate the spatiotemporal distribution of high-frequency (0.52.0?Hz) radiation. By comparing the result with the coseismic slip distribution obtained by waveform inversion, we found that strong high-frequency radiation can precede and may trigger a large asperity rupture. Moreover, in between the large slip events, high-frequency radiation of intermediate strength was concentrated along the rupture front. This distribution suggests that by bridging the two large slips, this intermediate-strength high-frequency radiation might play a key role in the interaction of the large slip events. PMID:25406638

Okuwaki, Ryo; Yagi, Yuji; Hirano, Shiro

2014-01-01

361

Short term creep rupture predictions for tantalum alloy T-111  

NASA Astrophysics Data System (ADS)

A knowledge of the short term creep rupture behavior of Tantalum alloy T-111 is necessary to predict device integrity in the heat source section of Radioisotope Thermoelectric Generators (RTGs) at the end of service life, in the event of a fuel fire. High pressures exist in RTGs near the end of service life, these are caused by gas generation resulting from radioactive decay of the nuclear fuel. The internal pressure exerts a significant hoop stress on the T-111 alloy structural containment member. This paper analyses the short term creep behavior (rupture times up to 𩛵03 hrs.) of cold worked (CW) T-111 alloy, using the existing data of Stephenson (1967). Corellations for the time to rupture, time to 1% strain and minimum creep rate have been obtained from this data using multivariable linear regression analysis. These results are compared to other short term rupture data for T-111 alloy. Finally, at the stress/temperature levels relevant to the RTG fuel fire scenario near the end of service life, the rupture time correlation for T-111 alloy predicts a rupture time of approximately 100 hrs.

Stephens, John J.

1991-01-01

362

Dynamic rupture modeling with laboratory-derived constitutive relations  

USGS Publications Warehouse

A laboratory-derived state variable friction constitutive relation is used in the numerical simulation of the dynamic growth of an in-plane or mode II shear crack. According to this formulation, originally presented by J.H. Dieterich, frictional resistance varies with the logarithm of the slip rate and with the logarithm of the frictional state variable as identified by A.L. Ruina. Under conditions of steady sliding, the state variable is proportional to (slip rate)-1. Following suddenly introduced increases in slip rate, the rate and state dependencies combine to produce behavior which resembles slip weakening. When rupture nucleation is artificially forced at fixed rupture velocity, rupture models calculated with the state variable friction in a uniformly distributed initial stress field closely resemble earlier rupture models calculated with a slip weakening fault constitutive relation. Model calculations suggest that dynamic rupture following a state variable friction relation is similar to that following a simpler fault slip weakening law. However, when modeling the full cycle of fault motions, rate-dependent frictional responses included in the state variable formulation are important at low slip rates associated with rupture nucleation. -from Author

Okubo, P.G.

1989-01-01

363

Rupture of a Biomembrane under Dynamic Surface Tension  

E-print Network

How long a fluid membrane vesicle stressed with a steady ramp of micropipette last before rupture? Or conversely, how high the surface tension should be to rupture a membrane? To answer these challenging questions we have developed a theoretical framework that allows description and reproduction of Dynamic Tension Spectroscopy (DTS) observations. The kinetics of the membrane rupture under ramps of surface tension is described as a combination of initial pore formation followed by Brownian process of the pore radius crossing the time-dependent energy barrier. We present the formalism and derive (formal) analytical expression of the survival probability describing the fate of the membrane under DTS conditions. Using numerical simulations for the membrane prepared in an initial state with a given distribution of times for pore nucleation, we have studied the membrane lifetime (or inverse of rupture rate) and distribution of membrane surface tension at rupture as a function of membrane characteristics like pore nucleation rate, the energy barrier to failure and tension loading rate. It is found that simulations reproduce main features of the experimental data, particularly, the pore nucleation and pore size diffusion controlled limits of membrane rupture dynamics. This approach can also be applied to processes of permeation and pore opening in membranes (electroporation, membrane disruption by antimicrobial peptides, vesicle fusion).

D. J. Bicout; E. I. Kats

2011-12-19

364

The temporal distribution of seismic radiation during deep earthquake rupture  

USGS Publications Warehouse

The time history of energy release during earthquakes illuminates the process of failure, which remains enigmatic for events deeper than about 100 kilometers. Stacks of teleseismic records from regional arrays for 122 intermediate (depths of 100 to 350 kilometers) and deep (depths of 350 to 700 kilometers) earthquakes show that the temporal pattern of short-period seismic radiation has a systematic variation with depth. On average, for intermediate depth events more radiation is released toward the beginning of the rupture than near the end, whereas for deep events radiation is released symmetrically over the duration of the event, with an abrupt beginning and end of rupture. These findings suggest a variation in the style of rupture related to decreasing fault heterogeneity with depth.The time history of energy release during earthquakes illuminates the process of failure, which remains enigmatic for events deeper than about 100 kilometers. Stacks of teleseismic records from regional arrays for 122 intermediate (depths of 100 to 350 kilometers) and deep (depths of 350 to 700 kilometers) earthquakes show that the temporal pattern of short-period seismic radiation has a systematic variation with depth. On average, for intermediate depth events more radiation is released toward the beginning of the rupture than near the end, whereas for deep events radiation is released symmetrically over the duration of the event, with an abrupt beginning and end of rupture. These findings suggest a variation in the style of rupture related to decreasing fault heterogeneity with depth.

Houston, H.; Vidale, J.E.

1994-01-01

365

Rupture of a biomembrane under dynamic surface tension  

NASA Astrophysics Data System (ADS)

How long will a fluid membrane vesicle stressed with a steady ramp of micropipette last before rupture? Or conversely, how high should the surface tension be to rupture such a membrane? To answer these challenging questions we developed a theoretical framework that allows for the description and reproduction of dynamic tension spectroscopy (DTS) observations. The kinetics of the membrane rupture under ramps of surface tension is described as a succession of an initial pore formation followed by the Brownian process of the pore radius crossing the time-dependent energy barrier. We present the formalism and a derive (formal) analytical expression of the survival probability describing the fate of the membrane under DTS conditions. Using numerical simulations for the membrane prepared in an initial state with a given distribution of times for pore nucleation, we study the membrane lifetime (or inverse of rupture rate) and distribution of membrane surface tension at rupture as a function of membrane characteristics like pore nucleation rate, the energy barrier to failure, and tension loading rate. It is found that simulations reproduce the main features of DTS experiments, particularly the pore nucleation and pore-size diffusion-controlled limits of membrane rupture dynamics. This approach can be adapted and applied to processes of permeation and pore opening in membranes (electroporation, membrane disruption by antimicrobial peptides, vesicle fusion).

Bicout, D. J.; Kats, E.

2012-03-01

366

Compensatory muscle activation caused by tendon lengthening post-Achilles tendon rupture.  

PubMed

PURPOSE: The purpose of this study was to establish a relationship between the lengthening of the Achilles tendon post-rupture and surgical repair to muscle activation patterns during walking in order to serve as a reference for post-surgical assessment. METHOD: The Achilles tendon lengths were collected from 4 patients with an Achilles tendon rupture 6 and 12爉onths post-surgery along with 5 healthy controls via ultrasound. EMG was collected from the triceps surae muscles and tibialis anterior during overground walking. RESULTS: Achilles lengths at 6 and 12爉onths post-surgery were significantly longer (p<0.05) on the involved side compared to the uninvolved side, but there were no side-to-side differences in the healthy controls. The integrated EMG (iEMG) of the involved side was significantly higher than the uninvolved side in the lateral gastrocnemius at 6爉onths and for the medial gastrocnemius at 12爉onths in the patients with Achilles tendon rupture; no side-to-side difference was found in the healthy controls. The triceps surae muscles' activations were fair to moderately correlated to the Achilles lengths (0.38<爎<0.52). CONCLUSIONS: The increased Achilles tendon length and iEMG from the triceps surae muscles indicate that loss of function is primarily caused by anatomical changes in the tendon and the appearance of muscle weakness is due to a lack of force transmission capability. This study indicates that when aiming for full return of function and strength, an important treatment goal appears to be to minimize tendon elongation. LEVEL OF EVIDENCE: Prognostic prospective case series, Level IV. PMID:23609529

Suydam, Stephen M; Buchanan, Thomas S; Manal, Kurt; Silbernagel, Karin Gravare

2013-04-23

367

Compensatory muscle activation caused by tendon lengthening post Achilles tendon rupture  

