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Sample records for transverse rupture strength

  1. Influence of Diamond Particles Coated with TiO2 Film on Wettability of Vitrified Bond and Transverse Rupture Strength (TRS) of Vitrified Bond Composites

    NASA Astrophysics Data System (ADS)

    Song, Dongdong; Wan, Long; Liu, Xiaopan; Hu, Weida; Li, Jianwei

    2016-06-01

    TiO2 films were prepared on the surface of the diamond particles using a classical sol-gel method. The results showed that the TiO2 covered on the diamond surface as a rough and dense film with anatase phase, and tightly combined with the diamond substrates via the Ti-O-C bond. The initial oxidation temperature and compression strength of diamond were improved to 725 °C and 23.8 N with TiO2 film coated. TiO2 film increased the roughness of the diamond surface, promoted its mutual solubility, and formed the chemical bonding (Ti-O-Si) between the vitrified bond and the diamond. Therefore, the TiO2 film decreased the interface energy of the diamond, and promoted the wetting angle of vitrified bond with diamond to 36.7°. As a result, the TRS of vitrified bond diamond composites was increased to 76.3 MPa.

  2. Stress-rupture strength of alloy 718

    SciTech Connect

    Kennedy, R.L.; Cao, W.D.; Thomas, W.M.

    1996-03-01

    Alloy 718 is the most widely used of the nickel-base superalloys in aerospace applications such as compressor and turbine disks, cases, compressor blades and fasteners in aircraft gas-turbine engines. Since the development of the superalloy by Inco Alloys International over 30 years ago, researchers have made many slight modifications in chemical composition, and have refined process techniques to achieve further improvements in performance. Relatively little information on the effects of phosphorus has been published, and the available information is contradictory. However, phosphorus in superalloys is generally considered detrimental, and by specification is controlled to a low maximum value (0.015% max, for example, in AMS5662 E). This lack of data is the basis of a study by Teledyne Allvac to determine the effects of the interaction of phosphorus, boron, and carbon on the mechanical properties, processing characteristics, and microstructure of Allvac 718. Results show that a significant improvement in stress-rupture properties over those of a commercial Alloy 718 material is possible by optimizing phosphorus, boron, and carbon additions.

  3. Severe neonatal complication of transverse lie after preterm premature rupture of membranes.

    PubMed

    Van der Kaay, D C M; Horsch, S; Duvekot, J J

    2013-07-08

    Both transverse lie and preterm premature rupture of membranes (PPROM) are associated with neonatal morbidity and mortality. We present a neonate born at 29 weeks gestation with severe birth trauma after PPROM and transverse lie. The patient had extensive swelling and areas of desquamated and necrotic skin of the right lower limb. Neonatal compartment syndrome (NCS) was suspected. Perfusion of the limb improved after decompressing subcutaneous incisions. A fetus in transverse lie may be mechanically damaged in the case of PPROM, especially at an early gestational age. Early recognition is of great interest in the management and prognosis of NCS.

  4. In Vitro Study of Transverse Strength of Fiber Reinforced Composites

    PubMed Central

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

    2011-01-01

    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 (3×2×25 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’s 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

  5. The in situ transverse lamina strength of composite laminates

    NASA Technical Reports Server (NTRS)

    Flaggs, D. L.

    1983-01-01

    The objective of the work reported in this presentation is to determine the in situ transverse strength of a lamina within a composite laminate. From a fracture mechanics standpoint, in situ strength may be viewed as constrained cracking that has been shown to be a function of both lamina thickness and the stiffness of adjacent plies that serve to constrain the cracking process. From an engineering point of view, however, constrained cracking can be perceived as an apparent increase in lamina strength. With the growing need to design more highly loaded composite structures, the concept of in situ strength may prove to be a viable means of increasing the design allowables of current and future composite material systems. A simplified one dimensional analytical model is presented that is used to predict the strain at onset of transverse cracking. While it is accurate only for the most constrained cases, the model is important in that the predicted failure strain is seen to be a function of a lamina's thickness d and of the extensional stiffness bE theta of the adjacent laminae that constrain crack propagation in the 90 deg laminae.

  6. Prediction of residual tensile strength of transversely impacted composite laminates

    NASA Technical Reports Server (NTRS)

    Lal, K. M.

    1982-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

  8. Characterisation of Laves phase precipitation and its correlation to creep rupture strength of ferritic steels

    SciTech Connect

    Zhu, S.; Yang, M.; Song, X.L.; Tang, S.; Xiang, Z.D.

    2014-12-15

    The Laves phase precipitation process was characterised by means of field emission scanning electron microscopy to demonstrate its effect on creep rupture strength of steels with a fully ferritic matrix. To eliminate the effects of carbide and carbonitride precipitations so that the creep rupture data can be analysed exclusively in relation to the Laves phase precipitation process, an alloy Fe–9Cr–3Co–3W (wt.%) without C and N additions was used for the study. Creep rupture strengths were measured and volume fraction and particle size of Laves phase precipitates in the ruptured specimens were analysed. It was found that the creep rupture strength started to collapse (or decrease more rapidly) long before the Laves phase precipitation reached equilibrium fraction. This was related to the onset of the coarsening of Laves phase particles, which precipitated only on grain boundaries and hence contributed little to precipitation strengthening. Creep deformation had no effect either on the precipitation kinetics or on the growth kinetics of Laves phase particles. - Highlights: • Laves phase precipitation at 650 °C was characterised for Fe–9Cr–3W–3Co alloy. • Laves phase precipitated predominantly on grain boundaries. • Creep deformation had no effect on Laves phase precipitation and growth kinetics. • Creep strength started to collapse long before Laves phase precipitation is ended. • Collapse of creep strength was attributed to the coarsening of Laves phase particles.

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

    USGS Publications Warehouse

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

    1996-01-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    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).

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

    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 δ-ferrite content, alignment of columnar grain with δ-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.

  12. Rupture Strength of Several Nickel-base Alloys in Sheet Form

    NASA Technical Reports Server (NTRS)

    Dance, James H; Clauss, Francis J

    1957-01-01

    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.

  13. Comparison of the Tensile, Creep, and Rupture Strength Properties of Stoichiometric SiC Fibers

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    Tensile strength, creep strength, and rupture strength properties were measured for the following types of polymer-derived stoichiometric SiC fibers: Hi-Nicalon Type S from Nippon Carbon, Tyranno SA from Ube, and Sylramic from Dow Corning. Also included in this study were an earlier version of the SA fiber plus two recent developmental versions of the Sylramic fiber. The tensile strength measurements were made at room temperature on as-received fibers and on fibers after high-temperature inert exposure. The creep-rupture property data were obtained at 1400 deg C in air as well as, argon. Some fiber types showed strong effects of environment on their strength properties. These results are compared and discussed in terms of underlying mechanisms and implications for ceramic composites.

  14. A comparative study of the stress-rupture lifetimes of high-strength carbon fibers

    NASA Astrophysics Data System (ADS)

    Grimes-Ledesma, Lorie

    Stress-rupture life is the time a composite can survive under load at an assigned risk level. The stress-rupture lifetimes of high-strength PAN-based carbon fibers are important to the development and use of lightweight composite structures such as composite overwrapped pressure vessels (COPVs). To quantify appropriate stress-rupture risk levels based on available models, quantification of single fiber variability and lifetime is necessary to understand the variability observed in larger composite structures. In the present work, three PAN-based carbon fibers commonly used in COPV technology were examined, Hexcel IM9, Toray T700, and Toray T1000. The diameter of each fiber type was quantified by measuring samples in the scanning electron microscope and failure loads were determined by performing tensile tests on single fibers. Weibull statistics were used to describe the results. Fractography was performed on IM9 and T1000 fibers after tensile failure. The fracture surfaces are consistent with crack growth from a volume or surface defect. Stress-rupture testing was completed at two stress levels at each fiber type, 97% and 93% of the mean fiber strength for each of the fiber types. The results indicate that differences in stress-rupture life performance exist between the three fiber types. Differences in stress ratio of between 5 and 10% were observed, which may translate to significant difference in stress-rupture life behavior for larger composite structures. The results indicate that a relationship may exist between strength and stress-rupture life. However, if this relationship exists, it is not a simple one, and the relationship is likely complicated by manufacturing.

  15. The Inclusion of Arbitrary Load Histories in the Strength Decay Model for Stress Rupture

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2014-01-01

    Stress rupture is a failure mechanism where failures can occur after a period of time, even though the material has seen no increase in load. Carbon/epoxy composite materials have demonstrated the stress rupture failure mechanism. In a previous work, a model was proposed for stress rupture of composite overwrap pressure vessels (COPVs) and similar composite structures based on strength degradation. However, the original model was limited to constant load periods (holds) at constant load. The model was expanded in this paper to address arbitrary loading histories and specifically the inclusions of ramp loadings up to holds and back down. The broadening of the model allows for failures on loading to be treated as any other failure that may occur during testing instead of having to be treated as a special case. The inclusion of ramps can also influence the length of the "safe period" following proof loading that was previously predicted by the model. No stress rupture failures are predicted in a safe period because time is required for strength to decay from above the proof level to the lower level of loading. Although the model can predict failures during the ramp periods, no closed-form solution for the failure times could be derived. Therefore, two suggested solution techniques were proposed. Finally, the model was used to design an experiment that could detect the difference between the strength decay model and a commonly used model for stress rupture. Although these types of models are necessary to help guide experiments for stress rupture, only experimental evidence will determine how well the model may predict actual material response. If the model can be shown to be accurate, current proof loading requirements may result in predicted safe periods as long as 10(13) years. COPVs design requirements for stress rupture may then be relaxed, allowing more efficient designs, while still maintaining an acceptable level of safety.

  16. Creep and Rupture Strength of an Advanced CVD SiC Fiber

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    In the as-produced condition the room temperature strength (approx. 6 GPa) of Textron Specialty Materials' 50 microns CVD SiC fiber represents the highest value thus far obtained for commercially produced polycrystalline SiC fibers. To understand whether this strength can be maintained after composite processing conditions, high temperature studies were performed on the effects of time, stress, and environment on 1400 deg. C tensile creep strain and stress rupture on as-produced, chemically vapor deposited SiC fibers. Creep strain results were consistent, allowing an evaluation of time and stress effects. Test environment had no influence on creep strain but I hour annealing at 1600 deg. C in argon gas significantly reduced the total creep strain and increased the stress dependence. This is attributed to changes in the free carbon morphology and its distribution within the CVD SiC fiber. For the as-produced and annealed fibers, strength at 1400 deg. C was found to decrease from a fast fracture value of 2 GPa to a 100-hr rupture strength value of 0. 8 GPa. In addition a loss of fast fracture strength from 6 GPa is attributed to thermally induced changes in the outer carbon coating and microstructure. Scatter in rupture times made a definitive analysis of environmental and annealing effects on creep strength difficult.

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

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2012-01-01

    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

  18. Copper, Boron, and Cerium Additions in Type 347 Austenitic Steel to Improve Creep Rupture Strength

    NASA Astrophysics Data System (ADS)

    Laha, Kinkar; Kyono, J.; Shinya, Norio

    2012-04-01

    Type 347 austenitic stainless steel (18Cr-12Ni-Nb) was alloyed with copper (3 wt pct), boron (0.01 to 0.06 wt pct), and cerium (0.01 wt pct) with an aim to increase the creep rupture strength of the steel through the improved deformation and cavitation resistance. Short-term creep rupture strength was found to increase with the addition of copper in the 347 steel, but the long-term strength was inferior. Extensive creep cavitation deprived the steel of the beneficial effect of creep deformation resistance induced by nano-size copper particles. Boron and cerium additions in the copper-containing steel increased its creep rupture strength and ductility, which were more for higher boron content. Creep deformation, grain boundary sliding, and creep cavity nucleation and growth in the steel were found to be suppressed by microalloying the copper-containing steel with boron and cerium, and the suppression was more for higher boron content. An auger electron spectroscopic study revealed the segregation of boron instead of sulfur on the cavity surface of the boron- and cerium-microalloyed steel. Cerium acted as a scavenger for soluble sulfur in the steels through the precipitation of cerium sulfide (CeS). This inhibited the segregation of sulfur and facilitated the segregation of boron on cavity surface. Boron segregation on the nucleated cavity surface reduced its growth rate. Microalloying the copper-containing 347 steel with boron and cerium thus enabled to use the full extent of creep deformation resistance rendered by copper nano-size particle by increase in creep rupture strength and ductility.

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

    NASA Technical Reports Server (NTRS)

    Gray, H. H.

    1976-01-01

    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.

  20. The Reinforcement Effect of Nano-Zirconia on the Transverse Strength of Repaired Acrylic Denture Base.

    PubMed

    Gad, Mohammed; ArRejaie, Aws S; Abdel-Halim, Mohamed Saber; Rahoma, Ahmed

    2016-01-01

    Objective. The aim of this study was to evaluate the effect of incorporation of glass fiber, zirconia, and nano-zirconia on the transverse strength of repaired denture base. Materials and Methods. Eighty specimens of heat polymerized acrylic resin were prepared and randomly divided into eight groups (n = 10): one intact group (control) and seven repaired groups. One group was repaired with autopolymerized resin while the other six groups were repaired using autopolymerized resin reinforced with 2 wt% or 5 wt% glass fiber, zirconia, or nano-zirconia particles. A three-point bending test was used to measure the transverse strength. The results were analyzed using SPSS and repeated measure ANOVA and post hoc least significance (LSD) test (P ≤ 0.05). Results. Among repaired groups it was found that autopolymerized resin reinforced with 2 or 5 wt% nano-zirconia showed the highest transverse strength (P ≤ 0.05). Repairs with autopolymerized acrylic resin reinforced with 5 wt% zirconia showed the lowest transverse strength value. There was no significant difference between the groups repaired with repair resin without reinforcement, 2 wt% zirconia, and glass fiber reinforced resin. Conclusion. Reinforcing of repair material with nano-zirconia may significantly improve the transverse strength of some fractured denture base polymers.

  1. The Reinforcement Effect of Nano-Zirconia on the Transverse Strength of Repaired Acrylic Denture Base

    PubMed Central

    ArRejaie, Aws S.; Abdel-Halim, Mohamed Saber; Rahoma, Ahmed

    2016-01-01

    Objective. The aim of this study was to evaluate the effect of incorporation of glass fiber, zirconia, and nano-zirconia on the transverse strength of repaired denture base. Materials and Methods. Eighty specimens of heat polymerized acrylic resin were prepared and randomly divided into eight groups (n = 10): one intact group (control) and seven repaired groups. One group was repaired with autopolymerized resin while the other six groups were repaired using autopolymerized resin reinforced with 2 wt% or 5 wt% glass fiber, zirconia, or nano-zirconia particles. A three-point bending test was used to measure the transverse strength. The results were analyzed using SPSS and repeated measure ANOVA and post hoc least significance (LSD) test (P ≤ 0.05). Results. Among repaired groups it was found that autopolymerized resin reinforced with 2 or 5 wt% nano-zirconia showed the highest transverse strength (P ≤ 0.05). Repairs with autopolymerized acrylic resin reinforced with 5 wt% zirconia showed the lowest transverse strength value. There was no significant difference between the groups repaired with repair resin without reinforcement, 2 wt% zirconia, and glass fiber reinforced resin. Conclusion. Reinforcing of repair material with nano-zirconia may significantly improve the transverse strength of some fractured denture base polymers. PMID:27366150

  2. The Reinforcement Effect of Nano-Zirconia on the Transverse Strength of Repaired Acrylic Denture Base.

    PubMed

    Gad, Mohammed; ArRejaie, Aws S; Abdel-Halim, Mohamed Saber; Rahoma, Ahmed

    2016-01-01

    Objective. The aim of this study was to evaluate the effect of incorporation of glass fiber, zirconia, and nano-zirconia on the transverse strength of repaired denture base. Materials and Methods. Eighty specimens of heat polymerized acrylic resin were prepared and randomly divided into eight groups (n = 10): one intact group (control) and seven repaired groups. One group was repaired with autopolymerized resin while the other six groups were repaired using autopolymerized resin reinforced with 2 wt% or 5 wt% glass fiber, zirconia, or nano-zirconia particles. A three-point bending test was used to measure the transverse strength. The results were analyzed using SPSS and repeated measure ANOVA and post hoc least significance (LSD) test (P ≤ 0.05). Results. Among repaired groups it was found that autopolymerized resin reinforced with 2 or 5 wt% nano-zirconia showed the highest transverse strength (P ≤ 0.05). Repairs with autopolymerized acrylic resin reinforced with 5 wt% zirconia showed the lowest transverse strength value. There was no significant difference between the groups repaired with repair resin without reinforcement, 2 wt% zirconia, and glass fiber reinforced resin. Conclusion. Reinforcing of repair material with nano-zirconia may significantly improve the transverse strength of some fractured denture base polymers. PMID:27366150

  3. Determination of transverse shear strength through torsion testing

    SciTech Connect

    Marcucelli, K.T.; Fish, J.C.

    1997-12-31

    The in-plane characterization of composite materials is, in general, well understood and widely utilized throughout the aerospace industry. However, the use of composites in structural elements such as fuselage frames and rotorcraft flexbeams place large out-of-plane or through-the-thickness stresses for which there is little data. Efforts to determine the interlaminar shear strength of laminated composites have been hampered due to the nonlinear behavior of test specimens and the limitations of current analysis tools. An inexpensive rectangular torsion test specimen was designed to determine the interlaminar shear strength, s{sub 23}, of composite materials. Six different layups were fabricated of AS4/2220-3 carbon/epoxy unidirectional tape and tested in pure torsion. All of the specimens failed abruptly with well-defined shear cracks and exhibited linear load-deflection behavior. A quasi-three-dimensional (Q-3-D) finite element analysis was conducted on each of the specimen configurations to determine the interlaminar shear stress at failure. From this analysis, s{sub 23} was found to be 107 MPa for this material.

  4. Scale effects on the transverse tensile strength of graphite epoxy composites

    NASA Technical Reports Server (NTRS)

    Obrien, T. Kevin; Salpekar, Satish A.

    1992-01-01

    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.

  5. Comparisons of 76Hz transverse and radial magnetic field strength components received in Connecticut

    NASA Astrophysics Data System (ADS)

    Bannister, P. R.

    1986-03-01

    Since June 1970, we have made extremely low frequency (ELF) measurements of the transverse horizontal magnetic field strength, H sub phi, received in Connecticut. Occasionally, we also have measured either the vertical electric field strength, E sub v, or the radial horizontal magnetic field strength, H sub rho. The AN/BSR-1 ELF receivers are located at the Naval Underwater Systems Center (NUSC), at New London, CT. The transmission source for these farfield (1.6-Mm range) measurements is the U.S. Navy's ELF Wisconsin Test Facility (WTF), located in the Chequamegon National Forest in north-central Wisconsin. The results of 136 days of radial magnetic field measurements taken from November 1977 through June 1984 are discussed in this report. The main result is that during disturbed propagation conditions, the radial and transverse magnetic field strength daily plots (versus GMT) are usually dissimilar (in both amplitude and relative phase).

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

    SciTech Connect

    Kumar, Sanjeev; Thomas, K. J.; Smith, L. W.; Farrer, I.; Ritchie, D. A.; Jones, G. A. C.; Griffiths, J.; Pepper, M.

    2013-12-04

    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.

  7. Running exercises improve the strength of a partially ruptured Achilles tendon

    PubMed Central

    See, E; Ng, G; Ng, C; Fung, D

    2004-01-01

    Objectives: To examine the effects of running and swimming exercises on the functional performance and mechanical strength of a recovering Achilles tendon. Methods: 30 Sprague-Dawley rats had surgical transection of their right medial Achilles tendon. The rats were divided into running (n = 11), swimming (n = 10), and control (n = 9) groups. The running and swimming groups were given daily exercise training, starting from the fifth day after the injury; the control group did not exercise throughout the period of the experiment. An Achilles functional index (AFI) was recorded before the operation and on the third, 10th, and 30th days after the operation. On the 30th day, the rats were killed and their Achilles tendons harvested for biomechanical testing of load relaxation properties, stiffness, and ultimate tensile strength (UTS). The AFI data were analysed by two way analysis of variance; load relaxation, stiffness, and UTS data were analysed by multivariate analysis, with α at 0.05. Results: The UTS of the running group was higher than in the control group (p = 0.015), while there was no significant difference between the swimming and control groups (p = 0.228). Differences in stiffness and load relaxation were non-significant (p = 0.823 and 0.633, respectively). The AFI results did not differ among the three groups (p = 0.242). Conclusions: Running exercises can improve the strength of partially ruptured Achilles tendons at 30 days after injury. PMID:15388547

  8. Shear strength of shock-loaded alumina as determined with longitudinal and transverse manganin gauges

    NASA Astrophysics Data System (ADS)

    Rosenberg, Z.; Yaziv, D.; Yeshurun, Y.; Bless, S. J.

    1987-08-01

    The shear strength of shock-loaded commercial alumina (AD-85 manufactured by Coors) is determined in the 0-140-kbar range of shock stresses. Longitudinal and transverse manganin gauges were used to determine the principal stresses in the shocked specimens. Shear strengths were determined from the difference between the longitudinal and lateral stresses. It was found that the shear strength remains essentially constant at about 27 kbar for shock stresses between 60 kbar (the Hugoniot elastic limit) and the maximum shock amplitude tested in this series (142 kbar). The source for the high shear strength is attributed to the confining pressures that strengthen the comminuted ceramic. Evidence for this interpretation is obtained by considering the release profiles as recorded by the longitudinal gauges when the free-surface rarefactions reach gauge location.

  9. Time-Dependent Stress Rupture Strength Degradation of Hi-Nicalon Fiber-Reinforced Silicon Carbide Composites at Intermediate Temperatures

    NASA Technical Reports Server (NTRS)

    Sullivan, Roy M.

    2016-01-01

    The stress rupture strength of silicon carbide fiber-reinforced silicon carbide composites with a boron nitride fiber coating decreases with time within the intermediate temperature range of 700 to 950 degree Celsius. Various theories have been proposed to explain the cause of the time-dependent stress rupture strength. The objective of this paper is to investigate the relative significance of the various theories for the time-dependent strength of silicon carbide fiber-reinforced silicon carbide composites. This is achieved through the development of a numerically based progressive failure analysis routine and through the application of the routine to simulate the composite stress rupture tests. The progressive failure routine is a time-marching routine with an iterative loop between a probability of fiber survival equation and a force equilibrium equation within each time step. Failure of the composite is assumed to initiate near a matrix crack and the progression of fiber failures occurs by global load sharing. The probability of survival equation is derived from consideration of the strength of ceramic fibers with randomly occurring and slow growing flaws as well as the mechanical interaction between the fibers and matrix near a matrix crack. The force equilibrium equation follows from the global load sharing presumption. The results of progressive failure analyses of the composite tests suggest that the relationship between time and stress-rupture strength is attributed almost entirely to the slow flaw growth within the fibers. Although other mechanisms may be present, they appear to have only a minor influence on the observed time-dependent behavior.

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

    NASA Technical Reports Server (NTRS)

    OBrien, T. Kevin; Krueger, Ronald

    2001-01-01

    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.

  11. Creep-Rupture Strength of a Ni-Base Superalloy at 1400 K

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Nathal, Michael V.; Book, Patricia O.

    1993-01-01

    While NASAIR 100 is not the strongest of elevated-temperature single-crystal alloys, its higher-temperature properties are indicative of this technology's behavior. Attention is presently given to test results for this alloy which illuminate its 1400 K creep failure properties in air, and furnish a benchmark for the comparison of advanced materials to existing technology. The creep rupture behavior resembles that found after 1273 K testing, and is indicative of gamma-prime strengthening.

  12. Effects of Heterogeneities in Strength and Initial Shear Stress on Large Ruptures in a Fast Multi-cycle Earthquake Simulator (RSQSim) and DYNA3D

    NASA Astrophysics Data System (ADS)

    Stevens, J.; Richards-Dinger, K.; Dieterich, J.; Oglesby, D.

    2008-12-01

    RSQSim is a fast earthquake simulator that produces long (~ 106 event and ~ 104 year) synthetic seismicity catalogs in complex fault systems. It treats the interseismic and nucleation phases of the seismic cycle quasi-statically with an approximate version of rate- and state-dependent friction. The ruptures themselves are quasi-dynamic with slip speeds determined by shear impedance considerations. Validation of coseismic final slip (and therefore stress change) distributions is important for the generation of long catalogs because subsequent events in such simulators need to inherit the proper stress fields. Also, the heterogeneous evolved stress states from long simulations in complex fault systems (resulting from complex large ruptures, ongoing smaller seismicity, and stress interactions within the fault system) may be useful as more realistic inputs to dynamic rupture modelling. If the time evolution of ruptures in RSQSim is also realistic, they may be useful as kinematic sources for seismic hazard ground motion calculations. As part of an effort to validate the quasi-dynamic ruptures in RSQSim, we compare rupture propagation on a variable-strength planar fault in RSQSim to that on a similar fault in DYNA3D (a fully dynamic finite element model employing slip-weakening friction) for single, large, artificially nucleated ruptures. Previous work has shown that on homogeneous planar faults the RSQSim results agreed quantitatively very well with those of DYNA3D. For this comparison, our asperity model consists of multiple rectangular zones of increased normal stress of varying size, location, and amplitude. The heterogeneities produce complex ruptures - the rupture front tends to wrap itself around the barriers and create a burst of energy once it propagates across a barrier. Both codes allow rupture propagation over significant zones of negative stress drop in these asperity regions. Rupture durations, average rupture propagation speeds, and overall slip pattern

  13. Effect of repair surface design, repair material, and processing method on the transverse strength of repaired acrylic denture resin.

    PubMed

    Ward, J E; Moon, P C; Levine, R A; Behrendt, C L

    1992-06-01

    The transverse strengths of blocks of denture base acrylic resin repaired with autopolymerizing monomer and polymer and autopolymerizing monomer and heat-cured polymer were measured with a three-point bending test. Three repair joints were studied: butt, round, and 45-degree bevel. Three processing methods were used: bench cure, hydroflask with hot water for 10 minutes, and hydroflask with hot water for 30 minutes. The strengths of repairs made with round and 45-degree bevel joint designs were similar and significantly greater than those with a butt joint design. The strengths of repairs processed in a hydroflask for 10 minutes and 30 minutes were similar and significantly greater than those cured on the bench top. There was no difference in the strength of repairs made with autopolymerizing monomer and polymer and autopolymerizing monomer and heat-cured polymer.

  14. 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

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

    2013-08-01

    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

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

    USGS Publications Warehouse

    Frankel, A.

    1991-01-01

    The high-frequency falloff ??-y 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, D being the fractal dimension. In the model, an earthquake is composed of a hierarchical set of smaller earthquakes. The static stress drop is parameterized to be proportional to R??, and strength is assumed to be proportional to static stress drop. I find that a distribution of subevents with D = 2 and stress drop independent of seismic moment (?? = 0) produces a main shock with an ??-2 falloff, if the subevent areas fill the rupture area of the main shock. By equating subevents to "islands' of high stress of a random, self-similar stress field on a fault, I relate D to the scaling of strength on a fault, such that D = 2 - ??. Thus D = 2 corresponds to constant stress drop scaling (?? = 0) and scale-invariant fault strength. A self-similar model of aftershock rupture zones on a fault is used to determine the relationship between the b value, the size distribution of aftershock rupture zones, and the scaling of strength on a fault. -from Author

  16. Glass rupture disk

    DOEpatents

    Glass, S. Jill; Nicolaysen, Scott D.; Beauchamp, Edwin K.

    2002-01-01

    A frangible rupture disk and mounting apparatus for use in blocking fluid flow, generally in a fluid conducting conduit such as a well casing, a well tubing string or other conduits within subterranean boreholes. The disk can also be utilized in above-surface pipes or tanks where temporary and controllable fluid blockage is required. The frangible rupture disk is made from a pre-stressed glass with controllable rupture properties wherein the strength distribution has a standard deviation less than approximately 5% from the mean strength. The frangible rupture disk has controllable operating pressures and rupture pressures.

  17. Temperature Dependence on the Strength and Stress Rupture Behavior of a Carbon-Fiber Reinforced Silicon Carbide (C/SiC) Composite

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Calomino, Anthony

    2002-01-01

    Tensile strengths and stress rupture lives of carbon-fiber reinforced silicon carbide (C/SiC) specimens were measured at 800 C and are compared to previously reported 1200 C data. All tests were conducted in an environmental chamber containing 1000 ppm of oxygen in argon. The average 800 C tensile strength of 610 MPa is 10% greater than at 1200 C. Average stress rupture lives at 800 C were 2.5 times longer than those obtained at 1200 C. The difference in the 800 and 1200 C lives is related to the oxidation rate of the reinforcing carbon fibers, which is the primary damage mode of C/SiC composites in oxygen-containing environments.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  19. Three-Dimensional Gait Analysis Following Achilles Tendon Rupture With Nonsurgical Treatment Reveals Long-Term Deficiencies in Muscle Strength and Function

    PubMed Central

    Tengman, Tine; Riad, Jacques

    2013-01-01

    Background: Precise long-term assessment of movement and physical function following Achilles tendon rupture is required for the development and evaluation of treatment, including different regimens of physical therapy. Purpose: To assess intermediate-term (<10 years by conventional thinking) objective measures of physical function following Achilles tendon rupture treated nonsurgically and to compare these with self-reported measures of physical function. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Two to 5 years after Achilles tendon rupture, 9 women and 43 men (mean age, 49.2 years; range, 26-68 years) were assessed by physical examination, performance of 1-legged jumps, and 3-dimensional gait analysis (including calculation of muscle work). Self-reported scores for foot function (Achilles tendon rupture score) and level of physical activity were collected. Twenty age- and sex-matched controls were assessed in the same manner. Results: Physical examination of patients with the knee extended revealed 11.1° of dorsiflexion on the injured side and 9.2° on the uninjured side (P = .020), indicating gastrocnemius muscle lengthening. The 1-legged jump distance was shorter on the injured side (89.5 vs 96.2 cm; P < .001). Gait analysis showed higher peak dorsiflexion (14.3° vs 13.3°; P = .016) and lower concentric (positive) plantar flexor work (16.6 vs 19.9 J/kg; P = .001) in the ankle on the uninjured side. At the same time, eccentric (negative) dorsiflexor work was higher on the injured side (13.2 vs 11.9 J/kg; P = .010). Self-perceived foot function and physical activity were lower in patients than in healthy controls (mean Achilles tendon rupture score, 78.6 and 99.8, respectively). Conclusion: Nonsurgically treated patients with Achilles tendon rupture showed signs of both anatomic and functional lengthening of the tendon. Attenuated muscle strength and function were present during walking as long as 2 to 5 years after rupture, as

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

    PubMed Central

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

    2013-01-01

    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 (α= 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

  1. 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)

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

    2014-05-01

    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.

  2. In-vitro Evaluation of Transverse Strength of Repaired Heat Cured Denture Base Resins without Surface Treatment and with Chemical and Mechanical Surface Treatment

    PubMed Central

    Yadav, Naveen S; Khare, Shilpi; Mishra, Sunil Kumar; Vyas, Rajesh; Mahajan, Harsh; Chitumalla, Rajkiran

    2015-01-01

    Background: Denture repair involves joining two parts of a fractured denture with a denture repair material. Hence, a substantial repairing system for denture base fracture should be there to elude frequent fracture. Materials and Methods: Surface treatment of conventional heat cure denture base resin with different surface treatments (chemical ethyl acetate, and mechanical roughening with bur), with control group formed without surface treatment. Specimens were repaired with auto polymerizing acrylic resin using sprinkle on technique. The testing of the transverse strength of the repaired specimens was evaluated with three-point bending test on universal testing machine. Results: The study revealed that surface chemical treatment with ethyl acetate improved the transverse strength of repaired heat cure denture base when compared with mechanical and control group. A two-way analysis of variance revealed that there was statistically significant difference in mean strengths of the three groups. Conclusion: Surface chemical treatment with ethyl acetate improved the transverse strength of the repaired heat cure denture base when compared with mechanical roughening with bur and group without surface treatment. PMID:26464547

  3. Heat-to-Heat Variation in Creep Life and Fundamental Creep Rupture Strength of 18Cr-8Ni, 18Cr-12Ni-Mo, 18Cr-10Ni-Ti, and 18Cr-12Ni-Nb Stainless Steels

    NASA Astrophysics Data System (ADS)

    Abe, Fujio

    2016-09-01

    Metallurgical factors causing the heat-to-heat variation in time to rupture have been investigated for 300 series stainless steels for boiler and heat exchanger seamless tubes, 18Cr-8Ni (JIS SUS 304HTB), 18Cr-12Ni-Mo (JIS SUS 316HTB), 18Cr-10Ni-Ti (JIS SUS321 HTB), and 18Cr-12Ni-Nb (JIS SUS 347HTB), at 873 K to 1023 K (600 °C to 750 °C) using creep rupture data for nine heats of the respective steels in the NIMS Creep Data Sheets. The maximum time to rupture was 222,705.3 hours. The heat-to-heat variation in time to rupture of the 304HTB and 316HTB becomes more significant with longer test durations at times above ~10,000 hours at 973 K (700 °C) and reaches to about an order of magnitude difference between the strongest and weakest heats at 100,000 hours, whereas that of the 321HTB and 347HTB is very large of about an order of magnitude difference from a short time of ~100 hours to long times exceeding 100,000 hours at 873 K to 973 K (600 °C to 700 °C). The heat-to-heat variation in time to rupture is mainly explained by the effect of impurities: Al and Ti for the 304HTB and 316HTB, which reduces the concentration of dissolved nitrogen available for the creep strength by the formation of AlN and TiN during creep, and boron for the 347HTB, which enhances fine distributions of M23C6 carbides along grain boundaries. The heat-to-heat variation in time to rupture of the 321HTB is caused by the heat-to-heat variation in grain size, which is inversely proportional to the concentration of Ti. The fundamental creep rupture strength not influenced by impurities is estimated for the steels. The 100,000 hours-fundamental creep rupture strength of the 347HTB steel is lower than that of 304HTB and 316HTB at 873 K and 923 K (600 °C and 650 °C) because the slope of stress vs time to rupture curves is steeper in the 347HTB than in the 304HTB and 316HTB. The 100,000 hours-fundamental creep rupture strength of the 321HTB exhibits large variation depending on grain size.

  4. Densification, microstructure and strength evolution in sintering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoping

    2000-10-01

    Powder metallurgy has the ability to fabricate high quality, complex components to close tolerances in an economical manner. In many applications, a high sintered density is desirable for an improved performance. However, sintering to a high density demands a large shrinkage, often resulting in difficulties with dimensional control. Recent studies indicate the occurrence of a sufficient densification requires a low in situ strength at high sintering temperatures. On the other hand, the low in situ strength often leads to component's distortion in response to the external forces, such as gravity. Unfortunately, lack of knowledge on strength evolution in sintering has been a major challenge to achieve an optimized combination of densification and shape retention. Therefore, the present study investigates strength evolution in sintering and the effects of processing factors. Experiments are performed on prealloyed bronze and elemental mixture of Fe-2Ni powders. For the bronze, a loose casting method is used to fabricate transverse rupture bars, while bars are injection molded for the Fe-2Ni. The in situ transverse rupture strength is measured using the Penn State Flaming Tensile Tester. Experimental results indicate a dependence of densification and strength on sintering temperature. High temperatures enhance densification and interparticle bonding, resulting in strong sintered structures. However, a low in situ strength at high test temperatures indicates the dominance of thermal softening. A strength model combining sintering theories and microstructural parameters is developed to predict both the in situ strength and the post-sintering strength. The model demonstrates the strength of the sintered materials depends on the inherent material strength, the square of neck size ratio, sintered density, and thermal softening. The model is verified by comparison of model predictions with experimental data of the bronze and Fe-2Ni. Compared to prior strength models, this

  5. Centrally-Rupturing Squib-Closure Disks

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1986-01-01

    Rupture-disk design makes squib action more predictable. In new design, center of rupture disk contains cruciform indentation in which thickness reduced to about 0.5 mil (0.013 mm). Reduces strength of center of rupture disk in same manner as that of pull tabs on beverage cans; therefore, disk will fail predictably in center.

  6. Rupture disc

    DOEpatents

    Newton, Robert G.

    1977-01-01

    The intermediate heat transport system for a sodium-cooled fast breeder reactor includes a device for rapidly draining the sodium therefrom should a sodium-water reaction occur within the system. This device includes a rupturable member in a drain line in the system and means for cutting a large opening therein and for positively removing the sheared-out portion from the opening cut in the rupturable member. According to the preferred embodiment of the invention the rupturable member includes a solid head seated in the end of the drain line having a rim extending peripherally therearound, the rim being clamped against the end of the drain line by a clamp ring having an interior shearing edge, the bottom of the rupturable member being convex and extending into the drain line. Means are provided to draw the rupturable member away from the drain line against the shearing edge to clear the drain line for outflow of sodium therethrough.

  7. Describing Soils: Calibration Tool for Teaching Soil Rupture Resistance

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  8. 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

    Oborn, B. M.; Metcalfe, P. E.; Butson, M. J.; Rosenfeld, A. B.

    2010-10-15

    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

  9. [A simplified technique for repair of quadriceps tendon rupture by transpatellar PDS-cord].

    PubMed

    Hosseini, H; Agneskirchner, J D; Lobenhoffer, P

    2005-06-01

    Quadriceps tendon ruptures are relatively unusual injuries caused by direct or more frequently indirect trauma. Since complete ruptures lead to loss of active extension of the knee joint, operative treatment is usually indicated. Several techniques are described in the literature. However, relatively little is known about the functional outcome after operative treatment of acute quadriceps tendon ruptures. We present a new operative technique using a 1.3-mm PDS cord passed through a transverse drill hole in the proximal pole of the patella. We operated ten consecutive cases of complete quadriceps tendon ruptures with the technique described between January 2000 and June 2003. Eight of ten patients were evaluated after a mean follow-up time of 38 months by physical examination, IKDC Subjective score, Lysholm and Tegner score as well as an isokinetic test of the quadriceps strength. No complications were noted in this period. The average postoperative scores were 87 (IKDC), 98 (Lysholm), and 4.5 (Tegner). Isokinetic testing showed an average of 25% quadriceps strength deficit. The operative treatment of complete quadriceps tendon ruptures using a PDS cord through a drill hole in the patella is a safe and effective technique permitting functional postoperative treatment.

  10. Quadriceps and patellar tendon rupture.

    PubMed

    Ramseier, L E; Werner, C M L; Heinzelmann, M

    2006-06-01

    Ruptures of the patellar and/or quadriceps tendon are rare injuries that require immediate repair to re-establish knee extensor continuity and to allow early motion. We evaluated 36 consecutive patients with quadriceps or patellar tendon rupture between 1993 and 2000. There were 37 primary ruptures, 3 reruptures, 21 quadriceps and 19 patellar tendon ruptures. Follow up examination (>24 months postoperatively) included the patient's history, assessment of risk factors, clinical examination of both knees, isometric muscle strength measurements and three specific knee scores, Hospital for Special Surgery Score, Knee Society Score and Turba Score, and a short form SF-36. We evaluated 29 patients (26 men) with 33 ruptures (16 patellar tendon, 17 quadriceps tendon). Seven patients were lost to follow up. We found no difference between the range of motion and muscle strength when the injured leg was compared to the non-injured leg. Risk factors did not influence the four scores, patient satisfaction, pain, muscle strength or range of motion. Multiple injured patients had a significant reduction in muscle strength and circumference, however patient satisfaction did not differ to the non-multiple injured patient group.

  11. Flexor digitorum superficialis rupture: a case report.

    PubMed

    Culver, J E

    1976-04-01

    A rupture of the musculotendinous junction of the flexor digitorum superficialis to the index finger in a baseball pitcher is described. No underlying abnormality could be detected. Because of loss of strength and dexterity, repair of the rupture was accomplished with an improved result.

  12. The effects of barriers on supershear rupture

    NASA Astrophysics Data System (ADS)

    Xu, Jiankuan; Zhang, Zhenguo; Chen, Xiaofei

    2016-07-01

    A barrier may induce a supershear rupture transition in some cases, whereas it may prevent the further propagation of a supershear rupture in other cases. We investigate the effects of a barrier on the supershear rupture propagation on a planar fault in a 3-D half-space. Our results show that the effect of a barrier on supershear is strongly dependent on its size, strength, and location. For larger sizes, shallower buried depths, and relatively higher strengths, the barrier tends to prevent supershear propagation more strongly. When the barrier is located on the free surface and near the critical distance, it prevents the further propagation of supershear rupture. If a barrier is located far from the critical distance, the first supershear daughter crack is slowed down and a new supershear daughter crack is generated after the rupture front passes through the barrier. This mechanism greatly lengthens the supershear transition distance.

  13. Biomechanical rupture risk assessment of abdominal aortic aneurysms based on a novel probabilistic rupture risk index.

    PubMed

    Polzer, Stanislav; Gasser, T Christian

    2015-12-01

    A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach. PMID:26631334

  14. Transversity 2005

    NASA Astrophysics Data System (ADS)

    Barone, Vincenzo; Ratcliffe, Philip G.

    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

  15. Transversity 2008

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    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. Käfer (for the COMPASS collaboration

  16. Patellar and quadriceps tendon ruptures--jumper's knee.

    PubMed

    Kelly, D W; Carter, V S; Jobe, F W; Kerlan, R K

    1984-01-01

    We reviewed 13 patients with end stage jumper's knee, 10 with patellar tendon ruptures, and 3 with ruptures of the quadriceps tendon to evaluate our long-term results in treating these tendon ruptures in an athletic population. The focus was on the natural history, the time until return, and the level of return, to athletic activity. Jumper's knee affected all patients to a varying degree prior to rupture. Basketball was the most common sport involved. At followup, averaging 4 1/2 years, patients underwent functional and clinical, as well as Cybex and roentgenographic, evaluations. Results indicated patellar tendon ruptures, where the ruptures are complete, have a more favorable prognosis than those of the quadriceps tendon which are incomplete. All of the latter patients continued to have quadriceps tendinitis following repair. In both groups, the poor results were obtained in patients with chondromalacia and/or patella alta. Cybex testing yielded results of greater than 100% strength in three patients with patellar tendon ruptures, but no patient with quadriceps rupture had comparable test results. There was no apparent relationship between ruptures and cortisone injections. Patellar and quadriceps tendon ruptures from indirect injury in athletes represent the end stage of jumper's knee and result from repetitive microtrauma. Excellent function usually follows repair of patellar tendon ruptures when surgery is performed early and care is taken to restore normal patellar tendon length. Results of quadriceps ruptures are less satisfactory since these ruptures are usually incomplete and all degenerative tissue may not be involved in the healing response.

  17. Transverse myelitis

    SciTech Connect

    Black, M.J.; Motaghedi, B.; Robitaille, Y.

    1980-05-01

    Transverse myelitis is a known complication of radiation treatment for carcinoma of the heat and neck. In a five year period, 1970 to 1975, 120 patients with head and neck cancer received radiation as part of their treatment in this hospital. A review of the records of these patients showed only two cases of myelitis, an incidence of about 2%. This paper reviews the clinical syndrome; treatment and preventive measures are discussed and a survey of the literature is presented.

  18. Transverse Myelitis

    MedlinePlus

    ... Later, if patients begin to recover limb control, physical therapy begins to help improve muscle strength, coordination, and ... therapists, vocational therapists, and mental health care professionals. Physical Therapy : Physiatrists and physical therapists treat disabilities that result ...

  19. Creep-rupture of polymer-matrix composites. [graphite-epoxy laminates

    NASA Technical Reports Server (NTRS)

    Brinson, H. F.; Griffith, W. I.; Morris, D. H.

    1980-01-01

    An accelerated characterization method for resin matrix composites is reviewed. Methods for determining modulus and strength master curves are given. Creep rupture analytical models are discussed as applied to polymers and polymer matrix composites. Comparisons between creep rupture experiments and analytical models are presented. The time dependent creep rupture process in graphite epoxy laminates is examined as a function of temperature and stress level.

  20. Fan-structure waves in shear ruptures

    NASA Astrophysics Data System (ADS)

    Tarasov, Boris

    2016-04-01

    This presentation 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. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength), self-sustaining stress intensification in the rupture tip (providing easy formation of new slabs), and self-unbalancing conditions in the fan-head (making the failure process inevitably spontaneous and violent). An important feature of the fan-mechanism is the fact that for the initial formation of the fan-structure an enhanced local shear stress is required, however, after completion of the fan-structure it can propagate as a dynamic wave through intact rock mass at shear stresses below the frictional strength. Paradoxically low shear strength of pristine rocks provided by the fan-mechanism determines the correspondingly low transient strength of the lithosphere, which favours generation of new earthquake faults in the intact rock mass adjoining pre-existing faults in preference to frictional stick-slip instability along these faults. The new approach reveals an alternative role of pre-existing faults in earthquake activity: they represent local stress concentrates in pristine rock adjoining the fault where special conditions for the fan-mechanism nucleation are created, while further dynamic propagation of the new fault (earthquake) occurs at low field stresses even below the frictional strength.

  1. LOX Tank Rupture

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The bright luminous glow at the top is attributed to the rupture of the liquid oxygen tank just above the SRB/ET attachment. At this point, Challenger is completely engulfed in a firey flow of escaping liquid propellant.

  2. Achilles tendon rupture - aftercare

    MedlinePlus

    Heel cord tear; Calcaneal tendon rupture ... MRI scan to see what type of Achilles tendon tear you have. An MRI is a type ... partial tear means at least some of the tendon is still OK. A full tear means your ...

  3. Rupture Paths in Kappa-Maps: Quantitative Insights on Heterogeneous Earthquake Ruptures From Energy Arguments.

    NASA Astrophysics Data System (ADS)

    Ampuero, J.; Ripperger, J.; Mai, M.

    2005-12-01

    Earthquake rupture is a notoriously complex process, at all observable scales. Although heterogeneities of strength and initial stress contribute to this rupture complexity, a systematic approach to quantify their effect has not yet been attempted. For instance, little is known about the relation between the final size of an earthquake and the statistical properties of initial strength excess fields. Canonical cases of dynamic rupture (e.g. uniform initial stress and friction properties), can be characterized by two non-dimensional numbers: the S-parameter (ratio of strength excess to stress drop) and the Kappa-parameter (ratio of static energy release rate to fracture energy, Madariaga and Olsen, 2000). The latter was introduced as a global parameter, involving the fault depth or asperity size as the fundamental scale. However, because faults contain heterogeneities at all scales it is not clear how a single scale-length may be relevant to define Kappa. We define here a scale-dependent Kappa-map, based on classical energy concepts in fracture mechanics. In 2D these maps can be defined exactly, and their efficient computation is implemented as a series of FFT-convolutions, by scaled analytical filters related to stress intensity factor weight functions. For given heterogeneous stress drop and fracture energy, such Kappa-maps are useful to predict nucleation properties and final moment, as we illustrate through increasingly complex examples complemented by dynamic rupture simulations. Other properties that can be derived from the 2D Kappa-maps, with additional assumptions, include radiated energy and rupture directivity. In 3D, the shape of the rupture front is unknown a priori and the energy release rate G might be non-uniform along the front. We therefore propose an approximate definition of Kappa in which G is estimated on circular patches. Comparisons with 3D dynamic rupture simulations on highly heterogeneous initial stress fields show that the final moment can

  4. Biomechanical Rupture Risk Assessment

    PubMed Central

    2016-01-01

    Abdominal aortic aneurysm (AAA) rupture is a local event in the aneurysm wall that naturally demands tools to assess the risk for local wall rupture. Consequently, global parameters like the maximum diameter and its expansion over time can only give very rough risk indications; therefore, they frequently fail to predict individual risk for AAA rupture. In contrast, the Biomechanical Rupture Risk Assessment (BRRA) method investigates the wall’s risk for local rupture by quantitatively integrating many known AAA rupture risk factors like female sex, large relative expansion, intraluminal thrombus-related wall weakening, and high blood pressure. The BRRA method is almost 20 years old and has progressed considerably in recent years, it can now potentially enrich the diameter indication for AAA repair. The present paper reviews the current state of the BRRA method by summarizing its key underlying concepts (i.e., geometry modeling, biomechanical simulation, and result interpretation). Specifically, the validity of the underlying model assumptions is critically disused in relation to the intended simulation objective (i.e., a clinical AAA rupture risk assessment). Next, reported clinical BRRA validation studies are summarized, and their clinical relevance is reviewed. The BRRA method is a generic, biomechanics-based approach that provides several interfaces to incorporate information from different research disciplines. As an example, the final section of this review suggests integrating growth aspects to (potentially) further improve BRRA sensitivity and specificity. Despite the fact that no prospective validation studies are reported, a significant and still growing body of validation evidence suggests integrating the BRRA method into the clinical decision-making process (i.e., enriching diameter-based decision-making in AAA patient treatment).

  5. Creep rupture behavior of Stirling engine materials

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  6. The mechanical properties of prematurely and non--prematurely ruptured membranes. Methods and preliminary results.

    PubMed

    Artal, R; Sokol, R J; Neuman, M; Burstein, A H; Stojkov, J

    1976-07-01

    The mechanical properties of the chorioamniotic membranes have been studied by several investigators over the past 100 years. No relationship between membrane strength, as measured by rupture tension, and premature or non-premature rupture of the membranes has been demonstrable. In the present study, several measures of the mechanical properties of the chorioamniotic membranes were examined. These included thickness, rupture tension, work to rupture, strain to rupture, and moduli of elasticity (Young). Prematurely and non-prematurely ruptured membranes differed with respect to thickness near the rupture site and Young's modulus near the placenta. Differences between the groups for the other parameters were not significant. This study suggests that there may be inherent differences between membranes which rupture prematurely and those which do not.

  7. Achilles Tendon Rupture

    PubMed Central

    Wertz, Jess; Galli, Melissa; Borchers, James R.

