Sample records for thermal fractures

  1. Natural thermal convection in fractured porous media (United States)

    Adler, P. M.; Mezon, C.; Mourzenko, V.; Thovert, J. F.; Antoine, R.; Finizola, A.


    In the crust, fractures/faults can provide preferential pathways for fluid flow or act as barriers preventing the flow across these structures. In hydrothermal systems (usually found in fractured rock masses), these discontinuities may play a critical role at various scales, controlling fluid flows and heat transfer. The thermal convection is numerically computed in 3D fluid satured fractured porous media. Fractures are inserted as discrete objects, randomly distributed over a damaged volume, which is a fraction of the total volume. The fluid is assumed to satisfy Darcy's law in the fractures and in the porous medium with exchanges between them. All simulations were made for Rayleigh numbers (Ra) fracture aperture (or fracture transmissivity), fracture density and fracture length is studied. Moreover, these models are compared to porous media with the same macroscopic permeability. Preliminary results show that the non-uniqueness associated with initial conditions which makes possible either 2D or 3D convection in porous media (Schubert & Straus 1979) is no longer true for fractured porous media (at least for 50fracture density and fracture aperture on the Nusselt number (Nu) is highly Ra dependent. The effect of the damaged zone on Nu is roughly proportional to its size. All these models also allows us to determine for which range of fracture density the fractured porous medium is in good agreement with an unfractured porous medium of the same bulk permeability.

  2. Thermal stress fracture of ceramic coatings (United States)

    Andersson, C. A.


    Thermal stress failures of ceramic coatings are discussed in terms of fracture mechanics concepts. The effects of transient and residual stresses on single and multiple cycle failure mechanisms are considered. A specific example of a zirconia thermal barrier coating is presented and its endurance calculated using the proposed relationships.

  3. Thermal stress fracturing of magma simulant materials

    Energy Technology Data Exchange (ETDEWEB)

    Wemple, R.P.; Longcope, D.B.


    Direct contact heat exchanger concepts for the extraction of energy from magma chambers are being studied as part of the DOE-funded Magma Energy Research Program at Sandia National Laboratories. These concepts require the solidification of molten material by a coolant circulated through a borehole drilled into the magma and subsequent fracture of the solid either as a natural consequence of thermal stress or by deliberate design (intentional flaws, high pressure, etc.). This report summarizes the results of several thermal stress fracturing experiments performed in the laboratory and compares the results with an analysis developed for use as a predictive tool. Information gained from this test series has been the basis for additional work now under way to simulate magma melt solidification processes.

  4. Fracture driven by a Thermal Gradient

    CERN Document Server

    Pla, O


    Motivated by recent experiments by Yuse and Sano (Nature, 362, 329 (1993)), we propose a discrete model of linear springs for studying fracture in thin and elastically isotropic brittle films. The method enables us to draw a map of the stresses in the material. Cracks generated by the model, imposing a moving thermal gradient in the material, can branch or wiggle depending on the driving parameters. The results may be used to compare with other recent theoretical work, or to design future experiments.

  5. Thermal convection in three-dimensional fractured porous media (United States)

    Mezon, C.; Mourzenko, V. V.; Thovert, J.-F.; Antoine, R.; Fontaine, F.; Finizola, A.; Adler, P. M.


    Thermal convection is numerically computed in three-dimensional (3D) fluid saturated isotropically fractured porous media. Fractures are randomly inserted as two-dimensional (2D) convex polygons. Flow is governed by Darcy's 2D and 3D laws in the fractures and in the porous medium, respectively; exchanges take place between these two structures. Results for unfractured porous media are in agreement with known theoretical predictions. The influence of parameters such as the fracture aperture (or fracture transmissivity) and the fracture density on the heat released by the whole system is studied for Rayleigh numbers up to 150 in cubic boxes with closed-top conditions. Then, fractured media are compared to homogeneous porous media with the same macroscopic properties. Three major results could be derived from this study. The behavior of the system, in terms of heat release, is determined as a function of fracture density and fracture transmissivity. First, the increase in the output flux with fracture density is linear over the range of fracture density tested. Second, the increase in output flux as a function of fracture transmissivity shows the importance of percolation. Third, results show that the effective approach is not always valid, and that the mismatch between the full calculations and the effective medium approach depends on the fracture density in a crucial way.



    Stefan Karlsson


    Thermal strengthening of glass is common for many different purposes including architecture, automotive, glasses for solar energy, tableware and occasionally also containers. It is an easy and relatively cheap method to make glasses stronger, however, with an Achilles heel that it can spontaneously fracture without the slightest applied external force. Though, fracture due to applied external force is the most common case, spontaneous fracture is rare. The current paper reviews the literature...

  7. Numerical simulation of thermal fracture in functionally graded ...

    Indian Academy of Sciences (India)

    In the present work, element-free Galerkin method (EFGM) has been extended and implemented to simulate thermal fracture in functionally graded materials. The thermo-elastic fracture problem is decoupled into two separate parts. Initially, the temperature distribution over the domain is obtained by solving the heat transfer ...

  8. Thermal stresses, differential subsidence, and flexure at oceanic fracture zones (United States)

    Wessel, Pal; Haxby, William F.


    Geosat geoid undulations over four Pacific fracture zones have been analyzed. After correcting for the isostatic thermal edge effect, the amplitudes of the residuals are shown to be proportional to the age offset. The shape of the residuals seems to broaden with increasing age. Both geoid anomalies and available ship bathymetry data suggest that slip must sometimes occur on the main fracture zone or secondary faults. Existing models for flexure at fracture zones cannot explain the observed anomalies. A combination model accounting for slip and including flexure from thermal stresses and differential subsidence is presented. This model accounts for lateral variations in flexural rigidity from brittle and ductile yielding due to both thermal and flexural stresses and explains both the amplitudes and the shape of the anomalies along each fracture zone. The best fitting models have mechanical plate thicknesses that are described by the depth to the 600-700 C isotherms.

  9. The equivalent thermal properties of a single fracture (United States)

    Adler, P. M.; Sangare, D.; Thovert, J. F.


    The major objective of this communication is to determine in a steady state the equivalent thermal resistance of a fracture embedded in a conducting medium when a constant temperature gradient is imposed far away from the fracture. This gradient is either perpendicular or parallel to the fracture plane. In the first situation, the fracture corresponds roughly to a layer of conductivity lambdaf in between two blocks with the same conductivity lambda; it is equivalent to an additional resistance (which can be negative) in series with the two solid blocks. In the second situation, the fracture corresponds to an element in parallel with the two solid blocks; therefore, it is more straightforward to study the tangential conductivity rather than the tangential resistance. These two quantities are systematically addressed. Of course, the thermal resistance is the inverse of the thermal conductivity and these quantities can be easily derived one from another. It is important to notice that this work is not limited to thermal problems, but to problems which are governed by Laplace equations in the fracture and in the surrounding solid. For instance, consider a fracture filled by debris embedded in a porous medium; the flow on the Darcy scale in these two media are governed by elliptic equations with different coefficients. Therefore, all the methodology and results apply to this case as well. The normal resistance and the tangential conductivity of a single fracture with Gaussian or self affine surfaces are systematically studied as functions of the nature of the materials in contact and of the geometrical parameters. Analytical formulae are provided in the lubrication limit for fractures with sinusoidal apertures; these formulae are used to substantiate empirical formulae for resistance and conductivity. Other approximations based on the combination of series and parallel formulae are tested.


    Directory of Open Access Journals (Sweden)

    Stefan Karlsson


    Full Text Available Thermal strengthening of glass is common for many different purposes including architecture, automotive, glasses for solar energy, tableware and occasionally also containers. It is an easy and relatively cheap method to make glasses stronger, however, with an Achilles heel that it can spontaneously fracture without the slightest applied external force. Though, fracture due to applied external force is the most common case, spontaneous fracture is rare. The current paper reviews the literature of spontaneous fracture and NiS inclusions and what kind of mitigation measures that have been done in order to reduce the frequency of spontaneous fracture. Finally is also an outlook for the alternative mitigation measures and their advantages as well as disadvantages. A personal perspective is given in discussions and gives an outlook to the most promising alternative methods to reduce and hopefully eliminate the NiS inclusions. These include multi-functional methods where not only the NiS inclusion issue is solved.

  11. Numerical simulation of thermal fracture in functionally graded ...

    Indian Academy of Sciences (India)

    Sahil Garg

    Abstract. In the present work, element-free Galerkin method (EFGM) has been extended and implemented to simulate thermal fracture in ... has been used in order to extract the stress intensity factors for the simulated problems. The present analysis ... different requirements at different locations within the same component.

  12. Thermal stress fracture in elastic-brittle materials (United States)

    Emery, A. F.


    The reported investigation shows that the assessment of the possibility of the thermal fracture of brittle materials depends upon an accurate evaluation of the thermal stresses and the determination of the resulting stress intensity factors. The stress intensity factors can be calculated in a variety of ways ranging from the very precise to approximate, but only for a limited number of geometries. The main difficulty is related to the determination of the thermal stress field because of its unusual character and its dependence upon boundary conditions at points far from the region of thermal activity. Examination of a number of examples suggests that the best visualization of the thermal stresses and any associated fracture can be made by considering the problem to be the combination of thermal and isothermal problems or by considering that the prime effect of the temperature is in the generation of thermal strains and that the thermal stresses are simply the result of the region trying to accommodate these strains.

  13. Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hai; Plummer, Mitchell; Podgorney, Robert


    Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.

  14. Thermal Drawdown-Induced Flow Channeling in Fractured Geothermal Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Pengcheng; Hao, Yue; Walsh, Stuart D. C.; Carrigan, Charles R.


    We investigate the flow-channeling phenomenon caused by thermal drawdown in fractured geothermal reservoirs. A discrete fracture network-based, fully coupled thermal–hydrological–mechanical simulator is used to study the interactions between fluid flow, temperature change, and the associated rock deformation. The responses of a number of randomly generated 2D fracture networks that represent a variety of reservoir characteristics are simulated with various injection-production well distances. We find that flow channeling, namely flow concentration in cooled zones, is the inevitable fate of all the scenarios evaluated. We also identify a secondary geomechanical mechanism caused by the anisotropy in thermal stress that counteracts the primary mechanism of flow channeling. This new mechanism tends, to some extent, to result in a more diffuse flow distribution, although it is generally not strong enough to completely reverse flow channeling. We find that fracture intensity substantially affects the overall hydraulic impedance of the reservoir but increasing fracture intensity generally does not improve heat production performance. Increasing the injection-production well separation appears to be an effective means to prolong the production life of a reservoir.

  15. Hydromechanical and Thermomechanical Behaviour of Elastic Fractures during Thermal Stimulation of Naturally Fractured Reservoirs (United States)

    Jalali, Mohammadreza; Valley, Benoît


    During the last two decades, incentives were put in place in order to feed our societies in energy with reduced CO2 emissions. Various policies have been considered to fulfill this strategy such as replacing coal by natural gas in power plants, producing electricity using CO2 free resources, and CO2 sequestration as a remediation for large point-source emitters (e.g. oil sands facilities, coal-fired power plants, and cement kilns). Naturally fractured reservoirs (NFRs) are among those geological structures which play a crucial role in the mentioned energy revolution. The behavior of fractured reservoirs during production processes is completely different than conventional reservoirs because of the dominant effects of fractures on fluid flux, with attendant issues of fracture fabric complexity and lithological heterogeneity. The level of complexity increases when thermal effects are taking place - as during the thermal stimulation of these stress-sensitive reservoirs in order to enhance the gas production in tight shales and/or increase the local conductivity of the fractures during the development of enhanced geothermal systems - where temperature is introduced as another degree of freedom in addition to pressure and displacement (or effective stress). Study of these stress-pressure-temperature effects requires a thermo-hydro-mechanical (THM) coupling approach, which considers the simultaneous variation of effective stress, pore pressure, and temperature and their interactions. In this study, thermal, hydraulic and mechanical behavior of partially open and elastic fractures in a homogeneous, isotropic and low permeable porous rock is studied. In order to compare the hydromechanical (HM) and thermomechanical (TM) characteristics of these fractures, three different injection scenarios, i.e. constant isothermal fluid injection rate, constant cooling without any fluid injection and constant cold fluid injection, are considered. Both thermomechanical and hydromechanical

  16. 75 FR 72653 - Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events... (United States)


    ... RIN 3150-AI01 Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal... Regulations (10 CFR) part 50, section 61a to provide alternate fracture toughness requirements for protection...

  17. Single well thermal tracer test, a new experimental set up for characterizing thermal transport in fractured media (United States)

    de La Bernardie, Jérôme; Bour, Olivier; Guihéneuf, Nicolas; Chatton, Eliot; Labasque, Thierry; Longuevergne, Laurent; Le Lay, Hugo; Koch, Floriant; Gerard, Marie-Françoise; Le Borgne, Tanguy


    Thermal transport in fractured media depends on the hydrological properties of fractures and thermal characteristics of rock. Tracer tests using heat as tracer can thus be a good alternative to characterize fractured media for shallow geothermal needs. This study investigates the possibility of implementing a new thermal tracer test set up, the single well thermal tracer test, to characterize hydraulic and thermal transport properties of fractured crystalline rock. The experimental setup is based on injecting hot water in a fracture isolated by a double straddle packer in the borehole while pumping and monitoring the temperature in a fracture crossing the same borehole at greater elevation. One difficulty comes from the fact that injection and withdrawal are achieved in the same borehole involving thermal losses along the injection tube that may disturb the heat recovery signal. To be able to well localize the heat influx, we implemented a Fiber-Optic Distributed Temperature Sensing (FO-DTS) which allows the temperature monitoring with high spatial and temporal resolution (29 centimeters and 30 seconds respectively). Several tests, at different pumping and injection rates, were performed in a crystalline rock aquifer at the experimental site of Ploemeur (H+ observatory network). We show through signal processing how the thermal breakthrough may be extracted thanks to Fiber-Optic distributed temperature measurements. In particular, we demonstrate how detailed distributed temperature measurements were useful to identify different inflows and to estimate how much heat was transported and stored within the fractures network. Thermal breakthrough curves of single well thermal tracer tests were then interpreted with a simple analytical model to characterize hydraulic and thermal characteristics of the fractured media. We finally discuss the advantages of these tests compared to cross-borehole thermal tracer tests.

  18. Mixed Mode Fracture of Plasma Sprayed Thermal Barrier Coatings: Effects of Anisotropy and Heterogeneity (United States)

    Zhu, Dongming; Choi, Sung R.; Ghosn, Louis L.


    The combined mode I-mode II fracture behavior of anisotropic ZrO2-8wt%Y2O3 thermal barrier coatings was determined in asymmetric flexure loading at both ambient and elevated temperatures. A fracture envelope of KI versus KII was determined for the coating material at ambient and elevated temperatures. Propagation angles of fracture as a function of KI/KII were also determined. The mixed-mode fracture behavior of the microsplat coating material was modeled using Finite Element approach to account for anisotropy and micro cracked structures, and predicted in terms of fracture envelope and propagation angle using mixed-mode fracture theories.

  19. Thermal-Hydrologic-Mechanical Behavior of Single Fractures in EGS Reservoirs (United States)

    Zyvoloski, G.; Kelkar, S.; Yoshioka, K.; Rapaka, S.


    Enhanced Geothermal Systems (EGS) rely on the creation a connected fracture system or the enhancement of existing (natural) fractures by hydraulic and chemical treatments. EGS studies at Fenton Hill (New Mexico, USA) and Hijiori (Japan) have revealed that only a limited number of fractures contribute to the effective heat transfer surface area. Thus, the economic viability of EGS depends strongly on the creation and spacing of single fractures in order to efficiently mine heat from given volume of rock. Though there are many similarities between EGS and natural geothermal reservoirs, a major difference between the reservoir types is the (typically) high pumping pressures and induced thermal stresses at the injection wells of an EGS reservoir. These factors can be responsible for fracture dilation/extension and thermal short circuiting and depend strongly on the surrounding state of stress in the reservoir and mechanical properties. We will present results from our study of the thermal-hydrologic-mechanical (THM) behavior of a single fracture in a realistic subsurface stress field. We will show that fracture orientation, the stress environment, fracture permeability structure, and the relationship between permeability changes in a fracture resulting from mechanical displacement are all important when designing and managing an EGS reservoir. Lastly, we present a sensitivity analysis of the important parameters that govern fracture behavior with respect to field measurements. Temperature in high permeability fracture in an EGS reservoir

  20. Thermal drawdown and recovery of singly and multiply fractured hot dry rock reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Wunder, R.; Murphy, H.


    To calculate heat extraction and thermal recovery in hot dry rock geothermal reservoirs, a computer code was written to solve the differential equations for rock-water heat conduction and convection by finite differences. Temperature versus time functions for multiple fractures separated by various spacings are presented in dimensional and in nondimensional plots. The results were specialized for the limiting case of a single fracture in unbounded rock and for the other limiting case where the rock is so extensively fractured that thermal breakthrough phenomena can occur. Fracture temperatures were calculated during the thermal recovery following various extraction periods. For the single-fracture case these temperature recoveries could, with slight approximation, be represented as a single curve depending only upon the ratio of the total elapsed time and the extraction time.

  1. Discrete Modeling of Early-Life Thermal Fracture in Ceramic Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Benjamin W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dolbow, John E. [Duke Univ., Durham, NC (United States); Hales, Jason D. [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Fracturing of ceramic fuel pellets heavily influences performance of light water reactor (LWR) fuel. Early in the life of fuel, starting with the initial power ramp, large thermal gradients cause high tensile hoop and axial stresses in the outer region of the fuel pellets, resulting in the formation of radial and axial cracks. Circumferential cracks form due to thermal gradients that occur when the power is ramped down. These thermal cracks cause the fuel to expand radially, closing the pellet/cladding gap and enhancing the thermal conductance across that gap, while decreasing the effective conductivity of the fuel in directions normal to the cracking. At lower length scales, formation of microcracks is an important contributor to the decrease in bulk thermal conductivity that occurs over the life of the fuel as the burnup increases. Because of the important effects that fracture has on fuel performance, a realistic, physically based fracture modeling capability is essential to predict fuel behavior in a wide variety of normal and abnormal conditions. Modeling fracture within the context of the finite element method, which is based on continuous interpolations of solution variables, has always been challenging because fracture is an inherently discontinuous phenomenon. Work is underway at Idaho National Laboratory to apply two modeling techniques model fracture as a discrete displacement discontinuity to nuclear fuel: The extended finite element method (XFEM), and discrete element method (DEM). XFEM is based on the standard finite element method, but with enhancements to represent discontinuous behavior. DEM represents a solid as a network of particles connected by bonds, which can arbitrarily fail if a fracture criterion is reached. This paper presents initial results applying the aforementioned techniques to model fuel fracturing. This work has initially focused on early life behavior of ceramic LWR fuel. A coupled thermal-mechanical XFEM method that includes

  2. Fracture of a veneered-ZrO2 dental prosthesis from an inner thermal crack

    Directory of Open Access Journals (Sweden)

    Ulrich Lohbauer


    Full Text Available Here we describe the fractographic analysis of a veneer-ZrO2 single-unit dental prosthesis that fractured in a shell-like manner. Analysis of the retrieved fragment revealed that the crack originated in the bulk of the veneer from a thermal flaw located between two layers of the veneering material. Using the measured flaw plane we showed that the conditions of loading at fracture were complex and probably involved important tangential components.

  3. A ductile fracture criterion with Zener-Hollomon parameter of pure molybdenum sheet in thermal forming

    Directory of Open Access Journals (Sweden)

    Wang Chu


    Full Text Available Formability of pure molybdenum in thermal forming process has been greatly improved, but it is still hard to avoid the generation of rupture and other quality defects. In this paper, a ductile fracture criterion of pure molybdenum sheet in thermal forming was established by considering the plastic deformation capacity of material and stress states, which can be used to describe fracture behaviour and critical rupture prediction of pure molybdenum sheet during hot forming process. Based on the isothermal uniaxial tensile tests which performed at 993 to 1143 K with strain rate range from 0.0005 to 0.2 s−1, the material parameters are calculated by the combination method of experiment with FEsimulation. Based on the observation, new fracture criteria can be expressed as a function of Zener-Hollomon parameter. The critical fracture value that calculated by Oyane-Sato criterion increases with increasing temperature and decreasing strain rate. The ductile fracture criterion with Zener-Hollomon parameter of pure molybdenum in thermal forming is proposed.

  4. Phase field modelling of dynamic thermal fracture in the context of irradiation damage

    CERN Document Server

    Schlüter, Alexander; Müller, Ralf; Tomut, Marilena; Trautmann , Christina; Weick, Helmut; Plate, Carolin


    This work presents a continuum mechanics approach to model fracturing processes in brittle materials that are subjected to rapidly applied high-temperature gradients. Such a type of loading typically occurs when a solid is exposed to an intense high-energy particle beam that deposits a large amount of energy into a small sample volume. Given the rapid energy deposition leading to a fast temperature increase, dynamic effects have to be considered. Our existing phase field model for dynamic fracture is thus extended in a way that allows modelling of thermally induced fracture. A finite element scheme is employed to solve the governing partial differential equations numerically. Finally, the functionality of our model is illustrated by two examples.

  5. Scaling capillary imbibition during static thermal and dynamic fracture flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Babadagli, T. [Department of Petroleum and Min. Res. Eng., College of Engineering, Sultan Qaboos University, P.O. Box 33, Al Khod, Muscat (Oman)


    To incorporate the effect of temperature, previously reported scaling formulations were modified considering the wettability, change in oil properties, and thermal expansion. The results of static imbibition experiments conducted using different types of heavy-oil samples at different temperatures up to 90 C were used to verify the formulation. The modified scaling formulations responded well if the thermal expansion effect is included, except in high-temperature crude oil imbibition cases. The results obtained through water injection experiments in artificially fractured core samples with matrix permeabilities ranging from 300 to 0.075 mD were used to verify the numerical model of core scale displacements. Then the convergence constant in Aranofsky's abstract recovery-time relationship was correlated to an imbibition group consisting of the injection rate and matrix properties. Three different formulations were presented and tested. Good agreement with the experimental observations could be achieved when the wettability and permeability of the matrix and the flow rate in fracture is included in the formulations. When the matrix size is included in the regression analysis, not all correlation types yielded a good agreement with the experimental data. This study will provide an insight into the scaling of the laboratory scale experiments to the reservoir conditions and constitute a base to define matrix fracture interaction in numerical models dealing with fractured reservoir modeling.

  6. The mechanics and physics of fracturing: application to thermal aspects of crack propagation and to fracking. (United States)

    Cherepanov, Genady P


    By way of introduction, the general invariant integral (GI) based on the energy conservation law is presented, with mention of cosmic, gravitational, mass, elastic, thermal and electromagnetic energy of matter application to demonstrate the approach, including Coulomb's Law generalized for moving electric charges, Newton's Law generalized for coupled gravitational/cosmic field, the new Archimedes' Law accounting for gravitational and surface energy, and others. Then using this approach the temperature track behind a moving crack is found, and the coupling of elastic and thermal energies is set up in fracturing. For porous materials saturated with a fluid or gas, the notion of binary continuum is used to introduce the corresponding GIs. As applied to the horizontal drilling and fracturing of boreholes, the field of pressure and flow rate as well as the fluid output from both a horizontal borehole and a fracture are derived in the fluid extraction regime. The theory of fracking in shale gas reservoirs is suggested for three basic regimes of the drill mud permeation, with calculating the shape and volume of the local region of the multiply fractured rock in terms of the pressures of rock, drill mud and shale gas. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  7. Evidence for tectonic, lithologic, and thermal controls on fracture system geometries in an andesitic high-temperature geothermal field (United States)

    Massiot, Cécile; Nicol, Andrew; McNamara, David D.; Townend, John


    Analysis of fracture orientation, spacing, and thickness from acoustic borehole televiewer (BHTV) logs and cores in the andesite-hosted Rotokawa geothermal reservoir (New Zealand) highlights potential controls on the geometry of the fracture system. Cluster analysis of fracture orientations indicates four fracture sets. Probability distributions of fracture spacing and thickness measured on BHTV logs are estimated for each fracture set, using maximum likelihood estimations applied to truncated size distributions to account for sampling bias. Fracture spacing is dominantly lognormal, though two subordinate fracture sets have a power law spacing. This difference in spacing distributions may reflect the influence of the andesitic sequence stratification (lognormal) and tectonic faults (power law). Fracture thicknesses of 9-30 mm observed in BHTV logs, and 1-3 mm in cores, are interpreted to follow a power law. Fractures in thin sections (˜5 μm thick) do not fit this power law distribution, which, together with their orientation, reflect a change of controls on fracture thickness from uniform (such as thermal) controls at thin section scale to anisotropic (tectonic) at core and BHTV scales of observation. However, the ˜5% volumetric percentage of fractures within the rock at all three scales suggests a self-similar behavior in 3-D. Power law thickness distributions potentially associated with power law fluid flow rates, and increased connectivity where fracture sets intersect, may cause the large permeability variations that occur at hundred meter scales in the reservoir. The described fracture geometries can be incorporated into fracture and flow models to explore the roles of fracture connectivity, stress, and mineral precipitation/dissolution on permeability in such andesite-hosted geothermal systems.

  8. E’’ Raman Mode in Thermal Strain-Fractured CVD-MoS2

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    Di Wu


    Full Text Available Molybdenum disulfide (MoS2 has recently attracted considerable interests due to its unique properties and potential applications. Chemical vapor deposition (CVD method is used widely to grow large-area and high-quality MoS2 single crystals. Here, we report our investigation on thermal strain-fractured (SF single crystalline MoS2, oxidation-fractured MoS2, and normal MoS2 by atomic force microscopy (AFM, Raman and photoluminescence (PL measurements. Several new Raman modes are observed for SF-MoS2. The band gap of SF-MoS2 is enlarged by 150 meV and the PL intensity is reduced substantially. These results imply that a structural transformation occurs in SF-MoS2. Our findings here are useful for the design of MoS2-based nanocatalysts with relative high catalytic activity.

  9. Insights about fracture shape and aperture from push-pull thermal tracer tests achieved at different scales (United States)

    Klepikova, Maria V.; Le Borgne, Tanguy; Bour, Olivier; Hochreutener, Rebecca; Lavenant, Nicolas


    The prediction of transport patterns in fractured media is a challenging task. Different transport mechanisms are generally contributing: dispersion at fracture scale related to aperture variability, dispersion at network scale due to transport in different flowpaths and matrix diffusion. It is however difficult to know which mechanism is dominant. In this study we test the interest of heat tracer tests for providing new constraints on transport in fractured media by interpreting three push-pull tests of different duration. A series of heat and solute push-pull tracer test with Dirac-type injection was conducted in fractured aquifer of Ploemeur, France. The comparison of solute and heat breakthrough curves shows that due to thermal loss to the rock matrix temperature recovery peak arrives earlier than concentration peak. Moreover, the peak is significantly smaller for temperature recovery while it exhibits a longest tailing. Finally, we found that the recovered peak temperature decreases with scale and has a power law slope of -1 on a log-log plot. By means of flow and heat numerical model, we investigate the relevance of different conceptual models: single 'plate', 'tube' and 'ellipse' homogeneous fracture models at different scales. For all tested fracture geometries temperature breakthrough curves were found to be sensitive to fracture aperture. An 'elliptical tube' fracture model was found to provide the best fit to the data and based on this model, we were able to estimate the aperture of the fracture in the present case. Moreover, the comparison of experimental breakthrough curves and modelling results also suggests that the effective fracture aperture may increase with scale. This work emphasizes that multiple-scale push-pull thermal tests can provide valuable insights on fracture geometry and fracture aperture.

  10. Numerical Modelling of Thermal Convection Related to Fracture Permeability - Implications for Geothermal Exploration and Basin Modelling (United States)

    Lipsey, Lindsay; van Wees, Jan-Diederik; Pluymaekers, Maarten; Cloetingh, Sierd


    Thermal anomalies in deep sedimentary settings are largely controlled by fluid circulation within permeable zones. Convection is of particular interest in geothermal exploration, as it creates areas with anomalously high temperatures at shallow depths. Recent work on the temperature distribution in the Dutch subsurface revealed a thermal anomaly at the Luttelgeest-01 (LTG-01) at 4-5 km depth, which could be explained by thermal convection. Temperature measurements show a shift to higher temperatures at depths greater than 4000 m, corresponding the Dinantian carbonates. In order for convective heat transport to explain the anomaly, there must also be sufficient permeability. Rayleigh number calculations show that convection may be possible within the Dinantian carbonate layer, depending on its thickness, permeability and geothermal gradient. For example, an average permeability of 60 mD permits convection in a 600 m aquifer, given a geothermal gradient of 31°C/km. If the permeability is reduced to 20 mD, convection can only occur where the thickness of the aquifer is greater than 900 m. Interestingly, numerical simulations were able to come within 5-10 mD of the theoretical minimum permeability values calculated for each scenario. 3D numerical simulations provide insight on possible flow and thermal structures within the fractured carbonate interval, as well as illustrate the role of permeability on the timing of convection onset, convection cell structure development and the resulting temperature patterns. The development and number of convection cells is very much a time dependent process. Many cells may develop in the beginning of simulations, but they seem to gradually converge until steady state is reached. The shape of convective upwellings varies from roughly circular or hexagonal to more elongated upwellings and downwellings. Furthermore, the geometric aspects of the carbonate platform itself likely control the shape and location of upwellings, as well as

  11. Modeling of thermally driven hydrological processes in partially saturated fractured rock (United States)

    Tsang, Y. W.; Birkholzer, J. T.; Mukhopadhyay, S.


    This paper is a review of the research that led to an in-depth understanding of flow and transport processes under strong heat stimulation in fractured, porous rock. It first describes the anticipated multiple processes that come into play in a partially saturated, fractured porous volcanic tuff geological formation when it is subject to a heat source such as that originating from the decay of radionuclides. The rationale is then given for numerical modeling being a key element in the study of multiple processes that are coupled. The paper outlines how the conceptualization and the numerical modeling of the problem evolved, progressing from the simplified to the more realistic. Examples of numerical models are presented so as to illustrate the advancement and maturation of the research over the last 2 decades. The most recent model applied to in situ field thermal tests is characterized by (1) incorporation of a full set of thermal-hydrological processes into a numerical simulator, (2) realistic representation of the field test geometry in three dimensions, and (3) use of site-specific characterization data for model inputs. Model predictions were carried out prior to initiation of data collection, and the model results were compared to diverse sets of measurements. The approach of close integration between modeling and field measurements has yielded a better understanding of how coupled thermal hydrological processes produce redistribution of moisture within the rock, which affects local permeability values and subsequently the flow of liquid and gases. The fluid flow, in turn, will change the temperature field. We end with a note on future research opportunities, specifically those incorporating chemical, mechanical, and microbiological factors into the study of thermal and hydrological processes.

  12. Fracture behavior of reinforced aluminum alloy matrix composites using thermal imaging tools (United States)

    Avdelidis, N. P.; Exarchos, D.; Vazquez, P.; Ibarra-Castanedo, C.; Sfarra, S.; Maldague, X. P. V.; Matikas, T. E.


    In this work the influence of the microstructure at the vicinity of the interface on the fracture behavior of particulate-reinforced aluminum alloy matrix composites (Al/SiCp composites) is studied by using thermographic tools. In particular, infrared thermography was used to monitor the plane crack propagation behavior of the materials. The deformation of solid materials is almost always accompanied by heat release. When the material becomes deformed or is damaged and fractured, a part of the energy necessary to initiate and propagate the damage is transformed in an irreversible way into heat. The thermal camera detects the heat wave, generated by the thermo-mechanical coupling and the intrinsic dissipated energy during mechanical loading of the sample. By using an adapted detector, thermography records the two dimensional "temperature" field as it results from the infrared radiation emitted by the object. The principal advantage of infrared thermography is its noncontact, non-destructive character. This methodology is being applied to characterise the fracture behavior of the particulate composites. Infrared thermography is being used to monitor the plane crack propagation behavior of such materials. Furthermore, an innovative approach to use microscopic measurements using IR microscopic lenses was attempted, in order to enable smaller features (in the micro scale) to be imaged with accuracy and assurance.

  13. Structure, thermal and fracture mechanical properties of benzoxazine-modified amine-cured DGEBA epoxy resins

    Directory of Open Access Journals (Sweden)


    Full Text Available First, traditional diamine hardeners of epoxy resins (EP were checked as potential accelerators for the benzoxazine (BOX homopolymerization. It was established that the acceleration effect depends on both the type and amount of the diamine compounds. In the follow-up work amine-curable diglycidyl ether bisphenol A (DGEBA type EP was modified with BOX keeping the EP/BOX ratio constant (75/25 wt.%. The amine hardeners, added in the EP in stoichiometric amounts, were of aliphatic and aromatic nature, viz. diethylenetriamine (DETA, 4,4'-diaminodiphenyl methane (DDM, and their 1/1 mixture. The thermal, viscoelastic, flexural and fracture mechanical properties of the EP/BOX hybrids were determined and compared to those of the reference EPs. Based on dynamic-mechanical thermal analysis and atomic force microscopy the formation of co-network between EP and BOX was concluded. Homopolymerized BOX was built in the network in nanoscaled inclusions and it was associated with internal antiplasticization. Incorporation of BOX improved the charring, enhanced the flexural modulus and strength, and reduced the glass transition of the parent EP. The fracture toughness and energy were not improved by hybridization with BOX.

  14. Effects of heat transfer coefficient treatments on thermal shock fracture prediction for LWR fuel claddings in water quenching

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youho; Lee, Jeong Ik; Cheon, Hee [KAIST, Daejeon (Korea, Republic of)


    Accurate modeling of thermal shock induced stresses has become ever most important to emerging accident-tolerant ceramic cladding concepts, such as silicon carbide (SiC) and SiC coated zircaloy. Since fractures of ceramic (entirely ceramic or coated) occur by excessive tensile stresses with linear elasticity, modeling transient stress distribution in the material provides a direct indication of the structural integrity. Indeed, even for the current zircaloy cladding material, the oxide layer formed on the surface - where cracks starts to develop upon water quenching - essentially behaves as a brittle ceramic. Hence, enhanced understanding of thermal shock fracture of a brittle material would fundamentally contribute to safety of nuclear reactors for both the current fuel design and that of the coming future. Understanding thermal shock fracture of a brittle material requires heat transfer rate between the solid and the fluid for transient temperature fields of the solid, and structural response of the solid under the obtained transient temperature fields. In water quenching, a solid experiences dynamic time-varying heat transfer rates with phase changes of the fluid over a short quenching period. Yet, such a dynamic change of heat transfer rates during the water quenching transience has been overlooked in assessments of mechanisms, predictability, and uncertainties for thermal shock fracture. Rather, a time-constant heat transfer coefficient, named 'effective heat transfer coefficient' has become a conventional input to thermal shock fracture analysis. No single constant heat transfer could suffice to depict the actual stress evolution subject to dynamic heat transfer coefficient changes with fluid phase changes. Use of the surface temperature dependent heat transfer coefficient will remarkably increase predictability of thermal shock fracture of brittle materials and complete the picture of stress evolution in the quenched solid. The presented result


    Energy Technology Data Exchange (ETDEWEB)

    Robert Podgorney; Chuan Lu; Hai Huang


    Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions of EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability

  16. Fracture evaluation of thermally sprayed coatings in dependence on cohesive strength (United States)

    Schubert, J.; Česánek, Z.


    Measuring the cohesive strength of thermally sprayed coatings is relatively difficult matter, which can be accessed in many directions. This issue is nowadays solved by use of Scratch test method. This method is not completely sufficient for the cohesive strength testing because the coating is under load of combined stresses during the Scratch test. The reason to develop this method was need for exact measurement of tensile cohesion toughness of thermally sprayed coatings, which could provide results as close to a classic tensile test as possible. Another reason for development of this method was the impossibility of direct comparison with results obtained by other methods. Tested coatings were prepared using HP / HVOF (Stellite 6, NiCrBSi, CrC-NiCr and Hastelloy C-276). These coatings were selected as commonly used in commercial sector and also on because of rising customer demand for ability to provide such coating characteristics. The tested coatings were evaluated in terms of cohesive strength (method based on tensile strength test). Final fractures were evaluated by optical microscopy together with scanning electron microscopy and EDS analysis. As expected higher cohesive strength showed metallic coatings with top results of coating Stellite 6. Carbide coatings showed approximately third of the cohesion strength in comparison with metal based coating.

  17. Effect of long-term thermal aging on the fracture toughness of austenitic stainless steel base and weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Huang, F.F.


    Compact tension specimens taken from FFTF primary piping materials (Type 316 stainless steel (SS) and 16-8-2 SS weld metal) and from reactor vessel materials (304 SS and 308 SS weld metal) were heated in laboratory furnaces from 100,000 hours. Fracture toughness testing was performed on these specimens, which are 7.62- and 25.4-mm thick, respectively at the aging temperature (482 and 427 degrees). Results were analyzed with the multiple-specimen method. Thermal aging continues to reduce the fracture toughness of FFTF component materials. Results show that thermal aging has a strong effect on the toughness degradation of weld metals, particularly for 16-8-2 SS weld whose aged/unaged Jc ratio is only 0.31 after 100,000-hour aging. The fracture toughness of the 308 and 16-8-2 SS weld metals fluctuated during 20,000 to 50,000-hour aging but deteriorated as the aging time increased to 100,000 hours; the toughness degradation is significant. Fracture control based on a fracture mechanics approach should be considered

  18. Fracture


    Bourdin, Blaise; Francfort, Gilles A.


    These notes begin with a review of the mainstream theory of brittle fracture, as it has emerged from the works of Griffi th and Irwin. We propose a re-formulation of that theory within the confi nes of the calculus of variations, focussing on crack path prediction. We then illustrate the various possible minimality criteria in a simple 1d-case as well as in a tearing experiment and discuss in some details the only complete mathematical formulation so far, that is that where global minimality ...

  19. Fracture Toughness of Z3CN20.09M Cast Stainless Steel with Long-Term Thermal Aging (United States)

    Yu, Weiwei; Yu, Dunji; Gao, Hongbo; Xue, Fei; Chen, Xu


    Accelerated thermal aging tests were performed at 400 °C for nearly 18,000 h on Z3CN20.09M cast stainless steel which was used for primary coolant pipes of nuclear power plants. A series of Charpy impact tests were conducted on Z3CN20.09M after different long-term thermal aging time. The test results indicated that the Charpy impact energy of Z3CN20.09M cast stainless steel decreased rapidly at an early stage and then almost saturated after thermal aging of 10,000 h. Furthermore, J-resistance curves were measured for CT specimens of longitudinal and circumferential pipe orientations. It showed that there was no obvious difference in the fracture characteristics of Z3CN20.09M in different sampling directions. In addition, the observed stretch zone width (SZW) revealed that the value of initiation fracture toughness J SZW was significantly lower than that of fracture toughness J IC, indicating a low actual crack initiation energy due to long-term thermal aging.

  20. Expert tibia nail for subtrochanteric femoral fracture to prevent thermal injury

    Directory of Open Access Journals (Sweden)

    Kyung-Jae Lee


    Conclusion: Expert tibia nail may be considered one of the treatment options for subtrochanteric femoral fracture with narrow medullary canal. We also emphasize the importance of preoperative evaluation of the medullary canal size for these risky fractures.

  1. 75 FR 10410 - Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events... (United States)


    ... COMMISSION 10 CFR Part 50 RIN 3150-AI01 Alternate Fracture Toughness Requirements for Protection Against... (75 FR 13), that amends the NRC's regulations to provide alternate fracture toughness requirements for... adding Table 7 directly after Table 6 to read as follows: Sec. 50.61a Alternate fracture toughness...

  2. Medical thermography (digital infrared thermal imaging - DITI) in paediatric forearm fractures - A pilot study. (United States)

    Ćurković, S; Antabak, A; Halužan, D; Luetić, T; Prlić, I; Šiško, J


    Trauma is the most common cause of hospitalisation in children, and forearm fractures comprise 35% of all paediatric fractures. One-third of forearm fractures are distal forearm fractures, which are the most common fractures in the paediatric population. This type of fracture represents an everyday problem for the paediatric surgeon. The three phases of fracture healing in paediatric trauma are associated with skin temperature changes that can be measured and then compared with standard plain radiographs of visible callus formation, and eventually these methods can be used in everyday practice. Thermographic assessment of temperature distribution within the examined tissues enables a quick, non-contact, non-invasive measurement of their temperature. Medical thermography is used as a screening method in other parts of medicine, but the use of this method in traumatology has still not been researched. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. The influence of chemistry concentration on the fracture risk of a reactor pressure vessel subjected to pressurized thermal shocks

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pin-Chiun [Institute of Nuclear Engineering and Science, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China); Chou, Hsoung-Wei, E-mail: [Institute of Nuclear Energy Research, Taoyuan 32546, Taiwan, ROC (China); Ferng, Yuh-Ming [Institute of Nuclear Engineering and Science, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China)


    Highlights: • Probabilistic fracture mechanics method was used to analyze a reactor pressure vessel. • Effects of copper and nickel contents on RPV fracture probability under PTS were investigated and discussed. • Representative PTS transients of Beaver Valley nuclear power plant were utilized. • The range of copper and nickel contents of the RPV materials were suggested. • With different embrittlement levels the dominated PTS category is different. - Abstract: The radiation embrittlement behavior of reactor pressure vessel shell is influenced by the chemistry concentration of metal materials. This paper aims to study the effects of copper and nickel content variations on the fracture risk of pressurized water reactor (PWR) pressure vessel subjected to pressurized thermal shock (PTS) transients. The probabilistic fracture mechanics (PFM) code, FAVOR, which was developed by the Oak Ridge National Laboratory in the United States, is employed to perform the analyses. A Taiwan domestic PWR pressure vessel assumed with varied copper and nickel contents of beltline region welds and plates is investigated in the study. Some PTS transients analyzed from Beaver Valley Unit 1 for establishing the U.S. NRC's new PTS rule are applied as the loading condition. It is found that the content variation of copper and nickel will significantly affect the radiation embrittlement and the fracture probability of PWR pressure vessels. The results can be regarded as the risk incremental factors for comparison with the safety regulation requirements on vessel degradation as well as a reference for the operation of PWR plants in Taiwan.

  4. Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C


    DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption in crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with

  5. 75 FR 5495 - Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events... (United States)


    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION 10 CFR Part 50 RIN 3150-AI01 Alternate Fracture Toughness Requirements for Protection Against... (75 FR 13), that amends the NRC's regulations to provide alternate fracture toughness requirements for...

  6. Mode I fracture toughness behavior of hydro-thermally aged carbon fibre reinforced DGEBA-HHPA-PES systems (United States)

    Alessi, Sabina; Pitarresi, Giuseppe; Spadaro, Giuseppe; Tumino, Davide


    In this work the Mode I fracture toughness behavior of unidirectional CFRP laminates is investigated by means of Double Cantilever Beam (DCB) tests. The composite samples were manufactured by thermal curing after impregnation of a Carbon fabric with a DGEBA epoxy and anhydride HHPA curing agent. One resin batch was also mixed with a PES thermoplastic monomer to enhance the matrix toughness. Two lots of samples, toughened and untoughened, were then left to soak in hot water to achieve various degrees of aging. The influence of matrix toughening and hydrothermal aging on the delamination behavior of the composite have then been assessed and correlated with characterization data from Dynamic Mechanical Thermal Analysis (DMTA) and Scanning Electron Microscopy (SEM).

  7. Comparisons of the composition and biogeographic distribution of the bacterial communities occupying South African thermal springs with those inhabiting deep subsurface fracture water. (United States)

    Magnabosco, Cara; Tekere, Memory; Lau, Maggie C Y; Linage, Borja; Kuloyo, Olukayode; Erasmus, Mariana; Cason, Errol; van Heerden, Esta; Borgonie, Gaetan; Kieft, Thomas L; Olivier, Jana; Onstott, Tullis C


    South Africa has numerous thermal springs that represent topographically driven meteoric water migrating along major fracture zones. The temperature (40-70°C) and pH (8-9) of the thermal springs in the Limpopo Province are very similar to those of the low salinity fracture water encountered in the South African mines at depths ranging from 1.0 to 3.1 km. The major cation and anion composition of these thermal springs are very similar to that of the deep fracture water with the exception of the dissolved inorganic carbon and dissolved O2, both of which are typically higher in the springs than in the deep fracture water. The in situ biological relatedness of such thermal springs and the subsurface fracture fluids that feed them has not previously been evaluated. In this study, we evaluated the microbial diversity of six thermal spring and six subsurface sites in South Africa using high-throughput sequencing of 16S rRNA gene hypervariable regions. Proteobacteria were identified as the dominant phylum within both subsurface and thermal spring environments, but only one genera, Rheinheimera, was identified among all samples. Using Morisita similarity indices as a metric for pairwise comparisons between sites, we found that the communities of thermal springs are highly distinct from subsurface datasets. Although the Limpopo thermal springs do not appear to provide a new window for viewing subsurface bacterial communities, we report that the taxonomic compositions of the subsurface sites studied are more similar than previous results would indicate and provide evidence that the microbial communities sampled at depth are more correlated to subsurface conditions than geographical distance.