PubMed Central

Purpose The purpose of this study was to establish a relationship between the lengthening of the Achilles tendon post rupture and surgical repair to muscle activation patterns during walking in order to serve as a reference for post-surgical assessment. Method The Achilles tendon lengths were collected from 4 patients with an Achilles tendon rupture 6 and 12 month post-surgery along with 5 healthy controls via ultrasound. EMG was collected from the triceps surae muscles and tibialis anterior during over-ground walking. Results Achilles lengths at 6 and 12 months post-surgery were significantly longer (p < 0.05) on the involved side compared to the uninvolved side but there were no side to side differences in the healthy controls. The integrated EMG (iEMG) of the involved side was significantly higher than the uninvolved side in the lateral gastrocnemius at 6 months and for the medial gastrocnemius at 12 months in the patients with Achilles tendon rupture; no side to side difference was found in the healthy controls. The triceps surae muscles activations were fair to moderately correlated to the Achilles lengths (0.38 < r < 0.52). Conclusions The increased Achilles tendon length and iEMG from the triceps surae muscles indicate that loss of function is primarily caused by anatomical changes in the tendon and the appearance of muscle weakness is due to a lack of force transmission capability. This study indicates that when aiming for full return of function and strength an important treatment goal appears to be to minimize tendon elongation. Level of evidence Prognostic prospective case series. Level IV. PMID:23609529

Suydam, Stephen M.; Buchanan, Thomas S.; Manal, Kurt; Silbernagel, Karin Gravare

2013-01-01

368

The dynamic rupture and near source ground motion characteristics of thrust, normal and vertical strike slip faults under different tectonic loading regimes  

NASA Astrophysics Data System (ADS)

Distributions of initial stress prior to earthquake rupture are usually arbitrarily assigned in dynamic rupture simulations, hence rendering such calculations questionable for the purpose of adequate ground motion predictions. In this study, we combine stochastic initial stress fields with a realistic fault-loading environment for realistic seismic-hazard relevant near-field ground-motion calculations. The tectonic loading regime (compressional or extensional) and the gravitational loading determine the absolute value of fault frictional resistance if, as usually assumed, friction is governed by the Coulomb friction criterion. These loading characteristics lead to well marked differences in absolute values of initial stress and frictional strength between thrust, normal and vertical strike slip faults. For example, considering that the fault system is initially under confining pressure equivalent to the gravitational load, the accumulated shear stress on the fault due to tectonic loading results in an increased frictional strength in a compressional (thrust faulting) environment due to the increase of the normal stress. On the other hand, the loading in an extensional (normal faulting) regime results in a shear strength reduction due to decreased of normal stress. Additionally, due to the nature of the gravitational loading, the normal stress is depth-dependent which return in depth-dependent frictional strength. This results in a weak near-surface zone unable to maintain large shear stress. Our simulations suggest that rupture at this weak shallow zone should operate in a distinctive manner from the rest of the fault in order to obtain physically plausible rupture models. Then we assume that this shallow zone obeys strength hardening during frictional sliding. Combining these loading environments and frictional properties with realistic heterogeneous stress distributions (characterized by either a fractal field or a von Karman auto-correlation function), we examine rupture complexity and ground motion characteristics for the three classes of faulting (thrust, normal and strike slip) for buried and surface-rupturing earthquakes. Our simulations are tailored to assemble a set of 90 M 6.5 scenario earthquakes (30 for each faulting style), where we compare our simulated ground-motions with empirical predictions and appropriate recent near-field observations.

Dalguer Gudiel, L. A.; Mai, P. M.

2009-12-01

369

Relation of Engine Turbine-blade Life to Stress-rupture Properties of the Alloys, Stellite 21, Hastelloy B, Cast S-816, Forged S-816, X-40, Nimonic 80, Refractaloy 26, N-155, and Inconel X  

NASA Technical Reports Server (NTRS)

An investigation was conducted to relate the engine performance of the heat-resistant alloys, Stellite 21, Hastelloy B, cast S-816, forged S-816, X-40, Nimonic 80, Refractory 26, N-155, and Iconel X to their stress-rupture properties. The engine test consisted of the repetition of a 20-minute cycle, 15 minutes at rated speed and approximately 5 minutes at idle. The results of the investigation indicated a direct correlation between stress-rupture life and blade life for the relatively low-strength alloys. The stress-rupture life and blade life for the relatively high-strength alloys did not correlate because of the effects of the vibratory stresses and the corrosive-gas atmosphere.

Garrett, F B; Yaker, C

1951-01-01

370

Fast domain-wall propagation in uniaxial nanowires with transverse fields  

NASA Astrophysics Data System (ADS)

Under a magnetic field along its axis, domain-wall motion in a uniaxial nanowire is much slower than in the fully anisotropic case, typically by several orders of magnitude (the square of the dimensionless Gilbert damping parameter). However, with the addition of a magnetic field transverse to the wire, this behavior is dramatically reversed; up to a critical field strength, analogous to the Walker breakdown field, domain walls in a uniaxial wire propagate faster than in a fully anisotropic wire (without a transverse field). Beyond this critical field strength, precessional motion sets in, and the mean velocity decreases. Our results are based on leading-order analytic calculations of the velocity and critical field as well as numerical solutions of the Landau-Lifshitz-Gilbert equation.

Goussev, Arseni; Lund, Ross G.; Robbins, J. M.; Slastikov, Valeriy; Sonnenberg, Charles

2013-07-01

371

In-reactor creep rupture of 20% cold-worked AISI 316 stainless steel  

Microsoft Academic Search

Results of an experiment designed to measure in-reactor stress-to-rupture properties of 20% cold-worked AISI 316 stainless steel are reported. The in-reactor rupture data are compared with postirradiation and unirradiated test results. In-reactor rupture lives were found to exceed rupture predictions of postirradiation tests. This longer in-reactor rupture life is attributed to dynamic point defect generation which is absent during postirradiation

A. J. Lovell; B. A. Chin; E. R. Gilbert

1981-01-01

372

Predicting Tensile Strengths of Boron/Aluminum Composites  

NASA Technical Reports Server (NTRS)

To develop predictive theory to account for time/temperature effect of B/A1 composites, series of deformation and fracture studies was performed on commercial boron fibers over wide ranges of stress, stress application time, and temperature. By combining these single fiber results with fracture theory for metal matrix composites, design formulas were derived that describe B/A1 composite tensile and stress rupture strengths as function of time and temperature. Using derived formulas, calculated and experimental results agree to within 3 percent.

Decarlo, J. A.

1982-01-01

373

An oxide dispersion strengthened Ni-W-Al alloy with superior high temperature strength  

NASA Technical Reports Server (NTRS)

An experimental oxide dispersion strengthened (ODS) alloy, WAZ-D, derived from the WAZ-20 composition was produced by the mechanical alloying process. Cast WAZ-20 is strengthened by both a high refractory metal content, and 70 volume percent of gamma prime. The ODS alloy WAZ-D was responsive to variables of alloy content, of attritor processing, of consolidation by extrusion, and of heat treatment. The best material produced had large highly elongated grains. It exhibited tensile strengths generally superior to a comparable cast alloy. The ODS alloy exhibited high temperature stress rupture life considerably superior to any known cast superalloy. Tensile and rupture ductility were low, as was intermediate temperature rupture life. Very low creep rates were noted and some specimens failed with essentially no third stage creep. Also the benefit derived from the oxide dispersion, far out-weighed that from the elongated microstructure alone.

Glasgow, T. K.

1976-01-01

374

STS-93 SSME Nozzle Tube Rupture Investigation  

NASA Technical Reports Server (NTRS)

STS-93 was launched on July 23, 1999. There was an anomaly at the end of the launch in that the main engines shut down 0.16 second early because sensors detected a low level of oxidizer in the LOX tank (actually the duct from the tank to the vehicle). This resulted in a cutoff velocity for the vehicle that was 16 ft/sec low. It should have been 25872 ft/sec. The OMS engines were subsequently used to achieve the proper orbit. An investigation was immediately initiated into the cause of this LOX tank low level cutoff. It was noticed during the launch that the turbine temperatures for Main Engine 3 (E2019) were approximately 100 F higher than the preflight prediction. Linear Engine Model matching of the data indicated that a nozzle leak best fit the data. Post launch review of the data showed, that at approximately five seconds into the start, numerous parameters indicated small anomalous shifts. These shifts were all consistent with a rupture of nozzle tubes. Post launch review of the films showed that just after Space Shuttle Main Engine (SSME) ignition and just prior to liftoff a streak is seen in the exhaust plume of E2019. Just after liftoff the streak can be seen emanating from the nozzle wall. This photo confirmed that a leak was coming from the nozzle tubes. Based on the photo, the axial location of the leak was estimated to be 28 in. from the aft end of the nozzle and in line with nozzle coolant feed line #1. The streak continued to be visible during the launch.