    2013-01-01

    Context: Achilles tendon (AT) rupture in athletes is increasing in incidence and accounts for one of the most devastating sports injuries because of the threat to alter or end a career. Despite the magnitude of this injury, reliable risk assessment has not been clearly defined, and prevention strategies have been limited. The purpose of this review is to identify potential intrinsic and extrinsic risk factors for AT rupture in aerial and ground athletes stated in the current literature. Evidence Acquisition: A MEDLINE search was conducted on AT rupture, or “injury” and “risk factors” and “athletes” from 1980 to 2011. Emphasis was placed on epidemiology, etiology, and review articles focusing on the risk for lower extremity injury in runners and gymnasts. Thirty articles were reviewed, and 22 were included in this assessment. Results: Aerial and ground athletes share many intrinsic risk factors for AT rupture, including overuse and degeneration of the tendon as well as anatomical variations that mechanically put an athlete at risk. Older athletes, athletes atypical in size for their sport, high tensile loads, leg dominance, and fatigue also may increase risk. Aerial athletes tend to have more extrinsic factors that play a role in this injury due to the varying landing surfaces from heights and technical maneuvers performed at various skill levels. Conclusion: Risk assessment for AT rupture in aerial and ground athletes is multivariable and difficult in terms of developing prevention strategies. Quantitative measures of individual risk factors may help identify major contributors to injury. PMID:24427410

  8. Premature rupture of membranes

    MedlinePlus

    ... the 37th week of pregnancy, it is called preterm premature rupture of membranes (PPROM). The earlier your water breaks, the more ... babies born early). If there is not a preterm unit where you deliver, you and your baby will be moved to a hospital that has one.

  9. [Stomach rupture while diving].

    PubMed

    Russi, E; Gäumann, N; Geroulanos, S; Bühlmann, A A

    1985-06-01

    A case of stomach rupture in a 47-year-old scuba diver is reported. Symptoms of gastrointestinal expansion during ascent are quite common and are caused by decompression of swallowed air. Gastric perforation is however rare, and needs to be promptly recognized and surgically repaired.

  10. Labyrinthine window rupture.

    PubMed

    Fraser, J G; Harborow, P C

    1975-01-01

    Some cases of sensorineural deafness are due to labyrinthine window rupture. Three cases have been presented to illustrate different aspects of diagnosis and managment of this condition. The indications for surgical intervention have been discussed. The importance of making the diagnosis is that operation can relieve vertigo and restore the hearing.

  11. Coupling geodynamic earthquake cycles and dynamic ruptures

    NASA Astrophysics Data System (ADS)

    van Zelst, Iris; van Dinther, Ylona; Gabriel, Alice-Agnes; Heuret, Arnauld

    2016-04-01

    Studying the seismicity in a subduction zone and its effects on tsunamis requires diverse modelling methods that span spatial and temporal scales. Hundreds of years are necessary to build the stresses and strengths on a fault, while consequent earthquake rupture propagation is determined by both these initial fault conditions and the feedback of seismic waves over periods of seconds up to minutes. This dynamic rupture displaces the sea floor, thereby causing tsunamis. The aim of the ASCETE (Advanced Simulations of Coupled Earthquake and Tsunami Events) project is to study all these aspects and their interactions. Here, we present preliminary results of the first aspects in this modelling chain: the coupling of a seismo-thermo-mechanical (STM) code to the dynamic rupture model SeisSol. STM models of earthquake cycles have the advantage of solving multiple earthquake events in a self-consistent manner concerning stress, strength and geometry. However, the drawback of these models is that they often lack in spatial or temporal resolution and do not include wave propagation. In contrast, dynamic rupture models solve for frictional failure coupled to seismic wave propagation. We use the software package SeisSol (www.seissol.org) based on an ADER-DG discretization allowing high-order accuracy in space and time as well as flexible tetrahedral meshing. However, such simulations require assumptions on the initial fault stresses and strengths and its geometry, which are hard to constrain due to the lack of near-field observations and the complexity of coseismic conditions. By adapting the geometry as well as the stress and strength properties of the self-consistently developing non-finite fault zones from the geodynamic models as initial conditions for the dynamic rupture models, the advantages of both methods are exploited and modelling results may be compared. Our results show that a dynamic rupture can be triggered spontaneously and that the propagating rupture is

  12. Creep rupture testing of carbon fiber-reinforced epoxy composites

    NASA Astrophysics Data System (ADS)

    Burton, Kathryn Anne

    Carbon fiber is becoming more prevalent in everyday life. As such, it is necessary to have a thorough understanding of, not solely general mechanical properties, but of long-term material behavior. Creep rupture testing of carbon fiber is very difficult due to high strength and low strain to rupture properties. Past efforts have included testing upon strands, single tows and overwrapped pressure vessels. In this study, 1 inch wide, [0°/90°]s laminated composite specimens were constructed from fabric supplied by T.D. Williamson Inc. Specimen fabrication methods and gripping techniques were investigated and a method was developed to collect long term creep rupture behavior data. An Instron 1321 servo-hydraulic material testing machine was used to execute static strength and short term creep rupture tests. A hanging dead-weight apparatus was designed to perform long-term creep rupture testing. The testing apparatus, specimens, and specimen grips functioned well. Collected data exhibited a power law distribution and therefore, a linear trend upon a log strength-log time plot. Statistical analysis indicated the material exhibited slow degradation behavior, similar to previous studies, and could maintain a 50 year carrying capacity at 62% of static strength, approximately 45.7 ksi.

  13. Reduction in the occurrence of uterine rupture in Central India.

    PubMed

    Chhabra, S; Bhagwat, N; Chakravorty, Anupama

    2002-01-01

    This study was carried out in the Department of Obstetrics and Gynaecology of the Mahatma Gandhi Institute of Medical Sciences, Sevagram in Central India. In the 12 years between 1989 and 2000 a total of 16 cases of ruptured uterus were managed, the incidence of rupture of the pregnant uterus being 0.62 per 1000 births. One-quarter of the cases occurred between 1983 and 1988. No teenager or elderly woman (over 40) or grandmultipara sustained a uterine rupture. Four women had a rupture of a previous scar. In five rupture had occurred in association with malpresentations, one was a case of hydrocephalus, two had a morbidly adherent placenta praevia and four had a normal presentation, with lack of progress in labour. Two of these 16 women had twins. One had come with a retained second twin with transverse lie and the other was a booked case with multiple problems, including a previous caesarean section, present twin pregnancy and placenta praevia accreta and she died. This was the only maternal death. Perinatal mortality was 77.77% compared to 5.88% maternal and 100% perinatal mortality in the cases reported previously between 83 and 88, from the same institution. Overall, there is some improvement in perinatal survival and one-quarter incidence of rupture of the pregnant uterus.

  14. Ligament length patterns, strength, and rotational axes of the knee joint.

    PubMed

    Trent, P S; Walker, P S; Wolf, B

    1976-06-01

    Using intact fresh specimens, the cruciate ligament lengths for positions of flexion and internal-external rotation were computed using a non-invasive technique; using photographic methods, the centers of transverse rotation on the tibia and the direction of the flexion axis were also obtained. The anterior cruciate was found to be particularly effective in restraining internal tibial rotation; the ability of the posterior cruciate to restrain external rotation, however, depended strongly on the transverse axis location. Ligament length changes during flexion were found to be small in the absence of rotary torque and anteroposterior forces. The average internal rotation occurring during flexion was 37 degrees, half of which took place during the first 15 degrees of flexion. Ultimate rupture strengths of approximately 60 kh for the cruciates were measured, with stiffnesses of 16 kg/mm.

  15. Earthquake in a Maze: Compressional Rupture Branching During the 2012 Mw 8.6 Sumatra Earthquake

    NASA Astrophysics Data System (ADS)

    Meng, L.; Ampuero, J.-P.; Stock, J.; Duputel, Z.; Luo, Y.; Tsai, V. C.

    2012-08-01

    Seismological observations of the 2012 moment magnitude 8.6 Sumatra earthquake reveal unprecedented complexity of dynamic rupture. The surprisingly large magnitude results from the combination of deep extent, high stress drop, and rupture of multiple faults. Back-projection source imaging indicates that the rupture occurred on distinct planes in an orthogonal conjugate fault system, with relatively slow rupture speed. The east-southeast-west-northwest ruptures add a new dimension to the seismotectonics of the Wharton Basin, which was previously thought to be controlled by north-south strike-slip faulting. The rupture turned twice into the compressive quadrant, against the preferred branching direction predicted by dynamic Coulomb stress calculations. Orthogonal faulting and compressional branching indicate that rupture was controlled by a pressure-insensitive strength of the deep oceanic lithosphere.

  16. Brittle dynamic damage due to earthquake rupture

    NASA Astrophysics Data System (ADS)

    Bhat, Harsha; Thomas, Marion

    2016-04-01

    The micromechanical damage mechanics formulated by Ashby and Sammis, 1990, and generalized by Deshpande and Evans 2008 has been extended to allow for a more generalized stress state and to incorporate an experimentally motivated new crack growth (damage evolution) law that is valid over a wide range of loading rates. This law is sensitive to both the crack tip stress field and its time derivative. Incorporating this feature produces additional strain-rate sensitivity in the constitutive response. The model is also experimentally verified by predicting the failure strength of Dionysus-Pentelicon marble over wide range of strain rates. We then implement this constitutive response to understand the role of dynamic brittle off-fault damage on earthquake ruptures. We show that off-fault damage plays an important role in asymmetry of rupture propagation and is a source of high-frequency ground motion in the near source region.

  17. Premature rupture of membranes.

    PubMed Central

    Poma, P. A.

    1996-01-01

    The management of patients with premature rupture of membranes has changed markedly in the past several years. The basis for this is a combination of a better understanding of newborn physiology, improved neonatal care, refinements in antibiotic therapy, and the widespread use of maternal and fetal monitoring. The best outcome for both mother and infant undoubtedly reflects data based on a combination of factors, among which are gestational age survival, evidence of fetal distress, presence or absence of labor and sepsis, and of course, the cervical condition as it is related to labor-readiness. An important recent advance is the recognition that an active observation management program is associated with less morbidity and mortality than the classic management course of delivery within 12 hours of membrane rupture. The fact that preterm premature rupture of membranes tends to recur in subsequent pregnancies offers an opportunity for prevention. Moreover, advances in perinatal and neonatal care will continue to improve the outcomes of these women and their children. PMID:8583489

  18. Rupture of bicornuate uterus

    PubMed Central

    Jayaprakash, Sheela; Muralidhar, Lakshmidevi; G, Sampathkumar; Sexsena, Rajivkumar

    2011-01-01

    A primigravida aged 20 years was referred to Vydehi Institute of Medical Sciences with diagnosis of 30 weeks of period of gestation with eclampsia and failure to respond to induction with misoprostol and she was on Pritchard regimen for the treatment of eclampsia and there was no response to induction of labour and emergency ultrasound was taken and it showed an extrauterine gestation of 30 weeks gestation with fetal demise and free fluid in peritoneum. A tentative diagnosis of secondary abdominal pregnancy with eclampsia was made and she was taken for emergency laprotomy. Intra operative findings showed haemoperitoneum, fetus with placenta and membranes in the peritoneal cavity, there was bicornuate uterus and right horn was ruptured from the fundus to about 8 cm down in the posterior aspect and ruptured part was sutured in two layers. After securing perfect haemostasis, abdomen was closed. This paper illustrates a case report of uterine anomaly with 30 weeks period of gestation and eclampsia and rupture following induction with prostaglandins. PMID:22675095

  19. Rupture of bicornuate uterus.

    PubMed

    Jayaprakash, Sheela; Muralidhar, Lakshmidevi; Sampathkumar, G; Sexsena, Rajivkumar

    2011-01-01

    A primigravida aged 20 years was referred to Vydehi Institute of Medical Sciences with diagnosis of 30 weeks of period of gestation with eclampsia and failure to respond to induction with misoprostol and she was on Pritchard regimen for the treatment of eclampsia and there was no response to induction of labour and emergency ultrasound was taken and it showed an extrauterine gestation of 30 weeks gestation with fetal demise and free fluid in peritoneum. A tentative diagnosis of secondary abdominal pregnancy with eclampsia was made and she was taken for emergency laprotomy. Intra operative findings showed haemoperitoneum, fetus with placenta and membranes in the peritoneal cavity, there was bicornuate uterus and right horn was ruptured from the fundus to about 8 cm down in the posterior aspect and ruptured part was sutured in two layers. After securing perfect haemostasis, abdomen was closed. This paper illustrates a case report of uterine anomaly with 30 weeks period of gestation and eclampsia and rupture following induction with prostaglandins. PMID:22675095

  20. Rupture of bicornuate uterus.

    PubMed

    Jayaprakash, Sheela; Muralidhar, Lakshmidevi; Sampathkumar, G; Sexsena, Rajivkumar

    2011-10-28

    A primigravida aged 20 years was referred to Vydehi Institute of Medical Sciences with diagnosis of 30 weeks of period of gestation with eclampsia and failure to respond to induction with misoprostol and she was on Pritchard regimen for the treatment of eclampsia and there was no response to induction of labour and emergency ultrasound was taken and it showed an extrauterine gestation of 30 weeks gestation with fetal demise and free fluid in peritoneum. A tentative diagnosis of secondary abdominal pregnancy with eclampsia was made and she was taken for emergency laprotomy. Intra operative findings showed haemoperitoneum, fetus with placenta and membranes in the peritoneal cavity, there was bicornuate uterus and right horn was ruptured from the fundus to about 8 cm down in the posterior aspect and ruptured part was sutured in two layers. After securing perfect haemostasis, abdomen was closed. This paper illustrates a case report of uterine anomaly with 30 weeks period of gestation and eclampsia and rupture following induction with prostaglandins.

  1. 14 CFR 23.1453 - Protection of oxygen equipment from rupture.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Protection of oxygen equipment from rupture... Equipment Miscellaneous Equipment § 23.1453 Protection of oxygen equipment from rupture. (a) Each element of the oxygen system must have sufficient strength to withstand the maximum pressure and temperature,...

  2. 14 CFR 23.1453 - Protection of oxygen equipment from rupture.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Protection of oxygen equipment from rupture... Equipment Miscellaneous Equipment § 23.1453 Protection of oxygen equipment from rupture. (a) Each element of the oxygen system must have sufficient strength to withstand the maximum pressure and temperature,...

  3. 14 CFR 23.1453 - Protection of oxygen equipment from rupture.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Protection of oxygen equipment from rupture... Equipment Miscellaneous Equipment § 23.1453 Protection of oxygen equipment from rupture. (a) Each element of the oxygen system must have sufficient strength to withstand the maximum pressure and temperature,...

  4. 14 CFR 23.1453 - Protection of oxygen equipment from rupture.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Protection of oxygen equipment from rupture... Equipment Miscellaneous Equipment § 23.1453 Protection of oxygen equipment from rupture. (a) Each element of the oxygen system must have sufficient strength to withstand the maximum pressure and temperature,...

  5. 14 CFR 23.1453 - Protection of oxygen equipment from rupture.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Protection of oxygen equipment from rupture... Equipment Miscellaneous Equipment § 23.1453 Protection of oxygen equipment from rupture. (a) Each element of the oxygen system must have sufficient strength to withstand the maximum pressure and temperature,...

  6. Slow rupture of frictional interfaces

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    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.

  7. Effects of Pre-Stress State and Rupture Velocity on Dynamic Fault Branching

    NASA Astrophysics Data System (ADS)

    Kame, N.; Rice, J. R.; Dmowska, R.

    2002-12-01

    We consider a mode II rupture which propagates along a planar main fault and encounters an intersection with a branching fault that makes an angle with the main fault. Within a formulation that allows the failure path to be dynamically self-chosen, we study the following questions: Does the rupture start along the branch? Does it continue? Which side is most favored for branching, the extensional or compressional? Does rupture continue on the main fault too? What path is finally self-chosen? Failure in the modeling is described by a slip-weakening law for which the peak and residual strength, and strength at any particular amount of slip, is proportional to normal stress. We use the elastodynamic boundary integral equation method to allow simulations of rupture along the branched fault system. Our results show that dynamic stresses around the rupturing fault tip, which increase with rupture velocity at locations off the main fault plane, relative to those on it, could initiate rupture on a branching fault. As suggested by prior work [Poliakov, Dmowska and Rice, 2002, http://esag.harvard.edu/dmowska/PDR.pdf], whether a branching rupture, once begun, can be continued to a larger scale depends on principal stress directions in the pre-stress state and on rupture velocity. The most favored side for rupture transferring on a branching fault switches from the extensional side to the compressive side as we consider progressively shallower angles of the direction of maximum pre-compression with the main fault. Simultaneous rupturing on both faults is usually difficult for a narrow branching angle due to strong stress interaction between faults, which discourages rupture continuation on the other side. However, it can be activated by enhanced dynamic stressing when the rupture velocity is very near the limiting velocity (Rayleigh wave velocity for mode II). It can also be activated when the branching angle is wide because of decreasing stress interaction between faults

  8. Nondestructive Evaluation and Monitoring Results from COPV Accelerated Stress Rupture Testing

    NASA Astrophysics Data System (ADS)

    Saulsberry, Regor L.; Greene, Nathanael J.; Banks, Curtis E.; Madaras, Eric I.; Waller, Jess M.; Forth, Scott C.; Russell, Rick W.

    2010-09-01

    To project objective is to develop and demonstrate nondestructive evaluation(NDE) techniques capable of assessing stress rupture related strength degradation for carbon composite pressure vessels, either in a structural health monitoring(SHM) or periodic inspection mode.

  9. Composite Stress Rupture NDE Research and Development Project (Kevlar[R] and Carbon)

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor

    2010-01-01

    The objective was to develop and demonstrate nondestructive evaluation (NDE) techniques capable of assessing stress rupture related strength degradation for carbon composite pressure vessels, either in a structural health monitoring (SHM) or periodic inspection mode.

  10. Ruptured tubal molar pregnancy.

    PubMed

    Yakasai, I A; Adamu, N; Galadanchi, H S

    2012-01-01

    Molar pregnancies in most instances develop within the uterine cavity, but may occur at any site. Ectopic molar pregnancy is a rare event. The objective of this study was to present a case of ruptured tubal molar gestation, discuss its clinical features and ways to improve diagnostic accuracy. A 35-year-old woman presented with features suggestive of ruptured tubal ectopic pregnancy. There was neither any evidence at the time of presentation to suspect a molar gestation, nor β human chorionic gonadotrophin (βhCG) hormone estimation was done, but only a clearview pregnancy test was carried out. She had total left salpingectomy and histological evaluation of the specimen revealed complete hydatidiform mole. The hCG level normalized within 3 weeks of follow-up. Clinical features of ectopic molar pregnancy may be indistinguishable from non-molar ectopic pregnancy. We recommend βhCG estimation as well as histological examination of the surgical specimen for all patients coming with features suggestive of ectopic pregnancy. PMID:23238205

  11. RBMK pressure tube rupture assessment

    SciTech Connect

    Schmitt, B.E.; Tsiklauri, G.V.

    1994-08-01

    The Russian RBMK reactor core design consists of multiple parallel pressure tube channels that contain Zr clad, UO{sub 2} fuel pin bundles. These parallel channels are contained within graphite moderator blocks which are, in turn, contained within a sealed core cavity. Current safety evaluation efforts of the RBMK reactors have been concentrating in the area of tube ruptures within the core cavity and, in particular, multiple tube ruptures that could threaten the reactor core integrity. Tube rupture events result in a pressurization of the reactor core cavity. The original design overpressure for the cavity region was based on a single tube rupture, resulting in considerable margin to the top plate lift pressure. The top plate lift pressure is 3.1 bar, and a single tube rupture would result in approximately 1.4 bar. RBMK plant specific cavity pressure relief designs provide for between three and in simultaneous tube ruptures before exceeding the top plate lift pressure. Thus, current safety evaluations have begun to examine the potential for multiple tube ruptures that could exceed the current cavity pressure relief designs. One such scenario being examined is a partial rupture in a group distribution header that results in stagnated (low) flow to up to 40 pressure tubes. The subsequent fuel heatup in these reduced flow tubes could result in multiple tube ruptures beyond the design relief capacity of the core cavity. This paper examines several key issues in evaluating this transient, including: (1) the effects of low flow, (2) the effects of axial peaking, and (3) the effects of radial peaking, all relative to the time to tube rupture. These issues each play a significant role in attempting to evaluate the likelihood and severity of multiple tube ruptures for a partial group distribution header break.

  12. Stress-rupture behavior of small diameter polycrystalline alumina fibers

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

  13. Rupture and healing of one-dimensional chains in a parametric magnetic ratchet potential

    NASA Astrophysics Data System (ADS)

    Tierno, Pietro; Reddy, Sathavaram V.; Johansen, Tom H.; Fischer, Thomas M.

    2007-04-01

    Transverse paramagnetic particle chains parametrically driven by a magnetic ratchet potential rupture and heal upon collision with an obstacle. The overdamped transverse dynamics is frozen during the time the particles stay in the ratchet potential wells and kicked during the time the particles hop to the next well. On time scales large compared to the parametric modulation period the healing of the hole in the chain is determined by dipolar repulsion and hydrodynamic friction of the paramagnetic particles.

  14. Spontaneous rupture on irregular faults

    NASA Astrophysics Data System (ADS)

    Liu, C.

    2014-12-01

    It is now know (e.g. Robinson et al., 2006) that when ruptures propagate around bends, the rupture velocity decrease. In the extreme case, a large bend in the fault can stop the rupture. We develop a 2-D finite difference method to simulate spontaneous dynamic rupture on irregular faults. This method is based on a second order leap-frog finite difference scheme on a uniform mesh of triangles. A relaxation method is used to generate an irregular fault geometry-conforming mesh from the uniform mesh. Through this numerical coordinate mapping, the elastic wave equations are transformed and solved in a curvilinear coordinate system. Extensive numerical experiments using the linear slip-weakening law will be shown to demonstrate the effect of fault geometry on rupture properties. A long term goal is to simulate the strong ground motion near the vicinity of bends, jogs, etc.

  15. Spontaneous Iliac Vein Rupture

    PubMed Central

    Kim, Dae Hwan; Park, Hyung Sub; Lee, Taeseung

    2015-01-01

    Spontaneous iliac vein rupture (SIVR) is a rare entity, which usually occurs without a precipitating factor, but can be a life-threatening emergency often requiring an emergency operation. This is a case report of SIVR in a 62-year-old female who presented to the emergency room with left leg swelling. Workup with contrast-enhanced computed tomography revealed a left leg deep vein thrombosis with May-Thurner syndrome and a hematoma in the pelvic cavity without definite evidence of arterial bleeding. She was managed conservatively without surgical intervention, and also underwent inferior vena cava filter insertion and subsequent anticoagulation therapy for pulmonary thromboembolism. This case shows that SIVR can be successfully managed with close monitoring and conservative management, and anticoagulation may be safely applied despite the patient presenting with venous bleeding. PMID:26217647

  16. Short-lived Supershear Rupture

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Fukuyama and Olsen (2002) computed the supershear rupture initiation, propagation and termination process due to a passage of high stress drop area (called asperity) using a boundary integral equation method. They found that supershear rupture continued to propagate after the passage through high stress drop area but it died after a certain propagation distance, which depends on the elastic energy released at the high stress drop area. Here, we could reproduce a similar phenomenon in the laboratory. We conducted large-scale biaxial friction experiments using a pair of meter-scaled metagabbro rock specimens (VP=6.9km/s, VS=3.6km/s) at the National Research institute for Earth Science and Disaster Prevention (NIED). We observed several stick slip rupture events that initiated close to an asperity and immediately became supershear ruptures. But after propagating certain distance they died out and co-existing subshear ruptures became prominent. If we look into details, during the supershear rupture, we could see a sequence of rupture acceleration, its short rest and re-acceleration. This feature reminds us of a sequential breakage of small high stress patches as predicted by Fukuyama and Madariaga (2000). These observations might be interpreted under a concept of energy balance where the energy transmission from strain energy released by the asperity to fracture energy consumed at the crack tip was not instantaneously balanced in space. This could be related to the fact that earthquake rupture velocity is rather smooth reported from the finite fault analysis of large earthquakes with seismic waveforms. References Fukuyama, E. and R. Madariaga (2000) Dynamic propagation and interaction of a rupture front on a planar fault, PAGEOPH, 257, 1959-1979. Fukuyama, E. and K.B. Olsen (2002) A condition for super-shear rupture propagation in a heterogeneous stress field, PAGEOPH, 159, 2047-2056.

  17. Barriers to faulting in the Basin-Range province: evidence from the Sou Hills transverse block

    SciTech Connect

    Fonseca, J.E.

    1985-01-01

    Transverse structural blocks may inhibit the propagation of fault ruptures in the Basin-Range province. The Sou Hills, between Dixie and Pleasant Valleys, is a block of uplifted Tertiary bedrock transverse to the NNE-SSW trend of the central Nevada seismic belt. Three lines of evidence indicate that offset due to normal faulting is much less in the Sou Hills compared to adjacent segments of the seismic belt. First, estimates of total late Cenozoic offsets of pre-extension basalts show that the total offset is less in the Sou Hills. Second, analyses of landforms that reflect rates of relative uplift show that Quaternary tectonic activity on range-bounding faults declines where faults join the Sou Hills. Third, measurements of late Quaternary fault scarps show that individual rupture segments in the Sou Hills are shorter in length and have smaller displacements compared to the nearly continuous ruptures of several meters offset found along the Tobin and Stillwater Ranges to the north and south. The Sou Hills rupture pattern is distinctive: ruptures are dispersed over a wide zone rather than being concentrated along well-defined range fronts. Normal faulting patterns produced by the 1915 Pleasant Valley, Nevada and the 1983 Borah Peak, Idaho earthquakes indicate that a discontinuous, spatially dispersed faulting style typifies ruptures which die out in transverse bedrock features. These historic analogues support a model for prehistoric faulting in which ruptures have repeatedly died out in the Sou Hills. Transverse blocks such as the Sou Hills appear to present barriers to propagating ruptures.

  18. Acute torticollis secondary to rupture of the sternocleidomastoid.

    PubMed

    Schuyler-Hacker, H; Green, R; Wingate, L; Sklar, J

    1989-11-01

    Trauma to the neck musculature and cervical spine is frequently caused by hyperextension injuries which may result in muscular spasm or rupture. Partial rupture of the sternocleidomastoid muscle with subsequent formation of a fibrotic band is an unusual cause of acute torticollis. The case of a 21-year-old man who developed an acute torticollis and cervical pain after a motor vehicle accident is presented. Computed tomography scan demonstrated 75% rupture of the left sternocleidomastoid muscle with fibrotic band replacing the absent muscle tissue. Neck range of motion was markedly decreased. The patient underwent a trial of muscle relaxants and intensive physical therapy with no significant improvement. Surgical release of the residual fibrotic band was performed, and the left deviation of the neck was reduced from 25 degrees preoperatively to 5 degrees postoperatively. With surgical release and intensive postoperative physical therapy, the patient regained full motion and strength of the cervical spine musculature.

  19. Complex rupture during the 12 January 2010 Haiti earthquake

    NASA Astrophysics Data System (ADS)

    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.

    2010-11-01

    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 Enriquillo-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 Enriquillo-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 Enriquillo-Plantain Garden fault zone, as occurred in inferred Holocene and probable historic events. We suggest that the geological signature of this earthquake-broad warping and coastal deformation rather than surface rupture along the main fault zone-will not be easily recognized by standard palaeoseismic studies. We conclude that similarly complex earthquakes in tectonic environments that accommodate both translation and convergence-such as the San Andreas fault through the Transverse Ranges of California-may be missing from the prehistoric earthquake record.

  20. Complex rupture during the 12 January 2010 Haiti earthquake

    USGS Publications Warehouse

    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

    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.

  1. Achilles tendon rupture rehabilitation

    PubMed Central

    Kearney, R. S.; Parsons, N.; Underwood, M.; Costa, M. L.

    2015-01-01

    Objectives The evidence base to inform the management of Achilles tendon rupture is sparse. The objectives of this research were to establish what current practice is in the United Kingdom and explore clinicians’ views on proposed further research in this area. This study was registered with the ISRCTN (ISRCTN68273773) as part of a larger programme of research. Methods We report an online survey of current practice in the United Kingdom, approved by the British Orthopaedic Foot and Ankle Society and completed by 181 of its members. A total of ten of these respondents were invited for a subsequent one-to-one interview to explore clinician views on proposed further research in this area. Results The survey showed wide variations in practice, with patients being managed in plaster cast alone (13%), plaster cast followed by orthoses management (68%), and orthoses alone (19%). Within these categories, further variation existed regarding the individual rehabilitation facets, such as the length of time worn, the foot position within them and weight-bearing status. The subsequent interviews reflected this clinical uncertainty and the pressing need for definitive research. Conclusions The gap in evidence in this area has resulted in practice in the United Kingdom becoming varied and based on individual opinion. Future high-quality randomised trials on this subject are supported by the clinical community. Cite this article: Bone Joint Res 2015;4:65–9 PMID:25868938

  2. Blood vessel rupture by cavitation

    PubMed Central

    Chen, Hong; Brayman, Andrew A.; Bailey, Michael R.

    2011-01-01

    Cavitation is thought to be one mechanism for vessel rupture during shock wave lithotripsy treatment. However, just how cavitation induces vessel rupture remains unknown. In this work, a high-speed photomicrography system was set up to directly observe the dynamics of bubbles inside blood vessels in ex vivo rat mesenteries. Vascular rupture correlating to observed bubble dynamics were examined by imaging bubble extravasation and dye leakage. The high-speed images show that bubble expansion can cause vessel distention, and bubble collapse can lead to vessel invagination. Liquid jets were also observed to form. Our results suggest that all three mechanisms, vessel distention, invagination and liquid jets, can contribute to vessel rupture. PMID:20680255

  3. Transverse Ising model with multi-impurity

    NASA Astrophysics Data System (ADS)

    Huang, Xuchu; Yang, Zhihua

    2015-05-01

    We study the transverse Ising spin model with spin-1 impurities under the exact solution. We develop a universal method to deal with the multi-impurity problem by introducing a displacement quantity in the wave function and get a recursive formula to simplify the calculation of the partition function. This allows us to rigorously determine the impurity effects for a specific distribution of impurity in the thermodynamic limit. The low temperature behaviors are governed by the interplay between host and impurity excitations, and the quantum critical fluctuations around the critical point of the transverse Ising model are tuned by the transverse field and the concentration of impurity. However the impurity effects are limited, which depends on the host-impurity exchange interaction and the coupling strength of impurities.

  4. The ruptured PIP breast implant.

    PubMed

    Helyar, V; Burke, C; McWilliams, S

    2013-08-01

    Public concern erupted about the safety of Poly Implant Prothèse (PIP) breast implants when it was revealed in 2011 that they contained an inferior, unlicensed industrial-grade silicone associated with a high rate of rupture. There followed national guidance for UK clinicians, which led to a considerable increase in referrals of asymptomatic women for breast implant assessment. In this review we discuss possible approaches to screening the PIP cohort and the salient characteristics of a ruptured implant. PMID:23622796

  5. Transverse spin and transverse momentum in scattering of plane waves

    NASA Astrophysics Data System (ADS)

    Saha, Sudipta; Singh, Ankit K.; Ray, Subir K.; Banerjee, Ayan; Gupta, Subhasish Dutta; Ghosh, Nirmalya

    2016-10-01

    We study the near field to the far field evolution of spin angular momentum (SAM) density and the Poynting vector of the scattered waves from spherical scatterers. The results show that at the near field, the SAM density and the Poynting vector are dominated by their transverse components. While the former (transverse SAM) is independent of the helicity of the incident circular polarization state, the latter (transverse Poynting vector) depends upon the polarization state. It is further demonstrated that the magnitudes and the spatial extent of the transverse SAM and the transverse momentum components can be controllably enhanced by exploiting the interference of the transverse electric and transverse magnetic scattering modes.

  6. Strength of Multiple Parallel Biological Bonds

    SciTech Connect

    Sulchek, T A; Friddle, R W; Noy, A

    2005-12-07

    Multivalent interactions play a critical role in a variety of biological processes on both molecular and cellular levels. We have used molecular force spectroscopy to investigate the strength of multiple parallel peptide-antibody bonds using a system that allowed us to determine the rupture forces and the number of ruptured bonds independently. In our experiments the interacting molecules were attached to the surfaces of the probe and sample of the atomic force microscope with flexible polymer tethers, and unique mechanical signature of the tethers determined the number of ruptured bonds. We show that the rupture forces increase with the number of interacting molecules and that the measured forces obey the predictions of a Markovian model for the strength of multiple parallel bonds. We also discuss the implications of our results to the interpretation of force spectroscopy measurements in multiple bond systems.

  7. Bladder rupture associated with uterine rupture at delivery.

    PubMed

    Yang, Bo

    2011-05-01

    This paper seeks to study the clinical presentation and emergency treatment of bladder rupture associated with uterine rupture at delivery. From June to December 2009, three cases of rupture of the uterus involving maternal bladder during labor at Revolutionary Hospital at Hodeidah, Yemen were reviewed. Intraoperatively, it appeared that the posterior wall of the bladder and the anterior wall of the uterus had ruptured; the laceration of the posterior bladder wall was closed in two layers. Of the patients who underwent the operations, one patient developed vesicovaginal fistula, which was repaired vaginally after 6 months, and the patient had a successful outcome. The others got uneventful recovery and there was no vesicovaginal fistula or hydronephrosis during follow-up. Uterine rupture and associated injury to the maternal bladder was rarely reported. It would be life threatening or would lead to long-term complications. Both urologists and obstetrician should keep bladder injuries in mind, as serious outcomes might occur during labor. Surgical treatment could be the preferred approach for this situation.

  8. Transverse colon conduit diversion

    SciTech Connect

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

    1986-05-01

    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.

  9. Nondiffracting transversally polarized beam.

    PubMed

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

    2011-09-01

    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 (∼4.84λ) 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

  10. Low stress drop earthquakes in the rupture zone of the 1992 Nicaragua tsunami earthquake

    NASA Astrophysics Data System (ADS)

    Bilek, Susan L.; Rotman, Holly M. M.; Phillips, W. Scott

    2016-10-01

    Tsunami earthquakes, events that generate larger than expected tsunami and are deficient in high-frequency seismic radiation, are rare but hazardous to coastal populations. One model for these events is shallow rupture through low-strength materials. We calculate seismic moment, corner frequency, and stress drop for 216 earthquakes (2.1 < Mw < 4.7, November 2005 to June 2006) within and external to the 1992 Nicaragua tsunami earthquake rupture zone to test the hypothesis that differences in fault zone properties defined the limits of the 1992 tsunami rupture zone and continue to produce spatial variations in earthquake source properties. Mean stress drop of events within the rupture area is 1.2 MPa, and 5.5 MPa for events just outside of the rupture zone, with similar magnitude earthquakes in each group. Our results demonstrate different source parameter characteristics for microseismicity in the region of a past tsunami earthquake.

  11. Acute medial elbow ruptures.

    PubMed

    Norwood, L A; Shook, J A; Andrews, J R

    1981-01-01

    Disruption of the ulnar collateral ligament, flexor muscles, and anterior elbow capsule may result from valgus vector forces and subsequently cause difficulty in throwing, pulling, pushing and catching. Complete medial elbow tears were diagnosed acutely in four elbows by abduction stress tests at 15 degrees of flexion. Three elbows had associated ulnar nerve compression. We repaired torn medial structures by direct suture without ligamentous reconstruction. We also decompressed ulnar nerves and performed one anterior transposition. Full range of motion, strength, and return to previous functional level was attained without infection, neurovascular compression, or myositis ossificans.

  12. Creep-rupture tests of internally pressurized Inconel 702 tubes

    NASA Technical Reports Server (NTRS)

    Gumto, K. H.

    1973-01-01

    Seamless Inconel 702 tubes with 0.375-in. outside diameter and 0.025-in. wall thickness were tested to failure at temperatures from 1390 to 1575 F and internal helium pressures from 700 to 1800 psi. Lifetimes ranged from 29 to 1561 hr. The creep-rupture strength of the tubes was about 70 percent lower than that of sheet specimens. Larson-Miller correlations and photomicrographs of some specimens are presented.

  13. Transverse Spin at RHIC

    NASA Astrophysics Data System (ADS)

    Wang, Xiaorong

    2016-03-01

    In recent years, there has been exciting development in both experimental and theoretical studies of transverse spin asymmetries in polarized p+p and and DIS collisions. As a unique polarized proton-proton collider, Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) provides a unique opportunity to investigate the novel physics mechanisms that cause the large single spin asymmetry at the forward rapidity. Both PHENIX and STAR experiments have been studying the transverse spin asymmetries with a variety of final state particles in different kinematic regimes since 2006. Especially, recent theoretical development on scattering a polarized probe on the saturated nuclear may provide a unique way to probe the gluon and quark TMDs. RHIC successfully ran polarized p+Au collisions in 2015. We will expect to have new results from polarized d+Au to compare with existing results from p+p collision to extend our understanding of QCD. Further more, In 2015, PHENIX installed MPC-ex calorimeter at very forward region to measure direct photon AN and STAR installed Roman Pots to study the diffractive events in polarized p+p and p+Au collisions. The recent results on transverse polarized p+p and p+Au collisions from both PHENIX and STAR experiments will be presented in this talk. I will also briefly discuss the possibility for the transverse Spin program at future experiments sPHENIX and forward sPHENIX at RHIC. Supported by US Department of Energy and RIKEN Brookhaven Research Center.

  14. Coupling a geodynamic seismic cycling model to rupture dynamic simulations

    NASA Astrophysics Data System (ADS)

    Gabriel, Alice; van Dinther, Ylona

    2014-05-01

    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

  15. Predicted Rupture Force of a Single Molecular Bond Becomes Rate Independent at Ultralow Loading Rates

    NASA Astrophysics Data System (ADS)

    Li, Dechang; Ji, Baohua

    2014-02-01

    We present for the first time a theoretical model of studying the saturation of the rupture force of a single molecular bond that causes the rupture force to be rate independent under an ultralow loading rate. This saturation will obviously bring challenges to understanding the rupture behavior of the molecular bond using conventional methods. This intriguing feature implies that the molecular bond has a nonzero strength at a vanishing loading rate. We find that the saturation behavior is caused by bond rebinding when the loading rate is lower than a limiting value depending on the loading stiffness.

  16. Reconstruction of chronic patellar tendon rupture with contralateral BTB autograft: a case report.

    PubMed

    Milankov, Miroslav Z; Miljkovic, Natasa; Stankovic, Milan

    2007-12-01

    Chronic patellar tendon rupture is a rare disabling injury that is technically difficult to repair. Many different surgical methods have been reported for the reconstruction of chronic patellar tendon ruptures. We are reporting the use of contralateral bone-tendon-bone (BTB) autograft for chronic patellar tendon rupture reconstruction followed by double-wire loop reinforcement and without postoperative immobilization. One year after the operation, our patient had full knee extension and up to 130 degrees of flexion. He had good quadriceps strength, and isokinetic muscle testing showed no deficit comparing to his right leg. Patient returned to playing basketball in his spare time, without having any limitation.

  17. Self-Rupturing Hermetic Valve

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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

  18. Spontaneous rupture of the ureter.

    PubMed

    Eken, Alper; Akbas, Tugana; Arpaci, Taner

    2015-02-01

    Spontaneous rupture of the ureter is a very rare condition and usually results from ureteral obstruction by a calculus. Only theoretical mechanisms have been proposed and no possible explanation has yet been reported in the literature. Intravenous contrast-enhanced computed tomography is the most informative study with high sensitivity. Treatment should be individualised, and depends on the state of the patient. Minimally invasive endourological procedures with double-J catheter placement and percutaneous drainage offer excellent results. Conservative management with analgesics and antibiotic coverage may be an alternative to surgery. Herein, we present a case of spontaneous rupture of the proximal ureter with no evidence of an underlying pathological condition.

  19. Enzymatically triggered rupture of polymersomes.

    PubMed

    Jang, Woo-Sik; Park, Seung Chul; Reed, Ellen H; Dooley, Kevin P; Wheeler, Samuel F; Lee, Daeyeon; Hammer, Daniel A

    2016-01-28

    Polymersomes are robust vesicles made from amphiphilic block co-polymers. Large populations of uniform giant polymersomes with defined, entrapped species can be made by templating of double-emulsions using microfluidics. In the present study, a series of two enzymatic reactions, one inside and the other outside of the polymersome, were designed to induce rupture of polymersomes. We measured how the kinetics of rupture were affected by altering enzyme concentration. These results suggest that protocells with entrapped enzymes can be engineered to secrete contents on cue.

  20. Insights into rupture processes of a laboratory-earthquake in dry and lubricated faults

    NASA Astrophysics Data System (ADS)

    Bayart, Elsa; Svetlizky, Ilya; Fineberg, Jay

    2016-04-01

    Our understanding of the dynamics of earthquakes requires us to understand the mechanisms of transition from static to sliding friction. The weakening of a fault is mediated by the propagation of rapid interfacial ruptures (earthquakes) that detach the solid contacts forming the frictional interface. By measuring the real contact area and strain fields near rough frictional interfaces, we have shown that these ruptures correspond to true shear cracks [1]. In particular, dynamic ruptures may spontaneously arrest at various locations along the interface. We show that a fracture-mechanics-based criterion can predict the location of the rupture arrest [2]. These results shed light on the selection of an earthquake's magnitude and arrest. Another interesting question is how interstitial fluids act to weaken a fault. By performing stick-slip experiments where the contacting surfaces are covered by a thin lubricating layer, we show that the established framework of fracture mechanics can also describe the measured strain fields when rupture of the interface takes place. A surprising result is that, although reducing the frictional strength of the interface (friction coefficient), lubricants actually significantly increase the fracture energy (amount of dissipated energy) during rupture. Thus surface lubrication, while strongly reducing the residual stresses in the wake of rupture propagation, actually toughens the contacting surfaces. [1] Svetlizky, I. & Fineberg, J. Classical shear cracks drive the onset of dry frictional motion. Nature 509, 205-208 (2014). [2] Bayart, E., Svetlizky, I. & Fineberg, J. Fracture mechanics determine the lengths of interface ruptures that mediate frictional motion. Nature Physics (2015).

  1. Partonic Transverse Momentum Distributions

    SciTech Connect

    Rossi, Patrizia

    2010-08-04

    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.

  2. Transverse testicular ectopia.

    PubMed

    Yıldız, Abdullah; Yiğiter, Murat; Oral, Akgün; Bakan, Vedat

    2014-02-01

    Described herein are six cases of transverse testicular ectopia. All patients who underwent orchidopexy at the one pediatric surgical unit between October 2001 and January 2008 were evaluated. The medical records of all patients diagnosed with transverse testicular ectopia were evaluated retrospectively. Five patients (84%) were admitted with a symptomatic right inguinal hernia and empty scrotum on the left side. Only one child (16%) had left-sided hernia and right non-palpable testis (age ranged from 1 month to 3 years). Four patients (66%) were diagnosed in the operating theatre and the last two (33%) on inguinal ultrasound preoperatively. Magnetic resonance imaging was also performed in the last patient. Herniorrhaphy with fixation of the ectopic gonad to the opposite hemiscrotum through a transseptal incision was performed in all patients. Postoperative complications were not observed. PMID:24548194

  3. Spontaneous rupture of spleen in falciparum malaria.

    PubMed

    Vidyashankar, C; Basu, Arup; Kulkarni, A R; Choudhury, R K

    2003-01-01

    Spontaneous rupture of spleen is an extremely rare complication of falciparum malaria. We report a 3 1/2-year-old girl with splenic rupture who was managed successfully with splenectomy and antimalarials.

  4. Spontaneous bilateral quadriceps tendon rupture.

    PubMed

    Vigneswaran, N; Lee, K; Yegappan, M

    2007-11-01

    Spontaneous bilateral quadriceps tendon ruptures are uncommon. We present a 30-year-old man with end-stage renal failure, who sustained this injury, and subsequently had surgical repair of both tendons on separate occasions. He has since regained full range of movement of both knees.

  5. Dissipative Landau-Zener quantum dynamics with transversal and longitudinal noise

    NASA Astrophysics Data System (ADS)

    Javanbakht, S.; Nalbach, P.; Thorwart, M.

    2015-05-01

    We determine the Landau-Zener transition probability in a dissipative environment including both longitudinal as well as transversal quantum-mechanical noise originating from a single noise source. For this, we use the numerically exact quasiadiabatic path integral, as well as the approximative nonequilibrium Bloch equations. We find that transversal quantum noise in general influences the Landau-Zener probability much more strongly than longitudinal quantum noise does at a given temperature and system-bath coupling strength. In other words, transversal noise contributions become important even when the coupling strength of transversal noise is smaller than that of longitudinal noise. We furthermore reveal that transversal noise renormalizes the tunnel coupling independent of temperature. Finally, we show that the effect of mixed longitudinal and transversal noise originating from a single bath cannot be obtained from an incoherent sum of purely longitudinal and purely transversal noise.

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    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.

  7. Quadriceps Tendon Rupture due to Postepileptic Convulsion

    PubMed Central

    Erkut, Adem; Guvercin, Yilmaz; Sahin, Rifat; Keskin, Davut

    2014-01-01

    We present a case of quadriceps tendon (QT) rupture. QT ruptures can occur in all ages. The cause is mostly traumatic in origin. Spontaneous ruptures that are thought to result from predisposing conditions are rare. Post-convulsion QT ruptures lacking traumas in their history can be overlooked in clinical examinations. This should be born in mind by the attending physician, as early diagnosis and treatment of the condition can lead to satisfactory outcomes. PMID:24944977

  8. Spontaneous perforation of solitary ulcer of transverse colon.

    PubMed

    Galanis, Ioannis; Dragoumis, Dimitrios; Kalogirou, Thomas; Lakis, Sotiris; Kotakidou, Rodi; Atmatzidis, Konstantinos

    2010-01-01

    Spontaneous ruptures of the colon and rectum are extremely uncommon clinical entities and always require laparotomy. A 44-year-old female was admitted with a 12-hour history of severe abdominal pain periumbilically and at the right hypochondrium. The patient was immediately transferred to the department of surgery for close surgical observation. Computed tomography (CT) of the entire abdomen performed just before the operation demonstrated thickening of the wall of the ascending colon with pericolic fat stranding. Surgery revealed a perforation at the antimesenteric wall of the transverse colon and segmental colectomy of the transverse colon was performed. The histological evaluation demonstrated a perforated solitary ulcer of the transverse colon. There are only few known etiologic factors concerning spontaneous ruptures of the colon and rectum and usually none of these causative factors can easily be recognised. Their clinical appearance is most of the times acute abdomen and, despite the use of all appropriate diagnostic methods, the diagnosis is usually set postoperatively. PMID:20090246

  9. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  10. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  11. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  12. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  13. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  14. Effect of Electron Beam Irradiation on Tensile Strength of Polypropylene

    NASA Astrophysics Data System (ADS)

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

    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.

  15. Dynamic Rupture Segmentation Along The Nankai Trough, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Hok, S.; Fukuyama, E.; Hashimoto, C.

    2010-12-01

    ). Inside the barrier, the fracture energy changes in regional scale, via a change of the critical slip distance scaling. The strength remains uniform along the interface. Asperities are produced by the initial stress distribution inferred from slip deficit. Using this model setting, we computed a few different spontaneous rupture scenarios, by changing only the location of rupture initiation. Remarkably, we could reproduce the segmentation of the rupture, as observed during the 1940’s sequence, provided that the rupture initiates close to the Kii peninsula barrier area. However, if the rupture initiate far from the Kii peninsula, close to Tokai or west of Muroto cape for instance, the rupture is more likely to break the full plate interface in a single rupture event, consistently with what has been observed in the past. The rupture segmentation appears to be a consequence of the friction properties off-Kii Peninsula, as well as the rupture initiation position. This work provides a reliable way to enlighten the conditional segmentation process, as a consequence of the earthquake dynamic rupture.

  16. Extracellular Matrix Dynamics and Fetal Membrane Rupture

    PubMed Central

    Strauss,, Jerome F.

    2013-01-01

    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

  17. High-strength iron aluminide alloys

    SciTech Connect

    McKamey, C.G.; Marrero-Santos, Y.; Maziasz, P.J.

    1995-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile density due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications, despite their excellent corrosion properties. Improvements in room temperature tensile ductility have been realized mainly through alloying effects, changes in thermomechanical processing to control microstructure, and by control of the specimen`s surface condition. Ductilities of 10-20% and tensile yield strengths as high as 500 MPa have been reported. In terms of creep-rupture strength, small additions of Mo, Nb, and Zr have produced significant improvements, but at the expense of weldability and room-temperature tensile ductility. Recently an alloy containing these additions, designated FA-180, was shown to exhibit a creep-rupture life of over 2000 h after a heat treatment of 1 h at 1150{degrees}C. This study presents the results of creep-rupture tests at various test temperatures and stresses and discusses the results as part of our effort to understand the strengthening mechanisms involved with heat treatment at 1150{degrees}C.

  18. Neutron Transversity at Jefferson Lab

    SciTech Connect

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

    2005-09-07

    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.

  19. Characteristics of transverse waves in chromospheric mottles

    SciTech Connect

    Kuridze, D.; Mathioudakis, M.; Jess, D. B.; Keenan, F. P.; Verth, G.; Erdélyi, R.; Morton, R. J.; Christian, D. J.

    2013-12-10

    Using data obtained by the high temporal and spatial resolution Rapid Oscillations in the Solar Atmosphere instrument on the Dunn Solar Telescope, we investigate at an unprecedented level of detail transverse oscillations in chromospheric fine structures near the solar disk center. The oscillations are interpreted in terms of propagating and standing magnetohydrodynamic kink waves. Wave characteristics including the maximum transverse velocity amplitude and the phase speed are measured as a function of distance along the structure's length. Solar magnetoseismology is applied to these measured parameters to obtain diagnostic information on key plasma parameters (e.g., magnetic field, density, temperature, flow speed) of these localized waveguides. The magnetic field strength of the mottle along the ∼2 Mm length is found to decrease by a factor of 12, while the local plasma density scale height is ∼280 ± 80 km.

  20. Identifying risk factors for uterine rupture.

    PubMed

    Smith, Jennifer G; Mertz, Heather L; Merrill, David C

    2008-03-01

    Uterine rupture, whether in the setting of a prior uterine incision or in an unscarred uterus, is an obstetric emergency with potentially catastrophic consequences for both mother and child. Numerous studies have been published regarding various risk factors associated with uterine rupture. Despite the mounting data regarding both antepartum and intrapartum factors, it currently is impossible to predict in whom a uterine rupture will occur. This article reviews the data regarding these antepartum and intrapartum predictors for uterine rupture. The author hopes that the information presented in this article will help clinicians assess an individual's risk for uterine rupture.

  1. Transverse field focused system

    DOEpatents

    Anderson, Oscar A.

    1986-01-01

    A transverse field focused (TFF) system for transport or acceleration of an intense sheet beam of negative ions in which a serial arrangement of a plurality of pairs of concentric cylindrical-arc electrodes is provided. Acceleration of the sheet beam can be achieved by progressively increasing the mean electrode voltage of successive electrode pairs. Because the beam is curved by the electrodes, the system can be designed to transport the beam through a maze passage which is baffled to prevent line of sight therethrough. Edge containment of the beam can be achieved by shaping the side edges of the electrodes to produce an electric force vector directed inwardly from the electrode edges.