  8. Monitoring thermal processes in low-permeability fractured media using fibre-optics distributed temperature sensing (FO-DTS) (United States)

    Brixel, Bernard; Klepikova, Maria; Jalali, Mohammadreza; Loew, Simon; Amann, Florian


    Fibre-optics distributed temperature sensing (FO-DTS) systems constitute arguably one of the main significant advances in the development of modern monitoring techniques in field hydrogeology, both for shallow (e.g. quantification of surface water-groundwater interactions) and deeper applications (borehole temperature monitoring). Deployment of FO-DTS monitoring systems in boreholes has notably allowed further promoting the use of temperature as a tracer to improve the characterization of heterogeneous media, with a strong focus on permeable environments such as shallow unconsolidated aquifers and/or highly-fractured rocks, generally found close to ground surface. However, applying this technology to low-permeability media, as in the case of intact rock mass intersected by isolated, discrete fractures still remains a challenge, perhaps explaining the limited number of field results reported in the scientific literature to date. Yet, understanding the transport, storage and exchange of heat in deep, low-permeability crystalline rocks is critical to many scientific and engineering research topics and applications, including for example deep geothermal energy (DGE). In the present contribution, we describe the use and application of FO-DTS monitoring to a broad range of processes, varying from the propagation and persistence of thermal anomalies (both natural and induced) to the monitoring of the curing of epoxy resin and cement grouts along the annular space of boreholes designed for monitoring discrete, packed-off zones. All data provided herein has been collected as part of a multi-disciplinary research program on hydraulic stimulation and deep geothermal energy carried out at the Grimsel Test Site (GTS), an underground rock laboratory located in the Aar massif, in the Swiss Alps. Through these examples, we illustrate the importance of understanding the spatial and temporal variations of local thermal regimes when planning to monitoring boreholes temperatures

  9. Flexible parallel implicit modelling of coupled thermal-hydraulic-mechanical processes in fractured rocks (United States)

    Cacace, Mauro; Jacquey, Antoine B.


    Theory and numerical implementation describing groundwater flow and the transport of heat and solute mass in fully saturated fractured rocks with elasto-plastic mechanical feedbacks are developed. In our formulation, fractures are considered as being of lower dimension than the hosting deformable porous rock and we consider their hydraulic and mechanical apertures as scaling parameters to ensure continuous exchange of fluid mass and energy within the fracture-solid matrix system. The coupled system of equations is implemented in a new simulator code that makes use of a Galerkin finite-element technique. The code builds on a flexible, object-oriented numerical framework (MOOSE, Multiphysics Object Oriented Simulation Environment) which provides an extensive scalable parallel and implicit coupling to solve for the multiphysics problem. The governing equations of groundwater flow, heat and mass transport, and rock deformation are solved in a weak sense (either by classical Newton-Raphson or by free Jacobian inexact Newton-Krylow schemes) on an underlying unstructured mesh. Nonlinear feedbacks among the active processes are enforced by considering evolving fluid and rock properties depending on the thermo-hydro-mechanical state of the system and the local structure, i.e. degree of connectivity, of the fracture system. A suite of applications is presented to illustrate the flexibility and capability of the new simulator to address problems of increasing complexity and occurring at different spatial (from centimetres to tens of kilometres) and temporal scales (from minutes to hundreds of years).

  10. Dense Non Aqueous Phase Liquid (DNAPL) Removal from Fractured Rock using Thermal Conductive Heating (TCH) (United States)


    may include thermal destruction by oxidation and pyrolysis near heating elements (for thermal conductive heating) at temperatures around 400Ε is used for enhanced oil recovery applications to depths >1,000 ft and for volumes exceeding 100,000 cubic yards (yd3). • pdf . Heron, G., R.S. Baker, J.M. Bierschenk, and J.C. LaChance, 2006. Heat it All the Way - Mechanisms and

  11. A study on the fracture mechanism of smart composite under thermal shock cycles using AE technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.K.; Lee, S.P. [School of Mechanical Engineering, Dongeui Univ., Busan (Korea); Park, Y.C. [School of Mechanical Engineering, Donga Univ., Busan (Korea)


    A smart material is used as spectacle frames and brassiere frames, and partly in medical supplies because of its shape memory effect. The smart composite can be used on the wing of an airplane instead of the existing aluminium to control crack propagation. In this study, the smart composite was fabricated by a hot press method. TiNi alloy as reinforcement and Al6061 as matrix were used, respectively. The mechanical properties of the smart composite under thermal shock cycles were evaluated. In addition, acoustic emission techniques were also used to clarify the damage behavior of the smart composite under thermal shock cycles nondestructively. (orig.)

  12. Thermal hydraulic-Mechanic Integrated Simulation for Advanced Cladding Thermal Shock Fracture Analysis during Reflood Phase in LBLOCA

    Energy Technology Data Exchange (ETDEWEB)

    Son, Seong Min; Lee, You Ho; Cho, Jae Wan; Lee, Jeong Ik [KAERI, Daejeon (Korea, Republic of)


    This study suggested thermal hydraulic-mechanical integrated stress based methodology for analyzing the behavior of ATF type claddings by SiC-Duplex cladding LBLOCA simulation. Also, this paper showed that this methodology could predict real experimental result well. That concept for enhanced safety of LWR called Advanced Accident-Tolerance Fuel Cladding (ATF cladding, ATF) is researched actively. However, current nuclear fuel cladding design criteria for zircaloy cannot be apply to ATF directly because those criteria are mainly based on limiting their oxidation. So, the new methodology for ATF design criteria is necessary. In this study, stress based analysis methodology for ATF cladding design criteria is suggested. By simulating LBLOCA scenario of SiC cladding which is the one of the most promising candidate of ATF. Also we'll confirm our result briefly through comparing some facts from other experiments. This result is validating now. Some of results show good performance with 1-D failure analysis code for SiC fuel cladding that already developed and validated by Lee et al,. It will present in meeting. Furthermore, this simulation presented the possibility of understanding the behavior of cladding deeper. If designer can predict the dangerous region and the time precisely, it may be helpful for designing nuclear fuel cladding geometry and set safety criteria.

  13. Synchrotron tomographic quantification of strain and fracture during simulated thermal maturation of an organic-rich shale, UK Kimmeridge Clay (United States)

    Figueroa Pilz, Fernando; Dowey, Patrick J.; Fauchille, Anne-Laure; Courtois, Loic; Bay, Brian; Ma, Lin; Taylor, Kevin G.; Mecklenburgh, Julian; Lee, Peter D.


    Analyzing the development of fracture networks in shale is important to understand both hydrocarbon migration pathways within and from source rocks and the effectiveness of hydraulic stimulation upon shale reservoirs. Here we use time-resolved synchrotron X-ray tomography to quantify in four dimensions (3-D plus time) the development of fractures during the accelerated maturation of an organic-rich mudstone (the UK Kimmeridge Clay), with the aim of determining the nature and timing of crack initiation. Electron microscopy (EM, both scanning backscattered and energy dispersive) was used to correlatively characterize the microstructure of the sample preheating and postheating. The tomographic data were analyzed by using digital volume correlation (DVC) to measure the three-dimensional displacements between subsequent time/heating steps allowing the strain fields surrounding each crack to be calculated, enabling crack opening modes to be determined. Quantification of the strain eigenvectors just before crack propagation suggests that the main mode driving crack initiation is the opening displacement perpendicular to the bedding, mode I. Further, detailed investigation of the DVC measured strain evolution revealed the complex interaction of the laminar clay matrix and the maximum principal strain on incipient crack nucleation. Full field DVC also allowed accurate calculation of the coefficients of thermal expansion (8 × 10-5/°C perpendicular and 6.2 × 10-5/°C parallel to the bedding plane). These results demonstrate how correlative imaging (using synchrotron tomography, DVC, and EM) can be used to elucidate the influence of shale microstructure on its anisotropic mechanical behavior.

  14. Effects of Thermal Aging on Material Properties, Stress Corrosion Cracking, and Fracture Toughness of AISI 316L Weld Metal (United States)

    Lucas, Timothy; Forsström, Antti; Saukkonen, Tapio; Ballinger, Ronald; Hänninen, Hannu


    Thermal aging and consequent embrittlement of materials are ongoing issues in cast stainless steels, as well as duplex, and high-Cr ferritic stainless steels. Spinodal decomposition is largely responsible for the well-known "748 K (475 °C) embrittlement" that results in drastic reductions in ductility and toughness in these materials. This process is also operative in welds of either cast or wrought stainless steels where δ-ferrite is present. While the embrittlement can occur after several hundred hours of aging at 748 K (475 °C), the process is also operative at lower temperatures, at the 561 K (288 °C) operating temperature of a boiling water reactor (BWR), for example, where ductility reductions have been observed after several tens of thousands of hours of exposure. An experimental program was carried out in order to understand how spinodal decomposition may affect changes in material properties in Type 316L BWR piping weld metals. The study included material characterization, nanoindentation hardness, double-loop electrochemical potentiokinetic reactivation (DL-EPR), Charpy-V, tensile, SCC crack growth, and in situ fracture toughness testing as a function of δ-ferrite content, aging time, and temperature. SCC crack growth rates of Type 316L stainless steel weld metal under simulated BWR conditions showed an approximate 2 times increase in crack growth rate over that of the unaged as-welded material. In situ fracture toughness measurements indicate that environmental exposure can result in a reduction of toughness by up to 40 pct over the corresponding at-temperature air-tested values. Material characterization results suggest that spinodal decomposition is responsible for the degradation of material properties measured in air, and that degradation of the in situ properties may be a result of hydrogen absorbed during exposure to the high-temperature water environment.

  15. Enhancement of the antimicrobial properties of orthorhombic molybdenum trioxide by thermal induced fracturing of the hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Shafaei, Shahram; Van Opdenbosch, Daniel [Technische Universität München (TUM), Chair for Biogenic Polymers, Schulgasse 16, D-94315 Straubing (Germany); Fey, Tobias [Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Materials Science and Engineering 3: Glass and Ceramics, Martensstraße 5, D-91058 Erlangen (Germany); Koch, Marcus; Kraus, Tobias [INM, Leibniz Institute for New Materials, Campus D2 2, D-66123 Saarbrücken (Germany); Guggenbichler, Josef Peter [AMiSTec GmbH & Co. KG, Leitweg 23, A-6345 Kössen (Austria); Zollfrank, Cordt, E-mail: [Technische Universität München (TUM), Chair for Biogenic Polymers, Schulgasse 16, D-94315 Straubing (Germany)


    The oxides of the transition metal molybdenum exhibit excellent antimicrobial properties. We present the preparation of molybdenum trioxide dihydrate (MoO{sub 3} × 2H{sub 2}O) by an acidification method and demonstrate the thermal phase development and morphological evolution during and after calcination from 25 °C to 600 °C. The thermal dehydration of the material was found to proceed in two steps. Microbiological roll-on tests using Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were performed and exceptional antimicrobial activities were determined for anhydrous samples with orthorhombic lattice symmetry and a large specific surface area. The increase in the specific surface area is due to crack formation and to the loss of the hydrate water after calcination at 300 °C. The results support the proposed antimicrobial mechanism for transition metal oxides, which based on a local acidity increase as a consequence of the augmented specific surface area. - Highlights: • Molybdenum trioxide dihydrate (MoO{sub 3} × 2H{sub 2}O) and anhydrous MoO{sub 3} after calcination exhibit exceptional antimicrobial activities • Especially the orthorhombic samples with a large specific surface area show excellent antimicrobial properties. • The increased specific surface area is due to crack formation and to loss of hydrate water after calcination at 300 °C. • Increased a local acidity as a consequence of the augmented surface area is related to the antimicrobial characteristics.

  16. Estimation of fracture parameters in foam core materials using thermal techniques

    DEFF Research Database (Denmark)

    Dulieu-Barton, J. M.; Berggreen, Christian; Boyenval Langlois, C.


    The paper presents some initial work on establishing the stress state at a crack tip in PVC foam material using a non-contact infra-red technique known as thermoelastic stress analysis (TSA). A parametric study of the factors that may affect the thermoelastic response of the foam material...... is described. A mode I simulated crack in the form of a machined notch is used to establish the feasibility of the TSA approach to derive stress intensity factors for the foam material. The overall goal is to demonstrate that thermal techniques have the ability to provide deeper insight into the behaviour...... of the cracks in foam and the potential to determine stress intensity factors....

  17. Nose fracture (United States)

    Fracture of the nose; Broken nose; Nasal fracture; Nasal bone fracture; Nasal septal fracture ... A fractured nose is the most common fracture of the face. It most ... occurs with other fractures of the face. Nose injuries and neck ...

  18. Skull fracture (United States)

    Basilar skull fracture; Depressed skull fracture; Linear skull fracture ... Skull fractures may occur with head injuries . The skull provides good protection for the brain. However, a severe impact ...

  19. X-231A demonstration of in-situ remediation of DNAPL compounds in low permeability media by soil fracturing with thermally enhanced mass recovery or reactive barrier destruction

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L. [Oak Ridge National Lab., TN (United States)]|[Colorado School of Mines, Golden, CO (United States). Environmental Science and Engineering Div.; Lowe, K.S. [Oak Ridge National Lab., Grand Junction, CO (United States). Life Sciences Div.; Murdoch, L.D. [FRx, Inc., Cincinnati, OH (United States)]|[Clemson Univ., SC (United States); Slack, W.W. [FRx, Inc., Cincinnati, OH (United States); Houk, T.C. [Lockheed Martin Energy Systems, Piketon, OH (United States)


    The overall goal of the program of activities is to demonstrate robust and cost-effective technologies for in situ remediation of DNAPL compounds in low permeability media (LPM), including adaptations and enhancements of conventional technologies to achieve improved performance for DNAPLs in LPM. The technologies sought should be potential for application at simple, small sites (e.g., gasoline underground storage tanks) as well as at complex, larger sites (e.g., DOE land treatment units). The technologies involved in the X-231A demonstration at Portsmouth Gaseous Diffusion Plant (PORTS) utilized subsurface manipulation of the LPM through soil fracturing with thermally enhanced mass recovery or horizontal barrier in place destruction. To enable field evaluation of these approaches, a set of four test cells was established at the X-231A land treatment unit at the DOE PORTS plant in August 1996 and a series of demonstration field activities occurred through December 1997. The principal objectives of the PORTS X-231A demonstration were to: determine and compare the operational features of hydraulic fractures as an enabling technology for steam and hot air enhanced soil vapor extraction and mass recovery, in situ interception and reductive destruction by zero valent iron, and in situ interception and oxidative destruction by potassium permanganate; determine the interaction of the delivered agents with the LPM matrix adjacent to the fracture and within the fractured zone and assess the beneficial modifications to the transport and/or reaction properties of the LPM deposit; and determine the remediation efficiency achieved by each of the technology strategies.

  20. A semi-analytical model for heat and mass transfer in geothermal reservoirs to estimate fracture surface-are-to-volume ratios and thermal breakthrough using thermally-decaying and diffusing tracers

    Energy Technology Data Exchange (ETDEWEB)

    Reimus, Paul W [Los Alamos National Laboratory


    A semi-analytical model was developed to conduct rapid scoping calculations of responses of thermally degrading and diffusing tracers in multi-well tracer tests in enhanced geothermal systems (EGS). The model is based on an existing Laplace transform inversion model for solute transport in dual-porosity media. The heat- and mass-transfer calculations are decoupled and conducted sequentially, taking advantage of the fact that heat transfer between fractures and the rock matrix is much more rapid than mass transfer and therefore mass transfer will effectively occur in a locally isothermal system (although the system will be nonisothermal along fracture flow pathways, which is accounted for by discretizing the flow pathways into multiple segments that have different temperature histories). The model takes advantage of the analogies between heat and mass transfer, solving the same governing equations with k{sub m}/({rho}C{sub p}){sub w} being substituted for {phi}D{sub m} in the equation for fracture transport and k{sub m}/({rho}C{sub p}){sub m} being subsituted for D{sub m} in the equation for matrix transport; where k = thermal conductivity (cal/cm-s-K), {rho} = density (g/cm{sup 3}), C{sub p} = heat capacity (at constant pressure) (cal/g-K), {phi} = matrix porosity, and D = tracer diffusion coefficient (cm{sup 2}/s), with the subscripts w and m referring to water and matrix, respectively. A significant advantage of the model is that it executes in a fraction of second on a single-CPU personal computer, making it very amenable for parameter estimation algorithms that involve repeated runs to find global minima. The combined thermal-mass transport model was used to evaluate the ability to estimate when thermal breakthrough would occur in a multi-well EGS configuration using thermally degrading tracers. Calculations were conducted to evaluate the range of values of Arrhenius parameters, A and E{sub {alpha}} (pre-exponential factor, 1/s, and activation energy, cal

  1. Fracture resistance of porcelain veneered zirconia crowns with exposed lingual zirconia for anterior teeth after thermal cycling: An in vitro study (United States)

    Amir Rad, Fatemeh A.; Succaria, Faysal G.; Morgano, Steven M.


    Statement of problem In some clinical conditions minimally invasive complete crown tooth preparations are indicated. This is especially true when gross removal of tooth structure would weaken the remaining tooth or violate the vitality of the dental pulp. Objective The purpose of this study was to investigate the influence of (1) exposed lingual zirconia with veneered zirconia crowns, and (2) reduced lingual thickness of monolithic lithium disilicate crowns on the fracture resistance of the crowns after cyclic loading. Metal-ceramic crowns with exposed lingual metal served as controls. Materials and methods Twenty-four maxillary central incisor crowns were fabricated in identical shape on metal testing dies in 3 groups: metal-ceramic crowns (MC, n = 8), veneered zirconia crowns (VZ, n = 8), and monolithic lithium disilicate crowns (MO, n = 8). A conservative preparation design with 0.75 mm lingual clearance was used for each crown system. All crowns were cemented to their corresponding crown preparations with self-adhesive resin cement (Multilink Automix). The crowns were subjected to 1000 cycles of thermal cycling, then cyclic loading of 111 N by means of a stainless steel ball, and 50,000 cycles of loading were applied for the fatigue test. Fatigue loading was followed by a continuously increasing compressive load, at a crosshead speed of 1 mm/min until failure. The compressive load (N) required to cause failure was recorded. Means were calculated and analyzed with one-way ANOVA and the Tukey HSD test (α = .05). Results There was a significant difference between MO vs. MC (P = .0001), MO vs. VZ (P = .0001), and VZ vs. MC (P = .012). Conclusions There was a significant difference in the mean fracture resistance of MC, VZ, and MO crowns in this in vitro study. The MC group recorded the highest mean fracture strength. PMID:26082571

  2. Fracture resistance of porcelain veneered zirconia crowns with exposed lingual zirconia for anterior teeth after thermal cycling: An in vitro study. (United States)

    Amir Rad, Fatemeh A; Succaria, Faysal G; Morgano, Steven M


    In some clinical conditions minimally invasive complete crown tooth preparations are indicated. This is especially true when gross removal of tooth structure would weaken the remaining tooth or violate the vitality of the dental pulp. The purpose of this study was to investigate the influence of (1) exposed lingual zirconia with veneered zirconia crowns, and (2) reduced lingual thickness of monolithic lithium disilicate crowns on the fracture resistance of the crowns after cyclic loading. Metal-ceramic crowns with exposed lingual metal served as controls. Twenty-four maxillary central incisor crowns were fabricated in identical shape on metal testing dies in 3 groups: metal-ceramic crowns (MC, n = 8), veneered zirconia crowns (VZ, n = 8), and monolithic lithium disilicate crowns (MO, n = 8). A conservative preparation design with 0.75 mm lingual clearance was used for each crown system. All crowns were cemented to their corresponding crown preparations with self-adhesive resin cement (Multilink Automix). The crowns were subjected to 1000 cycles of thermal cycling, then cyclic loading of 111 N by means of a stainless steel ball, and 50,000 cycles of loading were applied for the fatigue test. Fatigue loading was followed by a continuously increasing compressive load, at a crosshead speed of 1 mm/min until failure. The compressive load (N) required to cause failure was recorded. Means were calculated and analyzed with one-way ANOVA and the Tukey HSD test (α = .05). There was a significant difference between MO vs. MC (P = .0001), MO vs. VZ (P = .0001), and VZ vs. MC (P = .012). There was a significant difference in the mean fracture resistance of MC, VZ, and MO crowns in this in vitro study. The MC group recorded the highest mean fracture strength.

  3. Thermal effects on fluid flow and hydraulic fracturing from wellbores and cavities in low-permeability formations

    Energy Technology Data Exchange (ETDEWEB)

    Yarlong Wang [Petro-Geotech Inc., Calgary, AB (Canada); Papamichos, Euripides [IKU Petroleum Research, Trondheim (Norway)


    The coupled heat-fluid-stress problem of circular wellbore or spherical cavity subjected to a constant temperature change and a constant fluid flow rate is considered. Transient analytical solutions for temperature, pore pressure and stress are developed by coupling conductive heat transfer with Darcy fluid flow in a poroelastic medium. They are applicable to lower permeability porous media suitable for liquid-waste disposal and also simulating reservoir for enhanced oil recovery, where conduction dominates the heat transfer process. A full range of solutions is presented showing separately the effects of temperature and fluid flow on pore pressure and stress development. It is shown that injection of warm fluid can be used to restrict fracture development around wellbores and cavities and generally to optimise a fluid injection operation. Both the limitations of the solutions and the convective flow effect are addressed. (Author)

  4. Thermal fracturing of the well H-40, Los Humeros, Pue., geothermal field; Fracturamiento termico del pozo H-40 del campo geotermico de Los Humeros, Pue.

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly; Tovar Aguado, Rigoberto [Comision Federal de Electricidad (Mexico)]. E-mail:


    Well H-40 was drilled for production in 1997, but the well was not able to sustain flow. After it was monitored to assess its injection capacity, the well was changed to an injection well, but the well did not accept more than 5 tons of fluid per hour (t/h). The well was stimulated by thermal fracturing in three tests made in October 2005. As a result, the well can accept up to 110t/h and can be used as an injection well. [Spanish] El pozo H-40 se perforo con objetivos de produccion en 1997. Sin embargo, el pozo resulto incapaz de mantenerse fluyendo. Despues de un periodo de monitoreo se evaluo su capacidad de aceptacion para tratar de utilizarlo como pozo inyector, observandose que no aceptaba mas de 5 toneladas por hora (t/h) de fluido. Por lo tanto, se decidio estimularlo mediante fracturamiento termico con tres pruebas que se realizaron en octubre de 2005, lograndose que el pozo llegara a aceptar hasta 110 t/h, lo que permitira que el pozo pueda ser usado como inyector.

  5. Geothermal Ultrasonic Fracture Imager

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Doug [Baker-Hughes Oilfield Operation Inc., Houston, TX (United States); Leggett, Jim [Baker-Hughes Oilfield Operation Inc., Houston, TX (United States)


    The Geothermal Ultrasonic Fracture Imager project has a goal to develop a wireline ultrasonic imager that is capable of operating in temperatures up to 300°C (572°F) and depths up to 10 km (32,808 ft). This will address one of the critical needs in any EGS development of understanding the hydraulic flow paths in the reservoir. The ultrasonic imaging is well known in the oil and gas industry as one of the best methods for fracture evaluation; providing both high resolution and complete azimuthal coverage of the borehole. This enables fracture detection and characterization, both natural and induced, providing information as to their location, dip direction and dip magnitude. All of these factors are critical to fully understand the fracture system to enable the optimization of the thermal drainage through injectors and producers in a geothermal resource.

  6. fracture criterion

    Indian Academy of Sciences (India)

    Fracture in metallic glasses. What are the connections between nano- and micro- mechanisms and toughness? Metallic glasses are schizophrenic in the fracture sense. PDF Create! 5 Trial ...

  7. Shoulder Fractures (United States)

    ... arm bone), the scapula (shoulder blade) and the clavicle (collarbone) (Figure 1). The upper end of the humerus ... age. Most fractures in children occur in the clavicle bone. In adults, the most common fracture is ...

  8. Hand Fractures (United States)

    ... lead to arthritis down the road. In addition, fractures in children occasionally affect future growth of that bone. Figure 1: Examples of fractures in fingers Figure 2: Examples of plates, pins ...

  9. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios


    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed.......The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  10. Stress Fractures (United States)

    Stress fractures Overview Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of ...

  11. Hip fracture - discharge (United States)

    Inter-trochanteric fracture repair - discharge; Subtrochanteric fracture repair - discharge; Femoral neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - ...

  12. Acetabular Fracture

    Directory of Open Access Journals (Sweden)

    Chad Correa


    Full Text Available History of present illness: A 77-year-old female presented to her primary care physician (PCP with right hip pain after a mechanical fall. She did not lose consciousness or have any other traumatic injuries. She was unable to ambulate post-fall, so X-rays were ordered by her PCP. Her X-rays were concerning for a right acetabular fracture (see purple arrows, so the patient was referred to the emergency department where a computed tomography (CT scan was ordered. Significant findings: The non-contrast CT images show a minimally displaced comminuted fracture of the right acetabulum involving the acetabular roof, medial and anterior walls (red arrows, with associated obturator muscle hematoma (blue oval. Discussion: Acetabular fractures are quite rare. There are 37 pelvic fractures per 100,000 people in the United States annually, and only 10% of these involve the acetabulum. They occur more frequently in the elderly totaling an estimated 4,000 per year. High-energy trauma is the primary cause of acetabular fractures in younger individuals and these fractures are commonly associated with other fractures and pelvic ring disruptions. Fractures secondary to moderate or minimal trauma are increasingly of concern in patients of advanced age.1 Classification of acetabular fractures can be challenging. However, the approach can be simplified by remembering the three basic types of acetabular fractures (column, transverse, and wall and their corresponding radiologic views. First, column fractures should be evaluated with coronally oriented CT images. This type of fracture demonstrates a coronal fracture line running caudad to craniad, essentially breaking the acetabulum into two halves: a front half and a back half. Secondly, transverse fractures should be evaluated by sagittally oriented CT images. By definition, a transverse fracture separates the acetabulum into superior and inferior halves with the fracture line extending from anterior to posterior

  13. Laboratory Visualization Experiments of Temperature-induced Fractures Around a Borehole (Cryogenic Fracturing) in Shale and Analogue Rock Samples (United States)

    Kneafsey, T. J.; Nakagawa, S.; Wu, Y. S.; Mukhopadhyay, S.


    In tight shales, hydraulic fracturing is the dominant method for improving reservoir permeability. However, injecting water-based liquids can induce formation damage and disposal problems, thus other techniques are being sought. One alternative to hydraulic fracturing is producing fractures thermally, using low-temperature fluids (cryogens). The primary consequence of thermal stimulation is that shrinkage fractures are produced around the borehole wall. Recently, cryogenic stimulation produced some promising results when the cryogen (typically liquid nitrogen and cold nitrogen gas) could be brought to reservoir depth. Numerical modeling also showed possible significant increases in gas production from a shale reservoir after cryogenic stimulation. However, geometry and the dynamic behavior of these thermally induced fractures under different stress regimes and rock anisotropy and heterogeneity is not yet well understood.Currently, we are conducting a series of laboratory thermal fracturing experiments on Mancos Shale and transparent glass blocks, by injecting liquid nitrogen under atmospheric pressure into room temperature blocks under various anisotropic stress states. The glass blocks allow clear optical visualization of fracture development and final fracturing patterns. For the shale blocks, X-ray CT is used to image both pre-existing and induced fractures. Also, the effect of borehole orientation with respect to the bedding planes and aligned preexisting fractures is examined. Our initial experiment on a uniaxially compressed glass block showed fracturing behavior which was distinctly different from conventional hydraulic fracturing. In addition to tensile fractures in the maximum principal stress directions, the thermal contraction by the cryogen induced (1) chaotic, spalling fractures around the borehole wall, and (2) a series of disk-shaped annular fractures perpendicular to the borehole. When applied to a horizontal borehole, the propagation plane of the

  14. Hip Fractures. (United States)

    Ramponi, Denise R; Kaufmann, Judith; Drahnak, Gwendolen

    Hip fractures are associated with significant morbidity and mortality and a major health problem in the United States (). Eighty percent of hip fractures are experienced by 80-year-old women. Plain radiographs usually confirm the diagnosis, but if there is a high level of suspicion of an occult hip fracture, magnetic resonance imaging or bone scan is the next step to confirm the diagnosis. Areas of the hip bone have varied bone strength and blood supply, making the femoral neck one of the most vulnerable areas for fracture. A consultation to an orthopedic surgeon will determine surgical interventions.

  15. Hamate fractures. (United States)

    Sarabia Condés, J M; Ibañez Martínez, L; Sánchez Carrasco, M A; Carrillo Julia, F J; Salmerón Martínez, E L


    The purpose of this paper is to present our experience in the treatment of the fractures of the hamate and to make a review of the literature on this topic. We retrospectively reviewed 10 patients treated in our clinic between 2005-2012 suffering from fractures of the hamate. Six cases were fractures of the body and four were fractures of the hamate. Five cases were of associated injuries. Diagnostic delay ranged from 30 days to 2 years. Patient follow-up ranged from 1 to 10 years. Patient satisfaction was evaluated using the DASH questionnaire. Five patients with a fracture of the body underwent surgery, and one was treated conservatively. Two patients with fracture of the hook of the hamate were treated with immobilization, and two more patients had the fragment removed. The grip strength and the digital clip were reduced in 2 cases. Flexion and extension of the wrist was limited in 3 cases. The mobility of the fingers was normal in all the cases, except in one. The results obtained from the DASH questionnaire were normal in all the cases, except in one case of fracture of the hamate, and in two cases of fracture of the body. The surgical treatment should reduce the dislocation and stabilize the injuries with osteosynthesis. The fractures of the hamate are usually diagnosed late, and the most recommended treatment is removal of the fragment, although it cannot be deduced from this study. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

  16. Colles Fracture


    Sánchez León, Belisario; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú


    Our expertise is the study of more than 2,000 cases of Colles' fractures. Colles name should in this case to synthesize the type of fractures of the lower end of the radius. There have been various proposed classifications according to the different fracture lines can be demonstrated radiologically in the region of the wrist. We believe that these ratings should only be retained if the concept of the articular fracture or not in the classical sense, since it has great value in the functional ...

  17. Estimation of thermal fracture limits in quasi-continuous-wave end-pumped lasers through a time-dependent analytical model

    NARCIS (Netherlands)

    Bernhardi, Edward; Martijn de Sterke, C.; Forbes, A.; Bollig, C.; Esser, M.J.D.


    A time–dependent analytical thermal model of the temperature and the corresponding induced thermal stresses on the pump face of quasi–continuous wave (qcw) end-pumped laser rods is derived. We apply the model to qcw diode–end–pumped rods and show the maximum peak pump power that can be utilized

  18. Cold-Cracking Assessment in AA7050 Billets during Direct-Chill Casting by Thermomechanical Simulation of Residual Thermal Stresses and Application of Fracture Mechanics

    NARCIS (Netherlands)

    Lalpoor, M.; Eskin, D.G.; Katgerman, L.


    Thermally induced strains and stresses developed during direct-chill (DC) semicontinuous casting of high strength aluminum alloys can result in formation of micro-cracks in different locations of the billet. Rapid propagation of such micro-cracks in tensile thermal stress fields can lead to

  19. Treatment of tooth fracture by medium energy CO2 laser and DP-bioactive glass paste: thermal behavior and phase transformation of human tooth enamel and dentin after irradiation by CO2 laser. (United States)

    Lin, C P; Lee, B S; Kok, S H; Lan, W H; Tseng, Y C; Lin, F H


    Acute trauma or trauma associated with occlusal disharmony can produce tooth crack or fracture. Although several methods are proposed to treat the defect, however, the prognosis is generally poor. If the fusion of a tooth fracture by laser is possible it will offer an alternative to extraction or at least serve as an adjunctive treatment in the reconstruction. The responses of soft tissues to lasers of different wavelengths are fairly well known, but the reactions of hard tissues are still to be understood. The purpose of this research was to study the feasibility of using a medium energy continuous-wave CO(2) laser and a low melting-point bioactive glass to fuse or bridge tooth fractures. The present report is focused on the first part of the research, the analysis of changes in laser-irradiated human tooth enamel/dentin by means of X-ray diffractometer (XRD), Fourier-transforming infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). After CO(2) laser irradiation, there were no marked changes in the X-ray diffraction pattern of the enamel when compared to that before laser treatment. However, a small peak belonging to alpha-TCP appeared at the position of 2theta=30.78 degrees C. After being treated with CO(2) laser, the dentin showed much sharper peaks on the diffraction patterns because of grain growth and better crystallinity. alpha-TCP and beta-TCP were identified after laser treatment. In the FTIR analysis, an HPO(4)(-2) absorption band was noted before laser treatment disappeared after the irradiation. No significant change in the absorption band of HPO(4)(-2) was found on the FTIR curves of enamel after laser treatment. The results of DTA/TGA indicated that loss of water and organic materials occurred in both enamel and dentin after laser treatment. Under SEM, melting and resolidification occurred in both enamel and dentin by medium energy of CO(2) laser. This implies that

  20. Greenstick Fractures (United States)

    ... small, "green" branch on a tree. Most greenstick fractures occur in children younger than 10 years of age. This type ... mistaken for sprains or bruises. More-severe greenstick fractures may cause an obvious ... your doctor if your child has persistent pain in an injured limb. Seek ...

  1. Fracture resistance of porcelain veneered zirconia crowns with exposed lingual zirconia for anterior teeth after thermal cycling: An in vitro study


    Amir Rad, Fatemeh A.; Succaria, Faysal G.; Morgano, Steven M.


    Statement of problem: In some clinical conditions minimally invasive complete crown tooth preparations are indicated. This is especially true when gross removal of tooth structure would weaken the remaining tooth or violate the vitality of the dental pulp. Objective: The purpose of this study was to investigate the influence of (1) exposed lingual zirconia with veneered zirconia crowns, and (2) reduced lingual thickness of monolithic lithium disilicate crowns on the fracture resistance of ...

  2. Fracture Mechanics

    CERN Document Server

    Zehnder, Alan T


    Fracture mechanics is a vast and growing field. This book develops the basic elements needed for both fracture research and engineering practice. The emphasis is on continuum mechanics models for energy flows and crack-tip stress- and deformation fields in elastic and elastic-plastic materials. In addition to a brief discussion of computational fracture methods, the text includes practical sections on fracture criteria, fracture toughness testing, and methods for measuring stress intensity factors and energy release rates. Class-tested at Cornell, this book is designed for students, researchers and practitioners interested in understanding and contributing to a diverse and vital field of knowledge. Alan Zehnder joined the faculty at Cornell University in 1988. Since then he has served in a number of leadership roles including Chair of the Department of Theoretical and Applied Mechanics, and Director of the Sibley School of Mechanical and Aerospace Engineering.  He teaches applied mechanics and his research t...

  3. Ankle fracture - aftercare (United States)

    Malleolar fracture; Tri-malleolar; Bi-malleolar; Distal tibia fracture; Distal fibula fracture; Malleolus fracture ... Some ankle fractures may require surgery when: The ends of the bone are out of line with each other (displaced). The ...

  4. Thermal shock fracture mechanics analysis of a semi-infinite medium based on the dual-phase-lag heat conduction model (United States)

    Wang, B.; Li, J. E.; Yang, C.


    The generalized lagging behaviour in solids is very important in understanding heat conduction in small-scale and high-rate heating. In this paper, an edge crack in a semi-infinite medium subjected to a heat shock on its surface is studied under the framework of the dual-phase-lag (DPL) heat conduction model. The transient thermal stress in the medium without crack is obtained first. This stress is used as the crack surface traction with an opposite sign to formulate the crack problem. Numerical results of thermal stress intensity factor are obtained as the functions of crack length and thermal shock time. Crack propagation predictions are conducted and results based on the DPL model and those based on the classical Fourier heat conduction model are compared. The thermal shock strength that the medium can sustain without catastrophic failure is established according to the maximum local stress criterion and the stress intensity factor criterion. PMID:25663805

  5. The Influence of Temperature on Mode I Fracture Toughness and Fracture Characteristics of Sandstone (United States)

    Feng, Gan; Kang, Yong; Meng, Tao; Hu, Yao-qing; Li, Xiao-hong


    This study investigated the influence of temperature on the mode I fracture toughness of sandstone using semicircular bend specimens. Fracture characteristics were studied using scanning electron microscopy and other means. The results showed that temperature influenced fracturing in three stages along a temperature gradient. In the low-temperature stage (20-100 °C), fracture toughness increases slowly, with a total increase of approximately 11%. At the medium-temperature stage (100-500 °C), fracture toughness decreases slowly, at a rate of approximately 18%. During the high-temperature stage (500-800 °C), fracture toughness was reduced by approximately 44%. The mode I fracture toughness has a clear temperature threshold (500-600 °C). Below this threshold, the fracture toughness decreases slowly. When the temperature threshold is reached, the fracture toughness decreases sharply. The sharp decrease is mainly caused by the creation of a fragmentation structure. The sandstone experiences more transgranular fracture mechanics in the low-temperature stage compared to the high-temperature stage. Above 100 °C, the mechanisms include transgranular fracturing, intergranular fracturing, thermal cracking, and mutual coupling fracturing. When the temperature exceeds 500 °C, several different fragmentation structures are seen. This research study provides significant data to evaluate fracture characteristics and rock safety and stability after heat treatment.

  6. Fracture fixation. (United States)

    Taljanovic, Mihra S; Jones, Marci D; Ruth, John T; Benjamin, James B; Sheppard, Joseph E; Hunter, Tim B


    The basic goal of fracture fixation is to stabilize the fractured bone, to enable fast healing of the injured bone, and to return early mobility and full function of the injured extremity. Fractures can be treated conservatively or with external and internal fixation. Conservative fracture treatment consists of closed reduction to restore the bone alignment. Subsequent stabilization is then achieved with traction or external splinting by slings, splints, or casts. Braces are used to limit range of motion of a joint. External fixators provide fracture fixation based on the principle of splinting. There are three basic types of external fixators: standard uniplanar fixator, ring fixator, and hybrid fixator. The numerous devices used for internal fixation are roughly divided into a few major categories: wires, pins and screws, plates, and intramedullary nails or rods. Staples and clamps are also used occasionally for osteotomy or fracture fixation. Autogenous bone grafts, allografts, and bone graft substitutes are frequently used for the treatment of bone defects of various causes. For infected fractures as well as for treatment of bone infections, antibiotic beads are frequently used. Copyright RSNA, 2003

  7. Fracture mechanics

    CERN Document Server

    Perez, Nestor


    The second edition of this textbook includes a refined presentation of concepts in each chapter, additional examples; new problems and sections, such as conformal mapping and mechanical behavior of wood; while retaining all the features of the original book. The material included in this book is based upon the development of analytical and numerical procedures pertinent to particular fields of linear elastic fracture mechanics (LEFM) and plastic fracture mechanics (PFM), including mixed-mode-loading interaction. The mathematical approach undertaken herein is coupled with a brief review of several fracture theories available in cited references, along with many color images and figures. Dynamic fracture mechanics is included through the field of fatigue and Charpy impact testing. Explains computational and engineering approaches for solving crack-related problems using straightforward mathematics that facilitate comprehension of the physical meaning of crack growth processes; Expands computational understandin...

  8. DECOVALEX III III/BENCHPAR PROJECTS. Approaches to Upscaling Thermal-Hydro-Mechanical Processes in a Fractured Rock. Mass and its Significance for Large-Scale Repository Performance Assessment. Summary of Findings. Report of BMT2/WP3

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Johan (comp.) [JA Streamflow AB, Aelvsjoe (Sweden); Staub, Isabelle (comp.) [Golder Associates AB, Stockholm (Sweden); Knight, Les (comp.) [Nirex UK Ltd, Oxon (United Kingdom)


    The Benchmark Test 2 of DECOVALEX III and Work Package 3 of BENCHPAR concerns the upscaling Thermal (T), Hydrological (H) and Mechanical (M) processes in a fractured rock mass and its significance for large-scale repository performance assessment. The work is primarily concerned with the extent to which various thermo-hydro-mechanical couplings in a fractured rock mass adjacent to a repository are significant in terms of solute transport typically calculated in large-scale repository performance assessments. Since the presence of even quite small fractures may control the hydraulic, mechanical and coupled hydromechanical behaviour of the rock mass, a key of the work has been to explore the extent to which these can be upscaled and represented by 'equivalent' continuum properties appropriate PA calculations. From these general aims the BMT was set-up as a numerical study of a large scale reference problem. Analysing this reference problem should: help explore how different means of simplifying the geometrical detail of a site, with its implications on model parameters, ('upscaling') impacts model predictions of relevance to repository performance, explore to what extent the THM-coupling needs to be considered in relation to PA-measures, compare the uncertainties in upscaling (both to uncertainty on how to upscale or uncertainty that arises due to the upscaling processes) and consideration of THM couplings with the inherent uncertainty and spatial variability of the site specific data. Furthermore, it has been an essential component of the work that individual teams not only produce numerical results but are forced to make their own judgements and to provide the proper justification for their conclusions based on their analysis. It should also be understood that conclusions drawn will partly be specific to the problem analysed, in particular as it mainly concerns a 2D application. This means that specific conclusions may have limited applicability

  9. Supracondylar Fracture

    Directory of Open Access Journals (Sweden)

    Jessica Andrusaitis


    Full Text Available History of present illness: A 15-year-old male presented to the emergency department with right elbow pain after falling off a skateboard. The patient denied a decrease in strength or sensation but did endorse paresthesias to his hand. On exam, the patient had an obvious deformity of his right elbow with tenderness to palpation and decreased range of motion at the elbow. Sensation, motor function, and pulses were intact. Radiographic imaging was obtained. Significant findings: The pre-reduction films show a type III supracondylar fracture. There is complete displacement of the distal humerus anteriorly. Specific findings for supracondylar fracture include: a posterior fat pad (red arrow and a displaced anterior humeral line (yellow line.1 When no fracture is present, the anterior humeral line should intersect the middle third of the capitellum; in this X-ray, it does not intersect the capitellum at all. This X-ray demonstrates a normal radiocapitellar line (blue line that intersects the capitellum. The presence of a narrow anterior fat pad aka “sail sign” can be normal. Discussion: Supracondylar fractures of the humerus occur at the distal portion of the humerus without involving the growth plate.2 This is the second most common fracture in children overall. In children, it is the most common fracture of the elbow.3 This injury has a high risk of neurovascular compromise, such as compartment syndrome or ischemic contracture, and thus the clinician must perform immediate and frequent neurovascular assessments focusing on the distributions of the brachial artery in addition to the median, ulnar, and radial nerves.4 Hyperextension injuries that typically occur following a fall onto an outstretched arm are responsible for 95% of supracondylar fractures.1 A type I supracondylar fracture is non-displaced and can be treated with immobilization through a posterior splint and sling5 with close follow-up, type II is angulated but with an intact

  10. Hydraulic fracturing

    Energy Technology Data Exchange (ETDEWEB)

    Clampitt, R.L.


    A method of fracturing a subterranean porous formation penetrated by a well bore consists of injecting down the well and into the formation, at a pressure sufficient to fracture the formation, a fracturing fluid comprising an aqueous gel. This gel is composed of water to which there has been added: a water-thickening amount of a water-dispersible polymer selected from the group consisting of polyacrylamides and polymethacrylamides; crosslinked polyacrylamides and crosslinked polyacrylamides; polyacrylic acid and polymethacrylic acid; polyacrylates; polymers of N-substituted acrylamides; copolymers of acrylamide with another ethylenically unsaturated monomer copolymerizable therewith; mixtures of the polymers; a water-soluble compound of a polyvalent metal which is capable of gelling the water when the valence of the metal is reduced to a lower valence state; and a water-soluble reducing agent. (31 claims)

  11. [Stress fractures]. (United States)

    Uhl, M


    Bone stress injuries are due to repetitive mechanical overuse of the skeleton and occur as a result of microscopic lesions sustained when bone is subjected to repeated submaximal stress. Over time accumulation of such injuries can lead to bone failure and fractures. Stress-related bone injuries are relatively common among otherwise healthy persons who have recently started new or intensified forms of physical training activities. Stress injuries lead to typical findings on radiography, bone scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI) and need to be discriminated from other conditions, in particular infections and neoplasms. Stress fractures must be differentiated from insufficiency fractures that occur in bones with reduced mechanical resistance or disturbed structure.

  12. Fracture Blisters

    Directory of Open Access Journals (Sweden)

    Uebbing, Claire M


    Full Text Available Fracture blisters are a relatively uncommon complication of fractures in locations of the body, such as the ankle, wrist elbow and foot, where skin adheres tightly to bone with little subcutaneous fat cushioning. The blister that results resembles that of a second degree burn.These blisters significantly alter treatment, making it difficult to splint or cast and often overlying ideal surgical incision sites. Review of the literature reveals no consensus on management; however, most authors agree on early treatment prior to blister formation or delay until blister resolution before attempting surgical correction or stabilization. [West J Emerg Med. 2011;12(1;131-133.

  13. Thermally induced delamination of multilayers

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Sarraute, S.; Jørgensen, O.


    Steady-state delamination of multilayered structures, caused by stresses arising during processing due to thermal expansion mismatch, is analyzed by a fracture mechanics model based on laminate theory. It is found that inserting just a few interlayers with intermediate thermal expansion coefficie......Steady-state delamination of multilayered structures, caused by stresses arising during processing due to thermal expansion mismatch, is analyzed by a fracture mechanics model based on laminate theory. It is found that inserting just a few interlayers with intermediate thermal expansion...