Romine, W. Dennis

1999-01-01

375

Nucleon Spin Structure: Longitudinal and Transverse  

SciTech Connect

Inclusive Deep-Inelastic Scattering (DIS) experiments have provided us with the most extensive information on the unpolarized and longitudinal polarized parton (quark and gluon) distributions in the nucleon. It has becoming clear that transverse spin and transverse momentum dependent distributions (TMDs) study are crucial for a more complete understanding of the nucleon structure and the dynamics of the strong interaction. The transverse spin structure and the TMDs are the subject of increasingly intense theoretical and experimental study recently. With a high luminosity electron beam facility, JLab has played a major role in the worldwide effort to study both the longitudinal and transverse spin structure. Highlights of recent results will be presented. With 12-GeV energy upgrade, JLab will provide the most precise measurements in the valence quark region to close a chapter in longitudinal spin study. JLab will also perform a multi-dimensional mapping of the transverse spin structure and TMDs in the valence quark region through Semi-Inclusive DIS (SIDIS) experiments, providing a 3-d partonic picture of the nucleon in momentum space and extracting the u and d quark tensor charges of the nucleon. The precision mapping of TMDs will also allow a detailed study of the quark orbital motion and its dynamics.

Jian-Ping Chen

2011-02-01

376

Strange hadron production at low transverse momenta  

NASA Astrophysics Data System (ADS)

Some of the latest results of the PHOBOS experiment from the \\sqrt{s_{NN}}= 200\\ GeV Au+Au data are discussed. Those relevant to strangeness production are emphasized. These observations relate to the nature of the matter created when heavy ions collide at the highest achieved energy. The invariant yields of strange and non-strange charged hadrons at very low transverse momentum have been measured, and used to differentiate between different dynamical scenarios. In the intermediate transverse momentum range, the measured ratios of strange and anti-strange kaons approach one, while the antibaryon to baryon ratio is still significantly less, independent of collision centrality and transverse momentum. At high transverse momenta, we find that central and peripheral Au+Au collisions produce similar numbers of charged hadrons per participant nucleon pair, rather than per binary nucleon-nucleon collision. Finally, we describe the upgrades of PHOBOS completed for the 2003 d+Au and p+p run, which extend the transverse momentum range over which particle identification is possible and, at the same time, implement a trigger system selective for high-pT particles.

Veres, G醔or I.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garc韆, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Wo?niak, K.; Wuosmaa, A. H.; Wyslouch, B.; Zhang, J.

2004-01-01

377

Single Molecule Junctions: A Laboratory for Chemistry, Mechanics and Bond Rupture  

SciTech Connect

Simultaneous measurement [1] of junction conductance and sustained force in single molecule junctions bridging metal electrodes provides a powerful tool in the quantitative study of the character of molecule-metal bonds. In this talk I will discuss three topics. First, I will describe chemical trends in link bond strength based on experiments and Density Functional Theory based calculations. Second, I will focus on the specific case of pyridine-linked junctions. Bond rupture from the high conductance junction structure shows a requires a force that exceeds the rupture force of gold point contacts and clearly indicates the role of additional forces, beyond the specific N-Au donor acceptor bond. DFT-D2 calculations with empirical addition of dispersion interactions illustrates the interplay between the donor-acceptor bonding and the non-specific van der Waals interactions between the pyridine rings and Au asperities. Third, I will describe recent efforts to characterize the diversity of junction structures realized in break-junction experiments with suitable models for the potential surfaces that are observed. [1] Venkataraman Group, Columbia University.

Hybertsen M. S.

2013-07-08

378

Crew Strength Training  

NASA Video Gallery

Train to develop your upper and lower body strength in your muscles and bones by performing body-weight squats and push-ups.The Train Like an Astronaut project uses the excitement of exploration to...

379

Apple Strength Issues  

SciTech Connect

Strength of the apple parts has been noticed to decrease, especially those installed by the new induction heating system since the LEP campaign started. Fig. 1 shows the ultimate tensile strength (UTS), yield strength (YS), and elongation of the installed or installation-simulated apples on various systems. One can clearly see the mean values of UTS and YS of the post-LEP parts decreased by about 8 ksi and 6 ksi respectively from those of the pre-LEP parts. The slight increase in elongation seen in Fig.1 can be understood from the weak inverse relationship between the strength and elongation in metals. Fig.2 shows the weak correlation between the YS and elongation of the parts listed in Fig. 1. Strength data listed in Figure 1 were re-plotted as histograms in Figs. 3 and 4. Figs. 3a and 4a show histograms of all UTS and YS data. Figs. 3b and 4b shows histograms of pre-LEP data and Figs. 3c and 4c of post-LEP data. Data on statistical scatter of tensile strengths have been rarely published by material suppliers. Instead, only the minimum 'guaranteed' strength data are typically presented. An example of strength distribution of aluminum 7075-T6 sheet material, listed in Fig. 5, show that its scatter width of both UTS and YS for a single sheet can be about 6 ksi and for multi-lot scatter can be as large as 11 ksi even though the sheets have been produced through well-controlled manufacturing process. By approximating the histograms shown in Figs. 3 and 4 by a Gaussian or similar type of distribution curves, one can plausibly see the strength reductions in the later or more recent apples. The pre-LEP data in Figs. 3b and 4b show wider scatter than the post-LEP data in Figs. 3c and 4c and seem to follow the binomial distribution of strength indicating that the apples might have been made from two different lots of material, either from two different vendors or from two different melts of perhaps slightly different chemical composition by a single vendor. The post-LEP apples seem to have been from a single batch of material. The pre-LEP apples of the weak strength and the post-LEP apples with even weaker strength could have been made of the same batch of material, and the small strength differential might be due to the difference in the induction heating system. If the pre-LEP apples with the lower strength and the post LEP apples are made from the same batch of material, their combined scatter of strength data would be wider and can be understood as a result of the additional processing steps of stress relief and induction heating as discussed.

Syn, C

2009-12-22

380

Creep-rupture behavior of candidate Stirling engine iron supperalloys in high-pressure hydrogen. Volume 2: Hydrogen creep-rupture behavior  

NASA Technical Reports Server (NTRS)

The creep rupture behavior of nine iron base and one cobalt base candidate Stirling engine alloys is evaluated. Rupture life, minimum creep rate, and time to 1% strain data are analyzed. The 3500 h rupture life stress and stress to obtain 1% strain in 3500 h are also estimated.

Bhattacharyya, S.; Peterman, W.; Hales, C.

1984-01-01

381

Time-dependent mechanical properties of polymeric coatings used in rupturable pulsatile release dosage forms.  

PubMed

The mechanical properties of polymer films used in pharmaceutical coatings of pulsatile drug delivery systems were evaluated in the dry and the wet state by a newly developed puncture test, which allowed the time-dependent measurement of the mechanical properties on the same film specimen. Force, puncture strength, energy at break, modulus, and strain were investigated as a function of water exposure time with respect to the type of polymer and the type and concentration of plasticizer and pore former (hydroxypropyl methylcellulose, HPMC). Eudragit RS films were very flexible, had a high strain, and broke upon puncture with only small cracks. In contrast, ethylcellulose films were more brittle with a lower strain and showed complete film rupture. Increased amounts of the hydrophilic pore former, HPMC, resulted in a reduced puncture strength and in an increase in water uptake and weight loss of the films. The puncture strength decreased with increasing plasticizer concentration and was lower with the lipophilic dibutyl sebacate than with the hydrophilic triethyl citrate. PMID:12889780

Bussemer, T; Peppas, N A; Bodmeier, R

2003-07-01

382

Evolution of transverse modes in FELIX macropulses  

SciTech Connect

We present ringdown measurements of both the intracavity beam, using a low reflection beamsplitter, as well as the hole-outcoupled beam of FELIX, the intracavity measurements being taken at various sets of transverse coordinates. Recent measurements show a significant difference in the decay of the signals at different radial positions, suggesting the presence of higher order transverse modes. The formation of transverse modes depends on the properties of the cold cavity and its losses (i.e. resonator parameters, diffraction and outcoupling at the hole, absorption and edge losses on the mirrors, waveguide clipping), as well as on the gain mechanism. Both simulations with the axisymmetric ELIXER code and previous hole-outcoupled measurements indicated a substantial energy content of the 2nd or 4th Gauss-Laguerre (GL) mode for the 20-30 {mu}m regime of FELIX. Moreover, as FELIX has a phase degenerate cavity, the fundamental and higher order transverse modes can interplay to create a reduced outcoupling efficiency at the hole. For example, in contrast to the decay rate of 13% per roundtrip that we would expect for a pure gaussian beam when we include a loss of 6% for the reflection at the intracavity beamsplitter, recent simulations indicate a decay rate as high as 23% of the hole-outcoupled signal. In this case the 2nd order GL mode contains 30% of the total intracavity power. The effect of transverse modes on subpulses in the limit cycle regime is an interesting aspect. As soon as a subpulse is losing contact with the electrons, its transverse pattern will exhibit an on-axis hole after a few roundtrips, according to the simulations. This process could mean that the subpulses are less pronounced in the hole-outcoupled signal of FELIX 1.