  2. [Quadriceps and patellar tendon ruptures].

    PubMed

    Grim, C; Lorbach, O; Engelhardt, M

    2010-12-01

    Ruptures of the quadriceps or patellar tendon are uncommon but extremely relevant injuries. Early diagnosis and surgical treatment with a stable suture construction are mandatory for a good postoperative clinical outcome. The standard methods of repair for quadriceps and patellar tendon injuries include the placement of suture loops through transpatellar tunnels. Reinforcement with either a wire cerclage or a PDS cord is used in patellar tendon repair. The PDS cord can also be applied as augmentation in quadriceps tendon repair. In secondary patellar tendon repair an autologous semitendinosus graft can be used. For chronic quadriceps tendon defects a V-shaped tendon flap with a distal footing is recommended. The different methods of repair should lead to early functional postoperative treatment. The clinical outcome after surgical treatment of patellar and quadriceps tendon ruptures is mainly good.

  3. [Two cases of testicular rupture].

    PubMed

    Tsujino, S; Hirata, T; Shimizu, H; Ito, T; Shiozawa, H; Koshiba, K

    1989-06-01

    Two cases of testicular rupture are presented and 119 cases in Japanese literature are reviewed. A 29-year-old man and a 32-year-old man were admitted to our hospital with the complaint of gradually increasing pains and swelling on the right testicle. Four days and three days before admission they experienced trauma during athletic activities. The diagnosis was established preoperatively by means of ultrasonography in the first one, but not in the other. The necrotic tissue of 1/3-1/2 of testis was removed and tunica albuginea was repaired in both cases. Of 119 cases of testicular rupture in Japanese literature a peak occurs in the 2nd decade and during contact sports. The ultrasonography is an effective diagnostic modality. The rate of orchiectomy has been decreasing. The function of the affected testis is hard to evaluate.

  4. Transverse Compression of Tendons.

    PubMed

    Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon. PMID:26833218

  5. Transverse Compression of Tendons.

    PubMed

    Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon.

  6. Rupture of vertical soap films

    NASA Astrophysics Data System (ADS)

    Rio, Emmanuelle

    2014-11-01

    Soap films are ephemeral and fragile objects. They tend to thin under gravity, which gives rise to the fascinating variations of colors at their interfaces but leads systematically to rupture. Even a child can create, manipulate and admire soap films and bubbles. Nevertheless, the reason why it suddenly bursts remains a mystery although the soap chosen to stabilize the film as well as the humidity of the air seem very important. One difficulty to study the rupture of vertical soap films is to control the initial solution. To avoid this problem we choose to study the rupture during the generation of the film at a controlled velocity. We have built an experiment, in which we measure the maximum length of the film together with its lifetime. The generation of the film is due to the presence of a gradient of surface concentration of surfactants at the liquid/air interface. This leads to a Marangoni force directed toward the top of the film. The film is expected to burst only when its weight is not balanced anymore by this force. We will show that this leads to the surprising result that the thicker films have shorter lifetimes than the thinner ones. It is thus the ability of the interface to sustain a surface concentration gradient of surfactants which controls its stability.

  7. Molecular dynamics of interface rupture

    NASA Technical Reports Server (NTRS)

    Koplik, Joel; Banavar, Jayanth R.

    1993-01-01

    Several situations have been studied in which a fluid-vapor or fluid-fluid interface ruptures, using molecular dynamics simulations of 3000 to 20,000 Lennard-Jones molecules in three dimensions. The cases studied are the Rayleigh instability of a liquid thread, the burst of a liquid drop immersed in a second liquid undergoing shear, and the rupture of a liquid sheet in an extensional flow. The late stages of the rupture process involve the gradual withdrawal of molecules from a thinning neck, or the appearance and growth of holes in a sheet. In all cases, it is found that despite the small size of the systems studied, tens of angstroms, the dynamics is in at least qualitative accord with the behavior expected from continuum calculations, and in some cases the agreement is to within tens of percent. Remarkably, this agreement occurs even though the Eulerian velocity and stress fields are essentially unmeasurable - dominated by thermal noise. The limitations and prospects for such molecular simulation techniques are assessed.

  8. Splenic rupture following routine colonoscopy.

    PubMed

    Rasul, Tabraze; Leung, Edmund; McArdle, Kirsten; Pathak, Rajiv; Dalmia, Sanjay

    2010-10-01

    Splenic rupture is a life-threatening condition characterized by internal hemorrhage, often difficult to diagnose. Colonoscopy is a gold standard routine diagnostic test to investigate patients with gastrointestinal symptoms as well as to those on the screening program for colorectal cancer. Splenic injury is seldomly discussed during consent for colonoscopy, as opposed to colonic perforation, as its prevalence accounts for less than 0.1%. A 66-year-old Caucasian woman with no history of collagen disorder was electively admitted for routine colonoscopy for surveillance of adenoma. She was admitted following the procedure for re-dosing of warfarin, which was stopped prior to the colonoscopy. The patient was found collapsed on the ward the following day with clinical shock and anemia. Computed tomography demonstrated grade 4 splenic rupture. Immediate blood transfusion and splenectomy was required. Splenic rupture following routine colonoscopy is extremely rare. Awareness of it on this occasion saved the patient's life. Despite it being a rare association, the seriousness warrants inclusion in all information leaflets concerning colonoscopy and during its consent.

  9. Computational evaluation of aortic aneurysm rupture risk: what have we learned so far?

    PubMed

    Georgakarakos, Efstratios; Ioannou, Christos V; Papaharilaou, Yannis; Kostas, Theodoros; Katsamouris, Asterios N

    2011-04-01

    In current clinical practice, aneurysm diameter is one of the primary criteria used to decide when to treat a patient with an abdominal aortic aneurysm (AAA). It has been shown that simple association of aneurysm diameter with the probability of rupture is not sufficient, and other parameters may also play a role in causing or predisposing to AAA rupture. Peak wall stress (PWS), intraluminal thrombus (ILT), and AAA wall mechanics are the factors most implicated with rupture risk and have been studied by computational risk evaluation techniques. The objective of this review is to examine these factors that have been found to influence AAA rupture. The prediction rate of rupture among computational models depends on the level of model complexity and the predictive value of the biomechanical parameters used to assess risk, such as PWS, distribution of ILT, wall strength, and the site of rupture. There is a need for simpler geometric analogues, including geometric parameters (e.g., lumen tortuosity and neck length and angulation) that correlate well with PWS, conjugated with clinical risk factors for constructing rupture risk predictive models. Such models should be supported by novel imaging techniques to provide the required patient-specific data and validated through large, prospective clinical trials. PMID:21521062

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

    SciTech Connect

    Cloos, M. )

    1992-07-01

    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.

  11. Flow Dynamics of Aneurysm Growth and Rupture: Challenges for the Development of Computational Flow Dynamics as a Diagnostic Tool to Detect Rupture-Prone Aneurysms.

    PubMed

    Frösen, Juhana

    2016-01-01

    Saccular intracranial aneurysm (sIA) is a relatively common disease that can potentially cause a devastating, life-threatening intracranial hemorrhage. Many sIAs never rupture and thus do not necessitate interventions, making the detection of rupture-prone sIAs a very relevant clinical problem. Moreover, because currently available methods to prevent sIA rupture have significant risks of morbidity and mortality, diagnostic tools that can predict imminent rupture and help plan proper timing of prophylactic interventions, can improve patient care. Hemorrhage from an sIA occurs when hemodynamic stress exceeds sIA wall strength. Computational fluid dynamics (CFD) is a tool with which the hemodynamic stress to which the sIA wall is exposed can be determined non-invasively. Studies using CFD in sIAs have demonstrated associations of wall shear stress (WSS) with aneurysm growth, fragile sIA wall, and sIA rupture; these studies show the potential of CFD as a diagnostic tool. This review discusses the limitations of CFD and of the studies performed, and what needs to be done in order to develop CFD into a useful diagnostic tool to determine aneurysm-specific rupture risk. PMID:27637634

  12. Ground motion hazard from supershear rupture

    USGS Publications Warehouse

    Andrews, D.J.

    2010-01-01

    An idealized rupture, propagating smoothly near a terminal rupture velocity, radiates energy that is focused into a beam. For rupture velocity less than the S-wave speed, radiated energy is concentrated in a beam of intense fault-normal velocity near the projection of the rupture trace. Although confined to a narrow range of azimuths, this beam diverges and attenuates. For rupture velocity greater than the S-wave speed, radiated energy is concentrated in Mach waves forming a pair of beams propagating obliquely away from the fault. These beams do not attenuate until diffraction becomes effective at large distance. Events with supershear and sub-Rayleigh rupture velocity are compared in 2D plane-strain calculations with equal stress drop, fracture energy, and rupture length; only static friction is changed to determine the rupture velocity. Peak velocity in the sub-Rayleigh case near the termination of rupture is larger than peak velocity in the Mach wave in the supershear case. The occurrence of supershear rupture propagation reduces the most intense peak ground velocity near the fault, but it increases peak velocity within a beam at greater distances. ?? 2010.

  13. Environmental Durability and Stress Rupture of EBC/CMCs

    NASA Technical Reports Server (NTRS)

    Appleby, Matthew; Morscher, Gregory N.; Zhu, Dongming

    2012-01-01

    This research focuses on the strength and creep performance of SiC fiber-reinforced SiC ceramic matrix composite (CMC) environmental barrier coating (EBC) systems under complex simulated engine environments. Tensile-strength and stress-rupture testing was conducted to illustrate the material properties under isothermal and thermal gradient conditions. To determine material durability, further testing was conducted under exposure to thermal cycling, thermal gradients and simulated combustion environments. Emphasis is placed on experimental techniques as well as implementation of non-destructive evaluation, including modal acoustic emission and electrical resistivity monitoring, to characterize strength degradation and damage mechanisms. Currently, little is known about the behavior of EBC-CMCs under these conditions; consequently, this work will prove invaluable in the development of structural components for use in high temperature applications.

  14. Alliance ruptures and rupture resolution in cognitive-behavior therapy: a preliminary task analysis.

    PubMed

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

    2008-11-01

    An initial ideal, rational model of alliance rupture and rupture resolution provided by cognitive-behavioral 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 and what they actually do and suggested that the rational model should be expanded to emphasize client validation and empowerment. Therapists' ability to attend to ruptures emerged as an important clinical skill.

  15. Transverse Wobbling in 135Pr

    NASA Astrophysics Data System (ADS)

    Matta, J. T.; Garg, U.; Li, W.; Frauendorf, S.; Ayangeakaa, A. D.; Patel, D.; Schlax, K. W.; Palit, R.; Saha, S.; Sethi, J.; Trivedi, T.; Ghugre, S. S.; Raut, R.; Sinha, A. K.; Janssens, R. V. F.; Zhu, S.; Carpenter, M. P.; Lauritsen, T.; Seweryniak, D.; Chiara, C. J.; Kondev, F. G.; Hartley, D. J.; Petrache, C. M.; Mukhopadhyay, S.; Lakshmi, D. Vijaya; Raju, M. Kumar; Madhusudhana Rao, P. V.; Tandel, S. K.; Ray, S.; Dönau, F.

    2015-02-01

    A pair of transverse wobbling bands is observed in the nucleus 135Pr . The wobbling is characterized by Δ I =1 , E 2 transitions between the bands, and a decrease in the wobbling energy confirms its transverse nature. Additionally, a transition from transverse wobbling to a three-quasiparticle band comprised of strong magnetic dipole transitions is observed. These observations conform well to results from calculations with the tilted axis cranking model and the quasiparticle rotor model.

  16. Transverse Spin Effects at COMPASS

    SciTech Connect

    Wollny, H.

    2009-08-04

    The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering (SIDIS) is an important part of the COMPASS physics program. In the years 2002-2004 data was taken by scattering a 160 GeV/c muon beam off a transversely polarized deuteron target. In 2007, additional data was collected on a transversely polarized proton target. New preliminary results for the Collins and Sivers asymmetries from the analysis of the proton data are presented.

  17. Pediatric transverse myelitis.

    PubMed

    Absoud, Michael; Greenberg, Benjamin M; Lim, Ming; Lotze, Tim; Thomas, Terrence; Deiva, Kumaran

    2016-08-30

    Pediatric acute transverse myelitis (ATM) is an immune-mediated CNS disorder and contributes to 20% of children experiencing a first acquired demyelinating syndrome (ADS). ATM must be differentiated from other presentations of myelopathy and may be the first presentation of relapsing ADS such as neuromyelitis optica (NMO) or multiple sclerosis (MS). The tenets of the diagnostic criteria for ATM established by the Transverse Myelitis Consortium Working Group can generally be applied in children; however, a clear sensory level may not be evident in some. MRI lesions are often centrally located with high T2 signal intensity involving gray and neighboring white matter. Longitudinally extensive ATM occurs in the majority. Asymptomatic lesions on brain MRI are seen in more than one-third and predict MS or NMO. The role of antibodies such as myelin oligodendrocyte glycoprotein in monophasic and relapsing ATM and their significance in therapeutic approaches remain unclear. ATM is a potentially devastating condition with variable outcome and presents significant cumulative demands on health and social care resources. Children generally have a better outcome than adults, with one-half making a complete recovery by 2 years. There is need for standardization of clinical assessment and investigation protocols to enable international collaborative studies to delineate prognostic factors for disability and relapse. There are no robust controlled trials in children or adults to inform optimal treatment of ATM, with one study currently open to recruitment. This review provides an overview of current knowledge of clinical features, investigative workup, pathogenesis, and management of ATM and suggests future directions. PMID:27572861

  18. Multiple linear regression models to fit magnitude using rupture length, rupture width, rupture area, and surface displacement

    NASA Astrophysics Data System (ADS)

    Chu, A.; Zhuang, J.

    2015-12-01

    Wells and Coppersmith (1994) have used fault data to fit simple linear regression (SLR) models to explain linear relations between moment magnitude and logarithms of fault measurements such as rupture length, rupture width, rupture area and surface displacement. Our work extends their analyses to multiple linear regression (MLR) models by considering two or more predictors with updated data. Treating the quantitative variables (rupture length, rupture width, rupture area and surface displacement) as predictors to fit linear regression models on magnitude, we have discovered that the two-predictor model using rupture area and maximum displacement fits the best. The next best alternative predictors are surface length and rupture area. Neither slip type nor slip direction is a significant predictor by fitting of analysis of variance (ANOVA) and analysis of covariance (ANCOVA) models. Corrected Akaike information criterion (Burnham and Anderson, 2002) is used as a model assessment criterion. Comparisons between simple linear regression models of Wells and Coppersmith (1994) and our multiple linear regression models are presented. Our work is done using fault data from Wells and Coppersmith (1994) and new data from Ellswort (2000), Hanks and Bakun (2002, 2008), Shaw (2013), and Finite-Source Rupture Model Database (http://equake-rc.info/SRCMOD/, 2015).

  19. Histologic analysis of ruptured quadriceps tendons.

    PubMed

    Trobisch, Per David; Bauman, Matthias; Weise, Kuno; Stuby, Fabian; Hak, David J

    2010-01-01

    Quadriceps tendon ruptures are uncommon injuries. Degenerative changes in the tendon are felt to be an important precondition for rupture. We retrospectively reviewed 45 quadriceps tendon ruptures in 42 patients. Quadriceps tendon ruptures occurred most often in the sixth and seventh decade of life. Men were affected six times as often as women. A tissue sample from the rupture-zone was obtained in 22 cases and histologic analysis was performed. Degenerative changes were present in only 14 (64%) of the 22 samples. We observed an increasing ratio of degenerative to nondegenerative tendons with increasing patient age. Our data suggests that quadriceps tendon rupture, especially in younger patients, can occur in the absence of pathologic tendon degeneration.

  20. Early second trimester uterine scar rupture.

    PubMed

    Bharatnur, Sunanda; Hebbar, Shripad; Shyamala, G

    2013-12-10

    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.

  1. Complex rupture of the M6.3 2015 March 10 Bucaramanga earthquake: evidence of strong weakening process

    NASA Astrophysics Data System (ADS)

    Poli, P.; Prieto, G. A.; Yu, C. Q.; Florez, M.; Agurto-Detzel, H.; Mikesell, T. D.; Chen, G.; Dionicio, V.; Pedraza, P.

    2016-05-01

    We use seismic waves for a magnitude 6.3 intermediate-depth (160 km) earthquake in the Bucaramanga Nest, Colombia, to infer a complex rupture process with two distinct stages, characterized by different rupture velocities possibly controlled by the evolution of strength on the fault. Our integrated data processing permitted to precisely characterize the multistage rupture and the presence of a strong weakening event. The resulting seismic radiation is interpreted as resulting from an extreme weakening due to a cascading thermal shear runaway, with an initial inefficient radiation process followed by a fast and dynamic efficient rupture. Our results imply dynamic complexity of the seismic rupture deep inside the Earth, and may help to give some new insights about the physical mechanism of intermediate-depth earthquakes.

  2. Investigation of cryogenic rupture disc design

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    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.

  3. Mitochondrial swelling and incipient outer membrane rupture in preapoptotic and apoptotic cells.

    PubMed

    Sesso, A; Belizário, J E; Marques, M M; Higuchi, M L; Schumacher, R I; Colquhoun, A; Ito, E; Kawakami, J

    2012-10-01

    Outer mitochondrial membrane (OMM) rupture was first noted in isolated mitochondria in which the inner mitochondrial membrane (IMM) had lost its selective permeability. This phenomenon referred to as mitochondrial permeability transition (MPT) refers to a permeabilized inner membrane that originates a large swelling in the mitochondrial matrix, which distends the outer membrane until it ruptures. Here, we have expanded previous electron microscopic observations that in apoptotic cells, OMM rupture is not caused by a membrane stretching promoted by a markedly swollen matrix. It is shown that the widths of the ruptured regions of the OMM vary from 6 to 250 nm. Independent of the perforation size, herniation of the mitochondrial matrix appeared to have resulted in pushing the IMM through the perforation. A large, long focal herniation of the mitochondrial matrix, covered with the IMM, was associated with a rupture of the OMM that was as small as 6 nm. Contextually, the collapse of the selective permeability of the IMM may precede or follow the release of the mitochondrial proteins of the intermembrane space into the cytoplasm. When the MPT is a late event, exit of the intermembrane space proteins to the cytoplasm is unimpeded and occurs through channels that transverse the outer membrane, because so far, the inner membrane is impermeable. No channel within the outer membrane can expose to the cytoplasm a permeable inner membrane, because it would serve as a conduit for local herniation of the mitochondrial matrix.

  4. Acute Pectoralis Major Rupture Captured on Video.

    PubMed

    Ordas Bayon, Alejandro; Sandoval, Enrique; Valencia Mora, María

    2016-01-01

    Pectoralis major (PM) ruptures are uncommon injuries, although they are becoming more frequent. We report a case of a PM rupture in a young male who presented with axillar pain and absence of the anterior axillary fold after he perceived a snap while lifting 200 kg in the bench press. Diagnosis of PM rupture was suspected clinically and confirmed with imaging studies. The patient was treated surgically, reinserting the tendon to the humerus with suture anchors. One-year follow-up showed excellent results. The patient was recording his training on video, so we can observe in detail the most common mechanism of injury of PM rupture. PMID:27595030

  5. Spontaneous rupture of uterine leiomyoma during labour.

    PubMed

    Ramskill, Nikki; Hameed, Aisha; Beebeejaun, Yusuf

    2014-09-08

    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.

  6. Rupture dynamics in model polymer systems.

    PubMed

    Borah, Rupam; Debnath, Pallavi

    2016-05-11

    In this paper we explore the rupture dynamics of a model polymer system to capture the microscopic mechanism during relative motion of surfaces at the single polymer level. Our model is similar to the model for friction introduced by Filippov, Klafter, and Urbakh [Filippov et al., Phys. Rev. Lett., 2004, 92, 135503]; but with an important generalization to a flexible transducer (modelled as a bead spring polymer) which is attached to a fixed rigid planar substrate by interconnecting bonds (modelled as harmonic springs), and pulled by a constant force FT. Bonds are allowed to rupture stochastically. The model is simulated, and the results for a certain set of parameters exhibit a sequential rupture mechanism resulting in rupture fronts. A mean field formalism is developed to study these rupture fronts and the possible propagating solutions for the coupled bead and bond dynamics, where the coupling excludes an exact analytical treatment. Numerical solutions to mean field equations are obtained by standard numerical techniques, and they agree well with the simulation results which show sequential rupture. Within a travelling wave formalism based on the Tanh method, we show that the velocity of the rupture front can be obtained in closed form. The derived expression for the rupture front velocity gives good agreement with the stochastic and mean field results, when the rupture is sequential, while propagating solutions for bead and bond dynamics are shown to agree under certain conditions. PMID:27087684

  7. Spontaneous rupture of uterine leiomyoma during labour

    PubMed Central

    Ramskill, Nikki; Hameed, Aisha; Beebeejaun, Yusuf

    2014-01-01

    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

  8. Acute Pectoralis Major Rupture Captured on Video

    PubMed Central

    Valencia Mora, María

    2016-01-01

    Pectoralis major (PM) ruptures are uncommon injuries, although they are becoming more frequent. We report a case of a PM rupture in a young male who presented with axillar pain and absence of the anterior axillary fold after he perceived a snap while lifting 200 kg in the bench press. Diagnosis of PM rupture was suspected clinically and confirmed with imaging studies. The patient was treated surgically, reinserting the tendon to the humerus with suture anchors. One-year follow-up showed excellent results. The patient was recording his training on video, so we can observe in detail the most common mechanism of injury of PM rupture. PMID:27595030

  9. Creep-rupture tests of internally pressurized Rene 41 tubes

    NASA Technical Reports Server (NTRS)

    Gumto, K. H.; Weiss, B.

    1972-01-01

    Weld-drawn tubes of Rene 41 with 0.935 centimeter outside diameter and 0.064 centimeter wall thickness were tested to failure at temperatures from 1117 to 1233 K and internal helium pressures from 5.5 to 12.4 meganewtons per square meter. Lifetimes ranged from 5 to 2065 hours. The creep-rupture strength of the tubes was 50 percent lower than that of unwelded, thick sheet specimens, and 20 percent lower than that of unwelded, thin sheet specimens. Larson-Miller correlations and photomicrographs of some specimens are presented.

  10. General formulation of transverse hydrodynamics

    SciTech Connect

    Ryblewski, Radoslaw; Florkowski, Wojciech

    2008-06-15

    General formulation of hydrodynamics describing transversally thermalized matter created at the early stages of ultrarelativistic heavy-ion collisions is presented. Similarities and differences with the standard three-dimensionally thermalized relativistic hydrodynamics are discussed. The role of the conservation laws as well as the thermodynamic consistency of two-dimensional thermodynamic variables characterizing transversally thermalized matter is emphasized.

  11. Proximal humerus shaft fracture after pectoralis major tendon rupture repair.

    PubMed

    Silverstein, Jeff A; Goldberg, Ben; Wolin, Preston

    2011-06-01

    Surgical repair of a complete pectoralis major tendon rupture at the humeral insertion has superior results compared to nonoperative treatment. To our knowledge, a proximal humerus shaft fracture occurring at the site of the bone trough and cortical drill holes after a pectoralis major tendon rupture repair has not been reported in the literature.A 45-year-old man sustained an acute left pectoralis major tendon rupture at the humeral insertion while performing a bench press maneuver. He underwent acute surgical repair. Approximately 8 weeks postoperatively, the patient fell from a standing height and sustained a proximal humerus shaft fracture through the repair site at the bone trough. Three days after the fracture, the patient underwent open reduction and internal fixation of the proximal humerus shaft fracture and exploration of the pectoralis major tendon repair. The fracture was found to be at the level of the repair site, and the pectoralis major tendon was completely intact to the distal fragment. The fracture healed uneventfully, and the patient regained full motion and strength of his extremity with no limitations.Any type of surgical fixation that creates a hole in the humerus or decreases the cross-sectional area such as a bone trough creates a stress riser. Patients undergoing pectoralis tendon repair that involves violating the humerus with a bone trough or hole have a slight risk of postoperative humerus fracture, especially if sustaining an early traumatic event such as a fall. PMID:21667914

  12. Material Parameters for Creep Rupture of Austenitic Stainless Steel Foils

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    Creep rupture properties of austenitic stainless steel foil, 347SS, used in compact recuperators have been evaluated at 700 °C 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.

  13. Quadriceps and patellar tendon ruptures.

    PubMed

    Lee, Dennis; Stinner, Daniel; Mir, Hassan

    2013-10-01

    The diagnosis of quadriceps and patellar tendon ruptures requires a high index of suspicion and thorough history-taking to assess for medical comorbidities that may predispose patients to tendon degeneration. Radiographic assessment with plain films supplemented by ultrasound and magnetic resonance imaging when the work-up is equivocal further aids diagnosis; however, advanced imaging is often unnecessary in patients with functional extensor mechanism deficits. Acute repair is preferred, and transpatellar bone tunnels serve as the primary form of fixation when the tendon rupture occurs at the patellar insertion, with or without augmentation depending on surgeon preference. Chronic tears and disruptions following total knee arthroplasty are special cases requiring reconstructions with allograft, synthetic mesh, or autograft. Rehabilitation protocols generally allow immediate weight-bearing with the knee locked in extension and crutch support. Limited arc motion is started early with active flexion and passive extension and then advanced progressively, followed by full active range of motion and strengthening. Complications are few but include quadriceps atrophy, knee stiffness, and rerupture. Outcomes are excellent if repair is done acutely, with poorer outcomes associated with delayed repair.

  14. Breaking of a single asperity: Rupture process and seismic radiation

    NASA Astrophysics Data System (ADS)

    Das, S.; Kostrov, B. V.

    1983-05-01

    The problem of spontaneous shear rupture of a single circular asperity on an infinite fault plane is studied. Initially, the fault plane is broken everywhere except at a circular asperity. An applied displacement at infinity results in a stress concentration along the bounding edge of the asperity. The frictional stress on the broken part of the fault plane is taken to be a constant. Once a point on the asperity breaks, the stress there drops to the same value as on the `main' fault surface. The rupture is started by relaxing the shear stress at a point on the asperity edge and is then allowed to propagate spontaneously, using a critical stress level fracture criterion. The rupture process is calculated numerically. It is found that for asperities of constant strength, the rupture first propagates around the edge of the asperity and then inward, a phenomenon best described by the well-known term of classic military maneuver: `the double encircling pincer movement.' In the appendix, the expressions for the far-field seismic radiation due to the rupture of such an asperity are derived. It is shown that the nth Cartesian component of the far-field displacement at (x, t) for P, SV, and SH waves, using the notation of Aki and Richards (1980), is given by un(x, t) = (Dni/4πρc2R)∫∫s0τi3{ξ, t - [(R - ξ · γ)/c]} dS(ξ). Thus the far-field pulses can be directly found from the stress drops on the fault plane. This formula is also true for `crack' or `dislocation' problems. The directivity function Dni for displacement for the asperity problem is found to be that for the double couple, modified by some factor. In particular, the fault plane is a nodal plane for SV waves. For the rupturing of asperities on a finite fault, these directivity functions are applicable only to the initial part of observed pulses at a receiver, provided the receiver is not located on the fault plane outside the broken part of the main crack edge, in which case it is inapplicable for all

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

    NASA Technical Reports Server (NTRS)

    Saulsberry Regor

    2010-01-01

    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.

  16. Fan-head shear rupture mechanism as a source of off-fault tensile cracking

    NASA Astrophysics Data System (ADS)

    Tarasov, Boris

    2016-04-01

    This presentation discusses the role of a recently identified fan-head shear rupture mechanism [1] in the creation of off-fault tensile cracks observed in earthquake laboratory experiments conducted on brittle photoelastic specimens [2,3]. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength) and self-sustaining tensile stress intensification along one side of the interface. The variation of tensile stress within the fan-head zone is like this: it increases with distance from the fracture tip up to a maximum value and then decreases. For the initial formation of the fan-head high local stresses corresponding to the fracture strength should be applied in a small area, however after completions of the fan-head it can propagate dynamically through the material at low shear stresses (even below the frictional strength). The fan-mechanism allows explaining all unique features associated with the off-fault cracking process observed in photoelastic experiments [2,3]. In these experiments spontaneous shear ruptures were nucleated in a bonded, precut, inclined and pre-stressed interface by producing a local pressure pulse in a small area. Isochromatic fringe patterns around a shear rupture propagating along bonded interface indicate the following features of the off-fault tensile crack development: tensile cracks nucleate and grow periodically along one side of the interface at a roughly constant angle (about 80 degrees) relative to the shear rupture interface; the tensile crack nucleation takes place some distance behind the rupture tip; with distance from the point of nucleation tensile cracks grow up to a certain length within the rupture head zone

  17. Rupture characterization of the 2014 Napa Valley earthquake from 3 different perspectives

    NASA Astrophysics Data System (ADS)

    Cedric, T.; Adams, M.; Ji, C.; Archuleta, R. J.

    2014-12-01

    The extensive strong-ground motion data of the August 24 Mw 6.1 Napa Valley earthquake exhibits an interesting pattern of the strong ground motion. Although the slip models based on seismic and geodetic data revealed mainly north-north-west rupture propagation, the largest ground acceleration of 0.94g was observed at a station south of the hypocenter, presumably associated with the initiation stage of this earthquake. Here, the kinematic and dynamic rupture process of this earthquake is studied using the strong-ground motion data in the vicinity (< 40 km) of the epicentre of the Napa Valley earthquake. Three inversion algorithms are applied. First, a conventional non-linear finite fault inversion is conducted to constrain the overall slip history using relatively long period (> 1 s) seismic data. Second, a dynamic finite fault inversion, which approximates the rupture as multiple elliptical cracks, is carried out to understand what are the stress and strength conditions on the fault that produces a rupture history that is compatible with the observed data. Finally, an iterative Landweber back-projection algorithm is used to constrain the finer spatio-temporal rupture history associating with the high frequency radiation. The efforts particularly focus on the initiation stage of the fault rupture.

  18. Kinesthetic Transverse Wave Demonstration

    NASA Astrophysics Data System (ADS)

    Pantidos, Panagiotis; Patapis, Stamatis

    2005-09-01

    This is a variation on the String and Sticky Tape demonstration "The Wave Game," suggested by Ron Edge. A group of students stand side by side, each one holding a card chest high with both hands. The teacher cues the first student to begin raising and lowering his card. When he starts lowering his card, the next student begins to raise his. As succeeding students move their cards up and down, a wave such as that shown in the figure is produced. To facilitate the process, students' motions were synchronized with the ticks of a metronome (without such synchronization it was nearly impossible to generate a satisfactory wave). Our waves typically had a frequency of about 1 Hz and a wavelength of around 3 m. We videotaped the activity so that the students could analyze the motions. The (17-year-old) students had not received any prior instruction regarding wave motion and did not know beforehand the nature of the exercise they were about to carry out. During the activity they were asked what a transverse wave is. Most of them quickly realized, without teacher input, that while the wave propagated horizontally, the only motion of the transmitting medium (them) was vertical. They located the equilibrium points of the oscillations, the crests and troughs of the waves, and identified the wavelength. The teacher defined for them the period of the oscillations of the motion of a card to be the total time for one cycle. The students measured this time and then several asserted that it was the same as the wave period. Knowing the length of the waves and the number of waves per second, the next step can easily be to find the wave speed.

  19. Strength Testing.

    ERIC Educational Resources Information Center

    Londeree, Ben R.

    1981-01-01

    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)

  20. Simultaneous and spontaneous bilateral quadriceps tendons rupture.

    PubMed

    Celik, Evrim Coşkun; Ozbaydar, Mehmet; Ofluoglu, Demet; Demircay, Emre

    2012-07-01

    Simultaneous and spontaneous bilateral quadriceps tendon rupture is an uncommon injury that is usually seen in association with multiple medical conditions and some medications. We report a case of simultaneous and spontaneous bilateral quadriceps tendon rupture that may be related to the long-term use of a statin.

  1. Fractal avalanche ruptures in biological membranes

    NASA Astrophysics Data System (ADS)

    Gözen, Irep; Dommersnes, Paul; Czolkos, Ilja; Jesorka, Aldo; Lobovkina, Tatsiana; Orwar, Owe

    2010-11-01

    Bilayer membranes envelope cells as well as organelles, and constitute the most ubiquitous biological material found in all branches of the phylogenetic tree. Cell membrane rupture is an important biological process, and substantial rupture rates are found in skeletal and cardiac muscle cells under a mechanical load. Rupture can also be induced by processes such as cell death, and active cell membrane repair mechanisms are essential to preserve cell integrity. Pore formation in cell membranes is also at the heart of many biomedical applications such as in drug, gene and short interfering RNA delivery. Membrane rupture dynamics has been studied in bilayer vesicles under tensile stress, which consistently produce circular pores. We observed very different rupture mechanics in bilayer membranes spreading on solid supports: in one instance fingering instabilities were seen resulting in floral-like pores and in another, the rupture proceeded in a series of rapid avalanches causing fractal membrane fragmentation. The intermittent character of rupture evolution and the broad distribution in avalanche sizes is consistent with crackling-noise dynamics. Such noisy dynamics appear in fracture of solid disordered materials, in dislocation avalanches in plastic deformations and domain wall magnetization avalanches. We also observed similar fractal rupture mechanics in spreading cell membranes.

  2. Fractal avalanche ruptures in biological membranes.

    PubMed

    Gözen, Irep; Dommersnes, Paul; Czolkos, Ilja; Jesorka, Aldo; Lobovkina, Tatsiana; Orwar, Owe

    2010-11-01

    Bilayer membranes envelope cells as well as organelles, and constitute the most ubiquitous biological material found in all branches of the phylogenetic tree. Cell membrane rupture is an important biological process, and substantial rupture rates are found in skeletal and cardiac muscle cells under a mechanical load. Rupture can also be induced by processes such as cell death, and active cell membrane repair mechanisms are essential to preserve cell integrity. Pore formation in cell membranes is also at the heart of many biomedical applications such as in drug, gene and short interfering RNA delivery. Membrane rupture dynamics has been studied in bilayer vesicles under tensile stress, which consistently produce circular pores. We observed very different rupture mechanics in bilayer membranes spreading on solid supports: in one instance fingering instabilities were seen resulting in floral-like pores and in another, the rupture proceeded in a series of rapid avalanches causing fractal membrane fragmentation. The intermittent character of rupture evolution and the broad distribution in avalanche sizes is consistent with crackling-noise dynamics. Such noisy dynamics appear in fracture of solid disordered materials, in dislocation avalanches in plastic deformations and domain wall magnetization avalanches. We also observed similar fractal rupture mechanics in spreading cell membranes.

  3. [Premature rupture of membranes and chorioamnionitis].

    PubMed

    Lopez Garcia, R

    1988-01-01

    Despite advances in perinatal medicine in the past decade, the diagnosis and treatment of premature rupture of membranes remain controversial. Premature rupture occurs in 2.7-7.0% of pregnancies and most cases occur spontaneously without apparent cause. The disparity in reported rates of premature rupture is due to differences in the definition and diagnostic criteria for premature rupture and lack of comparability in the populations studied. Mexico's National Institute of Perinatology has adopted the definition of the American COllege of Gynecology and Obstetrics which views premature rupture as that occurring before regular uterine contractions that produce cervical dilation. 8.8% of its patients have premature rupture according to this definition. 20% of cases occur before the 36th week of pregnancy. Treatment of rupture occurring before 37 weeks must balance the threat of amniotic infection with the dangers of premature birth. Infections appear more common in low income patient populations. Chorioamnionitis is a serious complication of pregnancy and is the main argument against conservative treatment of premature rupture. The rate of maternal infection is directly related to the time elapsing between rupture of the membranes and birth. The rate increases after the 1st 24 hours and is at least 10 times higher after 72 hours. But recent studies suggest that there is no considerable increase in infection if vaginal explorations are avoided and careful techniques are used in treating the patient. Those who advise conservative treatment believe that prenatal outcomes are better because respiratory disease syndrome due to prematurity is avoided. Conservative management requires a white cell count at least every 24 hours and measurement of pulse, maternal temperature, and fetal heart rate ideally every 4 hours. Perinatal mortality rates due to premature rupture of membranes range from 2.5-50%. The principal causes are respiratory disease syndrome, infection, asphyxia

  4. Method and apparatus for determining tensile strength

    DOEpatents

    Ratigan, J.L.

    1982-05-28

    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.

  5. Method and apparatus for determining tensile strength

    DOEpatents

    Ratigan, Joe L.

    1984-01-01

    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.

  6. Risk Factors for Endometritis Following Low Transverse Cesarean Section

    PubMed Central

    OLSEN, Margaret A.; BUTLER, Anne M.; WILLERS, Denise M.; GROSS, Gilad A.; DEVKOTA, Preetishma; FRASER, Victoria J.

    2012-01-01

    Objective To determine independent risk factors for endometritis (EMM) following low transverse cesarean section (LTCS). Study design We performed a retrospective case-control study from July 1999 to June 2001 in a large tertiary-care academic hospital. EMM was defined as fever beginning > 24 hours or continuing for ≥ 24 hours after delivery plus fundal tenderness in the absence of other causes for fever. Independent risk factors for EMM were determined by multivariable logistic regression. A fractional polynomial method was used to examine risk of EMM associated with the continuous variable, duration of rupture of membranes. Results EMM was identified in 124/1605 (7.7%) women within 30 days after LTCS. Independent risk factors for EMM included age (odds ratio (OR) for each additional year 0.93; 95% confidence interval (CI): 0.90-0.97) and anemia/perioperative blood transfusion (OR 2.18; CI:1.30-3.68). Risk of EMM was marginally associated with a proxy for low socioeconomic status, lack of private health insurance (OR 1.72; CI: 0.99-3.00), amniotomy (OR 1.69; CI:0.97-2.95), and longer duration of rupture of membranes. Conclusion Risk of EMM was independently associated with younger age and anemia, and was marginally associated with lack of private health insurance, and amniotomy. Although duration of rupture of membranes was only marginally associated with increased risk of EMM, increased risk was observed very soon after rupture of membranes. Knowledge of these risk factors is important to guide selective use of prophylactic antibiotics during labor and heighten awareness of the risk in subgroups at highest risk of infection. PMID:19951198

  7. What does the transverse carpal ligament contribute to carpal stability?

    PubMed

    Vanhees, Matthias; Verstreken, Frederik; van Riet, Roger

    2015-02-01

    Background The transverse carpal ligament is well known for its involvement in carpal tunnel syndrome, and sectioning of this ligament remains the definite treatment for this pathology. Some authors believe that the transverse carpal ligament is an important stabilizer of the carpal arch, whereas others do not consider it to be significant. Several studies have been performed, both in vivo and in in vitro. Sectioning of the transverse carpal ligament does not seem to have any effect on the width of the carpal arch in the unloaded condition. However, patients will load the arch during their activities of daily living. Materials and Methods A cadaveric study was done with distraction of the carpal bones before and after sectioning the transverse carpal ligament. Results With the transverse carpal ligament intact, the carpal arch is mobile, with distraction leading up to 50% widening of the arch. Sectioning of the transverse carpal ligament resulted in a significant widening of the carpal arch by a further 30%. Conclusions Loading of the carpal arch after sectioning of the transeverse carapal ligament leads to a significant increase in intracarpal mobility. This will inevitably influence carpal kinematics in the patient and might be responsible for some complications after simple carpal tunnel releases, such as pillar pain, palmar tenderness, and loss of grip strength.

  8. Do buried-rupture earthquakes trigger less landslides than surface-rupture earthquakes for reverse faults?

    NASA Astrophysics Data System (ADS)

    Xu, Chong

    2014-07-01

    Gorum et al. (2013, Geomorphology 184, 127-138) carried out a study on inventory compilation and statistical analyses of landslides triggered by the 2010 Mw 7.0 Haiti earthquake. They revealed that spatial distribution patterns of these landslides were mainly controlled by complex rupture mechanism and topography. They also suggested that blind-rupture earthquakes trigger fewer landslides than surface-rupture earthquakes on thrust reverse faults. Although a few lines of evidence indicate that buried-rupture earthquakes might trigger fewer landslides than surface-rupture earthquakes on reverse faults, more careful comparisons and analyses indicate that it is not always true. Instead, some cases show that a buried-rupture earthquake can trigger a larger quantity of landslides that are distributed in a larger area, whereas surface-rupture earthquakes can trigger larger but a fewer landslides distributed in a smaller area.

  9. Fracture toughness and strength of 96% alumina

    SciTech Connect

    Price, D.B.; Chinn, R.E.; McNerney, K.R.; Brog, T.K.; Kim, C.Y.; Krutyholowa, M.W.; Chen, N.W.; Haun, M.J.

    1997-05-01

    There exists a need to understand the controlling factors that simultaneously impact strength and toughness in 96% alumina. The enhancement of both strength and toughness enables designers to extend the use limits and reliability for structural ceramics. This article presents mechanical property results from a group study examining the use of different alkaline-earth aluminosilicate intergranular compositions containing magnesium, calcium and strontium oxides (RO) in 96% alumina. Principal results address trends in indentation strength toughness and modulus of rupture. Trends in the data are presented relative to existing theories of thermal expansion mismatch toughening, grain-bridging crack-wake effect and crack deflection mechanisms. Strength is addressed in terms of strength after indentation, crack growth of indentation flaws and Weibull characterization for the strength distribution.

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

    PubMed

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

    2014-08-01

    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

  11. Transverse Momentum Fluctuations at RHIC

    NASA Astrophysics Data System (ADS)

    Gavin, Sean; Abdel-Aziz, Mohamed

    2004-10-01

    PHENIX and STAR data in Au+Au collisions at RHIC show that transverse momentum fluctuations increase as centrality increases. The approach to local thermal equilibrium can explain the similar centrality dependence of the average transverse momentum and its fluctuations [1]. Alternatively, this dependence can be attributed to jet effects, although the mechanism has not been spelled out in the literature [2]. Certainly both mechanisms play a role at some level. We review the nonequilibrium description of parton thermalization in [1]. We then extend the formulation to account for contributions to fluctuations from the energy loss of the high transverse momentum particles. Calculations are then compared to the measured average transverse momentum and its fluctuations. We then discuss how correlation function measurements may distinguish these effects. [1] Sean Gavin, Phys.Rev.Lett. 92 (2004) 162301. [2] S. S. Adler et al. [PHENIX Collaboration], arXiv:nucl-ex/0310005.

  12. New construction for transversal design.

    PubMed

    Du, Ding-Zhu; Hwang, F K; Wu, Weili; Znati, Taieb

    2006-05-01

    The study of gene functions requires the development of a DNA library of high quality through much of testing and screening. Pooling design is a mathematical tool to reduce the number of tests for DNA library screening. The transversal design is a special type of pooling design, which is good in implementation. In this paper, we present a new construction for transversal designs. We will also extend our construction to the error-tolerant case.

  13. Tensile creep and stress-rupture behavior of polymer derived SiC fibers

    SciTech Connect

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

    1994-08-01

    Tensile creep and stress-rupture studies were conducted on polymer derived Nicalon, Hi-Nicalon, and SiC/BN-coated Nicalon SiC fibers. Test conditions were temperatures from 1200 to 1400 C, stresses from 100 to 1600 MPa, stress application times up to 200 hours, and air, argon, and vacuum test environments. For all fibers, creep occurred predominantly in the primary stage. Hi-Nicalon had much higher 0.2 and 1 percent creep strengths than as-produced as well as-coated Nicalon fibers. The stress-rupture strength of Hi-Nicalon up to 100 hours was also higher than that of the coated and as-produced Nicalon fibers. SiC/BN coating on Nicalon increased only the short-term low-temperature rupture strength. Limited testing in argon and vacuum suggests that for all fiber types, creep and rupture resistances are reduced in comparison to the results in air. Possible mechanisms for the observed behavior are discussed.

  14. Tensile creep and stress-rupture behavior of polymer derived SiC fibers

    SciTech Connect

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

    1994-12-31

    Tensile creep and stress-rupture studies were conducted on polymer derived Nicalon, Hi-Nicalon, and SiC/BN-coated Nicalon SiC fibers. Test conditions were temperatures from 1200 to 1400{degrees}C, stresses from 100 to 1600 MPa, stress application times up to 200 hours, and air, argon, and vacuum test environments. For all fibers, creep occurred predominantly in the primary stage. Hi-Nicalon had much higher 0.2 and 1% creep strengths than as-produced as well as coated Nicalon fibers. The stress-rupture strength of Hi-Nicalon up to 100 hours was also higher than that of the coated and as-produced Nicalon fibers. SiC/BN coating on Nicalon increased only the short-term low-temperature rupture strength. Limited testing in argon and vacuum suggests that for all fiber types, creep and rupture resistances are reduced in comparison to the results in air. Possible mechanisms for the observed behavior are discussed.

  15. Spontaneous rupture of the spleen operated in gynecological unit mistaken for ruptured hemorrhagic ovarian cyst: total splenectomy

    PubMed Central

    Eko, Filbert Eko; Fouelifack, Florent Ymele; de Paul, Elanga Vincent

    2014-01-01

    Spontaneous splenic rupture is always neglected when consulting acute abdominal pains in gynecological emergencies. It constitutes about 1% of all splenic ruptures and can be managed by abstention, surgery or embolization. We present the case of a young lady who was diagnosed of spontaneous rupture during surgery that was mistaken for ruptured hemorrhagic ovarian cyst and finally treated by total splenectomy. The pre-operative work up was absolute for a rupturred hemorrhagic cyst and secondariy for a ruptured ectopic gestation. PMID:25918564

  16. TRANSVERSE OSCILLATIONS IN CHROMOSPHERIC MOTTLES

    SciTech Connect

    Kuridze, D.; Mathioudakis, M.; Jess, D. B.; Keenan, F. P.; Morton, R. J.; Erdelyi, R.; Dorrian, G. D.

    2012-05-01

    A number of recent investigations have revealed that transverse waves are ubiquitous in the solar chromosphere. The vast majority of these have been reported in limb spicules and active region fibrils. We investigate long-lived, quiet-Sun, on-disk features such as chromospheric mottles (jet-like features located at the boundaries of supergranular cells) and their transverse motions. The observations were obtained with the Rapid Oscillations in the Solar Atmosphere instrument at the Dunn Solar Telescope. The data set is comprised of simultaneous imaging in the H{alpha} core, Ca II K, and G band of an on-disk quiet-Sun region. Time-distance techniques are used to study the characteristics of the transverse oscillations. We detect over 40 transverse oscillations in both bright and dark mottles, with periods ranging from 70 to 280 s, with the most frequent occurrence at {approx}165 s. The velocity amplitudes and transverse displacements exhibit characteristics similar to limb spicules. Neighboring mottles oscillating in-phase are also observed. The transverse oscillations of individual mottles are interpreted in terms of magnetohydrodynamic kink waves. Their estimated periods and damping times are consistent with phase mixing and resonant mode conversion.

  17. Aneurysm strength can decrease under calcification.

    PubMed

    Volokh, Konstantin Y; Aboudi, Jacob

    2016-04-01

    Aneurysms are abnormal dilatations of vessels in the vascular system that are prone to rupture. Prediction of the aneurysm rupture is a challenging and unsolved problem. Various factors can lead to the aneurysm rupture and, in the present study, we examine the effect of calcification on the aneurysm strength by using micromechanical modeling. The calcified tissue is considered as a composite material in which hard calcium particles are embedded in a hyperelastic soft matrix. Three experimentally calibrated constitutive models incorporating a failure description are used for the matrix representation. Two constitutive models describe the aneurysmal arterial wall and the third one - the intraluminal thrombus. The stiffness and strength of the calcified tissue are simulated in uniaxial tension under the varying amount of calcification, i.e. the relative volume of the hard inclusion within the periodic unit cell. In addition, the triaxiality of the stress state, which can be a trigger for the cavitation instability, is tracked. Results of the micromechanical simulation show an increase of the stiffness and a possible decrease of the strength of the calcified tissue as compared to the non-calcified one. The obtained results suggest that calcification (i.e. the presence of hard particles) can significantly affect the stiffness and strength of soft tissue. The development of refined experimental techniques that will allow for the accurate quantitative assessment of calcification is desirable. PMID:26717251

  18. Metrics for comparing dynamic earthquake rupture simulations

    USGS Publications Warehouse

    Barall, Michael; Harris, Ruth A.

    2014-01-01

    Earthquakes are complex events that involve a myriad of interactions among multiple geologic features and processes. One of the tools that is available to assist with their study is computer simulation, particularly dynamic rupture simulation. A dynamic rupture simulation is a numerical model of the physical processes that occur during an earthquake. Starting with the fault geometry, friction constitutive law, initial stress conditions, and assumptions about the condition and response of the near‐fault rocks, a dynamic earthquake rupture simulation calculates the evolution of fault slip and stress over time as part of the elastodynamic numerical solution (Ⓔ see the simulation description in the electronic supplement to this article). The complexity of the computations in a dynamic rupture simulation make it challenging to verify that the computer code is operating as intended, because there are no exact analytic solutions against which these codes’ results can be directly compared. One approach for checking if dynamic rupture computer codes are working satisfactorily is to compare each code’s results with the results of other dynamic rupture codes running the same earthquake simulation benchmark. To perform such a comparison consistently, it is necessary to have quantitative metrics. In this paper, we present a new method for quantitatively comparing the results of dynamic earthquake rupture computer simulation codes.

  19. Age at intracranial aneurysm rupture among generations

    PubMed Central

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

    2009-01-01

    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 “anticipation.” 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

  20. Extracellular matrix content of ruptured anterior cruciate ligament tissue.

    PubMed

    Young, Kate; Samiric, Tom; Feller, Julian; Cook, Jill

    2011-08-01

    Anterior cruciate ligaments (ACLs) can rupture with simple movements, suggesting that structural changes in the ligament may reduce the loading capacity of the ligament. We aimed to investigate if proteoglycan and collagen levels were different between ruptured and non-ruptured ACLs. We also compared changes in ruptured tissue over time. During arthroscopic knee reconstruction surgery 24 ruptured ACLs were collected from participants (10 females; 14 males; mean age 24 years). Four non-ruptured ACLs were obtained from participants undergoing total knee replacement surgery (one female, three males; mean age 66 years). Western blot analysis was used to characterise core proteins of aggrecan, versican, decorin and biglycan and glycosaminoglycan assays were also conducted. Collagen levels were measured by hydroxyproline (OHPr) assays. Significantly lower levels of collagen, were found in ruptured ACL compared to non-ruptured ACL (p=0.004). Lower levels of both small and large proteoglycans were found in ruptured than non-ruptured ACLs. No correlation was found between time since rupture and proteoglycan or collagen levels. Ruptured ACLs had less collagen and proteoglycans than non-ruptured ACLs. These changes indicate either extracellular matrix protein levels were reduced prior to rupture or levels decreased immediately after rupture. It is possible that the composition and structure of ACLs that rupture are different to normal ACLs, potentially reducing the tissue's ability to withstand loading. An enhanced understanding of the aetiology of ACL injury could help identify individuals who may be predisposed to rupture.