  14. Hydraulic fracturing in granite under geothermal conditions (United States)

    Solberg, P.; Lockner, D.; Byerlee, J.D.


    The experimental hydraulic fracturing of granite under geothermal conditions produces tensile fracture at rapid fluid injection rates and shear fracture at slow injection rates and elevated differential stress levels. A sudden burst of acoustic emission activity accompanies tensile fracture formation whereas the acoustic emission rate increases exponentially prior to shear fracture. Temperature does not significantly affect the failure mechanism, and the experimental results have not demonstrated the occurrence of thermal fracturing. A critical result of these experiments is that fluid injection at intermediate rates and elevated differential stress levels increases permeability by more than an order of magnitude without producing macroscopic fractures, and low-level acoustic emission activity occurs simultaneously near the borehole and propagates outward into the specimen with time. Permeability measurements conducted at atmospheric pressure both before and after these experiments show that increased permeability is produced by permanent structural changes in the rock. Although results of this study have not demonstrated the occurrence of thermal fracturing, they suggest that fluid injection at certain rates in situ may markedly increase local permeability. This could prove critical to increasing the efficiency of heat exchange for geothermal energy extraction from hot dry rock. ?? 1980.

  15. Evaluation on the Feasibility of Using Ultrasonic Testing of Reactor Pressure Vessel Welds for Assessing Flaw Density/Distribution per 10 CFR 50.61a, Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Edmund J.; Anderson, Michael T.


    This technical letter report provides the status of an assessment undertaken by PNNL at the request of the NRC to verify the capability of periodic ASME-required volumetric examinations of reactor vessels to characterize the density and distribution of flaws of interest for applying §50.61a on a plant-by-plant basis. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), "Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events," establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. Recently, the NRC completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed and promulgated an alternate PTS rule, §50.61a, that can be implemented by PWR licensees. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants.

  16. Bimalleolar ankle fracture with proximal fibular fracture

    NARCIS (Netherlands)

    Colenbrander, R. J.; Struijs, P. A. A.; Ultee, J. M.


    A 56-year-old female patient suffered a bimalleolar ankle fracture with an additional proximal fibular fracture. This is an unusual fracture type, seldom reported in literature. It was operatively treated by open reduction and internal fixation of the lateral malleolar fracture. The proximal fibular

  17. Correlation of Electrical Resistance to CMC Stress-Strain and Fracture Behavior Under High Heat-Flux Thermal and Stress Gradients (United States)

    Appleby, Matthew; Morscher, Gregory; Zhu, Dongming


    Because SiCSiC ceramic matrix composites (CMCs) are under consideration for use as turbine engine hot-section components in extreme environments, it becomes necessary to investigate their performance and damage morphologies under complex loading and environmental conditions. Monitoring of electrical resistance (ER) has been shown as an effective tool for detecting damage accumulation of woven melt-infiltrated SiCSiC CMCs. However, ER change under complicated thermo-mechanical loading is not well understood. In this study a systematic approach is taken to determine the capabilities of ER as a relevant non-destructive evaluation technique for high heat-flux testing, including thermal gradients and localized stress concentrations. Room temperature and high temperature, laser-based tensile tests were conducted in which stress-dependent damage locations were determined using modal acoustic emission (AE) monitoring and compared to full-field strain mapping using digital image correlation (DIC). This information is then compared with the results of in-situ ER monitoring, post-test ER inspection and fractography in order to correlate ER response to convoluted loading conditions and damage evolution.

  18. Distal radius triplane fracture. (United States)

    Parkar, A A H; Marya, S; Auplish, S


    A triplane fracture is so named because of the three planes traversed by the fracture line. These are physeal fractures that result from injury during the final phase of maturation and cessation of growth. This fracture pattern typically involves the distal tibia. We present a rare case of a triplane fracture involving the distal radius.

  19. An analytical thermohydraulic model for discretely fractured geothermal reservoirs (United States)

    Fox, Don B.; Koch, Donald L.; Tester, Jefferson W.


    In discretely fractured reservoirs such as those found in Enhanced/Engineered Geothermal Systems (EGS), knowledge of the fracture network is important in understanding the thermal hydraulics, i.e., how the fluid flows and the resulting temporal evolution of the subsurface temperature. The purpose of this study was to develop an analytical model of the fluid flow and heat transport in a discretely fractured network that can be used for a wide range of modeling applications and serve as an alternative analysis tool to more computationally intensive numerical codes. Given the connectivity and structure of a fracture network, the flow in the system was solved using a linear system of algebraic equations for the pressure at the nodes of the network. With the flow determined, the temperature in the fracture was solved by coupling convective heat transport in the fracture with one-dimensional heat conduction perpendicular to the fracture, employing the Green's function derived solution for a single discrete fracture. The predicted temperatures along the fracture surfaces from the analytical solution were compared to numerical simulations using the TOUGH2 reservoir code. Through two case studies, we showed the capabilities of the analytical model and explored the effect of uncertainty in the fracture apertures and network structure on thermal performance. While both sources of uncertainty independently produce large variations in production temperature, uncertainty in the network structure, whenever present, had a predominant influence on thermal performance.

  20. Hand fracture - aftercare (United States)

    ... this page: // Hand fracture - aftercare To use the sharing features on ... need to be repaired with surgery. Types of Hand Fractures Your fracture may be in one of ...

  1. Fractured porous media

    CERN Document Server

    Adler, Pierre M; Mourzenko, Valeri V


    This monograph on fractures, fracture networks, and fractured porous media provides a systematic treatment of their geometrical and transport properties for students and professionals in geophysics, materials science, and Earth sciences.

  2. A three-dimensional coupled thermo-hydro-mechanical model for deformable fractured geothermal systems

    DEFF Research Database (Denmark)

    Salimzadeh, Saeed; Paluszny, Adriana; Nick, Hamidreza M.


    A fully coupled thermal-hydraulic-mechanical (THM) finite element model is presented for fractured geothermal reservoirs. Fractures are modelled as surface discontinuities within a three-dimensional matrix. Non-isothermal flow through the rock matrix and fractures are defined and coupled to a mec......A fully coupled thermal-hydraulic-mechanical (THM) finite element model is presented for fractured geothermal reservoirs. Fractures are modelled as surface discontinuities within a three-dimensional matrix. Non-isothermal flow through the rock matrix and fractures are defined and coupled....... The model has been validated against several analytical solutions, and applied to study the effects of the deformable fractures on the injection of cold water in fractured geothermal systems. Results show that the creation of flow channelling due to the thermal volumetric contraction of the rock matrix...

  3. Acetabular Fracture


    Correa, Chad; Lahham, Sari


    History of present illness: A 77-year-old female presented to her primary care physician (PCP) with right hip pain after a mechanical fall. She did not lose consciousness or have any other traumatic injuries. She was unable to ambulate post-fall, so X-rays were ordered by her PCP. Her X-rays were concerning for a right acetabular fracture (see purple arrows), so the patient was referred to the emergency department where a computed tomography (CT) scan was ordered. Significant findings:...

  4. Galeazzi Fracture


    Reid Honda


    History of present illness: A 19-year-old male presented to the ED with right forearm pain after being struck in the forearm by a baseball. The patient then threw the ball and felt a sharp “pop” in his arm. The patient complained of sharp pain, worse with movement. Upon examination, the patient was neurovascularly intact. Significant findings: The X-ray showed an acute comminuted fracture of the distal diaphysis of the radius with disruption of the distal radioulnar joint, consisten...


    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi


    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  6. Fractures in multiple sclerosis

    DEFF Research Database (Denmark)

    Stenager, E; Jensen, K


    In a cross-sectional study of 299 MS patients 22 have had fractures and of these 17 after onset of MS. The fractures most frequently involved the femoral neck and trochanter (41%). Three patients had had more than one fracture. Only 1 patient had osteoporosis. The percentage of fractures increase...

  7. Oblique Axis Body Fracture

    DEFF Research Database (Denmark)

    Takai, Hirokazu; Konstantinidis, Lukas; Schmal, Hagen


    Anderson type III fractures with a characteristic fracture pattern that we refer to as "oblique type axis body fracture." Results. The female patients aged 90 and 72 years, respectively, were both diagnosed with minimally displaced Anderson type III fractures. Both fractures had a characteristic "oblique...... was uneventful. Conclusions. Oblique type axis body fractures resemble a highly unstable subtype of Anderson type III fractures with the potential of severe secondary deformity following conservative treatment, irrespective of initial grade of displacement. The authors therefore warrant a high index of suspicion...

  8. Assessment of fracture risk

    Energy Technology Data Exchange (ETDEWEB)

    Kanis, John A. [WHO Collaborating Centre for Metabolic Bone Diseases, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX (United Kingdom)], E-mail:; Johansson, Helena; Oden, Anders [WHO Collaborating Centre for Metabolic Bone Diseases, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX (United Kingdom); McCloskey, Eugene V. [WHO Collaborating Centre for Metabolic Bone Diseases, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX (United Kingdom); Osteoporosis Centre, Northern General Hospital, Sheffield (United Kingdom)


    Fractures are a common complication of osteoporosis. Although osteoporosis is defined by bone mineral density at the femoral neck, other sites and validated techniques can be used for fracture prediction. Several clinical risk factors contribute to fracture risk independently of BMD. These include age, prior fragility fracture, smoking, excess alcohol, family history of hip fracture, rheumatoid arthritis and the use of oral glucocorticoids. These risk factors in conjunction with BMD can be integrated to provide estimates of fracture probability using the FRAX tool. Fracture probability rather than BMD alone can be used to fashion strategies for the assessment and treatment of osteoporosis.

  9. Thermal front propagation in variable aperture fracture–matrix system

    Indian Academy of Sciences (India)

    the cold water and hot fractured rock to access the feasibility of geothermal energy production. Propagation of thermal fronts in a single phase fractured porous media was first studied by. Lauwerier (1955). Lauwerier developed an analytical solution for injection of hot water into oil bearing fractured rocks. Gringarten & Sauty ...

  10. [Arthroscopic fracture management in proximal humeral fractures]. (United States)

    Lill, H; Katthagen, C; Jensen, G; Voigt, C


    Arthroscopy has become increasingly more established in the treatment of proximal humeral fractures. In addition to the known advantages of minimally invasive surgery fracture and implant positioning can be optimized and controlled arthroscopically and relevant intra-articular concomitant pathologies (e.g. biceps tendon complex and rotator cuff) can be diagnosed and treated. Arthroscopic techniques have proven to be advantageous in the treatment of various entities of greater tuberosity fractures, lesser tuberosity fractures (suture bridging technique) and subcapital humeral fractures (arthroscopic nailing). This article presents an overview on innovative arthroscopic modalities for treating proximal humeral fractures, describes the surgical techniques and the advantages compared to open procedures as well as initial clinical results.

  11. Pediatric Phalanx Fractures. (United States)

    Abzug, Joshua M; Dua, Karan; Sesko Bauer, Andrea; Cornwall, Roger; Wyrick, Theresa O


    Phalangeal fractures are the most common type of hand fracture that occurs in the pediatric population and account for the second highest number of emergency department visits in the United States for fractures. The incidence of phalangeal fractures is the highest in children aged 10 to 14 years, which coincides with the time that most children begin playing contact sports. Younger children are more likely to sustain a phalangeal fracture in the home setting as a result of crush and laceration injuries. Salter-Harris type II fractures of the proximal phalanx are the most common type of finger fracture. An unmineralized physis is biomechanically weaker compared with the surrounding ligamentous structures and mature bone, which make fractures about the physis likely. A thorough physical examination is necessary to assess the digital cascade for signs of rotational deformity and/or coronal malalignment. Plain radiographs of the hand and digits are sufficient to confirm a diagnosis of a phalangeal fracture. The management of phalangeal fractures is based on the initial severity of the injury and depends on the success of closed reduction techniques. Nondisplaced phalanx fractures are managed with splint immobilization. Stable, reduced phalanx fractures are immobilized but require close monitoring to ensure maintenance of fracture reduction. Unstable, displaced phalanx fractures require surgical management, preferably via closed reduction and percutaneous pinning.

  12. Thermal front propagation in variable aperture fracture–matrix ...

    Indian Academy of Sciences (India)

    Keywords. Thermal front; variable aperture; rock-matrix; geothermal reservoir; numerical model, liquid dominated. Abstract. A numerical study on the effect of complex fracture aperture geometry on propagation of thermal front in a coupled single fracture-matrix system has been carried out. Sinusoidal and logarithmic ...

  13. Permeability of displaced fractures (United States)

    Kluge, Christian; Milsch, Harald; Blöcher, Guido


    Flow along fractures or in fissured systems becomes increasingly important in the context of Enhanced Geothermal Systems (EGS), shale gas recovery or nuclear waste deposit. Commonly, the permeability of fractures is approximated using the Hagen-Poiseuille solution of Navier Stokes equation. Furthermore, the flow in fractures is assumed to be laminar flow between two parallel plates and the cubic law for calculating the velocity field is applied. It is a well-known fact, that fracture flow is strongly influenced by the fracture surface roughness and the shear displacement along the fracture plane. Therefore, a numerical approach was developed which calculates the flow pattern within a fracture-matrix system. The flow in the fracture is described by a free fluid flow and the flow in the matrix is assumed to be laminar and therefore validates Darcy's law. The presented approach can be applied for artificially generated fractures or real fractures measured by surface scanning. Artificial fracture surfaces are generated using the power spectral density of the surface height random process with a spectral exponent to define roughness. For calculating the permeability of such fracture-matrix systems the mean fracture aperture, the shear displacement and the surface roughness are considered by use of a 3D numerical simulator. By use of this approach correlation between shear displacement and mean aperture, shear displacement and permeability, as well as surface roughness and permeability can be obtained. Furthermore, the intrinsic measured permeability presents a combination of matrix and fracture permeability. The presented approach allows the separation and quantification of the absolute magnitudes of the matrix and the fracture permeability and the permeability of displaced fractures can be calculated. The numerical approach which is a 3D numerical simulation of the fracture-matrix system can be applied for artificial as well as real systems.

  14. Thermally stable diamond brazing (United States)

    Radtke, Robert P [Kingwood, TX


    A cutting element and a method for forming a cutting element is described and shown. The cutting element includes a substrate, a TSP diamond layer, a metal interlayer between the substrate and the diamond layer, and a braze joint securing the diamond layer to the substrate. The thickness of the metal interlayer is determined according to a formula. The formula takes into account the thickness and modulus of elasticity of the metal interlayer and the thickness of the TSP diamond. This prevents the use of a too thin or too thick metal interlayer. A metal interlayer that is too thin is not capable of absorbing enough energy to prevent the TSP diamond from fracturing. A metal interlayer that is too thick may allow the TSP diamond to fracture by reason of bending stress. A coating may be provided between the TSP diamond layer and the metal interlayer. This coating serves as a thermal barrier and to control residual thermal stress.

  15. DECOVALEX III/BENCHPAR PROJECTS. Evaluation of the Impact of Thermal-Hydro-Mechanical Couplings in Bentonite and Near-Field Rock Barriers on a Nuclear Waste Repository in a Sparsely Fractured Hard Rock. Report of BMT1C/WP2

    Energy Technology Data Exchange (ETDEWEB)

    Jing, L. [Royal Inst. of Technology, Stockholm (Sweden). Engineering Geology; Nguyen, T.S. [Canadian Nuclear Safety Commission, Ottawa, ON (Canada)] (eds.)


    This report presents the works performed for the third, also the last, phase (BMT1C) of BMT1 of the DECOVALEX III project for the period of 1999-2002. The works of BMT1 is divided into three phases: BMT1A, BMT1B and BMT1C. The BMT1A concerns with calibration of the computer codes with a reference Thermal (T), Hydrological (H) and Mechanical (M) experiment at Kamaishi Mine, Japan. The objective is to validate the numerical approaches, computer codes and material models, so that the teams simulating tools are at a comparable level of maturity and sophistication. The BMT1B uses the calibrated codes to perform scoping calculations, considering varying degrees of THM coupling and varying permeability values of the surrounding rock for a reference generic repository design without fractures. The aim is to identify the coupling mechanisms of importance for construction, performance and safety of the repository. BMT1C concerns with scoping calculations with different coupling combinations for the case where a horizontal fracture intersects the deposition hole and a vertical fracture zone divides two adjacent deposition tunnel/hole system. A hydrostatic condition is applied along the vertical fracture as a hydraulic boundary condition. In addition, the SKI/KTH team performed an additional calculation case of a highly fractured rock mass with two orthogonal sets of fractures with a spacing of 0.5 m. The chosen measures for evaluating the long term safety and performance of the repository are the maximal temperature created by the thermal loading from the emplaced wastes, the time for resaturation of the buffer, the maximal swelling stress developed in the buffer, the structural integrity of the rock mass and the permeability evolution in the rock mass. The analyses fro BMT1C were conducted by four research teams: SKI/KTH (Sweden), CNSC (Canada), IRSN/CEA(France) and JNC (Japan), using FEM approach with different computer codes. From the results, it is clear that the

  16. Infant skull fracture (image) (United States)

    Skull fractures may occur with head injuries. Although the skull is both tough and resilient and provides excellent protection ... a severe impact or blow can result in fracture of the skull and may be accompanied by ...

  17. Nasal fracture (image) (United States)

    A nasal fracture is a break in the bone over the ridge of the nose. It usually results from a blunt ... and is one of the most common facial fracture. Symptoms of a broken nose include pain, blood ...

  18. Growth Plate Fractures (United States)

    .org Growth Plate Fractures Page ( 1 ) The bones of children and adults share many of the same risks for ... also subject to a unique injury called a growth plate fracture. Growth plates are areas of cartilage ...

  19. Bone fracture repair - slideshow (United States)

    ... page: // Bone fracture repair - series—Indications To use the sharing features ... Go to slide 4 out of 4 Overview Fractures of the bones are classified in a number ...

  20. Femur fracture repair - discharge (United States)

    ... page: // Femur fracture repair - discharge To use the sharing features on this page, please enable JavaScript. You had a fracture (break) in the femur in your leg. It ...

  1. Rib fracture - aftercare (United States)

    ... page: // Rib fracture - aftercare To use the sharing features on this page, please enable JavaScript. A rib fracture is a crack or break in one or ...

  2. Nasal fracture - aftercare (United States)

    ... page: // Nasal fracture - aftercare To use the sharing features on this ... that gives your nose its shape. A nasal fracture occurs when the bony part of your nose ...

  3. Hip fracture surgery (United States)

    ... neck fracture repair; Trochanteric fracture repair; Hip pinning surgery; Osteoarthritis - hip ... You may receive general anesthesia for this surgery. This means you ... spinal anesthesia . With this kind of anesthesia, medicine is ...

  4. Metatarsal stress fractures - aftercare (United States)

    ... page: // Metatarsal stress fractures - aftercare To use the sharing features on ... that connect your ankle to your toes. A stress fracture is a break in the bone that ...

  5. Everted skull fracture. (United States)

    Balasubramaniam, Srikant; Tyagi, Devendra K; Savant, Hemant V


    Skull bone fractures are common in trauma. They are usually linear undisplaced or depressed; however, a distinct possibility of elevated fracture remains. We describe an entity of everted fracture skull in which the fracture segment is totally everted. The nature of trauma, management, and complications of this unique case are discussed. A 21-year-old woman involved in a railway accident presented to us with a primary dressing on her wound. Investigations revealed an everted fracture skull. She underwent surgery with good results. We would like to add everted fracture skull to the nomenclature describing skull fractures in addition to elevated compound fracture skull as a new entity. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Management of common fractures. (United States)

    Walker, Jennie


    The incidence of fractures increases with advancing age partly due to the presence of multiple comorbidities and increased risk of falls. Common fracture sites in older people include femoral neck, distal radius and vertebral bodies. Nurses have an important role in caring for older patients who have sustained fractures, not only to maximise function and recovery, but as part of a team to minimise the morbidity and mortality associated with fractures in this group.

  7. Imaging of insufficiency fractures

    Energy Technology Data Exchange (ETDEWEB)

    Krestan, Christian [Department of Radiology, Medical University of Vienna, Vienna General Hospital, Waehringerstr. 18-20, 1090 Vienna (Austria)], E-mail:; Hojreh, Azadeh [Department of Radiology, Medical University of Vienna, Vienna General Hospital, Waehringerstr. 18-20, 1090 Vienna (Austria)


    This review focuses on the occurrence, imaging and differential diagnosis of insufficiency fractures. Prevalence, the most common sites of insufficiency fractures and their clinical implications are discussed. Insufficiency fractures occur with normal stress exerted on weakened bone. Postmenopausal osteoporosis is the most common cause of insufficiency fractures. Other conditions which affect bone turnover include osteomalacia, hyperparathyroidism, chronic renal failure and high-dose glucocorticoid therapy. It is a challenge for the radiologist to detect and diagnose insufficiency fractures, and to differentiate them from other bone lesions. Radiographs are still the most widely used imaging method for identification of insufficiency fractures, but sensitivity is limited, depending on the location of the fractures. Magnetic resonance imaging (MRI) is a very sensitive tool to visualize bone marrow abnormalities associated with insufficiency fractures. Thin section, multi-detector computed tomography (MDCT) depicts subtle fracture lines allowing direct visualization of cortical and trabecular bone. Bone scintigraphy still plays a role in detecting fractures, with good sensitivity but limited specificity. The most important differential diagnosis is underlying malignant disease leading to pathologic fractures. Bone densitometry and clinical history may also be helpful in confirming the diagnosis of insufficiency fractures.

  8. Sprains, Strains and Fractures (United States)

    ... the bone. Causes Injuries are the most common causes of foot and ankle sprains and fractures. Many fractures and sprains occur during ... or stumbling on uneven ground is another common cause of foot and ankle sprains and fractures. Symptoms Pain, swelling, bruising, and difficulty ...

  9. Obesity and fracture risk


    Gonnelli, S; Caffarelli, C.; Nuti, R.


    Obesity and osteoporosis are two common diseases with an increasing prevalence and a high impact on morbidity and mortality. Obese women have always been considered protected against osteoporosis and osteoporotic fractures. However, several recent studies have challenged the widespread belief that obesity is protective against fracture and have suggested that obesity is a risk factor for certain fractures.

  10. Experimental investigation of heat transport through single synthetic fractures (United States)

    Pastore, Nicola; Cherubini, Claudia; Giasi, Concetta I.; Redondo, Jose M.


    In fractured geothermal reservoirs, heat transport is highly influenced by the presence of the fractures, so appropriate knowledge of heat behaviour in fractured porous media is essential for accurate prediction of the energy extraction in geothermal reservoirs. The present study focuses on the study of heat transport within single synthetic fractures. In particular manner several tests have been carried out in order to explore the role of fracture roughness, aperture variability and the fracture-matrix ratio on the heat transport dynamics. The Synfrac program together with a 3d printer have been used to build several fracture planes having different geometrical characteristics that have been moulded to generate concrete porous fractured blocks. The tests regard the observation of the thermal breakthrough curves obtained through a continuous flow injection in correspondence of eight thermocouples located uniformly on the fractured blocks. The physical model developed permits to reproduce and understand adequately some features of heat transport dynamics in fractured media. The results give emphasis on the errors of the assumptions commonly used in heat transport modelling.

  11. Quantifying Representative Hydraulic Conductivity for Three-Dimensional Fractured Formations (United States)

    Lee, I.; Ni, C.


    The fractures and pores in rock formations are the fundamental units for flow and contaminant transport simulations. Due to technical and logical limitations it is difficult in reality to account for such small units to model flow and transport in large-scale problems. The concept of continuum representations of fractured rocks is then used as an alternative to solve for flow and transport in complex fractured formations. For these types of approaches the determinations of the representative parameters such as hydraulic conductivity and dispersion coefficient play important roles in controlling the accuracy of simulation results for large-scale problems. The objective of this study is to develop a discrete fracture network (DFN) model and the associated unstructured mesh generation system to characterize the continuum hydraulic conductivity for fractured rocks on different scales. In this study a coupled three-dimensional model of water flow, thermal transport, solute transport, and geochemical kinetic/equilibrium reactions in saturated/unsaturated porous media (HYDROGEOCHEM) is employed to be the flow simulator to analyze the flow behaviors in fracture formations. The fracture network model and the corresponding continuum model are simulated for same scale problems. Based on the concept of mass conservation in flow, the correlations between statistics of fracture structure and the representative continuum parameters are quantified for a variety of fracture distribution scenarios and scales. The results of this study are expected to provide general insight into the procedures and the associated techniques for analyzing flow in complex large-scale fractured rock systems.

  12. Multifocal humeral fractures. (United States)

    Maresca, A; Pascarella, R; Bettuzzi, C; Amendola, L; Politano, R; Fantasia, R; Del Torto, M


    Multifocal humeral fractures are extremely rare. These may affect the neck and the shaft, the shaft alone, or the diaphysis and the distal humerus. There is no classification of these fractures in the literature. From 2004 to 2010, 717 patients with humeral fracture were treated surgically at our department. Thirty-five patients presented with an associated fracture of the proximal and diaphyseal humerus: synthesis was performed with plate and screws in 34 patients, and the remaining patient had an open fracture that was treated with an external fixator. Mean follow-up was 3 years and 3 months. A classification is proposed in which type A fractures are those affecting the proximal and the humeral shaft, type B the diaphysis alone, and type C the diaphysis in association with the distal humerus. Type A fractures are then divided into three subgroups: A-I, undisplaced fracture of the proximal humerus and displaced shaft fracture; A-II: displaced fracture of the proximal and humeral shaft; and A-III: multifragmentary fracture affecting the proximal humerus and extending to the diaphysis. Multifocal humeral fractures are very rare and little described in the literature, both for classification and treatment. The AO classification describes bifocal fracture of the humeral diaphysis, type B and C. The classification suggested in this article mainly concerns fractures involving the proximal and humeral shaft. A simple classification of multifocal fractures is suggested to help the surgeon choose the most suitable type of synthesis for surgical treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Stress fractures in runners. (United States)

    McCormick, Frank; Nwachukwu, Benedict U; Provencher, Matthew T


    Stress fractures are a relatively common entity in athletes, in particular, runners. Physicians and health care providers should maintain a high index of suspicion for stress fractures in runners presenting with insidious onset of focal bone tenderness associated with recent changes in training intensity or regimen. It is particularly important to recognize “high-risk” fractures, as these are associated with an increased risk of complication. A patient with confirmed radiographic evidence of a high-risk stress fracture should be evaluated by an orthopedic surgeon. Runners may benefit from orthotics, cushioned sneakers, interval training, and vitamin/calcium supplementation as a means of stress fracture prevention.

  14. [Fractures of the patella]. (United States)

    Wild, M; Windolf, J; Flohé, S


    Fractures of the patella account for approximately 0.5% to 1.5% of all skeletal injuries. The diagnosis is made by means of the mechanism of injury, physical and radiological findings. The kind of treatment of patella fractures depends on the type of fracture, the size of the fragments, the integrity of the extensor mechanism and the congruity of the articular surface. Independent of the kind of treatment an early rehabilitation is recommended. Modified tension band wiring is the most commonly used surgical treatment for patella fractures and can be used for almost every type of fracture. Due the superior stability in biomechanical studies two parallel cannulated lag screws combined with a tension band wiring are the treatment of choice for horizontally displaced two-part fractures. In comminuted fractures a partial or total patellectomy may be necessary. However, since the loss of quadriceps muscle power and the poor outcome total patellectomy should be considered as a salvage procedure.

  15. Fracture in Soft Materials

    DEFF Research Database (Denmark)

    Hassager, Ole

    Fracture is a phenomenon that is generally associated with solids. A key element in fracture theory is the so-called weakest link idea that fracture initiates from the largest pre-existing material imperfection. However, recent work has demonstrated that fracture can also happen in liquids, where...... surface tension will act to suppress such imperfections. Therefore, the weakest link idea does not seem immediately applicable to fracture in liquids. This presentation will review fracture in liquids and argue that fracture in soft liquids is a material property independent of pre-existing imperfections....... The following questions then emerge: What is the material description needed to predict crack initiation, crack speed and crack shape in soft materials and liquids....

  16. Orbital fractures: a review

    Directory of Open Access Journals (Sweden)

    Jeffrey M Joseph


    Full Text Available Jeffrey M Joseph, Ioannis P GlavasDivision of Ophthalmic Plastic and Reconstructive Surgery, Department of Ophthalmology, School of Medicine, New York University, New York, NY, USA; Manhattan Eye, Ear, and Throat Hospital, New York, NY, USAAbstract: This review of orbital fractures has three goals: 1 to understand the clinically relevant orbital anatomy with regard to periorbital trauma and orbital fractures, 2 to explain how to assess and examine a patient after periorbital trauma, and 3 to understand the medical and surgical management of orbital fractures. The article aims to summarize the evaluation and management of commonly encountered orbital fractures from the ophthalmologic perspective and to provide an overview for all practicing ophthalmologists and ophthalmologists in training.Keywords: orbit, trauma, fracture, orbital floor, medial wall, zygomatic, zygomatic complex, zmc fracture, zygomaticomaxillary complex fractures 

  17. Pediatric Distal Radius Fractures. (United States)

    Dua, Karan; Abzug, Joshua M; Sesko Bauer, Andrea; Cornwall, Roger; Wyrick, Theresa O


    Distal radius fractures are the most common orthopaedic injury that occur in the pediatric population. The annual incidence of distal radius fractures has increased as a result of earlier participation in sporting activities, increased body mass index, and decreased bone mineral density. Most distal radius fractures are sustained after a fall onto an outstretched arm that results in axial compression on the extremity or from direct trauma to the extremity. Physeal fractures of the distal radius are described based on the Salter-Harris classification system. Extraphyseal fractures of the distal radius are described as incomplete or complete based on the amount of cortical involvement. A thorough physical examination of the upper extremity is necessary to rule out any associated injuries. PA and lateral radiographs of the wrist usually are sufficient to diagnose a distal radius fracture. The management of distal radius fractures is based on several factors, including patient age, fracture pattern, and the amount of growth remaining. Nonsurgical management is the most common treatment option for patients who have distal radius fractures because marked potential for remodeling exists. If substantial angulation or displacement is present, closed reduction maneuvers with or without percutaneous pinning should be performed. Patients with physeal fractures of the distal radius that may result in malunion who present more than 10 days postinjury should not undergo manipulation of any kind because of the increased risk for physeal arrest.

  18. Odontoid Fracture: Computed Tomography

    Directory of Open Access Journals (Sweden)

    Jonathan Peña


    Full Text Available History of present illness: An 84-year-old male presented with left-sided posterior head, neck, and back pain after a ground level fall. Exam was notable for left parietal scalp laceration and midline cervical spine tenderness with no obvious deformities. He was neurovascularly intact, and placed in an Aspen Collar with strict spine precautions. Significant findings: Computed Tomography (CT of the cervical spine showed a stable, acute, non-displaced fracture of the odontoid process extending into the body of C2, consistent with a Type III Odontoid Fracture. He was evaluated by orthopedic spine service who recommended conservative, non-operative management. Discussion: The cervical spine is composed of seven vertebrae, with C1 and C2 commonly referred to as the Atlas and Axis, respectively. Unique to C2 is a bony prominence, the Odontoid Process (Dens. Hyperextension or hyperflexion injuries can induce significant stress causing fractures. Odontoid fractures comprise approximately 10% of vertebral fractures, and there are three types with varying stability.1 Type 1 is the rarest and is a fracture involving the superior segment of the Dens. It is considered a stable fracture. Type 2 is the most common and is a fracture involving the base of the odontoid process, below the transverse component of the cruciform ligament. This fracture is unstable and requires operative stabilization. 2 Type 3 odontoid fractures are classified by a fracture of the Odontoid process, as well as the lateral masses of the C2. Determining the stability of a Type III Odontoid fracture requires radiographic evaluation. Strict cervical spine precautions must be adhered to until adequate imaging and surgical consultation is obtained. CT of the of cervical spine fractures poses several advantages to plain film radiography due to the ability to view the anatomy in three planes. 3 However, if there is concern for ligamentous injury, MRI is the preferred modality.3

  19. Morphology Analysis of Cu Film Fractures in Sandwiched Methylmethacrylate Plates

    Directory of Open Access Journals (Sweden)

    Cristiano Fidani


    Full Text Available Thin films of Cu were evaporated on solid plates of polymethylmethacrylate (PMMA. A polymerization process was made to realize sandwiched structure to protect the Cu films. Fracturing of the metal film surface was observed with several morphologies showing two different fracture systems. Surface film morphology was analysed in terms of the distribution area of the islands and contour fractal dimension. The island areas showed a maximum corresponding to 42 nm of the Cu thickness, it was also the threshold to observe the second fracture system. The fractures pattern resulted to be scale invariant with fractal dimensions between 1.55 and 1.7. The minimum fractal dimension also occurred at the film thickness corresponding to the maximum island area. The reported effects can be understood on the basis of different thermal expansion coefficients of the two materials and their thermally induced adhesion.DOI:

  20. Overview of Intergranular Fracture of Neutron Irradiated Austenitic Stainless Steels

    Directory of Open Access Journals (Sweden)

    Anna Hojná


    Full Text Available Austenitic stainless steels are normally ductile and exhibit deep dimples on fracture surfaces. These steels can, however, exhibit brittle intergranular fracture under some circumstances. The occurrence of intergranular fracture in the irradiated steels is briefly reviewed based on limited literature data. The data are sorted according to the irradiation temperature. Intergranular fracture may occur in association with a high irradiation temperature and void swelling. At low irradiation temperature, the steels can exhibit intergranular fracture at low or even at room temperatures during loading in air and in high temperature water (~300 °C. This paper deals with the similarities and differences for IG fractures and discusses the mechanisms involved. The intergranular fracture occurrence at low temperatures might be correlated with decohesion or twinning and strain martensite transformation in local narrow areas around grain boundaries. The possibility of a ductile-to-brittle transition is also discussed. In case of void swelling higher than 3%, quasi-cleavage at low temperature might be expected as a consequence of ductile-to-brittle fracture changes with temperature. Any existence of the change in fracture behavior in the steels of present thermal reactor internals with increasing irradiation dose should be clearly proven or disproven. Further studies to clarify the mechanism are recommended.

  1. In vivo shell-like fractures of veneered-ZrO2 fixed dental prostheses

    Directory of Open Access Journals (Sweden)

    Renan Belli


    Full Text Available Fractographic analyses are performed in two fixed dental prosthetic reconstructions made of ZrO2 frameworks covered by a veneering ceramic that fractured during function in the mouth. Processing histories, material properties, recovered broken parts and replicas of the fracture surface were used, along with fractographic markings to determine fracture origins and cause of failure. A shell-like fracture pattern was found common for both cases, although different factors were identified to be involved in each fracture event. Internal thermal residual stresses and occlusal surface defects from localized contact overloading were found to precipitate the fracture in Case 1, whereas extreme occlusal surface damage from sliding chewing contact was determinant in the fracture of Case 2. The interface between the veneering ceramic and the ZrO2 framework was unaffected by the fractures.

  2. Hygrothermomechanical fracture stress criteria for fiber composites with sense-parity (United States)

    Chamis, C. C.; Ginty, C. A.


    Hygrothermomechanical fracture stress criteria are developed and evaluated for unidirectional composites (plies) with sense-parity. These criteria explicity quantify the individual contributions of applied, hygral and thermal stresses as well as couplings among these stresses. The criteria are for maximum stress, maximum strain, internal friction, work-to-fracture and combined-stress fracture. Predicted results obtained indicate that first ply failure will occur at stress levels lower than those predicted using criteria currently available in the literature. Also, the contribution of the various stress couplings (predictable only by fracture criteria with sense-parity) is significant to first ply failure and attendant fracture modes.

  3. -Lesser known stress fractures-. (United States)

    Wybier, M; Hamze, B; Champsaur, P; Parlier, C


    Stress fractures of the tibia may disclose a longitudinal orientation which is obvious at bone scanning; a mild periostosis may appear on plain films; CT demonstrates a radially-oriented fracture in one aspect of the diaphyseal cortex. A cortical dissection-like vertically oriented insufficiency fracture may involve the medial aspect of the femoral shaft underlying the lesser trochanter; the fracture is concentric to the femoral cortex at CT. Insufficiency fractures of the sacrum may be misdiagnosed on plain films; bone scanning displays a typical H-shaped increased uptake which is a specific pattern. Insufficiency fractures of the pubis may appear as tumoral bone destruction; however no soft tissue mass is present at CT which in addition demonstrates normal fat tissue abutting the osseous lesion.

  4. Discrete Fracture Network Characterization of Fractured Shale Reservoirs with Implications to Hydraulic Fracturing Optimization (United States)

    Jin, G.


    Shales are important petroleum source rocks and reservoir seals. Recent developments in hydraulic fracturing technology have facilitated high gas production rates from shale and have had a strong impact on the U.S. gas supply and markets. Modeling of effective permeability for fractured shale reservoirs has been challenging because the presence of a fracture network significantly alters the reservoir hydrologic properties. Due to the frequent occurrence of fracture networks, it is of vital importance to characterize fracture networks and to investigate how these networks can be used to optimize the hydraulic fracturing. We have conducted basic research on 3-D fracture permeability characterization and compartmentization analyses for fractured shale formations, which takes the advantages of the discrete fracture networks (DFN). The DFN modeling is a stochastic modeling approach using the probabilistic density functions of fractures. Three common scenarios of DFN models have been studied for fracture permeability mapping using our previously proposed techniques. In DFN models with moderately to highly concentrated fractures, there exists a representative element volume (REV) for fracture permeability characterization, which indicates that the fractured reservoirs can be treated as anisotropic homogeneous media. Hydraulic fracturing will be most effective if the orientation of the hydraulic fracture is perpendicular to the mean direction of the fractures. A DFN model with randomized fracture orientations, on the other hand, lacks an REV for fracture characterization. Therefore, a fracture permeability tensor has to be computed from each element. Modeling of fracture interconnectivity indicates that there exists no preferred direction for hydraulic fracturing to be most effective oweing to the interconnected pathways of the fracture network. 3-D fracture permeability mapping has been applied to the Devonian Chattanooga Shale in Alabama and the results suggest that an

  5. Proximal humeral fractures


    Mauro, Craig S.


    Proximal humeral fractures may present with many different configurations in patients with varying co-morbities and expectations. As a result, the treating physician must understand the fracture pattern, the quality of the bone, other patient-related factors, and the expanding range of reconstructive options to achieve the best functional outcome and to minimize complications. Current treatment options range from non-operative treatment with physical therapy to fracture fixation using percuta...

  6. Sphenotemporal buttress fracture

    Energy Technology Data Exchange (ETDEWEB)

    Jend, H.H.; Jend-Rossmann, I.


    A new fracture type visible of CT images of the base of the skull is described. In this fracture the sphenoidal connection to the zygomatic and temporal bone breaks off all its three extensions. It was recognized in five patients with severe head injuries. In three surviving patients it was associated with ipsilateral persistent amaurosis. This fracture should alert the investigator to the possible sequelae of the head injury.

  7. Scaphoid fractures in children

    Directory of Open Access Journals (Sweden)

    Gajdobranski Đorđe


    Full Text Available Introduction. Scaphoid fractures are rare in childhood. Diagnosis is very difficult to establish because carpal bones are not fully ossified. In suspected cases comparative or delayed radiography is used, as well as computerized tomography, magnetic resonance imaging, ultrasound and bone scintigraphy. Majority of scaphoid fractures are treated conservatively with good results. In case of delayed fracture healing various types of treatment are available. Objective. To determine the mechanism of injury, clinical healing process, types and outcome of treatment of scaphoid fractures in children. Methods. We retrospectively analyzed patients with traumatic closed fracture of the scaphoid bone over a ten-year period (2002-2011. The outcome of the treatment of “acute” scaphoid fracture was evaluated using the Mayo Wrist Score. Results. There were in total 34 patients, of mean age 13.8 years, with traumatic closed fracture of the scaphoid bone, whose bone growth was not finished yet. Most common injury mechanism was fall on outstretched arm - 76% of patients. During the examined period 31 children with “acute” fracture underwent conservative treatment, with average immobilization period of 51 days. Six patients were lost to follow-up. In the remaining 25 patients, after completed rehabilitation, functional results determined by the Mayo Wrist Score were excellent. Conclusion. Conservative therapy of “acute” scaphoid fractures is an acceptable treatment option for pediatric patients with excellent functional results.

  8. Hip fracture after hemiplegia. (United States)

    Mulley, G.; Espley, A. J.


    In a series of 57 hemiplegic patients who subsequently fractured their hips, it was found that hip fracture occurred significantly more often on the hemiplegic side. Hip fracture was equally common in right- and left-sided hemiplegia, and often occurred within one year of the stroke. Two factors seem to be important in the genesis of hip fractures in hemiplegic patients: the tendency of stroke patients to fall to the affected side as a result of impaired locomotor function, and the development of disuse osteoporosis in the hemiplegic limb. PMID:471862

  9. [Fractures of the midfoot]. (United States)

    Boack, D H


    The immediate reduction of luxations and severe dislocations is necessary to protect the soft tissue. The soft tissue lesions determine the timing and partially the options of the operative treatment too. The conventional standard X-rays are sufficient to classify most of the fractures. Conservative treatment or minimal-invasive intramedullary techniques of fixation are sufficient in the treatment in most of the fractures. Screw- and plate-osteosynthesis are a good choice only in intra-articular fractures or sometimes in fractures of the first or fifth metatarsals. The clinical outcome is almost good and the rate of complications is low.

  10. Pathological fractures in children (United States)

    De Mattos, C. B. R.; Binitie, O.; Dormans, J. P.


    Pathological fractures in children can occur as a result of a variety of conditions, ranging from metabolic diseases and infection to tumours. Fractures through benign and malignant bone tumours should be recognised and managed appropriately by the treating orthopaedic surgeon. The most common benign bone tumours that cause pathological fractures in children are unicameral bone cysts, aneurysmal bone cysts, non-ossifying fibromas and fibrous dysplasia. Although pathological fractures through a primary bone malignancy are rare, these should be recognised quickly in order to achieve better outcomes. A thorough history, physical examination and review of plain radiographs are crucial to determine the cause and guide treatment. In most benign cases the fracture will heal and the lesion can be addressed at the time of the fracture, or after the fracture is healed. A step-wise and multidisciplinary approach is necessary in caring for paediatric patients with malignancies. Pathological fractures do not have to be treated by amputation; these fractures can heal and limb salvage can be performed when indicated. PMID:23610658

  11. Treatment of forearm fractures

    National Research Council Canada - National Science Library

    Macintyre, N R; Ilyas, A M; Jupiter, J B


    Fractures of the forearm represent common injuries. Understanding the anatomy and function of the radius, ulna, interosseous membrane, proximal and distal radioulnar joints is critical to appropriate management...

  12. Bracing for thoracolumbar fractures. (United States)

    Chang, Victor; Holly, Langston T


    Traumatic fractures of the thoracolumbar spine are relatively common occurrences that can be a source of pain and disability. Similarly, osteoporotic vertebral fractures are also frequent events and represent a significant health issue specific to the elderly. Neurologically intact patients with traumatic thoracolumbar fractures can commonly be treated nonoperatively with bracing. Nonoperative treatment is not suitable for patients with neurological deficits or highly unstable fractures. The role of operative versus nonoperative treatment of burst fractures is controversial, with high-quality evidence supporting both options. Osteoporotic vertebral fractures can be managed with bracing or vertebral augmentation in most cases. There is, however, a lack of high-quality evidence comparing operative versus nonoperative fractures in this population. Bracing is a low-risk, cost-effective method to treat certain thoracolumbar fractures and offers efficacy equivalent to that of surgical management in many cases. The evidence for bracing of osteoporotic-type fractures is less clear, and further investigation will be necessary to delineate its optimal role.

  13. Pediatric Scaphoid Fractures. (United States)

    Ting, Beverlie; Sesko Bauer, Andrea; Abzug, Joshua M; Cornwall, Roger; Wyrick, Theresa O; Bae, Donald S


    Scaphoid fractures are the most common type of carpal injuries that occur in children and adolescents. The injury pattern seen in children and adolescents who have scaphoid fractures has recently shifted to resemble that of adults who have scaphoid fractures, with scaphoid waist fractures being the most common injury pattern. This shift has been attributed to increased body mass index in children and adolescents as well as more intense participation in extreme sports by both children and adolescents. The diagnosis of scaphoid fractures is based on both a clinical examination and radiographic fi ndings. If a scaphoid fracture is clinically suspected but initial radiographs are negative, cast immobilization followed by repeat imaging can lead to accurate diagnosis of the injury. MRI can aid in the diagnosis of a scaphoid injury in pediatric patients with incomplete ossifi cation of the scaphoid. Acute nondisplaced scaphoid fractures have a high rate of healing with cast immobilization; however, surgery should be considered in patients who have displaced scaphoid fractures with delayed presentation. In general, patients with scaphoid fractures who undergo appropriate treatment and achieve successful union have excellent long-term functional outcomes.