Weits, H.H.; Lin, L.; Werkhoven, G.H.C. van [FOM-Institute for Plasma Physics, Nieuwegin (Netherlands)] [and others

1995-12-31

383

Hemodynamic-Morphologic Discriminants for Intracranial Aneurysm Rupture  

PubMed Central

Background and Purpose To identify significant morphologic and hemodynamic parameters that discriminate intracranial aneurysm (IA) rupture status using 3D angiography and computational fluid dynamics (CFD). Methods 119 IAs (38 ruptured, 81 unruptured) were analyzed from 3D angiographic images and CFD. Six morphologic and seven hemodynamic parameters were evaluated for significance with respect to rupture. Receiver-operating characteristic (ROC) analysis identified area under the curve (AUC) and optimal thresholds separating ruptured from unruptured aneurysms for each parameter. Significant parameters were examined by multivariate logistic regression analysis in 3 predictive models梞orphology only, hemodynamics only, and combined梩o identify independent discriminants, and the AUC-ROC of the predicted probability of rupture status was compared among these models. Results Morphologic parameters (Size Ratio [SR], Undulation Index, Ellipticity Index, and Nonsphericity Index) and hemodynamic parameters (Average Wall Shear Stress [WSS], Maximum intra-aneurysmal WSS, Low WSS Area, Average Oscillatory Shear Index [OSI], Number of Vortices, and Relative Resident Time) achieved statistical significance (p<0.01). Multivariate logistic regression analysis demonstrated SR to be the only independently significant factor in the morphology model (AUC=0.83, 95% confidence interval [CI] 0.750.91), whereas WSS and OSI were the only independently significant variables in the hemodynamics model (AUC=0.85, 95% CI 0.780.93). The combined model retained all three variables, SR, WSS, and OSI (AUC=0.89, 95% CI 0.820.96). Conclusion All three models梞orphological (based on SR), hemodynamic (based on WSS and OSI), and combined梔iscriminate IA rupture status with high AUC values. Hemodynamics is as important as morphology in discriminating aneurysm rupture status. PMID:21106956

Xiang, Jianping; Natarajan, Sabareesh K.; Tremmel, Markus; Ma, Ding; Mocco, J; Hopkins, L. Nelson; Siddiqui, Adnan H.; Levy, Elad I.; Meng, Hui

2010-01-01

384

Morphological Parameters Associated with Ruptured Posterior Communicating Aneurysms  

PubMed Central

The rupture risk of unruptured intracranial aneurysms is known to be dependent on the size of the aneurysm. However, the association of morphological characteristics with ruptured aneurysms has not been established in a systematic and location specific manner for the most common aneurysm locations. We evaluated posterior communicating artery (PCoA) aneurysms for morphological parameters associated with aneurysm rupture in that location. CT angiograms were evaluated to generate 3-D models of the aneurysms and surrounding vasculature. Univariate and multivariate analyses were performed to evaluate morphological parameters including aneurysm volume, aspect ratio, size ratio, distance to ICA bifurcation, aneurysm angle, vessel angles, flow angles, and vessel-to-vessel angles. From 20052012, 148 PCoA aneurysms were treated in a single institution. Preoperative CTAs from 63 patients (40 ruptured, 23 unruptured) were available and analyzed. Multivariate logistic regression revealed that smaller volume (p?=?0.011), larger aneurysm neck diameter (0.048), and shorter ICA bifurcation to aneurysm distance (p?=?0.005) were the most strongly associated with aneurysm rupture after adjusting for all other clinical and morphological variables. Multivariate subgroup analysis for patients with visualized PCoA demonstrated that larger neck diameter (p?=?0.018) and shorter ICA bifurcation to aneurysm distance (p?=?0.011) were significantly associated with rupture. Intracerebral hemorrhage was associated with smaller volume, larger maximum height, and smaller aneurysm angle, in addition to lateral projection, male sex, and lack of hypertension. We found that shorter ICA bifurcation to aneurysm distance is significantly associated with PCoA aneurysm rupture. This is a new physically intuitive parameter that can be measured easily and therefore be readily applied in clinical practice to aid in the evaluation of patients with PCoA aneurysms. PMID:24733151

Ho, Allen; Lin, Ning; Charoenvimolphan, Nareerat; Stanley, Mary; Frerichs, Kai U.; Day, Arthur L.; Du, Rose

2014-01-01

385

Comparison of isokinetic strength and H:Q ratio between ACL reconstructed athletes and non-injured athletes  

Microsoft Academic Search

Evaluation of muscle function can be helpful in rehabilitation programmes with knee injuries. The purpose of this study was to compare isokinetic strength and H:Q ratio between ACL reconstructed (injured group) and healthy (control group) athletes. Twelve elite athletes (6 handball, 6 soccer) with a unilateral ACL rupture who had received a hamstring tendon autografts ACL reconstruction (mean duration 21

Ebrahim Khosravi; Gholamali Ghasemi; Vahid Zolaktaf

2010-01-01

386

Evaluation of post-fire strength of concrete flexural members reinforced with glass fiber reinforced polymer (GFRP) bars  

Microsoft Academic Search

Owing to their corrosion resistance and superior strength to weight ratio, there has been, over the past two decades, increased interest in the use of fiber-reinforced polymer (FRP) reinforcing bars in reinforced concrete structural members. The mechanical behavior of FRP reinforcement differs from that of steel reinforcement. For example, FRP reinforcement exhibit a linear stress-strain behavior until the bar ruptures

Devon S. Ellis

2009-01-01

387

Possibilities for reduction of transverse projected emittances by partial removal of transverse to longitudinal beam correlations  

E-print Network

We show that if in the particle beam there are linear correlations between energy of particles and their transverse positions and momenta (linear beam dispersions), then the transverse projected emittances always can be reduced by letting the beam to pass through magnetostatic system with specially chosen nonzero lattice dispersions. The maximum possible reduction of the transverse projected emittances occurs when all beam dispersions are zeroed, and the values of the lattice dispersions required for that are completely defined by the values of the beam dispersions and the beam rms energy spread and are independent from any other second-order central beam moments. Besides that, we prove that, alternatively, one can also use the lattice dispersions to remove linear correlations between longitudinal positions of particles and their transverse coordinates (linear beam tilts), but in this situation solution for the lattice dispersions is nonunique and the reduction of the transverse projected emittances is not gu...

Balandin, V; Golubeva, N

2014-01-01

388

Quadriceps Activation Failure After Anterior Cruciate Ligament Rupture Is Not Mediated by Knee Joint Effusion  

PubMed Central

STUDY DESIGN Descriptive prospective cohort study. OBJECTIVES To investigate the relationships between knee joint effusion, quadriceps activation, and quadriceps strength. These relationships may help clinicians better identify impaired quadriceps activation. BACKGROUND After anterior cruciate ligament (ACL) injury, the involved quadriceps may demonstrate weakness. Experimental data have shown that quadriceps activation and strength may be directly mediated by intracapsular joint pressure created by saline injection. An inverse relationship between quadriceps activation and the amount of saline injected has been reported. This association has not been demonstrated for traumatic effusion. We hypothesized that traumatic joint effusion due to ACL rupture and postinjury quadriceps strength would correlate well with quadriceps activation, allowing clinicians to use effusion and strength measurement as a surrogate for electrophysiological assessment of quadriceps activation. METHODS Prospective data were collected on 188 patients within 100 days of ACL injury (average, 27 days) referred from a single surgeon. A complete clinical evaluation of the knee was performed, including ligamentous assessment and assessment of range of motion and effusion. Quadriceps function was electrophysiologically assessed using maximal volitional isometric contraction and burst superimposition techniques to quantify both strength and activation. RESULTS Effusion grade did not correlate with quadriceps central activation ratio (CAR) (zero effusion: mean SD CAR, 93.5% 5.8%; trace effusion: CAR, 93.8% 9.5%; 1+ effusion: CAR, 94.0% 7.5%; 2+/3+ effusion: CAR, 90.6% 11.1%). These values are lower than normative data from healthy subjects (CAR, 98% 3%). CONCLUSION Joint effusion after ACL injury does not directly mediate quadriceps activation failure seen after injury. Therefore, it should not be used as a clinical substitute for electrophysiological assessment of quadriceps activation. Patients presenting to physical therapy after ACL injury should be treated with high-intensity neuromuscular electrical stimulation to help normalize this activation. PMID:22523081

LYNCH, ANDREW D.; LOGERSTEDT, DAVID S.; AXE, MICHAEL J.; SNYDER-MACKLER, LYNN

2013-01-01

389

Early recovery in post Varicella transverse myelitis.  