  1. Misdiagnosed Chest Pain: Spontaneous Esophageal Rupture

    PubMed Central

    Inci, Sinan; Gundogdu, Fuat; Gungor, Hasan; Arslan, Sakir; Turkyilmaz, Atila; Eroglu, Atila

    2013-01-01

    Chest pain is one of themost common complaints expressed by patients presenting to the emergency department, and any initial evaluation should always consider life-threatening causes. Esophageal rupture is a serious condition with a highmortality rate. If diagnosed, successful therapy depends on the size of the rupture and the time elapsed between rupture and diagnosis.We report on a 41-year-old woman who presented to the emergency department complaining of left-sided chest pain for two hours. PMID:27122690

  2. Expanding Endovascular Therapy of Very Small Ruptured Aneurysms with the 1.5-mm Coil

    PubMed Central

    Nguyen, Thanh N.; Masoud, Hesham; Tarlov, Nicholas; Holsapple, James; Chin, Lawrence S.; Norbash, Alexander M.

    2015-01-01

    Background Very small ruptured aneurysms (≤3 mm) demonstrate a significant risk for procedural rupture with endovascular therapy. Since 2007, 1.5-mm-diameter coils have been available (Micrus, Microvention, and ev3), allowing neurointerventionalists the opportunity to offer patients with very small aneurysms endovascular treatment. In this study, we review the clinical and angiographic outcome of patients with very small ruptured aneurysms treated with the 1.5-mm coil. Methods This is a retrospective cohort study in which we examined consecutive ruptured very small aneurysms treated with coil embolization at a single institution. The longest linear aneurysm was recorded, even if the first coil was sized to a smaller transverse diameter. Very small aneurysms were defined as ≤3 mm. Descriptive results are presented. Results From July 2007 to March 2015, 81 aneurysms were treated acutely with coils in 78 patients presenting with subarachnoid hemorrhage. There were 5 patients with 3-mm aneurysms, of which the transverse diameter was ≤2 mm in 3 patients. In all 5 patients, a balloon was placed for hemostatic prophylaxis in case of rupture, and a single 1.5-mm coil was inserted for aneurysm treatment without complication. Complete aneurysm occlusion was achieved in 1 patient, residual neck in 2, and residual aneurysm in 2 patients. Aneurysm recanalization was present in 2 patients with an anterior communicating artery aneurysm; a recoiling attempt was unsuccessful in 1 of these 2 patients due to inadvertent displacement and distal coil embolization, but subsequent surgical clipping was successful. Another patient was retreated by surgical clipping for a residual wide-neck carotid terminus aneurysm. One patient died of ventriculitis 3 weeks after presentation; all 4 other patients had an excellent outcome with no rebleed at follow-up (mean 21 months, range 1-62). Conclusion The advent of the 1.5-mm coil may be used in the endovascular treatment of patients with very

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    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.

  4. Earthquake Rupturing in Fluid-Overpressured Crust: How Common?

    NASA Astrophysics Data System (ADS)

    Sibson, Richard H.

    2014-11-01

    Whether or not ruptures nucleate in fluid-overpressured crust ( λ v = P f/ σ v > 0.4) is important because pore-fluids overpressured above hydrostatic lower fault frictional strength and may also vary through the earthquake cycle, acting as an independent variable affecting fault failure. Containment of fluid overpressure is precarious because pressure-dependent activation of faults and fractures allows drainage from overpressured portions of the crust. Discharge of fluids through activated fault-fracture permeability (fault-valve action) decreases overpressure so that subsequent failure depends on the cycling of both overpressure and frictional strength as well as tectonic stress. Geometric and mechanical considerations suggest that fluid overpressures are more likely to develop and be sustained in compressional/transpressional regimes as opposed to extensional/transtensional tectonic settings. On the basis of geophysical observations and force-balance analyses, subduction interface shear zones appear to be strongly but variably overpressured to near-lithostatic levels ( λ v > 0.9) over the full depth range of seismogenic megathrusts. Strong overpressuring at seismogenic depths is also documented in active fold-thrust belts and in areas of ongoing compressional inversion (e.g., northern Honshu) where inherited normal faults are reactivated as steep reverse faults, requiring near-lithostatic overpressures ( λ v → 1.0) at depths of rupture initiation. Evidence for overpressuring around strike-slip faults is less clear but tends to be strongest in areas of transpression. In areas of extensional tectonics coincident with particularly high fluid discharge, there is some evidence of overpressuring concentrated towards the base of the seismogenic zone. In general, because of the limited resolution of geophysical techniques, it is easier to make the case for rupture propagation through overpressured crust than to make a definitive case for the direct involvement of

  5. Subducting plate geology in three great earthquake ruptures of the western Alaska margin, Kodiak to Unimak

    USGS Publications Warehouse

    von Huene, Roland; Miller, John J.; Weinrebe, Wilhelm

    2012-01-01

    Three destructive earthquakes along the Alaska subduction zone sourced transoceanic tsunamis during the past 70 years. Since it is reasoned that past rupture areas might again source tsunamis in the future, we studied potential asperities and barriers in the subduction zone by examining Quaternary Gulf of Alaska plate history, geophysical data, and morphology. We relate the aftershock areas to subducting lower plate relief and dissimilar materials in the seismogenic zone in the 1964 Kodiak and adjacent 1938 Semidi Islands earthquake segments. In the 1946 Unimak earthquake segment, the exposed lower plate seafloor lacks major relief that might organize great earthquake rupture. However, the upper plate contains a deep transverse-trending basin and basement ridges associated with the Eocene continental Alaska convergent margin transition to the Aleutian island arc. These upper plate features are sufficiently large to have affected rupture propagation. In addition, massive slope failure in the Unimak area may explain the local 42-m-high 1946 tsunami runup. Although Quaternary geologic and tectonic processes included accretion to form a frontal prism, the study of seismic images, samples, and continental slope physiography shows a previous history of tectonic erosion. Implied asperities and barriers in the seismogenic zone could organize future great earthquake rupture.

  6. Dynamic Rupture and Ground Motion Modeling on Realistically Complex Strike-Slip Faults

    NASA Astrophysics Data System (ADS)

    Lozos, Julian Charles

    Faults are complex structures: they are geometrically complex, and have variable stress conditions and frictional behaviors along their length. In addition, faults exist in heterogeneous settings, in terms of surrounding geology, and in terms of regional and local stresses. These individual types of heterogeneity all contribute to complex dynamic rupture behaviors and ground motion distributions, as inferred from observational data and supported by previous modeling studies. In this study, we investigate the effects of individual types of complexity, and we combine different types of heterogeneity in order to enhance the realism of models of real-world faults. We use the finite element method to conduct dynamic rupture models of earthquakes on faults with complex geometry, initial stresses, frictional parameters, and surrounding geology, and with combinations of these factors, in order to investigate the effects of this complexity on fault interactions, rupture extent, and ground motion. In particular, we investigate the effect of critical weakening distance on the ability of rupture to propagate through a discontinuity in the fault trace, the effect of a small fault between the larger strands of a stepover on the ability of rupture to jump the stepover, and how zones of aseismic creep affect rupture through locked portions of the same fault. We also construct realistically complex models of the northern San Jacinto Fault, California, incorporating realistic geometry, velocity structure, and combined regional and stochastic stress fields. We find that the distribution of complexity of any type on the fault, which leads to heterogeneous fault strength, has the primary controlling effect on rupture behavior. The relative strength or weakness of the fault, rather than the actual value, is most important. We also find that the balance of the energy budget is crucial; if too much energy is redirected into fracture, rupture stops. Lastly, we find that each type of

  7. Transverse deformations of extreme horizons

    NASA Astrophysics Data System (ADS)

    Li, Carmen; Lucietti, James

    2016-04-01

    We consider the inverse problem of determining all extreme black hole solutions to the Einstein equations with a prescribed near-horizon geometry. We investigate this problem by considering infinitesimal deformations of the near-horizon geometry along transverse null geodesics. We show that, up to a gauge transformation, the linearised Einstein equations reduce to an elliptic PDE for the extrinsic curvature of a cross-section of the horizon. We deduce that for a given near-horizon geometry there exists a finite dimensional moduli space of infinitesimal transverse deformations. We then establish a uniqueness theorem for transverse deformations of the extreme Kerr horizon. In particular, we prove that the only smooth axisymmetric transverse deformation of the near-horizon geometry of extreme Kerr, such that cross-sections of the horizon are marginally trapped surfaces, corresponds to that of the extreme Kerr black hole. Furthermore, we determine all smooth and biaxisymmetric transverse deformations of the near-horizon geometry of the five-dimensional extreme Myers-Perry black hole with equal angular momenta. We find a three parameter family of solutions such that cross-sections of the horizon are marginally trapped, which is more general than the known black hole solutions. We discuss the possibility that they correspond to new five-dimensional vacuum black holes.

  8. Cryogenic insulation strength and bond tester

    NASA Technical Reports Server (NTRS)

    Schuerer, P. H.; Ehl, J. H.; Prasthofer, W. P. (Inventor)

    1985-01-01

    A method and apparatus for testing the tensile strength and bonding strength of sprayed-on foam insulation attached to metal cryogenic fuel tanks is described. A circular cutter is used to cut the insulation down to the surface of the metal tank to form plugs of the insulation for testing in situ on the tank. The apparatus comprises an electromechanical pulling device powered by a belt battery pack. The pulling device comprises a motor driving a mechanical pulling structure comprising a horizontal shaft connected to two bell cracks which are connected to a central member. When the lower end of member is attached to a fitting, which in turn is bonded to a plug, a pulling force is exerted on the plug sufficient to rupture it. The force necessary to rupture the plug or pull it loose is displayed as a digital read-out.

  9. High-strength iron aluminide alloys

    SciTech Connect

    McKamey, C.G.; Maziasz, P.J.

    1996-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  10. Spontaneous rupture of the abdominal aorta.

    PubMed Central

    Williams, T. G.

    1977-01-01

    Fatal spontaneous rupture of the lower abdominal aorta in a previously healthy 61-year-old woman is reported; the possibility that she had the Ehlers-Danlos syndrome is discussed. Images Fig. 1 PMID:870895

  11. Traumatic Gallbladder Rupture Treated by Laparoscopic Cholecystectomy.

    PubMed

    Egawa, Noriyuki; Ueda, Junji; Hiraki, Masatsugu; Ide, Takao; Inoue, Satoshi; Sakamoto, Yuichiro; Noshiro, Hirokazu

    2016-01-01

    Gallbladder rupture due to blunt abdominal injury is rare. There are few reports of traumatic gallbladder injury, and it is commonly associated with other concomitant visceral injuries. Therefore, it is difficult to diagnose traumatic gallbladder rupture preoperatively when it is caused by blunt abdominal injury. We report a patient who underwent laparoscopic cholecystectomy after an exact preoperative diagnosis of traumatic gallbladder rupture. A 43-year-old man was admitted to our hospital due to blunt abdominal trauma. The day after admission, abdominal pain and ascites increased and a muscular defense sign appeared. Percutaneous drainage of the ascites was performed, and the aspirated fluid was bloody and almost pure bile. He was diagnosed with gallbladder rupture by the cholangiography using the endoscopic retrograde cholangiopancreatography technique. Laparoscopic cholecystectomy was performed safely, and he promptly recovered. If accumulated fluids contain bile, endoscopic cholangiography is useful not only to diagnose gallbladder injury but also to determine the therapeutic strategy. PMID:27462188

  12. Pregnancy-related rupture of arterial aneurysms.

    PubMed

    Barrett, J M; Van Hooydonk, J E; Boehm, F H

    1982-09-01

    Over 50 per cent of ruptured arterial aneurysms in women under the age of 40 are pregnancy-related. The hemodynamic and endocrine changes of pregnancy appear to be the cause of arterial alterations which may lead to new aneurysm formation and/or weakening of preexisting aneurysms. The most commonly reported arteries to have aneurysms rupture during pregnancy are the aorta, cerebral arteries, splenic artery, renal artery, coronary artery, and ovarian artery. In many instances, the rupture of an arterial aneurysm will initially simulate other less serious disease processes, thus delaying the correct diagnosis until a catastrophic event occurs. Early diagnosis and treatment of a ruptured arterial aneurysm are imperative in order to give optimal chances of survival to the mother and fetus.

  13. Traumatic Gallbladder Rupture Treated by Laparoscopic Cholecystectomy

    PubMed Central

    Egawa, Noriyuki; Ueda, Junji; Hiraki, Masatsugu; Ide, Takao; Inoue, Satoshi; Sakamoto, Yuichiro; Noshiro, Hirokazu

    2016-01-01

    Abstract Gallbladder rupture due to blunt abdominal injury is rare. There are few reports of traumatic gallbladder injury, and it is commonly associated with other concomitant visceral injuries. Therefore, it is difficult to diagnose traumatic gallbladder rupture preoperatively when it is caused by blunt abdominal injury. We report a patient who underwent laparoscopic cholecystectomy after an exact preoperative diagnosis of traumatic gallbladder rupture. A 43-year-old man was admitted to our hospital due to blunt abdominal trauma. The day after admission, abdominal pain and ascites increased and a muscular defense sign appeared. Percutaneous drainage of the ascites was performed, and the aspirated fluid was bloody and almost pure bile. He was diagnosed with gallbladder rupture by the cholangiography using the endoscopic retrograde cholangiopancreatography technique. Laparoscopic cholecystectomy was performed safely, and he promptly recovered. If accumulated fluids contain bile, endoscopic cholangiography is useful not only to diagnose gallbladder injury but also to determine the therapeutic strategy. PMID:27462188

  14. Cognitive frames in psychology: demarcations and ruptures.

    PubMed

    Yurevich, Andrey V

    2009-06-01

    As there seems to be a recurrent feeling of crisis in psychology, its present state is analyzed in this article. The author believes that in addition to the traditional manifestations that have dogged psychology since it emerged as an independent science some new features of the crisis have emerged. Three fundamental "ruptures" are identified: the "horizontal" rupture between various schools and trends, the "vertical" rupture between natural science and humanitarian psychology, and the "diagonal" rupture between academic research and applied practice of psychology. These manifestations of the crisis of psychology have recently been compounded by the crisis of its rationalistic foundations. This situation is described in terms of the cognitive systems in psychology which include meta-theories, paradigms, sociodigms and metadigms.

  15. Strength nutrition.

    PubMed

    Volek, Jeff S

    2003-08-01

    Muscle strength is determined by muscle size and factors related to neural recruitment. Resistance training is a potent stimulus for increasing muscle size and strength. These increases are, to a large extent, influenced and mediated by changes in hormones that regulate important events during the recovery process following exercise. Provision of nutrients in the appropriate amounts and at the appropriate times is necessary to optimize the recovery process. This review discusses the results of research that has examined the potential for nutrition and dietary supplements to impact the acute response to resistance exercise and chronic adaptations to resistance training. To date, the most promising strategies to augment gains in muscle size and strength appear to be consumption of protein-carbohydrate calories before and after resistance exercise, and creatine supplementation.

  16. Quadriceps tendon rupture through a superolateral bipartite patella.

    PubMed

    Woods, G William; O'Connor, Daniel P; Elkousy, Hussein A

    2007-10-01

    We report a case of a quadriceps tendon rupture through a bipartite patella. Although quadriceps tendon ruptures and patella fractures are common, rupture through a bipartite patella fragment is rare. This case was managed similar to a quadriceps rupture with an excellent result.

  17. [Spontaneous uterine rupture due to uterine leiomyosarcoma].

    PubMed

    Boussouni, Khouloud; Benoulaid, Meryem; Dafiri, Rachida

    2016-01-01

    Uterine sarcomas are rare cancers characterized by clinical and histological polymorphism. They are malignant tumors of poor prognosis. Inaugural manifestation of acute abdomen with hemo-pneumoperitoneum and spontaneous uterine rupture remains exceptional. The authors report the case of a uterine leiomyosarcoma manifesting itself as an inaugural generalized acute peritonitis in a 43 year old woman. Uterine rupture due to malignant tumor was suspected during urgent preoperative imaging (ultrasound and CT scan) and confirmed histologically. PMID:27642425

  18. Off-fault tensile cracks: A link between geological fault observations, experiments and earthquake rupture models

    NASA Astrophysics Data System (ADS)

    Ngo, D.; Huang, Y.; Rosakis, A.; Griffith, W. A.; Pollard, D. D.

    2009-12-01

    Motivated by the occurrence of high-angle pseudotachylite injection veins along exhumed faults, we use optical experiments and high-speed photography to interpret the origins of tensile fractures that form during dynamic shear rupture in laboratory experiments. Sub-Rayleigh (slower than the Rayleigh wave speed) shear ruptures in Homalite-100 produce damage zones consisting of a periodic array of tensile cracks. These cracks nucleate and grow within cohesive zones behind the tips of shear ruptures that propagate dynamically along interfaces with frictional and cohesive strength. The tensile cracks are produced only along one side of the interface where transient, fault-parallel, tensile stress perturbations are associated with the growing shear rupture tip. We use an analytical, linear velocity weakening, rupture model to examine the local nature of the dynamic stress field in the vicinity of the tip of the main shear rupture which grows along a weak plane (fault) with sub-Rayleigh speed. It is this stress field which is responsible for driving the off-fault mode-I microcracks that grow during the experiments. We show that (1) the orientation of the cracks can be explained by this analytical model; and (2) the cracks can be used to simultaneously constrain the constitutive behavior of the shear rupture tip. In addition, we propose an extension of this model to explain damage structures observed along exhumed faults. Results of this study represent an important bridge between geological observations of structures preserved along exhumed faults, laboratory experiments and theoretical models of earthquake propagation, potentially leading to diagnostic criteria for interpreting velocity, directivity, and static pre-stress state associated with past earthquakes on exhumed faults.

  19. Transversely isotropic elasticity imaging of cancellous bone.

    PubMed

    Shore, Spencer W; Barbone, Paul E; Oberai, Assad A; Morgan, Elise F

    2011-06-01

    , the effects of noise on reconstruction quality is demonstrated and a signal-to-noise ratio (SNR) of 40 dB is identified as a reasonable threshold for obtaining accurate reconstructions from experimental data. This study demonstrates that given an appropriate set of displacement fields, level of regularization, and signal strength, the transversely isotropic method can recover the relative magnitudes of all five elastic parameters without an independent measurement of stress. The quality of the reconstructions improves with increasing contrast, magnitude of deformation, and asymmetry in the distributions of material properties, indicating that elasticity imaging of cancellous bone could be a useful tool in laboratory studies to monitor the progression of damage and disease in this tissue. PMID:21744922

  20. Realizing vector meson dominance with transverse charge densities

    SciTech Connect

    Gerald Miller, Mark Strikman, Christian Weiss

    2011-10-01

    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.

  1. Flutter analysis using transversality theory

    NASA Technical Reports Server (NTRS)

    Afolabi, D.

    1993-01-01

    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.

  2. UTERINE RUPTURE FOLLOWING MYOMECTOMY IN THIRD TRIMESTER.

    PubMed

    Djaković, Ivka; Rudman, Senka Sabolović; Kosec, Vesna

    2015-12-01

    Rupture of gravid uterus is surgical emergency causing maternal and fetal morbidity and mortality. The risk of uterine rupture is associated with uterine scars caused by previous cesarean section, myomectomy, hysteroscopic procedures, and curettage. We report a case of a 40-year-old woman in 31st week of gestation with spontaneous uterine rupture. It was her third pregnancy. She had two healthy children from previous pregnancies. Her symptoms were abdominal pain, vomiting and pain in the right shoulder lasting for 12 hours prior to admission. Ultrasound examination at admission revealed a dead fetus in the abdomen and free fluid in the abdominal cavity. She had previously undergone laparoscopic myomectomy. After myomectomy, she had one successful vaginal delivery. Every abdominal pain in pregnant woman with uterine scar should be carefully and promptly examined to exclude uterine rupture before further diagnostic procedures. This early time frame is essential for survival of the fetus and sometimes even of the mother. Uterine rupture represents indication for immediate cesarean section and it should be performed within 25 minutes of the first signs of uterine rupture. As shown in the case presented, one successful vaginal delivery after myomectomy is no guarantee for future pregnancies.

  3. Fatigue and plaque rupture in myocardial infarction.

    PubMed

    Versluis, Antheunis; Bank, Alan J; Douglas, William H

    2006-01-01

    Plaque rupture plays a role in the majority of acute coronary syndromes. Rupture has been associated with stress concentrations, which are affected by tissue properties and anatomy. In this study rupture was not approached as an acute syndrome, but rather as the culmination of a chronic injury or fatigue process. The aim of our study was to investigate the impact of anatomy, tissue properties, and blood pressure on a fatigue mechanism. Incremental crack propagation was dynamically simulated based on evolving stress distributions. Stresses were resolved by a finite element solver, using vessel stiffness properties derived from in vivo data. Plaque fatigue crack growth per pressure pulse was estimated using an adapted Paris-relation. It was demonstrated that cracks begin at the lumen wall at areas of stress concentration, depending on the shape of the lumen, thickness of the fibrous cap and stiffness of the plaque components. Mean or pulse pressure did not affect initiation location. Cracks extended radially and grew at a rate that was highly dependent on both mean and pulse pressure and on lipid stiffness. Rupture rate depended on blood pressure and lipid stiffness. It was concluded that a fatigue mechanism in a pulsatile cardiovascular pressure environment reconciles clinical evidence of acute plaque rupture at seemingly low stress levels, and it could provide a framework for developing strategies to create a biomechanically benign environment which is least conducive to plaque rupture.

  4. Yield Stress Effects on Mucus Plug Rupture

    NASA Astrophysics Data System (ADS)

    Hu, Yingying; Bian, Shiyao; Grotberg, John C.; Takayama, Shuichi; Grotberg, James B.

    2012-11-01

    Mucus plugs can obstruct airways, resulting in lost gas exchange and inflammation. Yield stress, one of the significant rheological properties of mucus, plays a significant role in plug rupture. We use carbopol 940 gels as mucus simulants to study dynamics of mucus plug rupture in experiments. Yield stress increases with gel concentration increasing (0.1% ~0.3%). The yield stress of the 0.2% gel is about 530 dyn/cm2, which can simulate normal mucus. A 2D PDMS channel is used to simulate a collapsed airway of the 12th generation in a human lung. Plug rupture is driven by a pressure drop of 1.6 ×104 ~ 2.0 ×104 dyn/cm2. Initial plug length varies from half to two times the half channel width. A micro-PIV technique is used to acquire velocity fields during rupture, from which wall shear stress is derived. Plug shortening velocity increases with the pressure drop, but decreases with yield stress or the initial plug length. Wall shear stress increases with yield stress, which indicates more potential damage may occur to epithelial cells when pathologic mucus has a high yield stress. Near the rupture moment, a wall shear stress peak appears at the front of the film deposited by the plug during rupture. This work is supported by NIH: HL84370 and HL85156.

  5. Tensile and stress-rupture behavior of hafnium carbide dispersed molybdenum and tungsten base alloy wires

    NASA Technical Reports Server (NTRS)

    Yun, Hee Mann; Titran, Robert H.

    1993-01-01

    The tensile strain rate sensitivity and the stress-rupture strength of Mo-base and W-base alloy wires, 380 microns in diameter, were determined over the temperature range from 1200 K to 1600 K. Three molybdenum alloy wires; Mo + 1.1w/o hafnium carbide (MoHfC), Mo + 25w/o W + 1.1w/o hafnium carbide (MoHfC+25W) and Mo + 45w/o W + 1.1w/o hafnium carbide (MoHfC+45W), and a W + 0.4w/o hafnium carbide (WHfC) tungsten alloy wire were evaluated. The tensile strength of all wires studied was found to have a positive strain rate sensitivity. The strain rate dependency increased with increasing temperature and is associated with grain broadening of the initial fibrous structures. The hafnium carbide dispersed W-base and Mo-base alloys have superior tensile and stress-rupture properties than those without HfC. On a density compensated basis the MoHfC wires exhibit superior tensile and stress-rupture strengths to the WHfC wires up to approximately 1400 K. Addition of tungsten in the Mo-alloy wires was found to increase the long-term stress rupture strength at temperatures above 1400 K. Theoretical calculations indicate that the strength and ductility advantage of the HfC dispersed alloy wires is due to the resistance to recrystallization imparted by the dispersoid.

  6. Transverse stresses and modes of failure in tree branches and other beams

    PubMed Central

    Ennos, A. R.; van Casteren, A.

    2010-01-01

    The longitudinal stresses in beams subjected to bending also set up transverse stresses within them; they compress the cross section when the beam's curvature is being increased and stretch it when its curvature is being reduced. Analysis shows that transverse stresses rise to a maximum at the neutral axis and increase with both the bending moment applied and the curvature of the beam. These stresses can qualitatively explain the fracture behaviour of tree branches. Curved ‘hazard beams’ that are being straightened split down the middle because of the low transverse tensile strength of wood. By contrast, straight branches of light wood buckle when they are bent because of its low transverse compressive strength. Branches of denser wood break, but the low transverse tensile strength diverts the crack longitudinally when the fracture has only run half-way across the beam, to produce their characteristic ‘greenstick fracture’. The bones of young mammals and uniaxially reinforced composite beams may also be prone to greenstick fracture because of their lower transverse tensile strength. PMID:20018786

  7. Transverse modes in microchip lasers

    SciTech Connect

    Sanchez, F.; Chardon, A.

    1996-12-01

    Two analytical sets of transverse eigenmodes are proposed for microchip lasers in one-dimensional geometry. Each set is associated with a particular pump profile. The eigenfunctions are expressed as Bessel or modified Bessel functions. {copyright} {ital 1996 Optical Society of America.}

  8. Transverse effects in UV FELs

    SciTech Connect

    Small, D.W.; Wong, R.K.; Colson, W.B.

    1995-12-31

    In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium`s UV FEL.

  9. Transverse Magnetic Field Propellant Isolator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2000-01-01

    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.

  10. A creep-rupture model of filament-wound spherical pressure vessels

    NASA Technical Reports Server (NTRS)

    Dozier, Jan D.; Hackett, Robert M.

    1987-01-01

    The creep-rupture model is that of a quasi-isotropic filament-wound spherical pressure vessel, subjected to internal pressurization. The matrix material of the composite system is assumed to be linearly viscoelastic. Internal damage resulting from the relaxation of the matrix and the corresponding increase in microcracks is represented by a functional relationship between circumferential strain and transverse modulus. The numerical solution to this nonlinear problem is an iterative technique, whereby the elastic-viscoelastic correspondence principle is employed. In the Laplace domain, the associated elastic solution is obtained and this solution is inverted by the multidata method to yield the time-dependent solution.

  11. Surgical Strategies for Acutely Ruptured Arteriovenous Malformations.

    PubMed

    Martinez, Jaime L; Macdonald, R Loch

    2015-01-01

    Brain arteriovenous malformations (AVMs) are focal neurovascular lesions consisting of abnormal fistulous connections between the arterial and venous systems with no interposed capillaries. This arrangement creates a high-flow circulatory shunt with hemorrhagic risk and hemodynamic abnormalities. While most AVMs are asymptomatic, they may cause severe neurological complications and death. Each AVM carries an annual rupture risk of 2-4%. Intracranial hemorrhage due to AVM rupture is the most common initial manifestation (up to 70% of presentations), and it carries significant morbidity and mortality. This complication is particularly important in the young and otherwise healthy population, in whom AVMs cause up to one-third of all hemorrhagic strokes. A previous rupture is the single most important independent predictor of future hemorrhage. Current treatment modalities for AVM are microsurgery, endovascular embolization, and radiosurgery. In acutely ruptured AVMs, early microsurgical excision is usually avoided. The standard is to wait at least 4 weeks to allow for patient recovery, hematoma liquefaction, and inflammatory reactions to subside. Exceptions to this rule are small, superficial, low-grade AVMs with elucidated angioarchitecture, for which early simultaneous hematoma evacuation and AVM excision is feasible. Emergent hematoma evacuation with delayed AVM excision (unless, as mentioned, the AVM is low grade) is recommended in patients with a decreased level of consciousness due to intracranial hemorrhage, posterior fossa or temporal lobe hematoma of >30 ml, or hemispheric hematoma of >60 ml. The applicability of endovascular techniques for acutely ruptured AVMs is not clear, but feasible options, until a definitive treatment is determined, include occluding intranidal and distal flow-related aneurysms and 'sealing' any rupture site or focal angioarchitectural weakness when one can be clearly identified and safely accessed. Radiosurgery is not performed in

  12. Effect of pore pressure buildup on slowness of rupture propagation

    NASA Astrophysics Data System (ADS)

    Ougier-Simonin, A.; Zhu, W.

    2015-12-01

    Pore fluid pressure is known to play an important role in brittle fracture initiation and propagation, yet the underlying mechanisms remain unclear. We conducted triaxial experiments on saturated porous sandstones to investigate effects of pore pressure buildup on the slowness of shear rupture propagation at different confining pressures. At low to intermediate confinements, rocks fail by brittle faulting, and pore pressure buildup causes a reduction in rock's shear strength but does not induce measurable differences in slip behavior. When the confinement is high enough to prohibit dynamic faulting, rocks fail in the brittle-ductile transitional regime. In the transitional regime, pore pressure buildup promotes slip instability on an otherwise stably sliding fracture. Compared to those observed in the brittle regime, the slip rate, stress drop, and energy dissipated during rupture propagation with concurrent pore pressure buildup in the transitional regime are distinctively different. When decreasing confining pressure instead, the slip behavior resembles the ones of the brittle regime, emphasizing how the observed slowness is related to excess pore pressure beyond the effective pressure phenomenon. Analysis of the mechanical data using existing theoretical models confirms these observations. Quantitative microstructural analyses reveal that increasing pore pressure lessens the dilatancy hardening during failure, thus enhances slip along the localized zone in the transitional regime. Our experimental results suggest that pore pressure buildup induces slow slip in the transitional regime, and slip rates along a shear fracture may vary considerably depending on effective stress states.

  13. Creep-rupture behavior of candidate Stirling engine alloys after long-term aging at 760 deg C in low-pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Titran, R. H.

    1984-01-01

    Nine candidate Stirling automotive engine alloys were aged at 760 C for 3500 hr in low pressure hydrogen or argon to determine the resulting effects on mechanical behavior. Candidate heater head tube alloys were CG-27, W545, 12RN72, INCONEL-718, and HS-188 while candidate cast cylinder-regenerator housing alloys were SA-F11, CRM-6D, XF-818, and HS-31. Aging per se is detrimental to the creep rupture and tensile strengths of the iron base alloys. The presence of hydrogen does not significantly contribute to strength degradation. Based percent highway driving cycle; CG-27 has adequate 3500 hr - 870 C creep rupture strength and SA-Fll, CRM-6D, and XF-818 have adequate 3500 hr - 775 C creep rupture strength.

  14. Spontaneous rupture of unscarred uterus in a primigravida with preterm prelabour rupture of membranes.

    PubMed

    Mourad, Wael Sayed; Bersano, Debbra J; Greenspan, Peter B; Harper, Diane Medved

    2015-06-08

    Intrapartum uterine rupture is a true obstetrical emergency. Uterine rupture is associated with severe maternal and fetal morbidity and mortality. It is rare in the unscarred uterus of a primigravida. A 23-year-old primigravida with an unscarred uterus was admitted with preterm prelabour rupture of membranes at 36(+4) weeks of gestation. Abnormal fetal heart monitoring, associated with acute onset of severe abdominopelvic pain, developed on admission. Rupture occurred prior to onset of regular uterine contractions and in the absence of any interventional oxytocin. The neonate had evidence of severe acidosis despite emergency caesarean delivery. This case highlights the importance of maintaining a high index of suspicion for uterine rupture, even in the unlikely setting of a primigravida with an unscarred uterus.

  15. Effect of MX type particles on creep strength of ferritic steel

    NASA Astrophysics Data System (ADS)

    Tamura, M.; Sakasegawa, H.; Kohyama, A.; Esaka, H.; Shinozuka, K.

    2003-09-01

    Creep rupture strength at 650 °C and microstructures of the plain ferritic steels with fine particles of the NaCl type (MX) were studied. Precipitation hardening by the fine MX type particles is more effective than solid solution hardening by tungsten. Excess precipitation of MX type particles relatively weakens the grain boundaries as compared with the matrix and, as a consequence, lowers the rupture strength. The equivalent obstacle spacing for mobile dislocations is calculated from the rupture data and is comparable to the interparticle distance observed by transmission electron microscopy. By controlling the interparticle distance of MX type particles with some adjustments of the chemical composition to meet the engineering requirements, it is feasible to develop a new alloy with high rupture strength at 650 °C which is superior to the conventional ferritic steels.

  16. The transverse mechanical behaviour of glass fibre reinforced plastics

    NASA Astrophysics Data System (ADS)

    Wells, Garry Michael

    The importance of transverse cracking in composites technology is highlighted by the use of classical lamination theory to predict the sequential damage process in cross-plied laminates. The literature on transverse fibre carposite behaviour is comprehensively reviewed, with particular emphasis on papers which present quantitative theoretical models. No work reviewed has measured the full range of mechanical properties on a single material necessary to allow a complete assessment of all the models of transverse failure. A resin system, based on epoxy/urethane blends, has been identified which allows production of high quality unidirectional composites with a systematic variation in flexibility. A preliminary experimental programme has identified those test specimens which can provide the necessary stress/strain and toughness properties of the range of flexibilised materials and thereby allow a validation of the theoretical models reviewed. In the preliminary experimental programme, transverse cracks are shown to extend with an increasing fracture toughness due to the formation of a 'tied zone' of fracture face bridging 'stringers' behind the crack tip. The influence of this effect on crack stability is discussed. By modelling the balance between fracture and strain energies, the equilibrium state of individual stringers is predicted. Direct observations of equilibrium stringer angles are seen to correspond with these predictions. A quite general model is developed which predicts, with reasonble accuracy, the observed increase of fracture toughness with crack extension and the geometry dependence of this increase. The literature models of stiffness, strength and failure strain are seen to display a dissappointing lack of agreement with the experimental results over the full range of material flexibilities. The influence of matrix Poisson constraint on these properties is discussed. Fracture toughness results indicate that very large critical defects control

  17. Dynamic rupture processes inferred from laboratory microearthquakes

    NASA Astrophysics Data System (ADS)

    Passelègue, François. X.; Schubnel, Alexandre; Nielsen, Stefan; Bhat, Harsha S.; Deldicque, Damien; Madariaga, Raúl

    2016-06-01

    We report macroscopic stick-slip events in saw-cut Westerly granite samples deformed under controlled upper crustal stress conditions in the laboratory. Experiments were conducted under triaxial loading (σ1>σ2=σ3) at confining pressures (σ3) ranging from 10 to 100 MPa. A high-frequency acoustic monitoring array recorded particle acceleration during macroscopic stick-slip events allowing us to estimate rupture speed. In addition, we record the stress drop dynamically and we show that the dynamic stress drop measured locally close to the fault plane is almost total in the breakdown zone (for normal stress >75 MPa), while the friction f recovers to values of f > 0.4 within only a few hundred microseconds. Enhanced dynamic weakening is observed to be linked to the melting of asperities which can be well explained by flash heating theory in agreement with our postmortem microstructural analysis. Relationships between initial state of stress, rupture velocities, stress drop, and energy budget suggest that at high normal stress (leading to supershear rupture velocities), the rupture processes are more dissipative. Our observations question the current dichotomy between the fracture energy and the frictional energy in terms of rupture processes. A power law scaling of the fracture energy with final slip is observed over 8 orders of magnitude in slip, from a few microns to tens of meters.

  18. Rupture of the round window membrane.

    PubMed

    Freeman, P

    1975-01-01

    Considerable interest has been displayed in sudden sensori-neural deafness in recent years, and especially since Blair Simmons postulated that this could be caused by mechanical disruption of the membranes in the inner ear. The literature concerning such reports is reviewed briefly and two cases of rupture of the round window membrane resulting from inner ear barotrauma are reported in detail. Both these cases were experienced divers who had had little difficulty in auto-inflation whilst diving. The first case had progressive sensori-neural deafness with mild vertigo, and tympanotomy revealed rupture of the round window membrane in both ears. These ruptures were repaired with plugs of fat, following which his hearing was restored. The second case developed marked vertigo following a dive and was thought to be suffering from decompression sickness. When the appropriate treatment did not help him, tympanotomy was performed and a rupture of the round membrane was found. This was plugged with fat with a most satisfactory result. Both of these cases had difficulty with autoinflation, and had been aware of such difficulties for some time. Nasal problems were responsible for this, and it is strongly recommended that all divers should have normal nasal function and that they should be educated in the technique of autoinflation, and, in particular, in the importance of avoiding forceful autoinflation at all times. A third case of rupture of the round membrane following an injury to the head is also reported.

  19. Rupture Process for Hayward Microearthquakes Inferred from Borehole Seismic Recordings

    NASA Astrophysics Data System (ADS)

    Taira, T.; Dreger, D. S.; Nadeau, R. M.

    2014-12-01

    The Hayward fault (HF) in the San Francisco Bay Area, California is one of the major strands of the San Andreas fault system, extending for about 70 km. Crustal deformation along the HF is characterized by a wide variety of fault slip behaviors from aseismic creep to stick-slip earthquake including a Mw ~6.8 earthquake in 1868. We here document the high-resolution imaging of the rupture models for the recent M 3+ HF earthquakes by making use of waveforms from the Hayward Fault Network (HFN). The HFN is an array of borehole seismic instrumentation and provides an unprecedented high-resolution coverage of the earthquake source study for HF earthquakes. Using the finite-source rupture inversion with an empirical Green's function approach, we find a variety of rupture propagations including subevents, directivity, and high stress drop. Our finite-source modeling reveals a complex slip distribution for the 2013 Mw 3.2 Orinda earthquake that is characterized by a patch of slip with a maximum slip of 4 cm concentrated near the hypocenter at about 6.6 km depth, with a large secondary patch of slip (peak slip of 2 cm) centered up-dip and southeast from the hypocenter at a distance of about 400 m away. The two subevents release 43% and 23% of the total seismic moment (6.7 x 1013 N m) and the inferred peak stress drops are 18 MPa and 10 MPa. The 2011 Mw 4.0 Berkeley and 2012 Mw 4.0 El Cerrito earthquakes are marked by high stress drop. The inferred peak and mean stress drops are about 130-165 MPa and 45 MPa, respectively, which suggests that there are locally high levels of the fault strength on the HF. Our finite-source modeling suggests that the radiation efficiency determined for these two earthquakes is very low (< 0.1) and implies that majority of energy is dissipated during the earthquake rupture process.

  20. Tensile and creep rupture properties of (16) uncoated and (2) coated engineering alloys at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Fritz, L. J.; Koster, W. P.

    1977-01-01

    Sixteen test materials were supplied by NASA-Lewis Research Center as wrought bar or cast remelt stock. The cast remelt stock was cast into test blanks with two such materials being also evaluated after Jocoat coating was applied. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, creep properties and creep rupture strength. Tests were conducted at temperatures applicable to the service temperature of the various alloys. This range extended from room temperature to 1000 C.

  1. Creep-rupture tests of internally pressurized Hastelloy-X tubes

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    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.

  2. PRV sizing for exchanger tube rupture

    SciTech Connect

    Wong, W.Y. )

    1992-02-01

    This paper reports on heat exchanger tube ruptures which is one of the common over-pressure scenarios of pressure relief valve (PRV) design. ASME Code VIII-1 indicates that heat exchangers shall be protected with a relieving device of sufficient capacity to avoid over-pressure in case of an internal failure. But it does not provide any guidance on how to size a PRV and how to define the required relief load. API RP 520 Part I and API RP 521 do offer some guidelines for heat exchanger tube rupture in PRV design, but they are too general to be used to perform a detailed calculation or to do a relief system analysis. Furthermore, API 520's two-phase flow calculation concepts contradict its own assumptions, which makes its design approach infeasible. A detailed PRV design procedure for heat exchanger tube rupture will be discussed.

  3. Spontaneous rupture of the common bile duct.

    PubMed

    Kyzer, S; Bayer, I; Chaimoff, C

    1986-01-01

    Spontaneous rupture of the common bile duct in adults is very rare. The authors report only the 14th case in the Western literature. A 25-year-old woman had signs of peritonitis suggestive of a perforated appendix, but at operation the appendix appeared normal and a large amount of bile was found in the peritoneal cavity. A 2-mm tear was found on the anterior wall of the common bile duct. The patient recovered without complications after T-tube drainage and cholecystectomy. In this patient none of the factors thought to cause spontaneous rupture of the common bile duct were present, so the authors conclude that the case may be classified as idiopathic spontaneous rupture of the common bile duct. PMID:3940592

  4. Postmyomectomic Uterine Rupture Despite Cesarean Section.

    PubMed

    Kacperczyk, Joanna; Bartnik, Paweł; Romejko-Wolniewicz, Ewa; Dobrowolska-Redo, Agnieszka

    2016-03-01

    Uterine fibroids (leiomyomas) are benign smooth muscle tumors of the uterus. Fibroids can develop anywhere within the muscular wall. Leiomyomas may be associated with infertility. Laparoscopic myomectomy is often used to remove symptomatic intramural or subserosal fibroids. Advantages of the procedure include short recovery time and minimal perioperative morbidity. At the same time, the multilayer suture technique is more complicated during laparoscopy. A rare but serious complication of laparoscopic myomectomies is uterine rupture. A brief review of the literature and a clinical example of a 33-year-old woman with history of infertility, laparoscopic myomectomies and uterine rupture followed by peripartum hemorrhage is presented. The treatment of leiomyomas is a challenge not only because of possible recurrence but also due to long-term consequences following successful myomectomy. Management of patients with uterine scars should include careful planning of the route of delivery, as the risk of rupture may be increased. PMID:26976991

  5. Augmented repair of acute Achilles tendon ruptures.

    PubMed

    Zell, R A; Santoro, V M

    2000-06-01

    Twenty-five patients who had an acute Achilles tendon rupture were managed with an augmented repair using the gastrocnemius-soleus fascia. All patients healed their repair and there were no re-ruptures. There was one infection. Augmented repair allowed early functional recovery as evidenced by full ankle motion by four to eight weeks, full unassisted weight bearing by three weeks, cessation of braces by four weeks, and return to work by one to six weeks post-operatively. Augmentation adds a sufficient amount of collagen to allow early range of motion and weight bearing without re-rupture. Disadvantages included a long incision, soft tissue prominence, one infection, and sural nerve injury.

  6. Transverse angular momentum of photons

    SciTech Connect

    Aiello, Andrea

    2010-05-15

    We develop the quantum theory of transverse angular momentum of light beams. The theory applies to paraxial and quasiparaxial photon beams in vacuum and reproduces the known results for classical beams when applied to coherent states of the field. Both the Poynting vector, alias the linear momentum, and the angular-momentum quantum operators of a light beam are calculated including contributions from first-order transverse derivatives. This permits a correct description of the energy flow in the beam and the natural emergence of both the spin and the angular momentum of the photons. We show that for collimated beams of light, orbital angular-momentum operators do not satisfy the standard commutation rules. Finally, we discuss the application of our theory to some concrete cases.

  7. Spontaneous Achilles tendon rupture in alkaptonuria

    PubMed Central

    Alajoulin, Omar A.; Alsbou, Mohammed S.; Ja’afreh, Somayya O.; Kalbouneh, Heba M.

    2015-01-01

    Alkaptonuria (AKU) is a rare inborn metabolic disease characterized by accumulation of homogentisic acid (HGA). Excretion of HGA in urine causes darkening of urine and its deposition in connective tissues causes dark pigmentation (ochronosis), early degeneration of articular cartilage, weakening of the tendons, and subsequent rupture. In this case report, we present a rare case of a patient presented with unilateral spontaneous rupture of Achilles tendon due to AKU. The patient developed most of the orthopedic manifestations of the disease earlier than typical presentations. Alkaptonuria patients should avoid strenuous exercises and foot straining especially in patients developing early orthopedic manifestations. PMID:26620992

  8. Thoracic outlet syndrome following breast implant rupture.

    PubMed

    Mistry, Raakhi; Caplash, Yugesh; Giri, Pratyush; Kearney, Daniel; Wagstaff, Marcus

    2015-03-01

    We present a patient with bilateral breast implant rupture who developed severe locoregional silicone granulomatous lymphadenopathy. Poly Implant Prothese silicone implants had been used for bilateral breast augmentation 5 years prior. Extracapsular implant rupture and bilateral axillary lymphadenopathy indicated explantation, capsulectomy, and selective lymph node excision. Histology demonstrated silicone lymphadenopathy with no evidence of malignancy. Over the subsequent 12 months, she developed progressive locoregional lymphadenopathy involving bilateral cervical, axillary, and internal mammary groups, resulting in bilateral thoracic outlet syndrome. We report the unusual presentation, progression, and the ultimate surgical management of this patient. PMID:25878942

  9. Thoracic Outlet Syndrome Following Breast Implant Rupture

    PubMed Central

    Caplash, Yugesh; Giri, Pratyush; Kearney, Daniel; Wagstaff, Marcus

    2015-01-01

    Summary: We present a patient with bilateral breast implant rupture who developed severe locoregional silicone granulomatous lymphadenopathy. Poly Implant Prothese silicone implants had been used for bilateral breast augmentation 5 years prior. Extracapsular implant rupture and bilateral axillary lymphadenopathy indicated explantation, capsulectomy, and selective lymph node excision. Histology demonstrated silicone lymphadenopathy with no evidence of malignancy. Over the subsequent 12 months, she developed progressive locoregional lymphadenopathy involving bilateral cervical, axillary, and internal mammary groups, resulting in bilateral thoracic outlet syndrome. We report the unusual presentation, progression, and the ultimate surgical management of this patient. PMID:25878942

  10. Tendon ruptures: mallet, flexor digitorum profundus.

    PubMed

    Yeh, Peter C; Shin, Steven S

    2012-08-01

    Mallet injuries are the most common closed tendon injury in the athlete. Flexor digitorum profundus ruptures are rare in baseball, but are common injuries in contact sports. The diagnosis for each condition is based on clinical examination, although radiographs should be evaluated for a possible bony component. Treatment for mallet injury depends on the athlete's goals of competition and understanding of the consequences of any treatment chosen. Gripping, throwing, and catching would be restricted or impossible with the injured finger immobilized. Treatment of FDP ruptures is almost always surgical and requires reattachment of the torn tendon to the distal phalanx.

  11. Patellar tendon rupture: an ultrasound case report.

    PubMed

    Berg, Kenneth; Peck, Jeff; Boulger, Creagh; Bahner, David P

    2013-01-01

    This article discusses a case in which ultrasound was the primary modality for diagnosis of traumatic patellar tendon rupture. Traditionally, this diagnosis has been made using MRI. This case highlights the growing need for emergency medicine physicians to become facile with bedside ultrasound and its indications as a supplement to traditional musculoskeletal examination. Normal and pathological patellar tendon examinations with ultrasound are discussed in detail. Furthermore, the advantages of ultrasound over the more traditional imaging modalities of x-ray and MRI in cases where tendon rupture is suspected are discussed.

  12. Effect of stress state on slow rupture propagation in synthetic fault gouges

    NASA Astrophysics Data System (ADS)

    Hirauchi, Ken-ichi; Muto, Jun

    2015-02-01

    Slow slip events (SSEs) in subduction zones are known to proceed so sluggishly that the associated slow ruptures do not generate any detectable radiating seismic waves. Moreover, they propagate at speeds at least four orders of magnitude slower than regular earthquakes. However, the underlying physics of slow slip generation has yet to be understood. Here, we carry out laboratory studies of unstable slip along simulated fault zones of lizardite/chrysotile (liz/ctl) and antigorite (i.e., low- and high-temperature serpentine phases, respectively) and olivine, under varying conditions of normal stress, with the aim of better understanding the influence of stress state on the process of slow rupture along the plate interface. During a single unstable slip, we clearly observe a slow rupture phase that is often followed by an unstable, high-speed rupture. We find that lower fault-zone friction coefficients (μ values from 0.7 down to 0.5) lead to increasing degree of the slow rupture mode, and also that the slow rupture velocities ( V r = 0.07 to 5.43 m/s) are largely consistent with those of short-term SSEs observed in nature. Our findings suggest that the generation of SSEs is facilitated by conditions of low normal stress and low fault-zone strength along the plate interface, which may be weakened by metamorphic reactions that result in the production of hydrous phases (e.g., serpentine) and/or the direct involvement of fluid itself, leading to a reduction in effective normal stress.

  13. Transverse spin effects at COMPASS

    SciTech Connect

    Pesaro, G.

    2009-03-23

    The COMPASS experiment at the CERN SPS has a broad physics program focused on the nucleon spin structure and on hadron spectroscopy, using both muon and hadron beams. One of the main objectives for the spin program with the muon beam is the measurement of transverse spin effects in semi inclusive deep inelastic scattering. A longitudinally polarized 160 GeV/c muon beam is impinging on a transversely polarized target: from 2002 to 2004 a {sup 6}LiD(deuteron) target has been used, while during 2007 data taking a NH{sub 3}(proton) target was put in place. All measured transverse asymmetries on deuteron have been found to be small, and compatible with zero, within the few percent statistical errors. These results, which are currently used as input for global fits, can be interpreted as cancellation between u and d quark contribution in the deuteron. The first results for the Collins and Sivers asymmetries for charged hadrons from the 2007 proton COMPASS data are also presented and discussed.

  14. Evaluation of Transverse Tensile Stress Characteristics of GdBCO Coated Conductors

    NASA Astrophysics Data System (ADS)

    Sato, H.; Nakamura, N.; Fujita, S.; Daibo, M.; Iijima, Y.