  14. Fracture of the styloid process associated with the mandible fracture

    Directory of Open Access Journals (Sweden)

    K N Dubey


    Full Text Available Fracture of the styloid process (SP of temporal bone is an uncommon injuries. Fracture of the SP can be associated with the facial injuries including mandible fracture. However, injury to the SP may be concealed and missed diagnosis may lead to the improper or various unnecessary treatments. A rare case of SP fracture associated with the ipsilateral mandibular fracture and also the diagnostic and management considerations of the SP fracture are discussed.

  15. Three-Dimensional Modeling of Fracture Clusters in Geothermal Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ghassemi, Ahmad [Univ. of Oklahoma, Norman, OK (United States)


    The objective of this is to develop a 3-D numerical model for simulating mode I, II, and III (tensile, shear, and out-of-plane) propagation of multiple fractures and fracture clusters to accurately predict geothermal reservoir stimulation using the virtual multi-dimensional internal bond (VMIB). Effective development of enhanced geothermal systems can significantly benefit from improved modeling of hydraulic fracturing. In geothermal reservoirs, where the temperature can reach or exceed 350oC, thermal and poro-mechanical processes play an important role in fracture initiation and propagation. In this project hydraulic fracturing of hot subsurface rock mass will be numerically modeled by extending the virtual multiple internal bond theory and implementing it in a finite element code, WARP3D, a three-dimensional finite element code for solid mechanics. The new constitutive model along with the poro-thermoelastic computational algorithms will allow modeling the initiation and propagation of clusters of fractures, and extension of pre-existing fractures. The work will enable the industry to realistically model stimulation of geothermal reservoirs. The project addresses the Geothermal Technologies Office objective of accurately predicting geothermal reservoir stimulation (GTO technology priority item). The project goal will be attained by: (i) development of the VMIB method for application to 3D analysis of fracture clusters; (ii) development of poro- and thermoelastic material sub-routines for use in 3D finite element code WARP3D; (iii) implementation of VMIB and the new material routines in WARP3D to enable simulation of clusters of fractures while accounting for the effects of the pore pressure, thermal stress and inelastic deformation; (iv) simulation of 3D fracture propagation and coalescence and formation of clusters, and comparison with laboratory compression tests; and (v) application of the model to interpretation of injection experiments (planned by our

  16. Hip Fractures among Older Adults (United States)

    ... online training for health care providers. Learn More Hip Fractures Among Older Adults Recommend on Facebook Tweet Share ... get older. What You Can Do to Prevent Hip Fractures You can prevent hip fractures by taking steps ...

  17. Compression fractures of the back (United States)

    ... most effective way to prevent compression or insufficiency fractures. Getting regular load-bearing exercise (such as walking) can help you avoid bone loss. Alternative Names Vertebral compression fractures Images Compression fracture References Cosman F, de Beur ...

  18. The Process of Hydraulic Fracturing (United States)

    Hydraulic fracturing, know as fracking or hydrofracking, produces fractures in a rock formation by pumping fluids (water, proppant, and chemical additives) at high pressure down a wellbore. These fractures stimulate the flow of natural gas or oil.

  19. Fracture characterization in a deep geothermal reservoir (United States)

    Rühaak, Wolfram; Hehn, Vera; Hassanzadegan, Alireza; Tischner, Torsten


    At the geothermal research drilling Horstberg in North West Germany studies for the characterization of a vertical fracture are performed. The fracture was created by a massive hydraulic stimulation in 2003 in approx. 3700 m depth within rocks of the middle Buntsandstein. The fracture surface is in the order of 100,000 m2, depending on the flow rate at which water is injected. Besides hydraulic characterization, multiple tracer tests are planned. At the depth of interest the reservoir temperature is around 150 °C, pressure is around 600 bar (60 MPa) and due to salinity the water density is around 1200 kg/m3. Knowledge of tracer stability and behavior at these reservoir conditions is limited. Additionally, the planned tracer tests will be performed within one single borehole. In a closed cycle water is injected into the inner pipe of the well (tubing), which is separated by a permanent packer from the outer pipe (annulus). The water is produced back from the annulus approximately 150 m above the injection point. Thus, the circulation of thermal water between two sandstone layers via an artificial fracture can be achieved. Tests will be carried out with different flow rates and accordingly with different pressures, resulting in different fracture areas. Due to this test setup tracer signals will be stacked and will remain for a longer time in the fracture - which is the reason why different tracers are required. For an optimal characterization both conservative and reactive tracers will be used and different injection methods (continuous, instantaneous and pulsed) will be applied. For a proper setup of the tracer test numerical modelling studies are performed in advance. The relevant thermal, hydraulic and chemical processes (mainly adsorption and degredation) are coupled, resulting in a THC model; additionally the dependence of fracture aperture and area on fluid pressure has to be considered. Instead of applying a mechanically coupled model (THMC) a simplified

  20. Displaced patella fractures. (United States)

    Della Rocca, Gregory J


    Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  1. Vertebral Fracture Prediction

    DEFF Research Database (Denmark)


    Vertebral Fracture Prediction A method of processing data derived from an image of at least part of a spine is provided for estimating the risk of a future fracture in vertebraeof the spine. Position data relating to at least four neighbouring vertebrae of the spine is processed. The curvature...

  2. Atypical femoral fractures

    African Journals Online (AJOL)


    Jan 24, 2013 ... A 73 year-old female patient was admitted to the orthogeriatrics unit at Helen Joseph Hospital in 2012 with a fracture of her right femur, following a fall from standing height. She was known to have severe osteoporosis, having sustained multiple previous fragility fractures involving her right distal radius, left ...

  3. Coupled Three-Dimensional Fracture Stimulation and Prediction Model for Enhanced Geothermal Systems (United States)

    Kumar, D.; Gutierrez, M.


    The paper presents development of a three-dimensional fracture stimulation and prediction model using the Boundary Element Method (BEM) for Enhanced Geothermal Systems (EGS). The BEM method results in a numerical procedure which eliminates discretization of complete reservoir domain; hence, only the fracture surface discretization is required. The Displacement Discontinuity Method which is an invariant of the BEM was used to model the fracture geometry (e.g., fracture width, length and elongation), fluid pressure and stress distribution around the fracture. The main feature of the model is that it is able to handle true three-dimensional fractures that can twist turn and not just planar or pseudo three-dimensional fracture geometries. The numerical aspects of various mechanisms involved in the hydraulic fracturing process in the EGS such as fracture deformation, fluid flow and heat flow, fracture initiation and propagation were addressed. The laminar fracture fluid flow and transient heat flow were modeled using the Finite Element Method. The non-Newtonian fluid flow behavior was assumed. Temperature-dependent fluid and rock physical properties were used. The fracture same mesh was used to model for the fracture deformation, fluid flow and heat flow processes. The fracture surface was discretized using 4-node rectangular elements. The important numerical issues of the BEM implementation for the fracture modeling such as near singular, hypersingular cases and crack tip singularity were taken into account. The processes involved in hydraulic fracturing are interdependent. The fracture aperture strongly influences the fluid flow rate inside the fracture, as the fluid velocity is proportional to its width. Thermal-induced stresses effects the fracture aperture. These fully coupled processes of fluid flow, heat flow, and fracture deformation were solved in a coupled manner using iterative method. One of the main challenges of this research was to couple the thermal

  4. Dating fractures in infants

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, K.E., E-mail: [Department of Radiology, Nottingham University Hospitals, Queen' s Medical Centre, Nottingham (United Kingdom); Broderick, N.J.; Somers, J.M. [Department of Radiology, Nottingham University Hospitals, Queen' s Medical Centre, Nottingham (United Kingdom); Hawkes, R. [Department of Radiology, Paul O' Gorman Building, Bristol (United Kingdom)


    Aim: To document the timing of the appearance of the radiological features of fracture healing in a group of infants in which the date of injury was known and to assess the degree of interobserver agreement. Materials and methods: Three paediatric radiologists independently assessed 161 images of 37 long bone fractures in 31 patients aged 0-44 months. The following features were assessed: soft-tissue swelling, subperiosteal new bone formation (SPNBF), definition of fracture line, presence or absence of callus, whether callus was well or ill defined, and the presence of endosteal callus. Results: Agreement between observers was only moderate for all discriminators except SPNBF. SPNBF was invariably seen after 11 days but was uncommon before this time even in the very young. In one case SPNBF was seen at 4 days. Conclusion: With the exception of SPNBF, the criteria relied on to date fractures are either not reproducible or are poor discriminators of fracture age.

  5. Proximal femoral fractures

    DEFF Research Database (Denmark)

    Palm, Henrik; Teixidor, Jordi


    -displaced femoral neck fractures and prosthesis for displaced among the elderly; and sliding hip screw for stabile- and intramedullary nails for unstable- and sub-trochanteric fractures) but they are based on a variety of criteria and definitions - and often leave wide space for the individual surgeons' subjective...... guidelines for hip fracture surgery and discuss a method for future pathway/guideline implementation and evaluation. METHODS: By a PubMed search in March 2015 six studies of surgical treatment pathways covering all types of proximal femoral fractures with publication after 1995 were identified. Also we...... searched the homepages of the national heath authorities and national orthopedic societies in West Europe and found 11 national or regional (in case of no national) guidelines including any type of proximal femoral fracture surgery. RESULTS: Pathway consensus is outspread (internal fixation for un...

  6. Tibial Plateau Fractures

    DEFF Research Database (Denmark)

    Elsøe, Rasmus

    This PhD thesis reported an incidence of tibial plateau fractures of 10.3/100,000/year in a complete Danish regional population. The results reported that patients treated for a lateral tibial plateau fracture with bone tamp reduction and percutaneous screw fixation achieved a satisfactory level...... with only the subgroup Sport significantly below the age matched reference population. The thesis reports a level of health related quality of life (Eq5d) and disability (KOOS) significantly below established reference populations for patients with bicondylar tibial plateau fracture treated with a ring...... fixator, both during treatment and at 19 months following injury. In general, the thesis demonstrates that the treatment of tibial plateau fractures are challenging and that some disabilities following these fractures must be expected. Moreover, the need for further research in the area, both with regard...

  7. Thermal imaging in medicine

    Directory of Open Access Journals (Sweden)

    Jaka Ogorevc


    Full Text Available AbstractIntroduction: Body temperature monitoring is one of the oldest and still one of the most basic diagnostic methods in medicine. In recent years thermal imaging has been increasingly used in measurements of body temperature for diagnostic purposes. Thermal imaging is non-invasive, non-contact method for measuring surface body temperature. Method is quick, painless and patient is not exposed to ionizing radiation or any other body burden.Application of thermal imaging in medicine: Pathological conditions can be indicated as hyper- or hypothermic patterns in many cases. Thermal imaging is presented as a diagnostic method, which can detect such thermal anomalies. This article provides an overview of the thermal imaging applications in various fields of medicine. Thermal imaging has proven to be a suitable method for human febrile temperature screening, for the detection of sites of fractures and infections, a reliable diagnostic tool in the detection of breast cancer and determining the type of skin cancer tumour. It is useful in monitoring the course of a therapy after spinal cord injury, in the detection of food allergies and detecting complications at hemodialysis and is also very effective at the course of treatment of breast reconstruction after mastectomy. With thermal imaging is possible to determine the degrees of burns and early detection of osteomyelitis in diabetic foot phenomenon. The most common and the oldest application of thermal imaging in medicine is the field of rheumatology.Recommendations for use and standards: Essential performance of a thermal imaging camera, measurement method, preparation of a patient and environmental conditions are very important for proper interpretation of measurement results in medical applications of thermal imaging. Standard for screening thermographs was formed for the human febrile temperature screening application.Conclusion: Based on presented examples it is shown that thermal imaging can

  8. Bone fractures after menopause. (United States)


    Every year 30% of individuals above age 65 fall, and falls are the principal cause of bone fractures. To reduce fracture incidence requires both prevention of falls and maintenance of bone strength. PubMed searches were performed, for studies of the epidemiology of fractures, bone physiology, endocrine effects, osteoporosis measurement, genetics, prevention and effectiveness. Topic summaries were presented to the Workshop Group and omissions or disagreements were resolved by discussion. Ageing reduces bone strength in post-menopausal women because estrogen deficiency causes accelerated bone resorption. Bone mineral density (BMD) decreased more than 2.5 standard deviation below the mean of healthy young adults defines osteoporosis, a condition associated with an increased risk of fractures. Risk factors such as age and previous fracture are combined with BMD for a more accurate prediction of fracture risk. The most widely used assessment tool is FRAX™ which combines clinical risk factors and femoral neck BMD. General preventive measures include physical exercise to reduce the risk of falling and vitamin D to facilitate calcium absorption. Pharmacological interventions consist mainly in the administration of inhibitors of bone resorption. Randomized controlled trials show treatment improves BMD, and may reduce the relative fracture risk by about 50% for vertebral, 20-25% for non-vertebral and up to 40% for hip fractures although the absolute risk reductions are much lower. Although diagnosis of osteoporosis is an important step, the threshold for treatment to prevent fractures depends on additional clinical risk factors. None of the presently available treatment options provide complete fracture prevention.

  9. Femoral Neck Fracture

    Directory of Open Access Journals (Sweden)

    Jonathan Lee


    Full Text Available History of present illness: A 74-year-old male presented to the emergency department with left hip pain after falling off his bicycle. Pain is 3/10 in severity and exacerbated by movement. Patient denied head trauma. Exam showed left hip tenderness, 3/5 left lower extremity strength secondary to pain, and 5/5 right lower extremity strength. Sensation and pulses were intact in bilateral lower extremities. Left hip X-ray and pelvic CT revealed comminuted, impacted transcervical and subcapital fracture of the left femoral neck. Significant findings: In the anteroposterior view bilateral hip x-ray, there is an evident loss of Shenton’s line on the left (red line when compared to the normal right (white line, indicative of a fracture in the left femoral neck. This correlates with findings seen on pelvic CT, which reveals both a subcapital fracture (blue arrow and transcervical fracture (yellow arrow. The neck of the femur is displaced superiorly relative to the head of the femur while the head of the femur remains in its anatomical position within the acetabulum. Discussion: Femoral neck fractures are one of the most common types of hip fractures, accounting for 49.4% of all hip fractures.1 Diagnosing a femoral neck fracture can be made with plain x-ray, CT, or MRI. Plain film radiographs have been found to be at least 90% sensitive for hip fractures CT’s have been found to be 87%-100% sensitive and 100% specific for occult hip fractures in which plain radiographs were read as negative, but the patient still complained of hip pain Although MRI is currently the gold standard for detecting occult hip fractures (sensitivity and specificity = 100%, given MRI’s limited accessibility in the ED as well as the high sensitivity and specificity of CT scans for occult hip fractures, it is generally recommended to obtain CT scans for patients with suspected occult hip fractures as a first-line investigation

  10. Spontaneous rib fractures. (United States)

    Katrancioglu, Ozgur; Akkas, Yucel; Arslan, Sulhattin; Sahin, Ekber


    Other than trauma, rib fracture can occur spontaneously due to a severe cough or sneeze. In this study, patients with spontaneous rib fractures were analyzed according to age, sex, underlying pathology, treatment, and complications. Twelve patients who presented between February 2009 and February 2011 with spontaneous rib fracture were reviewed retrospectively. The patients' data were evaluated according to anamnesis, physical examination, and chest radiographs. The ages of the patients ranged from 34 to 77 years (mean 55.91 ± 12.20 years), and 7 (58.4%) were male. All patients had severe cough and chest pain. The fractures were most frequently between 4th and 9th ribs; multiple rib fractures were detected in 5 (41.7%) patients. Eight (66.7%) patients had chronic obstructive pulmonary disease, 2 (16.7%) had bronchial asthma, and 2 (16.7%) had osteoporosis. Bone densitometry revealed a high risk of bone fracture in all patients. Patients with chronic obstructive pulmonary disease or bronchial asthma had been treated with high-dose steroids for over a year. Spontaneous rib fracture due to severe cough may occur in patients with osteoporosis, chronic obstructive pulmonary disease, or bronchial asthma, receiving long-term steroid therapy. If these patients have severe chest pain, chest radiography should be performed to check for bone lesions. © The Author(s) 2015.

  11. Pediatric Supracondylar Fracture

    Directory of Open Access Journals (Sweden)

    Jonathan Peña


    Full Text Available History of present illness: A 7-year-old left-handed male presented with left arm pain and deformity after being tackled while playing. On exam, there appeared to be dorsal displacement of the distal segment of the upper extremity. He had two-plus radial and ulnar pulses, and normal capillary refill. Sensation was intact to axillary, radial, ulnar, and median nerve distributions. Compartments were soft. Significant findings: Plain film radiography showed a displaced supracondylar fracture with disrupted anterior and posterior periostea, consistent with a type 3 supracondylar fracture. Discussion: Supracondylar fractures are the most common pediatric elbow fracture.1 Approximately 95% are due to a fall onto an outstretched hand while the elbow is in extension. Direct trauma to the posterior aspect of a flexed elbow accounts for the remainder.2 There are three classifications of supracondylar fractures: type 1 is non-displaced, type 2 is displaced, but has an intact posterior periosteum, and type 3 is displaced with disrupted anterior and posterior periostea. Careful examination assessing for pulses, perfusion, neurologic integrity, and elevated compartment pressures are important in the evaluation.3 The brachial artery is often injured in posterior lateral displaced fractures.4 Neurologic deficits to the median, ulnar, or radial nerves are seen in as many of 49% of Type 3 supracondylar fractures; however, neuropraxias often resolve within two to three months.5 Untimely treated compartment syndrome may lead to Volkmann ischemic contractors, which are characterized by flexion of the elbow, pronation of the forearm, flexion of the wrist, and extension of the metacarpal phalangeal joints.6 Plain film radiography oriented in the anterior-posterior (AP and lateral fashions are typically sufficient for diagnosis; however, a fracture may exist without overt signs on X-ray.7 Given the high morbidity associated with Type 3 fractures, emergent Orthopedic

  12. A Rare Nasal Bone Fracture: Anterior Nasal Spine Fracture

    Directory of Open Access Journals (Sweden)

    Egemen Kucuk


    Full Text Available Anterior nasal spine fractures are a quite rare type of nasal bone fractures. Associated cervical spine injuries are more dangerous than the nasal bone fracture. A case of the anterior nasal spine fracture, in a 18-year-old male was presented. Fracture of the anterior nasal spine, should be considered in the differential diagnosis of the midface injuries and also accompanying cervical spine injury should not be ignored.

  13. Synthesis of Subsurface Fracture Characteristics at Yucca Mountain, Nevada (United States)

    Smart, K. J.; Wyrick, D. Y.; Landis, P. S.; Waiting, D. J.


    Fractures are among the most abundant geologic structures found in rocks. Although individual fractures are rarely of great importance, the sheer number of fractures makes them a key component of many geologic and engineering-related processes. Fractures directly affect geotechnical processes for stability of underground openings and indirectly influence processes such as thermal stress accommodation. Near-surface water infiltration and flow, and unsaturated zone radionuclide transport are tunnel- and mountain-scale processes influenced by fractures. Yucca Mountain, Nevada is the site of the United States' potential high-level nuclear waste repository. This presentation provides an up-to-date synthesis of subsurface fracture data collected in the repository host horizon interval from two tunnels, the Exploratory Studies Facility (ESF) and the Enhanced Characterization of the Repository Block (ECRB) cross-drift at Yucca Mountain. The primary goals are to: (1) summarize fracture data collected by both detailed line survey and full-periphery geologic mapping techniques; and (2) provide a rigorous analysis of key fracture characteristics, including fracture orientation, spacing and size. Definitive cooling joints and vapor phase partings are present in all zones within the Topopah Spring Tuff (the proposed repository host horizon), but are not abundant and represent only 5 to 11% of all recorded fractures. Fractures with measurable displacement are also present, but account for only 3 to 4% of the total population. These fractures, however, are predominantly subvertical with either a northwest or northeast strike. Regardless of lithostratigraphic interval (i.e., presence or absence of lithophysae), distinctive orientation-based fracture sets are present -- fractures are not randomly distributed. This observation holds for analyses of long and short fractures. The overall distribution of fracture size based on observed trace length is strongly skewed with short

  14. Fracture eponyms: personal names

    Directory of Open Access Journals (Sweden)

    A. S. Zolotov


    Full Text Available The paper describes the origin of bone fracture eponyms. The authors compiled a list of 60 most established fracture names proposed by physicians in 16th-20th centuries who mainly were skilled, mature and outstanding experts from countries with advanced conventional medicine and often represented the recognized surgical schools. Eponym records are important for understanding the history and subject of the chosen profession as well as knowledge of eponymic fractures facilitates communication between physicians of allied disciplines.

  15. Synchrotron quantification of fracturing during maturation of shales (United States)

    Figueroa Pilz, Fernando; Fauchille, Anne-Laure; Dowey, Patrick; Courtois, Loic; Bay, Brian; Ma, Lin; Taylor, Kevin; Mecklenburgh, Julian; Lee, Peter


    To understand both the hydrocarbon migration within and from shale rocks, and during hydraulic fracturing, is needed to evaluate and predict its environmental footprint. As a consequence, the time characterization of fracture networks in shale is particularly important. Time resolved synchrotron X-ray tomography was used to quantify the initiation and propagation of fractures during the simulated maturation of an organic-rich Kimmeridge Clay shale from the µm to mm scales. Scanning electron microscopy (SEM) observations were performed before and after maturation in order to compare the microstructure evolution and better understand the fracture location. Fracture and strain development during heating was quantified in 3D by Digital Volume Correlation (DVC) (Bay et al., 1999). The combination of DVC, X-Ray tomography and SEM obtained direct 4D strain measurements of the anisotropic mechanical behaviour of Kimmeridge shale with the temperature during an accelerated thermal maturation (Figueroa Pilz et al.). Such a combination has rarely been investigated in 4D at these scales in the past. In the study conditions, the results demonstrated the anisotropy in thermal expansion and the aperture fracture pathways through organic matter and clay matrix.

  16. Tibial shaft fracture

    DEFF Research Database (Denmark)

    Larsen, Peter

    The overall purpose of the present PhD thesis was to provide up-to-date information of the epidemiology of tibial shaft fractures and to investigate the development in quality of life, pain and functional outcomes from surgery and onwards, following a tibial shaft fracture treated...... with intramedullary nailing. Study I reported an incidence of 16.9/100,000/year from a complete population. Study II reported the long-term patient-reported outcomes and showed that approximately 8 years after the fracture patients reported significantly worse outcome for 4 of the 5 KOOS subscales compared...... suggested that regaining pre injured QOL and muscle strength following a tibial shaft fracture takes considerable time....

  17. Paediatric talus fracture.

    LENUS (Irish Health Repository)

    Byrne, Ann-Maria


    Paediatric talus fractures are rare injuries resulting from axial loading of the talus against the anterior tibia with the foot in dorsiflexion. Skeletally immature bone is less brittle, with higher elastic resistance than adult bone, thus the paediatric talus can sustain higher forces before fractures occur. However, displaced paediatric talus fractures and those associated with high-energy trauma have been associated with complications including avascular necrosis, arthrosis, delayed union, neurapraxia and the need for revision surgery. The authors present the rare case of a talar neck fracture in a skeletally immature young girl, initially missed on radiological review. However, clinical suspicion on the part of the emergency physician, repeat examination and further radiographic imaging revealed this rare paediatric injury.

  18. Clavicle Fracture (Broken Collarbone) (United States)

    ... birth canal. Symptoms Clavicle fractures can be very painful and may make it hard to move your arm. Additional symptoms include: • Sagging shoulder (down and forward) • Inability to li the arm ...

  19. Radial head fracture - aftercare (United States)

    ... begin using your elbow. You may need physical therapy if you have a severe fracture. Your doctor or physical therapist will tell you when you can start playing sports or using your elbow for other activities.

  20. Relative permeability through fractures

    Energy Technology Data Exchange (ETDEWEB)

    Diomampo, Gracel, P.


    The mechanism of two-phase flow through fractures is of importance in understanding many geologic processes. Currently, two-phase flow through fractures is still poorly understood. In this study, nitrogen-water experiments were done on both smooth and rough parallel plates to determine the governing flow mechanism for fractures and the appropriate methodology for data analysis. The experiments were done using a glass plate to allow visualization of flow. Digital video recording allowed instantaneous measurement of pressure, flow rate and saturation. Saturation was computed using image analysis techniques. The experiments showed that gas and liquid phases flow through fractures in nonuniform separate channels. The localized channels change with time as each phase path undergoes continues breaking and reforming due to invasion of the other phase. The stability of the phase paths is dependent on liquid and gas flow rate ratio. This mechanism holds true for over a range of saturation for both smooth and rough fractures. In imbibition for rough-walled fractures, another mechanism similar to wave-like flow in pipes was also observed. The data from the experiments were analyzed using Darcy's law and using the concept of friction factor and equivalent Reynold's number for two-phase flow. For both smooth- and rough-walled fractures a clear relationship between relative permeability and saturation was seen. The calculated relative permeability curves follow Corey-type behavior and can be modeled using Honarpour expressions. The sum of the relative permeabilities is not equal one, indicating phase interference. The equivalent homogeneous single-phase approach did not give satisfactory representation of flow through fractures. The graphs of experimentally derived friction factor with the modified Reynolds number do not reveal a distinctive linear relationship.

  1. Radial Head Fractures


    Jordan, Robert W.; Jones, Alistair DR.


    Background: Radial head fractures are common elbow injuries in adults and are frequently associated with additional soft tissue and bone injuries. Methods: A literature search was performed and the authors’ personal experiences are reported. Results: Mason type I fractures are treated non-operatively with splinting and early mobilisation. The management of Mason type II injuries is less clear with evidence supporting both non-operative treatment and internal fixation. The degree of intra-arti...

  2. Fracture mechanics evaluation for at typical PWR primary coolant pipe

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T. [Kansai Electric Power Company, Osaka (Japan); Shimizu, S.; Ogata, Y. [Mitsubishi Heavy Industries, Ltd., Kobe (Japan)


    For the primary coolant piping of PWRs in Japan, cast duplex stainless steel which is excellent in terms of strength, corrosion resistance, and weldability has conventionally been used. The cast duplex stainless steel contains the ferrite phase in the austenite matrix and thermal aging after long term service is known to change its material characteristics. It is considered appropriate to apply the methodology of elastic plastic fracture mechanics for an evaluation of the integrity of the primary coolant piping after thermal aging. Therefore we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secured, even when such through wall crack length is assumed to equal the fatigue crack growth length for a service period of up to 60 years.


    Energy Technology Data Exchange (ETDEWEB)

    Subhash Shah


    Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

  4. A Fracture Decoupling Experiment (United States)

    Stroujkova, A. F.; Bonner, J. L.; Leidig, M.; Ferris, A. N.; Kim, W.; Carnevale, M.; Rath, T.; Lewkowicz, J.


    Multiple observations made at the Semipalatinsk Test Site suggest that conducting nuclear tests in the fracture zones left by previous explosions results in decreased seismic amplitudes for the second nuclear tests (or "repeat shots"). Decreased seismic amplitudes reduce both the probability of detection and the seismically estimated yield of a "repeat shot". In order to define the physical mechanism responsible for the amplitude reduction and to quantify the degree of the amplitude reduction in fractured rocks, Weston Geophysical Corp., in collaboration with Columbia University's Lamont Doherty Earth Observatory, conducted a multi-phase Fracture Decoupling Experiment (FDE) in central New Hampshire. The FDE involved conducting explosions of various yields in the damage/fracture zones of previously detonated explosions. In order to quantify rock damage after the blasts we performed well logging and seismic cross-hole tomography studies of the source region. Significant seismic velocity reduction was observed around the source regions after the initial explosions. Seismic waves produced by the explosions were recorded at near-source and local seismic networks, as well as several regional stations throughout northern New England. Our analysis confirms frequency dependent seismic amplitude reduction for the repeat shots compared to the explosions in un-fractured rocks. The amplitude reduction is caused by pore closing and/or by frictional losses within the fractured media.

  5. Fatigue and fracture of fibre metal laminates

    CERN Document Server

    Alderliesten, René


    This book contributes to the field of hybrid technology, describing the current state of knowledge concerning the hybrid material concept of laminated metallic and composite sheets for primary aeronautical structural applications. It is the only book to date on fatigue and fracture of fibre metal laminates (FMLs). The first section of the book provides a general background of the FML technology, highlighting the major FML types developed and studied over the past decades in conjunction with an overview of industrial developments based on filed patents. In turn, the second section discusses the mechanical response to quasi-static loading, together with the fracture phenomena during quasi-static and cyclic loading. To consider the durability aspects related to strength justification and certification of primary aircraft structures, the third section discusses thermal aspects related to FMLs and their mechanical response to various environmental and acoustic conditions.

  6. Fracture simulation for zirconia toughened alumina microstructure

    CERN Document Server

    Kim, Kyungmok; Forest, Bernard


    Purpose - The purpose of this paper is to describe finite element modelling for fracture and fatigue behaviour of zirconia toughened alumina microstructures. Design/methodology/approach - A two-dimensional finite element model is developed with an actual $Al{_2}O{_3}$ - 10 vol% $ZrO{_2}$ microstructure. A bilinear, time-independent cohesive zone law is implemented for describing fracture behaviour of grain boundaries. Simulation conditions are similar to those found at contact between a head and a cup of hip prosthesis. Residual stresses arisen from the mismatch of thermal coefficient between grains are determined. Then, effects of a micro-void and contact stress magnitude are investigated with models containing residual stresses. For the purpose of simulating fatigue behaviour, cyclic loadings are applied to the models. Findings - Results show that crack density is gradually increased with increasing magnitude of contact stress or number of fatigue cycles. It is also identified that a micro-void brings about...

  7. Fracture in Phenolic Impregnated Carbon Ablator (United States)

    Agrawal, Parul; Chavez-Garcia, Jose; Pham, John


    This paper describes the development of a novel technique to understand the failure mechanisms inside thermal protection materials. The focus of this research is on the class of materials known as phenolic impregnated carbon ablators. It has successfully flown on the Stardust spacecraft and is the thermal protection system material chosen for the Mars Science Laboratory and SpaceX Dragon spacecraft. Although it has good thermal properties, structurally, it is a weak material. To understand failure mechanisms in carbon ablators, fracture tests were performed on FiberForm(Registered TradeMark) (precursor), virgin, and charred ablator materials. Several samples of these materials were tested to investigate failure mechanisms at a microstructural scale. Stress-strain data were obtained simultaneously to estimate the tensile strength and toughness. It was observed that cracks initiated and grew in the FiberForm when a critical stress limit was reached such that the carbon fibers separated from the binder. However, both for virgin and charred carbon ablators, crack initiation and growth occurred in the matrix (phenolic) phase. Both virgin and charred carbon ablators showed greater strength values compared with FiberForm samples, confirming that the presence of the porous matrix helps in absorbing the fracture energy.

  8. Coincidence of mandibular fractures with isolated posterior maxillary sinus fractures. (United States)

    Blatt, Sebastian; Rahimi-Nedjat, Roman; Sagheb, Keyvan; Piechowiak, Lisa; Walter, Christian; Brüllmann, Dan


    There are no data available to show whether there is a relationship between mandibular fractures and isolated fractures of the posterior and/or lateral walls of the maxillary sinus. The aim of this study was to determine whether there is a coincidence between these fracture patterns. Four hundred large volume cone beam computed tomography scans (CBCT) of patients with a fracture of the mandible between 2008 and 2013 were analyzed retrospectively. Patients with multiple midfacial fractures were excluded. The radiographic findings were correlated with epidemiological and clinical data of the patients such as gender, age, treatment methods, or complications. The most frequent fracture sites of the mandible were the jaw angle, the parasymphysis region, and the condyle. Nineteen of the 400 patients (4.75%) had an isolated fracture of the lateral and/or posterior maxillary sinus. Odds-ratio analysis revealed a high tendency for significant correlation of condylar process fractures with isolated maxillary sinus fractures. Chi-square test demonstrated a P-value near statistical significance (P=.054). No other fracture site of the mandible could be associated with an isolated fracture of the maxillary sinus. A condylar process fracture of the mandible after trauma without any further injury of the midface may be associated with an isolated fracture of the lateral and/or posterior maxillary sinus. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Polymer liquids fracture like solids

    DEFF Research Database (Denmark)

    Huang, Qian; Hassager, Ole


    While fracture in brittle solids has been studied for centuries until today, there are few studies on fracture in polymer liquids. Recent developments in experimental techniques, especially the combination of controlled filament stretching rheometry and high speed imaging, have opened new windows...... into the detailed study of fracture processes for polymer liquids. High speed imaging shows that polymer liquids fracture like solids with initiation and propagation of an edge fracture. However, remarkable features such as highly reproducible critical stress, independent appearance of multiple fractures...

  10. CT classification of acetabular fractures

    Energy Technology Data Exchange (ETDEWEB)

    Marincek, B.; Porcellini, B.; Robotti, G.


    The contribution of computed tomography (CT) in classifying acetabular fractures was analysed retrospectively in 33 cases. CT and plain radiography classification agreed in 27 cases (82%). CT revealed more extensive fractures in 6 patients (thereof 5 patients with associated fractures). In 10 patients (thereof 9 patients with associated fractures) CT showed intraarticular fragments; radiographically intraarticular fragments were seen only in 2 patients and suspected in 4. CT is of considerable aid in defining the fracture pattern. It should be used mainly in patients with radiographically difficult interpretable associated fractures in order to assess preoperatively the weight-bearing part of the acetabulum, the degree of displacement and the presence of intraarticular fragments.

  11. Thermal comfort

    CSIR Research Space (South Africa)

    Osburn, L


    Full Text Available wider range of temperature limits, saving energy while still satisfying the majority of building occupants. It is also noted that thermal comfort varies significantly between individuals and it is generally not possible to provide a thermal environment...

  12. Fracture Propagation and Permeability Change under Poro-thermoelastic Loads & Silica Reactivity in Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad Ghassemi


    /dissolution, as well as the variation in fracture aperture and pressure. Also, a three-dimensional model of injection/extraction has been developed to consider the impact poro- and thermoelastic stresses on fracture slip and injection pressure. These investigations shed light on the processes involved in the observed phenomenon of injection pressure variation (e.g., in Coso), and allow the assessment of the potential of thermal and chemical stimulation strategies.

  13. Fracture Mechanics of Concrete

    DEFF Research Database (Denmark)

    Ulfkjær, Jens Peder

    Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high-strength......Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high......-strength concrete. Chapter 2 A description of the factors which influence the strength and cracking of concrete and high strength concrete is made. Then basic linear fracture mechanics is outlined followed by a description and evaluation of the models used to describe concrete fracture in tension. The chapter ends...... to describe fracture in concrete are presented. Two of the methods are combined into a power method which is stable for all brittleness numbers and which is able of calculating the entire load-displacement curve even for very ductile beams. This method is used extensively in the rest of the thesis. Chapter 4...

  14. Pediatric calcaneal fractures

    Directory of Open Access Journals (Sweden)

    Hobie Summers


    Full Text Available Although operative treatment of displaced, intra-articular fractures of the calcaneus in adults is generally accepted as standard practice, operative treatment for the same fractures in the skeletally immature remains controversial, potentially because the outcome for fracture types (intra- vs. extra-articular and severity (displaced vs. nondisplaced have been confounded in studies of children. We review herein the results of 21 displaced, intra-articular fractures in 18 skeletally immature patients, who were treated with open reduction and internal fixation using a standard surgical approach and protocol developed for adults. The average pre-operative Böhler's angle on the injured side was -5° (range: -35 - +35 compared to 31° (range: +22 - +47 on the uninjured side, indicating substantial displacement. There were no post-operative infections or wound healing problems, and all but one patient was followed to union (average follow-up: 1.5 years; range: 0.30-4.3 years. Maintenance of reduction was confirmed on follow-up radiographs with an average Böhler's angle of 31° (range: +22 - +49. We demonstrate that results for operative fixation of displaced, intra-articular calcaneal fractures in the skeletally immature are comparable to those in adults when the treatment protocol is the same.

  15. Frontal bone fractures. (United States)

    Marinheiro, Bruno Henrique; de Medeiros, Eduardo Henrique Pantosso; Sverzut, Cássio Edvard; Trivellato, Alexandre Elias


    The aim of this retrospective study was to evaluate the epidemiology, treatment, and complications of frontal bone fractures associated, or not, with other facial fractures. This evaluation also sought to minimize the influence of the surgeon's skills and the preference for any rigid internal fixation system. The files from 3758 patients who attended the Oral and Maxillofacial Surgery Department of the School of Dentistry of Ribeirao Preto, University of Sao Paulo, from March 2004 to November 2011 and presented with facial trauma were scanned, and 52 files were chosen for the review. Eleven (21.15%) of these patients had pure fractures of the frontal bone, and trauma incidence was more prevalent in men (92.3%), whites (61.53%), and adults (50%). Despite the use of helmets at the moment of the trauma, motorcycle crashes were the most common etiological factor (32.69%). Fracture of the anterior wall of the frontal sinus with displacement was the main injury observed (54.9%), and the most common treatment was internal fixation with a plate and screws (45.09%). Postoperative complications were observed in 35.29% of the cases. The therapy applied was effective in handling this type of fracture, and the success rate was comparable to that reported in other published studies.

  16. Development of a binder fracture test to determine fracture energy. (United States)


    It has been found that binder testing methods in current specifications do not accurately predict cracking performance at intermediate temperatures. Fracture energy has been determined to be strongly correlated to fracture resistance of asphalt mixtu...

  17. Transstyloid, transscaphoid, transcapitate fracture: a variant of scaphocapitate fractures.

    LENUS (Irish Health Repository)

    Burke, Neil G


    Transstyloid, transscaphoid, transcapitate fractures are uncommon. We report the case of a 28-year-old man who sustained this fracture following direct trauma. The patient was successfully treated by open reduction internal fixation of the scaphoid and proximal capitate fragment, with a good clinical outcome at 1-year follow-up. This pattern is a new variant of scaphocapitate fracture as involves a fracture of the radial styloid as well.

  18. Foal Fractures: Osteochondral Fragmentation, Proximal Sesamoid Bone Fractures/Sesamoiditis, and Distal Phalanx Fractures. (United States)

    Reesink, Heidi L


    Foals are susceptible to many of the same types of fractures as adult horses, often secondary to external sources of trauma. In addition, some types of fractures are specific to foals and occur routinely in horses under 1 year of age. These foal-specific fractures may be due to the unique musculoskeletal properties of the developing animal and may present with distinct clinical signs. Treatment plans and prognoses are tailored specifically to young animals. Common fractures not affecting the long bones in foals are discussed in this article, including osteochondral fragmentation, proximal sesamoid bone fractures/sesamoiditis, and distal phalanx fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. DEM Particle Fracture Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Boning [Univ. of Colorado, Boulder, CO (United States); Herbold, Eric B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homel, Michael A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Regueiro, Richard A. [Univ. of Colorado, Boulder, CO (United States)


    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

  20. Geometrically Frustrated Fracture Mechanics (United States)

    Mitchell, Noah; Koning, Vinzenz; Vitelli, Vincenzo; Irvine, William T. M.


    When a flat elastic sheet is forced to conform to a surface with Gaussian curvature, stresses arise in the sheet. The mismatch between initial and final metrics gives rise to new fracture behavior which cannot be achieved by boundary loading alone. Using experiments of PDMS sheets frustrated on 3D-printed surfaces and a linearized analytical model, we demonstrate the ability of curvature to govern the sheets' fracture phenomenology. In this talk, we first show that curvature can both stimulate and suppress fracture initiation, depending on the position and orientation of the initial slit. Secondly, we show that curvature can steer the path of a crack as it propagates through the material. Lastly, the curvature can arrest cracks which would otherwise continue to propagate.

  1. open fractures - effect of infection on fracture fixation

    African Journals Online (AJOL)

    stability, soft tissue cover, union of the fracture and above all prevent infection. Therefore various methods ... Also soft tissue cover should be done as soon as possible following the fix and flap-protocal (7) for open fractures ... and flap: the radical orthopaedic and plastic treatment of severe open fractures of the tibia.

  2. Optimizing fracture prevention: the fracture liaison service, an observational study

    NARCIS (Netherlands)

    Eekman, D.A.; van Helden, S.H.; Huisman, A.M.; Verhaar, H.J.J.; Bultink, I.E.M.; Geusens, P.P.; Lips, P.T.A.M.; Lems, W.F.


    Summary: The response rate to the invitation to the fracture liaison service and reasons for non-response were evaluated in 2,207 fragility fracture patients. Fifty-one percent responded; non-responders were most often not interested (38%) or were hip fracture patients. After 1 year of treatment,

  3. Odontoid fracture biomechanics. (United States)

    Ivancic, Paul C


    In vitro biomechanical study. To investigate mechanisms of odontoid fracture. Odontoid fractures in younger adults occur most often due to high-energy trauma including motor vehicle crashes and in older adults due to fall from standing height. Horizontally aligned head impacts into a padded barrier were simulated using a human upper cervical spine specimen (occiput through C3) mounted to a surrogate torso mass on a sled and carrying a surrogate head. We divided 13 specimens into 3 groups on the basis of head impact location: upper forehead in the midline, upper lateral side of the forehead, and upper lateral side of the head. Post-impact fluoroscopy and anatomical dissection documented the injuries. Time-history biomechanical responses were determined. Four of the 5 specimens subjected to impact to the upper forehead in the midline sustained type II or high type III odontoid fractures due to abrupt deceleration of the head and continued forward torso momentum. Average peak force reached 1787.1 N at the neck at 50.3 milliseconds. Subsequently, the motion peaks occurred for the head relative to C3 reaching 15.2° for extension, 2.1 cm for upward translation, and 5.3 cm for horizontal compression, between 62 and 68 milliseconds. We identified impact to the upper forehead in the midline as a mechanism that produced odontoid fracture and associated atlas and ligamentous injuries similar to those observed in real-life trauma. We were not able to create odontoid fractures during impacts to the upper lateral side of the forehead or upper lateral side of the head. Dynamic odontoid fracture was caused by rapid deceleration of the head, which transferred load inferiorly combined with continued torso momentum, which caused spinal compression and anterior shear force and forward displacement of the axis relative to the atlas.

  4. Bilateral Femoral Neck Fracture-Related Hyperparathyroidism


    Ezirmik, Naci; Yildiz, Kadri; Cadirci, Kenan


    Bilateral femoral neck fracture is not common as unilateral femoral fracture. Femoral neck fracture generally occurs by the high energized traumas. Traffic accidents and fallings are the most common reason for this fracture kind. But suddenly and minor traumatic fractures is not common. Especially, in the hormonal and pathogenic fractures is not common. In this case minor traumatic bilateral femoral fracture is presented. The fracture occurs in the background of critical medical condition by ...

  5. Fracture After Total Hip Replacement (United States)

    ... osteolysis. Symptoms The most common symptoms of periprosthetic hip fracture include: • Pain around the hip or thigh • Swelling ... o en very painful, someone with a periprosthetic hip fracture will most likely go directly to the emergency ...

  6. [Fractures of the thumb ray]. (United States)

    Mehling, I M; Schillo, K; Arsalan-Werner, A; Seegmüller, J; Langheinrich, A C; Sauerbier, M


    Fractures of the first thumb ray are common and need accurate differential treatment to restore gripping hand functions. Displaced fractures of the distal and proximal phalanx of the thumb are often treated with screws or Kirschner wires. Stable fractures can also be treated non-operatively. Fractures of the base of the first metacarpal should be differentiated into extra-articular Winterstein fractures and intra-articular Bennett or Rolando fractures. Traction forces by the abductor pollicis longus tendon regularly lead to displacement of the shaft of the first metacarpal; therefore, these fractures usually require reduction and fixation. Good functional results can be achieved by operative treatment. Fractures of the trapezium are rare. If they are displaced, operative treatment is recommended to prevent osteoarthritis of the first carpometacarpal joint.

  7. Vertebroplasty for Spine Fracture Pain (United States)

    ... and break.How are spinal fractures treated?Most fractures of the spine are treated with bed rest until the pain goes away. Pain medicines, back braces and physical therapy may also be used. For some patients, doctors ...

  8. Pediatric Orbital Fractures (United States)

    Oppenheimer, Adam J.; Monson, Laura A.; Buchman, Steven R.


    It is wise to recall the dictum “children are not small adults” when managing pediatric orbital fractures. In a child, the craniofacial skeleton undergoes significant changes in size, shape, and proportion as it grows into maturity. Accordingly, the craniomaxillofacial surgeon must select an appropriate treatment strategy that considers both the nature of the injury and the child's stage of growth. The following review will discuss the management of pediatric orbital fractures, with an emphasis on clinically oriented anatomy and development. PMID:24436730

  9. Fractured Petroleum Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Firoozabadi, Dr. Abbas


    In this report the results of experiments of water injection in fractured porous media comprising a number of water-wet matrix blocks are reported for the first time. The blocks experience an advancing fracture-water level (FWL). Immersion-type experiments are performed for comparison; the dominant recovery mechanism changed from co-current to counter-current imbibition when the boundary conditions changed from advancing FWL to immersion-type. Single block experiments of co-current and counter-current imbibition was performed and co-current imbibition leads to more efficient recovery was found.

  10. Robotic Long Bone Fracture Reduction


    Graham, A. E.; Xie, S. Q.; Aw, K. C.; Xu, W.L.; Mukherjee, S.