PubMed

A 7 years old boy presenting with acute flaccid paralysis after Varicella zoster infection was diagnosed as having acute transverse myelitis on MRI. He recovered fully after treatment with intravenous corticosteroids and acyclovir. The occurrence of this condition during or following Varicella infection is uncommon. There are previously very few reported cases of post-Varicella acute transverse myelitis in which recovery started after 3 months of treatment. In this case complete recovery occurred in 2 weeks of treatment. This report emphasizes the need for Varicella zoster vaccine to prevent not only acute Varicella, but also its rare postinfectious neurologic sequelae. PMID:24906257

Chand, Prem; Ibrahim, Shahnaz; Zaidi, Syed Sohail; Amjad, Nida

2014-05-01

390

Successful pregnancy in a woman with uterine scarring by transverse fundal cesarean section.  

PubMed

There has been only one case to date of pregnancy outcome after fundal transverse cesarean section (FTC). We report a pregnancy established after FTC. The FTC was performed at gestational week (GW) 24 in this patient's first pregnancy, but the uterus was preserved. Magnetic resonance imaging studies performed four times in her second pregnancy consistently showed part of the uterine fundus in which the muscle layer was interrupted. Concern regarding spontaneous uterine rupture in the absence of labor pains prompted us to interrupt her pregnancy at GW 31(+5) , delivering a premature, but otherwise healthy female infant, weighing 1832 g. The infant required transient intratracheal intubation for respiratory distress syndrome (for less than 1 h), but had an otherwise uneventful clinical course. Two cases, including ours, suggest that successful pregnancy outcome is feasible at least in some women with uterine scarring due to FTC. PMID:24754852

Nishida, Ryutaro; Morikawa, Mamoru; Yamada, Takahiro; Takeda, Masamitsu; Akaishi, Rina; Cho, Kazutoshi; Minakami, Hisanori

2014-05-01

391

Generation of microcracks by dynamic shear rupture and its effects on rupture growth and elastic wave radiation  

NASA Astrophysics Data System (ADS)

Laboratory and field observations suggest that dynamically propagating earthquake faults generate a large number of tensile microcracks in their vicinity, which will contribute to the formation of fault zones. Intense interactions are expected to occur between such microcracks and a dynamically propagating fault, which will complicate the fault growth. Near-field seismic waves will also be affected by the generation of microcracks. We numerically study how such tensile microcracks are generated and how dynamic growth of a macroscopic shear rupture and near-field elastic waves are affected by the distribution of generated microcracks. It is essential to consider a large number of microcracks in such studies, so that it is impractical to consider each microcrack individually from the viewpoint of computation time and memory. We overcome this difficulty by representing the microcrack distribution by anisotropic properties of the overall elastic coefficients on the basis of Hudson's (1980) study. Our simulations show that the decrease in the microcrack density is approximated well by a logarithmic function of the distance from the rupture plane. Microcracks on the dilational side of the rupture plane are shown to make larger angles to the rupture plane than on the compressive side. These are consistent with field and laboratory observations. It is also shown that dynamically generated microcracks tend to reduce the rupture-tip shear stress. This implies that the dynamic growth of a shear rupture is more decelerated when microcracks are generated than when the shear rupture is isolated in an isotropic and homogeneous medium. If the dynamic rupture growth is arrested suddenly, an abrupt expansion of the distribution zone of microcracks is shown to occur near the arrested rupture tip. Aftershocks are expected to cluster in this zone because of the shear stress enhancement there and the high density of distributed microcracks, which facilitates aftershock occurrence due to dynamic coalescence of microcracks. Our simulations also show that the component of radiated displacement waves perpendicular to the rupture plane is much more affected by the generation of microcracks than the parallel component.

Yamashita, Teruo

2000-11-01

392

The Mw 6.5 offshore Northern California earthquake of 10 January 2010: Ordinary stress drop on a high-strength fault  

NASA Astrophysics Data System (ADS)

10 January 2010 Mw 6.5 earthquake offshore Northern California is one of the first intraplate earthquakes in oceanic lithosphere to be well captured by a GPS network. It presents an opportunity to evaluate rupture mechanics on a high-strength fault. Static inversion of the coseismic displacements shows that the slip peaks at the same depth as the expected strength envelope, where the differential stresses can be as high as 600 MPa. Laboratory experiments on peridotite predict dramatic dynamic weakening at these conditions. The observed ordinary stress drop, 2-20 MPa, may indicate that the lithosphere is much weaker than strength envelope predicts or that the failure mechanisms seen in the laboratory are not occurring during the rupture. The GPS observations show very little postseismic signal indicating that if a shear zone exists beneath the coseismic rupture, it operates at significantly greater stress levels than the coseismic stress change.

Wei, Meng; McGuire, Jeffrey J.

2014-09-01

393

Distribution of stress drop, stiffness, and fracture energy over earthquake rupture zones  

USGS Publications Warehouse

Using information provided by slip models and the methodology of McGarr and Fletcher (2002), we map static stress drop, stiffness (k = ????/u, where ???? is static stress drop and u is slip), and fracture energy over the slip surface to investigate the earthquake rupture process and energy budget. For the 1994 M6.7 Northridge, 1992 M7.3 Landers, and 1995 M6.9 Kobe earthquakes, the distributions of static stress drop show strong heterogeneity, emphasizing the importance of asperities in the rupture process. Average values of static stress drop are 17, 11, and 4 Mpa for Northridge, Landers, and Kobe, respectively. These values are substantially higher than estimates based on simple crack models, suggesting that the failure process involves the rupture of asperities within the larger fault zone. Stress drop as a function of depth for the Northridge and Landers earthquakes suggests that stress drops are limited by crustal strength. For these two earthquakes, regions of high slip are surrounded by high values of stiffness. Particularly for the Northridge earthquake, the prominent patch of high slip in the central part of the fault is bordered by a ring of high stiffness and is consistent with expectations based on the failure of an asperity loaded at its edge due to exterior slip. Stiffness within an asperity is inversely related to its dimensions. Estimates of fracture energy, based on static stress drop, slip, and rupture speed, were used to investigate the nature of slip weakening at four locations near the hypocenter of the Kobe earthquake for comparison with independent results based on a dynamic model of this earthquake. One subfault updip and to the NE of the hypocenter has a fracture energy of 1.1 MJ/m2 and a slip-weakening distance, Dc, of 0.66 m. Right triangles, whose base and height are Dc and the dynamic stress drop, respectively, approximately overlie the slip-dependent stress given by Ide and Takeo (1997) for the same locations near the hypocenter. The total fracture energy for the Kobe earthquake, 3.7 ?? 1014 J, is about the same as the seismic energy (Ea = 3.2 ?? 1014 J.

Fletcher, J. B.; McGarr, A.

2006-01-01

394

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

USGS Publications Warehouse

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 point is comparable to the overall duration of the rupture; i.e. slip at a given point continues until information is received that the rupture has stopped propagating. Alternative explanations for the discrepancy between the short slip durations used to model waveforms and the long slip durations inferred from dynamic crack models are: (1) the dislocation models are unable to resolve the relatively slow parts of earthquake slip and have seriously underestimated the dislocations for these earthquakes; (2) earthquakes are composed of a sequence of small-dimension (short duration) events that are separated by locked regions (barriers); (3) rupture occurs in a narrow self-healing pulse of slip that travels along the fault surface. Evidence is discussed that suggests that slip durations are indeed short and that the self-healing slip-pulse model is the most appropriate explanation. A qualitative model is presented that produces self-healing slip pulses. The key feature of the model is the assumption that friction on the fault surface is inversely related to the local slip velocity. The model has the following features: high static strength of materials (kilobar range), low static stress drops (in the range of tens of bars), and relatively low frictional stress during slip (less than several hundreds of bars). It is suggested that the reason that the average dislocation scales with fault length is because large-amplitude slip pulses are difficult to stop and hence tend to propagate large distances. This model may explain why seismicity and ambient stress are low along fault segments that have experienced large earthquakes. It also qualitatively explains why the recurrence time for large earthquakes may be irregular. ?? 1990.

Heaton, T.H.

1990-01-01

395

Dynamic strength measurement using magnetically applied pressure shear (MAPS)  

NASA Astrophysics Data System (ADS)

A newly developed experimental technique to measure dynamic material strength at high pressures on magneto-hydrodynamic (MHD) drive pulsed power platforms is demonstrated on aluminum. The application of an external magnetic field normal to the plane of the MHD drive current directly induces a shear stress wave in addition to the usual longitudinal stress wave. Strength is probed by passing this shear wave through the sample material where the transmissible shear stress is limited to the sample strength. The magnitude of the transmitted shear wave is measured via a transverse VISAR system from which the sample strength is determined. Details of the experimental approach will be presented along with results of initial experiments on 99.5% pure aluminum which demonstrate the utility of the technique.