    Recently, GdBCO coated conductor (CC) coils for high field magnets are investigated for practical use. GdBCO CC coils are subjected to longitudinal and transverse tensile stresses in their operation, so there is some research for mechanical properties of the GdBCO CCs in the recent years. Fujikura has also researched mechanical properties, for example, tensile or delamination strength, of the GdBCO CCs. In this report, we investigated pin-pull delamination test in Liquid nitrogen (LN2) to research mechanical delamination and critical current (Ic) degradation strength. We found out mechanical delamination strength is corresponding to Ic degradation strength. In addition, we experiment repeated transverse tensile stress on GdBCO CCs in LN2, most of the samples have more than 50 times at 50 MPa, which corresponds to single delamination strength, and there is no Ic degradation before mechanical delamination.

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

    NASA Astrophysics Data System (ADS)

    Tarasov, Boris G.

    2014-05-01

    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 ‘domino-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.

  16. Triggered reverse fault and earthquake due to crustal unloading, northwest Transverse Ranges, California.

    USGS Publications Warehouse

    Yerkes, R.F.; Ellsworth, W.L.; Tinsley, J.C.

    1983-01-01

    A reverse-right-oblique surface rupture, associated with a ML 2.5 earthquake, formed in a diatomite quarry near Lompoc, California, in the northwesternmost Transverse Ranges on April 7, 1981. The 575-m-long narrow zone of ruptures formed in clay interbeds in diatomite and diatomaceous shale of the Neogene Monterey Formation. The ruptures parallel bedding, dip 39o-59oS, and trend about N84oE on the north limb of an open symmetrical syncline. Maximum net slip was 25 cm; maximum reverse dip slip was 23 cm, maximum right-lateral strike slip was about 9 cm, and average net slip was about 12 cm. The seismic moment of the earthquake is estimated at 1 to 2 X 1018 dyne/cm and the static stress drop at about 3 bar. The removal of an average of about 44 m of diatomite resulted in an average load reduction of about 5 bar, which decreased the normal stress by about 3.5 bar and increased the shear stress on the tilted bedding plane by about 2 bar. The April 7, 1981, event was a very shallow bedding-plane rupture, apparently triggered by crustal unloading. -Authors

  17. QCD Evolution of Helicity and Transversity TMDs

    SciTech Connect

    Prokudin, Alexei

    2014-01-01

    We examine the QCD evolution of the helicity and transversity parton distribution functions when including also their dependence on transverse momentum. Using an appropriate definition of these polarized transverse momentum distributions (TMDs), we describe their dependence on the factorization scale and rapidity cutoff, which is essential for phenomenological applications.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

  19. Validation of the rupture properties of the 2001 Kunlun, China (Ms = 8.1), earthquake from seismological and geological observations

    USGS Publications Warehouse

    Wen, Y.-Y.; Ma, K.-F.; Song, T.R.-A.; Mooney, W.D.

    2009-01-01

    We determine the finite-fault slip distribution of the 2001 Kunlun earthquake (Ms = 8.1) by inverting teleseismic waveforms, as constrained by geological and remote sensing field observations. The spatial slip distribution along the 400-km-long fault was divided into five segments in accordance with geological observations. Forward modelling of regional surface waves was performed to estimate the variation of the speed of rupture propagation during faulting. For our modelling, the regional 1-D velocity structure was carefully constructed for each of six regional seismic stations using three events with magnitudes of 5.1-5.4 distributed along the ruptured portion of the Kunlun fault. Our result shows that the average rupture velocity is about 3.6 km s-1, consistent with teleseismic long period wave modelling. The initial rupture was almost purely strike-slip with a rupture velocity of 1.9 km s-1, increasing to 3.5 km s-1 in the second fault segment, and reaching a rupture velocity of about 6 km s-1 in the third segment and the fourth segment, where the maximum surface offset, with a broad fault zone, was observed. The rupture velocity decelerated to a value of 3.3 km s-1 in the fifth and final segment. Coseismic slip on the fault was concentrated between the surface and a depth of about 10 km. We infer that significant variations in rupture velocity and the observed fault segmentation are indicative of variations in strength along the interface of the Kunlun fault, as well as variations in fault geometry. ?? 2009 The Authors Journal compilation ?? 2009 RAS.

  20. Primary gastric rupture in 47 horses (1995–2011)

    PubMed Central

    Winfield, Laramie S.; Dechant, Julie E.

    2015-01-01

    The purpose of this retrospective case-control study was to identify factors associated with primary gastric rupture and to investigate if there were differences between etiologies of primary gastric rupture. Compared to the general colic population, Quarter horses were under-represented and Friesians and draft breeds were over-represented in 47 cases of primary gastric ruptures. Horses with primary gastric rupture typically presented with severe clinical and clinicopathological derangements. There were 24 idiopathic gastric ruptures, 20 gastric impaction associated ruptures, and 3 perforating gastric ulcers. Thoroughbred horses were over-represented in the idiopathic gastric rupture group compared to other breeds and etiologies. This study suggests the presence of important breed predispositions for development of gastric rupture. Further study is necessary to identify if these predispositions are associated with management factors or breed-specific disorders. PMID:26345205

  1. [Popliteal cyst rupture due to unusual physical stress].

    PubMed

    Romem, Ayal; Shimony, Avi; Horowitz, Sharon; Horowitz, Jacob

    2007-09-01

    Popliteal cyst rupture is a known phenomenon following strenuous labor or sport activity. We present a case in which popliteal cyst rupture followed an unusual strenuous physical activity--devoted prayer during the holy month of the Ramadan. PMID:17969298

  2. Bilateral infrapatellar tendon rupture in a patient with jumper's knee.

    PubMed

    Rosenberg, J M; Whitaker, J H

    1991-01-01

    This is the fourth case report of bilateral infrapatellar tendon rupture as a result of indirect trauma in a patient without systemic disease. This is the only report we have found of jumper's knee leading to simultaneous infrapatellar tendon ruptures.

  3. An Uncommon Presentation of Breast Implant Rupture

    PubMed Central

    Watson, David I.; Dean, Nicola R.

    2016-01-01

    Summary: Late periprosthetic seroma has lately been concerning for breast implant-associated anaplastic large cell lymphoma. The authors present an uncommon presentation of breast implant rupture with a seroma and skin rash forming 2 years after insertion of the implant. PMID:27579243

  4. Gastric rupture secondary to successful Heimlich manoeuvre.

    PubMed Central

    Majumdar, A.; Sedman, P. C.

    1998-01-01

    A fatal case of gastric rupture following the Heimlich manoeuvre is reported. This life-threatening complication has only been reported previously in seven patients with a high mortality rate. All patients should be assessed immediately following this manoeuvre for any potentially life-threatening complications. Images Figure PMID:10211358

  5. [Splenic rupture--a skateboard accident].

    PubMed

    Kruse, P

    1990-03-01

    A 13-year-old boy presented with persisting abdominal pain after a skateboard accident. Primary clinical and laboratory findings disclosed no signs of intra abdominal bleeding. Ultrasound scanning indicated rupture of the spleen which was confirmed by acute exploratory laparotomy.

  6. Star polymers rupture induced by constant forces

    NASA Astrophysics Data System (ADS)

    García, N. A.; Febbo, M.; Vega, D. A.; Milchev, A.

    2014-10-01

    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.

  7. D-Zero Cryostat Supplemental Rupture Disc

    SciTech Connect

    Mulholland, G.T.; /Fermilab

    1987-08-03

    The common relief and rupture disc vent line requires a double disc assembly with vented interspace for accurate disc burst pressures. The first disc must take pump and purge vacuum loading, but be set to operate at 110% of the MAWP, 18.3 psig (ASME code). The available solution is 18.3 psig with a burst tolerance of +/- psig. The interspace should be locally vented by a flow limiting vent valve to decouple the vent line backpressure from the vessel rupture disc. The second disc must take the worst case vent line backpressure, the steady state value found in D-Zero engineering note 3740.000-EN-63 with all three cryostats simultaneously venting at the fire condition into the 4-inch x 6-inch and 6-inch x 8-inch sections. This value is less than 2 psid. The maximum rupture value for the second disc must be less than the minimum rupture value for the first disc less 2 psid i.e. < 16.3.

  8. Fatigue crack propagation analysis of plaque rupture.

    PubMed

    Pei, Xuan; Wu, Baijian; Li, Zhi-Yong

    2013-10-01

    Rupture of atheromatous plaque is the major cause of stroke or heart attack. Considering that the cardiovascular system is a classic fatigue environment, plaque rupture was treated as a chronic fatigue crack growth process in this study. Fracture mechanics theory was introduced to describe the stress status at the crack tip and Paris' law was used to calculate the crack growth rate. The effect of anatomical variation of an idealized plaque cross-section model was investigated. The crack initiation was considered to be either at the maximum circumferential stress location or at any other possible locations around the lumen. Although the crack automatically initialized at the maximum circumferential stress location usually propagated faster than others, it was not necessarily the most critical location where the fatigue life reached its minimum. We found that the fatigue life was minimum for cracks initialized in the following three regions: the midcap zone, the shoulder zone, and the backside zone. The anatomical variation has a significant influence on the fatigue life. Either a decrease in cap thickness or an increase in lipid pool size resulted in a significant decrease in fatigue life. Comparing to the previously used stress analysis, this fatigue model provides some possible explanations of plaque rupture at a low stress level in a pulsatile cardiovascular environment, and the method proposed here may be useful for further investigation of the mechanism of plaque rupture based on in vivo patient data.

  9. An Uncommon Presentation of Breast Implant Rupture.

    PubMed

    Koh, Eugene; Watson, David I; Dean, Nicola R

    2016-05-01

    Late periprosthetic seroma has lately been concerning for breast implant-associated anaplastic large cell lymphoma. The authors present an uncommon presentation of breast implant rupture with a seroma and skin rash forming 2 years after insertion of the implant. PMID:27579243

  10. Pancreatic pseudocyst rupture into the portal vein.

    PubMed

    Dawson, Brian C; Kasa, David; Mazer, Mark A

    2009-07-01

    A patient with a pancreatic pseudocyst rupture into the portal vein with a resultant noninfectious systemic inflammatory response syndrome and subsequent portal vein thrombosis diagnosed by computed tomography and ultrasonography is reported. A review of the existing English literature on this rare complication is also provided. PMID:19561436

  11. Star polymers rupture induced by constant forces.

    PubMed

    García, N A; Febbo, M; Vega, D A; Milchev, A

    2014-10-28

    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

  12. Primary obstructive megaureter with ruptured kidney.

    PubMed

    Chung, Shiu-Dong; Sun, Hsu-Dong; Yang, Den-Kai; Liao, Chun-Hou

    2009-01-01

    A 17-year-old boy presented to the emergency department for severe left flank pain and gross hematuria 1 hour after playing basketball without significant collision. Laboratory tests showed normal renal function and massive hematuria. Abdominal computed tomography scan disclosed a primary megaureter with ruptured kidney. We successfully treated him with ureteral stenting followed by endoscopic ureterotomy and ureteroneocystostomy.

  13. Single-ion anisotropy and transverse magnetization in the frustrated gadolinium pyrochlores

    NASA Astrophysics Data System (ADS)

    Glazkov, V. N.; Zhitomirsky, M.; Smirnov, A. I.; Marin, C.; Sanchez, J.-P.; Forget, A.; Colson, D.; Bonville, P.

    2007-04-01

    A single-ion anisotropy of the planar type is found in the pyrochlore antiferromagnet oxides Gd2M2O7 (M = Ti,Sn); its strength is comparable with the strength of the exchange coupling. Models considering the effects of the planar anisotropy predict the appearance of a transverse magnetization in an applied magnetic field. A detailed experimental study of Gd2Ti2O7 single crystals reveals that a transverse magnetization is really present at low temperatures. The magnetic phase diagram of Gd2Ti2O7 is refined.

  14. Rupture to the Trench in Dynamic Models of the Tohoku-Oki Earthquake

    NASA Astrophysics Data System (ADS)

    Kozdon, J. E.; Dunham, E. M.

    2011-12-01

    The devastating tsunami caused by the 11 March 2011 Tohoku-Oki earthquake was much larger than conventional thinking would suggest. One of the primary reasons for the large tsunami was the ~5-10 m of seafloor uplift resulting from the inferred ~60 m of slip that extended to the trench axis along the base of the accretionary prism. However, the prism is believed to store negligible strain energy and the fault along its base is thought to be frictionally stable. Both factors suggest this region is not capable of sustaining rupture, and that earthquakes should stop well before the trench. Dynamic rupture simulations, which solve for rupture history and elastodynamic response in a fully consistent manner, provide a powerful tool for probing this seeming inconsistency. We have developed a 2-D model based on the detailed structure of the Japan trench. The model is comprised of multiple, irregularly shaped material blocks including the accretionary prism, oceanic crust layers, and mantle and crustal blocks. The fault response is modeled using rate-and-state friction. Inelastic deformation of the off-fault material, particularly in the low-strength prism, is captured using Drucker-Prager plasticity. The governing equations are solved with a provably stable, high-order finite difference method that handles complex geometries through the use of coordinate transforms. Both the initial stresses and frictional parameters vary with depth. Preliminary simulations suggest that the rupture can reach the trench even if the fault interface along the base of the accretionary prism is frictionally stable. Seismic waves released during updip rupture propagation on the shallowly dipping fault reflect off the seafloor back to the fault. These waves carry stress perturbations that unclamp the fault and transiently reduce fault strength. We also highlight the important role of material contrast across the fault. At sufficient depth, the oceanic crust becomes more compliant than the

  15. Transverse Force on Quarks in DIS

    SciTech Connect

    Burkardt, Matthias

    2009-01-01

    The $x^2$-moment of the twist-3 polarized parton distribution $g_2(x)$ is related to the transverse force acting on the active quark in deep-inelastic scattering off a transversely polarized nucleon immediately after it has absorbed the virtual photon. Lattice calculations of the corresponding matrix element as well as experimental measurements of $g_2(x)$ are used to estimate sign and magnitude of this force. Similarly, the $x^2$-moment of the chirally odd twist-3 unpolarized parton distribution $e(x)$ can be related to the transverse force experienced by a transversely polarized quark ejected from a transversely polarized nucleon.

  16. Transverse Momentum Dependent Distributions in Hard Scattering

    SciTech Connect

    Alexie Prokudin

    2011-05-01

    Transverse Momentum Dependent Distributions (TMDs) describe the spin structure of the proton. At leading twist spin structure of spin-1/2 hadron can be described by 8 TMDs. TMDs reveal three-dimensional distribution of partons inside polarised nucleon. Experimentally these functions can be studied in polarised experiments using Spin Asymmetries in particular Single Spin Asymmetries (SSAs). We discuss transversity that measures distribution of transversely polarised quarks in a transversely polarised nucleon and Sivers distribution function that describes distribution of unpolarised quarks in a transversely polarised nucleon.

  17. [Simultaneous rupture of a patellar tendon and contralateral quadriceps tendon].

    PubMed

    Horas, U; Ernst, S; Meyer, C; Halbsguth, A; Herbst, U

    2006-09-01

    The simultaneous bilateral rupture of the quadriceps tendon is a rare injury; only occasional reports exist about the bilateral simultaneous rupture of the patellar tendon. Degenerative changes of the tendon due to drugs or diseases lead to the rupture. We describe two cases of simultaneous rupture of the patellar and contralateral quadriceps tendons; only one patient had special risks. We report the management of therapy and the functional results using the Lysholm score and Knee Rating Scale.

  18. Suppression of microbunching instability via a transverse gradient undulator

    NASA Astrophysics Data System (ADS)

    Feng, Chao; Huang, Dazhang; Deng, Haixiao; Gu, Qiang; Zhao, Zhentang

    2015-07-01

    The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with a transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by varying the strength of the undulator magnetic field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an x-ray free-electron laser.

  19. Propagation of optical beams in two transverse gradient index media

    NASA Astrophysics Data System (ADS)

    Martín-Ruiz, A.; Martín-Heredia, J.; Ruiz-Ochoa, L. A.; Chan-López, E.

    2016-05-01

    We investigate the propagation of optical beams in two gradient index inhomogeneous media. The Green's function for paraxial propagation in an inhomogeneous medium is derived as a Feynman path integral involving summation over real rays. We use a simple method based on discontinuous functions, which is similar to that used in General Relativity when studying metric discontinuities across an hypersurface, to study the propagation in two transverse refractive index gradients which are coupled in the propagation direction. We show that this method is consistent with the geometric-optics ray theory, and then with the definition of the coupled Green's function. The propagation of Gaussian beams in two homogeneous media with different refractive indices is analyzed. We also study the propagation of Airy beams in two media with different linear transverse refractive index gradients. We demonstrate that by controlling the gradient strength of the media it is possible to reduce to zero their acceleration, yielding an Airy beam that propagates linearly.

  20. Earthquake Source Parameters Relationships from 3D Rough Fault Dynamic Rupture

    NASA Astrophysics Data System (ADS)

    Yao, Q.; Day, S. M.; Shi, Z.

    2015-12-01

    Fault surface roughness has a strong influence on the distribution of stress around the fault, and affects the dynamics of the earthquake process. In particular, roughness influences the distribution of the parameters conventionally used to describe fault slip in, for example, kinematic modeling of strong ground motion. We explore the effect of the fault roughness on earthquake source parameters through the statistical analysis of a large suite of 3D rupture simulations. We have built a database of more than 1000 simulated dynamic ruptures based on different rough fault profiles and relative-strength (S) ratios, and have quantitatively analyzed the correlation between earthquake source parameter pairs.. In the subshear propagation-speed regime, we find the following relationships: (1) Rise time, total slip and peak slip rate each decrease with increasing roughness. (2) Rupture velocity is weakly positively related to slip, and the relationship is stronger with increasing roughness. We also explore how peak slip rate, rise time and different pairs of source parameters correlations are affected by fault roughness. This work may give useful guidance for use in kinematic rupture-source generators and help improve methods for ground strong motion prediction.

  1. A new method of repair for quadriceps tendon ruptures. A case report.

    PubMed

    Maniscalco, P; Bertone, C; Rivera, F; Bocchi, L

    2000-09-01

    Rupture of the quadriceps tendon is an uncommon injury observed predominantly in subjects over 40 years old. Multiple surgical techniques have been employed to repair fresh and neglected ruptures; methods that make use of allograft and augmentation with tissues harvested from around the knee have been reported. We describe a case of surgical repair of a tendon-bone junction rupture in a 64-year-old patient by use of suture anchors to attach the tendon to bone and improve fixation of the soft tissue elements. Clinical diagnosis of rupture was confirmed radiographically and echographically. Surgical repair was performed within 24 hours of injury. Active movement of the knee started after 3 weeks and the patient was permitted to walk without weight-bearing with a knee cage. Three weeks later, he was permitted to walk with full weight-bearing unassisted by crutches; the knee cage was removed 6 weeks after surgery. At his most recent follow-up 24 months postoperative, quadriceps strength was equal to that of the controlateral knee and the patient has returned to sports and daily activities. The surgical method presented here provides a suture of the tendon ends without putting excess stress on the suture line during the period of early knee mobilization. Advantages over other techniques include reduced operative time, easy access to the implantation site, and better resistance of the suture material: the patient is thus able to initiate physical therapy earlier and more aggressively.

  2. Quantification of Ground Motion Reductions by Fault Zone Plasticity with 3D Spontaneous Rupture Simulations

    NASA Astrophysics Data System (ADS)

    Roten, D.; Olsen, K. B.; Cui, Y.; Day, S. M.

    2015-12-01

    We explore the effects of fault zone nonlinearity on peak ground velocities (PGVs) by simulating a suite of surface rupturing earthquakes in a visco-plastic medium. Our simulations, performed with the AWP-ODC 3D finite difference code, cover magnitudes from 6.5 to 8.0, with several realizations of the stochastic stress drop for a given magnitude. We test three different models of rock strength, with friction angles and cohesions based on criteria which are frequently applied to fractured rock masses in civil engineering and mining. We use a minimum shear-wave velocity of 500 m/s and a maximum frequency of 1 Hz. In rupture scenarios with average stress drop (~3.5 MPa), plastic yielding reduces near-fault PGVs by 15 to 30% in pre-fractured, low-strength rock, but less than 1% in massive, high quality rock. These reductions are almost insensitive to the scenario earthquake magnitude. In the case of high stress drop (~7 MPa), however, plasticity reduces near-fault PGVs by 38 to 45% in rocks of low strength and by 5 to 15% in rocks of high strength. Because plasticity reduces slip rates and static slip near the surface, these effects can partially be captured by defining a shallow velocity-strengthening layer. We also perform a dynamic nonlinear simulation of a high stress drop M 7.8 earthquake rupturing the southern San Andreas fault along 250 km from Indio to Lake Hughes. With respect to the viscoelastic solution (a), nonlinearity in the fault damage zone and in near-surface deposits would reduce long-period (> 1 s) peak ground velocities in the Los Angeles basin by 15-50% (b), depending on the strength of crustal rocks and shallow sediments. These simulation results suggest that nonlinear effects may be relevant even at long periods, especially for earthquakes with high stress drop.

  3. Spin resonance strength calculation through single particle tracking for RHIC

    SciTech Connect

    Luo, Y.; Dutheil, Y.; Huang, H.; Meot, F.; Ranjbar, V.

    2015-05-03

    The strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with the code DEPOL, which numerically integrates through the ring based on an analytical approximate formula. In this article, we test a new way to calculate the spin resonance strengths by performing Fourier transformation to the actual transverse magnetic fields seen by a single particle traveling through the ring. Comparison of calculated spin resonance strengths is made between this method and DEPOL.

  4. Ruptured rectal duplication with urogenital abnormality: Unusual presentation

    PubMed Central

    Solanki, Shailesh; Babu, M Narendra; Jadhav, Vinay; Shankar, Gowri; Santhanakrishnan, Ramesh

    2015-01-01

    Rectal duplication (RD) accounts for 5% of alimentary tract duplication. A varied presentation and associated anomalies have been described in the literature. Antenatal rupture of the RD is very rare. We present an unusual case of a ruptured RD associated with urogenital abnormalities in newborn male. We are discussing diagnosis, embryology, management and literature review of ruptured RD. PMID:25552833

  5. 46 CFR 153.1500 - Venting system rupture disks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....1500 Venting system rupture disks. The master shall ensure that a relief valve exposed to a cargo after the failure of a rupture disk or breaking pin is cleaned and operates properly before the next cargo... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system rupture disks. 153.1500 Section...

  6. 46 CFR 153.1500 - Venting system rupture disks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ....1500 Venting system rupture disks. The master shall ensure that a relief valve exposed to a cargo after the failure of a rupture disk or breaking pin is cleaned and operates properly before the next cargo... 46 Shipping 5 2012-10-01 2012-10-01 false Venting system rupture disks. 153.1500 Section...

  7. 46 CFR 153.1500 - Venting system rupture disks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....1500 Venting system rupture disks. The master shall ensure that a relief valve exposed to a cargo after the failure of a rupture disk or breaking pin is cleaned and operates properly before the next cargo... 46 Shipping 5 2011-10-01 2011-10-01 false Venting system rupture disks. 153.1500 Section...

  8. 46 CFR 153.1500 - Venting system rupture disks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....1500 Venting system rupture disks. The master shall ensure that a relief valve exposed to a cargo after the failure of a rupture disk or breaking pin is cleaned and operates properly before the next cargo... 46 Shipping 5 2014-10-01 2014-10-01 false Venting system rupture disks. 153.1500 Section...

  9. 46 CFR 153.1500 - Venting system rupture disks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....1500 Venting system rupture disks. The master shall ensure that a relief valve exposed to a cargo after the failure of a rupture disk or breaking pin is cleaned and operates properly before the next cargo... 46 Shipping 5 2013-10-01 2013-10-01 false Venting system rupture disks. 153.1500 Section...

  10. Colloidal Instability Fosters Agglomeration of Subvisible Particles Created by Rupture of Gels of a Monoclonal Antibody Formed at Silicone Oil-Water Interfaces.

    PubMed

    Mehta, Shyam B; Carpenter, John F; Randolph, Theodore W

    2016-08-01

    In this study, we investigated the effect of ionic strength (1.25-231 mM) on viscoelastic interfacial gels formed by a monoclonal antibody at silicone oil-water interfaces, and the formation of subvisible particles due to rupture of these gels. Rates of gel formation and their elastic moduli did not vary significantly with ionic strength. Likewise, during gel rupture no significant effects of ionic strength were observed on particle formation and aggregation as detected by microflow imaging, resonance mass measurement, and size exclusion chromatography. Subvisible particles formed by mechanical rupturing of the gels agglomerated over time, even during quiescent incubation, due to the colloidal instability of the particles. PMID:27422087

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

  12. Higher levels of collagen and facilitated healing protect against ventricular rupture following myocardial infarction.

    PubMed

    Fang, Lu; Gao, Xiao-Ming; Samuel, Chrishan S; Su, Yidan; Lim, Yean Leng; Dart, Anthony M; Du, Xiao-Jun

    2008-08-01

    The mechanism of cardiac rupture after MI (myocardial infarction) is not fully understood. Rupture has not been reported in most laboratory species, including the rat, but does occur in mice. We have reported previously that beta2-TG mice (transgenic mice with cardiac-restricted overexpression of beta2-adrenergic receptors) had a lower incidence of rupture compared with NTG (non-transgenic) littermates. We hypothesized that the difference in the incidence of rupture between rodents and specific mouse strains is due to the difference in collagen content following MI. In the present study, we compared the difference in matrix remodelling post-MI between beta2-TG and NTG mice and between mice and rats. MI was induced by ligation of the left main coronary artery. Following MI, tensile strength, insoluble and soluble collagen content and gelatinase expression were determined in the infarcted and non-infarcted myocardium. Better preserved tensile strength measured as TTR [tension-to-rupture; 88+/-14 and 58+/-3% of the respective sham group values for beta2-TG compared with NTG mice (P<0.05); 108+/-7 and 32+/-4% of the respective sham group values for rats compared with 129sv mice (P<0.01)] and less severe acute infarct expansion after MI were found in rats compared with mice or in beta2-TG compared with NTG mice. These differences were associated with a higher content of pre-existing fibril collagen in the normal myocardium of beta2-TG compared with NTG mice (1.6-fold) or rats compared with 129sv mice (2-fold) and an accelerated fibrotic healing in the infarcted myocardium. Additionally, a less pronounced increase in MMP-9 (matrix metalloproteinase-9) activity was observed in the infarcted myocardium of rats compared with 129sv mice. We conclude that a higher collagen level is associated with facilitated fibrotic healing of an infarct and preserves the tensile strength of infarcted myocardium, thereby preventing cardiac rupture and acute ventricular remodelling.

  13. Transverse Echo Measurements in RHIC

    SciTech Connect

    Fischer, Wolfram

    2006-03-20

    Diffusion counteracts cooling and the knowledge of diffusion rates is important for the calculation of cooling times and equilibrium beam sizes. Echo measurements are a potentially sensitive method to determine diffusion rates, and longitudinal measurements were done in a number of machines. We report on transverse echo measurements in RHIC and the observed dependence of echo amplitudes on a number of parameters for beams of gold and copper ions, and protons. In particular we examine the echo amplitudes of gold and copper ion bunches of varying intensity, which exhibit different diffusion rates from intrabeam scattering.

  14. TRANSVERSE ECHO MEASUREMENTS IN RHIC.

    SciTech Connect

    FISCHER, W.

    2005-09-18

    Diffusion counteracts cooling and the knowledge of diffusion rates is important for the calculation of cooling times and equilibrium beam sizes. Echo measurements are a potentially sensitive method to determine diffusion rates, and longitudinal measurements were done in a number of machines. We report on transverse echo measurements in RHIC and the observed dependence of echo amplitudes on a number of parameters for beams of gold and copper ions, and protons. In particular they examine the echo amplitudes of gold and copper ion bunches of varying intensity, which exhibit different diffusion rates from intrabeam scattering.

  15. A Transversely Isotropic Thermoelastic Theory

    NASA Technical Reports Server (NTRS)

    Arnold, S. M.

    1989-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Yun, Hee Mann; DiCarlo, James A.

    1997-01-01

    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.

  17. Investigating rupture process of Parkfield seismicity

    NASA Astrophysics Data System (ADS)

    Kim, Ah Yi

    structure biased results, though additional work is needed to confirm this. In another study I investigated the rupture process of micro-earthquakes (M2 target events) at Parkfield using nearly collocated smaller earthquakes as empirical Green's functions (eGf). The result of synthetic tests shows that a direct eGf waveform inversion method predicts the slip model, and the target event waveforms better than a eGf deconvolution approach to invert recovered moment rate functions. I applied the direct eGf waveform inversion to the M2 SAFOD repeating earthquakes, and found that the events have a roughly circular slip distribution with small dimension, high slip amplitude, and corresponding very high stress drop that indicate that high strength asperities exist on the San Andreas fault. Finally, I performed 3D ground motion simulations for 10 small to moderate earthquakes (Mw 4.1--5.4) in the San Francisco Bay Area to evaluate two versions of the USGS 3D velocity model (Brocher, 2005; Jachens et al., 2006; Brocher, 2008) in terms of modeling phase arrival timing, peak ground motion amplitudes, and the capability of the models to simulate strong ground motions for earthquake hazard scenarios. P and S wave timing are well modeled by the velocity models, however, there remain discrepancies in estimated amplitudes and durations that require further calibration. Simulated pseudo spectral acceleration at long period (1 and 3 seconds) compared well with observation. The comparison of peak ground velocity (PGV) for both models reveals that both predict the observed PGV well over four orders of magnitude, however there is an approximate 3-fold dispersion between predicted and observed values due to unaccounted for 3D structure and site effects. Keeping in mind the dispersion, due to the long-period nature of PGV the strong correlation between observed and predicted motions indicate that the 3D models are suitable for scenario earthquake PGV ground motion simulation.

  18. Influence of grinding direction on fracture strength of silicon nitride

    SciTech Connect

    Strakna, T.J.; Jahanmir, S.; Allor, R.L.; Kumar, K.V.

    1995-12-31

    It is generally found that grinding transverse to the tensile stress direction in flexure bars subjected to four-point bending results in a lower strength compared to grinding in the longitudinal direction. In the present study, standard flexure specimens made from a reaction-bonded and a sintered reaction-bonded silicon nitride (RBSN and SRBSN) were surface ground under three different conditions in both longitudinal and transverse directions to assess the effect of grinding direction on strength. Four-point flexure tests were performed on the specimens and Weibull parameters were calculated. The results showed that while the strength was not affected by the grinding condition when grinding was performed in the longitudinal direction, the strength of the samples ground in the transverse direction was reduced as the material removal rate was increased by a factor of 30. This result was confirmed by fractography, which showed that almost all the fracture initiation sites in the longitudinally ground samples were associated with near-surface microstructural features, whereas in the transverse ground samples fracture initiated from damage introduced by grinding. The strength reduction by grinding in the transverse direction was found to be material dependent, and was larger for SRBSN than for RBSN.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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 °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 °C under prolonged, constant tensile loading as compared to shear loading. The tensile creep strength at a rupture time of 1000 h is about 9% of the average tensile joint strength, while the shear creep strength at 1000 h 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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 °C and 300 °C 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 °C as Vf is increased from 13% to 37%. The tensile strength reached up to 1246 MPa at 20 °C 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 °C, 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 °C. 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 °C, while comparable at RT, although the SCS6 fiber has a higher strength than the Sigma fiber. Such a

  1. Sotalol for the protection of turkeys from the development of β-aminopropionitrile-induced aortic ruptures

    PubMed Central

    Simpson, Charles F.

    1972-01-01

    1. The influence of feeding 2 levels of sotalol on the incidence of β-aminopropionitrile (BAPN)-induced aortic ruptures of immature turkeys was determined. 2. Four of 22 turkeys fed 0·12% sotalol and 0·07% BAPN died of aortic ruptures, but 6 of 21 turkeys fed only BAPN died of the syndrome. 3. Blood pressure, heart rate, aortic tensile strength, and aortic structure as seen by light- and electron-microscope were similar in turkeys fed BAPN alone or both BAPN and 0·12% sotalol concurrently. 4. In a second experiment, 13 of 24 turkeys fed 0·7% BAPN alone died of aortic ruptures, but only 2 of 24 turkeys fed BAPN and 0·2% sotalol concurrently died of the disease. 5. Aortic tensile strength was lower, heart rate was faster, alterations of aortic elastic fibres as seen by light- and electron-microscope were more severe, and aortic salt soluble collagen with a higher amino acid content was increased in turkeys fed only BAPN, as compared to turkeys fed both BAPN and 0·2% sotalol. PMID:4561180

  2. Isolated Total Rupture of Extraocular Muscles

    PubMed Central

    Chen, Jingchang; Kang, Ying; Deng, Daming; Shen, Tao; Yan, Jianhua

    2015-01-01

    Abstract Total rupture of extraocular muscles is an infrequent clinical finding. Here we conducted this retrospective study to evaluate their causes of injury, clinical features, imaging, surgical management, and final outcomes in cases of isolated extraocular muscle rupture at a tertiary center in China. Thirty-six patients were identified (24 men and 12 women). Mean age was 34 years (range 2–60). The right eye was involved in 21 patients and the left 1 in 15. A sharp object or metal hook was the cause of this lesion in 16 patients, sinus surgery in 14 patients, traffic accident in 3 patients, orbital surgery in 2 patients, and conjunctive tumor surgery in 1 patient. The most commonly involved muscles were medial (18 patients) and inferior rectus muscles (13 patients). The function of the ruptured muscles revealed a scale of −3 to −4 defect of ocular motility and the amount of deviation in primary position varied from 10 to 140 PD (prism diopter). Computerized tomography (CT) confirmed the presence of ruptured muscles. An end-to-end muscle anastomosis was performed and 3 to 5 mm of muscle was resected in 23 patients. When the posterior border of the injured muscle could not be identified (13 patients), a partial tendon transposition was performed, together with recession of the antagonist in most patients, whereas a recession of the antagonist muscle plus a resection of the involved muscle with or without nasal periosteal fixation was performed in the remaining patients. After an average of 16.42 months of follow-up an excellent result was achieved in 23 patients and results of 13 patients were considered as a failure. In most patients, the posterior border of the ruptured muscle can be identified and an early surgery can be performed to restore function. Alternatively, a partial tendon transposition should be performed. When muscular rupture is suspected, an early orbital CT is required to confirm this possibility, which can then verify the necessity for

  3. Creep-rupture behavior of seven iron-base alloys after long term aging at 760 deg in low pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Witzke, W. R.; Stephens, J. R.

    1980-01-01

    Seven candidate iron-base alloys for heater tube application in the Stirling automotive engine were aged for 3500 hours at 760 C in argon and hydrogen. Aging degraded the tensile and creep-rupture properties. The presence of hydrogen during aging caused additional degradiation of the rupture strength in fine grain alloys. Based on current design criteria for the Mod 1 Stirling engine, N-155 and 19-9DL are considered the only alloys in this study with strengths adequate for heater tube service at 760 C.

  4. Advanced analysis of the transverse bulkhead of the a general cargo ship

    NASA Astrophysics Data System (ADS)

    Axinte, T.; Nutu, C.; Stanca, C.; Cupsa, O.; Carp, A.

    2016-08-01

    The paper presents the main strength factors stressing the transverse bulkhead of a cargo ship. The transverse bulkhead is one of the main components of the hull for a general cargo vessel. There are presented the role and the importance of the general cargo vessel's type using an original drawing made in NX 8.0 Software from Siemens. Further on, we are presented the importance of the transverse bulkhead of the general cargo ship's hull. Next there are analysed the formability of the transverse bulkhead's material and then we are determining the shear, normal and von Mises stresses in the traverse bulkhead, using the finite element method. Once the stresses are computed, there are also determined the fatigue life, strength safety factor and fatigue safety factor. The analysis of the transverse bulkhead is important for the safety of the general cargo vessel type because if this component of the ship does not resist to the various stresses and high deformations during bad storms on the sea or if the cargo is stored inappropriately, deformations or even breakage of the transverse bulkhead can occur, thus causing damages of the cargo ship, especially under heavy storm.

  5. Lifetimes statistics for single Kevlar 49 aramid filaments in creep-rupture at elevated temperatures

    SciTech Connect

    Wu, H.F.

    1987-01-01

    Kevlar 49 fibrous composites are routinely fabricated to have strengths above 1.5 GPa(200 ksi), but in many applications one would like to sustain such stresses for long time periods, sometimes at elevated temperatures. Thus the temperature dependence of the creep-rupture process in the fibers is of interest. Experimental data are presented for the lifetime of single Kevlar 49 filaments under constant stress at elevated temperatures. The goal of this research was to fully characterize the statistical strength and lifetime behavior of single filaments in order to separate fiber effects from fiber/matrix interactions in the creep-rupture lifetime of Kevlar 49/epoxy composites as described for example in Phoenix and Wu (1983). First we conducted experiments to determine distributions for the strength of filaments from the two distinct spools as a function of temperature. As expected, the data could generally be fitted by a two-parameter Weibull distribution. Lifetime experiments at 80 and 130/sup 0/C were conducted at several stress levels chosen as suitable fractions of the Weibull scale parameter for short-term strength for that temperature. The lifetime data were well modelled by a two-parameter Weibull distribution with large variability.

  6. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation

    PubMed Central

    Saltzman, Bryan M.; Harris, Joshua D.; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  7. Earthquake ruptures modulated by waves in damaged fault zones

    NASA Astrophysics Data System (ADS)

    Huang, Yihe; Ampuero, Jean-Paul; Helmberger, Don V.

    2014-04-01

    Faults are usually surrounded by damaged zones of lower elastic moduli and seismic wave velocities than their host rocks. If the interface between the damaged rocks and host rocks is sharp enough, earthquakes happening inside the fault zone generate reflected waves and head waves, which can interact with earthquake ruptures and modulate rupture properties such as rupture speed, slip rate, and rise time. We find through 2-D dynamic rupture simulations the following: (1) Reflected waves can induce multiple slip pulses. The rise time of the primary pulse is controlled by fault zone properties, rather than by frictional properties. (2) Head waves can cause oscillations of rupture speed and, in a certain range of fault zone widths, a permanent transition to supershear rupture with speeds that would be unstable in homogeneous media. (3) Large attenuation smears the slip rate function and delays the initial acceleration of rupture speed but does not affect significantly the rise time or the period of rupture speed oscillations. (4) Fault zones cause a rotation of the background stress field and can induce plastic deformations on both extensional and compressional sides of the fault. The plastic deformations are accumulated both inside and outside the fault zone, which indicates a correlation between fault zone development and repeating ruptures. Spatially periodic patterns of plastic deformations are formed due to oscillating rupture speed, which may leave a permanent signature in the geological record. Our results indicate that damaged fault zones with sharp boundaries promote multiple slip pulses and supershear ruptures.

  8. Rupture Process During the 2015 Illapel, Chile Earthquake: Zigzag-Along-Dip Rupture Episodes

    NASA Astrophysics Data System (ADS)

    Okuwaki, Ryo; Yagi, Yuji; Aránguiz, Rafael; González, Juan; González, Gabriel

    2016-04-01

    We constructed a seismic source model for the 2015 M W 8.3 Illapel, Chile earthquake, which was carried out with the kinematic waveform inversion method adopting a novel inversion formulation that takes into account the uncertainty in the Green's function, together with the hybrid backprojection method enabling us to track the spatiotemporal distribution of high-frequency (0.3-2.0 Hz) sources at high resolution by using globally observed teleseismic P-waveforms. A maximum slip amounted to 10.4 m in the shallow part of the seismic source region centered 72 km northwest of the epicenter and generated a following tsunami inundated along the coast. In a gross sense, the rupture front propagated almost unilaterally to northward from the hypocenter at <2 km/s, however, in detail the spatiotemporal slip distribution also showed a complex rupture propagation pattern: two up-dip rupture propagation episodes, and a secondary rupture episode may have been triggered by the strong high-frequency radiation event at the down-dip edge of the seismic source region. High-frequency sources tends to be distributed at deeper parts of the slip area, a pattern also documented in other subduction zone megathrust earthquakes that may reflect the heterogeneous distribution of fracture energy or stress drop along the fault. The weak excitation of high-frequency radiation at the termination of rupture may represent the gradual deceleration of rupture velocity at the transition zone of frictional property or stress state between the megathrust rupture zone and the swarm area.

  9. An unusual diagnosis of splenic rupture

    PubMed Central

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

    2014-01-01

    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

  10. [Postmortem gastrointestinal ruptures in burn cadavers].

    PubMed

    Schneider, V; Pietrzak, T; Klöppel, I

    1986-01-01

    The report informs on ruptures within the area of the gastro-intestinal tract of two siblings (2 and 3 years of age) that were fatally burned in their apartment. The ruptures are obviously pointing to an "explosive-like" evaporation of the watery part of the gastro-intestinal contents under the influence of the heat, at impeded pressure balance through shrinking of the esophagus caused by the heat in the upper area and the closure of the pylorus. Of significance here is surely also the shrinking of the gastro-intestinal wall caused by the heat and the thin abdominal walls which were not likely to have acted as "heat insulators". These findings are a supplement to the burn hematoma of the stomach as described by Berg and Schumann (1985). PMID:3963991

  11. Computational model of retinal photocoagulation and rupture

    NASA Astrophysics Data System (ADS)

    Sramek, Christopher; Paulus, Yannis M.; Nomoto, Hiroyuki; Huie, Phil; Palanker, Daniel

    2009-02-01

    In patterned scanning laser photocoagulation, shorter duration (< 20 ms) pulses help reduce thermal damage beyond the photoreceptor layer, decrease treatment time and minimize pain. However, safe therapeutic window (defined as the ratio of rupture threshold power to that of light coagulation) decreases for shorter exposures. To quantify the extent of thermal damage in the retina, and maximize the therapeutic window, we developed a computational model of retinal photocoagulation and rupture. Model parameters were adjusted to match measured thresholds of vaporization, coagulation, and retinal pigment epithelial (RPE) damage. Computed lesion width agreed with histological measurements in a wide range of pulse durations and power. Application of ring-shaped beam profile was predicted to double the therapeutic window width for exposures in the range of 1 - 10 ms.

  12. Rupture of the round window membrane.

    PubMed

    Taylor, P H; Bicknell, P G

    1976-01-01

    A case of sudden deafness due to rupture of the round window membrane is presented. Nineteen similar cases have previously been reported in the literature. In a review of these twenty patients, it is noted that a history of concurrent physical effort or barotrauma was present in eighteen. This supports the view that the injury is produced by pressure changes acting either along the cochlear aqueduct (the explosive route) or, directly on the middle ear structures (the implosive route). At operation, the rupture may be difficult to see, and a separate leak from the oval window may be present. The timing of any surgical intervention is important. The authors recommend that this should be deferred for one week after the onset of symptoms, as the fistula may heal spontaneously. If no definite improvement has occurred at the end of this time, then tympanotomy should be undertaken during the next week.

  13. Liquid salt environment stress-rupture testing

    DOEpatents

    Ren, Weiju; Holcomb, David E.; Muralidharan, Govindarajan; Wilson, Dane F.

    2016-03-22

    Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

  14. Surgical treatment of gastrocnemius muscle ruptures.

    PubMed

    Cheng, Yu; Yang, Hui-lin; Sun, Zhi-yong; Ni, Li; Zhang, Hong-tao

    2012-11-01

    Rupture of the medial head of the gastrocnemius, known as "tennis leg", typically occurs when the muscle has been overstretched by dorsiflexion of the ankle with full knee extension. The classic clinical presentation is a middle-aged person who complains of sports-related acute pain in the mid portion of the calf, associated with a snapping sensation. Magnetic resonance imaging (MRI) or ultrasound is often required to evaluate patients with this condition. This injury is usually managed non-operatively, surgical treatment rarely being indicated according to published reports. One case of longstanding and one of recent rupture of the musculotendinous junction of the medial head of the gastrocnemius that were successfully treated by surgical repair are presented here and the MRI characteristics and indications for surgery are discussed.

  15. Strong transverse coupling in the Tevatron

    SciTech Connect

    Annala, G; Carson, J; Edwards, Don; Gelfand, N; Harding, D; Johnson, T; Johnstone, J; Martens, M; Sen, T; Syphers, Mike

    2003-03-01

    The Tevatron was designed with an extensive set of correction and adjustment magnets built into the spool pieces in recognition of the circumstance that a superconducting synchrotron was not as easy to modify as its conventional forebearers. Recently, concern has mounted at the high excitation of the skew quadrupole correctors. The purpose of this note is to account for this situation. When slow extraction was attempted from the Main Ring in the summer of 1970 horizontal-vertical coupling prevented adequate transverse oscillation growth for efficient slow spill. This situation was corrected by an 8 mrad roll of each of twelve equi-spaced quadrupoles [1]. In order to avoid a repetition of this problem in the Tevatron, an extremely strong skew quadrupole circuit was built in at the outset. When the Tevatron was commissioned only 4$ of the capability of this circuit was required. Now, 20 years later, the excitation of this skew quadrupole circuit is approximately 60%. Other skew quadrupole correctors were installed in the neighborhood of the long straight sections, and for a variety of reasons the number of elements in the strong circuit was reduced from 48 to 42. These are relatively minor changes in the present context. Recall that in the normal Tevatron tuning process the skew quad circuits are adjusted to minimize the difference between the horizontal and vertical tunes to the level of {Delta}{nu}{sub min} {approx} 0.003. Normally the horizontal-vertical coupling is not observed directly by orbit measurements during this procedure. it was recognized that the strength of the skew quadrupole settings would imply an uncorrected minimum tune difference of 0.2 units. Clearly, with the skew quad circuit turned off the coupling of the orbital motion should be easily observable. In the following sections, the authors describe the recent Tevatron studies that exhibit the transverse coupling and the analyses that link these observations to the long term development of a

  16. Vulnerability to rupture of the intact articular surface with respect to age and proximity to site of fibrillation: a dynamic and static-investigation.

    PubMed

    Flachsmann, René; Kim, Woong; Broom, Neil

    2005-01-01

    Bovine cartilage-on-bone samples taken from healthy mature patellae and from the intact regions of degenerate patellae were subjected to dynamic and static compressive loading. In-plane articular surface strain and rupture behavior were investigated and compared with previously published data obtained from immature bovine patellae. Both aging and proximity of the intact tested region to the fibrillated lesion increase the likelihood of articular surface rupture under both impact and static loading. Substantially higher levels of stress can be applied dynamically than statically without increasing the risk of articular surface rupture. Articular surface rupture is a result of lineal strains generated by the indentation profile, but any direct measurement of its in situ rupture strength is not possible. However, differences in both measured articular surface strains and rupture characteristics between the three categories of tissue suggest that there is a progressive reduction in the intrinsic strength of the intact surface layer of cartilage with both aging and proximity to site of fibrillation.

  17. Rupture directivity of moderate earthquakes in northern California

    USGS Publications Warehouse

    Seekins, Linda C.; Boatwright, John

    2010-01-01

    We invert peak ground velocity and acceleration (PGV and PGA) to estimate rupture direction and rupture velocity for 47 moderate earthquakes (3.5≥M≥5.4) in northern California. We correct sets of PGAs and PGVs recorded at stations less than 55–125 km, depending on source depth, for site amplification and source–receiver distance, then fit the residual peak motions to the unilateral directivity function of Ben-Menahem (1961). We independently invert PGA and PGV. The rupture direction can be determined using as few as seven peak motions if the station distribution is sufficient. The rupture velocity is unstable, however, if there are no takeoff angles within 30° of the rupture direction. Rupture velocities are generally subsonic (0.5β–0.9β); for stability, we limit the rupture velocity at v=0.92β, the Rayleigh wave speed. For 73 of 94 inversions, the rupture direction clearly identifies one of the nodal planes as the fault plane. The 35 strike-slip earthquakes have rupture directions that range from nearly horizontal (6 events) to directly updip (5 events); the other 24 rupture partly along strike and partly updip. Two strike-slip earthquakes rupture updip in one inversion and downdip in the other. All but 1 of the 11 thrust earthquakes rupture predominantly updip. We compare the rupture directions for 10 M≥4.0 earthquakes to the relative location of the mainshock and the first two weeks of aftershocks. Spatial distributions of 8 of 10 aftershock sequences agree well with the rupture directivity calculated for the mainshock.

  18. Wrapped Wire Detects Rupture Of Pressure Vessel

    NASA Technical Reports Server (NTRS)

    Hunt, James B.

    1990-01-01

    Simple, inexpensive technique helps protect against damage caused by continuing operation of equipment after rupture or burnout of pressure vessel. Wire wrapped over area on outside of vessel where breakthrough most likely. If wall breaks or burns, so does wire. Current passing through wire ceases, triggering cutoff mechanism stopping flow in vessel to prevent further damage. Applied in other situations in which pipes or vessels fail due to overpressure, overheating, or corrosion.

  19. An unusual presentation of bronchial rupture.

    PubMed

    Goktalay, Tugba; Yaldiz, Sadik; Ozgen Alpaydin, Aylin; Goktan, Cihan; Celik, Pinar

    2011-06-01

    Persistent hydropneumothorax was diagnosed in a 62-year-old female with a history of blunt trauma, although she was treated with chest tube and closed underwater seal drainage. Computed tomography and fiberoptic bronchoscopy findings were consistent with "fallen lung" syndrome. Fiberoptic bronchoscopy also found a cavitary lesion at the right tracheobronchial angle. Forceps biopsy of the cavitary lesion indicated bronchogenic carcinoma. Our final diagnosis was tracheobronchial complete rupture and fallen lung syndrome secondary to malignancy. PMID:21333086

  20. [Bilateral rupture of the quadriceps tendon].

    PubMed

    Modrego, Francisco J; Molina, Juan

    2004-01-01

    Simultaneous, bilateral, and spontaneous rupture of the quadriceps tendon is a very rare injury. Individuals with this injury are usually predisposed by chronic renal disease with secondary hyperparathyroidism, gout, diabetes, and lupus erythematosus. Often, primary diagnostic confusion can lead to a delay in treatment. Two cases of a bilateral lesion of the quadriceps tendon, that were treated surgically using the technique of Scuderi, followed by an intense rehabilitation programme, are presented. Surgical treatment yields satisfactory results.

  1. Rupture Forces among Human Blood Platelets at different Degrees of Activation.

    PubMed

    Nguyen, Thi-Huong; Palankar, Raghavendra; Bui, Van-Chien; Medvedev, Nikolay; Greinacher, Andreas; Delcea, Mihaela

    2016-01-01

    Little is known about mechanics underlying the interaction among platelets during activation and aggregation. Although the strength of a blood thrombus has likely major biological importance, no previous study has measured directly the adhesion forces of single platelet-platelet interaction at different activation states. Here, we filled this void first, by minimizing surface mediated platelet-activation and second, by generating a strong adhesion force between a single platelet and an AFM cantilever, preventing early platelet detachment. We applied our setup to measure rupture forces between two platelets using different platelet activation states, and blockade of platelet receptors. The rupture force was found to increase proportionally to the degree of platelet activation, but reduced with blockade of specific platelet receptors. Quantification of single platelet-platelet interaction provides major perspectives for testing and improving biocompatibility of new materials; quantifying the effect of drugs on platelet function; and assessing the mechanical characteristics of acquired/inherited platelet defects.