    This research into a medical robot for realigning fractured bones aims to develop the interface, robot, and database technologies to improve the working situation for users and outcome for recipients. Compared with other approaches to fracture reduction, the system being developed here has a number of novel features. The geometric modeling has been effective in allowing a surgeon to visualize the fractured bone and has not been reported elsewhere for fracture reduction to the authors knowledg...


    African Journals Online (AJOL)


    Fracture of ilium, the most common fracture seen in the pelvis account for 46% of all pelvic fracture (Henry, 1985; De Camp, 2005). Whereas, acetabular fracture comprises 12 % of pelvic fractures in dogs (De Camp, 2005). In smaller dogs, most of the pelvic fractures recover without surgery. But immediate surgery is.

  12. Numerical Modeling of Fracture Propagation in Naturally Fractured Formations (United States)

    Wang, W.; Prodanovic, M.; Olson, J. E.; Schultz, R.


    Hydraulic fracturing consists of injecting fluid at high pressure and high flowrate to the wellbore for the purpose of enhancing production by generating a complex fracture network. Both tensile failure and shear failure occur during the hydraulic fracturing treatment. The shear event can be caused by slip on existing weak planes such as faults or natural fractures. From core observation, partially cemented and fully cemented opening mode natural fractures, often with considerable thickness are widely present. Hydraulic fractures can propagate either within the natural fracture (tensile failure) or along the interface between the natural fracture and the rock matrix (tensile/shear failure), depending on the relative strength of cement and rock matrix materials, the bonding strength of interface, as well as the presence of any heterogeneities. In this study, we evaluate the fracture propagation both experimentally and numerically. We embed one or multiple inclusions of different mechanical properties within synthetic hydrostone samples in order to mimic cemented natural fractures and rock. A semi-circular bending test is performed for each set of properties. A finite element model built with ABAQUS is used to mimic the semi-circular bending test and study the fracture propagation path, as well as the matrix-inclusion bonding interface status. Mechanical properties required for the numerical model are measured experimentally. The results indicate that the match between experiment and modeling fracture path are extremely sensitive to the chosen interface (bonding) model and related parameters. The semi-circular bending test is dry and easily conducted, providing a good platform for validating numerical approaches. A validated numerical model will enable us to add pressurized fluid within the crack and simulate hydraulic fracture-natural fracture interaction in the reservoir conditions, ultimately providing insights into the extent of the fracture network.

  13. On the evaluation of steam assisted gravity drainage in naturally fractured oil reservoirs

    Directory of Open Access Journals (Sweden)

    Seyed Morteza Tohidi Hosseini


    Full Text Available Steam Assisted Gravity Drainage (SAGD as a successful enhanced oil recovery (EOR process has been applied to extract heavy and extra heavy oils. Huge amount of global heavy oil resources exists in carbonate reservoirs which are mostly naturally fractured reservoirs. Unlike clastic reservoirs, few studies were carried out to determine the performance of SAGD in carbonate reservoirs. Even though SAGD is a highly promising technique, several uncertainties and unanswered questions still exist and they should be clarified for expansion of SAGD methods to world wide applications especially in naturally fractured reservoirs. In this communication, the effects of some operational and reservoir parameters on SAGD processes were investigated in a naturally fractured reservoir with oil wet rock using CMG-STARS thermal simulator. The purpose of this study was to investigate the role of fracture properties including fracture orientation, fracture spacing and fracture permeability on the SAGD performance in naturally fractured reservoirs. Moreover, one operational parameter was also studied; one new well configuration, staggered well pair was evaluated. Results indicated that fracture orientation influences steam expansion and oil production from the horizontal well pairs. It was also found that horizontal fractures have unfavorable effects on oil production, while vertical fractures increase the production rate for the horizontal well. Moreover, an increase in fracture spacing results in more oil production, because in higher fracture spacing model, steam will have more time to diffuse into matrices and heat up the entire reservoir. Furthermore, an increase in fracture permeability results in process enhancement and ultimate recovery improvement. Besides, diagonal change in the location of injection wells (staggered model increases the recovery efficiency in long-term production plan.

  14. Efficiency and accuracy of equivalent fracture models for predicting fractured geothermal reservoirs: the influence of fracture network patterns (United States)

    Chen, Tao; Clauser, Christoph; Marquart, Gabriele


    Frequently, flow and transport in fractured geothermal reservoirs are modeled using discrete and continuum fracture models. In discrete fracture models, each fracture is represented explicitly based on unstructured grids, which increases greatly the computational effort. In continuum models, e.g., equivalent fracture models, the hydraulic properties of fractures are averaged on coarse grids, which are often applied for the field-scale modeling. We use and compare both discrete and equivalent fracture models for predicting the field-scale temperature distribution in fractured geothermal reservoirs. We assess the efficiency and the accuracy of the equivalent fracture models regarding the influence of fracture network pattern: In one model fractures are parallel to the axes of the model, another one contains also non-parallel fractures. We use the OpenGeoSys and SHEMAT-Suite codes for discrete fracture modeling and for equivalent fracture modeling, respectively. For equivalent fracture modeling, both the classical finite volume scheme and the mimetic finite difference scheme are used for solving the flow equation. The Oda method is used for computing permeability for equivalent fracture models. For the non-parallel fracture network, the equivalent permeability tensor contains off-diagonal components. Our simulations show that the equivalent fracture models remain computationally efficient with changing fracture pattern. The temperature at the production well turns out to be less sensitive to fracture pattern variations compared to the discrete fracture model. And the equivalent fracture model yields efficient and accurate results in case of dominating parallel fractures.

  15. Calcaneal fractures • In children

    African Journals Online (AJOL)


    Jul 15, 1989 ... Eight patients with 9 calcaneal fractures were reviewed. Of the fractures 6 were intra-articular and 3 extra-articular but in children this distinction appears to have little relevan~e to treatment or prognosis. While these fractures are relatively uncommon in children, clinical suspicion is important in making the ...

  16. An Equivalent Fracture Modeling Method (United States)

    Li, Shaohua; Zhang, Shujuan; Yu, Gaoming; Xu, Aiyun


    3D fracture network model is built based on discrete fracture surfaces, which are simulated based on fracture length, dip, aperture, height and so on. The interesting area of Wumishan Formation of Renqiu buried hill reservoir is about 57 square kilometer and the thickness of target strata is more than 2000 meters. In addition with great fracture density, the fracture simulation and upscaling of discrete fracture network model of Wumishan Formation are very intense computing. In order to solve this problem, a method of equivalent fracture modeling is proposed. First of all, taking the fracture interpretation data obtained from imaging logging and conventional logging as the basic data, establish the reservoir level model, and then under the constraint of reservoir level model, take fault distance analysis model as the second variable, establish fracture density model by Sequential Gaussian Simulation method. Increasing the width, height and length of fracture, at the same time decreasing its density in order to keep the similar porosity and permeability after upscaling discrete fracture network model. In this way, the fracture model of whole interesting area can be built within an accepted time.

  17. Fracture Patterns Differ Between Osteogenesis Imperfecta and Routine Pediatric Fractures. (United States)

    Peddada, Kranti V; Sullivan, Brian T; Margalit, Adam; Sponseller, Paul D


    It is important to estimate the likelihood that a pediatric fracture is caused by osteogenesis imperfecta (OI), especially the least severe type of OI (type 1). We reviewed records of 29,101 pediatric patients with fractures from 2003 through 2015. We included patients with closed fractures not resulting from motor vehicle accidents, gunshot wounds, nonaccidental trauma, or bone lesions. Patients with OI of any type were identified through International Classification of Diseases-9 code. We randomly sampled 500 pediatric patients in whom OI was not diagnosed to obtain a control (non-OI) group. We reviewed age at time of fracture, sex, fracture type, laterality, and bone and bone region fractured. Bisphosphonate use and OI type were documented for OI patients. Subanalysis of patients with type-1 OI was performed. The Fisher exact and χ tests were used to compare fracture rates between groups. P<0.05 was considered significant. Positive likelihood ratios for OI were calculated by fracture pattern. The non-OI group consisted of 500 patients with 652 fractures. The OI group consisted of 52 patients with 209 fractures. Non-OI patients were older at the time of fracture (mean, 9.0±5.0 y) than OI patients (mean, 5.5±4.4 y) (P<0.001). OI patients had more oblique, transverse, diaphyseal, and bilateral long-bone fractures than non-OI patients (all P<0.001). Non-OI patients had more buckle (P=0.013), metaphyseal (P<0.001), and physeal (P<0.001) fractures than OI patients. For patients with type-1 OI and long-bone fractures (n=18), rates of transverse and buckle fractures were similar compared with controls. Transverse humerus (15.2), olecranon (13.8), and diaphyseal humerus (13.0) fractures had the highest positive likelihood ratios for OI, and physeal (0.09) and supracondylar humerus (0.1) fractures had the lowest. Transverse and diaphyseal humerus and olecranon fractures were most likely to indicate OI. Physeal and supracondylar humerus fractures were least likely

  18. Modeling thermal stress propagation during hydraulic stimulation of geothermal wells (United States)

    Jansen, Gunnar; Miller, Stephen A.


    A large fraction of the world's water and energy resources are located in naturally fractured reservoirs within the earth's crust. Depending on the lithology and tectonic history of a formation, fracture networks can range from dense and homogeneous highly fractured networks to single large scale fractures dominating the flow behavior. Understanding the dynamics of such reservoirs in terms of flow and transport is crucial to successful application of engineered geothermal systems (also known as enhanced geothermal systems or EGS) for geothermal energy production in the future. Fractured reservoirs are considered to consist of two distinct separate media, namely the fracture and matrix space respectively. Fractures are generally thin, highly conductive containing only small amounts of fluid, whereas the matrix rock provides high fluid storage but typically has much smaller permeability. Simulation of flow and transport through fractured porous media is challenging due to the high permeability contrast between the fractures and the surrounding rock matrix. However, accurate and efficient simulation of flow through a fracture network is crucial in order to understand, optimize and engineer reservoirs. It has been a research topic for several decades and is still under active research. Accurate fluid flow simulations through field-scale fractured reservoirs are still limited by the power of current computer processing units (CPU). We present an efficient implementation of the embedded discrete fracture model, which is a promising new technique in modeling the behavior of enhanced geothermal systems. An efficient coupling strategy is determined for numerical performance of the model. We provide new insight into the coupled modeling of fluid flow, heat transport of engineered geothermal reservoirs with focus on the thermal stress changes during the stimulation process. We further investigate the interplay of thermal and poro-elastic stress changes in the reservoir

  19. A numerical model of hydro-thermo-mechanical coupling in a fractured rock mass

    Energy Technology Data Exchange (ETDEWEB)

    Bower, Kathleen Marie [Univ. of New Mexico, Albuquerque, NM (United States)


    Coupled hydro-thermo-mechanical codes with the ability to model fractured materials are used for predicting groundwater flow behavior in fractured aquifers containing thermal sources. The potential applications of such a code include the analysis of groundwater behavior within a geothermal reservoir. The capability of modeling hydro-thermo systems with a dual porosity, fracture flow model has been previously developed in the finite element code, FEHM. FEHM has been modified to include stress coupling with the dual porosity feature. FEHM has been further developed to implicitly couple the dependence of fracture hydraulic conductivity on effective stress within two dimensional, saturated aquifers containing fracture systems. The cubic law for flow between parallel plates was used to model fracture permeability. The Bartin-Bandis relationship was used to determine the fracture aperture within the cubic law. The code used a Newton Raphson iteration to implicitly solve for six unknowns at each node. Results from a model of heat flow from a reservoir to the moving fluid in a single fracture compared well with analytic results. Results of a model showing the increase in fracture flow due to a single fracture opening under fluid pressure compared well with analytic results. A hot dry rock, geothermal reservoir was modeled with realistic time steps indicating that the modified FEHM code does successfully model coupled flow problems with no convergence problems.

  20. Dynamic Response and Fracture of Composite Gun Tubes

    Directory of Open Access Journals (Sweden)

    Jerome T. Tzeng


    Full Text Available The fracture behavior due to dynamic response in a composite gun tube subjected to a moving pressure has been investigated. The resonance of stress waves result in very high amplitude and frequency strains in the tube at the instant and location of pressure front passage as the velocity of the projectile approaches a critical value. The cyclic stresses can accelerate crack propagation in the gun tube with an existing imperfection and significantly shorten the fatigue life of gun tubes. The fracture mechanism induced by dynamic amplification effects is particularly critical for composite overwrap barrels because of a multi-material construction, anisotropic material properties, and the potential of thermal degradation.

  1. Boiling radial flow in fractures of varying wall porosity

    Energy Technology Data Exchange (ETDEWEB)

    Barnitt, Robb Allan


    The focus of this report is the coupling of conductive heat transfer and boiling convective heat transfer, with boiling flow in a rock fracture. A series of experiments observed differences in boiling regimes and behavior, and attempted to quantify a boiling convection coefficient. The experimental study involved boiling radial flow in a simulated fracture, bounded by a variety of materials. Nonporous and impermeable aluminum, highly porous and permeable Berea sandstone, and minimally porous and permeable graywacke from The Geysers geothermal field. On nonporous surfaces, the heat flux was not strongly coupled to injection rate into the fracture. However, for porous surfaces, heat flux, and associated values of excess temperature and a boiling convection coefficient exhibited variation with injection rate. Nucleation was shown to occur not upon the visible surface of porous materials, but a distance below the surface, within the matrix. The depth of boiling was a function of injection rate, thermal power supplied to the fracture, and the porosity and permeability of the rock. Although matrix boiling beyond fracture wall may apply only to a finite radius around the point of injection, higher values of heat flux and a boiling convection coefficient may be realized with boiling in a porous, rather than nonporous surface bounded fracture.

  2. Brittle ice shell thickness of Enceladus from fracture distribution analysis (United States)

    Lucchetti, A.; Pozzobon, R.; Mazzarini, F.; Cremonese, G.; Massironi, M.


    We determine the depth of fracture penetration in multiple regions of Enceladus by performing self-similar clustering and length distribution analysis of fractures. The statistical characterization of fault-population attribute, such as length and clustering, provide a productive avenue for exploring deformation rate, stress transmission mode, rheology of the medium, and mechanical stratification of the ice satellite. Through this analysis, we estimate the depth of the mechanical discontinuity of Enceladus' ice shell that is the depth to which fractures penetrate the brittle ice layer above the ductile one. In this work, we find that for the South Polar Terrain (SPT), the brittle ice shell interested by fracture penetration is about 30 km and corresponds to the total depth of the ice shell because the SPT has a very high thermal gradient and, hence, fractures likely reach the ocean-ice interface. In the other regions analyzed, the depth of fracture penetration increases from 31 to 70 km from the South Pole to northern regions up to 75°.

  3. Fracture mechanics and parapsychology (United States)

    Cherepanov, G. P.


    The problem of postcritical deformation of materials beyond the ultimate strength is considered a division of fracture mechanics. A simple example is used to show the relationship between this problem and parapsychology, which studies phenomena and processes where the causality principle fails. It is shown that the concept of postcritical deformation leads to problems with no solution

  4. Inclusion Requires Fracturing (United States)

    Anila, Swarupa


    Inclusion strategies and approaches in interpretive planning processes for exhibitions are often resisted because they challenge precedents in museum practice. Maintaining traditional models may seem more comfortable for many museum professionals than to do the work of closely examining, fracturing, and transforming the practices that prioritize…

  5. Colles wrist fracture - aftercare (United States)

    The initial recovery from a wrist fracture can take 3 to 4 months or more. You may need physical therapy. You should start working with a physical therapist as soon as your provider recommends. The work may seem hard and at times ...

  6. Vertebral Compression Fractures (United States)

    ... should be avoided. Steps to take after the fracture has healed include: • Chair cushions to provide support to the lower spine • Getting up out of a desk chair at least a few minutes every hour • A gradual return to exercise such as walking and/or swimming 2007; reviewed ...

  7. Neglected hangman fracture

    Directory of Open Access Journals (Sweden)

    Sudhir Kumar Srivastava


    Full Text Available Acute management of hangman fracture is well described; however the surgical management of neglected hangman fracture has not been described in literature. We report the surgical management of an untreated hangman′s fracture. A 30-year-old male had fallen from a tree 12 weeks back. Patient presented with cervical myelopathy and restricted neck movements. Radiographs and computed tomography (CT scan revealed fracture of pars interarticularis of axis with Grade III C2-C3 spondylolisthesis with localized kyphosis of 33°. Gentle reduction under general anesthesia (GA failed to improve the alignment. Patient was operated in three stages in a single setting. In Stage I, release of contracted anterior structures and C2-C3 discectomy was done in supine position followed by C2-C3 posterior fixation and fusion in Stage II. C2-C3 interbody bone grafting and anterior plating completed the third stage. C2-C3 interbody fusion was seen at 5 months and a CT scan at 18 months postoperative confirmed fusion and maintenance of alignment. The satisfactory outcome in our patient leads us to believe that anterior-posterior-anterior is the appropriate surgical approach for treatment of such patients.

  8. Pipkin Fractures: Fracture of the Head of Femur A Case Report ...

    African Journals Online (AJOL)

    Pipkin fracture is the fracture of the head of the femur. It can be associated with neck of femur fracture or / and posterior dislocation of the hip. This fracture is very rare fracture and has not been reported at our sub- region. We present this fracture in a 26 year old with a type I Pipkin fracture treated with closed reduction and ...

  9. Correlation of hip fracture with other fracture types: Toward a rational composite hip fracture endpoint. (United States)

    Colón-Emeric, Cathleen; Pieper, Carl F; Grubber, Janet; Van Scoyoc, Lynn; Schnell, Merritt L; Van Houtven, Courtney Harold; Pearson, Megan; Lafleur, Joanne; Lyles, Kenneth W; Adler, Robert A


    With ethical requirements to the enrollment of lower risk subjects, osteoporosis trials are underpowered to detect reduction in hip fractures. Different skeletal sites have different levels of fracture risk and response to treatment. We sought to identify fracture sites which cluster with hip fracture at higher than expected frequency; if these sites respond to treatment similarly, then a composite fracture endpoint could provide a better estimate of hip fracture reduction. Cohort study using Veterans Affairs and Medicare administrative data. Male Veterans (n=5,036,536) aged 50-99 years receiving VA primary care between 1999 and 2009 were included. Fractures were ascertained using ICD9 and CPT codes and classified by skeletal site. Pearson correlation coefficients, logistic regression and kappa statistics were used to describe the correlation between each fracture type and hip fracture within individuals, without regard to the timing of the events. 595,579 (11.8%) men suffered 1 or more fractures and 179,597 (3.6%) suffered 2 or more fractures during the time under study. Of those with one or more fractures, the rib was the most common site (29%), followed by spine (22%), hip (21%) and femur (20%). The fracture types most highly correlated with hip fracture were pelvic/acetabular (Pearson correlation coefficient 0.25, pfractures cluster with hip fractures within individuals at greater than expected frequency. If we observe similar treatment risk reductions within that cluster, subsequent trials could consider the use of a composite endpoint to better estimate hip fracture risk. Published by Elsevier Inc.

  10. Coupled hydro-thermo-mechanical modeling of hydraulic fracturing in quasi-brittle rocks using BPM-DEM

    Directory of Open Access Journals (Sweden)

    Ingrid Tomac


    Full Text Available This paper presents an improved understanding of coupled hydro-thermo-mechanical (HTM hydraulic fracturing of quasi-brittle rock using the bonded particle model (BPM within the discrete element method (DEM. BPM has been recently extended by the authors to account for coupled convective–conductive heat flow and transport, and to enable full hydro-thermal fluid–solid coupled modeling. The application of the work is on enhanced geothermal systems (EGSs, and hydraulic fracturing of hot dry rock (HDR is studied in terms of the impact of temperature difference between rock and a flowing fracturing fluid. Micro-mechanical investigation of temperature and fracturing fluid effects on hydraulic fracturing damage in rocks is presented. It was found that fracture is shorter with pronounced secondary microcracking along the main fracture for the case when the convective–conductive thermal heat exchange is considered. First, the convection heat exchange during low-viscosity fluid infiltration in permeable rock around the wellbore causes significant rock cooling, where a finger-like fluid infiltration was observed. Second, fluid infiltration inhibits pressure rise during pumping and delays fracture initiation and propagation. Additionally, thermal damage occurs in the whole area around the wellbore due to rock cooling and cold fluid infiltration. The size of a damaged area around the wellbore increases with decreasing fluid dynamic viscosity. Fluid and rock compressibility ratio was found to have significant effect on the fracture propagation velocity.


    Directory of Open Access Journals (Sweden)

    Đivo Ban


    Full Text Available Children and adolescents today, all before starting with regular sports activities and involvement in semi-professional and top professional sport, so it increases the num- ber of discovered stress fractures in this age. This type of injury can occur as a consequence of action one strong force, or the many repeated small force strength, to be exact, when the load (stress transcend ability reparations bones. Stress fractures are recorded and described up to the lower limbs. Research has been confirmed that the bones of lower leg are mostly made in injury, and with the el- derly and with the population of children and young adolescents. Occur in many sports, something to them is greater when the frequency of running and often are present in the female population. According to the results of numerous investigations, mistakes in the training are the most common cause of the emergence of stress fracture. In a direct comparison with complemented these injuries is the condition of muscles, so it is important that at the sa- me time carry out exercises strengthen muscles and stretching. Typical clinical signs of stress fractures are localized painful sensitivity to palpa- tion and runoff in a small number of cases. The basic diagnostic procedure is a medical check, it is the small, radiology and scintigraphyc diagnostics (most accurate and mag- netic resonance imaging. Treatment is usually without surgery and conservative, with rest and reducing stress, and its activity athlete breaks mainly between four and eight weeks. Only the very need surgical treatment The most important thing is that attention is focused on the proper prevention and to take all that it ever occurred to stress fractures that athletes ramble of the courts and the competition (better education of sports workers, separation of groups with increa- sed risk of the formation of an injury, adaptation activities age and abilities of athletes, adequate sports equipment, high-quality sports

  12. Surgical Management of Patellar Fractures. (United States)

    Kakazu, Rafael; Archdeacon, Michael T


    The patella plays a crucial role in the extensor mechanism to increase the mechanical advantage of the quadriceps. Fractures can be classified based on displacement, comminution, and fracture pattern, which often guide treatment. Modern treatment options include internal fixation using tension bands with Kirschner wires or cannulated screws, lag screw fixation, partial patellectomy, and rarely total patellectomy. Nondisplaced, closed patellar fractures or fractures with less than 2-mm articular steps can be successfully treated conservatively. Open fractures, articular step of 2 mm or greater, and loss of knee extension are indications for surgical intervention. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Fracture Phenomena in Amorphous Selenium

    DEFF Research Database (Denmark)

    Lindegaard-Andersen, Asger; Dahle, Birgit


    Fracture surfaces of amorphous selenium broken in flexure at room temperature have been studied. The fracture velocity was found to vary in different regions of the fracture surface. Peculiar features were observed in a transition zone between fast and slower fracture. In this zone cleavage steps...... with a nearly constant spacing of approximately 1 µ were found. Occasionally long cleavage whiskers—up to some millimeters long—were observed. Within certain regions the cleavage steps were crossed and interrupted by two line systems. The maximum fracture velocity has been measured to 350 m/sec. Further...

  14. [Osteoporotic fractures of the pelvis]. (United States)

    Böhme, J; Höch, A; Josten, C


    The incidence of osteoporotic pelvic fractures is rapidly increasing. Following low energy trauma fractures are frequently classified as pelvic girdle fractures. Based on the pelvic expert group database of the German Trauma Society the estimated rate of osteoporotic pelvic ring fractures is about 51%. In cases of fractured pubic rami standard X-ray in anterior-posterior, inlet and outlet views should be carried out by computed tomography (CT) scanning to identify fractures of the sacrum. Only if pain persists and no fracture is evident with CT is magnetic resonance imaging (MRI) indicated. Therapy should be carried out under biomechanical instability aspects. Pubic rami fractures are stable and treated conservatively with sufficient pain medication, thromboembolic prophylaxis and physiotherapy. In cases of persisting pain or biomechanical instability operative treatment is indicated and stabilization methods should be chosen under biomechanical aspects. Therefore external fixator for pubic rami fractures and iliosacral screws, optionally with cement augmentation for posterior pelvic girdle fractures are the preferred techniques. Sacral fractures with severe osteolysis should be stabilized by lumbopelvic fixation techniques.

  15. Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns. (United States)

    Mitov, Gergo; Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter


    The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling 5℃-55℃ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at 137℃, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns.

  16. Thermal shock testing of lapped optical glass (United States)

    Zhang, Yingrui; Wu, Yuansun; Liu, Han; Lambropoulos, John C.


    We have measured and modeled the thermal shock fracture of the commercially available BK-7 borosilicate crown optical glass as a function of surface finish prior to thermal shock testing. For surfaces lapped with alumina abrasives in the range 5 μm to 40 μm, the critical temperature drop for fracture in thin disk samples increases with diminishing abrasive size, and changes from 123.7+/-1.1 °C (for surfaces lapped with 40 μm abrasives) to 140.2+/-2.8 °C (for surfaces lapped with 5 μm abrasives.) We correlate the measured thermal shock (critical) temperature drop with the glass thermal and mechanical properties, including the fracture toughness, and the depth of surface cracks induced by the lapping process. We distinguish between "severe" and "mild" thermal shock conditions in terms of the applicable heat transfer coefficient and Biot number. We estimate that the depth of the strength controlling cracks on the edge of the disk samples was about 55-70 μm.

  17. Pelvic fractures resulting from snowboarding. (United States)

    Ogawa, Hiroyasu; Sumi, Hiroshi; Sumi, Yasuhiko; Shimizu, Katsuji


    Information regarding pelvic fractures sustained during snowboarding is scant. To analyze the epidemiologic data, injury patterns, and types of pelvic fractures sustained during snowboarding. Case series; Level of evidence, 4. We analyzed the epidemiologic factors, injury patterns, and types of pelvic fractures in 145 patients with snowboarding-related pelvic fractures who were admitted to our institution from the 1998-1999 to the 2006-2007 ski season. The incidence of snowboarding-related pelvic fractures was 0.102 per 10 000 ski lift tickets, which amounted to 2% of all snowboarding-related fractures (fifth most common type of fracture among all snowboarding-related fractures). Of the pelvic fractures, 85.5% were stable (type A according to the Tile classification) and 14.5% were unstable (types B and C according to the Tile classification). Isolated sacral fractures had the second-highest incidence (24.1%) after pubic bone and/or ischium fractures (46.9%). A distinct female prevalence was seen (52.4%). Jumps and isolated falls were the main mechanisms of injury (80%), and the incidence of collision was significantly higher in the unstable group than in the stable group (P = .037). In all, 57.9% patients classified their skill level as "intermediate," and only 9.7% of patients had received professional snowboarding lessons. A total of 30 subjects (20.8%) had other injuries along with pelvic fractures; the patients with multiple injuries were significantly more frequent in the unstable group than in the stable group (P = .035). Pelvic fractures resulting from snowboarding accidents included a higher proportion with isolated sacral fractures in the stable group and a lower prevalence of associated injuries in the unstable group compared with those resulting from other causes.

  18. Multiphysics of Fractures across Scales (United States)

    Pyrak-Nolte, L. J.


    Remote monitoring of fluid flow in fractured rock faces challenges because fractures are topologically complex, span a range of length scales, and are routinely altered due to physical and chemical processes. A long-standing goal has been to find a link between fluid flow supported by a fracture and the seismic response of that fracture. This link requires a relationship between intrinsic fracture properties and macroscopic scattered wave fields. Furthermore, such a link among multiphysical properties of fracture should be retained as the scale of observation changes. Recently, Pyrak-Nolte and Nolte (Nature Comm., 2016) demonstrated, numerically, that a scaling relationship exists between fluid flow and fracture specific stiffness, linked through the topology of the fracture void geometry (i.e. fracture void space and contact area spatial distributions). This scaling relationship holds for fractures with either random or spatially correlated aperture distributions. To extend these results, a heuristic numerical study was performed to determine if fracture specific stiffness determined from seismic wave attenuation (defined through a displacement-discontinuity boundary condition) corresponds to static stiffness based on deformation measurements. In the long wavelength limit, static and dynamic stiffness are closely connected. As the scattering conditions of the fracture move out of the long-wavelength limit, a frequency-dependent stiffness is defined that captures low-order corrections, extending the regime of applicability of the displacement discontinuity model. The displacement discontinuity theory has a built-in scaling parameter that ensures some set of discontinuities will be optimal for detection as different wavelengths sample different subsets of fractures. Future studies will extend these concepts to fracture networks. Acknowledgments: The U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences

  19. Thermophysical properties of selected powders for thermal barrier coatings


    M. Drajewicz; M. Góral; M. Pytel; J. Sieniawski


    Purpose: Plasma-sprayed thermal barrier coatings often have the problems of spallation and cracking in service owing to their poor bond strength and high residual stresses. Functionally graded thermal barrier coatings with a gradual compositional variation from heat resistant ceramics to fracture-resistant metals are proposed to mitigate these problems.Design/methodology/approach: The results of measurements of thermal diffusivity by using one of the most modern experimental sets LFA 427 (Las...

  20. A fracture prevention service reduces further fractures two years after incident minimal trauma fracture. (United States)

    Van der Kallen, John; Giles, Michelle; Cooper, Kerry; Gill, Kerry; Parker, Vicki; Tembo, Agness; Major, Gabor; Ross, Linda; Carter, Jan


    To evaluate the impact of a fracture prevention clinic service on initiation of treatment, continuing treatment and subsequent minimal trauma fractures (MTF). Participants were people aged 50 and over, with a minimal trauma fracture presenting to the Emergency Department (ED) in a large tertiary referral hospital in New South Wales, Australia, between February 2007 and March 2009. A cohort of patients who attended a Fracture Prevention Clinic (clinic group) were compared with a cohort who did not attend the clinic (non-clinic group). A telephone questionnaire was conducted with participants or their carers between December 2010 and April 2011 at least 12 months post-fracture presentation. Questionnaire items included demographics, fracture types, osteoporosis treatment, recurrent fractures and smoking and dietary habits. Data were compared using chi-squared test for categorical variables and Student's t-test or Mann-Whitney U-test for continuous variables. Two hundred and fourteen clinic attendees and 220 non-clinic attendees were surveyed between 12 and 40 months (mean 24 months) post-initial fracture. New fracture rates were lower in the clinic group (5.1%) than the non-clinic group (16.4%, P fracture prevention clinic service following a MTF have fewer new fractures and are more likely to be on treatment for bone fragility. © 2013 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.


    Directory of Open Access Journals (Sweden)

    Deepak Kaladagi


    Full Text Available BACKGROUND: The incidence of humeral fracture has significantly increased during the present years due to the population growth and road traffic, domestic, industrial, automobile accidents & disasters like tsunami, earthquakes, head-on collisions, polytrauma etc. In order to achieve a stable fixation followed by early mobilization, numerous surgical implants have been devised. PURPOSE: The purpose of this study is to analyze the results of intramedullary fixation of proximal 2/3rd humeral shaft fractures using an unreamed interlocking intramedullary nail. INTRODUCTION: In 40 skeletally matured patients with fracture shaft of humerus admitted in our hospital, we used unreamed antegrade interlocking nails. MATERIAL: We carried out a prospective analysis of 40 patients randomly selected between 2001 to 2014 who were operated at JNMC Belgaum, MMC Mysore & Navodaya Medical College, Raichur. All cases were either RTAs, Domestic, Industrial, automobile accidents & also other modes of injury. METHOD: Routine investigations with pre-anaesthetic check-up & good quality X-rays of both sides of humerus was taken. Time of surgery ranged from 5-10 days from the time of admission. Only upper 1/3rd & middle 1/3rd humeral shaft fractures were included in the study. In all the cases antegrade locked unreamed humeral nails were inserted under C-arm. Patient was placed in supine position & the shoulder was kept elevated by placing a sandbag under the scapula. In all patients incision taken from tip of acromion to 3cm over deltoid longitudinally. Postoperatively sling applied with wrist & shoulder movements started after 24 hours. All the patients ranged between the age of 21-50 years. RESULTS: Total 40 patients were operated. Maximum fracture site were in the middle third- 76%, 14% upper 1/3rd. All 40 patients achieved union. The average time of union was 8-10 weeks. All patients regained full range of movements except in few cases, where there was shoulder

  2. Fracture of brittle solids

    CERN Document Server

    Lawn, Brian


    This is an advanced text for higher degree materials science students and researchers concerned with the strength of highly brittle covalent-ionic solids, principally ceramics. It is a reconstructed and greatly expanded edition of a book first published in 1975. The book presents a unified continuum, microstructural and atomistic treatment of modern day fracture mechanics from a materials perspective. Particular attention is directed to the basic elements of bonding and microstructure that govern the intrinsic toughness of ceramics. These elements hold the key to the future of ceramics as high-technology materials--to make brittle solids strong, we must first understand what makes them weak. The underlying theme of the book is the fundamental Griffith energy-balance concept of crack propagation. The early chapters develop fracture mechanics from the traditional continuum perspective, with attention to linear and nonlinear crack-tip fields, equilibrium and non-equilibrium crack states. It then describes the at...

  3. Fracture Networks in Sea Ice

    Directory of Open Access Journals (Sweden)

    Jonas Nesland Vevatne


    Full Text Available Fracturing and refreezing of sea ice in the Kara sea are investigated using complex networkanalysis. By going to the dual network, where the fractures are nodes and their intersectionslinks, we gain access to topological features which are easy to measure and hence comparewith modeled networks. Resulting network reveal statistical properties of the fracturing process.The dual networks have a broad degree distribution, with a scale-free tail, high clusteringand efficiency. The degree-degree correlation profile shows disassortative behavior, indicatingpreferential growth. This implies that long, dominating fractures appear earlier than shorterfractures, and that the short fractures which are created later tend to connect to the longfractures.The knowledge of the fracturing process is used to construct growing fracture network (GFNmodel which provides insight into the generation of fracture networks. The GFN model isprimarily based on the observation that fractures in sea ice are likely to end when hitting existingfractures. Based on an investigation of which fractures survive over time, a simple model forrefreezing is also added to the GFN model, and the model is analyzed and compared to the realnetworks.

  4. Double segmental tibial fractures - an unusual fracture pattern

    Directory of Open Access Journals (Sweden)

    Bali Kamal


    Full Text Available 【Abstract】A case of a 50-year-old pedestrian who was hit by a bike and suffered fractures of both bones of his right leg was presented. Complete clinical and radiographic assessment showed double segmental fractures of the tibia and multisegmental fractures of the fibula. Review of the literature revealed that this fracture pattern was unique and only a single case was reported so far. Moreover, we discussed the possible mechanisms which can lead to such an injury. We also discussed the management of segmental tibial fracture and the difficulties encountered with them. This case was managed by modern osteosynthesis tech- nique with a pleasing outcome. Key words: Fracture, bone; Tibia; Fibula; Nails

  5. Phase Field Fracture Mechanics.

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Brett Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.

  6. Osteoporosis, Fractures, and Diabetes


    Peter Jackuliak; Juraj Payer


    It is well established that osteoporosis and diabetes are prevalent diseases with significant associated morbidity and mortality. Patients with diabetes mellitus have an increased risk of bone fractures. In type 1 diabetes, the risk is increased by ∼6 times and is due to low bone mass. Despite increased bone mineral density (BMD), in patients with type 2 diabetes the risk is increased (which is about twice the risk in the general population) due to the inferior quality of bone. Bone fragility...

  7. Atypical femoral fractures


    Giannini, Sandro; Chiarello, Eugenio; Tedesco, Giuseppe; Cadossi, Matteo; Luciani, Deianira; Mazzotti, Antonio; Donati, Davide Maria


    Bisphosphonates (BPs) represent the most widely used therapy for osteoporosis. Recently, a relationship between long-term treatment with BPs and a subset of atypical femoral fractures (AFFs) from below the lesser trochanter to the sovracondilar line has been described. Many etiopathogenetic theories have been invoked to explain AFFs: reduced bone turnover and increased osteoblast bone apposition with accumulation of microdamage and decreased bone toughness with subsequent increased risk of mi...

  8. Radial Head Fractures (United States)

    Jordan, Robert W.; Jones, Alistair DR.


    Background: Radial head fractures are common elbow injuries in adults and are frequently associated with additional soft tissue and bone injuries. Methods: A literature search was performed and the authors’ personal experiences are reported. Results: Mason type I fractures are treated non-operatively with splinting and early mobilisation. The management of Mason type II injuries is less clear with evidence supporting both non-operative treatment and internal fixation. The degree of intra-articular displacement and angulation acceptable for non-operative management has yet to be conclusively defined. Similarly the treatment of type III and IV fractures remain controversial. Traditional radial head excision is associated with valgus instability and should be considered only for patients with low functional demands. Comparative studies have shown improved results from internal fixation over excision. Internal fixation should only be attempted when anatomic reduction and initiation of early motion can be achieved. Authors have reported that results from fixation are poorer and complication rates are higher if more than three fragments are present. Radial head arthroplasty aims to reconstruct the native head and is indicated when internal fixation is not feasible and in the presence of complex elbow injuries. Overstuffing of the radiocapitellar joint is a frequent technical fault and has significant adverse effects on elbow biomechanics. Modular design improves the surgeon’s ability to reconstruct the native joint. Two randomised controlled trials have shown improved clinical outcomes and lower complication rate following arthroplasty when compared to internal fixation. Conclusion: We have presented details regarding the treatment of various types of radial head fractures - further evidence, however, is still required to provide clarity over the role of these different management strategies. PMID:29290880

  9. Cricket related maxillofacial fractures. (United States)

    Lee, Kai


    Cricket is a popular sport in New Zealand, enjoyed both at social and competitive level. Although it is a non-contact sport and there is in place good facial protection, injury to the head and neck region is still frequently seen in the emergency department. Data were collected from departmental records between 1996 and 2006. Variables examined included incidence, demographics, site of fracture and treatment method. Of the 561 patients with sports-related maxillofacial fractures during the study period, 40 were cricket-related. Male to female ratio was 36:1. 45% of patients were in the 16-30 year age group. 55% of injuries were due to impact from cricket ball. 70% of injuries occurred at midface level, while 30% at the mandible. 38% of patients required surgery and hospitalization. Maxillofacial fracture from cricket playing is a frequent injury in patients presenting with sports-related injuries. Cricket players need to be educated on the safety measures in playing the sport, including facial protection devices.

  10. Conceptual evaluation of the potential role of fractures in unsaturated processes at Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, Jennifer J.; Bodvarsson, Gudmundur S.; Nieder-Westermann, Gerald H.


    A wide array of field observations, in situ testing, and rock and water sampling (and subsequent analyses) within the unsaturated zone of Yucca Mountain demonstrate the importance of fractures to flow and transport in the welded tuffs. The abundance of fractures and the spatial variability in their hydraulic properties, along with the heterogeneity within lithologic formations, make evaluation of unsaturated processes occurring within the potential repository horizon complex. Fracture mapping and field testing show that fractures are well connected, yet considerable variation is seen within and between units comprising the potential repository horizon with regard to fracture trace length, spacing, permeability, and capillarity. These variations have important implications for the distribution and movement of water and solutes through the unsaturated zone. Numerical models designed to assess such phenomena as unsaturated flow, transport, and coupled thermal-hydrological processes each require their own conceptual model for fracture networks, in order to identify the subset of all fractures that is relevant to the particular study. We evaluate several process-dependent conceptual models for fractures and identify the relevant fracture subsets related to these processes.

  11. Geology and fracture system at Stripa. Technical information report No. 21

    Energy Technology Data Exchange (ETDEWEB)

    Olkiewicz, A.; Gale, J.E.; Thorpe, R.; Paulsson, B.


    The Stripa test site has been excavated in granitic rock between 338 m and 360 m below the ground surface, and is located under the north limb of an ENE-plunging synclinal structure. The granitic rocks, in the areas mapped, are of Archean age and are dominated by a reddish, medium-grained, massive monzogranite that shows varying degrees of deformation. The granitic rocks have been intruded by diabase (dolerite) and pegmatite dikes. Surface and subsurface mapping shows that the Stripa granite is highly fractured and that there are at least four joint sets in the area of the test excavations. In addition to the joints, the rock mass contains fissures, fracture zones, and small-scale shear zones, representing the complete spectrum of the fracture family. Most of the fractures are lined with chlorite, occasionally with calcite. Many of the small-scale shear fractures are filled or coated with epidote. Offsets of pegmatite dikes formed by these fractures are usually limited to one to two meters. Water seepage is observed only as drops from fractures or moist fracture surfaces. It was found that reconstruction of the local three-dimensional fracture system is the heater-experiment sites was difficult, and in some cases subjective. Such reconstruction is a prerequisite to accurate interpretation of thermal and mechanical data from such sites.

  12. Evaluation of five fracture models in Taylor impact fracture (United States)

    Zhang, Wei; Xiao, Xin-Ke; Wei, Gang; Guo, Zitao


    Taylor impact test presented in a previous study on a commercial high strength and super hard aluminum alloy 7A04-T6 are numerically evaluated using the finite element code ABAQUS/Explicit. In the present study, the influence of fracture criterion in numerical simulations of the deformation and fracture behavior of Taylor rod has been studied. Included in the paper are a modified version of Johnson-Cook, the Cockcroft-Latham(C-L), the constant fracture strain, the maximum shear stress and the maximum principle stress fracture models. Model constants for each criterion are calibrated from material tests. The modified version of Johnson-Cook fracture criterion with the stress triaxiality cut off idea is found to give good prediction of the Taylor impact fracture behavior. However, this study will also show that the C-L fracture criterion where only one simple material test is required for calibration is found to give reasonable predictions. Unfortunately, the other three criteria are not able to repeat the experimentally obtained fracture behavior. The study indicates that the stress triaxiality cut off idea is necessary to predict the Taylor impact fracture.

  13. Database for hydraulically conductive fractures

    Energy Technology Data Exchange (ETDEWEB)

    Tammisto, E.; Palmen, J.; Ahokas, H. (Poeyry Environment Oy, Vantaa (Finland))


    Posiva flow logging (PFL) with a 0.5 m test interval and made in 10 cm steps can be used for the determination of the depth of hydraulically conductive fractures. Together with drillhole wall images and fracture data from core logging, PFL provides possibilities to detect individual conductive fractures. In this report, the results of PFL are combined with fracture data on drillholes OL-KR1 - OL-KR40, OL-KR15B - KR20B, OL-KR22B - KR23B, OL-KR25B, OL-KR27B, OL-KR29B, OL-KR31B, OLKR33B, OL-KR37B and OL-KR39B - KR40B and pilot holes OL-PH1 and ONK-PH2 - ONK-PH7. The conductive fractures were first recognised from PFL data and digital drillhole images and then the fractures from the core logging that correspond to the ones picked from the digital drillhole images were identified. The conductive fractures were primarily recognised in the images based on the openness of fractures or a visible flow in the image. In most of the cases, no tails of flow were seen in the image. In these cases the conductive fractures were recognised in the image based on the openness of fractures and a matching depth. On the basis of the results hydraulically conductive fractures/zones could in most cases be distinguished in the drillhole wall images. An important phase in the work is the calibration of the depth of the image and flow logging with the sample length. Hydraulic conductivity is clearly higher in the upper part of the bedrock in the depth range 0-150 m below sea level than deeper in the bedrock. The frequency of hydraulically conductive fractures (T > 10-10-10-9 m2/s) in depth range 0-150 m varies between 0.06 and 0.78 fractures/metre of sample length. Deeper in the rock conductive fractures are less frequent, but often occur in groups of a few fractures. About 10% of the conductive fractures are within HZ-structures and 6% within BFZ-structures. 3% of the conductive fractures are within HZ- and BFZ-structures. (orig.)

  14. Characterisation of fracture network and groundwater preferential ...

    African Journals Online (AJOL)

    Characterisation of fractured rocks and evaluation of fracture connectivity are essential for the study of subsurface flow and transport in fractured rock aquifers. In this study, we use a new method to present fracture networks and analyse the connectivity of the fractures, based on the technique of randomly-generated ...

  15. [Patella fractures in knee arthroplasty]. (United States)

    Roth, A; Ghanem, M; Fakler, J


    Periprosthetic patella fractures occur both with and without retropatellar joint replacement. A non-operative treatment yields satisfactory results with low morbidity. It can be applied in minimally displaced fractures that have an intact retropatellar component and an intact extensor mechanism, combined with an initial immobilization. The surgical treatment is associated with relatively poor results and with high complication rates. There was only minor improvement of functional results, no matter which surgical technique was used. Surgical intervention is still required in fractures with a loosening of the patellar component, considerable dislocations of fragments, and damage to or rupture of the extensor mechanism. In particular, type II fractures require repair of the extensor mechanism and the fracture or patellectomy. Type III fractures require a revision or resection of the patella, a patelloplasty or total patellectomy. In addition, early or late reconstruction using allograft to restore the extensor mechanism can be taken in consideration.

  16. Fracture healing: mechanisms and interventions (United States)

    Einhorn, Thomas A.; Gerstenfeld, Louis C.