Alexander, C. S.; Asay, J. R.; Haill, T. A.

2011-06-01

396

Earthquake Rupture Complexity Evidence from Field Observations (Invited)  

NASA Astrophysics Data System (ADS)

Field observations provide strong evidence for four intriguing aspects of rupture process complexity for the 4 April 2010 El Mayor - Cucapah - Indiviso earthquake. First, the southern 揻ork of the rupture exhibits two splays just to the northwest of the event epicenter, both with nearly pure right-lateral faulting. Teleseismic source modeling by others indicates normal slip on deep fault surface preceded the shallow strike-slip faulting, and our field observations from the fork area indicate that the earliest phase of strike-slip faulting did not involve a significant normal faulting component. Second, as rupture propagated to the northwest along the Pescadores fault, slip ended abruptly on this fault and transferred across a complex zone to the Borrego fault (although the Pescadores fault continues farther and would have seemed an easier route to follow). This stepover is called the Puerta Accommodation Zone (PAZ) which extends 11 km along-strike within an elevated portion of the Cucapah massif and accommodates a left step (transpressional) that measures less than 2 km across-strike. Though partly obscured by rockfalls in the steep terrain here, only discontinuous faulting of up to one meter reached the ground surface, yet imagery differencing by others indicates several meters of continuous subsurface slip throughout this section. This 11 km region of reduced and discontinuous slip is one of the longest surface rupture jumps ever observed, with lengthy and continuous surface faulting on either side. The SE end of the stepover coincides spatially with the Canon Rojo embayment where the M7.2 1892 surface rupture propagated onto a second fault forming an abrupt corner in its surface trace. Hence, the surface rupture and slip distribution pattern in 2010 appears to have been influenced by stress changes induced by the 1892 event. Thirdly, from the NW end of the transition section, the Borrego fault continues to the NNW with strong east-down slip obliquity. Along this same reach of fault, the Laguna Salada fault was re-activated with minor west side down slip. Along the Paso Inferior accommodation zone, splays trending NNW to N had strong east-down slip, with right-lateral oblique motion. It was along this portion of the rupture that an eyewitness observed the rupture propagating from N to S, instead of in the expected S to N direction. Back-rupture may have resulted from triggered slip having raced ahead of the slower main rupture front, or may indicate a place where contiguous deep rupture ran out in front of shallow slip, or may result from the involvement here of the detachment fault system. Finally, in the northwestern portion of the rupture, from Paso Superior to the northwest of Cerro Centinela, a pattern of NE - SW oriented 揷ross faults and N-S faults broke at the surface, in a manner similar to rupture that occurred in the Elmore Ranch Fault Zone during the Superstition Hills earthquake sequence of 1987. Unlike the Elmore Ranch event, however, there was no known main shock sub-event or any large aftershock that can be readily associated with the extensive cross-faulting that is observed in this case.

Hudnut, K. W.; Fletcher, J. M.; Rockwell, T. K.; Gonzalez-Garcia, J. J.; Teran, O.; Akciz, S. O.

2010-12-01

397

On the strength of ?-sheet crystallites of Bombyx mori silk fibroin.  

PubMed

Silk fibroin, a natural multi-domain protein, has attracted great attention due to its superior mechanical properties such as ultra-high strength and stretchability, biocompatibility, as well as its versatile biodegradability and processability. It is mainly composed of ?-sheet crystallites and amorphous domains. Although its strength is well known to be controlled by the dissociation of protein chains from ?-sheet crystallites, the way that water as the solvent affects its strength and the reason that its theoretically predicted strength is several times higher than experimental measurement remain unclear. We perform all-atom molecular dynamics simulations on a ?-sheet crystallite of Bombyx mori silk. We find that water solvent reduces the number and strength of hydrogen bonds between ?-chains, and thus greatly weakens the strength of silk fibroin. By dissociating protein chains at different locations from the crystallite, we also find that the pulling strength for the interior chains is several times higher than that for the surface/corner chains, with the former being consistent with the theoretically predicted value, while the latter on par with the experimental value. It is shown that the weakest rupture strength controls the failure strength of silk fibre. Hence, this work sheds light on the role of water in the strength of silk fibroin and also provides clues on the origin of the strength difference between theory and experiment. PMID:24789564

Cheng, Yuan; Koh, Leng-Duei; Li, Dechang; Ji, Baohua; Han, Ming-Yong; Zhang, Yong-Wei

2014-07-01

398

Composite Overwrapped Pressure Vessels (COPV) Stress Rupture Test  

NASA Technical Reports Server (NTRS)

One of the major concerns for the aging Space Shuttle fleet is the stress rupture life of composite overwrapped pressure vessels (COPVs). Stress rupture life of a COPV has been defined as the minimum time during which the composite maintains structural integrity considering the combined effects of stress levels and time. To assist in the evaluation of the aging COPVs in the Orbiter fleet an analytical reliability model was developed. The actual data used to construct this model was from testing of COPVs constructed of similar, but not exactly same materials and pressure cycles as used on Orbiter vessels. Since no actual Orbiter COPV stress rupture data exists the Space Shuttle Program decided to run a stress rupture test to compare to model predictions. Due to availability of spares, the testing was unfortunately limited to one 40" vessel. The stress rupture test was performed at maximum operating pressure at an elevated temperature to accelerate aging. The test was performed in two phases. The first phase, 130 F, a moderately accelerated test designed to achieve the midpoint of the model predicted point reliability. The more aggressive second phase, performed at 160 F was designed to determine if the test article will exceed the 95% confidence interval of the model. This paper will discuss the results of this test, it's implications and possible follow-on testing.

Russell, Richard; Flynn, Howard; Forth, Scott; Greene, Nathanael; Kezian, Michael; Varanauski, Don; Yoder, Tommy; Woodworth, Warren

2009-01-01

399

Rupture of an evaporating liquid bridge between two grains  

NASA Astrophysics Data System (ADS)

The study examines rupture of evaporating liquid bridges between two glass spheres. Evolution of the bridge profile has been recorded with the use of high-speed camera. Geometrical characteristics of the bridge were then used to calculate evolution of the variables during the process: Laplace pressure, capillary force, and surface tension force. For the purpose of reference, the bridge evolution is followed also during kinematic extension. During both processes the diameter of the neck decreases, with an acceleration of about 1-2 ms before the rupture. Two distinct rupture modes are observed, depending on the bridge aspect ratio. After the rupture, the mass of liquid splits, forming two separate oscillating drops attached to the spheres, and a suspended satellite droplet. Just before the rupture, an increasing repulsive Laplace pressure, and decreasing negative surface tension force develop. Capillary force follows the trend of the surface tension force, with an accelerating decline. Duration of the whole process and liquid mass stabilization is from 10 to 60 ms.

Mielniczuk, Boleslaw; El Youssoufi, Moulay Said; Sabatier, Laurent; Hueckel, Tomasz

2014-10-01

400

Mucus Rupture in A Collapsed airway: An Experimental Study  

NASA Astrophysics Data System (ADS)

Mucus plugs can completely obstruct an airway. Difficulty in mucus clearance results in lost gas exchange and inflammation. Non-Newtonian properties of mucus, yielding stress and shear-thinning, play significant roles in mucus clearance. We use aqueous carbopol 940 as a mucus stimulant to study clearance of a mucus plug with properties of yielding stress and shear-thinning in a bench-top experiment. A collapsed airway of the 12^th generation in a human lung is simulated in a two-dimensional PDMS channel. A stable pressure drop is set along the plug to drive rupture. A micro-PIV technique is used to acquire velocity fields during the rupture process. A yielding pressure drop (initiating plug yielding) is nearly independent of initial plug length. Plug rupture can occur by focused deformation along the centerline or by total plug propagation where the trailing film is thicker than the precursor film. Maximum velocity appears at the rupture moment, and increases at higher pressure drop or smaller plug length. The wall shear gradient can undergo a rapid reversal when rupture occurs, possibly an injurious event to underlying airway epithelial cells.

Hu, Yingying; Bian, Shiyao; Grotberg, James B.

2011-11-01

401

Factors affecting formation and rupture of intracranial saccular aneurysms.  