  2. Slip-pulse rupture behavior on a 2 m granite fault

    NASA Astrophysics Data System (ADS)

    McLaskey, Gregory C.; Kilgore, Brian D.; Beeler, Nicholas M.

    2015-09-01

    We describe observations of dynamic rupture events that spontaneously arise on meter-scale laboratory earthquake experiments. While low-frequency slip of the granite sample occurs in a relatively uniform and crack-like manner, instruments capable of detecting high-frequency motions show that some parts of the fault slip abruptly (velocity > 100 mm s-1, acceleration > 20 km s-2) while the majority of the fault slips more slowly. Abruptly slipping regions propagate along the fault at nearly the shear wave speed. We propose that the dramatic reduction in frictional strength implied by this pulse-like rupture behavior has a common mechanism to the weakening reported in high-velocity friction experiments performed on rotary machines. The slip pulses can also be identified as migrating sources of high-frequency seismic waves. As observations from large earthquakes show similar propagating high-frequency sources, the pulses described here may have relevance to the mechanics of larger earthquakes.

  3. Rupture Forces among Human Blood Platelets at different Degrees of Activation

    PubMed Central

    Nguyen, Thi-Huong; Palankar, Raghavendra; Bui, Van-Chien; Medvedev, Nikolay; Greinacher, Andreas; Delcea, Mihaela

    2016-01-01

    Little is known about mechanics underlying the interaction among platelets during activation and aggregation. Although the strength of a blood thrombus has likely major biological importance, no previous study has measured directly the adhesion forces of single platelet-platelet interaction at different activation states. Here, we filled this void first, by minimizing surface mediated platelet-activation and second, by generating a strong adhesion force between a single platelet and an AFM cantilever, preventing early platelet detachment. We applied our setup to measure rupture forces between two platelets using different platelet activation states, and blockade of platelet receptors. The rupture force was found to increase proportionally to the degree of platelet activation, but reduced with blockade of specific platelet receptors. Quantification of single platelet-platelet interaction provides major perspectives for testing and improving biocompatibility of new materials; quantifying the effect of drugs on platelet function; and assessing the mechanical characteristics of acquired/inherited platelet defects. PMID:27146004

  4. Transverse-longitudinal integrated resonator

    DOEpatents

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

    2003-03-11

    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.

  5. Transverse section radionuclide scanning system

    DOEpatents

    Kuhl, David E.; Edwards, Roy Q.

    1976-01-01

    This invention provides a transverse section radionuclide scanning system for high-sensitivity quantification of brain radioactivity in cross-section picture format in order to permit accurate assessment of regional brain function localized in three-dimensions. High sensitivity crucially depends on overcoming the heretofore known raster type scanning, which requires back and forth detector movement involving dead-time or partial enclosure of the scan field. Accordingly, this invention provides a detector array having no back and forth movement by interlaced detectors that enclose the scan field and rotate as an integral unit around one axis of rotation in a slip ring that continuously transmits the detector data by means of laser emitting diodes, with the advantages that increased amounts of data can be continuously collected, processed and displayed with increased sensitivity according to a suitable computer program.

  6. Gluonic transversity from lattice QCD

    NASA Astrophysics Data System (ADS)

    Detmold, W.; Shanahan, P. E.

    2016-07-01

    We present an exploratory study of the gluonic structure of the ϕ meson using lattice QCD (LQCD). This includes the first investigation of gluonic transversity via the leading moment of the twist-2 double-helicity-flip gluonic structure function Δ (x ,Q2). This structure function only exists for targets of spin J ≥1 and does not mix with quark distributions at leading twist, thereby providing a particularly clean probe of gluonic degrees of freedom. We also explore the gluonic analogue of the Soffer bound which relates the helicity flip and nonflip gluonic distributions, finding it to be saturated at the level of 80%. This work sets the stage for more complex LQCD studies of gluonic structure in the nucleon and in light nuclei where Δ (x ,Q2) is an "exotic glue" observable probing gluons in a nucleus not associated with individual nucleons.

  7. Transversal magnetoresistance in Weyl semimetals

    NASA Astrophysics Data System (ADS)

    Klier, J.; Gornyi, I. V.; Mirlin, A. D.

    2015-11-01

    We explore theoretically the magnetoresistivity of three-dimensional Weyl and Dirac semimetals in transversal magnetic fields within two alternative models of disorder: (i) short-range impurities and (ii) charged (Coulomb) impurities. Impurity scattering is treated using the self-consistent Born approximation. We find that an unusual broadening of Landau levels leads to a variety of regimes of the resistivity scaling in the temperature-magnetic field plane. In particular, the magnetoresistance is nonmonotonous for the white-noise disorder model. For H →0 the magnetoresistance for short-range impurities vanishes in a nonanalytic way as H1 /3. In the limits of strongest magnetic fields H , the magnetoresistivity vanishes as 1 /H for pointlike impurities, while it is linear and positive in the model with Coulomb impurities.

  8. Rupture models with dynamically determined breakdown displacement

    USGS Publications Warehouse

    Andrews, D.J.

    2004-01-01

    The critical breakdown displacement, Dc, in which friction drops to its sliding value, can be made dependent on event size by specifying friction to be a function of variables other than slip. Two such friction laws are examined here. The first is designed to achieve accuracy and smoothness in discrete numerical calculations. Consistent resolution throughout an evolving rupture is achieved by specifying friction as a function of elapsed time after peak stress is reached. Such a time-weakening model produces Dc and fracture energy proportional to the square root of distance rupture has propagated in the case of uniform stress drop. The second friction law is more physically motivated. Energy loss in a damage zone outside the slip zone has the effect of increasing Dc and limiting peak slip velocity (Andrews, 1976). This article demonstrates a converse effect, that artificially limiting slip velocity on a fault in an elastic medium has a toughening effect, increasing fracture energy and Dc proportionally to rupture propagation distance in the case of uniform stress drop. Both the time-weakening and the velocity-toughening models can be used in calculations with heterogeneous stress drop.

  9. Isolated unilateral rupture of the alar ligament.

    PubMed

    Wong, Sui-To; Ernest, Kimberly; Fan, Grace; Zovickian, John; Pang, Dachling

    2014-05-01

    Only 6 cases of isolated unilateral rupture of the alar ligament have been previously reported. The authors report a new case and review the literature, morbid anatomy, and pathogenesis of this rare injury. The patient in their case, a 9-year-old girl, fell head first from a height of 5 feet off the ground. She presented with neck pain, a leftward head tilt, and severe limitation of right rotation, extension, and right lateral flexion of the neck. Plain radiographs and CT revealed no fracture but a shift of the dens toward the right lateral mass of C-1. Magnetic resonance imaging of the cervical spine showed signal hyperintensity within the left dens-atlas space on both T1- and T2-weighted sequences and interruption of the expected dark signal representing the left alar ligament, suggestive of its rupture. After 12 weeks of immobilization in a Guilford brace, MRI showed lessened dens deviation, and the patient attained full and painless neck motion. Including the patient in this case, the 7 patients with this injury were between 5 and 21 years old, sustained the injury in traffic accidents or falls, presented with marked neck pain, and were treated with external immobilization. All patients had good clinical outcome. The mechanism of injury is hyperflexion with rotation. Isolated unilateral alar ligament rupture is a diagnosis made by excluding associated fracture, dislocation, or disruption of other major ligamentous structures in the craniovertebral junction. CT and MRI are essential in establishing the diagnosis. External immobilization is adequate treatment.

  10. Dynamics of retinal photocoagulation and rupture

    NASA Astrophysics Data System (ADS)

    Sramek, Christopher; Paulus, Yannis; Nomoto, Hiroyuki; Huie, Phil; Brown, Jefferson; Palanker, Daniel

    2009-05-01

    In laser retinal photocoagulation, short (<20 ms) pulses have been found to reduce thermal damage to the inner retina, decrease treatment time, and minimize pain. However, the safe therapeutic window (defined as the ratio of power for producing a rupture to that of mild coagulation) decreases with shorter exposures. To quantify the extent of retinal heating and maximize the therapeutic window, a computational model of millisecond retinal photocoagulation and rupture was developed. Optical attenuation of 532-nm laser light in ocular tissues was measured, including retinal pigment epithelial (RPE) pigmentation and cell-size variability. Threshold powers for vaporization and RPE damage were measured with pulse durations ranging from 1 to 200 ms. A finite element model of retinal heating inferred that vaporization (rupture) takes place at 180-190°C. RPE damage was accurately described by the Arrhenius model with activation energy of 340 kJ/mol. Computed photocoagulation lesion width increased logarithmically with pulse duration, in agreement with histological findings. The model will allow for the optimization of beam parameters to increase the width of the therapeutic window for short exposures.

  11. [Traumatic rupture of the thoracic aorta].

    PubMed

    Glock, Y; Roux, D; Soula, P; Cerene, A; Fournial, G

    1996-01-01

    This is a retrospective analysis of 50 postraumatic aortic rupture (1968-1996, 39 males, mean age: 34.5). Group A is composed of 35 patients with an acute aortic rupture and a prompt diagnosis. Group B includes 13 patients with a chronic rupture. All patients from group A had a severe politraumatism with abdominal, cranial, extremities or hip fractures. Mediastinal thickening with or without hemothorax indicated an angiography or a transesophageal echocardiography lately. In group A, 36 patients have been operated on urgently (12-24 hours); cardiopulmonary bypass was performed on 20 patients; an aorto-aortical bypass was done in 27 cases and a direct suture in the remaining 9. In group B, cardiopulmonary bypass was performed on 9 patients; a aorto-aortical bypass was done in 11 cases and a direct suture in 2. Overall hospital mortality was 16%; 19% in group A and 7.6% in group B. Ischemic paraplejia appeared in 5 patients (10%), all from group A. No false aneurysm developed after 4.5 years of follow-up (3-135 months) in the 38 survivors. The usefulness of transesophageal echocardiography, the importance of medular protection and the utility of several interventionist radiologic techniques are discussed. PMID:9053930

  12. Isolated medial head of triceps rupture

    PubMed Central

    Marappa Ganeshan, Raghavendra; Keerthi, Naveen

    2014-01-01

    Triceps ruptures are less common injuries presenting to the orthopaedic or emergency department setting compared with other musculoskeletal injuries. This to some extent reduces the level of index of suspicion or chances of considering the triceps rupture as one of the differential diagnosis while examining a patient following upper limb injury. The literature search shows that a significant proportion of patient diagnosis has been missed during initial presentation, leading to a delay in diagnosis and in providing definitive treatment, ranging from 6 to 18 months. The triceps are the primary extensor of the elbow and are supplied with the radial nerve. Any injury to the triceps can adversely affect the functioning of the limb and influence the ability to work and return to employment. We share our experience of treating a patient with a triceps rupture, in whom the diagnosis was made 6 months after injury; the patient was able to return to manual work 3 months after surgical repair. PMID:25362186

  13. Single Event Gate Rupture in EMCCD technology

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  14. Carotid artery rupture and cervicofacial actinomycosis.

    PubMed

    Kummer, Anne; Lhermitte, Benoît; Ödman, Micaela; Grabherr, Silke; Mangin, Patrice; Palmiere, Cristian

    2012-11-01

    Cervicofacial actinomycosis is an uncommon, progressive infection caused by bacilli of the Actinomyces genus. Actinomyces are common commensal saprophytes in the oral cavity which may have medical importance as facultative pathogens. Subsequent to local injuries to the oral mucosa, they may penetrate the deep tissues and be responsible for suppurative or granulomatous infections. We herein report a case of a 65-year-old man who underwent surgery followed by chemotherapy and radiotherapy for a tonsillar carcinoma. An ulcerous lesion in the base of the tongue developed and spread to the carotid artery wall. The man died of a massive hemorrhage due to left carotid artery rupture. Postmortem computed tomography angiography performed prior to autopsy allowed the precise localization of the source of bleeding to be detected. Postmortem biochemical investigations confirmed the presence of inflammation associated with local bacterial infection. Histological investigations revealed the rupture of the left carotid artery surrounded by numerous colonies of Actinomyces. Acute and chronic inflammation with tissue necrosis as well as post-actinic, fibrotic changes were also found in the tissues surrounding the ruptured artery wall. PMID:22819527

  15. Heating and Weakening of Major Faults During Seismic Rupture

    NASA Astrophysics Data System (ADS)

    Rice, J. R.

    2007-12-01

    The absence of significant heat flow from major fault zones, and scarcity of evidence for their seismic melting, means that during earthquake slip such zones could not retain shear strength comparable to the typically high static friction strength of rocks. One line of explanation is that they are actually statically weak, which could be because materials of exceptionally low friction (smectites, talc) accumulate along fault zones, or perhaps because pore pressure within the fault core is far closer to lithostatic than hydrostatic. Without dismissing either, the focus here is on how thermal processes during the rapid slips of seismic rupture can weaken a fault which is indeed statically strong. (The discussion also leaves aside another kind of non- thermal dynamic weakening, possible when there is dissimilarity in seismic properties across the fault, and/or in poroelastic properties and permeability within fringes of damaged material immediately adjoining the slip surface. Spatially nonuniform mode II slip like near a propagating rupture front may then induce a substantial reduction in the effective normal stress \\barσ.) The heating and weakening processes to be discussed divide roughly into two camps: (1) Those which are expected to be active from the start of seismic slip, and hence will be present in all earthquakes; and (2) Those that kick-in after threshold conditions of rise of temperature T or accumulation of slip are reached, and hence become a feature of larger, or at least deeper slipping, earthquakes. It has been argued that the two major players of (1) are as follows: (1.1) Flash heating and weakening of frictional contact asperities in rapid slip [Rice, 1999, 2006; Tullis and Goldsby, 2003; Goldsby and Hirth, 2006; Beeler et al., 2007; Yuan and Prakash, 2007]. That gives a strong velocity-weakening character to the friction coefficient, which is consistent with inducing self-healing rupture modes [Noda et al., 2006; Lu et al., 2007]. It is a process

  16. Simultaneous reconstruction of quadriceps tendon rupture after TKA and neglected Achilles tendon rupture.

    PubMed

    Lee, Yong Seuk; Min, Byoung-Hyun; Han, Kyeong-Jin; Cho, Jae Ho; Han, Seung Hwan; Lee, Doo-Hyung; Oh, Kyung Soo

    2010-05-12

    We report a case of simultaneous reconstruction of a quadriceps tendon rupture after total knee arthroplasty (TKA) and neglected Achilles tendon rupture, which occurred before TKA with an ipsilateral hamstring autograft. A 64-year-old woman presented with persistent right knee pain. She also had right heel pain and had received multiple steroid injections at the knee joint and heel. On examination, she showed osteoarthritis in the medial and lateral compartments of the knee joint and an Achilles tendon rupture in the ipsilateral limb. There was skin dimpling and the proximal portion of tendon was migrated. We performed TKA, and the postoperative course was satisfactory. She returned 3 months postoperatively, however, with skin dimpling around the suprapatellar area and weakness of knee extension. Her ankle symptoms were also aggravated because she could not use the knee joint freely. We performed simultaneous reconstruction of the quadriceps tendon and the Achilles tendon using an ipsilateral hamstring autograft.Hamstring autograft offers a good alternative treatment option for rupture repair, particularly with concommitant ruptures of multiple sites when primary repair is not possible or the viability of repaired tissue is poor.

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

    SciTech Connect

    Ar Latin-Small-Letter-Dotless-I bas, Bilgin Kadri Dingil, Guerbuez; Koeroglu, Mert; Uenguel, Uemit; Zaral Latin-Small-Letter-Dotless-I , Aliye Ceylan

    2011-02-15

    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.

  18. Theory of Transverse Spin and Transverse Structure of the Nucleon

    NASA Astrophysics Data System (ADS)

    Koike, Yuji

    2009-10-01

    Large single transverse spin asymmetries (SSA) observed in various collision processes opened a new window to disentangle QCD dynamics and quark-gluon substructure of the nucleon. Since SSA is a ``naively T-odd'' observable, it can only occur as an interference between the scattering amplitudes which have different complex phases in a time-reversal invariant theory like QCD. A conventional framework for hard inclusive processes, i.e. perturbative QCD in the twist-2 level, can only give rise to a negligible asymmetry and thus can not explain the observed data. Understanding the origin of the large SSAs requires the extention of the framework of the QCD hard processes, and by now QCD mechanisms leading to large SSAs have been clarified in greater detail. These mechanisms based on different perspectives introduce new concepts describing the nucleon structure not present in the conventional parton model, such as ``parton's intrinsic transverse momentum'' and ``multi-parton correlations.'' Precise and unambiguous definition of these ideas requires much more careful theoretical analyses than the twist-2 case, in particular, in connection with the universality of the parton distribution/fragmentation functions, gauge invariance and factorization properties of the cross sections. In the literature, QCD mechanisms for SSAs are often classified into two categories. One is based on the (naively) ``T-odd'' distribution and fragmentation functions in the transverse momentum dependent (TMD) factorization approach. Sivers and Collins functions are typical examples for this one. The other one is based on the twist-3 quark-gluon (more generally, multi-parton such as triple-gluon) correlation functions in the collinear factorization approaches. The former mechanism can describe SSAs in the small-pT region (pTQ) as a leading-twist effect, while the latter one describes SSAs in the large pT region as a twist-3 effect. Both approaches have been applied to study SSAs in various

  19. Design prediction for long term stress rupture service of composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Robinson, Ernest Y.

    1992-01-01

    Extensive stress rupture studies on glass composites and Kevlar composites were conducted by the Lawrence Radiation Laboratory beginning in the late 1960's and extending to about 8 years in some cases. Some of the data from these studies published over the years were incomplete or were tainted by spurious failures, such as grip slippage. Updated data sets were defined for both fiberglass and Kevlar composite stand test specimens. These updated data are analyzed in this report by a convenient form of the bivariate Weibull distribution, to establish a consistent set of design prediction charts that may be used as a conservative basis for predicting the stress rupture life of composite pressure vessels. The updated glass composite data exhibit an invariant Weibull modulus with lifetime. The data are analyzed in terms of homologous service load (referenced to the observed median strength). The equations relating life, homologous load, and probability are given, and corresponding design prediction charts are presented. A similar approach is taken for Kevlar composites, where the updated stand data do show a turndown tendency at long life accompanied by a corresponding change (increase) of the Weibull modulus. The turndown characteristic is not present in stress rupture test data of Kevlar pressure vessels. A modification of the stress rupture equations is presented to incorporate a latent, but limited, strength drop, and design prediction charts are presented that incorporate such behavior. The methods presented utilize Cartesian plots of the probability distributions (which are a more natural display for the design engineer), based on median normalized data that are independent of statistical parameters and are readily defined for any set of test data.

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

    USGS Publications Warehouse

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

    2001-01-01

    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

  1. Analysis of factors responsible for the accelerated creep rupture of 12% Cr martensitic steel weld joints

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, A. S.; Okhapkin, K. A.; Mikhailov, M. S.; Skutin, V. S.; Zubova, G. E.; Fedotov, B. V.

    2016-06-01

    In the process of the investigation of the heat resistance of a 0.07C-12Cr-Ni-Mo-V-Nb steel of the martensitic-ferritic class, a reduction was revealed in the long-term strength of its welded joints to below the level of the strength of the base metal. To establish the causes for the accelerated failure of the welded joints, an imitation of the thermal cycles was carried out that produce the structure of the heataffected zone using a dilatometer. In the samples with the structure that corresponds to that of the heataffected zone, a local zone of softening was revealed. The investigations of the metal structure using transmission electron microscopy have shown that the reduction in the creep rupture strength was caused by structural changes under the conditions of the thermal cycle of welding upon the staying of the steel in the temperature range between the Ac 1 and Ac 3 points.

  2. Multi-Scale Effects in the Strength of Ceramics

    PubMed Central

    Cook, Robert F.

    2016-01-01

    Multiple length-scale effects are demonstrated in indentation-strength measurements of a range of ceramic materials under inert and reactive conditions. Meso-scale effects associated with flaw disruption by lateral cracking at large indentation loads are shown to increase strengths above the ideal indentation response. Micro-scale effects associated with toughening by microstructural restraints at small indentation loads are shown to decrease strengths below the ideal response. A combined meso-micro-scale analysis is developed that describes ceramic inert strength behaviors over the complete indentation flaw size range. Nano-scale effects associated with chemical equilibria and crack velocity thresholds are shown to lead to invariant minimum strengths at slow applied stressing rates under reactive conditions. A combined meso-micro-nano-scale analysis is developed that describes the full range of reactive and inert strength behaviors as a function of indentation load and applied stressing rate. Applications of the multi-scale analysis are demonstrated for materials design, materials selection, toughness determination, crack velocity determination, bond-rupture parameter determination, and prediction of reactive strengths. The measurements and analysis provide strong support for the existence of sharp crack tips in ceramics such that the nano-scale mechanisms of discrete bond rupture are separate from the larger scale crack driving force mechanics characterized by continuum-based stress-intensity factors. PMID:27563150

  3. Evolution of the helicity and transversity Transverse-Momentum-Dependent parton distributions

    SciTech Connect

    Prokudin, Alexei; Bacchetta, Alessandro

    2013-07-01

    We examine the QCD evolution of the helicity and transversity parton distribution functions when including also their dependence on transverse momentum. Using an appropriate definition of these polarized transverse momentum distributions (TMDs), we describe their dependence on the factorization scale and rapidity cutoff, which is essential for phenomenological applications.

  4. Evolution of the helicity and transversity Transverse-Momentum-Dependent parton distributions

    SciTech Connect

    Prokudin, Alexey; Bacchetta, Alessandro

    2013-10-01

    We examine the QCD evolution of the helicity and transversity parton distribution functions when including also their dependence on transverse momentum. Using an appropriate definition of these polarized transverse momentum distributions (TMDs), we describe their dependence on the factorization scale and rapidity cutoff, which is essential for phenomenological applications.

  5. Dynamic strength of molecular adhesion bonds.

    PubMed Central

    Evans, E; Ritchie, K

    1997-01-01

    In biology, molecular linkages at, within, and beneath cell interfaces arise mainly from weak noncovalent interactions. These bonds will fail under any level of pulling force if held for sufficient time. Thus, when tested with ultrasensitive force probes, we expect cohesive material strength and strength of adhesion at interfaces to be time- and loading rate-dependent properties. To examine what can be learned from measurements of bond strength, we have extended Kramers' theory for reaction kinetics in liquids to bond dissociation under force and tested the predictions by smart Monte Carlo (Brownian dynamics) simulations of bond rupture. By definition, bond strength is the force that produces the most frequent failure in repeated tests of breakage, i.e., the peak in the distribution of rupture forces. As verified by the simulations, theory shows that bond strength progresses through three dynamic regimes of loading rate. First, bond strength emerges at a critical rate of loading (> or = 0) at which spontaneous dissociation is just frequent enough to keep the distribution peak at zero force. In the slow-loading regime immediately above the critical rate, strength grows as a weak power of loading rate and reflects initial coupling of force to the bonding potential. At higher rates, there is crossover to a fast regime in which strength continues to increase as the logarithm of the loading rate over many decades independent of the type of attraction. Finally, at ultrafast loading rates approaching the domain of molecular dynamics simulations, the bonding potential is quickly overwhelmed by the rapidly increasing force, so that only naked frictional drag on the structure remains to retard separation. Hence, to expose the energy landscape that governs bond strength, molecular adhesion forces must be examined over an enormous span of time scales. However, a significant gap exists between the time domain of force measurements in the laboratory and the extremely fast scale

  6. Noninvasive Vascular Displacement Estimation for Relative Elastic Modulus Reconstruction in Transversal Imaging Planes

    PubMed Central

    Hansen, Hendrik H.G.; Richards, Michael S.; Doyley, Marvin M.; de Korte, Chris L.

    2013-01-01

    Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF) data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2–3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding. PMID:23478602

  7. Noninvasive vascular displacement estimation for relative elastic modulus reconstruction in transversal imaging planes.

    PubMed

    Hansen, Hendrik H G; Richards, Michael S; Doyley, Marvin M; de Korte, Chris L

    2013-01-01

    Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF) data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2-3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding.

  8. Cladding For Transversely-Pumped Laser Rod

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.; Fan, Tso Yee

    1989-01-01

    Combination of suitable dimensioning and cladding of neodymium:yttrium aluminum garnet of similar solid-state laser provides for more efficient utilization of transversely-incident pump light from diode lasers. New design overcomes some of limitations of longitudinal- and older transverse-pumping concepts and promotes operation at higher output powers in TEM00 mode.

  9. Transverse instability at the recycler ring

    SciTech Connect

    Ng, K.Y.; /Fermilab

    2004-10-01

    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.

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

    PubMed

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

    2008-01-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    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.

  12. Application of Strength Diagnosis.

    ERIC Educational Resources Information Center

    Newton, Robert U.; Dugan, Eric

    2002-01-01

    Discusses the various strength qualities (maximum strength, high- and low-load speed strength, reactive strength, rate of force development, and skill performance), noting why a training program design based on strength diagnosis can lead to greater efficacy and better performance gains for the athlete. Examples of tests used to assess strength…

  13. Bilateral patellar tendon rupture associated with statin use

    PubMed Central

    Kearns, Marie C.; Singh, Vinay K.

    2016-01-01

    Patellar tendon rupture is an uncommon clinical presentation, which generally affects the under 40s who are active in sport. Bilateral rupture of both tendons is much rarer. It occurs most frequently in patients with predisposing factors such as corticosteroid use or systemic diseases. The authors present the case of a 56-year-old male on long-term statin therapy who sustained this injury following a fall on ice. He had no known risk factors for tendon rupture. Surgical treatment involved tendon repair using Krakow suture via bony tunnels in the patella. Statins have previously been associated with tendon ruptures at other sites but there have been no published cases of bilateral patellar tendon rupture linked to statin use. We review the literature regarding the association between statins and tendon rupture. PMID:27165749

  14. Recent COMPASS Results on Transverse Physics

    SciTech Connect

    Iwata, Takahiro; Collaboration: COMPASS Collaboration

    2011-12-14

    The investigation of transverse spin and transverse momentum dependent effects in deep inelastic scattering of muons off nucleons is one of the key physics programs of the COMPASS collaboration at CERN. We have investigated the effects from the data obtained with a polarized proton target. In order to access the transversity distribution function, following channels have been analyzed: The azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of lambda hyperons in the final state. The Sivers distribution function which is one of the transverse momentum dependent functions has been investigated also from the azimuthal distribution of single hadrons. Azimuthal asymmetries in unpolarized deep inelastic scattering give important information on the inner structure of the nucleon to access the so-far unmeasured Boer-Mulders function. We have measured these asymmetries using spin-averaged {sup 6}L{sub i}D.

  15. Transverse Spin Effects in SIDIS at COMPASS

    SciTech Connect

    Joosten, Rainer

    2009-12-17

    The measurement of single spin asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) on a transversely polarized target is an important part of the COMPASS physics program. It allows us to investigate the transversity distribution functions as well as transverse momentum dependent distribution functions by measuring azimuthal asymmetries in the hadron production. After COMPASS took data in the years 2002-2004 by scattering a 160 GeV/c muon beam off a transversely polarized deuteron ({sup 6}LiD) target, in 2007 additional data was collected on a transversely polarized proton (NH{sub 3}) target. In this contribution, the latest results on the Collins and Sivers asymmetries in single hadron production as well as two-hadron asymmetries from the analysis of the proton data are presented and compared with existing model predictions.

  16. Recent COMPASS Results on Transverse Physics

    NASA Astrophysics Data System (ADS)

    Iwata, Takahiro

    2011-12-01

    The investigation of transverse spin and transverse momentum dependent effects in deep inelastic scattering of muons off nucleons is one of the key physics programs of the COMPASS collaboration at CERN. We have investigated the effects from the data obtained with a polarized proton target. In order to access the transversity distribution function, following channels have been analyzed: The azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of lambda hyperons in the final state. The Sivers distribution function which is one of the transverse momentum dependent functions has been investigated also from the azimuthal distribution of single hadrons. Azimuthal asymmetries in unpolarized deep inelastic scattering give important information on the inner structure of the nucleon to access the so-far unmeasured Boer-Mulders function. We have measured these asymmetries using spin-averaged 6LiD.

  17. Dynamic rupture processes and seismic radiation in models of earthquake faults separating similar and dissimilar solids

    NASA Astrophysics Data System (ADS)

    Shi, Zheqiang

    This thesis examines dynamic ruptures along frictional interfaces and seismic radiation in models of earthquake faults separating similar and dissimilar solids with the goal of advancing the understanding of earthquake physics. The dynamics of Mode-II rupture along an interface governed by slip-weakening friction between dissimilar solids are investigated. The results show that the wrinkle-like rupture along such interfaces evolves to unilateral propagation in the slip direction of the compliant side for a broad range of conditions, and the closer the initial shear stress is to the static friction the smaller degree of material contrast is needed for this evolution to occur. Transition of the wrinkle-like pulse to crack-like rupture occurs when the reduction of friction coefficient is sufficiently large. Energy partition associated with various rupture modes along an interface governed by rate- and state-dependent friction between identical solids is investigated. The rupture mode changes with varying velocity dependence of friction, strength excess parameter and length of the nucleation zone. High initial shear stress and weak velocity dependence of friction favor crack-like ruptures, while the opposite conditions favor the pulse-like mode. The rupture mode can switch from a subshear single pulse to a supershear train of pulses when the width of the nucleation zone is increased. The elastic strain energy released over the same propagation distance by the different rupture modes has the order: supershear crack, subshear crack, supershear train-of-pulses and subshear single-pulse. General considerations and observations suggest that the subshear pulse and supershear crack are, respectively, the most and least common modes of earthquake ruptures. The effect of plasticity and interface elasticity on dynamic frictional sliding along an interface induced by edge impact loading between two identical elastic-viscoplastic solids is analyzed. The material on each side is

  18. Irregularities in Early Seismic Rupture Propagation for Large Events in a Crustal Earthquake Model

    NASA Astrophysics Data System (ADS)

    Lapusta, N.; Rice, J. R.; Rice, J. R.

    2001-12-01

    behavior at depth. Small events appear in our model at that transition as we decrease the characteristic slip distance for evolution of frictional strength (but not if that distance is unrealistically large). Such clustering of small events at transitions from seismogenic to creeping behavior seems to occur on real faults as well, as we show in examples. To compute moment acceleration that can be compared with data, we translate the results of our 2-D fault model to a 3-D model with essentially radial symmetry on the fault plane. We will discuss limitations of that interpretation; in particular, it may overestimate the effect of partial arrest of rupture in creeping regions. Our present work cannot resolve whether there are any differences in the early phases of seismic moment release, i.e. in the seismic nucleation phase, that would make the beginning of larger events look different from smaller ones that are about to arrest. We have shown that the aseismic nucleation phase and the earliest phases of dynamic breakout are virtually identical for small and large events in our simulations. If early moment release is mostly affected by stress heterogeneities left by previous small events and by creep processes, as our present study suggests, then any such differences would have to be related to as yet unidentified properties of the pre-stress field that might determine the ultimate event size. See http://esag.harvard.edu/lapusta/Lapusta_Rice_Jun01.pdf, Lapusta and Rice, submitted to JGR, 2001.

  19. Electrodeposited, Transverse Nanowire Electroluminescent Junctions.

    PubMed

    Qiao, Shaopeng; Xu, Qiang; Dutta, Rajen K; Le Thai, Mya; Li, Xiaowei; Penner, Reginald M

    2016-09-27

    The preparation by electrodeposition of transverse nanowire electroluminescent junctions (tn-ELJs) is described, and the electroluminescence (EL) properties of these devices are characterized. The lithographically patterned nanowire electrodeposition process is first used to prepare long (millimeters), linear, nanocrystalline CdSe nanowires on glass. The thickness of these nanowires along the emission axis is 60 nm, and the width, wCdSe, along the electrical axis is adjustable from 100 to 450 nm. Ten pairs of nickel-gold electrical contacts are then positioned along the axis of this nanowire using lithographically directed electrodeposition. The resulting linear array of nickel-CdSe-gold junctions produces EL with an external quantum efficiency, EQE, and threshold voltage, Vth, that depend sensitively on wCdSe. EQE increases with increasing electric field and also with increasing wCdSe, and Vth also increases with wCdSe and, therefore, the electrical resistance of the tn-ELJs. Vth down to 1.8(±0.2) V (for wCdSe ≈ 100 nm) and EQE of 5.5(±0.5) × 10(-5) (for wCdSe ≈ 450 nm) are obtained. tn-ELJs produce a broad EL emission envelope, spanning the wavelength range from 600 to 960 nm.

  20. Mechanical behaviour and rupture of normal and pathological human ascending aortic wall.

    PubMed

    García-Herrera, C M; Atienza, J M; Rojo, F J; Claes, E; Guinea, G V; Celentano, D J; García-Montero, C; Burgos, R L

    2012-06-01

    The mechanical properties of aortic wall, both healthy and pathological, are needed in order to develop and improve diagnostic and interventional criteria, and for the development of mechanical models to assess arterial integrity. This study focuses on the mechanical behaviour and rupture conditions of the human ascending aorta and its relationship with age and pathologies. Fresh ascending aortic specimens harvested from 23 healthy donors, 12 patients with bicuspid aortic valve (BAV) and 14 with aneurysm were tensile-tested in vitro under physiological conditions. Tensile strength, stretch at failure and elbow stress were measured. The obtained results showed that age causes a major reduction in the mechanical parameters of healthy ascending aortic tissue, and that no significant differences are found between the mechanical strength of aneurysmal or BAV aortic specimens and the corresponding age-matched control group. The physiological level of the stress in the circumferential direction was also computed to assess the physiological operation range of healthy and diseased ascending aortas. The mean physiological wall stress acting on pathologic aortas was found to be far from rupture, with factors of safety (defined as the ratio of tensile strength to the mean wall stress) larger than six. In contrast, the physiological operation of pathologic vessels lays in the stiff part of the response curve, losing part of its function of damping the pressure waves from the heart. PMID:22391945

  1. Mechanical behaviour and rupture of normal and pathological human ascending aortic wall.

    PubMed

    García-Herrera, C M; Atienza, J M; Rojo, F J; Claes, E; Guinea, G V; Celentano, D J; García-Montero, C; Burgos, R L

    2012-06-01

    The mechanical properties of aortic wall, both healthy and pathological, are needed in order to develop and improve diagnostic and interventional criteria, and for the development of mechanical models to assess arterial integrity. This study focuses on the mechanical behaviour and rupture conditions of the human ascending aorta and its relationship with age and pathologies. Fresh ascending aortic specimens harvested from 23 healthy donors, 12 patients with bicuspid aortic valve (BAV) and 14 with aneurysm were tensile-tested in vitro under physiological conditions. Tensile strength, stretch at failure and elbow stress were measured. The obtained results showed that age causes a major reduction in the mechanical parameters of healthy ascending aortic tissue, and that no significant differences are found between the mechanical strength of aneurysmal or BAV aortic specimens and the corresponding age-matched control group. The physiological level of the stress in the circumferential direction was also computed to assess the physiological operation range of healthy and diseased ascending aortas. The mean physiological wall stress acting on pathologic aortas was found to be far from rupture, with factors of safety (defined as the ratio of tensile strength to the mean wall stress) larger than six. In contrast, the physiological operation of pathologic vessels lays in the stiff part of the response curve, losing part of its function of damping the pressure waves from the heart.

  2. [SURGICAL TREATMENT OF PATIENTS WITH URETERAL RUPTURES].

    PubMed

    Komjakov, B K; Guliev, B G

    2015-01-01

    The aim of the study was to analyze the causes of ureteral ruptures and the types surgical procedures used for their management. Over the period from 2006 to 2014, 7 patients with ureteral ruptures underwent surgical treatment in the Mechnikov N-WSMU clinic. All of them were males aged 50 to 71 years. In all cases, the ureter was injured during ureteroscopy and contact lithotripsy. In two patients the right ureter was cut off at the border of the upper and middle third, in four--at 3-4 cm below pyeloureteral segment, one patient diagnosed with a complete separation of the ureter from the kidney pelvis. Patients, who have suffered a detachment of the ureter in other hospitals, previously underwent surgical exploration of the retroperitoneal space, drainage of the kidney by pyelonephrostomy (5) and ureterocutaneostomy (1). In a case of a patient with an injury that occurred in our clinic, laparoscopic nephrectomy with autologous renal transplantation was carried out. Five patients with extended ureter defects underwent ileo-ureteroplasty. The patient with left ureterocutaneostomy underwent nephrovesical bypass. Patency of the upper urinary tract and kidney function were restored in all patients, all of them were relieved from external drains. The duration of the intestinal plastic averaged 160 minutes, laparoscopic nephrectomy with autologous transplantation--210 min and nephrovesical bypass--110 min. Blood transfusion was required only in autologous graft patient. The ureteral rupture is a serious complication of ureteral endourological procedures in upper urinary tract. It requires such complicated reconstructive operations as autologous transplantation of the kidney or intestinal ureteroplasty. PMID:26390553

  3. Treatment of Ruptured Vertebral Artery Dissecting Aneurysms

    PubMed Central

    Hamasaki, Osamu; Ikawa, Fusao; Hidaka, Toshikazu; Kurokawa, Yasuharu; Yonezawa, Ushio

    2014-01-01

    Summary We evaluated the outcomes of endovascular or surgical treatment of ruptured vertebral artery dissecting aneurysms (VADAs), and investigated the relations between treatment complications and the development and location of the posterior inferior cerebellar artery (PICA). We treated 14 patients (12 men, two women; mean age, 56.2 years) with ruptured VADAs between March 1999 and June 2012 at our hospital. Six and eight patients had Hunt and Hess grades 1-3 and 4-5, respectively. Twelve patients underwent internal endovascular trapping, one underwent proximal endovascular occlusion alone, and one underwent proximal endovascular occlusion in the acute stage and occipital artery (OA)-PICA anastomosis and surgical trapping in the chronic stage. The types of VADA based on their location relative to the ipsilateral PICA were distal, PICA-involved, and non-PICA in nine, two, and three patients, respectively. The types of PICA based on their development and location were bilateral anterior inferior cerebellar artery (AICA)-PICA, ipsilateral AICA-PICA, extradural, and intradural type in one, two, two, and nine patients, respectively. Two patients with high anatomical risk developed medullary infarction, but their midterm outcomes were better than in previous reports. The modified Rankin scale indicated grades 0-2, 3-5, and 6 in eight, three, and three patients, respectively. A good outcome is often obtained in the treatment of ruptured VADA using internal endovascular trapping, except in the PICA-involved type, even with high-grade subarachnoid hemorrhage. Treatment of the PICA-involved type is controversial. The anatomical location and development of PICA may be predicted by complications with postoperative medullary infarction. PMID:24976093

  4. Dynamic stress changes during earthquake rupture

    USGS Publications Warehouse

    Day, S.M.; Yu, G.; Wald, D.J.

    1998-01-01

    We assess two competing dynamic interpretations that have been proposed for the short slip durations characteristic of kinematic earthquake models derived by inversion of earthquake waveform and geodetic data. The first interpretation would require a fault constitutive relationship in which rapid dynamic restrengthening of the fault surface occurs after passage of the rupture front, a hypothesized mechanical behavior that has been referred to as "self-healing." The second interpretation would require sufficient spatial heterogeneity of stress drop to permit rapid equilibration of elastic stresses with the residual dynamic friction level, a condition we refer to as "geometrical constraint." These interpretations imply contrasting predictions for the time dependence of the fault-plane shear stresses. We compare these predictions with dynamic shear stress changes for the 1992 Landers (M 7.3), 1994 Northridge (M 6.7), and 1995 Kobe (M 6.9) earthquakes. Stress changes are computed from kinematic slip models of these earthquakes, using a finite-difference method. For each event, static stress drop is highly variable spatially, with high stress-drop patches embedded in a background of low, and largely negative, stress drop. The time histories of stress change show predominantly monotonic stress change after passage of the rupture front, settling to a residual level, without significant evidence for dynamic restrengthening. The stress change at the rupture front is usually gradual rather than abrupt, probably reflecting the limited resolution inherent in the underlying kinematic inversions. On the basis of this analysis, as well as recent similar results obtained independently for the Kobe and Morgan Hill earthquakes, we conclude that, at the present time, the self-healing hypothesis is unnecessary to explain earthquake kinematics.

  5. Surgical repair of a rupture of the pectoralis major muscle.

    PubMed

    Pochini, Alberto De Castro; Andreoli, Carlos Vicente; Ejnisman, Benno; Maffulli, Nicola

    2015-02-25

    Muscle rupture is rarely treated surgically. Few reports of good outcomes after muscular suture have been published. Usually, muscular lesions or partial ruptures heal with few side effects or result in total recovery. We report a case of an athlete who was treated surgically to repair a total muscular rupture in the pectoralis major muscle. After 6 months, the athlete returned to competitive practice. After a 2-year follow-up, the athlete still competes in skateboard championships.

  6. Uterine rupture following termination of pregnancy in a scarred uterus.

    PubMed

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

    2014-02-01

    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.

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

    PubMed

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

    2014-06-01

    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.

  8. [Spontaneous rupture of the unscarred uterus during labor. Case report].

    PubMed

    Leung, F; Courtois, L; Aouar, Z; Bourtembourg, A; Eckman, A; Terzibachian, J J; Maillet, R; Riethmuller, D

    2009-04-01

    We report a case of spontaneous uterine rupture in a 19 year-old patient Gravida 1 para 2 with no past history of uterine surgery. The diagnosis of uterine rupture, evoked in the early post-partum in the presence of acute abdominal pain, collapsus and haemoperitoneum on ultrasonography, was confirmed by laparotomy. Treatment consisted in hysterorrhaphy. The etiopathogenesis, clinical and therapeutical aspects of spontaneous unscarred uterine ruptures are discussed throughout a literature review.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    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

  10. Embolisation of recently ruptured intracranial aneurysms.

    PubMed Central

    Byrne, J V; Molyneux, A J; Brennan, R P; Renowden, S A

    1995-01-01

    Patients with subarachnoid haemorrhage due to the rupture of aneurysms unsuitable for craniotomy and clipping have been treated by coil embolisation within three weeks. Sixty nine of 75 consecutive patients were successfully treated. Procedure related complications occurred in 10 patients, resulting in permanent neurological deficits in three and one death (4.8%). The Glasgow outcome scores at six weeks were 53 grade 1, seven grade 2, four grade 3, and five grade 5. These results are comparable with surgical series despite a high proportion of aneurysms in the posterior cerebral circulation. Images PMID:7500100

  11. Anisotropy in rupture lines of paper sheets

    NASA Astrophysics Data System (ADS)

    Menezes-Sobrinho, I. L.; Couto, M. S.; Ribeiro, I. R. B.

    2005-06-01

    We have experimentally investigated the fracture process in paper samples submitted to a uniaxial force. Five types of paper sheets (newsprint, towel, sulfite, silk, and couche papers) were fractured along two orthogonal orientations. In order to characterize the rupture lines of the paper sheets we utilized the Hurst exponent. Our results indicate a dependence of the Hurst exponent on the orientation of the paper sheets for samples of newsprint and, probably, towel and silk papers. For the other types of paper the Hurst exponent does not depend on the direction of crack propagation.

  12. Anisotropy in rupture lines of paper sheets.

    PubMed

    Menezes-Sobrinho, I L; Couto, M S; Ribeiro, I R B

    2005-06-01

    We have experimentally investigated the fracture process in paper samples submitted to a uniaxial force. Five types of paper sheets (newsprint, towel, sulfite, silk, and couche papers) were fractured along two orthogonal orientations. In order to characterize the rupture lines of the paper sheets we utilized the Hurst exponent. Our results indicate a dependence of the Hurst exponent on the orientation of the paper sheets for samples of newsprint and, probably, towel and silk papers. For the other types of paper the Hurst exponent does not depend on the direction of crack propagation. PMID:16089834

  13. Complex earthquake rupture and local tsunamis

    USGS Publications Warehouse

    Geist, E.L.

    2002-01-01

    In contrast to far-field tsunami amplitudes that are fairly well predicted by the seismic moment of subduction zone earthquakes, there exists significant variation in the scaling of local tsunami amplitude with respect to seismic moment. From a global catalog of tsunami runup observations this variability is greatest for the most frequently occuring tsunamigenic subduction zone earthquakes in the magnitude range of 7 < Mw < 8.5. Variability in local tsunami runup scaling can be ascribed to tsunami source parameters that are independent of seismic moment: variations in the water depth in the source region, the combination of higher slip and lower shear modulus at shallow depth, and rupture complexity in the form of heterogeneous slip distribution patterns. The focus of this study is on the effect that rupture complexity has on the local tsunami wave field. A wide range of slip distribution patterns are generated using a stochastic, self-affine source model that is consistent with the falloff of far-field seismic displacement spectra at high frequencies. The synthetic slip distributions generated by the stochastic source model are discretized and the vertical displacement fields from point source elastic dislocation expressions are superimposed to compute the coseismic vertical displacement field. For shallow subduction zone earthquakes it is demonstrated that self-affine irregularities of the slip distribution result in significant variations in local tsunami amplitude. The effects of rupture complexity are less pronounced for earthquakes at greater depth or along faults with steep dip angles. For a test region along the Pacific coast of central Mexico, peak nearshore tsunami amplitude is calculated for a large number (N = 100) of synthetic slip distribution patterns, all with identical seismic moment (Mw = 8.1). Analysis of the results indicates that for earthquakes of a fixed location, geometry, and seismic moment, peak nearshore tsunami amplitude can vary by a

  14. Intracranial Aneurysms: Wall Motion Analysis for Prediction of Rupture.

    PubMed

    Vanrossomme, A E; Eker, O F; Thiran, J-P; Courbebaisse, G P; Zouaoui Boudjeltia, K

    2015-10-01

    Intracranial aneurysms are a common pathologic condition with a potential severe complication: rupture. Effective treatment options exist, neurosurgical clipping and endovascular techniques, but guidelines for treatment are unclear and focus mainly on patient age, aneurysm size, and localization. New criteria to define the risk of rupture are needed to refine these guidelines. One potential candidate is aneurysm wall motion, known to be associated with rupture but difficult to detect and quantify. We review what is known about the association between aneurysm wall motion and rupture, which structural changes may explain wall motion patterns, and available imaging techniques able to analyze wall motion. PMID:25929878

  15. Stress rupture resistance. [of Co and Ni superalloys

    NASA Technical Reports Server (NTRS)

    Freche, J. C.

    1976-01-01

    Principles underlying the design of metallic systems for stress rupture resistance are outlined by considering the specific case studies of cobalt- and nickel-base superalloys. Ways in which superalloys can be designed for high stress rupture resistance are discussed. In describing the alloying procedures, the strengthening mechanisms involved and methods of avoiding phases detrimental to stress rupture resistance are identified. New processing techniques such as controlled solidification, prealloyed powder processing, and autoclave heat treatments are described as further means of achieving increased stress rupture resistance in superalloy and other systems.

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

    PubMed

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

    2014-10-01

    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.

  17. Rupture of the distal tendon of the biceps brachii. Operative versus non-operative treatment.

    PubMed

    Baker, B E; Bierwagen, D

    1985-03-01

    We did Cybex testing of thirteen patients who had had a rupture of the distal tendon of the biceps brachii. The tests were performed fifteen months to six years after injury. The ten patients who had had a surgical repair through the two-incision technique showed a return to normal levels of strength and endurance with regard to both flexion of the elbow and supination of the forearm. The three patients who had had conservative treatment showed a remaining deficit in those parameters which was clinically evident in several activities, such as use of a screwdriver or baseball bat.

  18. Rupture of giant vertebrobasilar aneurysm following flow diversion: mechanical stretch as a potential mechanism for early aneurysm rupture.

    PubMed

    Fox, Benjamin; Humphries, William Edward; Doss, Vinodh T; Hoit, Daniel; Elijovich, Lucas; Arthur, Adam S

    2014-01-01

    A patient with a giant symptomatic vertebrobasilar aneurysm was treated by endoscopic third ventriculostomy for obstructive hydrocephalus followed by treatment of the aneurysm by flow diversion using a Pipeline Embolization Device. After an uneventful procedure and initial periprocedural period, the patient experienced an unexpected fatal subarachnoid hemorrhage 1 week later. Autopsy demonstrated extensive subarachnoid hemorrhage and aneurysm rupture (linear whole wall rupture). The patent Pipeline Embolization Device was in its intended location, as was the persistent coil occlusion of the distal left vertebral artery. The aneurysm appeared to rupture in a linear manner and contained a thick large expansile clot that seemed to disrupt or rupture the thin aneurysm wall directly opposite the basilar artery/Pipeline Embolization Device. We feel the pattern of aneurysm rupture in our patient supports the idea that the combination of flow diversion and the resulting growing intra-aneurysmal thrombus can create a mechanical force with the potential to cause aneurysm rupture. PMID:25355741

  19. Rupture of giant vertebrobasilar aneurysm following flow diversion: mechanical stretch as a potential mechanism for early aneurysm rupture.

    PubMed

    Fox, Benjamin; Humphries, William Edward; Doss, Vinodh T; Hoit, Daniel; Elijovich, Lucas; Arthur, Adam S

    2015-11-01

    A patient with a giant symptomatic vertebrobasilar aneurysm was treated by endoscopic third ventriculostomy for obstructive hydrocephalus followed by treatment of the aneurysm by flow diversion using a Pipeline Embolization Device. After an uneventful procedure and initial periprocedural period, the patient experienced an unexpected fatal subarachnoid hemorrhage 1 week later. Autopsy demonstrated extensive subarachnoid hemorrhage and aneurysm rupture (linear whole wall rupture). The patent Pipeline Embolization Device was in its intended location, as was the persistent coil occlusion of the distal left vertebral artery. The aneurysm appeared to rupture in a linear manner and contained a thick large expansile clot that seemed to disrupt or rupture the thin aneurysm wall directly opposite the basilar artery/Pipeline Embolization Device. We feel the pattern of aneurysm rupture in our patient supports the idea that the combination of flow diversion and the resulting growing intra-aneurysmal thrombus can create a mechanical force with the potential to cause aneurysm rupture. PMID:25361560

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

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1978-01-01

    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.