    Fractures are the most common large-organ, traumatic injuries to humans. The repair of bone fractures is a postnatal regenerative process that recapitulates many of the ontological events of embryonic skeletal development. Although fracture repair usually restores the damaged skeletal organ to its pre-injury cellular composition, structure and biomechanical function, about 10% of fractures will not heal normally. This article reviews the developmental progression of fracture healing at the tissue, cellular and molecular levels. Innate and adaptive immune processes are discussed as a component of the injury response, as are environmental factors, such as the extent of injury to the bone and surrounding tissue, fixation and the contribution of vascular tissues. We also present strategies for fracture treatment that have been tested in animal models and in clinical trials or case series. The biophysical and biological basis of the molecular actions of various therapeutic approaches, including recombinant human bone morphogenetic proteins and parathyroid hormone therapy, are also discussed. PMID:25266456

  17. Complex Fluids and Hydraulic Fracturing. (United States)

    Barbati, Alexander C; Desroches, Jean; Robisson, Agathe; McKinley, Gareth H


    Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fluids are used: naturally occurring polysaccharide and synthetic polymer solutions, aqueous physical and chemical gels, organic gels, micellar surfactant solutions, emulsions, and foams. These fluids are loaded over a wide range of concentrations with particles of varying sizes and aspect ratios and are subjected to extreme mechanical and environmental conditions. We describe the settings of hydraulic fracturing (framed by geology), fracturing mechanics and physics, and the critical role that non-Newtonian fluid dynamics and complex fluids play in the hydraulic fracturing process.

  18. Gene Therapy for Fracture Repair (United States)


    forma - tion and finally remodeling [8]. Fracture callus formation eventually results in the bridging of the fracture and the restoration of skeletal...analysis was performed using ImaGene software (BioDiscovery, El Segundo, CA), that used an internal statistical analysis of the signal intensity of...expression during the normal repair of a simple femur fracture with the elimination of scar tissue from the healing bone. This model does not address

  19. Effect of particle size on fracture toughness of SiC/Al composite material (United States)

    Flom, Y.; Arsenault, R. J.


    Discontinuous SiC/Al composites with SiC particles of different sizes were fabricated in order to study the role of particle size on the fracture process. The fracture process is confined to a very narrow band and takes place within the matrix in composites containing small SiC particle sizes. In the composite reinforced with SiC particles of 20 microns and above fracture of SiC begins to dominate. The matrix is influenced by the high density of dislocations generated at SiC/Al interfaces due to the difference in coefficient of thermal expansion between SiC and the Al matrix. Crack initiation fracture toughness does not depend on SiC particle size. Crack growth fracture toughness increases as the size of the SiC particle increase.

  20. Modelling fracture in ferritic steel

    CERN Document Server

    Smith, G


    Results from mathematical models and computer simulations of fracture in polycrystalline steels are presented for a range of temperatures. The proportions of intergranular and intragranular failure predicted are compared with experimental results for brittle fracture, ductile fracture and in the transition region. Interactive software to create two-dimensional polycrystalline models, which allow a range of physical to be varied independently, is described. The results include those for model materials chosen to match steels used by the power generation industry. The models simulate segregation and cavitation effects in steel and fracture of weldments and their associated heat-affected zones.

  1. Easily missed thoracolumbar spine fractures

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Mark [NYU Langone Medical Center/Bellevue Hospital, 550 1st Avenue, IRM-234, New York, NY 10016 (United States)], E-mail:


    Thoracolumbar spine fractures are common and can be difficult to diagnose. Many of these fractures are associated with extraspinal injuries and are subtle on imaging further contributing to diagnostic delay or misdiagnosis. Missed fractures are associated with increased neurologic injury and resulting morbidity. Careful and thorough workup of the multitrauma patient with dedicated spinal imaging is necessary to identify these injuries. This article reviews the major thoracolumbar spine fractures and imaging findings with attention drawn to subtle and easily overlooked features of these injuries.

  2. Tracer-based prediction of thermal reservoir lifetime: scope, limitations, and the role of thermosensitive tracers (United States)

    Ghergut, I.; Behrens, H.; Karmakar, S.; Licha, T.; Nottebohm, M.; Sauter, M.


    Thermal-lifetime prediction is a traditional endeavour of inter-well tracer tests conducted in geothermal reservoirs. Early tracer test signals (detectable within the first few years of operation) are expected to correlate with late-time production temperature evolutions ('thermal breakthrough', supposed to not occur before some decades of operation) of a geothermal reservoir. Whenever a geothermal reservoir can be described as a single-fracture system, its thermal lifetime will, ideally, be determined by two parameters (say, fracture aperture and porosity), whose inversion from conservative-tracer test signals is straightforward and non-ambiguous (provided that the tracer tests, and their interpretation, are performed in accordance to the rules of the art). However, as soon as only 'few more' fractures are considered, this clear-cut correlation is broken. A given geothermal reservoir can simultaneously feature a single-fracture behaviour, in terms of heat transport, and a multiple-fracture behaviour, in terms of solute tracer transport (or vice-versa), whose effective values of fracture apertures, spacings, and porosities are essentially uncorrelated between heat and solute tracers. Solute transport parameters derived from conservative-tracer tests will no longer characterize the heat transport processes (and thus temperature evolutions) taking place in the same reservoir. Parameters determining its thermal lifetime will remain 'invisible' to conservative tracers in inter-well tests. We demonstrate this issue at the example of a five-fracture system, representing a deep-geothermal reservoir, with well-doublet placement inducing fluid flow 'obliquely' to the fractures. Thermal breakthrough in this system is found to strongly depend on fracture apertures, whereas conservative-solute tracer signals from inter-well tests in the same system do not show a clear-cut correlation with fracture apertures. Only by using thermosensitive substances as tracers, a reliable

  3. Development of high-thermal-conductivity silicon nitride ceramics

    Directory of Open Access Journals (Sweden)

    You Zhou


    Full Text Available Silicon nitride (Si3N4 with high thermal conductivity has emerged as one of the most promising substrate materials for the next-generation power devices. This paper gives an overview on recent developments in preparing high-thermal-conductivity Si3N4 by a sintering of reaction-bonded silicon nitride (SRBSN method. Due to the reduction of lattice oxygen content, the SRBSN ceramics could attain substantially higher thermal conductivities than the Si3N4 ceramics prepared by the conventional gas-pressure sintering of silicon nitride (SSN method. Thermal conductivity could further be improved through increasing the β/α phase ratio during nitridation and enhancing grain growth during post-sintering. Studies on fracture resistance behaviors of the SRBSN ceramics revealed that they possessed high fracture toughness and exhibited obvious R-curve behaviors. Using the SRBSN method, a Si3N4 with a record-high thermal conductivity of 177 Wm−1K−1 and a fracture toughness of 11.2 MPa m1/2 was developed. Studies on the influences of two typical metallic impurity elements, Fe and Al, on thermal conductivities of the SRBSN ceramics revealed that the tolerable content limits for the two impurities were different. While 1 wt% of impurity Fe hardly degraded thermal conductivity, only 0.01 wt% of Al caused large decrease in thermal conductivity.

  4. Cracking behavior of tungsten armor under ELM-like thermal shock loads: A computational study

    National Research Council Canada - National Science Library

    Li, Muyuan; Werner, Ewald; You, Jeong-Ha


    In this work, the cracking behavior of tungsten under edge-localized mode (ELM)-like thermal shock loads was investigated on the basis of a rigorous computational fracture mechanical analysis combined with the finite element method...

  5. Influence of micro-structural parameters and thermal cycling on the ...

    Indian Academy of Sciences (India)

    Keywords. Ultra high performance fibre reinforced cement-based composite; CARDIFRC; micro-structure; mechanical and fracture properties; thermal cycling. ... Author Affiliations. B L Karihaloo1. School of Engineering, Cardiff University, Cardiff, UK ...

  6. Characterisation of hydraulically-active fractures in a fractured ...

    African Journals Online (AJOL)

    ... in the initial stage of a site investigation to select the optimal site location or to evaluate the hydrogeological properties of fractures in underground exploration studies, such as those related geothermal reservoir evaluation and radioactive waste disposal. Keywords: self-potential method, hydraulically-conductive fractures, ...

  7. Distal radius fractures in the athlete

    National Research Council Canada - National Science Library

    Beleckas, Casey; Calfee, Ryan


    Distal radius fractures are one of the most common upper extremity fractures. Athletes with distal radius fractures are treated according to the same principles as non-athletes but present several unique considerations...

  8. Zoledronic acid and clinical fractures and mortality after hip fracture

    DEFF Research Database (Denmark)

    Lyles, Kenneth W; Colón-Emeric, Cathleen S; Magaziner, Jay S


    BACKGROUND: Mortality is increased after a hip fracture, and strategies that improve outcomes are needed. METHODS: In this randomized, double-blind, placebo-controlled trial, 1065 patients were assigned to receive yearly intravenous zoledronic acid (at a dose of 5 mg), and 1062 patients were...... assigned to receive placebo. The infusions were first administered within 90 days after surgical repair of a hip fracture. All patients (mean age, 74.5 years) received supplemental vitamin D and calcium. The median follow-up was 1.9 years. The primary end point was a new clinical fracture. RESULTS...... in the two groups. CONCLUSIONS: An annual infusion of zoledronic acid within 90 days after repair of a low-trauma hip fracture was associated with a reduction in the rate of new clinical fractures and with improved survival. ( number, NCT00046254 [].)....

  9. Fracture patterns at lava-ice contacts on Kokostick Butte, OR, and Mazama Ridge, Mount Rainier, WA: Implications for flow emplacement and cooling histories (United States)

    Lodge, Robert W. D.; Lescinsky, David T.


    Cooling lava commonly develop polygonal joints that form equant hexagonal columns. Such fractures are formed by thermal contraction resulting in an isotropic tensional stress regime. However, certain linear cooling fracture patterns observed at some lava-ice contacts do not appear to fit the model for formation of cooling fractures and columns because of their preferred orientations. These fracture types include sheet-like (ladder-like rectangular fracture pattern), intermediate (pseudo-aligned individual column-bounding fractures), and pseudopillow (straight to arcuate fractures with perpendicular secondary fractures caused by water infiltration) fractures that form the edges of multiple columns along a single linear fracture. Despite the relatively common occurrence of these types of fractures at lava-ice contacts, their significance and mode of formation have not been fully explored. This study investigates the stress regimes responsible for producing these unique fractures and their significance for interpreting cooling histories at lava-ice contacts. Data was collected at Kokostick Butte dacite flow at South Sister, OR, and Mazama Ridge andesite flow at Mount Rainier, WA. Both of these lava flows have been interpreted as being emplaced into contact with ice and linear fracture types have been observed on their ice-contacted margins. Two different mechanisms are proposed for the formation of linear fracture networks. One possible mechanism for the formation of linear fracture patterns is marginal bulging. Melting of confining ice walls will create voids into which flowing lava can deform resulting in margin-parallel tension causing margin-perpendicular fractures. If viewed from the ice-wall, these fractures would be steeply dipping, linear fractures. Another possible mechanism for the formation of linear fracture types is gravitational settling. Pure shear during compression and settling can result in a tensional environment with similar consequences as

  10. Factors affecting the thermal shock behavior of yttria stabilized hafnia based graphite and tungsten composites. (United States)

    Lineback, L. D.; Manning, C. R.


    Hafnia-based composites containing either graphite or tungsten were investigated as rocket nozzle throat inserts in solid propellant rocket engines. The thermal shock resistance of these materials is considered in terms of macroscopic thermal conductivity, thermal expansion, modulus of elasticity, and compressive fracture stress. The effect of degree of hafnia stabilization, density, and graphite or tungsten content upon these parameters is discussed. The variation of the ratio of elastic modulus to compressive fracture stress with density and its effect upon thermal shock resistance of these materials are discussed in detail.

  11. Isolated Transverse Sacrum Fracture: A Case Report

    Directory of Open Access Journals (Sweden)

    Cemil Kavalci


    Full Text Available Sacral fracture commonly results from high-energy trauma. Most insufficiency fractures of the sacrum are seen in women after the age of 70. Fractures of the sacrum are rare and generally combined with a concomitant pelvic fracture. Transverse sacral fractures are even less frequent which constitute only 3–5% of all sacral fractures. This type of fractures provide a diagnostic challenge. We report a unique case of isolated transverse fracture of sacrum in a young man sustained low-energy trauma. The patient presented to our emergency department after several hours of injury, and diagnosed by clinical features and roentgenogram findings.

  12. Arthroscopy-assisted fracture fixation. (United States)

    Atesok, Kivanc; Doral, M Nedim; Whipple, Terry; Mann, Gideon; Mei-Dan, Omer; Atay, O Ahmet; Beer, Yiftah; Lowe, Joseph; Soudry, Michael; Schemitsch, Emil H


    the purpose of this article was to systematically analyze the results of published studies in the literature which evaluated the use of arthroscopically assisted techniques in intra-articular fracture fixation. published investigations to date were analyzed by classifying them according to joints that were involved with intra-articular fractures including: knee, ankle, hip, shoulder, elbow, and wrist joints. The results were studied to assess the feasibility, efficiency, and outcomes of arthroscopy-assisted fracture fixation. arthroscopy-assisted techniques have been used successfully for the treatment of fractures of the tibial plateau, tibial eminence, malleoli, pilon, calcaneus, femoral head, glenoid, greater tuberosity, distal clavicle, radial head, coronoid, distal radius, and scaphoid. The major advantages of arthroscopic fracture fixation over open methods are direct visualization of the intra-articular space, decreased invasiveness, and the possibility for multitask interventions through which fixation of the fracture, and repair of the soft tissues and the cartilage can be performed simultaneously. The time-consuming and technically demanding nature of the procedures with a prolonged learning curve and limited fixation alternatives are the main disadvantages of this technique. arthroscopic fixation is increasingly utilized for certain intra-articular fracture types due to the minimally invasive nature of the procedures and high accuracy. Randomized controlled trials are needed to justify wider use of arthroscopy-assisted techniques for treatment of intra-articular fractures.

  13. Epidemiological study on talus fractures. (United States)

    Sakaki, Marcos Hideyo; Saito, Guilherme Honda; de Oliveira, Rafael Garcia; Ortiz, Rafael Trevisan; Silva, Jorge Dos Santos; Fernandes, Túlio Diniz; Dos Santos, Alexandre Leme Godoy


    to analyze the characteristics of patients with talus fractures and the injuries that they present. retrospective analysis on patients hospitalized in the Institute of Orthopedics and Traumatology, Hospital das Clínicas, School of Medicine of the University of São Paulo, between 2006 and 2011, with talus fractures. Patient profile parameters, risk factors, fracture characteristics, treatment data and acute complications were analyzed. analysis on 23 cases showed that men were more affected than women, with a ratio of 4.8:1. The most frequent trauma mechanism was traffic accidents, followed by falls from a height. The most frequent type of fracture was at the neck of the talus, with 17 cases. Among the 23 cases, seven had peritalar dislocation at the time of presentation, four had exposed fractures and 11 presented other associated fractures. The mean length of time between the trauma and the definitive treatment was six days, while the mean length of hospital stay was 11 days. Three patients presented acute postoperative complications. talus fractures occurred most commonly in the region of the talar neck and most frequently in young males who suffered high-energy trauma. In almost half of the cases, there were other associated fractures. The length of hospital stay was 11 days.

  14. Interpersonal violence and facial fractures. (United States)

    Lee, Kai H


    Interpersonal violence is a major health hazard that contributes to the high volume of trauma seen in the emergency department. It is also one of the principal causes of maxillofacial fractures. The present study was a retrospective analysis of patients referred to, and treated at, the Oral and Maxillofacial Surgery Unit at Christchurch Hospital during an 11-year period (1996 to 2006). The variables examined included patient demographics, fracture types, mode of injury, and treatment delivered. An increase was found in the number of fractures due to interpersonal violence in the second half of the study, although the proportion remained the same. The age of the patients ranged from 9 to 89 years (mean 28). The male-to-female ratio was 9:1. Of the patients, 87% had alcohol involvement. The mandible was the most common site of fracture, followed by the zygoma. Other midface fractures, including Le Fort fractures, were less frequently observed. Of the patients, 59% were hospitalized and 56% required surgery, with internal fixation necessary in 41% of patients. An increase occurred in the number of facial fractures associated with interpersonal violence during the study period. Young male adults were the most affected demographic group, with alcohol a main contributing factor. Violence-related facial fracture is a health hazard that deserves more public awareness and implementation of preventive programs.

  15. Arthroplasty for Femoral Neck Fractures

    NARCIS (Netherlands)

    P.T.P.W. Burgers (Paul)


    markdownabstractThe aim of this thesis is threefold. The first aim is to study the cumulative incidence of bilateral femoral neck fractures and the use of two types of arthroplasty for these fractures. The second aim is to investigate the reliability and validity of the Western Ontario and

  16. Bilateral acetabular fracture without trauma


    Rosa, M. A.; Maccauro, G.; D’Arienzo, M.


     In the absence of trauma fracture of the acetabulum is an extremely rare injury. We describe a 70 year old man who spontaneously developed fractures in both acetabulae due to bony insufficiency. It was successfully treated by bilateral total hip replacement.

  17. [Surgical treatment of unstable pelvic fractures combined with acetabular fractures]. (United States)

    Wang, Tao; Wang, Jun; Li, Zong-yuan; Liu, Gang


    To discuss the treatment strategy of acetabular fractures and unstable pelvic fracture of the hip and to evaluate its outcome. Retrospective analysis of clinical data in 32 patients with unstable pelvic fracture and acetabular fractures from January 2007 to June 2013 were collected. There were 18 males and 14 females aged from 18 to 62 years old (means 38 years old). According to Tile classification of pelvic fracture, 11 cases were type B1, 8 were type B2.1, 7 were type B2.2, 3 were type C1.1, 2 were type C1.2, 1 was type C3. According to Judet-Letournel classification, anterior column fracture was in 1 case, transverse fracture in 8, transverse plus posterior wall fracture in 6, T-type fracture in 1, anterior column plus half transverse fractures in 5, double column fracture in 11. Other combined injuries were treated early, the surgical operation were performed after stable condition. The hip joint function and the fracture reduction were assessed during follow-up. The operative time was from 1.8 to 6.5 hours (averaged 3 hours). Two fat patients' incision occurred in fat liquefaction and healed after dressing, no incision infection happened. Only 1 case was lost to follow-up, 31 patients were followed up with a mean time of 23 months (6 to 42 months). The healing time of pelvic fracture was from 8 to 18 weeks (averaged in 10.6 weeks). The hip function was evaluated according to the Matta and Tornetta standard postoperatively, the result was excellent in 15 cases, good in 14 cases, fair and poor in 1 case respectively. The Majeed score of the hip function was 83.65? 7.67, the result was excellent in 15 cases, good in 12 cases and fair in 4 cases. The healing time of acetabular fractures was from 8 to 16 weeks (averaged in 10.2 weeks). The fracture reduction was assessed by Matta standard, the result was excellent in 15 cases, good in 12 cases and fair in 4 cases. The heterotopic ossification was evaluated by Brooker standard, 4 cases were grade I, 1 case was

  18. Numerical Analysis on the Formation of Fracture Network during the Hydraulic Fracturing of Shale with Pre-Existing Fractures

    Directory of Open Access Journals (Sweden)

    Jianming He


    Full Text Available In this paper, configurations of pre-existing fractures in cubic rock blocks were investigated and reconstructed for the modeling of experimental hydraulic fracturing. The fluid-rock coupling process of hydraulic fracturing was simulated based on the displacement discontinuities method. The numerical model was validated against the related laboratory experiments. The stimulated fracture configurations under different conditions can be clearly shown using the validated numerical model. First, a dominated fracture along the maximum principle stress direction is always formed when the stress difference is large enough. Second, there are less reopened pre-existing fractures, more newly formed fractures and less shear fractures with the increase of the cohesion value of pre-existing fractures. Third, the length of the stimulated shear fracture decreases rapidly with the increase of the friction coefficient, while the length of the tensile fracture has no correlation to the fiction coefficient. Finally, the increase of the fluid injection rate is favorable to the formation of a fracture network. The unfavorable effects of the large stress difference and the large cohesion of pre-existing fractures can be partly suppressed by an increase of the injection rate in the hydraulic fracturing treatment. The results of this paper are useful for understanding fracture propagation behaviors during the hydraulic fracturing of shale reservoirs with pre-existing fractures.

  19. [Mandibular fracture in an infant]. (United States)

    Alberth, M; Szilágyi, Z; Póti, S; Redl, P


    Maxillofacial fractures under 10 years of age are uncommon, with an occurrence of 7.3%. Isolated fractures of the mandible are even more rare, due to the fact that in young children the mandible is relatively small and resilient. Some authors suggest that the occurrence of this form of fracture is about 1-5%. Different methods have been described for treatment of fractures off the mandible in children. In the therapy since the introduction of titanium mini plates the trend has been to select surgical repositioning followed by osteosynthesis. This paper describes the management of a 7-month old boy with isolated mandibular fracture, using this method to avoid the damage of the tooth germs. This particular case raises the issue of child abuse, which is on the increase in Hungary as well. To find a kind of solution would be not only a task of dentists but also of society in general.

  20. Fractures of the proximal humerus

    DEFF Research Database (Denmark)

    Brorson, Stig


    . The bandages were further supported by splints made of wood or coarse grass. Healing was expected in forty days. Different fracture patterns have been discussed and classified since Ancient Greece. Current classification of proximal humeral fractures mainly relies on the classifications proposed by Charles......, classification of proximal humeral fractures remains a challenge for the conduct, reporting, and interpretation of clinical trials. The evidence for the benefits of surgery in complex fractures of the proximal humerus is weak. In three systematic reviews I studied the outcome after locking plate osteosynthesis......Fractures of the proximal humerus have been diagnosed and managed since the earliest known surgical texts. For more than four millennia the preferred treatment was forceful traction, closed reduction, and immobilization with linen soaked in combinations of oil, honey, alum, wine, or cerate...

  1. Distal clavicle fractures in children

    Directory of Open Access Journals (Sweden)

    Pedro José Labronici


    Full Text Available ABSTRACT OBJECTIVE: To analyze fractures of the distal clavicle region in pediatric patients. METHODS: Ten patients between the ages of five to eleven years (mean of 7.3 years were observed. Nine patients were treated conservatively and one surgically. All the fractures were classified using the Nenopoulos classification system. RESULTS: All the fractures consolidated without complications. Conservative treatment was used for nine patients, of whom three were in group IIIB, three IIb, two IIa and one IV. The only patient who was treated surgically was a female patient of eleven years of age with a group IV fracture. CONCLUSION: The treatment indication for distal fractures of the clavicle in children should be based on the patient's age and the displacement of the fragments.

  2. Flexible fixation and fracture healing

    DEFF Research Database (Denmark)

    Schmal, Hagen; Strohm, Peter C; Jaeger, Martin


    , noncomminuted fractures. External fixation uses external bars for stabilization, whereas internal fixation is realized by subcutaneous placement of locking plates. Both of these "biologic" osteosynthesis methods allow a minimally invasive approach and do not compromise fracture hematoma and periosteal blood...... of articular fractures. They allow for subchondral stabilization using small-diameter angular stable screws as well as buttressing of the joint and the metaphyseal component of a fracture. Biomechanically, they can be far stiffer than external fixators, because subcutaneous plates are located much closer...... to the bone surface than external fixator bars. External fixators have the advantage of being less expensive, highly flexible, and technically less demanding. They remain an integral part of orthopaedic surgery for emergent stabilization, for pediatric fractures, for definitive osteosynthesis in certain...

  3. Collagen turnover after tibial fractures

    DEFF Research Database (Denmark)

    Joerring, S; Krogsgaard, M; Wilbek, H


    Collagen turnover after tibial fractures was examined in 16 patients with fracture of the tibial diaphysis and in 8 patients with fracture in the tibial condyle area by measuring sequential changes in serological markers of turnover of types I and III collagen for up to 26 weeks after fracture....... The markers were the carboxy-terminal extension peptide of type I procollagen (PICP), the amino-terminal extension peptide of type III procollagen (PIIINP), and the pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP). The latter is a new serum marker of degradation of type I...... collagen. A group comparison showed characteristic sequential changes in the turnover of types I and III collagen in fractures of the tibial diaphysis and tibial condyles. The turnover of type III collagen reached a maximum after 2 weeks in both groups. The synthesis of type I collagen reached a maximum...

  4. Distal clavicle fractures in children☆ (United States)

    Labronici, Pedro José; da Silva, Ricardo Rodrigues; Franco, Marcos Vinícius Viana; Labronici, Gustavo José; Pires, Robinson Esteves Santos; Franco, José Sergio


    Objective To analyze fractures of the distal clavicle region in pediatric patients. Methods Ten patients between the ages of five to eleven years (mean of 7.3 years) were observed. Nine patients were treated conservatively and one surgically. All the fractures were classified using the Nenopoulos classification system. Results All the fractures consolidated without complications. Conservative treatment was used for nine patients, of whom three were in group IIIB, three IIb, two IIa and one IV. The only patient who was treated surgically was a female patient of eleven years of age with a group IV fracture. Conclusion The treatment indication for distal fractures of the clavicle in children should be based on the patient's age and the displacement of the fragments. PMID:26962489

  5. Radiographic evaluation of maxillofacial fractures

    Energy Technology Data Exchange (ETDEWEB)

    Litwan, M.; Fliegel, C.


    The course and configuration of typical maxillofacial fractures (type Le Fort I-III) and lateral maxillary fractures including the zygomatic arch were reconstructed in detail by application of barium paste on a bony skull and radiogrpahs in standard projections were performed and evaluated. It was obvious from the resulting radiographs that for most maxillofacial fractures a half axial or Water's view was most helpful. Lateral views only give additional information when there is a considerable degree of dislocation of fragments. Comparison with a prediatric skull of 8 years of age demonstrated that fractures of the zygomatic arch in this age group cannot be demonstrated by the typical submento-vertical view, but are shown on a Towne projection. The radiographic appearance of important maxillofacial fractures is demonstrated. The necessity of further studies in cases where reconstructive surgery appears necessary is discussed and CT rather then conventional tomography is advocated.

  6. Fractures of the femoral neck. (United States)

    Kyle, Richard F


    Fractures of the femoral neck are increasing at an exponential rate as a result of the longevity of the general population. The Garden and Pauwels classifications both are routinely used to describe displacement and stability of femoral neck fractures. Osteonecrosis and nonunion remain problematic because of the compromised blood supply to the femoral head in displaced fractures. Nondisplaced fractures and displaced fractures in patients physiologically younger than 65 years are treated with closed or open reduction and internal fixation. Anatomic reduction is the single most important step in the treatment and fixation of these difficult fractures. Because of the higher complication rate in patients physiologically older than 65 years, a prosthetic replacement may be considered for the treatment of displaced fractures. In patients who are low-level community ambulators or nursing home ambulators with comorbidities and who are not expected to live more than 5 years after injury, a hemiprosthesis is indicated. In active, elderly patients physiologically older than 65 years who are expected to live longer than 5 years after injury, a total hip replacement is the treatment of choice. Total hip replacement relieves pain and allows faster rehabilitation than other forms of treatment in this age group. Patients with preexisting hip disease also are treated with total hip replacement. An algorithm that considers physiologic age and activity level of the patient is helpful when deciding whether to fix or replace the hip in a patient with a displaced femoral neck fracture. It is also useful in deciding what type of prosthesis to use. The treatment of femoral neck fractures remains complex and difficult. Because of the enormous burden of this injury, orthopaedists must improve results in the care of femoral neck fractures.

  7. Fracture toughness of graphite composites

    Energy Technology Data Exchange (ETDEWEB)

    Blikstad, M.


    The first two papers in the thesis deal with moisture absorption in graphite/epoxy materials. Both one- and three-dimensional moisture absoption were studied. The diffusion along the fiber direction was measured. A great difference was found between the diffusion along the fiber direction and the diffusion perpendicular to the fiber direction. The experimental results were compared with three-dimensional calculations based on Fick's second law of diffusion. Edge delamination is the main subject of the next two papers. Angle-ply specimens with standard and toughened resin were loaded in tension before and after moisture absorption to obtain the fracture toughness for edge delamination. The mode of loading for inherent cracks along the edge in these types of specimens is essentially a combination of mode I and Mode III. The delamination fracture surfaces were studied in a scanning electron microscope (SEM). They exhibited hackle formation and the tilt of the hackles was found to be characteristic of the state of stress in the interlaminar region. The obtained fracture toughnesses were analyzed according to the geometrical fracture criterion. Change to a more ductile epoxy resin increased the fracture toughness. In the fifth paper the fracture toughness of ply cracking was measured in unidirectional off-axis and rail shear test specimens. By varying the off-axis angle the mode of loading was varied from pure mode I to nearly mode II. The rail shear test gave pure mode II loading. The fracture surfaces were investigated in a SEM. The obtained fracture toughness was analyzed according to the quadratic mixed mode fracture criterion. Moisturizatio of the standard resin laminate and change to a more ductile epoxy resin increased the fracture toughness. However, when the toughened resin laminate had absorbed moisture, its toughness decreased substantially.

  8. Thermal comfort

    DEFF Research Database (Denmark)

    d’Ambrosio Alfano, Francesca Romana; Olesen, Bjarne W.; Palella, Boris Igor


    Thermal comfort is one of the most important aspects of the indoor environmental quality due to its effects on well-being, people's performance and building energy requirements. Its attainment is not an easy task requiring advanced design and operation of building and HVAC systems, taking...... under specific conditions. At operation level, only few variables are taken into account with unpredictable effects on the assessment of comfort indices. In this paper, the main criteria for the design and assessment of thermal comfort are discussed in order to help building and HVAC systems designers...... into account all parameters involved. Even though thermal comfort fundamentals are consolidated topics for more than forty years, often designers seem to ignore or apply them in a wrong way. Design input values from standards are often considered as universal values rather than recommended values to be used...

  9. Fine characterization rock thermal damage by acoustic emission technique (United States)

    Kong, Biao; Li, Zenghua; Wang, Enyuan


    This paper examines the differences in the thermal mechanical properties and acoustic emission (AE) characteristics during the deformation and fracture of rock under the action of continuous heating and after high-temperature treatment. Using AE 3D positioning technology, the development and evolution of the internal thermal cracks and the time domain of AE signals in rock were analyzed. High-temperature treatment causes thermal damage to rock. Under the action of continuous heating, the phase characteristics of AE time series correspond to the five stages of rock thermal deformation and fracture, respectively: the micro-defect development stage, the threshold interval of rock micro-cracks, the crack initiation stage, the crack propagation stage, and the crack multistage propagation evolution. When the initial crack propagates, the crack initiation of the rock causes the AE signal to produce a sudden mutation change. Mechanical fraction characteristics during rock uniaxial compression after temperature treatment indicated that the decrease rate of the rock compressive strength, wave velocity, and elastic modulus are relatively large during uniaxial compression tests after high-temperature treatment. During the deformation and fracture of rock under loading, there is faster growth of AE counts and AE events, indicating an increase in the speed of rock deformation and fracture under loading. AE counts show obvious changes during the latter loading stages, whereas AE events show obvious changes during the loading process. The results obtained are valuable for rock thermal stability detection and evaluation in actual underground engineering.

  10. LNG cascading damage study. Volume I, fracture testing report.

    Energy Technology Data Exchange (ETDEWEB)

    Petti, Jason P.; Kalan, Robert J.


    As part of the liquefied natural gas (LNG) Cascading Damage Study, a series of structural tests were conducted to investigate the thermal induced fracture of steel plate structures. The thermal stresses were achieved by applying liquid nitrogen (LN{sub 2}) onto sections of each steel plate. In addition to inducing large thermal stresses, the lowering of the steel temperature simultaneously reduced the fracture toughness. Liquid nitrogen was used as a surrogate for LNG due to safety concerns and since the temperature of LN{sub 2} is similar (-190 C) to LNG (-161 C). The use of LN{sub 2} ensured that the tests could achieve cryogenic temperatures in the range an actual vessel would encounter during a LNG spill. There were four phases to this test series. Phase I was the initial exploratory stage, which was used to develop the testing process. In the Phase II series of tests, larger plates were used and tested until fracture. The plate sizes ranged from 4 ft square pieces to 6 ft square sections with thicknesses from 1/4 inches to 3/4 inches. This phase investigated the cooling rates on larger plates and the effect of different notch geometries (stress concentrations used to initiate brittle fracture). Phase II was divided into two sections, Phase II-A and Phase II-B. Phase II-A used standard A36 steel, while Phase II-B used marine grade steels. In Phase III, the test structures were significantly larger, in the range of 12 ft by 12 ft by 3 ft high. These structures were designed with more complex geometries to include features similar to those on LNG vessels. The final test phase, Phase IV, investigated differences in the heat transfer (cooling rates) between LNG and LN{sub 2}. All of the tests conducted in this study are used in subsequent parts of the LNG Cascading Damage Study, specifically the computational analyses.

  11. Clavicle fractures: epidemiology, classification and treatment of 2 422 fractures in the Swedish Fracture Register; an observational study. (United States)

    Kihlström, Caroline; Möller, Michael; Lönn, Katarina; Wolf, Olof


    Large multi-centre studies of clavicle fractures have so far been missing. The aim of this observational study was to describe the epidemiology, classification and treatment of clavicle fractures in the The Swedish Fracture Register (SFR) that collects national prospective data from large fracture populations. Data were retrieved from the SFR on all clavicle fractures sustained by patients ≥ 15 years of age in 2013-2014 (n = 2 422) with regards to date of injury, cause of injury, fracture classification and treatment. Sixty-eight per cent of the clavicle fractures occurred in males. The largest subgroup was males aged 15-24 years, representing 21% of clavicle fractures. At the ages of 65 years and above, females sustained more clavicle fractures than males. Same-level falls and bicycle accidents were the most common injury mechanisms. Displaced midshaft fractures constituted 43% of all fractures and were the most frequently operated fractures. Seventeen per cent of the patients underwent operative treatment within 30 days of the injury, where plate fixation was the choice of treatment in 94% of fractures. The largest patient group was young males. Displaced midshaft fractures were the most common type of clavicle fracture as well as the most frequently operated type of fracture.

  12. Thermal defoliation (United States)

    The negative perception some consumers hold regarding agricultural chemicals has resulted in an increased demand for organic foods and fibers, and in increasing political pressure for the regulation of agricultural production practices. This has revived interest in thermal defoliation of cotton and ...

  13. Holographic thermalization

    NARCIS (Netherlands)

    Balasubramanian, V.; Bernamonti, A.; de Boer, J.; Copland, N.; Craps, B.; Keski-Vakkuri, E.; Müller, B.; Schäfer, A.; Shigemori, M.; Staessens, W.


    Using the AdS/CFT correspondence, we probe the scale-dependence of thermalization in strongly coupled field theories following a quench, via calculations of two-point functions, Wilson loops and entanglement entropy in d=2,3,4. In the saddlepoint approximation these probes are computed in AdS space

  14. Facial Fracture-Associated Blindness. (United States)

    Béogo, Rasmané; Coulibaly, Toua Antoine; Dolo, Mariam Traoré; Traoré, Ibraima; Ouattara, Balla; Diallo, Jean Wenceslas


    Yet uncommon, blindness is a potential associated injury of facial fractures. Epidemiology, mechanisms, fracture types, and outcome of facial fractures-associated blindness in a 10-year period are retrospectively reviewed. Out of 907 facial fractures patients, 10 had blindness, giving a frequency of 1.1%. There were 9 men and 1 woman whom age range was 6 to 59 years (mean: 31.2 years). Intentional injury patients were significantly the most at risk of blindness (P = 0.02). In all the patients, the fracture involved at least 1 of the orbit walls. Risk of blindness was significantly higher in naso-fronto-orbito-ethmoidal complex fractures (P = 0.03). The vision loss was recorded in 13 eyes (unilateral in 7 patients and bilateral in 3). Its predominant mechanism was a globe rupture or perforation, recorded in 8 eyes. A treatment with intention to improve the vision was attempted in 1 patient only. None of the patients had vision recovery. The findings of this study commend comprehensive ophthalmologic evaluation in any patient with an orbit wall fracture.

  15. Early history of scapular fractures. (United States)

    Bartoníček, Jan; Kozánek, Michal; Jupiter, Jesse B


    The first to use the term Scapula was Vesalius (1514-1564) and thus it has remained ever since. Probably the oldest injured scapula, from 250 million years ago, was described by Chinese authors of a skeletal examination of a fossilised remains of a dinosaur Yangchuanosaurus hepingensis. In humans, the oldest known scapular fractures date back to the prehistoric and early historic times. In ancient times, a fracture of acromion was described in the treatises of Hippocrates. Early modern history of the treatment of scapular fractures is closely interlinked with the history of the French surgery. The first to point out the existence of these fractures were Petit, Du Verney and Desault in the 18th century. The first study devoted solely to scapular fractures was published by Traugott Karl August Vogt in 1799. Thomas Callaway published in 1849 an extensive dissertation on injuries to the shoulder girdle, in which he discussed a number of cases known at that time. The first radiograph of a scapular fracture was published by Petty in 1907. Mayo Robson (1884), Lambotte (1913) and Lane (1914) were pioneers in the surgical treatment of these fractures, followed in 1923 by the French surgeons Lenormat, Dujarrier and Basset. The first internal fixation of the glenoid fossa, including a radiograph, was published by Fischer in 1939.

  16. Spontaneous bilateral fracture of patella. (United States)

    Moretti, Biagio; Speciale, Domenico; Garofalo, Raffaele; Moretti, Lorenzo; Patella, Silvio; Patella, Vittorio


    Bilateral patellae fractures represent a rare entity, accounting for approximately 2.9% of all lesions interesting in this anatomical district. In most cases found in the published work, they are described as stress fractures or as complications of chronic diseases such as osteoporosis, renal failure and secondary hyperparathyroidism. Although many pathogenetic mechanisms have been supposed, none have been proved for certain. Insufficiency fractures of the patellae are rare events and no data has been published on their incidence. We present a case of bilateral fracture of the patellae due to an indirect trauma occurring in an 85-year-old patient affected by Parkinson's disease, osteoporosis and diffuse degenerative osteoarthritis. X-ray of the knees (anteroposterior and lateral) and magnetic resonance imaging evaluation confirmed the fractures. The patient was treated conservatively. She had a good result, returning to her previous autonomous ambulation. This case is unusual because there was no direct trauma to the knees because of bilaterality, but confirmed previous observations about insufficiency fractures of patellae in the presence of comorbidity. Insufficiency fractures of patellae can be an insidious condition in elderly people. Prepatellar pain, a common symptom in the relapse phase of degenerative arthritis of the knee, should not be underestimated, particularly in patients with diseases influencing metabolism of bone and with an elevated risk of fall. A periodical clinical and instrumental follow up should be done in these patient. Moreover, we underline the necessity of a multidisciplinary approach.

  17. Stress Fractures: Concepts and Therapeutics. (United States)

    Moreira, Carolina A; Bilezikian, John P


    Stress fractures are repetitive use injuries in which recurrent strains lead to material fatigue and microarchitectural discontinuities. They account for up to 20% of athletic injuries, more often in women and in the setting of track-and-field events. In women, menstrual disturbances, low body mass index, low energy intake, and sometimes low bone mass, may be contributing factors. There are no standard protocols for evaluation or management of stress fractures. Available literature published in English was retrieved using the following terms: stress fractures; fractures; osteoporosis, athletes, premenopausal women, and athletic triad; through PubMed. Reviews, original reports, and case reports were all included. Despite lack of consistency among the publications, a phenotype emerges, namely of individuals whose bone mineral density is reduced along with low intake of dietary calcium and low circulating levels of 25-hydroxy vitamin D. Limited experience suggests that calcium and vitamin D supplementation might be helpful. Bisphosphonates or teriparatide may accelerate fracture healing in special circumstances. Most individuals who experience a stress fracture are young and healthy and do not appear to have an underlying metabolic bone disease. On the other hand, the presence of low bone mass and hormonal disturbances in some afflicted individuals might identify a cohort who needs endocrinological attention. Prospective, well-designed studies of stress fractures are needed to elucidate further underlying pathophysiological elements that predispose such individuals. Guidelines for prevention and treatment may follow from such well-controlled studies.

  18. Gradient effects on the fracture of inhomogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Terrence Lee [Univ. of California, Berkeley, CA (United States)


    Functionally Graded Materials (FGMs) have a spatial variation in physical properties that can be tailored to meet the needs of a specific application and/or to minimize internal stresses arising from thermal and elastic mismatch. Modeling these materials as inhomogeneous continua allows assessment of the role of the gradient without requiring detailed knowledge of the microstructure. Motivated by the relative difficulty of obtaining analytical solutions to boundary value problems for FGMs, an accurate finite-element code is developed for obtaining numerical planar and axisymmetric linear thermoelastic solutions. In addition an approximate analytical technique for mapping homogeneous-modulus solutions to those for FGMs is assessed and classes of problems to which it applies accurately are identified. The fracture mechanics analysis of FGMs can be characterized by the classic stress intensities, KI and KII, but there has been scarce progress in understanding the role of the modulus gradient in determining fracture initiation and propagation. To address this question, a statistical fracture model is used to correlate near-tip stresses with brittle fracture initiation behavior. This describes the behavior of a material experiencing fracture initiation away from the crack tip. Widely dispersed zones of fracture initiation sites are expected. Finite-length kinks are analyzed to describe the crack path for continuous crack growth. For kink lengths much shorter than the gradient dimension, a parallel stress term describes the deviation of the kinking angle from that for homogeneous materials. For longer kinks there is a divergence of the kink angle predicted by the maximum energy release rate and the pure opening mode criteria.

  19. Possible factors for ankle fractures

    Directory of Open Access Journals (Sweden)

    Tabaković Dejan


    Full Text Available Background/Aim. Classification of ankle fractures is commonly used for selecting an appropriate treatment and prognosing an outcome of definite management. One of the most used classifications is the Danis-Weber classification. To the best of our knowledge, in the available literature, there are no parameters affecting specific types of ankle fractures according to the Danis-Weber classification. The aim of this study was to analyze the correlation of the following parameters: age, body weight, body mass index (BMI, height, osteoporosis, osteopenia and physical exercises with specific types of ankle fractures using the Danis-Weber classification. Methods. A total of 85 patients grouped by the Danis-Weber classification fracture types were analyzed and the significance of certain parameters for specific types of ankle fractures was established. Results. The proportion of females was significantly higher (p < 0.001 with a significantly higher age (59.9 years, SD ± 14.2 in relation to males (45.1 years, SD ± 12.8 (p < 0.0001. Type A fracture was most frequent in the younger patients (34.2 years, SD ± 8.6, and those with increased physical exercises (p = 0.020. In type B fracture, the risk factor was osteoporosis (p = 0.0180, while in type C fracture, body weight (p = 0.017 and osteoporosis (p = 0.004 were significant parameters. Conclusion. Statistical analysis using the Danis-Weber classification reveals that there are certain parameters suggesting significant risk factors for specific types of ankle fractures.

  20. Thermal Hardware for the Thermal Analyst (United States)

    Steinfeld, David


    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Space Flight Center (GSFC) Thermal Engineering Branch (Code 545). NCTS 21070-1. Most Thermal analysts do not have a good background into the hardware which thermally controls the spacecraft they design. SINDA and Thermal Desktop models are nice, but knowing how this applies to the actual thermal hardware (heaters, thermostats, thermistors, MLI blanketing, optical coatings, etc...) is just as important. The course will delve into the thermal hardware and their application techniques on actual spacecraft. Knowledge of how thermal hardware is used and applied will make a thermal analyst a better engineer.

  1. Parallel, Multigrid Finite Element Simulator for Fractured/Faulted and Other Complex Reservoirs based on Common Component Architecture (CCA)

    Energy Technology Data Exchange (ETDEWEB)

    Milind Deo; Chung-Kan Huang; Huabing Wang


    Black-oil, compositional and thermal simulators have been developed to address different physical processes in reservoir simulation. A number of different types of discretization methods have also been proposed to address issues related to representing the complex reservoir geometry. These methods are more significant for fractured reservoirs where the geometry can be particularly challenging. In this project, a general modular framework for reservoir simulation was developed, wherein the physical models were efficiently decoupled from the discretization methods. This made it possible to couple any discretization method with different physical models. Oil characterization methods are becoming increasingly sophisticated, and it is possible to construct geologically constrained models of faulted/fractured reservoirs. Discrete Fracture Network (DFN) simulation provides the option of performing multiphase calculations on spatially explicit, geologically feasible fracture sets. Multiphase DFN simulations of and sensitivity studies on a wide variety of fracture networks created using fracture creation/simulation programs was undertaken in the first part of this project. This involved creating interfaces to seamlessly convert the fracture characterization information into simulator input, grid the complex geometry, perform the simulations, and analyze and visualize results. Benchmarking and comparison with conventional simulators was also a component of this work. After demonstration of the fact that multiphase simulations can be carried out on complex fracture networks, quantitative effects of the heterogeneity of fracture properties were evaluated. Reservoirs are populated with fractures of several different scales and properties. A multiscale fracture modeling study was undertaken and the effects of heterogeneity and storage on water displacement dynamics in fractured basements were investigated. In gravity-dominated systems, more oil could be recovered at a given pore

  2. Fracture Union in Closed Interlocking Nail in Humeral Shaft Fractures

    Directory of Open Access Journals (Sweden)

    Ramji Lal Sahu


    Conclusions: The results of the present study indicates that in the presence of proper indications, reamed antegrade intramedullary interlocked nailing appears to be a method of choice for internal fixation of osteoporotic and pathologic fractures.