PubMed

Unruptured intracranial aneurysms represent a decisional challenge. Treatment risks have to be balanced against an unknown probability of rupture. A better understanding of the physiopathology is the basis for a better prediction of the natural history of an individual patient. Knowledge about the possible determining factors arises from a careful comparison between ruptured versus unruptured aneurysms and from the prospective observation and analysis of unbiased series with untreated, unruptured aneurysms. The key point is the correct identification of the determining variables for the fate of a specific aneurysm in a given individual. Thus, the increased knowledge of mechanisms of formation and eventual rupture of aneurysms should provide significant clues to the identification of rupture-prone aneurysms. Factors like structural vessel wall defects, local hemodynamic stress determined also by peculiar geometric configurations, and inflammation as trigger of a wall remodeling are crucial. In this sense the study of genetic modifiers of inflammatory responses together with the computational study of the vessel tree might contribute to identify aneurysms prone to rupture. The aim of this article is to underline the value of a unifying hypothesis that merges the role of geometry, with that of hemodynamics and of genetics as concerns vessel wall structure and inflammatory pathways. PMID:24306170

Bacigaluppi, S; Piccinelli, M; Antiga, L; Veneziani, A; Passerini, T; Rampini, P; Zavanone, M; Severi, P; Tredici, G; Zona, G; Krings, T; Boccardi, E; Penco, S; Fontanella, M

2014-01-01

402

Robustness Tests for Reliably Determining the Earthquake Rupture Process  

NASA Astrophysics Data System (ADS)

Problems related to the determination of the earthquake rupture process details from analysis of body-wave seismograms was first discussed by Kostrov in 1974. We discuss how to use robustness tests to identify the reliable properties of the rupture process obtained from inversion of broadband body wave data (Das and Kostrov, JGR 1990; PEPI 1994). We then interpret the results for the following submarine subduction zone earthquakes: the Mw 8.0 Andreanof Islands earthquake (Das and Kostrov, ibid.), the Mw 8.2 Biak, Indonesia earthquake (Das et al., JGR, 2000) and the Mw 8.4 2001 Peru earthquake (Robinson et al., Science, 2006), in terms of subducting seafloor features and its influence on the earthquake rupture process. In particular, subducting seamounts appear to be affecting the rupture process of all these great earthquakes. The question of how much of a seamount still remains after it is subducted to be able to affect the earthquake rupture on the subduction plane will be addressed.

Das, S.; Robinson, D.

2007-12-01

403

Radiographic Risk Factors for Contralateral Rupture in Dogs with Unilateral Cranial Cruciate Ligament Rupture  

PubMed Central

Background Complete cranial cruciate ligament rupture (CR) is a common cause of pelvic limb lameness in dogs. Dogs with unilateral CR often develop contralateral CR over time. Although radiographic signs of contralateral stifle joint osteoarthritis (OA) influence risk of subsequent contralateral CR, this risk has not been studied in detail. Methodology/Principal Findings We conducted a retrospective longitudinal cohort study of client-owned dogs with unilateral CR to determine how severity of radiographic stifle synovial effusion and osteophytosis influence risk of contralateral CR over time. Detailed survival analysis was performed for a cohort of 85 dogs after case filtering of an initial sample population of 513 dogs. This population was stratified based on radiographic severity of synovial effusion (graded on a scale of 0, 1, and 2) and severity of osteophytosis (graded on a scale of 0, 1, 2, and 3) of both index and contralateral stifle joints using a reproducible scoring method. Severity of osteophytosis in the index and contralateral stifles was significantly correlated. Rupture of the contralateral cranial cruciate ligament was significantly influenced by radiographic OA in both the index and contralateral stifles at diagnosis. Odds ratio for development of contralateral CR in dogs with severe contralateral radiographic stifle effusion was 13.4 at one year after diagnosis and 11.4 at two years. Odds ratio for development of contralateral CR in dogs with severe contralateral osteophytosis was 9.9 at one year after diagnosis. These odds ratios were associated with decreased time to contralateral CR. Breed, age, body weight, gender, and tibial plateau angle did not significantly influence time to contralateral CR. Conclusion Subsequent contralateral CR is significantly influenced by severity of radiographic stifle effusion and osteophytosis in the contralateral stifle, suggesting that synovitis and arthritic joint degeneration are significant factors in the disease mechanism underlying the arthropathy. PMID:25254499

Chuang, Connie; Ramaker, Megan A.; Kaur, Sirjaut; Csomos, Rebecca A.; Kroner, Kevin T.; Bleedorn, Jason A.; Schaefer, Susan L.; Muir, Peter

2014-01-01

404

Slip reactivation during the 2011 Tohoku earthquake: Dynamic rupture and ground motion simulations  

NASA Astrophysics Data System (ADS)

The 2011 Mw9 Tohoku earthquake generated such as vast geophysical data that allows studying with an unprecedented resolution the spatial-temporal evolution of the rupture process of a mega thrust event. Joint source inversion of teleseismic, near-source strong motion and coseismic geodetic data , e.g [Lee et. al, 2011], reveal an evidence of slip reactivation process at areas of very large slip. The slip of snapshots of this source model shows that after about 40 seconds the big patch above to the hypocenter experienced an additional push of the slip (reactivation) towards the trench. These two possible repeating slip exhibited by source inversions can create two waveform envelops well distinguished in the ground motion pattern. In fact seismograms of the KiK-Net Japanese network contained this pattern. For instance a seismic station around Miyagi (MYGH10) has two main wavefronts separated between them by 40 seconds. A possible physical mechanism to explain the slip reactivation could be a thermal pressurization process occurring in the fault zone. In fact, Kanamori & Heaton, (2000) proposed that for large earthquakes frictional melting and fluid pressurization can play a key role of the rupture dynamics of giant earthquakes. If fluid exists in a fault zone, an increase of temperature can rise up the pore pressure enough to significantly reduce the frictional strength. Therefore, during a large earthquake the areas of big slip persuading strong thermal pressurization may result in a second drop of the frictional strength after reaching a certain value of slip. Following this principle, we adopt for slip weakening friction law and prescribe a certain maximum slip after which the friction coefficient linearly drops down again. The implementation of this friction law has been done in the latest unstructured spectral element code SPECFEM3D, Peter et. al. (2012). The non-planar subduction interface has been taken into account and place on it a big asperity patch inside areas of big slip (>50m) close to the trench. Within the first 2km bellow the trench a negative stress drop has been imposed in order to represent the energy absorption zone that attenuates a high frequency radiation at the shallow part of the suduction zone. At down dip, where high frequency radiation burst has been detected from back projection techniques, e.g. [Meng et. al, 2011; Ishi , 2011], small asperities has been considered in our dynamic rupture model. Finally, a comparison of static geodetic free surface displacement and synthetics has been made to obtain our best model. We additionally compare seismograms with the aim to represent the main features of the strong ground motion recorded from this earthquake. Moreover, the spatial-temporal rupture evolution detected by back projection at down dip is in a good agreement with the rupture evolution of our dynamic model.

Galvez, P.; Dalguer, L. A.

2013-12-01

405

Barium granuloma of the transverse colon.  

PubMed Central

A case of barium sulphate granuloma of the transverse colon following gunshot wounds to the abdomen has been described. Scanning electron microscopy with electron probe microanalysis was used to confirm the presence of barium sulphate and the absence of lead or other elements related to the gunshot wounds. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:740599

McKee, P. H.; Cameron, C. H.

1978-01-01

406

Measuring transverse shape with virtual photons  

SciTech Connect

A two-dimensional Fourier transform of hadron form factors allows to determine their charge density in transverse space. We show that this method can be applied to any virtual photon induced transition, such as {gamma}{sup *}(q)+N{yields}{pi}N. Only Fock states that are common to the initial and final states contribute to the amplitudes, which are determined by the overlap of the corresponding light-front wave functions. Their transverse extent may be studied as a function of the final state configuration, allowing qualitatively new insight into strong interaction dynamics. Fourier transforming the cross section (rather than the amplitude) gives the distribution of the transverse distance between the virtual photon interaction vertices in the scattering amplitude and its complex conjugate. While the measurement of parton distributions in longitudinal momentum depends on the leading twist approximation (-q{sup 2}{yields}{infinity} limit), all q{sup 2}<0 values contribute to the Fourier transform, with the transverse resolution increasing with the available range in q{sup 2}. We illustrate the method using QED amplitudes.

Hoyer, Paul; Kurki, Samu [Department of Physics and Helsinki Institute of Physics, POB 64, University of Helsinki, FIN-00014 Helsinki (Finland)

2011-06-01

407

Transverse instability digital damper for the Recycler  

SciTech Connect

Transverse beam instability of a coasting beam with a digital damper is examined. Threshold of instability is calculated in specific cases with Landau damping taken into account. The results are applied to the Fermilab Recycler Ring. Some improvement of existing RR damper is proposed.

Balbekov, V.; /Fermilab

2006-02-01

408

Semi-Inclusive DIS and Transversity  

E-print Network

A review is presented of some aspects of semi-inclusive deeply inelastic scattering and transversity. In particular, the role of $k_T$-dependent and higher-twist (or multi-parton) distributions in generating single-spin asymmetries is discussed.

Ratcliffe, P G

2004-01-01

409

Semi-Inclusive DIS and Transversity  

SciTech Connect

A review is presented of some aspects of semi-inclusive deeply inelastic scattering and transversity. In particular, the role of kT-dependent and higher-twist (or multi-parton) distributions in generating single-spin asymmetries is discussed.