  1. [Successive ruptures of patellar and Achilles tendons. Anabolic steroids in competitive sports].

    PubMed

    Isenberg, J; Prokop, A; Skouras, E

    2008-01-01

    Derivatives of testosterone or of 19-nor-testosterone are used as anabolics for the purpose of improving performance although the effect of anabolics is known still to be under discussion. The use of anabolic steroids continues among competitive athletes despite increased controls and increasingly frequent dramatic incidents connected with them. Whereas metabolic dysfunction during anabolic use is well documented, ruptures of the large tendons are rarely reported. Within 18 months, a 29-year-old professional footballer needed surgery for rupture of the patellar tendon and of both Achilles tendons. Carefully directed questioning elicited confirmation that he had taken different anabolic steroids regularly for 3 years with the intention of improving his strength. After each operation anabolic steroids were taken again at a high dosage during early convalescence and training. Minimally invasive surgery and open suturing techniques led to complete union of the Achilles tendons in good time. Training and anabolic use (metenolon 300 mg per week) started early after suturing of the patellar tendon including bone tunnels culminated in histologically confirmed rerupture after 8 weeks. After a ligament reconstruction with a semitendinosus tendon graft with subsequent infection, the tendon and reserve traction apparatus were lost. Repeated warnings of impaired healing if anabolic use was continued had been given without success. In view of the high number of unrecorded cases in competitive and athletic sports, we can assume that the use of anabolic steroids is also of quantitative relevance in the operative treatment of tendon ruptures.

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

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2010-01-01

    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.

  3. A generic model for creep rupture lifetime estimation on fibrous ceramic composites

    NASA Technical Reports Server (NTRS)

    Chuang, Tze-Jer

    1992-01-01

    Because of their high strength and toughness at elevated temperatures, fiber reinforced ceramic composites such as SiC(f)/SiC and SiC(f)/Si3N4 have become candidates for next-generation turbine engine materials. A generic model is proposed for assessing the lifetime of this class of materials when subjected to long-term creep rupture conditions. This 2D model consists of interfacial cracks growing between square grains and rectangular fibers in the direction normal to the principal tensile stress axis. Neglecting transient effects, the total lifetime is derived based on the criterion that rupture is due to coalescence of adjacent cracks. Lifetime is inversely proportional to crack growth rate, volume fraction, and aspect ratio of the fibers; but extremely sensitive to the applied stress, due to the high power of the V-K(I) law. This lifetime estimation seems to be in fair agreement with the creep rupture data of SiC(w)/Si3N4 composite with 0 and 30 vol percent reinforcement tested at 1250 C in air. TEM performed on the postcrept specimens revealed that creep damage is predominantly in the form of microcracks at matrix/matrix as well as fiber/matrix interfaces, approximately in accord with the model simulation.

  4. Carpal tunnel release with subneural reconstruction of the transverse carpal ligament compared with isolated open and endoscopic release.

    PubMed

    Zhang, X; Li, Y; Wen, S; Zhu, H; Shao, X; Yu, Y

    2015-02-01

    We report a new surgical technique of open carpal tunnel release with subneural reconstruction of the transverse carpal ligament and compare this with isolated open and endoscopic carpal tunnel release. Between December 2007 and October 2011, 213 patients with carpal tunnel syndrome (70 male, 143 female; mean age 45.6 years; 29 to 67) were recruited from three different centres and were randomly allocated to three groups: group A, open carpal tunnel release with subneural reconstruction of the transverse carpal ligament (n = 68); group B, isolated open carpal tunnel release (n = 92); and group C, endoscopic carpal tunnel release (n = 53). At a mean final follow-up of 24 months (22 to 26), we found no significant difference between the groups in terms of severity of symptoms or lateral grip strength. Compared with groups B and C, group A had significantly better functional status, cylindrical grip strength and pinch grip strength. There were significant differences in Michigan Hand Outcome scores between groups A and B, A and C, and B and C. Group A had the best functional status, cylindrical grip strength, pinch grip strength and Michigan Hand Outcome score. Subneural reconstruction of the transverse carpal ligament during carpal tunnel decompression maximises hand strength by stabilising the transverse carpal arch. PMID:25628286

  5. The repetition of large-earthquake ruptures.

    PubMed Central

    Sieh, K

    1996-01-01

    This survey of well-documented repeated fault rupture confirms that some faults have exhibited a "characteristic" behavior during repeated large earthquakes--that is, the magnitude, distribution, and style of slip on the fault has repeated during two or more consecutive events. In two cases faults exhibit slip functions that vary little from earthquake to earthquake. In one other well-documented case, however, fault lengths contrast markedly for two consecutive ruptures, but the amount of offset at individual sites was similar. Adjacent individual patches, 10 km or more in length, failed singly during one event and in tandem during the other. More complex cases of repetition may also represent the failure of several distinct patches. The faults of the 1992 Landers earthquake provide an instructive example of such complexity. Together, these examples suggest that large earthquakes commonly result from the failure of one or more patches, each characterized by a slip function that is roughly invariant through consecutive earthquake cycles. The persistence of these slip-patches through two or more large earthquakes indicates that some quasi-invariant physical property controls the pattern and magnitude of slip. These data seem incompatible with theoretical models that produce slip distributions that are highly variable in consecutive large events. Images Fig. 3 Fig. 7 Fig. 9 PMID:11607662

  6. Probability of rupture of multiple fault segments

    USGS Publications Warehouse

    Andrews, D.J.; Schwerer, E.

    2000-01-01

    Fault segments identified from geologic and historic evidence have sometimes been adopted as features limiting the likely extends of earthquake ruptures. There is no doubt that individual segments can sometimes join together to produce larger earthquakes. This work is a trial of an objective method to determine the probability of multisegment ruptures. The frequency of occurrence of events on all conjectured combinations of adjacent segments in northern California is found by fitting to both geologic slip rates and to an assumed distribution of event sizes for the region as a whole. Uncertainty in the shape of the distribution near the maximum magnitude has a large effect on the solution. Frequencies of individual events cannot be determined, but it is possible to find a set of frequencies to fit a model closely. A robust conclusion for the San Francisco Bay region is that large multisegment events occur on the San Andreas and San Gregorio faults, but single-segment events predominate on the extended Hayward and Calaveras strands of segments.

  7. Transverse-Type Short-Circuited Thermoelements

    NASA Astrophysics Data System (ADS)

    Anatychuk, L. I.; Kobylyansky, R. R.

    2012-06-01

    This work reports on the results of theoretical and experimental research of short-circuited thermoelements (SCTE). Computer simulation was used to obtain the electric potential, current, and temperature distributions in the bulk of thermoelements. Computer optimization of such a thermoelement design was carried out to achieve maximum transverse thermoelectromotive force (thermoEMF) and efficiency. Experimental studies of the short-circuited thermoelements were pursued. Bi-Te alloys were used as the thermoelectric material. It was established that, among the transverse-type thermoelements, double short-circuited thermoelements achieve the highest values of transverse thermoEMF and efficiency.

  8. Transverse Emittance Reduction with Tapered Foil

    SciTech Connect

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

    2011-12-09

    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

  9. Transverse Colon Diverticulitis with Calcified Fecalith

    PubMed Central

    Solak, Aynur; Solak, Ilhami; Genç, Berhan; Sahin, Neslin; Yalaz, Seyhan

    2013-01-01

    Left colonic diverticula are common in Western populations, whereas right colonic diverticulosis primarily occurs in Oriental populations. Diverticulitis of the transverse colon is very rare, with very few cases reported in the literature. Herein, we report a case of transverse colon diverticulitis caused by a calcified stone in a 69-year-old female. This was a solitary diverticulum. The signs and symptoms of the disease are similar to acute pancreatitis. To the best of our knowledge, this is the first report describing the MRI findings of a patient with trans-verse colon diverticulitis caused by a calcified stone. PMID:25610254

  10. Ferroelectric Cathodes in Transverse Magnetic Fields

    SciTech Connect

    Alexander Dunaevsky; Yevgeny Raitses; Nathaniel J. Fisch

    2002-07-29

    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.

  11. Clinical outcomes after repair of quadriceps tendon rupture: a systematic review.

    PubMed

    Ciriello, Vincenzo; Gudipati, Suribabu; Tosounidis, Theodoros; Soucacos, P N; Giannoudis, Peter V

    2012-11-01

    The existing evidence regarding the management of quadriceps tendon rupture remains obscure. The aim of the current review is to investigate the characteristics, the different techniques employed and to analyse the clinical outcomes following surgical repair of quadriceps tendon rupture. An Internet based search of the English literature of the last 25 years was carried out. Case reports and non-clinical studies were excluded. The methodological quality of the included studies was assessed using the Coleman Methodology Score. All data regarding mechanism and site of rupture, type of treatment, time elapsed between diagnosis and repair, patients' satisfaction, clinical outcome, return to pre-injury activities, complications and recurrence rates were extracted and analysed. Out of 474 studies identified, 12 met the inclusion criteria. The average of Coleman Methodology Score was 50.46/100. In total 319 patients were analysed with a mean age of 57 years (16-85). The mean time of follow-up was 47.5 months (3 months to 24 years). The most common mechanism of injury was simple fall (61.5%). Spontaneous ruptures were reported in 3.2% of cases. The most common sites of tear were noted between 1cm and 2 cm of the superior pole of the patella and, in the older people, at the osseotendinous junction. The most frequently used repair technique was patella drill holes (50% of patients). Simple sutures were used in mid-substance ruptures. Several reinforcement techniques were employed in case of poor quality or retraction of the torn ends of tendon. The affected limb was immobilised in a cast for a period of 3-10 weeks. Quadriceps muscular atrophy and muscle strength deficit were present in most of the cases. Worst results were noted in delayed repairs. Reported complications included heterotopic ossifications in 6.9% of patients, deep venous thrombosis or pulmonary embolism in 2.5%, superficial infection in 1.2% and deep infection in 1.1%. It appears that the type of surgical

  12. Extraperitoneally Ruptured, Everted, and Prolapsed Bladder: A Very Rare Complication of Pelvic Injury.

    PubMed

    Ojewola, Rufus Wale; Tijani, Kehinde Habeeb; Badmus, Olakunle Olaleke; Oliyide, Abisola Ekundayo; Osegbe, Chukwudi Emmanuel

    2015-01-01

    Traumatic rupture of the bladder with eversion and protrusion via the perineum is a rare complication of pelvic injury. We present a 36-year-old lady who sustained severe pelvic injury with a bleeding right-sided deep perineal laceration. She had closed reduction of pelvic fracture with pelvic banding and primary closure of perineal laceration at a private hospital. She subsequently had dehiscence of repaired perineal laceration with protrusion of fleshy mass from vulva and leakage of urine per perineum five weeks later. Examination revealed a fleshy mucosa-like mass protruding anteriorly with a bridge of tissue between it and right anterolateral vaginal wall. Upward pressure on this mass revealed the bladder neck and ureteric orifices. She had perineal and pelvic exploration with findings of prolapsed, completely everted bladder wall through a transverse anterior bladder wall rent via the perineum, and an unstable B1 pelvic disruption. She had repair of the ruptured, everted, and prolapsed bladder, double-plate and screw fixation of disrupted pelvis and repair of the pelvic/perineal defect. She commenced physiotherapy and ambulation a week after surgery. Patient now walks normally and is continent of urine. We conclude that the intrinsic urethral continent mechanism plays a significant role in maintaining continence in females. PMID:26417472

  13. Extraperitoneally Ruptured, Everted, and Prolapsed Bladder: A Very Rare Complication of Pelvic Injury

    PubMed Central

    Ojewola, Rufus Wale; Tijani, Kehinde Habeeb; Badmus, Olakunle Olaleke; Oliyide, Abisola Ekundayo; Osegbe, Chukwudi Emmanuel

    2015-01-01

    Traumatic rupture of the bladder with eversion and protrusion via the perineum is a rare complication of pelvic injury. We present a 36-year-old lady who sustained severe pelvic injury with a bleeding right-sided deep perineal laceration. She had closed reduction of pelvic fracture with pelvic banding and primary closure of perineal laceration at a private hospital. She subsequently had dehiscence of repaired perineal laceration with protrusion of fleshy mass from vulva and leakage of urine per perineum five weeks later. Examination revealed a fleshy mucosa-like mass protruding anteriorly with a bridge of tissue between it and right anterolateral vaginal wall. Upward pressure on this mass revealed the bladder neck and ureteric orifices. She had perineal and pelvic exploration with findings of prolapsed, completely everted bladder wall through a transverse anterior bladder wall rent via the perineum, and an unstable B1 pelvic disruption. She had repair of the ruptured, everted, and prolapsed bladder, double-plate and screw fixation of disrupted pelvis and repair of the pelvic/perineal defect. She commenced physiotherapy and ambulation a week after surgery. Patient now walks normally and is continent of urine. We conclude that the intrinsic urethral continent mechanism plays a significant role in maintaining continence in females. PMID:26417472

  14. Dynamic earthquake rupture simulation on nonplanar faults embedded in 3D geometrically complex, heterogeneous Earth models

    NASA Astrophysics Data System (ADS)

    Duru, K.; Dunham, E. M.; Bydlon, S. A.; Radhakrishnan, H.

    2014-12-01

    Dynamic propagation of shear ruptures on a frictional interface is a useful idealization of a natural earthquake.The conditions relating slip rate and fault shear strength are often expressed as nonlinear friction laws.The corresponding initial boundary value problems are both numerically and computationally challenging.In addition, seismic waves generated by earthquake ruptures must be propagated, far away from fault zones, to seismic stations and remote areas.Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods.We present a numerical method for:a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration;b) dynamic propagation of earthquake ruptures along rough faults; c) accurate propagation of seismic waves in heterogeneous media with free surface topography.We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts finite differences in space. The finite difference stencils are 6th order accurate in the interior and 3rd order accurate close to the boundaries. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. Time stepping is performed with a 4th order accurate explicit low storage Runge-Kutta scheme. We have performed extensive numerical experiments using a slip-weakening friction law on non-planar faults, including recent SCEC benchmark problems. We also show simulations on fractal faults revealing the complexity of rupture dynamics on rough faults. We are presently extending our method to rate-and-state friction laws and off-fault plasticity.

  15. Development of Transverse Modes Damped DLA Structure

    SciTech Connect

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

    2009-01-22

    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.

  16. Transverse damping systems in modern synchrotrons

    NASA Astrophysics Data System (ADS)

    Zhabitsky, V. M.

    2006-12-01

    Transverse feedback systems for suppression of transverse coherent beam oscillations are used in modern synchrotrons for preventing the development of transverse instabilities and damping residual beam oscillations after injection. Information on damper systems for the Large Hadron Collider (LHC; CERN, Geneva) and the accelerator complex FAIR (GSI, Darmstadt) is presented. The project for the LHC is being performed at the Laboratory of Particle Physics of the Joint Institute for Nuclear Research in collaboration with CERN. The information concerning the state of the project and the plans of its completion at the LHC is given. The results of the first design activity on transverse damping systems at the SIS100 and SIS300 synchrotrons, to be created in the framework of the new international project FAIR, are presented.

  17. Transversally periodic solitary gravity-capillary waves.

    PubMed

    Milewski, Paul A; Wang, Zhan

    2014-01-01

    When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922

  18. Transversally periodic solitary gravity-capillary waves.

    PubMed

    Milewski, Paul A; Wang, Zhan

    2014-01-01

    When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles.

  19. Chronic Osteomyelitis of the Lumbar Transverse Process

    PubMed Central

    Lee, Bong-Jin; Yoon, Min Geun; Kim, Sung-Soo; Moon, Myung-Sang

    2011-01-01

    Pyogenic spondylitis involving only the posterior element of a vertebra is rare. To the best of our knowledge, there have been no reports of osteomyelitis of the transverse process. We report here on a 45-year-old male with a one month history of swelling associated with lower back pain. The magnetic resonance imaging showed a paraspinal soft tissue mass, and computed tomography revealed a fine osteolytic lesion in the right transverse process of the 5th lumbar spine, and this was all consistent with chronic osteomyelitis. A mixed staphylococcal infection was identified. Open drainage, resection of the transverse process and intravenous injection of anti-staphylococcal antibiotics resolved the back pain and reduced the erythrocyte sedimentation rate to normal. Pyogenic osteomyelitis of the transverse process is extremely rare, which can cause a misdiagnosis or a delayed diagnosis. Careful consideration of this disease is needed when evaluating patients who complain of back pain. PMID:21909475

  20. Spontaneous rupture of the liver presenting as scrotal bruising.

    PubMed

    Vachharajani, A; Paes, B

    2001-05-01

    We describe a case of spontaneous rupture of the liver in a neonate, presenting with features consistent with testicular torsion. Ruptured liver has been well described in neonates following birth trauma, coagulation defects, and Group B Streptococcal infection. The etiology in our case remains undefined. PMID:11414525

  1. Diverse rupture processes in the 2015 Peru deep earthquake doublet.

    PubMed

    Ye, Lingling; Lay, Thorne; Kanamori, Hiroo; Zhan, Zhongwen; Duputel, Zacharie

    2016-06-01

    Earthquakes in deeply subducted oceanic lithosphere can involve either brittle or dissipative ruptures. On 24 November 2015, two deep (606 and 622 km) magnitude 7.5 and 7.6 earthquakes occurred 316 s and 55 km apart. The first event (E1) was a brittle rupture with a sequence of comparable-size subevents extending unilaterally ~50 km southward with a rupture speed of ~4.5 km/s. This earthquake triggered several aftershocks to the north along with the other major event (E2), which had 40% larger seismic moment and the same duration (~20 s), but much smaller rupture area and lower rupture speed than E1, indicating a more dissipative rupture. A minor energy release ~12 s after E1 near the E2 hypocenter, possibly initiated by the S wave from E1, and a clear aftershock ~165 s after E1 also near the E2 hypocenter, suggest that E2 was likely dynamically triggered. Differences in deep earthquake rupture behavior are commonly attributed to variations in thermal state between subduction zones. However, the marked difference in rupture behavior of the nearby Peru doublet events suggests that local variations of stress state and material properties significantly contribute to diverse behavior of deep earthquakes. PMID:27386585

  2. Diverse rupture processes in the 2015 Peru deep earthquake doublet

    PubMed Central

    Ye, Lingling; Lay, Thorne; Kanamori, Hiroo; Zhan, Zhongwen; Duputel, Zacharie

    2016-01-01

    Earthquakes in deeply subducted oceanic lithosphere can involve either brittle or dissipative ruptures. On 24 November 2015, two deep (606 and 622 km) magnitude 7.5 and 7.6 earthquakes occurred 316 s and 55 km apart. The first event (E1) was a brittle rupture with a sequence of comparable-size subevents extending unilaterally ~50 km southward with a rupture speed of ~4.5 km/s. This earthquake triggered several aftershocks to the north along with the other major event (E2), which had 40% larger seismic moment and the same duration (~20 s), but much smaller rupture area and lower rupture speed than E1, indicating a more dissipative rupture. A minor energy release ~12 s after E1 near the E2 hypocenter, possibly initiated by the S wave from E1, and a clear aftershock ~165 s after E1 also near the E2 hypocenter, suggest that E2 was likely dynamically triggered. Differences in deep earthquake rupture behavior are commonly attributed to variations in thermal state between subduction zones. However, the marked difference in rupture behavior of the nearby Peru doublet events suggests that local variations of stress state and material properties significantly contribute to diverse behavior of deep earthquakes. PMID:27386585

  3. Ruptured renal artery aneurysm: coil packing with GDCs.

    PubMed

    Takeuchi, Misako; Nakata, Manabu; Kawai, Akira; Suzuki, Kazumi; Morita, Tatsuo; Sugimoto, Hideharu

    2012-06-01

    Renal artery aneurysm (RAA) is a relatively uncommon occurrence, but it can be life-threatening when rupture (although rare) occurs. We present the successful endovascular treatment of a ruptured RAA, which was achieved by packing the aneurysm using Guglielmi and interlocking detachable coils.

  4. Diverse rupture processes in the 2015 Peru deep earthquake doublet.

    PubMed

    Ye, Lingling; Lay, Thorne; Kanamori, Hiroo; Zhan, Zhongwen; Duputel, Zacharie

    2016-06-01

    Earthquakes in deeply subducted oceanic lithosphere can involve either brittle or dissipative ruptures. On 24 November 2015, two deep (606 and 622 km) magnitude 7.5 and 7.6 earthquakes occurred 316 s and 55 km apart. The first event (E1) was a brittle rupture with a sequence of comparable-size subevents extending unilaterally ~50 km southward with a rupture speed of ~4.5 km/s. This earthquake triggered several aftershocks to the north along with the other major event (E2), which had 40% larger seismic moment and the same duration (~20 s), but much smaller rupture area and lower rupture speed than E1, indicating a more dissipative rupture. A minor energy release ~12 s after E1 near the E2 hypocenter, possibly initiated by the S wave from E1, and a clear aftershock ~165 s after E1 also near the E2 hypocenter, suggest that E2 was likely dynamically triggered. Differences in deep earthquake rupture behavior are commonly attributed to variations in thermal state between subduction zones. However, the marked difference in rupture behavior of the nearby Peru doublet events suggests that local variations of stress state and material properties significantly contribute to diverse behavior of deep earthquakes.

  5. Antibiotics after preterm premature rupture of the membranes.

    PubMed

    Singh, Katherine; Mercer, Brian

    2011-06-01

    Preterm premature rupture of the membranes remains a common cause of preterm deliveries and neonatal morbidities. The goal of this study is to review the evidence with regard to the antibiotic treatment after preterm premature rupture of the membranes, long-term outcomes related to antibiotic treatment, and possible complications with treatment. Future research goals are also discussed.

  6. The Resolution of Ruptures in the Therapeutic Alliance.

    ERIC Educational Resources Information Center

    Safran, Jeremy D.; Muran, J. Christopher

    1996-01-01

    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…

  7. Spontaneous rupture of a liver hemangioma. A case report.

    PubMed

    Guillén-Paredes, María Pilar; Martínez Fernández, Josefa; Morales González, Álvaro; Pardo-García, José Luis

    2016-07-01

    Spontaneous rupture of a liver hemangioma is a very uncommon disease, but extremely seriousness because it is associated to a 75% of mortality caused by hipovolemic shock. A case of an spontaneous rupture of liver hemangioma, which was previously unknow, is presented. PMID:27659104

  8. Late rupture of extensor pollicis longus after wrist arthroscopy.

    PubMed

    Fortems, Y; Mawhinney, I; Lawrence, T; Trial, I A; Stanley, J K

    1995-06-01

    The first cases of impending rupture of the extensor pollicis longus after wrist arthroscopy are reported and the etiology is compared with extensor pollicis longus ruptures after nondisplaced or minimally displaced Colles fractures. Both cases were treated with extensor indices proprius to extensor pollicis longus transfer with good clinical results. PMID:7632309

  9. Repair of quadriceps tendon ruptures using suture anchors.

    PubMed

    Richards, David P; Barber, F Alan

    2002-01-01

    The repair of ruptured quadriceps tendon is commonly performed by weaving sutures through the ruptured tendon and then attaching the tendon to the bone by passing these sutures through tunnels in the superior patella. This technical note is the first report we are aware of in the English language literature of a technique that uses suture anchors to attach the tendon to bone.

  10. Simultaneous bilateral quadriceps tendon rupture while playing basketball.

    PubMed

    Shah, M; Jooma, N

    2002-04-01

    Simultaneous bilateral quadriceps tendon rupture is an uncommon injury in healthy people and only a few cases have been reported in athletes. This is the first report of a patient with simultaneous bilateral quadriceps tendon rupture incurred while playing basketball. The injury was surgically repaired and the patient had a good functional outcome.

  11. Exploring the transverse spin structure of the nucleon

    SciTech Connect

    D'Alesio, Umberto

    2008-10-13

    We discuss our present understanding of the transverse spin structure of the nucleon and of related properties originating from parton transverse motion. Starting from the transversity distribution and the ways to access it, we then address the role played by spin and transverse momentum dependent (TMD) distributions in azimuthal and transverse single spin asymmetries. The latest extractions of the Sivers, Collins and transversity functions are also presented.

  12. Chiral dynamics and peripheral transverse densities

    SciTech Connect

    Granados, Carlos G.; Weiss, Christian

    2014-01-01

    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.

  13. A Three Year Clinicopathological Study of Cases of Rupture Uterus

    PubMed Central

    Rathod, Setu; Swain, Sujata

    2015-01-01

    Introduction Rupture uterus is a life threatening obstetric complication with serious maternal and fetal side-effects. We report a 3 year (2010-2013) retrospective clinical study of pregnancy with rupture uterus cases attending a tertiary care hospital. Aim The aim of the study was to evaluate the incidence of rupture uterus, incidence as per age, parity, clinical presentations, risk factors, complications and management. Materials and Methods Retrospective data of 74 cases of rupture uterus in SCB Medical college, Cuttack was collected from case records of 26,547 deliveries during a 3 year span (2010-2013). Parameters like cause of rupture, type, site of rupture and outcome were recorded. The collected data was analysed by SPSS software v19. Results Out of 26,547 deliveries during the three year period, there were 74 cases of rupture uterus with an incidence of rupture 1 in 359 (0.28%). The mean age of rupture uterus was 27.4 years. 95.8% were multigravida and majority were referred cases from low socioeconomic status. Only 40.5% had the required minimum of four antenatal visits as recommended by WHO (World Health Organisation). A total of 48.6% of cases with rupture uterus had history of previous Caesarean section. Prolonged labour was present in 75.6% of the cases. Only 12.2% of the cases had history of oxytocin use whereas 9.5% had undergone an operative vaginal delivery. Obstructed labour was the cause in 24.3% of cases, 85.1% had complete rupture. Majority had a rupture in the anterior wall (69%) and 81.1% had rupture in lower segment of uterus. Only 17.6% had broad ligament haematoma, 10.8% colporrhexis and 6.8% had associated bladder injury. Repair was possible in only 39.2% of cases, whereas majority landed up in hysterectomy. Internal iliac ligation was done in 2.7% of cases. Perinatal mortality was 90.5% whereas maternal death was seen in 13.5% cases. One patient developed VVF (vesicovaginal fistula). Duration of hospital stay was upto 14 days in 81

  14. Earthquake rupture dynamics frozen in exhumed ancient faults.

    PubMed

    Di Toro, Giulio; Nielsen, Stefan; Pennacchioni, Giorgio

    2005-08-18

    Most of our knowledge about co-seismic rupture propagation is derived from inversion and interpretation of strong-ground-motion seismograms, laboratory experiments on rock and rock-analogue material, or inferred from theoretical and numerical elastodynamic models. However, additional information on dynamic rupture processes can be provided by direct observation of faults exhumed at the Earth's surface. Pseudotachylytes (solidified friction-induced melts) are the most certain fault-rock indicator of seismicity on ancient faults. Here we show how the asymmetry in distribution and the orientation of pseudotachylyte-filled secondary fractures around an exhumed fault can be used to reconstruct the earthquake rupture directivity, rupture velocity and fracture energy, by comparison with the theoretical dynamic stress field computed around propagating fractures. In particular, the studied natural network of pseudotachylytes is consistent with a dominant propagation direction during repeated seismic events and subsonic rupture propagation close to the Rayleigh wave velocity.

  15. Earthquake rupture stalled by a subducting fracture zone.

    PubMed

    Robinson, D P; Das, S; Watts, A B

    2006-05-26

    We showed that the rupture produced by the great Peru earthquake (moment magnitude 8.4) on 23 June 2001 propagated for approximately 70 kilometers before encountering a 6000-square-kilometer area of fault that acted as a barrier. The rupture continued around this barrier, which remained unbroken for approximately 30 seconds and then began to break when the main rupture front was approximately 200 kilometers from the epicenter. The barrier had relatively low rupture speed, slip, and aftershock density as compared to its surroundings, and the time of the main energy release in the earthquake coincided with the barrier's rupture. We associate this barrier with a fracture zone feature on the subducting oceanic plate.

  16. Material contrast does not predict earthquake rupture propagation direction

    USGS Publications Warehouse

    Harris, R.A.; Day, S.M.

    2005-01-01

    Earthquakes often occur on faults that juxtapose different rocks. The result is rupture behavior that differs from that of an earthquake occurring on a fault in a homogeneous material. Previous 2D numerical simulations have studied simple cases of earthquake rupture propagation where there is a material contrast across a fault and have come to two different conclusions: 1) earthquake rupture propagation direction can be predicted from the material contrast, and 2) earthquake rupture propagation direction cannot be predicted from the material contrast. In this paper we provide observational evidence from 70 years of earthquakes at Parkfield, CA, and new 3D numerical simulations. Both the observations and the numerical simulations demonstrate that earthquake rupture propagation direction is unlikely to be predictable on the basis of a material contrast. Copyright 2005 by the American Geophysical Union.

  17. Transverse pelvic rotation during quiet human stance.

    PubMed

    Günther, Michael; Otto, Daniel; Müller, Otto; Blickhan, Reinhard

    2008-04-01

    The mechanism of two-legged quiet stance is unclear. This study specifically investigated biomechanical parameters characterising the mechanisms of rotation around the longitudinal axis (parallel to gravitational acceleration, i.e. in the transverse plane parallel to the ground). Subjects (10) were examined while standing quietly on two force platforms which measured the transverse component of the ground reaction torque (GRT). In addition, right and left hip kinematics were acquired by tracking markers in the sagittal plane. The pelvic rotation in the transverse plane (pelvic angle) was then calculated from the anterior-posterior coordinates of the hip markers. We verified the hypothesis that the pelvis generally may be coupled to the ground by a rotational stiffness provided by both legs. Thus, we asked whether the transverse GRT component may be proportional to the pelvic angle. This hypothesis was rejected. However, the transverse GRT component could be identified as one rotational stabilising mechanism which drove the higher-frequency (>1 Hz) deflections of the pelvic angle back to its lower-frequency fraction. The respective stiffness coefficient between transverse GRT component and relative displacement between higher- and lower-frequency pelvic angular fraction was about 2.4 Nm/degrees. Implications for the character and the localisation of active control of body rotation around the longitudinal axis are discussed.

  18. Transverse structure of the QCD string

    SciTech Connect

    Meyer, Harvey B.

    2010-11-15

    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.

  19. [Tracheal rupture: delayed diagnosis with endobronchial intubation].

    PubMed

    Besmer, I; Schüpfer, G; Stulz, P; Jöhr, M

    2001-03-01

    Tracheobroncheal rupture is a rare complication of intubation techniques using a stylet. In this case report the patient was intubated by an emergency physician in a preclinical setting after a motor vehicle accident. Iatrogenic tracheal laceration was masked by inappropriate position of the endobronchial tube. By chance ventilation was maintained to both lungs by flow through the Murphy's eye of the tube and the lumen of the tube. In correcting the deep tube position after a chest x-ray laceration of the trachea was unmasked and ventilation problems occurred immediately. The tube was replaced under fiberoptical control and the patient was managed for surgical repair using a jet ventilation technique. In this case two complications of endobronchial intubation occurred, but the deep tube placement opposed the effects of the tracheal laceration. This was probably life saving for the patient during emergency transfer by helicopter after the accident. The anaesthesiological management during tracheal repair is discussed.

  20. Essentials of anterior cruciate ligament rupture management.

    PubMed

    Klinge, Stephen A; Sawyer, Gregory A; Hulstyn, Michael J

    2013-05-01

    Anterior cruciate ligament (ACL) rupture is a common knee injury and an understanding of current medical knowledge regarding its management is essential. Accurate and prompt diagnosis requires an awareness of injury mechanisms and risk factors, common symptoms and physical/radiologic findings. Early mobilization and physical therapy improves outcomes regardless of treatment modality. Many older patients regain sufficient stability and function after non-operative rehabilitation. Early ACL reconstruction is appropriate for younger patients and those who engage in activities requiring frequent pivoting and rapid direction changes. ACL surgery involves reconstruction of the torn ligament tissue with various replacement graft options, each with advantages and disadvantages. The guidance of a knowledgeable and experienced therapist is required throughout an intensive and prolonged rehabilitation course. Generally excellent outcomes and low complication rates are expected, but treatment does not prevent late osteoarthritis.

  1. Can Severe Kyphoscoliosis Lead to Aorta Rupture?

    PubMed

    Kotopoulos, Constantinos; Karakasi, Maria Valeria; Kapetanakis, Stylianos; Pavlidis, Pavlos

    2016-09-01

    Neurofibromatosis type 1 is a polysystemic disease presenting with a multifaceted clinical picture. Clinical manifestations may present in the skin, as well as in the skeletal and cardiovascular system. The present study aims to describe and examine the case of a 46-year-old woman, who suffered from neurofibromatosis type 1 and died abruptly in the emergency room. The forensic examination attributed her death to traumatic rupture of the thoracic aorta resulting from an acute angulation that her vertebral column formed in the thoracic region (severe kyphosis). Outspread cutaneous neurofibromas, severe scoliosis, and osteoporosis (brittle bones) were observed during the autopsy. No atherosclerotic lesions were detected in the aortic lumen. To the authors' knowledge, no similar case has been reported throughout relevant literature. PMID:27323279

  2. [Tendinosis and ruptures of the Achilles tendon].

    PubMed

    Amlang, M H; Zwipp, H

    2012-02-01

    Tendinosis of the Achilles tendon is a degenerative-reparative structural change of the tendon with microdefects, increases in cross-section due to cicatricial tendon regeneration, neoangiogenesis and reduction of elasticity. The previously used term tendinitis is only rarely used for the chronic form since signs of inflammation such as redness and hyperthermia or elevated levels of inflammatory parameters on laboratory testing are generally absent. Duplex sonography with visualization of the neovascularization has become a valuable supplement not only for diagnostics but also for therapy planning. The classic, conservative therapy for painful tendinosis consists of oral anti-inflammatory drugs, pain-adapted load reduction, raising the heel, stretching the calf musculature, and various physiotherapeutic interventions. When conservative treatment over a period of 4 - 6 months fails to produce any or non-adequate pain relief, an indication for surgical treatment should be considered. In the therapy for fresh ruptures of the Achilles tendon further developments in minimally invasive techniques have led to a worldwide paradigm change over the past 10 years. The decisive advantage of minimally invasive surgical techniques is the lower risk of wound infection as compared to the sutures of the open technique. When compared with conservative functional therapy the minimally invasive repair has the advantage of being less dependent on the compliance of the patient since, in the early phase of tendon healing the suture prevents a separation of the tendon ends upon controlled movements. However, not every patient with a ruptured Achilles tendon should be treated with a minimally invasive repair. Open tendon reconstruction and functional conservative therapy are still justified when the correct indication is given. PMID:22344862

  3. Guide to transverse projections and mass-constraining variables

    SciTech Connect

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

    2011-11-01

    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.

  4. Post-Seismic Fault Healing on the Rupture Zone of the 1999 M7.1 Hector Mine, California Earthquake

    NASA Astrophysics Data System (ADS)

    Li, Y.; Vidale, J. E.; Day, S. M.; Oglesby, D. D.; Cochran, E.; Gross, K.; Burdette, T.; Alvarez, M.

    2002-12-01

    We probed the rupture zone of the October 1999 M7.1 Hector Mine earthquake using repeated near-surface explosions in October, 2000 and November, 2001. Three dense linear seismic arrays were deployed across the north and south Lavic Lake faults (LLF) that broke to the surface in the mainshock, and across the Bullion fault (BF) that experienced minor slip in that event. Two explosions each year were detonated in the rupture zone on the middle and south LLF, respectively. We found that P and S velocities of fault-zone rocks increased by ~0.7 to 1.4% and ~0.5 to 1.0% between 2000 and 2001, respectively. In contrast, the velocities for P and S waves in surrounding rocks increased much less. This trend indicates the Hector Mine rupture zone has been healing by strengthening after the mainshock, which we attribute to the closure of cracks that opened during the 1999 earthquake. The 'crack dilatancy' mechanisms are most likely to operate for fault healing at shallow depth although the healing may be controlled by a combination of mechanical and chemical processes on the fault during the earthquake cycle. The observed fault-zone strength recovery is consistent with an apparent crack density decrease of 1.5% within the rupture zone. The ratio of travel time decrease for P to S waves was 0.72, consistent with partially fluid-filled cracks near the fault zone were. We also find variability in healing rates between the fault segments. The velocity increase with time varies from one fault segment to another at the Hector Mine rupture zone. We see greater changes on the LLF than on the BF, and the greatest change is on the middle LLF at shallow depth. We speculate that greater damage was inflicted, and thus greater healing is observed, in regions with larger slip in the mainshock. This post-seismic restrengthening of the Hector Mine rupture zone is similar to that observed on the Johnson Valley fault which ruptured in the 1992 M7.4 Landers earthquake (Li and Vidale, GRL, 2001

  5. P-wave signatures and parameterization of transversely isotropic media: An overview

    SciTech Connect

    Tsvankin, I.

    1994-07-01

    Progress in seismic inversion and processing in anisotropic media depends on our ability to relate different seismic signatures to the anisotropic parameters. While the conventional notation (stiffness coefficients) is suitable for forward modeling, it is inconvenient in developing analytic insight into the influence of anisotropy on wave propagation. The author gives a consistent description of P-wave signatures in transversely isotropic media with arbitrary strength of the anisotropy, using the notation suggested by Thomsen (1986). The influence of transverse isotropy on P-wave propagation is shown to be practically independent of the vertical S-wave velocity V{sub S0}, even in models with strong velocity variations. Therefore, the contribution of transverse isotropy to P-wave kinematic and dynamic signatures is controlled by just two anisotropic parameters, {epsilon} and {delta}, with the vertical velocity V{sub P0} being no more than a scaling coefficient in homogeneous models.

  6. Complete Transversal Disc Fracture in a Björk-Shiley Delrin Mitral Valve Prosthesis 43 Years After Implantation.

    PubMed

    González-Santos, Jose María; Arnáiz-García, María Elena; Dalmau-Sorlí, María José; Sastre-Rincón, Jose Alfonso; Hernández-Hernández, Jesús; Pérez-Losada, María Elena; Sagredo-Meneses, Víctor; López-Rodríguez, Javier

    2016-10-01

    A patient who underwent previous implantation of a mitral valve replacement with a Björk-Shiley Delrin (BSD) mitral valve prosthesis during infancy was admitted to our institution 43 years later after an episode of syncope and cardiac arrest. Under extreme hemodynamic instability, a mitral valve prosthetic dysfunction causing massive mitral regurgitation was identified. The patient underwent an emergent cardiac operation, and a complete disc fracture with partial disc migration was found. Exceptional cases of mechanical prosthetic heart valve fracture exist. We report the first case of complete transversal disc rupture of a BSD mitral valve prosthesis after the longest period of implantation ever reported in that position. PMID:27645963

  7. Transverse and longitudinal angular momenta of light

    NASA Astrophysics Data System (ADS)

    Bliokh, Konstantin Y.; Nori, Franco

    2015-08-01

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin-direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties.

  8. Transverse beam emittance measurement using quadrupole variation at KIRAMS-430

    NASA Astrophysics Data System (ADS)

    An, Dong Hyun; Hahn, Garam; Park, Chawon

    2015-02-01

    In order to produce a 430 MeV/u carbon ion (12 C 6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.

  9. Larmor frequency dressing by a nonharmonic transverse magnetic field

    NASA Astrophysics Data System (ADS)

    Bevilacqua, G.; Biancalana, V.; Dancheva, Y.; Moi, L.

    2012-04-01

    We present a theoretical and experimental study of spin precession in the presence of both a static and an orthogonal oscillating magnetic field, which is nonresonant, not harmonically related to the Larmor precession, and of arbitrary strength. Due to the intrinsic nonlinearity of the system, previous models that account only for the simple sinusoidal case cannot be applied. We suggest an alternative approach and develop a model that closely agrees with experimental data produced by an optical-pumping atomic magnetometer. We demonstrate that an appropriately designed nonharmonic field makes it possible to extract a linear response to a weak dc transverse field, despite the scalar nature of the magnetometer, which normally causes a much weaker, second-order response.

  10. Single-knob beam line for transverse emittance partitioning

    NASA Astrophysics Data System (ADS)

    Xiao, C.; Kester, O. K.; Groening, L.; Leibrock, H.; Maier, M.; Rottländer, P.

    2013-04-01

    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 (αx,y and βx,y) in both planes. It is shown that this single knob is the solenoid field strength.

  11. High strength nickel-chromium-iron austenitic alloy

    DOEpatents

    Gibson, Robert C.; Korenko, Michael K.

    1980-01-01

    A solid solution strengthened Ni-Cr-Fe alloy capable of retaining its strength at high temperatures and consisting essentially of 42 to 48% nickel, 11 to 13% chromium, 2.6 to 3.4% niobium, 0.2 to 1.2% silicon, 0.5 to 1.5% vanadium, 2.6 to 3.4% molybdenum, 0.1 to 0.3% aluminum, 0.1 to 0.3% titanium, 0.02 to 0.05% carbon, 0.002 to 0.015% boron, up to 0.06 zirconium, and the balance iron. After solution annealing at 1038.degree. C. for one hour, the alloy, when heated to a temperature of 650.degree. C., has a 2% yield strength of 307 MPa, an ultimate tensile strength of 513 MPa and a rupture strength of as high as 400 MPa after 100 hours.

  12. Preliminary evaluation of tensile and stress-rupture behavior of W + 24 at. pct Re + 0.4 at. pct HfC wire

    NASA Technical Reports Server (NTRS)

    Yun, H. M.

    1993-01-01

    Results are presented of an evaluation of tensile properties and stress-rupture bahavior of a small-diameter W24ReHfC (W-24Re-0.4(HfC)) wire, which is considered to be an excellent reinforcing fiber candidate for a variety of metal-matrix composites. The results were compared to data of Petrasek (1972) on W4ReHfC (W-4Re-0.4(HfC)) wire. It was found that the room-temperature (RT) tensile strength of the W24ReHfC wire was about 3250 MPa, higher than that of the W4ReHfC (3160 MPa) and WHfC (2250 MPa) wires. Above 1366 K, the W4ReHfC wire had both a greater tensile strength and the stress rupture strength than the W24ReHfC wire.

  13. Cryogenic oxygen jet response to transverse acoustic excitation with the first transverse and the first combined longitudinal-transverse modes

    NASA Astrophysics Data System (ADS)

    Hardi, J. S.; Oschwald, M.

    2016-07-01

    The intact length of the dense oxygen core from an oxygen-hydrogen shear coaxial rocket injector was measured. The measurements were made in a rectangular rocket combustor with optical access and acoustic forcing. The combustor was operated at chamber pressures of 40 and 60 bar, with either ambient temperature or cryogenic hydrogen. The multielement injection spray is subjected to forced transverse gas oscillations of two different acoustic resonance modes; the first transverse (1T) mode at 4200 Hz and the first combined longitudinal-transverse (1L1T) at 5500 Hz. Intact core length is measured from high-speed shadowgraph imaging. The dependence of intact core length with increasing acoustic amplitude is compared for the two modes of excitation.

  14. Factors Controlling Stress Rupture of Fiber-Reinforced Ceramic Composites

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    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.

  15. Daughter bubble cascades produced by folding of ruptured thin films.

    PubMed

    Bird, James C; de Ruiter, Riëlle; Courbin, Laurent; Stone, Howard A

    2010-06-10

    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.

  16. Effect of Time-dependent Rupture on Tsunami Generation

    NASA Astrophysics Data System (ADS)

    Arcas, D.; Kanoglu, U.; Moore, C. W.; Aydin, B.

    2013-12-01

    Differential GPS data from the recent Chile 2009 and Japan 2011 seismic events have unveiled complex time-dependent ground motion dynamics during seismic rupture. Current tsunami modeling techniques usually ignore this time-dependent behavior in tsunami sources by assuming an instantaneous initial deformation field. Initial attempts to include time-dependent rupture behavior have motivated scientists to simulate this phenomenon as a series of instantaneous changes in the sea-floor. The present study investigates the effect of dynamic ground motion rupture on tsunami generation by including the time-dependent initial conditions in the derivation of the linear shallow-water wave equations. We then study the sensitivity of initial water surface deformation to time-dependent seafloor rupture by performing a parametric study of varying speed and rupture direction, while assuming a monotonic deformation from an initial pre-rupture state to a post-rupture final state. Numerical results for some selected scenarios are validated by comparing with analytical solutions of the non-homogeneous linear shallow-water equations.

  17. Daughter bubble cascades produced by folding of ruptured thin films.

    PubMed

    Bird, James C; de Ruiter, Riëlle; Courbin, Laurent; Stone, Howard A

    2010-06-10

    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

  18. Patient specific stress and rupture analysis of ascending thoracic aneurysms.

    PubMed

    Trabelsi, Olfa; Davis, Frances M; Rodriguez-Matas, Jose F; Duprey, Ambroise; Avril, Stéphane

    2015-07-16

    An ascending thoracic aortic aneurysm (ATAA) is a serious medical condition which, more often than not, requires surgery. Aneurysm diameter is the primary clinical criterion for determining when surgical intervention is necessary but, biomechanical studies have suggested that the diameter criterion is insufficient. This manuscript presents a method for obtaining the patient specific wall stress distribution of the ATAA and the retrospective rupture risk for each patient. Five human ATAAs and the preoperative dynamic CT scans were obtained during elective surgeries to replace each patient's aneurysm with a synthetic graft. The material properties and rupture stress for each tissue sample were identified using bulge inflation tests. The dynamic CT scans were used to generate patient specific geometries for a finite element (FE) model of each patient's aneurysm. The material properties from the bulge inflation tests were implemented in the FE model and the wall stress distribution at four different pressures was estimated. Three different rupture risk assessments were compared: the maximum diameter, the rupture risk index, and the overpressure index. The peak wall stress values for the patients ranged from 28% to 94% of the ATAA's failure stress. The rupture risk and overpressure indices were both only weakly correlated with diameter (ρ=-0.29, both cases). In the future, we plan to conduct a large experimental and computational study that includes asymptomatic patients under surveillance, patients undergoing elective surgery, and patients who have experienced rupture or dissection to determine if the rupture risk index or maximum diameter can meaningfully differentiate between the groups. PMID:25979384

  19. Rupture of the uterus in Malawi and Tanzania.

    PubMed

    Armon, P J

    1977-09-01

    This paper describes the presenting features and possible etiology of 115 cases of rupture of the uterus occurring in Malawi and Tanzania. The series included 62 spontaneous ruptures, 24 traumatic ruptures, and 29 scar ruptures. The rupture was complete in 100 cases but the peritoneum was intact in 15. 72 cases involved obstructed labor and 29 occurred in women with previous cesarean sections. Only 22% of subjects were grand multiparae (7 or more pregnancies), and the average parity was 4.5. Classical symptoms and signs either did not occur or were late in appearing in most cases, and none of the women complained of a tearing or bursting sensation. 23 of the cases died during treatment. Sterilization is recommended in cases where the initial rupture extends into or is primarily situated in the upper segment of the uterus due to the probability of recurrence. Delays in reaching medical care and a lack of medical facilities contribute to the incidence of uterine rupture in developing countries. Careful screening for at-riskmothers and use of partograms to diagnose cephalopelvic disproportion during labor would diminish the occurrence of this complication, however. Also recommended is avoidance of unnecessary cesarean section procedures and extreme caution in the management of patients with uterine scars. The limitation of family size and improvements in maternal haalth education are further important preventive measures.

  20. Interaction of dynamic rupture with small-scale heterogeneities

    NASA Astrophysics Data System (ADS)

    Galis, Martin; Mai, P. Martin

    2014-05-01

    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.

  1. Composite impact strength improvement through a fiber/matrix interphase

    NASA Technical Reports Server (NTRS)

    Cavano, P. J.; Winters, W. E.

    1975-01-01

    Research was conducted to improve the impact strength and toughness of fiber/resin composites by means of a fiber coating interphase. Graphite fiber/epoxy resin composites were fabricated with four different fiber coating systems introduced in a matrix-fiber interphase. Two graphite fibers, a high strength and a high modulus type, were studied with the following coating systems: chemical vapor deposited boron, electroless nickel, a polyamide-imide resin and a thermoplastic polysulfone resin. Evaluation methods included the following tests: Izod, flexure, shear fracture toughness, longitudinal and transverse tensile, and transverse and longitudinal compression. No desirable changes could be effected with the high strength fiber, but significant improvements in impact performance were observed with the polyamide-imide resin coated high modulus fiber with no loss in composite modulus.

  2. Nucleon Spin Structure: Longitudinal and Transverse

    SciTech Connect

    Jian-Ping Chen

    2011-02-01

    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.

  3. Stability and conductivity of self assembled wires in a transverse electric field.

    PubMed

    Stephenson, C; Hubler, A

    2015-01-01

    Self assembling wire networks typically evolve to minimize the resistance across electrical contacts which are frequently used in a manner comparable to Hebbian learning. In this work, we demonstrate that electrical fields can also be used to cause an increase in the resistance of the wire network. We show that if such a wire is exposed to a transverse electric field, the wire is deformed in a way that depends on it's tensile strength. We measure the wire resistance as a function of transverse field for several field strengths and show that by deforming the wire, the amplitude of the resulting shape can be modified in a controllable fashion. At a critical value of the transverse field, we show that the wire loses stability. At this point we observe thresholding behavior in that the resistance increases abruptly to a maximum value and the wire is destroyed. This thresholding behavior suggests that self assembled wires may be manipulated via an transverse electric field and demonstrates that a mechanism exists for the destruction of undesirable connections.

  4. Stability and conductivity of self assembled wires in a transverse electric field

    PubMed Central

    Stephenson, C.; Hubler, A.

    2015-01-01

    Self assembling wire networks typically evolve to minimize the resistance across electrical contacts which are frequently used in a manner comparable to Hebbian learning. In this work, we demonstrate that electrical fields can also be used to cause an increase in the resistance of the wire network. We show that if such a wire is exposed to a transverse electric field, the wire is deformed in a way that depends on it’s tensile strength. We measure the wire resistance as a function of transverse field for several field strengths and show that by deforming the wire, the amplitude of the resulting shape can be modified in a controllable fashion. At a critical value of the transverse field, we show that the wire loses stability. At this point we observe thresholding behavior in that the resistance increases abruptly to a maximum value and the wire is destroyed. This thresholding behavior suggests that self assembled wires may be manipulated via an transverse electric field and demonstrates that a mechanism exists for the destruction of undesirable connections. PMID:26463476

  5. Rupture Synchronicity in Complex Fault Systems

    NASA Astrophysics Data System (ADS)

    Milner, K. R.; Jordan, T. H.