  3. Absolute Versus Relative Fracture Fixation: Impact on Fracture Healing. (United States)

    Norris, Brent L; Lang, Gerald; Russell, Thomas A Toney; Rothberg, David L; Ricci, William M; Borrelli, Joseph


    The goals of all orthopaedic surgeons treating fractures are, and will remain, obtaining union of the fracture with a well-aligned and functional limb while minimizing the risk of complications. This requires us to understand how the biomechanical environment of the fracture affects healing and to be able to discern which mechanical environment is preferred over another. Understanding the spectrum of stability imparted by our current surgical devices is paramount to giving our patients the best opportunity to heal and recover from their injury. Gone are the simplistic views of plates and screws being applied for absolute stability and nails and external fixators being applied for relative stability. This review sheds new light on how the use of different implants provides the appropriate stability to encourage fracture healing and limit the risk of complication and loss of function.

  4. Zoledronic acid and clinical fractures and mortality after hip fracture

    DEFF Research Database (Denmark)

    Lyles, Kenneth W; Colón-Emeric, Cathleen S; Magaziner, Jay S


    receiving zoledronic acid were pyrexia, myalgia, and bone and musculoskeletal pain. No cases of osteonecrosis of the jaw were reported, and no adverse effects on the healing of fractures were noted. The rates of renal and cardiovascular adverse events, including atrial fibrillation and stroke, were similar......BACKGROUND: Mortality is increased after a hip fracture, and strategies that improve outcomes are needed. METHODS: In this randomized, double-blind, placebo-controlled trial, 1065 patients were assigned to receive yearly intravenous zoledronic acid (at a dose of 5 mg), and 1062 patients were...... assigned to receive placebo. The infusions were first administered within 90 days after surgical repair of a hip fracture. All patients (mean age, 74.5 years) received supplemental vitamin D and calcium. The median follow-up was 1.9 years. The primary end point was a new clinical fracture. RESULTS...

  5. A Segmental Fracture of Humerus with Ipsilateral Forearm Fracture

    Directory of Open Access Journals (Sweden)

    Ruban Raj Joshi


    Full Text Available Introduction: Simultaneous segmental humerus fracture with ipsilateral forearm is an uncommon injury and scarcely mentioned in the literature. Case report: We present a case report on such a complex injury in a 9-year old child after falling down from the first floor of his house while playing. The injury pattern consist of ipsilateral supracondylar fracture humerus with distal humerus  and ipsilateral distal forearm fracture. Open reduction and pinning of the both injuries was obtained. Conclusion: Ipsilateral multiple fractures in children often result from high energy trauma and are associated with complications. Immediate reduction and fixation is required. If satisfactory reduction cannot be achieved by closed technique, open reduction should be considered to avert additional soft tissue injury and forthcoming complications.

  6. Sternal fractures and their management

    Directory of Open Access Journals (Sweden)

    Al-achraf Khoriati


    Full Text Available Sternal fractures are predominantly associated with deceleration injuries and blunt anterior chest trauma. Sternal trauma must be carefully evaluated by monitoring of vital parameters and it is of paramount importance that concomitant injuries are excluded. Nevertheless, routine admission of patients with isolated sternal fractures for observation is still common in today′s practice, which is often unnecessary. This article aims to describe the prognosis, the recommended assessment and management of patients with sternal fractures, to help clinicians make an evidence-based judgment regarding the need for hospitalization.

  7. Method for hydraulically fracturing strata

    Energy Technology Data Exchange (ETDEWEB)

    Petryashin, L.F.; Zheltoukhov, V.V.


    The proposed method for the hydraulic fracture of strata involves the input of ground magnesium and an inert substance in the bore hole, the latter being pumped under pressure into the strata. In order to improve the quality of the fracture, crystallized chloroacetic acid is used. This acid, prior to its injection into the bore hole, is mixed with the magnesium and starch. This method allows hydraulic fracturing to be conducted in a simpler, more economical, more effective manner as well as in intervals.

  8. Atypical fractures on long term bisphosphonates therapy.

    LENUS (Irish Health Repository)

    Hussein, W


    Bisphosphonates reduce fractures risk in patients with osteoporosis. A new pattern of fractures is now being noted in patients on prolonged bisphosphonate therapy. We report a case of an atypical femoral fracture with preceding pain and highlight the characteristics of these fractures.

  9. Cosmetic rhinoseptoplasty in acute nasal bone fracture. (United States)

    Kim, Ji Heui; Lee, Jung Woo; Park, Chan Hum


    Traditionally, rhinoseptoplasty for nasal bone fracture is only considered after an unsatisfactory outcome from initial closed reduction. However, better surgical outcomes may be achieved if rhinoseptoplasty is performed at the same time as the nasal bone fracture reduction. This study investigated the surgical outcomes of patients who underwent rhinoseptoplasty concomitantly with nasal bone fracture reduction according to their computed tomography image-based nasal bone fracture classifications. Case series with chart review. Academic tertiary care medical center. Fifty-six patients who underwent rhinoseptoplasty concomitantly with nasal bone fracture reduction were enrolled in this study. Nasal bone fractures were classified into 6 types by computed tomography scans. Two independent facial plastic surgeons evaluated the outcomes 6 months postoperatively using a visual analog scale. The nasal tip projection and rotation were measured using the pre- and postoperative profile views. The satisfaction scores of type I, IIo, and IIIo fractures without septal fracture were significantly higher than those of type II, III, and IV fractures with septal fractures. Among the patients, 82.1% underwent lower vault surgery. The nasal tip projection and rotation were increased after surgery in patients without septal fractures, whereas the tip rotation was elevated but the projection was unchanged postoperatively in patients with septal fractures. Rhinoseptoplasty for acute nasal bone fractures can be performed at the same time as nasal bone fracture reduction. However, nasal bone fracture with septal fracture should be managed carefully.

  10. Kertész line of thermally activated breakdown phenomena

    KAUST Repository

    Yoshioka, Naoki


    Based on a fiber bundle model we substantially extend the phase-transition analogy of thermally activated breakdown of homogeneous materials. We show that the competition of breaking due to stress enhancement and due to thermal fluctuations leads to an astonishing complexity of the phase space of the system: varying the load and the temperature a phase boundary emerges, separating a Griffith-type regime of abrupt failure analogous to first-order phase transitions from disorder dominated fracture where a spanning cluster of cracks emerges. We demonstrate that the phase boundary is the Kertész line of the system along which thermally activated fracture appears as a continuous phase transition analogous to percolation. The Kertész line has technological relevance setting the boundary of safe operation for construction components under high thermal loads. © 2010 The American Physical Society.

  11. CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (FALSIRE II)

    Energy Technology Data Exchange (ETDEWEB)

    Bass, B.R.; Pugh, C.E.; Keeney, J. [Oak Ridge National Lab., TN (United States); Schulz, H.; Sievers, J. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koeln (Gemany)


    A summary of Phase II of the Project for FALSIRE is presented. FALSIRE was created by the Fracture Assessment Group (FAG) of the OECD/NEA`s Committee on the Safety of Nuclear Installations (CNSI) Principal Working Group No. 3. FALSIRE I in 1988 assessed fracture methods through interpretive analyses of 6 large-scale fracture experiments in reactor pressure vessel (RPV) steels under pressurized- thermal-shock (PTS) loading. In FALSIRE II, experiments examined cleavage fracture in RPV steels for a wide range of materials, crack geometries, and constraint and loading conditions. The cracks were relatively shallow, in the transition temperature region. Included were cracks showing either unstable extension or two stages of extensions under transient thermal and mechanical loads. Crack initiation was also investigated in connection with clad surfaces and with biaxial load. Within FALSIRE II, comparative assessments were performed for 7 reference fracture experiments based on 45 analyses received from 22 organizations representing 12 countries. Temperature distributions in thermal shock loaded samples were approximated with high accuracy and small scatter bands. Structural response was predicted reasonably well; discrepancies could usually be traced to the assumed material models and approximated material properties. Almost all participants elected to use the finite element method.

  12. Reactive Transport Model of Microbial Reservoir Souring and Remediation in Fractured Rock (United States)

    Cheng, Y.; Bouskill, N.; Wu, Y.; Hubbard, C. G.; Zheng, L.; Arora, B.; Ajo Franklin, J. B.


    Microorganisms mediate the production of hydrogen sulfide (H2S) in oil bearing geological formations. H2S has detrimental impacts on oil production operations and can cause significant environmental and health problems. Oil reservoir souring results from coupled thermal, chemical, biological and hydrological interactions across a range of spatiotemporal scales. At the macroscale, fluid flows in the fractures and matrix determine the delivery of electron donors and acceptors to the microbes, and the flux of H2S throughout the reservoir. At the microscale, microbes reduce sulfate while oxidizing available electron donors for growth. Accumulation of the microbial biomass can in turn impact flows in the fractured geological formation. Understanding the processes that control the rates and patterns of sulfate reduction is a crucial step in developing a predictive understanding of reservoir souring and associated mitigation processes. Recently, a novel fractured sandstone experiment was conducted to explore souring and desouring (perchlorate treatment) across controlled thermal gradient (also in this session). In this work, a reactive transport model (RTM) of the fractured sandstone was developed. Observed spatiotemporal data from the fractured sandstone experiment such as tracer, thermal state, effluent sulfide, sulfate and perchlorate concentrations were used to constrain the model transport and reaction process rates. The model captured the spatiotemporal trends of the chemical species and microbial populations that emerged as a result of feedbacks between microbes, flow and the minerals. This work demonstrates modeling to be a powerful tool for elucidating the interacting factors governing biogenesis of H2S.

  13. [Forensic identification of 50 phalangeal fracture cases]. (United States)

    Ji, Bin; Li, Jia-Qi


    To study the characteristics of forensic identification of phalangeal fracture and to use a combination of medical records, imaging materials, and forensic examination data in identification. Fifty cases of phalangeal fracture involved in the forensic identification were collected from 2009 to 2011. The general situation, the distribution of fracture, the fracture morphology, the injury-causing objects and the results of identification were analyzed retrospectively. Majority of the cases of phalangeal fracture were young and middle-aged men. The index finger and distal phalanx fractures were common. There was no difference in the number of phalangeal fracture between left and right hand. Most of the injury-causing objects were knives and sticks, followed by bricks and stones. The injury-causing objects and modes are related to the morphology of fracture, the distribution of fracture and the severity of the injury. The comprehensive analysis is helpful in forensic identification of phalangeal fracture.

  14. Crushing and Fracture of Lightweight Structures

    DEFF Research Database (Denmark)

    Urban, Jesper


    . Crushing experiments conducted on full-scale aluminum plate intersections reveal that the crushing behaviour is highly affected by material fracture during the deformation. Several fracture criteria from the literature have been reviewed and three fracture models have been compared with material...... on these two fracture models a new fracture criterion, denoted RTCL fracture criterion, is proposed and the fracture criterion is implemented in the FE-program LS-DYNA as a user subroutine. The crushing behaviours of the full-scale aluminum plate intersections have been simulated with LS......-DYNA and the implemented fracture criterion and the simulations agree well with the experiments. New closed form solutions for the dissipated energy during axial compression of aluminum plate intersections have been developed and the effect of fracture is included analytically based of the fracture criterion by Cockcroft...

  15. Vibrations of structurally orthotropic laminated shells under thermal power loading (United States)

    Kogan, E. A.; Lopanitsyn, E. A.


    On the basis of the linearized version of equations obtained in a geometrically nonlinear statement and describing the nonaxisymmetric strain of nonshallow sandwich structure orthotropic shells under thermal power loading, the Rayleigh-Ritz method with polynomial approximation of displacements and shear strains is used to solve the problem of small free vibrations of axisymmetrically thermally preloaded freely supported three-layer conical shell. The causes of dynamical fracture of the shell under study are revealed.

  16. Scale properties of sea ice deformation and fracturing (United States)

    Weiss, Jérôme; Marsan, David


    The sea ice cover, which insulates the ocean from the atmosphere, plays a fundamental role in the Earth's climate system. This cover deforms and fractures under the action of winds, ocean currents and thermal stresses. Along with thermodynamics, this deformation and fracturing largely controls the amount of open water within the ice cover and the distribution of ice thickness, two parameters of high climatic importance, especially during fall and winter (no melting). Here we present a scaling analysis of sea ice deformation and fracturing that allows us to characterize the heterogeneity of fracture patterns and of deformation fields, as well as the intermittency of stress records. We discuss the consequences of these scaling properties, particularly for sea ice modelling in global climate models. We show how multifractal scaling laws can be extrapolated to small scales to learn about the nature of the mechanisms that accommodate the deformation. We stress that these scaling properties preclude the use of homogenisation techniques (i.e. the use of mean values) to link different scales, and we discuss how these detailed observations should be used to constrain sea ice dynamics modelling. To cite this article: J. Weiss, D. Marsan, C. R. Physique 5 (2004).

  17. Rehabilitation of fractures in small animals: maximize outcomes, minimize complications. (United States)

    Doyle, Nancy D


    Successful fracture management accomplishes 2 major objectives: bony union and return to functional activities. For many years, Physical Therapy has routinely helped human patients recovering from fractures reach their functional goals by helping them regain movement, flexibility, strength, coordination, and balance. Rehabilitation is now commonly provided to small animals recovering from fractures to accomplish similar goals. Knowledge of tissue healing is critical when determining the appropriate stresses to apply throughout the healing timeline. The detrimental effects of immobilization, including the potential for development of fracture disease, must be considered when formulating a Rehabilitation plan of care. Many Rehabilitation interventions are readily amenable to application by both Veterinary professionals and owners of patients. Superficial thermal modalities, passive range of motion and stretching, soft tissue massage, therapeutic ultrasound, electrical stimulation, and therapeutic exercise can ensure a more complete patient recovery. Providing owners with education regarding appropriate patient handling and home modifications allows a safer return to the home environment. Detailed written instructions for rehabilitation at home promotes owner compliance and accurate completion.

  18. New C2 synchondrosal fracture classification system

    Energy Technology Data Exchange (ETDEWEB)

    Rusin, Jerome A.; Ruess, Lynne [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States); The Ohio State University College of Medicine and Public Health, Columbus, OH (United States); Daulton, Robert S. [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States)


    Excessive cervical flexion-extension accompanying mild to severe impact injuries can lead to C2 synchondrosal fractures in young children. To characterize and classify C2 synchondrosal fracture patterns. We retrospectively reviewed imaging and medical records of children who were treated for cervical spine fractures at our institution between 1995 and 2014. We reviewed all fractures involving the five central C2 synchondroses with regard to patient demographics, mechanism of injury, fracture pattern, associated fractures and other injuries, treatment plans and outcome. Fourteen children had fractures involving the central C2 synchondroses. There were nine boys and five girls, all younger than 6 years. We found four distinct fracture patterns. Eleven complete fractures were further divided into four subtypes (a, b, c and d) based on degree of anterior displacement of the odontoid segment and presence of distraction. Nine of these 11 children had fractures through both odontoneural synchondroses and the odontocentral synchondrosis; one had fractures involving both neurocentral synchondroses and the odontoneural synchondrosis; one had fractures through bilateral odontoneural and bilateral neurocentral synchondroses. Three children had incomplete fractures, defined as a fracture through a single odontoneural synchondrosis with or without partial extension into either the odontocentral or the adjacent neurocentral synchondroses. All complete fractures were displaced or angulated. Four had associated spinal cord injury, including two contusions (subtype c fractures) and two fatal transections (subtype d fractures). Most children were treated with primary halo stabilization. Subtype c fractures required surgical fixation. We describe four patterns of central C2 synchondrosal fractures, including two unique patterns that have not been reported. We propose a classification system to distinguish these fractures and aid in treatment planning. (orig.)

  19. Preventing Falls and Related Fractures (United States)

    ... ages. Many of us know someone who has fallen and broken a bone. While healing, the fracture ... break after every fall, the person who has fallen and broken a bone nearly always becomes fearful ...

  20. Viscoelastic fracture of biological composites (United States)

    Bouchbinder, Eran; Brener, Efim A.


    Soft constituent materials endow biological composites, such as bone, dentin and nacre, with viscoelastic properties that may play an important role in their remarkable fracture resistance. In this paper we calculate the scaling properties of the quasi-static energy release rate and the viscoelastic contribution to the fracture energy of various biological composites, using both perturbative and non-perturbative approaches. We consider coarse-grained descriptions of three types of anisotropic structures: (i) liquid-crystal-like composites, (ii) stratified composites, (iii) staggered composites, for different crack orientations. In addition, we briefly discuss the implications of anisotropy for fracture criteria. Our analysis highlights the dominant lengthscales and scaling properties of viscoelastic fracture of biological composites. It may be useful for evaluating crack velocity toughening effects and structure-dissipation relations in these materials.

  1. Fracture risk assessed by Fracture Risk Assessment Tool (FRAX) compared with fracture risk derived from population fracture rates

    DEFF Research Database (Denmark)

    Rubin, Katrine Hass; Abrahamsen, Bo; Hermann, Anne Pernille


    Purpose: To evaluate the performance of the Swedish version of Fracture Risk Assessment Tool (FRAX)) without bone mass density (BMD) in a Danish population to examine the possibility of applying this version to Danish women. METHODS: From the Danish National Register of social security numbers, we...... randomly selected 5000 women living in the region of Southern Denmark aged 40-90 years to receive a mailed questionnaire concerning risk factors for osteoporosis based on FRAX. The predicted 10-year probability of hip fractures was calculated for each woman returning a complete questionnaire using...... the Swedish version of FRAX. The observed 10-year hip fracture risk was also calculated for each woman using age-specific hip fracture rates from the National Hospital Discharge Register and National survival tables. RESULTS: A total of 4194 (84%) women responded to the questionnaire and 3636 (73%) gave...

  2. High-performance hierarchical fracturing (United States)

    Cobb, Nicolas B.; Zhang, Weidong


    We describe in more detail a mask data preparation (MDP) flow previously proposed. The focus on this paper is a performance comparison of hierarchical fracturing techniques compared to standard fracturing. Our flow uses GDSII data as input, including a GDSII-based job deck description. The output is maximally compacted, trapezoidal mask writer (MW) formatted data. Our flow takes advantage of hierarchy explicit in the GDSII file(s). This allows optimal determination of 'cover cells', which are repeatable groups of patterns within the data. The use of cover cells allows a reduction of fracturing runtime. In one case, a 21 GB MEBES file was fractured in 30 hours using the standard technique and 53 minutes using the hierarchical cover cell technique.

  3. Computed tomography of calcaneal fractures

    Energy Technology Data Exchange (ETDEWEB)

    Heger, L.; Wulff, K.; Seddiqi, M.S.A.


    Computed tomography (CT) of 25 fractured calcanei was performed to investigate the potential of CT in evaluating the pattern and biomechanics of these fractures. The characteristic findings of typical fractures are presented, including the number and type of principal fragments, size and dislocation of the sustentacular fragment, and involvement of the anterior and posterior facets of the subtalar joint. In 17 cases, the calcaneus consisted of four or more fragments. Furthermore, in 17 cases the sustentacular fragment included all or part of the posterior facet joint. In 18 of the 25 cases, the sustentacular fragment was displaced. It is concluded that well performed CT is an invaluable adjunct in understanding the fracture mechanism and in detecting pain-provoking impingement between the fibular malleolus and the tuberosity fragment.

  4. Sacral stress fractures in athletes. (United States)

    McFarland, E G; Giangarra, C


    Low back and buttock pain in runners can be a source of frustration for the athlete and a diagnostic dilemma for the physician. The authors reported on 3 cases of sacral stress fractures in women athletes, all of which initially presented as low back and/or buttock pain. Sacral stress fractures have been increasingly recognized as a potential cause of these symptoms, especially in young athletes. Because plain radiograph findings are typically normal, the diagnosis is best made with bone scintigraphy. Computed tomography is indicated if there is concern about neoplasm and to evaluate healing of the fracture. If treated with rest, most of these fractures heal and the athlete can return to previous sports activity. The treating physician should be suspicious of this injury among running athletes reporting sacral and buttock pain that does not respond to treatment.

  5. Nonpharmacological prevention of osteoporotic fractures

    Directory of Open Access Journals (Sweden)

    Cathy R Kessenich


    Full Text Available Cathy R KessenichDepartment of Nursing, University of Tampa, Tampa, FL 33606, USA; Nurse Practitioner, Private Practice, Tampa, FLAbstract: Osteoporosis is a systemic, metabolic disease that can result in debilitating fractures. The lasting effects of vertebral and hip fractures can cause acute and chronic pain, deformity, and emotional distress. Research evidence and clinical experience have determined that weight bearing and strength training exercise, fall prevention efforts, hip protectors, and some alternative therapies may assist patients in avoiding the pervasive and lasting effects of osteoporotic fractures. Clinicians should consider the recommendations of nonpharmacological measures to assist patients at risk for experiencing the culminating event of this destructive disease.Keywords: osteoporosis, osteoporotic fracture, osteoporosis prevention

  6. Treatment of Temporal Bone Fractures. (United States)

    Diaz, Rodney C; Cervenka, Brian; Brodie, Hilary A


    Traumatic injury to the temporal bone can lead to significant morbidity or mortality and knowledge of the pertinent anatomy, pathophysiology of injury, and appropriate management strategies is critical for successful recovery and rehabilitation of such injured patients. Most temporal bone fractures are caused by motor vehicle accidents. Temporal bone fractures are best classified as either otic capsule sparing or otic capsule disrupting-type fractures, as such classification correlates well with risk of concomitant functional complications. The most common complications of temporal bone fractures are facial nerve injury, cerebrospinal fluid (CSF) leak, and hearing loss. Assessment of facial nerve function as soon as possible following injury greatly facilitates clinical decision making. Use of prophylactic antibiotics in the setting of CSF leak is controversial; however, following critical analysis and interpretation of the existing classic and contemporary literature, we believe its use is absolutely warranted.

  7. Treatment of Temporal Bone Fractures (United States)

    Diaz, Rodney C.; Cervenka, Brian; Brodie, Hilary A.


    Traumatic injury to the temporal bone can lead to significant morbidity or mortality and knowledge of the pertinent anatomy, pathophysiology of injury, and appropriate management strategies is critical for successful recovery and rehabilitation of such injured patients. Most temporal bone fractures are caused by motor vehicle accidents. Temporal bone fractures are best classified as either otic capsule sparing or otic capsule disrupting-type fractures, as such classification correlates well with risk of concomitant functional complications. The most common complications of temporal bone fractures are facial nerve injury, cerebrospinal fluid (CSF) leak, and hearing loss. Assessment of facial nerve function as soon as possible following injury greatly facilitates clinical decision making. Use of prophylactic antibiotics in the setting of CSF leak is controversial; however, following critical analysis and interpretation of the existing classic and contemporary literature, we believe its use is absolutely warranted. PMID:27648399

  8. Thermal Clothing (United States)


    Gateway Technologies, Inc. is marketing and developing textile insulation technology originally developed by Triangle Research and Development Corporation. The enhanced thermal insulation stems from Small Business Innovation Research contracts from NASA's Johnson Space Center and the U.S. Air Force. The effectiveness of the insulation comes from the microencapsulated phase-change materials originally made to keep astronauts gloved hands warm. The applications for the product range from outer wear, housing insulation, and blankets to protective firefighting gear and scuba diving suits. Gateway has developed and begun marketing thermal regulating products under the trademark, OUTLAST. Products made from OUTLAST are already on the market, including boot and shoe liners, winter headgear, hats and caps for hunting and other outdoor sports, and a variety of men's and women's ski gloves.

  9. Turbulent Thermalization

    CERN Document Server

    Micha, Raphael; Micha, Raphael; Tkachev, Igor I.


    We study, analytically and with lattice simulations, the decay of coherent field oscillations and the subsequent thermalization of the resulting stochastic classical wave-field. The problem of reheating of the Universe after inflation constitutes our prime motivation and application of the results. We identify three different stages of these processes. During the initial stage of ``parametric resonance'', only a small fraction of the initial inflaton energy is transferred to fluctuations in the physically relevant case of sufficiently large couplings. A major fraction is transfered in the prompt regime of driven turbulence. The subsequent long stage of thermalization classifies as free turbulence. During the turbulent stages, the evolution of particle distribution functions is self-similar. We show that wave kinetic theory successfully describes the late stages of our lattice calculation. Our analytical results are general and give estimates of reheating time and temperature in terms of coupling constants and...

  10. The challenge of fracture management in osteoporotic bones ...

    African Journals Online (AJOL)

    capsular) and 10 extra capsular)., 5 fractures of the distal wrist and 8 humeral fractures, 4 rib fractures, 6 pelvic fractures, 2 sternal fractures and 6 tibial fractures. Twenty six (40%) of the above fractures namely the vertebral, ribs, pelvis and sternum ...

  11. Flow upscaling in propped fracture (United States)

    Jasinski, Lukasz; Dabrowski, Marcin


    Proppants in combination with hydraulic fracturing are widely used to maintain the production of oil or gas from low permeability formations (i.e. shale rocks). There are also examples of proppants use in geothermal reservoirs. Flow patterns in propped fracture control transport processes and give information about fracture/matrix exchange surface. Our main motivation is to understand flow behavior in such structures using direct numerical simulations and to find a good upscaling technique to be able to investigate models on reservoir scale. We study fracture made of two parallel plane walls, where void space between them is filled with partial monolayer of proppant. As the fracture is affected by closing pressure, the proppant grains are squeezed between two opposite fracture walls which can change the grain shapes or embed the grains into impermeable rock matrix. To take this effect into account and simplify the geometry, the grains are approximated as cylinders. Imposed macroscopic pressure gradient invokes flow in such medium. As the flow is considered in the low Reynolds number regime, a stationary velocity flow field is obtained by solving the Stokes equations in 3D by means of finite element method. Void space between the grains is accurately discretized by using tetrahedral mesh. To reduce computational effort, the Stokes equation is reduced over the fracture aperture to 2D Stokes-Brinkman equation, which is further numerically solved and compared against numerical solution in 3D. Systematic flow calculations using 2D Stokes-Brinkman equation are performed for periodic domain and no slip boundary condition on the grain surface. Results are discussed in terms of effective properties as a function of geometrical parameters of the medium, such as proppant packing fraction and proppant grain diameter to fracture aperture ratio.

  12. Case Studies in Fracture Mechanics (United States)


    stress. This has been confirmed on low strength aluminium alloy I beams, tested in four point bend- ing, where fracture could not be induced because...applying the fracture data to ET design was to establish a weld acceptance criteria. Here, we decided to consider every weld defect (porosity, dross ...or proof test. CONCLUS IONS In the past the acceptance of internal and external defects in welds, (porosity, dross , cracks, inclusions, and lack-of

  13. [Scaphoid fracture in motocross riders]. (United States)

    Knobloch, K; Krämer, R; Redeker, J; Spies, M; Vogt, P M


    Motocross racing is a demanding motorcycling discipline with significant physiological and psychological demands. Upper extremity injuries are frequently encountered. Interestingly, motocross riders present with a significantly stronger left arm, even if the left hand is not dominant. This difference is attributed to the use of the clutch lever with the left hand, which is more frequent in motocross than in Enduro or desert rally. The wrist has been reported to be involved especially among motocross racers in contrast to road racing. Besides wrist fractures, scaphoid fractures have been previously without a detailed analysis of the injury mechanism. We report on three patients suffering scaphoid fractures caused by extreme hyperextension of the wrist during landing after a motocross jump. Two patients presented late three months following the initial trauma (both Herbert type C fractures), while one motocross athlete with a B 2-type scaphoid fracture was admitted to wrist surgery within a week. The B 2-type fracture was treated with open reduction and Herbert-screw fixation, while the C-type fractures were treated by Herbert-screw fixation in addition to a cortico-cancellous bone graft. Within ten weeks after the surgery the patients were back in sport at their given preoperative level. Hyperextension rather than wrist flexion appears as the predominant mechanism of wrist injuries in motocross riders. A more axial impact on the wrist is more likely to produce a radial fracture during the landing phase. Preventive strategies are internal muscular wrist stabilisation using eccentric training and external stabilisation by rigid gloves allowing only limited hyperextension.

  14. [Talus fractures--fractures of the most important tarsal bone]. (United States)

    Klaue, K


    The talus is the key bone of the foot due to its location between the ankle and the subtalar joints. Through the flexion and extension of the ankle joint, the talus is the "propulsive bone" situated at the root of the first ray and the hallux. Through the subtalar and talo-navicular joints, the talus allows the foot to be "suspended" using a fancy spring mechanism involving ligaments and tendons. The talus thus transmits forces through two important joints without any direct muscular constraint. The talo-calcaneo-navicular joint may be called the "coxa pedis" due to the anatomical and functional similitudes with the coxofemoral joint ("coxa pelvis"). Fractures of the talus are rare. Talus fractures can be classified in "central" and "peripheral" fractures. Central fractures occur through a strong axial blow provided that the ankle and coxa pedis are locked by extrinsic muscular contraction. Peripheral fractures instead occur in an extreme position of the ankle or the coxa pedis, with a subluxation or complete dislocation of one or more of those joints. Central fractures produce a bony solution of continuity in between at least two of the ankle, subtalar and talo-navicular joints. Peripheral fractures mostly do implement joint surfaces which are sheared off. Aim of treating talus fractures is precise and stable reduction of the fragments because most often, the fractures cross the articular layers. The surgical approaches are critical, especially in displaced central fractures, because the reduction may require visual control all around the bone. There are three approaches which might be used as single approaches or combined simultaneously: the anteromedial approach along the subtalar joint from the navicular to the retro-malleolar region, the anterolateral approach centered on the sinus tarsi (Ollier) and the postero-lateral approach (Gallie). In many cases, a joint distraction device may help visualization of the different joint spaces as well as assist reduction

  15. Fractures of the hallux in children. (United States)

    Petnehazy, Thomas; Schalamon, Johannes; Hartwig, Charlotte; Eberl, Robert; Kraus, Tanja; Till, Holger; Singer, Georg


    Foot fractures account for 5% to 13% of pediatric fractures. Fractures of the hallux require special attention due to its role in weight bearing, balance, and pedal motion. In this study, a large series of children with hallux fractures is presented. All children treated with fractures of the hallux between June 2004 and December 2011 were included. The medical records were analyzed and X-rays were reviewed. The fractures were classified according to their anatomic location and the type of fracture. Three hundred seventeen patients (mean age = 11.7 years; range, 1-18 years; 65% male) sustained a fracture of the hallux. Most accidents (28%) occurred at sports facilities, and soccer was the most common cause of a fracture of the hallux (28%). Closed injuries were diagnosed in 92% of the patients; 8% of the children presented with open fractures. In 144 children, the growth plate was affected. Fifty-nine patients presented with diaphyseal fractures, 42 patients with osseous avulsions, and 40 patients with fractures of the distal part of the phalanx. Nineteen children had incomplete and 13 patients comminuted fractures. The vast majority of the children (86%) were treated conservatively. Operative interventions were required in 14% of the patients. Good outcome was achieved in both conservatively and operatively treated patients. In children, fractures of the hallux were most often caused by ball sports and had a good prognosis. The vast majority of these fractures could be treated conservatively yielding good outcome. Level IV, case series. © The Author(s) 2014.

  16. [Ischial tuberosity fractures in children]. (United States)

    Sułko, Jerzy; Olipra, Wojciech; Oberc, Artur


    Ischial tuberosity fractures in children are a form of avulsion fractures caused by the strong thigh muscles of the back group (ischiotibial muscles). Presentation of observations covering the diagnostic difficulties, treatment and follow-up of ischial tuberosity fractures in children. 6 children (one girl and five boys), average age at the time of injury - 13.6 years (12-15.5 years). An analysis of medical and radiological documentation of patients. Two patients with chronic pain were suspected of ischial bone tumor, one was suspected of Perthes disease, and only 3 were sent to the Traumatology Department immediately after the football injury. All patients were treated conservatively. Complete healing of fractures was finally achieved in all patients - (fibrous union in two cases) and finally, after an average period of 9 months, the pain subsided. There is a discussion in medical literature about the difficulties in the diagnosis of ischial tuberosity fractures, which were primarily unrecognized. Radiological picture of significant bone rebuilding may suggest neoplastic lesions. In the literature dominates the attitude of conservative treatment. Only in cases of large displacement of fracture and chronic ailments caused by pressure on the sciatic nerve, surgery should be considered.

  17. Epidemiology of tibial shaft fractures

    Directory of Open Access Journals (Sweden)

    Grecco Marco Aurélio Sertório


    Full Text Available In this work an epidemiological analysis on tibial shaft fractures was performed. During four years, our service treated 179 fractures, 132 in male, 47 in female, aged 14 to 83 years. The 21 to 30-year-old patiens were the more injured. Of these, 120 were open and 59 close fractures of which prevailing cause was road traffic accident. The study based on patients promptuaries analyses and radiographs. The fractures occurred 97 times in the middle third (54.18%; 102 times (56.98% presented simple fragments, and 57 (31.38% oblique lines. We treated close and open fractures, respectively, 48 and 38 cases with plaster cast immobilization; 3 and 67 with external fixation after plaster cast immobilization; 5 and 12 with osteosynthesis by means of plate and screws, and 2 and 3 with external fixation only. In both close and open fractures, respectively, 7 and 20 cases of pseudarthrosis and 1 and 11 of infections have occurred. With the data obtained we verified an actual validity of the epidemiological studies as a contribution for better identifying lesions features and their treatment and complications. This allows proceedings and apprenticeship refinement.

  18. Bilateral Monteggia fracture in adults

    Directory of Open Access Journals (Sweden)

    Ristić Dejan


    Full Text Available Introduction. In 1814 Giovanni Monteggia first described two cases of fractures of the proximal third of ulna with dislocation of the radial head. These fractures are more common in children than in adults, and mutual Monteggia fracture is a rare complication. This study presents a treatment course of a patient with bilateral Monteggia fracture. Case report. A 55- year-old patient was injured by falling in the yard. Radiography showed bilateral Monteggia fracture type II (by the Badon classification. Operative treatment of fracture was done by a compression plate on the right side and by the zuggurtung technique on the left one. Closed repositioning of the radial head was done on both sides. The patient was wearing a plaster splint for the upper arm for 21 days. After removing the fixation, the function of the elbow was determined by the Broberg Morrey score (BM which was on the right side 45.5 and on the left side 47.5. After the proper physical therapy, four months after the surgery, BM score was 100 on the right side, and 93 on the left one. Conclusion. Surgical treatment and early rehabilitation is the key for the return of good function of both elbows.

  19. Open bicondylar Hoffa fracture with patella fracture: a case report and literature review. (United States)

    Mounasamy, Varatharaj; Hickerson, Lindsey; Fehring, Keith; Desai, Pingal


    Bicondylar Hoffa fractures are rare. We report a patient who sustained an open bicondylar Hoffa fracture with an ipsilateral transverse fracture of the patella after a high-energy motor vehicle accident.

  20. Fracture mapping of displaced partial articular fractures of the radial head

    NARCIS (Netherlands)

    Mellema, Jos J.; Eygendaal, Denise; van Dijk, C. Niek; Ring, David; Doornberg, Job N.


    Recognition of patterns of traumatic elbow instability helps anticipate specific fracture characteristics and associated injuries. The objective of this study was to assess the association of fracture line distribution and location of displaced partial articular radial head fractures with specific

  1. Fracture, failure, and fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Dienes, J.K.


    Though continuum descriptions of material behavior are useful for many kinds of problems, particularly those involving plastic flow, a more general approach is required when the failure is likely to involve growth and coalescence of a large number of fractures, as in fragmentation. Failures of this kind appear frequently in rapid dynamic processes such as those resulting from impacts and explosions, particularly in the formation of spall fragments. In the first part of this paper an approach to formulating constitutive relations that accounts for the opening, shear and growth of an ensemble of cracks is discussed. The approach also accounts for plastic flow accompanying fragmentation. The resulting constitutive relations have been incorporated into a Lagrangean computer program. In the second part of this paper a theoretical approach to coalescence is described. The simplest formulation makes use of a linear Liouville equation, with crack growth limited by the mean free path of cracks, assumed constant. This approach allows for an anisotropic distribution of cracks. An alternative approach is also described in which the decrease of the mean free path with increasing crack size is accounted for, but the crack distribution is assumed isotropic. A reduction of the governing Liouville equation to an ordinary differential equation of third order is possible, and the result can be used to determine how mean-free-path decreases with increasing crack size.

  2. Sarcopenia and fragility fractures. (United States)

    Cederholm, T; Cruz-Jentoft, A J; Maggi, S


    Sarcopenia, a reduction in muscle mass and muscle function, is considered one of the hallmarks of the aging process. Current views consider sarcopenia as the consequence of multiple medical, behavioural and environmental factors that characterize aged individuals. Likewise bone fragility is known to depend on several pathogenetic mechanisms leading to bone mass loss and reduction of bone strength. Muscle weakness, fear of falls, falls and subsequent fractures are associated to concurrent sarcopenia and osteoporosis and lead to restricted mobility, loss of autonomy and reduced life expectancy. The skeletal and the muscular organ systems are tightly intertwined: the strongest mechanical forces applied to bones are, indeed, those created by muscle contractions that condition bone density, strength, and microarchitecture. Not surprising, therefore, the decrease in muscle strength leads to lower bone strength. The degenerative processes leading to osteoporosis and sarcopenia show many common pathogenic pathways, like the sensitivity to reduced anabolic hormone secretion, increased inflammatory cytokine activity and reduced physical activity. Thus they may also respond to the same kind of treatments. Basic is life-style interventions related to exercise and nutrition. Sufficient vitamin D levels are of importance for both bone and muscle, primarily provided by sun exposure at younger age, and by supplementation at older age. Resistance training several times per week is crucial, and to be effective adequate access to energy and proteins is necessary.

  3. Numerical simulation of fluid flow and heat transfer in naturally fractured geothermal reservoir using DFN method with matrix flow (United States)

    Lee, Taehun; Lee, Kyungbook; Lee, Hyunsuk; Lee, Wonsuk


    Natural fractures have an effect on the fluid flow and heat transfer in the naturally fractured geothermal reservoir. However, most of the previous works in this area assumed that reservoir systems are continuum model whether it is single continuum or dual continuum. Moreover, some people have studied without continuum model but, it was just pipeline model or didn't calculate heat and fluid flow from matrix. In this paper, we developed a generalized discrete fracture network (DFN) geothermal reservoir simulator consiering fluid flow and heat transfer from matrix. In the model, 2D flow is possible within a rectangular fracture, which is important in thick naturally fractured reservoirs. Also, it can calculate heat conduction between matrix and fracture and matrix can increase temperature of injected water. The DFN model developed in this study was validated for two synthetic fracture systems using a commercial thermal model, TETRAD. Comparison results showed an excellent matching between both models. However, this model is conducted at simple fracture network. Therefore, developed model will be conducted a test in realistic fracture network.

  4. Effect of reclaimed sand additions on mechanical properties and fracture behavior of furan no-bake resin sand

    Directory of Open Access Journals (Sweden)

    Yan-lei Li


    Full Text Available In this work, the effects of reclaimed sand additions on the microstructure characteristics, mechanical properties and fracture behavior of furan no-bake resin sand have been investigated systematically within the temperature range from 25 to 600 篊. The addition of 20%-100% reclaimed sand showed dramatic strength deterioration effect at the same temperature, which is associated with the formation of bonding bridges. Both the ultimate tensile strength (UTS and compressive strength (CS of the moulding sand initially increase with the increase of temperature, and then sharply decrease with the further increase of temperature, which is attributed to the thermal decomposition of furan resin. The addition amount of reclaimed sand has a remarkable effect on the room temperature fracture mode, i.e., with the addition of 0-20% reclaimed sand, the fracture mode was mainly cohesive fracture; the fracture mode converts to be mixture fracture mode as the addition of reclaimed sand increases to 35%-70%; further increasing the addition to 100% results in the fracture mode of typical adhesive fracture. The fracture surface of the bonding bridge changes from a semblance of cotton or holes to smooth with the increase of test temperature.

  5. Making the first fracture the last fracture: ASBMR task force report on secondary fracture prevention

    National Research Council Canada - National Science Library

    Eisman, John A; Bogoch, Earl R; Dell, Rick; Harrington, J Timothy; McKinney, Ross E; McLellan, Alastair; Mitchell, Paul J; Silverman, Stuart; Singleton, Rick; Siris, Ethel


    ...) to reduce future fracture risk and adverse health outcomes. The Task Force reviewed the current evidence about different systematic interventional approaches, their logical background, as well as the medical and ethical rationale...

  6. Evaluations of Strength of Thermal Sprayed Coating for Complex Loading (United States)

    Kaneko, Kenji; Ohmori, Akira

    Fracture strength of WC-12Co thermal sprayed coating is investigated experimentally and analytically. In the experiments, one pair of butt cylindrical specimen with coating is subjected to combined tension with torsion stresses. Fracture loci were obtained for three kinds of thickness of the coating in σ-τ stress plane. Stress distributions at crack tip singular point on fractured surfaces are analyzed by Finite-Element-Method and approximated by the expression σ=KR-λ where R means normalized thickness coordinate. It is found that the normal stress distributions are common to all cases of testing stress conditions and so fracture condition of the brittle coating is represented as K≥Kcr in the normal stress distribution even under mixed deformation mode I and III. The delamination critical shear stress distribution could also be obtained.

  7. Enhanced oil recovery in naturally fractured reservoirs in mexico, technical challenge

    Energy Technology Data Exchange (ETDEWEB)

    Garcia H, Francisco; Meza P, Edgar; Moran O, Oscar [PEMEX - Petroleos Mexicanos, Mexico D.F. (Mexico)


    Unlike single porosity reservoirs, naturally fractured reservoirs have several problems to implant any additional recovery processes (secondary or enhanced) due to a great amount of oil is trapped in the matrix and the injected fluids bypass matrix through fractures because of they have a greater capacity to allow flow. So far there, there is not a complete knowledge of improved recovery processes that can be applied to naturally fractured reservoirs, there are some laboratory tests, tests pilot in fields and very few projects in execution. All this make an opportunity area to develop more investigation. Taking into account the previous limitations is possible to begin to evaluate several processes for naturally fractured reservoirs as: gas injection, chemical treatments and thermal processes, but a common process to all of them is gravity drainage which implies new considerations in operation to extract hydrocarbons of the fractured reservoirs. There are many challenges to implant additional recovery processes in naturally fractured reservoirs and we mentioned in this work, moreover we show Mexican experience in EOR processes in Naturally Fractured Reservoirs, too. (author)

  8. Mechanical strength and analysis of fracture of titanium joining submitted to laser and tig welding

    Directory of Open Access Journals (Sweden)

    Ana Cláudia Gabrielli Piveta


    Full Text Available This study compared the tensile strength and fracture mechanism of tungsten inert gas (TIG welds in cylindrical rods of commercially pure titanium (cp Ti with those of laser welds and intact samples. Thirty dumbbell-shaped samples were developed by using brass rods as patterns. The samples were invested in casings, subjected to thermal cycles, and positioned in a plasma arc welding machine under argon atmosphere and vacuum, and titanium was injected under vacuum/pressure. The samples were X-rayed to detect possible welding flaws and randomly assigned to three groups to test the tensile strength and the fracture mechanism: intact, laser welding, and TIG welding. The tensile test results were investigated using ANOVA, which indicated that the samples were statistically similar. The fracture analysis showed that the cpTi samples subjected to laser welding exhibited brittle fracture and those subjected to TIG welding exhibited mixed brittle/ductile fracture with a predominance of ductile fracture with the presence of microcavities and cleavage areas. Intact samples presented the characteristic straightening in the fracture areas, indicating the ductility of the material.

  9. Microstructural analysis of thermal fatigue damage in 316L pipes


    Gonzalez Sanchez, Sergio; Ruiz, Ana; Nilsson, Karl-Fredrik


    This report summarizes the data and main conclusions derived from microstructural characterisation of 316L pipes subjected to thermal fatigue with a peak temperature of 550°C. TOFD measurements are compared with measured crack depths from cut segments, and fracture mode and corrosion have been assessed by SEM and EDX, respectively.

  10. Thermal Embrittlement of Reactor Pressure Vessel Steel due to Aging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Soo; Park, Duck Gun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    Thermal SS sets are located above the nuclear core where a fast neutron flux is negligible and temperature is 320 .deg. C (as opposed to 290 .deg. C in locations of high-irradiated SS). These SS allow monitoring of continuous operation temperature exposure effect on mechanical characteristics of the steels. Although transgranular cleavage is the predominant mode of brittle fracture in RPV steels, solute (e.g. phosphorus) segregation to grain boundaries can result in another type of brittle fracture known as intergranular (grain boundary) fracture. Figures 1 a) and b) show examples of transgranular and intergranular (IG) fracture, respectively, as viewed in a scanning electron microscope. The investigators have interpreted the intergranular cracking occurs as a result of segregation of sulfur and/or phosphorus at grain boundary. The IG cracking is a kind of symptom of embrittlement. It is reported that the IG cracking occurs in inert (Ar) environment under slow strain rate test. 1. The lath grain size in SA508 RPV steel increases slightly due to thermal aging at 350, 420, and 420 .deg. C for 2,250H. 2. The decrease in toughness appeared 4-25% and the lattice contraction appeared to be +0.004% - -0.022% due to thermal aging at 350, 420, and 420 .deg. C for 2,250H. 3. The amount of decrease in Charpy impact energy due to thermal aging is correlated well with the magnitude of lattice contraction.