Ratcliffe, Philip G. [Dipartimento di Fisica e Matematica, Universita degli Studi dell Insubria, Istituto Navonale di Fisica Nucleare, Sezione di Milano (Italy)

2005-02-10

410

Semi-Inclusive DIS and Transversity  

NASA Astrophysics Data System (ADS)

A review is presented of some aspects of semi-inclusive deeply inelastic scattering and transversity. In particular, the role of kT-dependent and higher-twist (or multi-parton) distributions in generating single-spin asymmetries is discussed.

Ratcliffe, Philip G.

2005-02-01

411

CORONAL MAGNETOGRAPHY FROM QUASI -TRANSVERSE PROPAGATION  

E-print Network

magnetography for the microwave wavelength range: - quantitative analysis of the circularly polarized free the radio maps of a microwave source at a set of wavelengths (Brosius et al., 1997); - field measurements of quasi-transverse (QT-) propagation of microwaves in the low solar corona and some coronal magnetograms

Ryabov, Boris I.

412

Transverse Vibration of an Axially Accelerating String  

Microsoft Academic Search

The transverse vibration of an axially accelerating string is investigated. The equation of motion is developed using Hamilton's principle. The resulting partial differential equations are discretized using Galerkin's method. Assuming the axial velocity to be periodic, a stability analysis is performed using Floquet theory. One-, two-, three-, four-, six- and eight-term series approximations are considered in the Galerkin's method. The

M. Pakdemirli; A. G. Ulsoy; A. Ceranoglu

1994-01-01

413

The Transverse Proximity Effect in Quasar Spectra  

E-print Network

The Transverse Proximity Effect in Quasar Spectra G麓abor Worseck Astrophysikalisches Institut field generated by the overall population of quasars and star-forming galaxies. In the vicinity of sources of UV photons, such as luminous high-redshift quasars, the UV radiation field is enhanced due

414

Complicated malaria and a covert ruptured spleen: a case report.  

PubMed

Spontaneous splenic rupture in complicated malaria is an uncommon cause of hemoperitoneum in the tropics. The exact incidence of splenic rupture is unknown, largely due to under-reporting, but has been estimated at ?2%. Its pathophysiology is linked to the formation of a subcapsular hematoma. Upon rupture, patients present with features of shock and peritonitis and in most cases (95%), computed tomography (CT) scan detects the splenic injury. Patients should be managed conservatively with splenectomy reserved for patients with shock and hemoperitoneum due to risk of post-splenectomy sepsis. We report the case of a 38-year-old man with severe malaria who presented with fever, chills and abdominal pains. A CT scan abdomen failed to reveal splenic parenchymal injury or any splenic extravasation of contrast. Conservative management was unsuccessful. Exploratory laparatomy confirmed the spleen as the site of bleeding necessitating a splenectomy. PMID:25395608

Waweru, Peter; Macleod, Jana; Gikonyo, Anthony

2014-01-01

415

Complicated malaria and a covert ruptured spleen: a case report  

PubMed Central

Spontaneous splenic rupture in complicated malaria is an uncommon cause of hemoperitoneum in the tropics. The exact incidence of splenic rupture is unknown, largely due to under-reporting, but has been estimated at ?2%. Its pathophysiology is linked to the formation of a subcapsular hematoma. Upon rupture, patients present with features of shock and peritonitis and in most cases (95%), computed tomography (CT) scan detects the splenic injury. Patients should be managed conservatively with splenectomy reserved for patients with shock and hemoperitoneum due to risk of post-splenectomy sepsis. We report the case of a 38-year-old man with severe malaria who presented with fever, chills and abdominal pains. A CT scan abdomen failed to reveal splenic parenchymal injury or any splenic extravasation of contrast. Conservative management was unsuccessful. Exploratory laparatomy confirmed the spleen as the site of bleeding necessitating a splenectomy.

Waweru, Peter; Macleod, Jana; Gikonyo, Anthony

2014-01-01

416

Emergency Stenting of a Ruptured Infected Anastomotic Femoral Pseudoaneurysm  

SciTech Connect

A 74-year-old man presented with a ruptured infected anastomotic femoral pseudoaneurysm. Due to severe medical comorbidities he was considered unsuitable for conventional surgical management and underwent an emergency endovascular repair with a balloon-expandable covered stent. The pseudoaneurysm was excluded successfully and the patient had an uneventful postoperative recovery with long-term suppressive antimicrobials. He remained well for 10 months after the procedure with no signs of recurrent local or systemic infection and finally died from an acute myocardial infarction. To our knowledge, emergency endovascular treatment of a free ruptured bleeding femoral artery pseudoaneurysm has not been documented before in the English literature. This case illustrates that endovascular therapy may be a safe and efficient alternative in the emergent management of ruptured infected anastomotic femoral artery pseudoaneurysms when traditional open surgery is contraindicated.

Klonaris, Chris, E-mail: chris_klonaris@yahoo.com; Katsargyris, Athanasios; Matthaiou, Alexandros; Giannopoulos, Athanasios; Tsigris, Chris; Papadopouli, Katerina ['LAIKON' Hospital, Athens University Medical School, 1st Department of Surgery, Vascular Division (Greece); Tsiodras, Sotiris [Attikon Hospital, Athens University Medical School, 4th Academic Department of Internal Medicine (Greece); Bastounis, Elias ['LAIKON' Hospital, Athens University Medical School, 1st Department of Surgery, Vascular Division (Greece)

2007-11-15

417

Cecal rupture in foals -- 7 cases (1996-2006)  

PubMed Central

The objective of this study was to identify risk factors and describe clinical signs in 7 foals with cecal rupture; none of the foals survived. Six foals had undergone general anesthesia; 5 for orthopedic procedures. Six of the foals were receiving nonsteriod anti-inflammatory drugs. Most foals started showing colic signs on day 2 after surgery, preceded in 3 cases by dullness. Cecal rupture occurred between 4 hours and 2 days after the first signs of colic were noticed. Intestinal motility was decreased or absent in all foals for which it was recorded. Foals undergoing general anesthesia should be closely monitored for any sign of dullness, prolonged recumbency, reduced fecal output, and signs of abdominal discomfort for 3 days postoperatively, especially in cases following orthopedic surgery. If any of the above occurs, cecal impaction should be considered as a differential diagnosis. A prompt exploratory laparotomy may be a reasonable diagnostic option before the cecum ruptures with fatal consequences. PMID:19337616

Tabar, Juan J.; Cruz, Antonio M.

2009-01-01

418

Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing  

NASA Technical Reports Server (NTRS)

This paper reports stress rupture testing of Kevlar(TradeMark) composite overwrapped pressure vessels (COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm (40-in.) diameter Kevlar(TradeMark) COPV was tested to failure (burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

2010-01-01

419

Spin resonance strength calculations  

SciTech Connect

In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

Courant,E.D.

2008-10-06

420

Cognitive impairments after surgical repair of ruptured and unruptured aneurysms  

PubMed Central

OBJECTIVES桾o determine the frequency and severity of neuropsychological impairments associated with aneurysmal subarachnoid haemorrhage, and associated with repair of intracerebral aneurysms.?METHODS桾wo groups of patients who underwent repair of intracerebral aneurysms were studied: patients with unruptured aneurysms (n=20) and patients with ruptured aneurysms (n=27). All patients were administered a battery of standardised neuropsychological tests about 3 months after surgery. A subset of 12 patients with unruptured aneurysms were administered the battery both before and after elective repair of the aneurysm(s). A subset of six patients with ruptured aneurysms were given the test at both 3 months and 1year after surgery.?RESULTS桝s previously reported for patients with ruptured aneurysms, patients with both ruptured and unruptured aneurysms performed, as a group, significantly below published norms on many of the neuropsychological tests after surgery. However, there were significant differences between preoperative and postoperative performance in the unruptured aneurysm group only on a few tests: measures of word fluency, verbal recall, and frontal lobe function. Performance of patients with ruptured aneurysms was significantly below that of patients with unruptured aneurysms only on a few tests of verbal and visual memory. In addition, group differences compared with published norms reflected severely impaired performance by a minority of patients, rather than moderately impaired performance in a majority of patients.?CONCLUSIONS桝lthough patients who undergo repair of ruptured aneursyms perform, as a group, below published norms on many neuropsychological tests, significant impairments are seen in a minority of patients. Some of the impairments are associated with subarachnoid haemorrhage, whereas others (found in patients who underwent repair of unruptured aneurysms) are due to general effects of neurosurgery and perioperative management. Finally, some of the postoperative deficits are merely a reflection of premorbid weaknesses.?? PMID:11032612

Hillis, A.; Anderson, N.; Sampath, P.; Rigamonti, D.

2000-01-01