    2013-12-01

    While most investigators would agree that the timing of large earthquakes within a fault system depends on stress-mediated interactions among its elements, much of the debate relevant to time-dependent forecasting has been centered on single-fault concepts, such as characteristic earthquake behavior. We propose to broaden this discussion by quantifying the multi-fault concept of rupture synchronicity. We consider a finite set of small, fault-spanning volumes {Vk} within a fault system of arbitrary (fractal) complexity. We let Ck be the catalog of length tmax comprising Nk discrete times {ti(k)} that mark when the kth volume participates in a rupture of magnitude > M. The main object of our analysis is the complete set of event time differences {τij(kk') = ti(k) - tj(k')}, which we take to be a random process with an expected density function ρkk'(t). When k = k', we call this function the auto-catalog density function (ACDF); when k ≠ k', we call it the cross-catalog density function (CCDF). The roles of the ACDF and CCDF in synchronicity theory are similar to those of autocorrelation and cross-correlation functions in time-series analysis. For a renewal process, the ACDF can be written in terms of convolutions of the interevent-time distribution, and many of its properties (e.g., large-t asymptote) can be derived analytically. The interesting information in the CCDF, like that in the ACDF, is concentrated near t = 0. If two catalogs are completely asynchronous, the CCDF collapses to an asymptote given by the harmonic mean of the ACDF asymptotes. Synchronicity can therefore be characterized by the variability of the CCDF about this asymptote. The brevity of instrumental catalogs makes the identification of synchronicity at large M difficult, but we will illustrate potentially interesting behaviors through the analysis of a million-year California catalog generated by the earthquake simulator, RSQSim (Deiterich & Richards-Dinger, 2010), which we sampled at a

  6. Flexibility and Muscular Strength.

    ERIC Educational Resources Information Center

    Liemohn, Wendell

    1988-01-01

    This definition of flexibility and muscular strength also explores their roles in overall physical fitness and focuses on how increased flexibility and muscular strength can help decrease or eliminate lower back pain. (CB)

  7. Ruptured ileocolic artery aneurysm: an unusual cause of hemoperitoneum.

    PubMed

    Siddiqui, Zakaur R; Yousif, Omer F; Halliday, Mark W; Hubaishah, Nasser A; Adam, Khalid A

    2012-01-01

    Ruptured aneurysm of a branch of ileocolic artery is a rare finding and is an unusual cause of haemoperitoneum. Rapid diagnosis, and surgical or endovascular intervention are necessary to avoid devastating consequences and high mortality rates following an emergency operation after rupture. Resection is a good choice for surgical intervention for some aneurysms that are not suitable for endovascular repair. This report describes the case of a middle-aged man with a ruptured superior mesenteric artery branch aneurysm and his subsequent surgical management. PMID:23006464

  8. Ruptured Ileocolic Artery Aneurysm: An Unusual Cause of Hemoperitoneum

    PubMed Central

    Siddiqui, Zakaur R.; Yousif, Omer F.; Halliday, Mark W.; Hubaishah, Nasser A.; Adam, Khalid A.

    2012-01-01

    Ruptured aneurysm of a branch of ileocolic artery is a rare finding and is an unusual cause of haemoperitoneum. Rapid diagnosis, and surgical or endovascular intervention are necessary to avoid devastating consequences and high mortality rates following an emergency operation after rupture. Resection is a good choice for surgical intervention for some aneurysms that are not suitable for endovascular repair. This report describes the case of a middle-aged man with a ruptured superior mesenteric artery branch aneurysm and his subsequent surgical management. PMID:23006464

  9. MRI diagnosis of spontaneous uterine rupture of an unscarred uterus.

    PubMed

    Hruska, Karim M; Coughlin, Bret F; Coggins, Allahna A; Wiczyk, Halina P

    2006-05-01

    Spontaneous uterine rupture is a rare, potentially catastrophic complication of pregnancy, and its prompt diagnosis and treatment are essential in limiting morbidity and mortality. Clinical diagnosis is difficult and relies heavily on diagnostic imaging. Radiological diagnosis is also often difficult with most documented cases involving the use of ultrasound and computed tomography. Although magnetic resonance imaging (MRI) is being used more frequently to assess patients, there are few reports illustrating the utility of MRI and its advantages over other imaging modalities in the diagnosis of uterine rupture. This report documents a case of spontaneous uterine rupture diagnosed by MRI in a postpartum patient with an unscarred uterus.

  10. Spontaneous Uterine Rupture of an Unscarred Uterus before Labour.

    PubMed

    Guèye, Mamour; Mbaye, Magatte; Ndiaye-Guèye, Mame Diarra; Kane-Guèye, Serigne Modou; Diouf, Abdoul Aziz; Niang, Mouhamadou Mansour; Diaw, Hannegret; Moreau, Jean Charles

    2012-01-01

    Uterine rupture is a public health problem in developing countries. When it is spontaneous, it occurs most often during labor in a context of scarred uterus. Uterine rupture during pregnancy is a rare situation. The diagnosis is not always obvious and morbidity and maternal and fetal mortality is still high. We report a case of spontaneous uterine rupture during pregnancy at 35 weeks of an unscarred uterus before labour. This is an exceptional case that we observe for the first time in our unit.

  11. Uterine rupture at 10 weeks of gestation after laparoscopic myomectomy.

    PubMed

    Okada, Yoshiyuki; Hasegawa, Junichi; Mimura, Takashi; Arakaki, Tatsuya; Yoshikawa, Shinichiro; Yamashita, Yuka; Oba, Tomohiro; Nakamura, Masamitsu; Matsuoka, Ryu; Sekizawa, Akihiko

    2016-01-01

    The patient had a previous history of laparoscopic myomectomy. At 10 weeks of gestation, she visited our emergency center due to sudden abdominal pain. An ultrasound examination and MRI showed complete rupture of the uterine myometrium in the fundal wall and a floating gestation sac in Douglas' fossa with fluid. Emergency abdominal laparotomy was immediately performed due to the diagnosis of uterine rupture. During surgery, a small defect of the myometrium was found in the posterior fundal wall of the uterus. Two-layer suturing was performed at the perforation hole. The occasional occurrence of uterine rupture after surgery of the uterus even in the first trimester should be considered.

  12. Minimum Energy Path to Membrane Pore Formation and Rupture

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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.

  13. What Is a Strength?

    ERIC Educational Resources Information Center

    Wolin, Sybil

    2003-01-01

    As the strength-based perspective gains recognition, it is important to describe what constitutes strengths and to develop a specific vocabulary to name them. This article draws on resilience research to help identify specific competencies and areas of strengths in youth. (Contains 1 table.)

  14. Strength Training for Girls.

    ERIC Educational Resources Information Center

    Connaughton, Daniel; Connaughton, Angela; Poor, Linda

    2001-01-01

    Strength training can be fun, safe, and appropriate for young girls and women and is an important component of any fitness program when combined with appropriate cardiovascular and flexibility activities. Concerns and misconceptions regarding girls' strength training are discussed, presenting general principles of strength training for children…

  15. Transverse Bursts in Inclined Layer Convection: Experiment

    NASA Astrophysics Data System (ADS)

    Daniels, Karen; Wiener, Richard; Bodenschatz, Eberhard

    2002-03-01

    We report experimental results on inclined layer convection in a fluid of Prandtl number σ ≈ 1. A codimension-two point divides regions of buoyancy-driven convection (longitudinal rolls) at lower angles from shear-driven convection (transverse rolls) at higher angles (Daniels et al. PRL 84: 5320, 2000). In the region of buoyancy-driven convection, near the codimension-two point, we observe longitudinal rolls with intermittent, localized, subharmonic transverse bursts. The patterns are spatiotemporally chaotic. With increasing temperature difference the bursts increase in duration and number. We examine the details of the bursting process (e.g. the energy of longitudinal, transverse, and mixed modes) and compare our results to bursting processes in other systems. This work is supported by the National Science Foundation under grant DMR-0072077 and the IGERT program in nonlinear systems, grant DGE-9870631.

  16. Efficient modeling in transversely isotropic inhomogeneous media

    SciTech Connect

    Alkhalifah, T.

    1993-11-01

    An efficient modeling technique for transversely isotropic, inhomogeneous media, is developed using a mix of analytical equations and numerical calculations. The analytic equation for the raypath in a factorized transversely isotropic (FTI) media with linear velocity variation, derived by Shearer and Chapman, is used to trace between two points. In addition, I derive an analytical equation for geometrical spreading in FTI media that aids in preserving program efficiency; however, the traveltime is calculated numerically. I then generalize the method to treat general transversely isotropic (TI) media that are not factorized anisotropic inhomogeneous by perturbing the FTI traveltimes, following the perturbation ideas of Cerveny and Filho. A Kirchhoff-summation-based program relying on Trorey`s (1970) diffraction method is used to generate synthetic seismograms for such a medium. For the type of velocity models treated, the program is much more efficient than finite-difference and general ray-trace modeling techniques.

  17. Effect of water on long-term weakening preceding rupture of crustal faults

    NASA Astrophysics Data System (ADS)

    Masuda, K.; Arai, T.; Fujimoto, K.; Takahashi, M.; Shigematsu, N.

    2010-12-01

    Fault strength is a critical parameter in studies of crustal mechanics and for the prediction of earthquake hazards. The strengths of crustal faults inferred from borehole heat flow measurements and maximum stress orientations in the crust are less than those determined from laboratory measurements. Suggested causes of the weakening of faults include high fluid pressures, dynamic processes, or the presence of weak fault gouge. However, long-term changes of fault strength cannot be directly monitored using geophysical techniques, so an explanation for fault weakening remains an unsolved problem. We provide laboratory evidence that long-term weakening of the frictional strength of faults is caused by micro-fracturing at asperity contacts, which is a result of crack growth at subcritical stress levels. Our model suggests that long-term reductions of fault strength are related to chemical reactions that take place in the presence of water. For our measurements of friction on rupture surfaces in the presence of water, we increased temperatures to accelerate reaction processes so that they were observable at laboratory time-scales. In the presence of water, frictional strength decreased as temperature increased, whereas it changed little in the absence of water. The observed decreases in frictional strength were facilitated by chemical processes, rather than by physical processes governed by the effective pressure law. These observations suggest that chemical processes such as stress corrosion play an important role in long-term fault weakening. In addition to long-term monitoring of fault zones, we need to investigate long-term processes that cannot be observed during a human lifetime if we are to understand earthquake occurrences in the deep crust.

  18. Correlation of transverse momentum and multiplicity in a superposition model of nucleus-nucleus collisions

    SciTech Connect

    Mrowczynski, Stanislaw

    2006-04-15

    In p-p collisions the average transverse momentum is known to be correlated with the multiplicity of produced particles. The correlation is shown to survive in a superposition model of nucleus-nucleus collisions. When properly parametrized, the correlation strength appears to be independent of the collision centrality--it is the same in p-p and central A-A collisions. However, the correlation is strongly suppressed by the centrality fluctuations.

  19. Design study of a transverse-to-longitudinal emittance exchange proof-of-principle experiment

    SciTech Connect

    Sun, Y.-E.; Kim, K.-J.; Power, J. G.; Piot, P.; Rihaoui, M. M.; Northern Illinois Univ.; FNL

    2008-01-01

    Transverse-to-longitudinal emittance exchange can be achieved through certain arrangements of dipole magnets and a dipole mode rf cavity. Theory on such schemes has been developed in the past several years. In this paper we report our numerical simulations to optimize a low energy (E sime 15 MeV) proof-of-principle experiment planned at the Argonne Wakefield Accelerator (AWA). Parametric studies of the dipole magnets and cavity strengths, as well as initial beam parameters, are presented.

  20. Evolution of transverse modes in FELIX macropulses

    SciTech Connect

    Weits, H.H.; Lin, L.; Werkhoven, G.H.C. van

    1995-12-31

    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.

  1. Transverse dune trailing ridges and vegetation succession

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.; ‘Marisa' Martinez, M. L.

    2008-07-01

    We describe the evolution of, and vegetation succession on, a previously undescribed landform: transverse dune trailing ridges at El Farallón transgressive dunefield in the state of Veracruz, Mexico. Three-dimensional clinometer/compass and tape topographic surveys were conducted in conjunction with 1 m 2 contiguous percent cover and presence/absence vegetation survey transects at eight locations across two adjacent trailing ridges. At the study site, and elsewhere, the transverse dune trailing ridges are formed by vegetation colonization of the lateral margins of active transverse, barchanoidal transverse, and aklé or network dunes. For simplicity, all trailing ridges formed from these dune types are referred to as transverse dune trailing ridges. Because there are several transverse dunes in the dunefield, multiple trailing ridges can be formed at one time. Two adjacent trailing ridges were examined. The shortest length ridge was 70 m long, and evolving from a 2.5 m-high transverse dune, while the longer ridge was 140 m long, and evolving from an 8 m-high dune. Trailing ridge length is a proxy measure of ridge age, since the longer the ridge, the greater the length of time since initial formation. With increasing age or distance upwind, species diversity increased, as well as species horizontal extent and percent cover. In turn, the degree of bare sand decreased. Overall, the data indicate a successional trend in the vegetation presence and cover with increasing age upwind. Those species most tolerant to burial ( Croton and Palafoxia) begin the process of trailing ridge formation. Ipomoea and Canavalia are less tolerant to burial and also are typically the next colonizing species. Trachypogon does not tolerate sand burial or deposition very well and only appears after significant stabilization has taken place. The ridges display a moderately defined successional sequence in plant colonization and percentage cover with time (and upwind distance). They are

  2. Surface transverse waves: properties, devices, and analysis.

    PubMed

    Strashilov, Vesseline L; Yantchev, Ventsislav M

    2005-05-01

    Surface transverse waves represent a new generation of the surface acoustic wave (SAW) family that offers advantageous properties without further demand for new materials or improved design and technology. The most effective activity in the surface transverse wave (STW) area has been realized during the last decade with high-performance devices achieved and analytical methods developed. The present paper reviews the basic achievements in historical and factual order. A state-of-the-art introduction is combined with discussion on the development tendencies with specific emphasis on sensor technology.

  3. Rupture Limit of Thin Moving Films

    NASA Astrophysics Data System (ADS)

    Padrino, Juan C.; Joseph, Daniel D.; Kim, Hyungjun

    2010-11-01

    The rupture of a thin film in another fluid is studied including the effects of disjoining pressure. The study considers the linear stability of a moving viscous film in a motionless inviscid fluid and of a stagnant viscous film in a motionless viscous fluid. These are analyzed by means of the Navier--Stokes equations and the dissipation approximation based on potential flow. Results reveal that the dissipation method provides a good approximation for the case of a moving film, whereas its predictions are off the mark for the stagnant film case. The thickness of the gap at the trough of Kelvin-Helmholtz waves locates the formation of holes. The wavelength at final collapse is determined by the length of waves at the trough of the corrugated film. The disjoining pressure effects cause very fast break-up for very thin films. These effects influence the cutoff wavenumber. In the limit of small gaps on this corrugated film, the Reynolds and Weber numbers tend to zero with the gap size, the Ohnesorge number increases like the reciprocal of the square root and the Hamaker number like the reciprocal of the square of the gap. The motion of the film does not enter at the point of formation of holes. Moreover, for the most unstable wave, the ratio of the wavelength to film thickness is found to decrease with decreasing film thickness.

  4. Extensor tendon ruptures after total knee arthroplasty.

    PubMed

    Bonnin, M; Lustig, S; Huten, D

    2016-02-01

    Extensor tendon rupture is a rare but serious complication after total knee arthroplasty (TKA) that impairs active knee extension, thereby severely affecting knee function. Surgery is usually required. Surgical options range from simple suturing to allograft reconstruction of the entire extensor mechanism and include intermediate methods such as reconstruction using neighbouring tendons or muscles, synthetic ligament implantation, and partial allograft repair. Simple suturing carries a high failure rate and should therefore be routinely combined with tissue augmentation using a neighbouring tendon or a synthetic ligament. After allograft reconstruction, outcomes are variable and long-term complications common. Salvage procedures for managing the most severe cases after allograft failure involve reconstruction using gastrocnemius or vastus flaps. Regardless of the technique used, suturing must be performed under tension, with the knee fully extended, and rehabilitation must be conducted with great caution. Weaknesses of available case-series studies include small sample sizes, heterogeneity, and inadequate follow-up duration. All treatment options are associated with substantial failure rates. The patient should be informed of this fact and plans made for a salvage option. Here, the main techniques and their outcomes are discussed, and a therapeutic strategy is suggested.

  5. Spontaneous ureteral rupture diagnosis and treatment.

    PubMed

    Pampana, E; Altobelli, S; Morini, M; Ricci, A; D'Onofrio, S; Simonetti, G

    2013-01-01

    Rupture of the urinary collecting system associated with perinephric or retroperitoneal extravasation of the urine is an unusual condition and it is commonly associated with renal obstructing disease. Perforation could occur at any level from the calix to the bladder but it is usually seen at the fornices and upper ureter. It may lead to several serious consequences including urinoma, abscess formation, urosepsis, infection, and subsequent irreversible renal impairment. We report a case of a 69-year-old woman who presented at the emergency department of our institution with severe abdominal pain. Due to symptomatology worsening, complete laboratory evaluation was performed and the patient underwent abdominal contrast enhanced computed tomography (CT) evaluation which showed contrast agent extravasation outside the excretory system without any evidence of renal calculi at basal acquisition. It was decided to perform a double-J stent placement which was followed by complete healing of the ureter and its removal was performed 8 weeks later. Diagnosis and therapeutic approaches are discussed. PMID:24455381

  6. Patellar tendon rupture in a basketball player.

    PubMed

    Johnson, Sean D; Kulig, Kornelia

    2009-11-01

    The patient was a 21-year-old male who was referred to physical therapy with a 1-week history of right knee pain and stiffness following an injury of traumatic onset. While attempting to jump off of both legs to dunk a basketball during a game, the patient heard and felt a pop in his right knee that was associated with an immediate onset of pain and swelling. He was unable to bear weight following the injury and, therefore, immediately went to the emergency department, where radiographs were completed and interpreted as negative for a fracture. However, the patella for the right knee was superiorly displaced. The patient was issued crutches and referred to physical therapy. At the time of the initial physical therapy examination, the patient was still not able to bear full weight on the right lower extremity or actively fully extend his right knee. Due to concern over possible meniscal, medial collateral ligament, or patellar tendon involvement, the patient's physician was contacted and magnetic resonance imaging was ordered. Five days later, the patient presented with decreased knee effusion and the special tests for the medial collateral ligament and meniscus were negative. However, the patient was still not able to actively extend his knee, suggesting a possible rupture of the patellar tendon, which was later confirmed on magnetic resonance imaging. Surgical repair of the patellar tendon was performed 2 weeks later.

  7. Soft, Brown Rupture: Clinical Signs and Symptoms Associated with Ruptured PIP Breast Implants

    PubMed Central

    Duncan, Robert T.; Feig, Christine; Reintals, Michelle; Hill, Sarah

    2014-01-01

    Background: Preoperative signs and symptoms of patients with Poly Implant Prothese (PIP) implants could be predictive of device failure. Based on clinical observation and intraoperative findings 4 hypotheses were raised: (1) Preoperative clinical signs including acquired asymmetry, breast enlargement, fullness of the lower pole, decreased mound projection, and change in breast consistency could be indicative of implant rupture. (2) Device failure correlates with a low preoperative Baker grade of capsule. (3) Brown-stained implants are more prone to implant failure. (4) The brown gel could be indicative of iodine ingression through a substandard elastomer shell. Methods: Preoperative clinical signs were compared with intraoperative findings for 27 patients undergoing PIP implant explantation. Results: Acquired asymmetry (P = 0.0003), breast enlargement (P = 0.0002), fuller lower pole (P < 0.0001), and loss of lateral projection (P < 0.0001) were all significantly predictive of device failure. Capsule Baker grade was lower preoperatively for ruptured implants. The lack of palpable and visible preoperative capsular contracture could be secondary to the elastic nature of the capsular tissue found. Brown implants failed significantly more often than white implants. Analysis of brown gel revealed the presence of iodine, suggesting povidone iodine ingression at implantation. Conclusions: Preoperative signs can be predictive of PIP implant failure. Brown-stained implants are more prone to rupture. The presence of iodine in the gel suggests unacceptable permeability of the shell early in the implant’s life span. A noninvasive screening test to detect brown implants in situ could help identify implants at risk of failure in those who elect to keep their implants. PMID:25506532

  8. Creep Deformation and Rupture Behavior of Single- and Dual-Pass 316LN Stainless-Steel-Activated TIG Weld Joints

    NASA Astrophysics Data System (ADS)

    Vijayanand, V. D.; Vasudevan, M.; Ganesan, V.; Parameswaran, P.; Laha, K.; Bhaduri, A. K.

    2016-06-01

    Creep deformation and rupture behavior of single-pass and dual-pass 316LN stainless steel (SS) weld joints fabricated by an autogenous activated tungsten inert gas welding process have been assessed by performing metallography, hardness, and conventional and impression creep tests. The fusion zone of the single-pass joint consisted of columnar zones adjacent to base metals with a central equiaxed zone, which have been modified extensively by the thermal cycle of the second pass in the dual-pass joint. The equiaxed zone in the single-pass joint, as well as in the second pass of the dual-pass joint, displayed the lowest hardness in the joints. In the dual-pass joint, the equiaxed zone of the first pass had hardness comparable to the columnar zone. The hardness variations in the joints influenced the creep deformation. The equiaxed and columnar zone in the first pass of the dual-pass joint was more creep resistant than that of the second pass. Both joints possessed lower creep rupture life than the base metal. However, the creep rupture life of the dual-pass joint was about twofolds more than that of the single-pass joint. Creep failure in the single-pass joint occurred in the central equiaxed fusion zone, whereas creep cavitation that originated in the second pass was blocked at the weld pass interface. The additional interface and strength variation between two passes in the dual-pass joint provides more restraint to creep deformation and crack propagation in the fusion zone, resulting in an increase in the creep rupture life of the dual-pass joint over the single-pass joint. Furthermore, the differences in content, morphology, and distribution of delta ferrite in the fusion zone of the joints favors more creep cavitation resistance in the dual-pass joint over the single-pass joint with the enhancement of creep rupture life.

  9. Irradiation creep and creep rupture of titanium-modified austenitic stainless steels and their dependence on cold work level

    SciTech Connect

    Garner, F.A.; Hamilton, M.L.; Eiholzer, C.R.; Toloczko, M.B.; Kumar, A.S.

    1991-11-01

    A titanium-modified austenitic type stainless steel was tested at three cold work levels to determine its creep and creep rupture properties under both thermal aging and neutron irradiation conditions. Both the thermal and irradiation creep behavior exhibit a complex non-monotonic relationship with cold work level that reflects the competition between a number of stress-sensitive and temperature-dependent microstructural processes. Increasing the degree of cold work to 30% from the conventional 20% level was detrimental to its performance, especially for applications above 550{degrees}c. The 20% cold work level is preferable to the 10% level, in terms of both in-reactor creep rupture response and initial strength.

  10. Staged Management of a Ruptured Internal Mammary Artery Aneurysm

    PubMed Central

    Kwon, O Young; Kim, Gun Jik; Oh, Tak Hyuk; Lee, Young Ok; Lee, Sang Cjeol; Cho, Jun Yong

    2016-01-01

    The rupture of an internal mammary artery (IMA) aneurysm in a patient with type 1 neurofibromatosis (NF-1) is a rare but life-threatening complication requiring emergency management. A 50-year-old man with NF-1 was transferred to the emergency department of Kyungpook National University Hospital, where an IMA aneurysmal rupture and hemothorax were diagnosed and drained. The IMA aneurysmal rupture and hemothorax were successfully repaired by staged management combining endovascular treatment and subsequent video-assisted thoracoscopic surgery (VATS). The patient required cardiopulmonary cerebral resuscitation, the staged management of coil embolization, and a subsequent VATS procedure. This staged approach may be an effective therapeutic strategy in cases of IMA aneurysmal rupture. PMID:27066438

  11. Endobronchial Cartilage Rupture: A Rare Cause of Lobar Collapse

    PubMed Central

    Siddiqui, Nauman; Javaid, Toseef

    2016-01-01

    Endobronchial cartilage rupture is a rare clinical condition, which can present in patients with severe emphysema with sudden onset shortness of breath. We present a case of a 62-year-old male who presented to our emergency department with sudden onset shortness of breath. Chest X-ray showed lung hyperinflation and a right lung field vague small density. Chest Computed Tomography confirmed the presence of right middle lobe collapse. Bronchoscopy revealed partial right middle lobe atelectasis and an endobronchial cartilage rupture. Endobronchial cartilage rupture is a rare condition that can present as sudden onset shortness of breath due to lobar collapse in patients with emphysema and can be triggered by cough. Bronchoscopic findings include finding a collapsed lung lobe and a visible ruptured endobronchial cartilage. A high index of suspicion, chest imaging, and early bronchoscopy can aid in the diagnosis and help prevent complications. PMID:27525149

  12. Automatic rupture of unused intraport catheter. Case report.

    PubMed

    Pappas, Paris; Dalianis, Nikolaos; Filippou, Dimitrios K; Condiis, Nicolas; Rizos, Spiros; Skandalakis, Panagiotis

    2007-01-01

    Totally Implantable Central Venous Access Devices (Intraports) are commonly used in cancer patients to administer chemotherapy or parenteral nutrition. These devices are placed by Seldinger technique. We report an unusual case of intraport catheter rupture before the use of the device. The ruptured part of the catheter migrated into the left pulmonary vein via right ventricle. The ruptured part was removed by means of interventional radiology before causing any problems to the patient. All the reported ruptures of port catheters refer to port devices that had been used to administer chemotherapy, fluids, or parenteral nutrition. The unique feature of this case is that the catheter had not been used at all. It is of great interest also the removal of the broken part from the pulmonary vein.

  13. Delayed aortic rupture resulting from postoperative superficial sternal wound infection

    PubMed Central

    Kim, Su Wan; Chang, Jee Won

    2016-01-01

    While deep sternal wound infection (DSWI) after cardiac surgery is a significant contributor to patient morbidity and mortality, superficial sternal wound infection (SSWI) mostly has a benign course. We report a mortality case of aortic rupture resulting from SSWI after cardiac surgery. A 50-year-old male underwent an aortic valve replacement (AVR). Three months after the valve operation, he presented with severe dyspnea, which had never before been observed, and chest computed tomography revealed an ascending aortic rupture with large hematoma compressing the main pulmonary artery. We performed an emergent operation for aortic rupture that possibly originated from the SSWI. Postoperatively, the patient died of hypovolemic shock due to recurrent aortic rupture despite efforts to resuscitate him. PMID:27499988

  14. Cocaine Use and Splenic Rupture: A Rare Yet Serious Association

    PubMed Central

    Karthik, Nishrutha; Gnanapandithan, Karthik

    2016-01-01

    Cocaine abuse is frequent in patients visiting the emergency department. The knowledge of the cardiovascular complications of cocaine is excellent among physicians. However the awareness regarding its abdominal complications, the most important of which include gastroduodenal perforation, bowel ischemia and splenic rupture is less adequate. We report a 58-year-old with cocaine use who presents with upper abdominal pain and a rapidly worsening clinical status. He was found to have atraumatic splenic rupture causing a hemoperitoneum that was managed by intervention radiology guided splenic artery embolization. Splenic hemorrhage and rupture need timely recognition, as they are difficult to diagnose clinically and can be potentially fatal. In the encounter of patients with cocaine use who present with chest or upper abdominal pain, clinicians should consider imaging to look for splenic rupture as it is often masked or overlooked due to the complicated clinical picture. PMID:27777711

  15. Ruptured chordae tendineae in acromegaly. An autopsy case.

    PubMed

    Kaku, T; Nakashima, Y; Ichiyasu, H; Soejima, M; Baba, K; Kuroiwa, A

    1991-07-01

    A 57-year-old woman with acromegaly associated with mitral chordal rupture is reported. She was noted to have abnormal development in the size of her hands and feet in childhood. She occasionally suffered from shortness of breath on exertion and nocturnal dyspnea for several years, and was diagnosed and treated as having congestive heart failure due to valvular heart disease. On admission to our hospital, chordal rupture was suspected on the basis of M-mode and two-dimensional echocardiography. Seven years after discharge, she died of congestive heart failure. On autopsy, the heart weight and ventricular wall thickness were increased. Rupture of the posterior chordae was confirmed, but evidence of an old myocardial infarction was not found. There was severe interstitial fibrosis in the left ventricular wall. A possible etiology of the chordal rupture in this case was thought to be the excessive stretching caused by the disproportional visceromegaly of the heart.

  16. Splenic rupture as a presenting feature of endocarditis.

    PubMed

    Winearls, James Roger; McGloughlin, Steven; Fraser, John F

    2009-04-01

    We describe the first case of infective endocarditis presenting with spontaneous splenic rupture. Our patient, a known intravenous drug user presented with hypovolaemic shock secondary to splenic rupture. The patient was resuscitated and underwent an emergency splenectomy. Subsequent clinical examination revealed a systolic murmur and a diagnosis of mitral valve infective endocarditis was made after echocardiography. Splenic tissue, blood cultures and mitral valve tissue all cultured Enterococcus faecalis. The patient had a successful mitral valve replacement and was discharged home after 44 days. To our knowledge this is the first reported case of enterococcal endocarditis presenting with splenic rupture. This case highlights the need to consider endocarditis in spontaneous splenic rupture particularly in those patients in a high risk group, such as IV drug users, especially if they lack a clear history of trauma. PMID:19217796

  17. Endobronchial Cartilage Rupture: A Rare Cause of Lobar Collapse.

    PubMed

    Dasa, Osama; Siddiqui, Nauman; Ruzieh, Mohammed; Javaid, Toseef

    2016-01-01

    Endobronchial cartilage rupture is a rare clinical condition, which can present in patients with severe emphysema with sudden onset shortness of breath. We present a case of a 62-year-old male who presented to our emergency department with sudden onset shortness of breath. Chest X-ray showed lung hyperinflation and a right lung field vague small density. Chest Computed Tomography confirmed the presence of right middle lobe collapse. Bronchoscopy revealed partial right middle lobe atelectasis and an endobronchial cartilage rupture. Endobronchial cartilage rupture is a rare condition that can present as sudden onset shortness of breath due to lobar collapse in patients with emphysema and can be triggered by cough. Bronchoscopic findings include finding a collapsed lung lobe and a visible ruptured endobronchial cartilage. A high index of suspicion, chest imaging, and early bronchoscopy can aid in the diagnosis and help prevent complications. PMID:27525149

  18. Acute Bilateral Traumatic Achilles Tendon Rupture – A Rare Presentation

    PubMed Central

    Jhaveri, Maulik; Golwala, Paresh; Merh, Aditya; Patel, Amit

    2016-01-01

    The Achilles tendon is the strongest tendon in the body, which is commonly ruptured in male athletes. Bilateral rupture of the Achilles tendon is a rare condition with very few reported cases in the literature. It poses a challenge in management, and hence, we report a case with traumatic bilateral Achilles tendon rupture in a young male patient and its management. One side was treated conservatively as the rupture was partial and the other side, which had a complete tear, was operated. At nine months follow-up, the patient has had a satisfactory result and is now bearing full weight without any problems. We suggest this method of treatment to be worthwhile for this unusual entity. PMID:27588227

  19. Etiology and pathophysiology of tendon ruptures in sports.

    PubMed

    Kannus, P; Natri, A

    1997-04-01

    Of all spontaneous tendon ruptures, complete Achilles tendon tears are most closely associated with sports activities (1-3). Schönbauer (3) reported that 75% of all ruptures of the Achilles tendon are related to sports. In Plecko & Passl (2) the number was 60%. In our material of 430 cases, the number of sports-related Achilles ruptures was very similar (62%), while only 2% of ruptures of other tendons were sports-related (P < 0.001) (1). Also, the majority of Achilles reruptures occurred in sports. The ruptures occurred most often in soccer (34%), track and field (16%) and basketball (14%). The distribution of Achilles ruptures according to different sports varies considerably from country to country, according to the national sport traditions. For example, in northern and middle Europe, soccer, tennis, track and field, indoor ball games, downhill skiing, and gymnastics are the most common; and in North America, football, basketball, baseball, tennis and downhill skiing dominate the statistics (1, 2, 4). In sports, some Achilles ruptures are not spontaneous or degeneration-induced but may occur as a consequence of the remarkably high forces that are involved in the performance (2). Ruptures in the high jump or triple jump are good examples. In such cases, failure in the neuromuscular protective mechanisms due to fatigue or disturbed co-ordination can frequently be found. The spontaneous complete rupture of the supraspinatus tendon of the rotator cuff does not occur very frequently in sports. Those sports that include high-energy throwing movements, such as American and Finnish baseball, American football, rugby and discuss and javelin throwing, may, however, produce this injury. Partial tears and inflammations of the rotator cuff complex are much more frequent in throwing sports. The complete rupture of the proximal long head of the biceps brachii tendon is rare among competitive and recreational athletes. In our material, under 2% of these ruptures were

  20. Strength Modeling Report

    NASA Technical Reports Server (NTRS)

    Badler, N. I.; Lee, P.; Wong, S.

    1985-01-01

    Strength modeling is a complex and multi-dimensional issue. There are numerous parameters to the problem of characterizing human strength, most notably: (1) position and orientation of body joints; (2) isometric versus dynamic strength; (3) effector force versus joint torque; (4) instantaneous versus steady force; (5) active force versus reactive force; (6) presence or absence of gravity; (7) body somatotype and composition; (8) body (segment) masses; (9) muscle group envolvement; (10) muscle size; (11) fatigue; and (12) practice (training) or familiarity. In surveying the available literature on strength measurement and modeling an attempt was made to examine as many of these parameters as possible. The conclusions reached at this point toward the feasibility of implementing computationally reasonable human strength models. The assessment of accuracy of any model against a specific individual, however, will probably not be possible on any realistic scale. Taken statistically, strength modeling may be an effective tool for general questions of task feasibility and strength requirements.

  1. Retrograde approach for closure of ruptured sinus of Valsalva.

    PubMed

    Jayaranganath, M; Subramanian, Anand; Manjunath, Cholenahally Nanjappa

    2010-07-01

    Though ruptured sinuses of Valsalva have been traditionally managed surgically, they are amenable to transcatheter closure. Various devices have been used for closure of these defects. We describe a novel technique of closure of a ruptured right sinus of Valsalva into the right ventricular outflow tract. A muscular ventricular septal defect occluder was deployed retrogradely, without resorting to the usual antegrade technique involving formation of an arteriovenous loop. PMID:20603510

  2. Paraplegia due to Spinal Epidermoid Cyst Rupture at Asthma Attack

    PubMed Central

    Kim, Kweon Young; Kang, Jung Hun; Choi, Dae Woo; Lee, Min Hong

    2013-01-01

    Spinal epidermoid cyst is less than 1% of the entire spinal cord tumor and a rare tumor. It is a slowly proliferating benign tumor and can be a result of either congenital or acquired factors. In particular, reports of acute paraplegia due to spinal epidermoid cyst rupture are very rare. Since authors experienced paraplegia resulting from congenital spinal epidermoid cyst rupture during an asthma attack, it is reported with a review of literature. PMID:23705125

  3. Multiple branching rupture of the 2009 Tonga-Samoa earthquake

    NASA Astrophysics Data System (ADS)

    Fan, Wenyuan; Shearer, Peter M.; Ji, Chen; Bassett, Dan

    2016-08-01

    Several source models have been proposed to explain the enigmatic 2009 Tonga-Samoa earthquake. The long-period data require a composite source model and can be fit with a normal-faulting subevent followed by one or more reverse-faulting subevents. The short-period data, in contrast, indicate a more compact rupture pattern around the epicenter. The lack of a unified source model reflects the complexity of the event. We analyze the spatiotemporal evolution of this earthquake with P wave back-projection from globally distributed stations in different frequency bands (low frequency: 0.05-0.2 Hz, high frequency: 0.2-2 Hz) and a multiple moment tensor inversion. The rupture propagation revealed by back-projection exhibits frequency-dependent behavior, with two branches of high-frequency-enriched bilateral rupture around the epicenter and a high-frequency-deficient rupture branch at the subduction interface. A composite source model with one Mw 8.0 normal-faulting earthquake east of the trench axis (seaward) followed by one Mw 8.1 reverse-faulting earthquake along the subduction interface west of the trench axis (landward) can explain the very long period data (200˜500 s). Combined with high-resolution swath bathymetry data, the back-projection images show that the azimuth of rupture branches east of the trench axis were controlled by the geometry of bending-related faults on the Pacific plate and that the rupture branch west of the trench axis may correlate with the along-strike fore-arc segmentation. The rupture along the subduction interface was triggered by the seaward rupture and a partially subducted normal fault may have played a key role in facilitating the triggering. The apparent normal-reverse faulting interactions pose a higher seismic risk to this region than their individual strands at the northernmost corner of the Tonga subduction zone.

  4. Cohesive zone length of metagabbro at supershear rupture velocity

    NASA Astrophysics Data System (ADS)

    Fukuyama, Eiichi; Xu, Shiqing; Yamashita, Futoshi; Mizoguchi, Kazuo

    2016-06-01

    We investigated the shear strain field ahead of a supershear rupture. The strain array data along the sliding fault surfaces were obtained during the large-scale biaxial friction experiments at the National Research Institute for Earth Science and Disaster Resilience. These friction experiments were done using a pair of meter-scale metagabbro rock specimens whose simulated fault area was 1.5 m × 0.1 m. A 2.6-MPa normal stress was applied with loading velocity of 0.1 mm/s. Near-fault strain was measured by 32 two-component semiconductor strain gauges installed at an interval of 50 mm and 10 mm off the fault and recorded at an interval of 1 MHz. Many stick-slip events were observed in the experiments. We chose ten unilateral rupture events that propagated with supershear rupture velocity without preceding foreshocks. Focusing on the rupture front, stress concentration was observed and sharp stress drop occurred immediately inside the ruptured area. The temporal variation of strain array data is converted to the spatial variation of strain assuming a constant rupture velocity. We picked up the peak strain and zero-crossing strain locations to measure the cohesive zone length. By compiling the stick-slip event data, the cohesive zone length is about 50 mm although it scattered among the events. We could not see any systematic variation at the location but some dependence on the rupture velocity. The cohesive zone length decreases as the rupture velocity increases, especially larger than √{2} times the shear wave velocity. This feature is consistent with the theoretical prediction.

  5. Atraumatic splenic rupture after coagulopathy owing to a snakebite.

    PubMed

    Kang, Changwoo; Kim, Dong Hoon; Kim, Seong Chun; Kim, Dong Seob; Jeong, Chi-Young

    2014-09-01

    Among the many complications that may follow envenomation by some species of venomous snakes, coagulopathy is common and well known. However, hemoperitoneum induced by coagulopathy after a snakebite is rare. Atraumatic spontaneous splenic rupture is also an uncommon and life-threatening condition. Here, we report a case of presumptive envenomation by Gloydius spp. that resulted in atraumatic splenic rupture as a probable manifestation of coagulopathy, which has not been previously reported. PMID:24882658

  6. Softball injury causing haemoperitoneum due to ruptured Meckel's mesodiverticular band.

    PubMed

    Woodfield, Julie; Barnett, Mark; Shapkov, Peter

    2011-10-14

    A 16-year-old male sustained an intra-abdominal haemorrhage after diving for last base during a softball game. At laparotomy a ruptured patent mesodiverticular band supplying a large Meckel's diverticulum was found. Traumatic rupture of a mesodiverticular band leading to massive intra-abdominal haemorrhage is a rare event, and has never been reported as a single injury or in the context of a sport's injury.

  7. First report of splenic rupture following deep enteroscopy

    PubMed Central

    Girelli, Carlo Maria; Pometta, Roberta; Facciotto, Corinna; Mella, Roberto; Bernasconi, Giordano

    2016-01-01

    Splenic rupture is a rare complication of diagnostic and therapeutic gastrointestinal endoscopy procedures. Herein, we report for the first time a case of splenic rupture following therapeutic retrograde double-balloon enteroscopy, which occurred in an 85-year-old man who was treated for recurrent mid-intestinal bleeding that resulted from ileal angioectasia. This patient promptly underwent an operation and eventually recovered. PMID:27170840

  8. Dose response of selected solid state detectors in applied homogeneous transverse and longitudinal magnetic fields

    SciTech Connect

    Reynolds, M.; Fallone, B. G.; Rathee, S.

    2014-09-15

    Purpose: MR-Linac devices under development worldwide will require standard calibration, commissioning, and quality assurance. Solid state radiation detectors are often used for dose profiles and percent depth dose measurements. The dose response of selected solid state detectors is therefore evaluated in varying transverse and longitudinal magnetic fields for this purpose. Methods: The Monte Carlo code PENELOPE was used to model irradiation of a PTW 60003 diamond detector and IBA PFD diode detector in the presence of a magnetic field. The field itself was varied in strength, and oriented both transversely and longitudinally with respect to the incident photon beam. The long axis of the detectors was oriented either parallel or perpendicular to the photon beam. The dose to the active volume of each detector in air was scored, and its ratio to dose with zero magnetic field strength was determined as the “dose response” in magnetic field. Measurements at low fields for both detectors in transverse magnetic fields were taken to evaluate the accuracy of the simulations. Additional simulations were performed in a water phantom to obtain few representative points for beam profile and percent depth dose measurements. Results: Simulations show significant dose response as a function of magnetic field in transverse field geometries. This response can be near 20% at 1.5 T, and it is highly dependent on the detectors’ relative orientation to the magnetic field, the energy of the photon beam, and detector composition. Measurements at low transverse magnetic fields verify the simulations for both detectors in their relative orientations to radiation beam. Longitudinal magnetic fields, in contrast, show little dose response, rising slowly with magnetic field, and reaching 0.5%–1% at 1.5 T regardless of detector orientation. Water tank and in air simulation results were the same within simulation uncertainty where lateral electronic equilibrium is present and expectedly

  9. 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

    Hartzell, Stephen; Mendoza, Carlos; Ramírez-Guzmán, Leonardo; Zeng, Yuesha; Mooney, Walter

    2013-01-01

    An extensive data set of teleseismic and strong-motion waveforms and geodetic offsets is used to study the rupture history of the 2008 Wenchuan, China, 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°–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’s 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 1.0 × 1021 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.

  10. Alumina strength degradation in the elastic regime

    SciTech Connect

    Furnish, M.D.; Chhabildas, L.C.

    1997-08-01

    Measurements of Kanel et. al. [1991] have suggested that deviatoric stresses in glasses shocked to nearly the Hugoniot Elastic limit (HEL) relax over a time span of microseconds after initial loading. Failure (damage) waves have been inferred on the basis of these measurements using time-resolved manganin normal and transverse stress gauges. Additional experiments on glass by other researchers, using time-resolved gauges, high-speed photography and spall strength determinations have also lead to the same conclusions. In the present study the authors have conducted transmitted-wave experiments on high-quality Coors AD995 alumina shocked to roughly 5 and 7 GPa (just below or at the HEL). The material is subsequently reshocked to just above its elastic limit. Results of these experiments do show some evidence of strength degradation in the elastic regime.

  11. The temporal distribution of seismic radiation during deep earthquake rupture

    USGS Publications Warehouse

    Houston, H.; Vidale, J.E.

    1994-01-01

    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.

  12. Limitations of rupture forecasting exposed by instantaneously triggered earthquake doublet

    NASA Astrophysics Data System (ADS)

    Nissen, E.; Elliott, J. R.; Sloan, R. A.; Craig, T. J.; Funning, G. J.; Hutko, A.; Parsons, B. E.; Wright, T. J.

    2016-04-01

    Earthquake hazard assessments and rupture forecasts are based on the potential length of seismic rupture and whether or not slip is arrested at fault segment boundaries. Such forecasts do not generally consider that one earthquake can trigger a second large event, near-instantaneously, at distances greater than a few kilometres. Here we present a geodetic and seismological analysis of a magnitude 7.1 intracontinental earthquake that occurred in Pakistan in 1997. We find that the earthquake, rather than a single event as hitherto assumed, was in fact an earthquake doublet: initial rupture on a shallow, blind reverse fault was followed just 19 s later by a second rupture on a separate reverse fault 50 km away. Slip on the second fault increased the total seismic moment by half, and doubled both the combined event duration and the area of maximum ground shaking. We infer that static Coulomb stresses at the initiation location of the second earthquake were probably reduced as a result of the first. Instead, we suggest that a dynamic triggering mechanism is likely, although the responsible seismic wave phase is unclear. Our results expose a flaw in earthquake rupture forecasts that disregard cascading, multiple-fault ruptures of this type.

  13. Bilateral renal rupture in a patient on hemodialysis.

    PubMed

    Carlson, Chris C; Holsten, Steve J; Grandas, Oscar H

    2003-06-01

    This is a case presentation and discussion of a dialysis patient who presented to the surgical service with abdominal pain, hypotension, and tachycardia and in extremis who was found to have a contained retroperitoneal hematoma after rupture of his left kidney. Six months after an uneventful nephrectomy and postoperative recovery he again presented with hypotension and anemia and was found to have a contralateral retroperitoneal hematoma consistent with renal hemorrhage. After unsuccessful angioembolization, the patient underwent a right nephrectomy and recovered without sequelae. Bilateral spontaneous renal rupture is a rare event documented by only a few anecdotal reports in the literature and usually associated with acquired cystic kidney disease. Rupture of renal cysts is relatively common in renal cystic disease but usually presents as asymptomatic hematuria or flank pain. Trauma is the most common cause of renal rupture, but other causes of spontaneous renal rupture are rare and include polyarteritis nodosa and urothelial carcinoma. The diagnosis of acute abdominal pain in the dialysis patient is a challenging differential. While a rare complication the diagnosis of spontaneous renal rupture should not be excluded in a patient presenting with abdominal pain, hypotension, and anemia.

  14. Ground-motion signature of dynamic ruptures on rough faults

    NASA Astrophysics Data System (ADS)

    Mai, P. Martin; Galis, Martin; Thingbaijam, Kiran K. S.; Vyas, Jagdish C.

    2016-04-01

    Natural earthquakes occur on faults characterized by large-scale segmentation and small-scale roughness. This multi-scale geometrical complexity controls the dynamic rupture process, and hence strongly affects the radiated seismic waves and near-field shaking. For a fault system with given segmentation, the question arises what are the conditions for producing large-magnitude multi-segment ruptures, as opposed to smaller single-segment events. Similarly, for variable degrees of roughness, ruptures may be arrested prematurely or may break the entire fault. In addition, fault roughness induces rupture incoherence that determines the level of high-frequency radiation. Using HPC-enabled dynamic-rupture simulations, we generate physically self-consistent rough-fault earthquake scenarios (M~6.8) and their associated near-source seismic radiation. Because these computations are too expensive to be conducted routinely for simulation-based seismic hazard assessment, we thrive to develop an effective pseudo-dynamic source characterization that produces (almost) the same ground-motion characteristics. Therefore, we examine how variable degrees of fault roughness affect rupture properties and the seismic wavefield, and develop a planar-fault kinematic source representation that emulates the observed dynamic behaviour. We propose an effective workflow for improved pseudo-dynamic source modelling that incorporates rough-fault effects and its associated high-frequency radiation in broadband ground-motion computation for simulation-based seismic hazard assessment.

  15. Dynamic rupture modeling with laboratory-derived constitutive relations

    USGS Publications Warehouse

    Okubo, P.G.

    1989-01-01

    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

  16. Transverse instability digital damper for the Recycler

    SciTech Connect

    Balbekov, V.; /Fermilab

    2006-02-01

    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.

  17. Variation of transverse momentum in hadronic collisions

    NASA Technical Reports Server (NTRS)

    Saint Amand, J.; Uritam, R. A.

    1975-01-01

    The paper presents a detailed parameterization of the transverse momentum in hadronic collisions on multiplicity and on beam momentum. Hadronic collisions are considered at energies below the ultra-high energy domain, on the basis of an uncertainty relation and a naive eikonal model with an impact-parameter-dependent multiplicity.

  18. Transversal filter for parabolic phase equalization

    NASA Technical Reports Server (NTRS)

    Kelly, Larry R. (Inventor); Waugh, Geoffrey S. (Inventor)

    1993-01-01

    An equalizer (10) for removing parabolic phase distortion from an analog signal (3), utilizing a pair of series connected transversal filters. The parabolic phase distortion is cancelled by generating an inverse parabolic approximation using a sinusoidal phase control filter (18). The signal (3) is then passed through an amplitude control filter (21) to remove magnitude ripple components.

  19. Transverse ligament of the knee in humans.

    PubMed

    Ratajczak, Wojciech; Jakubowicz, Marian; Pytel, Andrzej

    2003-01-01

    The purpose of this study was to trace the histological structure of the transverse ligament of the knee and its relation to the inferior lateral genicular artery. Investigations were carried out on 20 lower limbs (10 males, and 10 females) from the Department of Anatomy. It was found that close to the attachment of the transverse ligament to the menisci, bundles of fibres pass in vertical, oblique and horizontal directions, occupying a wide area on the anterior margin of the menisci. These fibres intermingle with bundles of the fibrocartilage of the menisci. In the area of the lateral attachment the inferior lateral genicular artery passes anteriorly to the transverse ligament, giving off numerous branches to the ligament. The medial part of the transverse ligament presents a thick rounded structure, surrounded by loose connective tissue. The fibres are arranged irregularly in bundles running horizontally on a tortuous course and with single spindle-like cells with darkly stained nuclei. The cells are not found at the ends of the ligament. Numerous blood vessels are observed between the bundles of fibres and on the periphery of the ligament.

  20. Transverse stability in a Stark decelerator

    SciTech Connect

    Meerakker, Sebastiaan Y. T. van de; Bethlem, Hendrick L.; Vanhaecke, Nicolas; Meijer, Gerard

    2006-02-15

    The concept of phase stability in a Stark decelerator ensures that polar molecules can be accelerated, guided, or decelerated without loss; molecules within a certain position and velocity interval are kept together throughout the deceleration process. In this paper the influence of the transverse motion on phase stability in a Stark decelerator is investigated. For typical deceleration experiments--i.e., for high values of the phase angle {phi}{sub 0}--the transverse motion considerably enhances the region in phase space for which phase stable deceleration occurs. For low values of {phi}{sub 0}, however, the transverse motion reduces the acceptance of a Stark decelerator and unstable regions in phase space appear. These effects are quantitatively explained in terms of a coupling between the longitudinal and transverse motion. The predicted longitudinal acceptance of a Stark decelerator is verified by measurements on a beam of OH (X {sup 2}{pi}{sub 3/2},J=3/2) radicals passing through a Stark decelerator.