  11. Analytical model of transient temperature and thermal stress in ...

    Indian Academy of Sciences (India)

    The result of this work is compared with a ... Keywords. Integral transform method; double end-pumped; laser rod; thermal stress. .... 2.2 Stress analysis. Although different methods have been used to predict failure stress, the maximum tensile hoop stress is proved to model the fracture in laser rod very well [9]. The hotter ...

  12. Oil recovery from naturally fractured reservoirs by steam injection methods. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Reis, J.C.; Miller, M.A.


    Oil recovery by steam injection is a proven, successful technology for nonfractured reservoirs, but has received only limited study for fractured reservoirs. Preliminary studies suggest recovery efficiencies in fractured reservoirs may be increased by as much as 50% with the application of steam relative to that of low temperature processes. The key mechanisms enhancing oil production at high temperature are the differential thermal expansion between oil and the pore volume, and the generation of gases within matrix blocks. Other mechanisms may also contribute to increased production. These mechanisms are relatively independent of oil gravity, making steam injection into naturally fractured reservoirs equally attractive to light and heavy oil deposits. The objectives of this research program are to quantify the amount of oil expelled by these recovery mechanisms and to develop a numerical model for predicting oil recovery in naturally fractured reservoirs during steam injection. The experimental study consists of constructing and operating several apparatuses to isolate each of these mechanisms. The first measures thermal expansion and capillary imbibition rates at relatively low temperature, but for various lithologies and matrix block shapes. The second apparatus measures the same parameters, but at high temperatures and for only one shape. A third experimental apparatus measures the maximum gas saturations that could build up within a matrix block. A fourth apparatus measures thermal conductivity and diffusivity of porous media. The numerical study consists of developing transfer functions for oil expulsion from matrix blocks to fractures at high temperatures and incorporating them, along with the energy equation, into a dual porosity thermal reservoir simulator. This simulator can be utilized to make predictions for steam injection processes in naturally-fractured reservoirs. Analytical models for capillary imbibition have also been developed.

  13. Tensile and fracture toughness test results of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Moons, F.; Puzzolante, J.L. [Centre d`Etude de l`Energie Nucleaire, Mol (Belgium)


    Tensile and fracture toughness test results of four Beryllium grades are reported here. The flow and fracture properties are investigated by using small size tensile and round compact tension specimens. Irradiation was performed at the BR2 material testing reactor which allows various temperature and irradiation conditions. The fast neutron fluence (>1 MeV) ranges between 0.65 and 2.45 10{sup 21} n/cm{sup 2}. In the meantime, un-irradiated specimens were aged at the irradiation temperatures to separate if any the effect of temperature from irradiation damage. Test results are analyzed and discussed, in particular in terms of the effects of material grade, test temperature, thermal ageing and neutron irradiation. (author)

  14. Casting: Pearls and pitfalls learned while caring for children's fractures. (United States)

    Nguyen, Shawn; McDowell, Mitchell; Schlechter, John


    Casting is a routine procedure used for fracture care in the pediatric population. The purpose of this review is to provide pearls and pitfalls that our institution has learned from previous literature. When applying the cast, we recommend using cotton padding for the liner and fiberglass or plaster depending on how much swelling is expected. A well-molded cast must be applied in order to prevent further fracture displacement. Cast valving is a valuable technique that allows a decrease in pressure which prevents discomfort and complications like compartment syndrome. Preventing thermal injuries, skin complications, and a wet cast are other important considerations when caring for casts. Appropriate use of a cast saw, avoiding pressure spots, and properly covering the cast are ways to respectively prevent those complications. Lastly, patient education remains one of the most valuable tools in ensuring proper cast maintenance.

  15. Fracture mechanics analyses of ceramic/veneer interface under mixed-mode loading. (United States)

    Wang, Gaoqi; Zhang, Song; Bian, Cuirong; Kong, Hui


    Few studies have focused on the interface fracture performance of zirconia/veneer bilayered structure, which plays an important role in dental all-ceramic restorations. The purpose of this study was to evaluate the fracture mechanics performance of zirconia/veneer interface in a wide range of mode-mixities (at phase angles ranging from 0° to 90°), and to examine the effect of mechanical properties of the materials and the interface on the fracture initiation and crack path of an interfacial crack. A modified sandwich test configuration with an oblique interfacial crack was proposed and calibrated to choose the appropriate geometry dimensions by means of finite element analysis. The specimens with different interface inclination angles were tested to failure under three-point bending configuration. Interface fracture parameters were obtained with finite element analyses. Based on the interfacial fracture mechanics, three fracture criteria for crack kinking were used to predict crack initiation and propagation. In addition, the effects of residual stresses due to coefficient of thermal expansion mismatch between zirconia and veneer on the crack behavior were evaluated. The crack initiation and propagation were well predicted by the three fracture criteria. For specimens at phase angle of 0, the cracks propagated in the interface; whereas for all the other specimens the cracks kinked into the veneer. Compressive residual stresses in the veneer can improve the toughness of the interface structure. The results suggest that, in zirconia/veneer bilayered structure the veneer is weaker than the interface, which can be used to explain the clinical phenomenon that veneer chipping rate is larger than interface delamination rate. Consequently, a veneer material with larger fracture toughness is needed to decrease the failure rate of all-ceramic restorations. And the coefficient of thermal expansion mismatch of the substrates can be larger to produce larger compressive

  16. Radiographic anatomy of the proximal femur: femoral neck fracture vs. transtrochanteric fracture

    Directory of Open Access Journals (Sweden)

    Ana Lecia Carneiro Leão de Araújo Lima

    Full Text Available ABSTRACT OBJECTIVE: To evaluate the correlation between radiographic parameters of the proximal femur with femoral neck fractures or transtrochanteric fractures. METHODS: Cervicodiaphyseal angle (CDA, femoral neck width (FNW, hip axis length (HAL, and acetabular tear drop distance (ATD were analyzed in 30 pelvis anteroposterior view X-rays of patients with femoral neck fractures (n = 15 and transtrochanteric fractures (n = 15. The analysis was performed by comparing the results of the X-rays with femoral neck fractures and with transtrochanteric fractures. RESULTS: No statistically significant differences between samples were observed. CONCLUSION: There was no correlation between radiographic parameters evaluated and specific occurrence of femoral neck fractures or transtrochanteric fractures.

  17. Fracture opening/propagation behavior and their significance on pressure-time records during hydraulic fracturing

    Energy Technology Data Exchange (ETDEWEB)

    Takashi Kojima; Yasuhiko Nakagawa; Koji Matsuki; Toshiyuki Hashida


    Hydraulic fracturing with constant fluid injection rate was numerically modeled for a pair of rectangular longitudinal fractures intersecting a wellbore in an impermeable rock mass, and numerical calculations have been performed to investigate the relations among the form of pressure-time curves, fracture opening/propagation behavior and permeability of the mechanically closed fractures. The results have shown that both permeability of the fractures and fluid injection rate significantly influence the form of the pressure-time relations on the early stage of fracture opening. Furthermore it has been shown that wellbore pressure during fracture propagation is affected by the pre-existing fracture length.

  18. Fracture union in closed interlocking nail in humeral shaft fractures. (United States)

    Sahu, Ramji Lal; Ranjan, Rajni; Lal, Ajay


    Fracture shaft humerus is a major cause of morbidity in patients with upper extremity injuries. The aim of this study was to evaluate the outcome of interlocking nail in humeral shaft fractures. This study was conducted in the Department of Orthopedic Surgery in SMS and R Sharda University from January 2010 to November 2013. Seventy-eight patients were recruited from emergency and out-patient department having a close fracture of humerus shaft. All patients were operated under general anesthesia and closed reamed interlocking nailing was done. All patients were followed for 9 months. Out of 78 patients, 69 patients underwent union in 90-150 days with a mean of 110.68 days. Complications found in four patients who had nonunion, and five patients had delayed union, which was treated with bone grafting. All the patients were assessed clinically and radiologically for fracture healing, joint movements and implant failure. The results were excellent in 88.46% and good in 6.41% patients. Complete subjective, functional, and clinical recovery had occurred in almost 100% of the patients. The results of the present study indicates that in the presence of proper indications, reamed antegrade intramedullary interlocked nailing appears to be a method of choice for internal fixation of osteoporotic and pathologic fractures.

  19. Which Fractures Are Most Attributable to Osteoporosis? (United States)

    Warriner, Amy H.; Patkar, Nivedita M.; Curtis, Jeffrey R.; Delzell, Elizabeth; Gary, Lisa; Kilgore, Meredith; Saag, Kenneth G.


    Background Determining anatomic sites and circumstances under which a fracture may be a consequence of osteoporosis is a topic of ongoing debate and controversy that is important to both clinicians and researchers. Methods We conducted a systematic literature review and generated an evidence report on fracture risk based on specific anatomic bone sites as well as fracture diagnosis codes. Using the RAND/UCLA appropriateness process, we convened a multi-disciplinary panel of 11 experts who rated fractures according to their likelihood of being due to osteoporosis based on the evidence report. Fracture sites (as determined by ICD-CM codes) were stratified by four clinical risk factor categories based on age, sex, race/ethnicity (African- American and Caucasian) and presence or absence of trauma. Results Consistent with current clinical experience, the fractures rated most likely due to osteoporosis were the femoral neck, pathologic fractures of the vertebrae, and lumbar and thoracic vertebral fractures. The fractures rated least likely due to osteoporosis were open proximal humerus fractures, skull, and facial bones. The expert panel rated open fractures of the arm (except proximal humerus) and fractures of the tibia/fibula, patella, ribs, and sacrum as being highly likely due to osteoporosis in older Caucasian women but a lower likelihood in younger African American men. Conclusion Osteoporosis attribution scores for all fracture sites were determined by a multidisciplinary expert panel to provide an evidence-based continuum of the likelihood of a fracture being associated with osteoporosis. PMID:21130353

  20. Time-dependent analytical thermal model to investigate thermally induced stresses in quasi-CW-pumped laser rods

    CSIR Research Space (South Africa)

    Bernhardi, EH


    Full Text Available One of the main problems that limit the power scaling of diode-end-pumped solid-state lasers is the generation of heat inside the laser gain medium which can ultimately cause fracture. In this paper a time-dependent analytical thermal model...

  1. Thermal insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.


    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  2. Talar neck and body fractures. (United States)

    Rammelt, Stefan; Zwipp, Hans


    Fractures of the talar neck and body are rare and serious injuries. The vast majority are either intra-articular or lead indirectly to an intra-articular incongruity through a dislocation at the talar neck. Because of the high energy needed to produce talar fractures, they are frequently seen in multiply injured and polytraumatised patients. Open fractures and fracture-dislocations are treated as emergencies. Preoperative planning of definite internal fixation requires CT scanning. To obtain a complete intra-operative overview allowing for anatomical reconstruction of the articular surfaces and the axial deviation bilateral approaches are usually necessary. Internal fixation is achieved with screws or mini-plates supplemented by temporary K-wire transfixation in cases of marked additional ligamentous instability. The clinical outcome after talar neck and body fractures is determined by the severity of the injury and the quality of reduction and internal fixation. The timing of definite internal fixation does not appear to affect the final result. The rates of avascular necrosis (AVN) correlate with the degree of initial dislocation. Only total AVN with collapse of the talar body leads to inferior results with the need for further surgery whilst prolonged immobilisation or offloading of the affected foot is not indicated for partial AVN. Talar malunions and non-unions after inadequate treatment of displaced fractures are debiliating conditions that should be treated by surgical correction. Treatment options include corrective osteotomy by recreating the former fracture with secondary fixation, free or vascularised bone grafting and salvage by realignment and fusion of the affected joint(s).

  3. Factors affecting the thermal shock resistance of several hafnia based composites containing graphite or tungsten. M.S. Thesis (United States)

    Lineback, L. D.


    The thermal shock resistance of hafnia based composites containing graphite powder or tungsten fibers was investigated in terms of material properties which include thermal expansion, thermal conductivity, compressive fracture stress, modulus of elasticity, and phase stability in terms of the processing parameters of hot pressing pressure and/or density, degree of stabilization of the hafnia, and composition. All other parameters were held constant or assumed constant. The thermal shock resistance was directly proportional to the compressive fracture stress to modulus of elasticity ratio and was not affected appreciably by the small thermal expansion or thermal conductivity changes. This ratio was found to vary strongly with the composition and density such that the composites containing graphite had relatively poor thermal shock resistance, while the composites containing tungsten had superior thermal shock resistance.

  4. Foot and Ankle Stress Fractures in Athletes. (United States)

    Greaser, Michael C


    The incidence of stress fractures in the general athletic population is less than 1%, but may be as high as 15% in runners. Stress fractures of the foot and ankle account for almost half of bone stress injuries in athletes. These injuries occur because of repetitive submaximal stresses on the bone resulting in microfractures, which may coalesce to form complete fractures. Advanced imaging such as MRI and triple-phase bone scans is used to evaluate patients with suspected stress fracture. Low-risk stress fractures are typically treated with rest and protected weight bearing. High-stress fractures more often require surgical treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Rare stress fracture: longitudinal fracture of the femur. (United States)

    Pérez González, M; Velázquez Fragua, P; López Miralles, E; Abad Moretón, M M


    42-year-old man with pain in the posterolateral region of the right knee that began while he was running. Initially, it was diagnosed by magnetic resonance (MR) as a possible aggressive process (osteosarcoma or Ewing's sarcoma) but with computed tomography it was noted a cortical hypodense linear longitudinal image with a continuous, homogeneous and solid periosteal reaction without clear soft tissue mass that in this patient suggest a longitudinal distal femoral fatigue stress fracture. This type of fracture at this location is very rare. Stress fractures are entities that can be confused with an agressive process. MR iscurrently the most sensitive and specific imaging method for its diagnosis. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Fracture and Medium Modeling, by Analizing Hidraulic Fracturing Induced Microseismicity (United States)

    Gomez Alba, S.; Vargas Jiménez, C. A.


    Hydraulic fracturing is an essential technology for most unconventional hydrocarbon resources and many conventional ones as well. The primary limitation on the improvement and optimization of the fracturing process is the minimal access to observe the behavior of the fracture in the subsurface. Without direct observational evidence, hypothetical mechanisms must be assumed and then tested for their validity with indirect information such as wellbore measurements, indirect production and pressure behavior. One of the most important sources of information today is the relation made between micro seismic source mechanisms and fracture behavior. Hydraulic fractures induce some level of micro seismicity when the stress conditions in the Earth are altered by changes in stress during the operations. The result is the sudden movement between rock elements and the radiation of both compressional and shear energy in a seismic range that can be detected and recorded with sensitive receivers. The objective of this work is to provide reasonable information when applying inversion methods in order to estimate the vertical and horizontal spatial heterogeneities in medium and energy radiation distribution of microseisms while fracking operations. The method consist in record microseisms at a previous lineal array of stations (triaxial accelerometers) which are located close to the source coordinates and cover the area of study. The analysis clarify some ideas about what information can be gained from the micro seismic source data and according to the obtained results, what kind of comparisons and associations might be done to evaluate the fracking performance operation. Non uniformities in medium such as faults would be revealed by interpreted scattering coefficients. Fracture properties like distance, velocity and orientation would be also determined by analyzing energy radiation.

  7. Mandibular fracture in a neonate. (United States)

    Gopalakrishnan, V; Sahoo, N K; Roy, I D


    Mandibular fractures in the neonate are rare. The aetiological factors are traumatic delivery, accidental fall, road traffic accidents, and attempted infanticide. The diagnosis is difficult due to facial oedema masking the clinical features and the absence of dentition. The treatment of fractures in the newborn represents a unique problem in terms of investigations, diagnosis, selection of anaesthesia, and method of fixation. The case of a 1-day-old infant referred for the management of a mandibular fracture sustained in an accidental fall is presented herein. During oral suctioning, the neonatologist observed continuous blood-stained secretions, which raised the suspicion of a trauma to the oral cavity. The infant was diagnosed as having a fracture of the mandibular symphysis with displacement. The fracture was reduced under local anaesthesia with sedation, and was stabilized with an acrylic splint, which was secured with circum-mandibular wiring. The patient was followed up for 1.5 years and the healing was satisfactory. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  8. Selective perceptions of hydraulic fracturing. (United States)

    Sarge, Melanie A; VanDyke, Matthew S; King, Andy J; White, Shawna R


    Hydraulic fracturing (HF) is a focal topic in discussions about domestic energy production, yet the American public is largely unfamiliar and undecided about the practice. This study sheds light on how individuals may come to understand hydraulic fracturing as this unconventional production technology becomes more prominent in the United States. For the study, a thorough search of HF photographs was performed, and a systematic evaluation of 40 images using an online experimental design involving N = 250 participants was conducted. Key indicators of hydraulic fracturing support and beliefs were identified. Participants showed diversity in their support for the practice, with 47 percent expressing low support, 22 percent high support, and 31 percent undecided. Support for HF was positively associated with beliefs that hydraulic fracturing is primarily an economic issue and negatively associated with beliefs that it is an environmental issue. Level of support was also investigated as a perceptual filter that facilitates biased issue perceptions and affective evaluations of economic benefit and environmental cost frames presented in visual content of hydraulic fracturing. Results suggested an interactive relationship between visual framing and level of support, pointing to a substantial barrier to common understanding about the issue that strategic communicators should consider.

  9. Fractures of the femoral neck. (United States)

    Lein, T; Bula, P; Jeffries, J; Engler, K; Bonnaire, F


    The ideal treatment of the intracapsular fracture of the femoral neck still is subject of discussion. The demographic development of the population in Europe with fractures of the neck of femur being typical in the older patient, requires conclusive and stringent concepts of treatment. Adequate and patient oriented therapy should be promoted, regional differences and provisional deficiencies need to be adjusted in order to minimize the rate of complications. The guideline "Schenkelhalsfraktur" of the German board of trauma surgeons, the 'Deutsche Gesellschaft für Unfallchirurgie', and the article at hand are meant to serve as a manual for the trauma surgeon. Based on evaluated data it simplifies rational decision-making for treatment of fractures of the proximal femur. Moreover, secondary prophylaxis as well as the subsequent outpatient treatment and the social reintegration of the patients recovering from fractures of the femoral neck remains vital- ly important. After all, even with ideal treatment of the fracture more than half of the patients are impaired for a long time and one out of four permanently depends on nursing assistance.

  10. Acetabular Fractures in the Elderly

    Directory of Open Access Journals (Sweden)

    Joshua L. Gary


    Full Text Available As the population ages, the incidence of osteoporotic fractures, including those of the pelvis and acetabulum, continues to rise. Treatment of the elder patients with an acetabular fracture is much more controversial than the treatment of younger patients with similar injuries, where prevention of posttraumatic arthritis and total hip replacement remains optimal to limit need for revision arthroplasty. Arthroplasty for fractures of the proximal femur is commonplace in an older population and is a mainstay of treatment to promote early mobilization and weight-bearing. However, even with acute total hip arthroplasty for a geriatric acetabular fracture, most surgeons do not permit immediate weight-bearing postoperatively. Therefore, controversy regarding optimal treatment of these challenging fractures persists. Four treatment options have emerged: nonoperative treatment with early mobilization, open reduction and internal fixation (ORIF, limited open reduction and percutaneous screw fixation, and acute total hip arthroplasty. The exact indications and benefits of each treatment remain unknown. This article serves as a review of these four treatments and the data existing to support them.

  11. High prevalence of simultaneous rib and vertebral fractures in patients with hip fracture. (United States)

    Lee, Bong-Gun; Sung, Yoon-Kyoung; Kim, Dam; Choi, Yun Young; Kim, Hunchul; Kim, Yeesuk


    The purpose was to evaluate the prevalence and location of simultaneous fracture using bone scans in patients with hip fracture and to determine the risk factors associated with simultaneous fracture. One hundred eighty two patients with hip fracture were reviewed for this study. Clinical parameters and bone mineral density (BMD) of the lumbar vertebra and femoral neck were investigated. To identify acute simultaneous fracture, a bone scan was performed at 15.4±4.1days after hip fracture. The prevalence and location of simultaneous fracture were evaluated, and multivariate logistic regression analysis was performed to determine the risk factors. Simultaneous fracture was observed in 102 of 182 patients, a prevalence of 56.0%. Rib fracture was the most common type of simultaneous fracture followed by rib with vertebral fracture. The BMD of the lumbar vertebra was significantly lower in patients with simultaneous fracture (p=0.044) and was identified as an independent risk factor (odds ratio: OR 0.05, 95% confidence interval: CI 0.01-0.57). The prevalence of simultaneous fracture was relatively high among patients with hip fracture, and BMD was significantly lower in patients with simultaneous fracture than in patients without it. Surgeons should be aware of the possibility of simultaneous fracture in patients with hip fracture. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Hot and steamy fractures in the Philippines: the characterisation and permeability evaluation of fractures of the Southern Negros Geothermal Field, Negros Oriental, Philippines (United States)

    Pastoriza, Loraine; Holdsworth, Robert; McCaffrey, Kenneth; Dempsey, Eddie; Walker, Richard; Gluyas, Jon; Reyes, Jonathan


    Fluid flow pathway characterisation is critical to geothermal exploration and exploitation. It requires a good understanding of the structural evolution, fault distribution and fluid flow properties. A dominantly fieldwork-based approach has been used to evaluate the potential fracture permeability characteristics of a typical high-temperature geothermal reservoir in the Southern Negros Geothermal Field, Philippines. This is a liquid-dominated geothermal resource hosted in the andesitic to dacitic Quaternary Cuernos de Negros Volcano in Negros Island. Fieldwork reveals two main fracture groups based on fault rock characteristics, alteration type, relative age of deformation, and associated thermal manifestation, with the younger fractures mainly related to the development of the modern geothermal system. Palaeostress analyses of cross-cutting fault and fracture arrays reveal a progressive counterclockwise rotation of stress axes from the (?)Pliocene up to the present-day, which is consistent with the regional tectonic models. A combined slip and dilation tendency analysis of the mapped faults indicates that NW-SE structures should be particularly promising drilling targets. Frequency versus length and aperture plots of fractures across six to eight orders of magnitude show power-law relationships with a change in scaling exponent in the region of 100 to 500m length-scales. Finally, evaluation of the topology of the fracture branches shows the dominance of Y-nodes that are mostly doubly connected suggesting good connectivity and permeability within the fracture networks. The results obtained in this study illustrate the value of methods that can be globally applied during exploration to better characterize fracture systems in geothermal reservoirs using multiscale datasets.

  13. The radiation swelling effect on fracture properties and fracture mechanisms of irradiated austenitic steels. Part I. Ductility and fracture toughness

    Energy Technology Data Exchange (ETDEWEB)

    Margolin, B., E-mail:; Sorokin, A.; Shvetsova, V.; Minkin, A.; Potapova, V.; Smirnov, V.


    The radiation swelling effect on the fracture properties of irradiated austenitic steels under static loading has been studied and analyzed from the mechanical and physical viewpoints. Experimental data on the stress-strain curves, fracture strain, fracture toughness and fracture mechanisms have been represented for austenitic steel of 18Cr-10Ni-Ti grade (Russian analog of AISI 321 steel) irradiated up to neutron dose of 150 dpa with various swelling. Some phenomena in mechanical behaviour of irradiated austenitic steels have been revealed and explained as follows: a sharp decrease of fracture toughness with swelling growth; untypical large increase of fracture toughness with decrease of the test temperature; some increase of fracture toughness after preliminary cyclic loading. Role of channel deformation and channel fracture has been clarified in the properties of irradiated austenitic steel and different tendencies to channel deformation have been shown and explained for the same austenitic steel irradiated at different temperatures and neutron doses.

  14. Unstable Pelvic Fractures Associated with Femoral Shaft Fractures: A Retrospective Analysis

    Directory of Open Access Journals (Sweden)

    Chun-Liang Wu


    Full Text Available Background: Both pelvic fractures and femoral shaft fractures are caused by high-energy injuries. When unstable pelvic fractures and femoral shaft fractures occur concomitantly, the optimal treatment method is controversial. The aim of this study was to establish a reasonable principle for treating such complicated injuries. Methods: Forty patients sustaining unstable pelvic fractures and concomitant femoral shaft fractures were treated in a 7-year period. The initial management of the fractures was started at the emergency service according to the Advanced Trauma Life Support protocol. Unstable pelvic fractures were wrapped by cloth sheets and femoral shaft fractures were immobilized with a splint. Angiography was performed on patients with unstable hemodynamic status. The definitive treatment for combined fractures was performed after stabilizing the hemodynamics. Closed nailing was used for femoral shaft fractures, and pelvic fractures were treated with various techniques. Results: The mortality rate was 12.5% (5/40 during admission. Thirty-three patients were followed up for an average of 32 months (range, 12-76 months. There were 33 cases of unstable pelvic fractures and 36 instances of femoral shaft fractures. The union rate for pelvic fractures was 100% (33/33, while femoral shaft fractures had a 94.4% (34/36 union rate. The average healing time was 3.3 months (range, 1.6-8.1 months and 4.1 months (range, 2.5-18.2 months for pelvic and femoral shaft fractures, respectively. After fracture, 34 hips (94% achieved a satisfactory result in the Harris hip score and 30 knees (83% achieved a satisfactory result in the Mize knee score. Conclusions: Stabilization of the hemodynamics in patients with combined fractures should be the first aim. Angiography to stop arterial bleeding in the pelvis is often life-saving. The definitive treatment for combined fractures, such as pelvic fractures and femoral shaft fractures, should wait until hemodynamics

  15. Olfactory Dysfunction in Nasal Bone Fracture. (United States)

    Kim, Sug Won; Park, Beom; Lee, Tae Geun; Kim, Ji Ye


    All nasal bone fractures have the potential for worsening of olfactory function. However, few studies have studied the olfactory outcomes following reduction of nasal bone fractures. This study evaluates posttraumatic olfactory dysfunction in patients with nasal bone fracture before and after closed reduction. A prospective study was conducted for all patients presenting with nasal bone fracture (n=97). Each patient consenting to the study underwent the Korean version of Sniffin' Sticks test (KVSS II) before operation and at 6 month after closed reduction. The nasal fractures were divided according to the nasal bone fracture classification by Haug and Prather (Types I-IV). The olfactory scores were compared across fracture types and between preoperative and postoperative settings. Olfactory dysfunction was frequent after nasal fracture (45/97, 46.4%). Our olfactory assessment using the KVSS II test revealed that fracture reduction was not associated with improvements in the mean test score in Type I or Type II fractures. More specifically, the mean posttraumatic Threshold, discrimination and identification score decreased from 28.8 points prior to operation to 23.1 point at 6 months for Type II fracture with septal fracture. Our study has revealed two alarming trends regarding post-nasal fracture olfactory dysfunction. First, our study demonstrated that almost half (46.4%) of nasal fracture patients experience posttraumatic olfactory dysfunction. Second, closed reduction of these fractures does not lead to improvements olfaction at 6 months, which suggest that olfactory dysfunction is probably due to factors other than the fracture itself. The association should be further explored between injuries that lead to nasal fracture and the mechanism behind posttraumatic olfactory dysfunction.


    Tang, Yang; Hu Xiaopeng; Lu, Xiongwei; Zhang, Yuntong; Zhang, Chuncai; Wang, Panfeng; Zhao, Xue


    To study the experimental biomechanics of acetabular posterior wall fractures so as to provide theoretical basis for its clinical treatment. Six formalin-preserved cadaveric pelvises were divided into groups A and B (n=3). The fracture models of superior-posterior wall and inferior-posterior wall of the acetabulum were created on both hips in group A; fractures were fixed with two interfragmentary screws and a locking reconstruction plate. The fracture models of superior-posterior wall of acetabulum were created on both hips in group B; fractures were fixed with two interfragmentary screws and a locking reconstruction plate at one side, and with acetabular tridimensional memory fixation system (ATMFS) at the other side. The biomechanical testing machine was used to load to 1 500 N at 10 mm/min speed for 30 seconds. The displacement of superior and inferior fracture sites was analyzed with the digital image correlation technology. No fracture or internal fixation breakage occurred during loading and measuring; the displacement valuess of the upper and lower fracture lines were below 2 mm (the clinically tolerable maximum value) in 2 groups. In group A, the displacement values of the upper and lower fracture lines at superior-posterior wall fracture site were significantly higher than those at inferior-posterior wall fracture site (P fracture line were significantly higher than those of lower fracture line (P fracture types. In group B, the displacement values of the upper and lower fracture lines at the side fixed with screws and a locking reconstruction plate were similar to the values at the side fixed with ATMFS, all being close to 2 mm; the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P acetabulum is much greater than that of the inferior-posterior wall of acetabulum and they should be discriminated, which might be the reasons of reduction loss, femoral head subluxation, and traumatic arthritis

  17. Plain film analysis of acetabular fracture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Soo; Han, Sang Suk; Yoon, Eu Giene; Cha, Seong Sook; Eun, Tchoong Kie; Chung, Duck Hwan [Inje Medical College Paik Hospital, Pusan (Korea, Republic of)


    Acetabular fracture can result in severe limitation of the motion of the hip joint, which supports total weight of human body. Because of different methods of surgical approach according to fracture type, precise interpretation of X-ray films of acetabular fracture is required. We reviewed 38 cases of simple X-ray films showing acetabular fracture. The results were as follows: 1. Almost 60% of the cases-were in their 2nd and 3rd decades. 2. Twenty cases were male, and 18 cases were female. 3. The most common cause of the injury was traffic accident (33 cases, 86.8%), followed by fall down (4 cases, 10.5%), and slip down (1 case, 2.7%). 4. Elementary fractures were 21 cases (55.3%), and associated fractures were 17 cases (44.7%). 5. Among elementary fractures, posterior wall fractures were 9 cases (23.7%), followed by anterior column fractures (8 cases, 21.1%), anterior wall fractures (4 cases, 10.5%). 6. Among associated fractures, T-shaped fractures were 8 cases (21.1%), followed by both column fractures (6 cases, 15.8%), anterior and hemitransverse fractures (3 cases, 7.8%). 7. Other pelvic bone fractures associated with the acetabular fracture were as follows: fractures of contralateral pubic rami (6 cases, 15.8%) contralateral iliac bone (1 case, 2.6%) and ipsilateral iliac bone (1 case, 2.6%). 8. Injuries of other organs adjacent to the acetabulum were as follows: rupture of the bladder (3 cases, 7.9%), urethra (2 cases, 5.3%) and uterus (1 cases, 2.6%)

  18. Fractures of the calcaneus in racing greyhounds. (United States)

    Ost, P C; Dee, J F; Dee, L G; Hohn, R B


    Fifty-one calcaneus fractures associated with (41) or without (10) central tarsal bone (Tc) fractures in racing greyhounds were evaluated and categorized. All calcaneal fractures with no Tc fractures had a plantar proximal intertarsal subluxation. No subluxations were found in dogs with both calcaneal and central tarsal fractures. The calcaneal fractures were treated either with coaptation splints or surgical repair. Surgical techniques included a Steinmann pin with a figure eight tension band device or screw or plate fixation as primary techniques supplemented by Kirschner wires and cerclage wires. In all calcaneal fractures associated with plantar proximal intertarsal subluxation, an arthrodesis of the calcaneoquartal joint was performed. All 22 surgically repaired fractures in dogs available for physical and radiographic reexamination had healed within 1 to 6 months. Eight dogs with fractures of the calcaneus associated with fractures of Tc returned to a racing career. None of the dogs with plantar proximal intertarsal subluxation raced again. Based on the orientation of the fracture lines and on dissection of two tarsi with calcaneal fractures, a hypothesis on the pathogenesis of calcaneal fractures in racing greyhounds was formulated.


    Energy Technology Data Exchange (ETDEWEB)

    Anthony R. Kovscek


    This technical progress report describes work performed from April 1 through June 30, 2002, for the project ''Heavy and Thermal Oil Recovery Production Mechanisms.'' We investigate a broad spectrum of topics related to thermal and heavy-oil recovery. Significant results were obtained in the areas of multiphase flow and rock properties, hot-fluid injection, improved primary heavy oil recovery, and reservoir definition. The research tools and techniques used are varied and span from pore-level imaging of multiphase fluid flow to definition of reservoir-scale features through streamline-based history-matching techniques. Briefly, experiments were conducted to image at the pore level matrix-to-fracture production of oil from a fractured porous medium. This project is ongoing. A simulation studied was completed in the area of recovery processes during steam injection into fractured porous media. We continued to study experimentally heavy-oil production mechanisms from relatively low permeability rocks under conditions of high pressure and high temperature. High temperature significantly increased oil recovery rate and decreased residual oil saturation. Also in the area of imaging production processes in laboratory-scale cores, we use CT to study the process of gas-phase formation during solution gas drive in viscous oils. Results from recent experiments are reported here. Finally, a project was completed that uses the producing water-oil ratio to define reservoir heterogeneity and integrate production history into a reservoir model using streamline properties.

  20. Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

    Directory of Open Access Journals (Sweden)

    Ungyu Paik


    Full Text Available The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF and low-pressure plasma spray (LPPS methods showed a partial cracking (and/or delamination and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50% after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF.


    Directory of Open Access Journals (Sweden)

    Stjepan Antolović


    Full Text Available The interest and performance of horizontal drilling and completions has increased during the last two decades. Horizontal wells are advantageous compared to vertical wells in thin reservoirs, reservoirs with favorable vertical permeability and reservoirs with water and gas coning problems. In many reservoirs, the ratio of horizontal permeability to the vertical permeability is substantially larger than one and often is close to 10. Thus, these reservoirs are very good candidates for hydraulic fracturing. By hydraulic fracturing one or more fractures are created, which can be longitudinal or orthogonal. By that, flow is altered and it mostly conducts horizontally through reservoir toward horizontal wellbore. With this altered flow, fluid is produced faster, with less pressure loss by fluid unit of produced fluid. Some of the existing mathematical models to determine the productivity of multifractured horizontal wells are presented in this work (the paper is published in Croatian.

  2. Fractured Penis: Not So Rare! (United States)

    Tamhankar, Ashwin S; Pawar, Prakash W; Sawant, Ajit S; Kasat, Gaurav V; Savaliya, Abhishek; Mundhe, Shankar; Patil, Sunil; Narwade, Sayalee


    Penile fracture is a relatively common phenomenon. The main problem associated with this condition is the lack of patients' awareness on the urgency of the situation. This study reports the different modes of presentations and treatment results. We reviewed 21 cases of penile fracture over 5 years. Parameters were mode of injury, age group, time interval before presentation, management, site of injury, urethral involvement, results, complications and erectile function at follow-up. The mean age of patients was 34 years, the mean time interval until presentation was 26 h. Cases involving the right corpus cavernosum comprised 57.14% and 42.85% were cases involving the left corpus cavernosum. Two patients had full circumferential urethral tear. Two patients developed wound infections and 2 patients developed mild penile curvature (40 h). Urologists need to consider penile fracture a urological emergency and atypical presentations need to be considered when deciding on management. © 2017 S. Karger AG, Basel.

  3. Fracture as a material sink (United States)

    Volokh, K. Y.


    Cracks are created by massive breakage of molecular or atomic bonds. The latter, in its turn, leads to the highly localized loss of material, which is the reason why even closed cracks are visible by a naked eye. Thus, fracture can be interpreted as the local material sink. Mass conservation is violated locally in the area of material failure. We consider a theoretical formulation of the coupled mass and momenta balance equations for a description of fracture. Our focus is on brittle fracture and we propose a finite strain hyperelastic thermodynamic framework for the coupled mass-flow-elastic boundary value problem. The attractiveness of the proposed framework as compared to the traditional continuum damage theories is that no internal parameters (like damage variables, phase fields, etc.) are used while the regularization of the failure localization is provided by the physically sound law of mass balance.

  4. Bone shortening of clavicular fractures

    DEFF Research Database (Denmark)

    Thorsmark, A. H.; Muhareb Udby, P.; Ban, I.


    Background: The indication for operative treatment of clavicular fractures with bone shortening over 2 cm is much debated. Correct measurement of clavicular length is essential, and reliable measures of clavicular length are therefore highly requested by clinical decision-makers. The aim...... of this study was to investigate if three commonly scientifically used measurement methods were interchangeable to each other. Methods: A retrospective study using radiographs collected as part of a previous study on clavicular fractures. Two independent raters measured clavicle shortening on 60 patients using......, Weir's protocol for Standard error of measurement (SEM) and minimal detectable change (MDC), and Bland-Altman plots. Results: None of the methods were directly interchangeable. The side difference method by Lazarides et al. was the most reliable of the three methods, but had a high proportion of post-fracture...

  5. Infrared thermal imaging in the diagnosis of musculoskeletal injuries: a systematic review and meta-analysis. (United States)

    Sanchis-Sánchez, Enrique; Vergara-Hernández, Carlos; Cibrián, Rosa M; Salvador, Rosario; Sanchis, Enrique; Codoñer-Franch, Pilar


    Musculoskeletal injuries occur frequently. Diagnostic tests using ionizing radiation can lead to problems for patients, and infrared thermal imaging could be useful when diagnosing these injuries. A systematic review was performed to determine the diagnostic accuracy of infrared thermal imaging in patients with musculoskeletal injuries. A meta-analysis of three studies evaluating stress fractures was performed and found a lack of support for the usefulness of infrared thermal imaging in musculoskeletal injuries diagnosis.

  6. Effect of heat treatment on the fracture behaviour of directionally solidified (gamma/gamma-prime)-alpha alloy (United States)

    Sriramamurthy, A. M.; Tewari, S. N.


    An investigation is conducted into the influence of various heat treatments on the work of fracture and its relation to microstructure for a directionally solidified Ni-33Mo-5.7Al (wt pct) (gamma/gamma-prime)-alpha alloy. The jagged crack propagation observed is due to delamination of the ligaments and associated plastic deformation. Fracture behavior is examined with respect to alloy microstructures and load-deflection curves. The four heat-treatment conditions considered are: (1) as-directionally solidified, (2) solutionized, (3) directionally solidified and thermally cycled, and (4) solutionized and thermally cycled.

  7. [Vertical fractures: apropos of 2 clinical cases]. (United States)

    Félix Mañes Ferrer, J; Micò Muñoz, P; Sánchez Cortés, J L; Paricio Martín, J J; Miñana Laliga, R


    The aim of the study is to present a clinical review of the vertical root fractures. Two clinical cases are presented to demonstrates the criteria for obtaining a correct diagnosis of vertical root fractures.

  8. Avulsion Fracture: How Is It Treated? (United States)

    ... is the best way to treat an avulsion fracture in a young athlete? Answers from Edward R. Laskowski, M.D. Treatment of an avulsion fracture typically includes resting and icing the affected area, ...

  9. Fracture Fluid Additive and Formation Degradations (United States)

    This presentation is on reactions that describe the degradation of fracturing fluids & formations during the hydraulic fracturing process & the clean‐up period. It contains a description of primary chemical reaction controls, & common degradation reactions

  10. [Development and application of fracture risk assessments]. (United States)

    Nakamura, Toshitaka


    Definition of osteoporosis by BMD T-score has been accepted globally. However, the age-dependent changes in BMD values differ on the different sites for measurements and the sensitivity of BMD to predict the risk of osteoporotic fracture, assessed by the risk gradient value, is as small as 1.7. Reportedly, WHO Fracture Risk Assessment (FRAX®) tool to compute 10-year probabilities of osteoporotic fracture, is sensitive enough to select the high fracture risk subjects with the risk gradient value of 2.57 - 2.77 in Japanese men and women. The combination of the three major risk factors such as age, BMD and prevalent fractures, when both morphometric spine and clinical non-spine fracture are included, represents the value of 2.49 - 2.71. Radiographic assessment of prevalent vertebral fracture, along with FRAX®evaluation, seems to be important in assessing the fracture risk in Japanese subjects.

  11. Percutanous vertebroplasty for vertebral compression fracture in ...

    African Journals Online (AJOL)

    ; a report of two cases. ... Background: Osteoporotic vertebral fractures are common in the geriatric age group. ... Conclusion: Percutanous vertebroplasty offers effective, immediate and sustained pain relief in osteoporotic vertebral fractures.

  12. Non-union in forearm fractures

    National Research Council Canada - National Science Library

    Jayakumar, P; Jupiter, J B


    Non-union in forearm fractures is an uncommon but complex problem. This is especially given the unique anatomical structure and function of the forearm, making treatment distinctly different to that of other long bone fractures...

  13. [Pilon fractures : Review of diagnostics and classification]. (United States)

    Wiebking, U


    Intraarticular fractures of the distal tibia (pilon fractures) are rare injuries and today they occur mostly in traffic accidents and falls from a great height. There are simple fractures in the context of low-energy traumas, as well as complex comminuted fractures in high-energy traumas. Besides the clinical examination, plain radiographs and computed tomographic scans are diagnostic prerequisites. The aim of the diagnostic process is to clearly identify and classify the fracture before appropriate treatment is initiated. The systems used to classify the displaced distal pilon fractures are supposed to ensure the three-dimensional assessment of the fracture and provide high inter- and intra-observer agreement. In addition to the classification of Rüedi and Allgöwer, the classification of pilon fractures has been carried out using the AO classification.

  14. Pelvic fractures: classification and nursing management. (United States)

    Walker, Jennie

    Fractures to the pelvis can occur as a result of low-energy or high-energy trauma. Pelvic fractures may be associated with significant internal bleeding and injury to the organs within the pelvis. Patients with pelvic fractures often have complex healthcare needs; fractures resulting from high-energy trauma may be associated with multiple injuries, whereas fractures resulting from low-energy trauma, such as falls, may be associated with multiple patient comorbidities. Nurses have a fundamental role in the assessment and observation of the patient following pelvic fracture and are crucial in identifying any changes or deterioration in the patient's condition that require prompt intervention. This article focuses on the relevant anatomy of the pelvis, epidemiology and classification of pelvic fractures, and outlines the management and complications of pelvic fractures.

  15. Oblique angled view for coracoid fractures. (United States)

    Goldberg, R P; Vicks, B


    In cases of shoulder injury when clinical signs suggest a possible coracoid fracture, a 20 degree posterior oblique film with 20 degrees of cephalad angulation has been shown to demonstrate coracoid fractures when other views have been inconclusive.

  16. Oblique angled view for coracoid fractures

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, R.P.; Vicks, B.


    In cases of shoulder injury when clinical signs suggest a possible coracoid fracture, a 20 degree posterior oblique film with 20 degrees of cephalad angulation has been shown to demonstrate coracoid fractures when other views have been inconclusive.

  17. A retrospective analysis of zygomatic fracture etiologies

    Directory of Open Access Journals (Sweden)

    Yoshiaki Sakamoto


    Conclusion: The severities of the zygomatic fractures, their causes, and the associated patient ages were closely related. Based on this study, possible prevention strategies for zygomatic fractures need to be considered.

  18. Hydrogen fracture toughness tester completion

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.

  19. Trapezoid fracture caused by assault

    Directory of Open Access Journals (Sweden)

    Malshikare V


    Full Text Available In this report we describe an open fracture of trapezoid and break in anterior cortex of capitate due to assault in a young adult male. Direct impact force of a sharp object to the first web space caused the above fractures. Open reduction and internal fixation of the trapezoid was carried out using Kirschner wires. Cut extensor tendons, extensor retaniculum, capsule, adductor pollicis muscle, first dorsal interosseous muscle, soft tissue and overlying skin were sutured primarily. Three months after the operation the patient has made a complete recovery. There is no similar case reported in the literature.

  20. Dynamic fracture of heterogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Stout, M.G.; Liu, C.; Addessio, F.L.; Williams, T.O.; Bennett, J.G.; Haberman, K.S.; Asay, B.W.


    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to investigate the fundamental aspects of the process of dynamic fracture propagation in heterogeneous materials. The work focused on three important, but poorly understood, aspects of dynamic fracture for materials with a heterogeneous microstructure. These were: the appropriateness of using a single-parameter asymptotic analysis to describe dynamic crack-tip deformation fields, the temperature rises at the tip and on the flanks of a running crack, and the constitutive modeling of damage initiation and accumulation.

  1. Probabilistic Simulation for Nanocomposite Fracture (United States)

    Chamis, Christos C.


    A unique probabilistic theory is described to predict the uniaxial strengths and fracture properties of nanocomposites. The simulation is based on composite micromechanics with progressive substructuring down to a nanoscale slice of a nanofiber where all the governing equations are formulated. These equations have been programmed in a computer code. That computer code is used to simulate uniaxial strengths and fracture of a nanofiber laminate. The results are presented graphically and discussed with respect to their practical significance. These results show smooth distributions from low probability to high.

  2. Metacarpal fractures in the athlete. (United States)

    Soong, Maximillian; Chase, Samantha; George Kasparyan, N


    To describe current evaluation and treatment of metacarpal fractures in athletes RECENT FINDINGS: Biomechanical and clinical studies involving lower-profile, locking, shorter length, and double-row or separate-dual plate configurations, as well as intramedullary screw fixation, have demonstrated the potential benefits of internal fixation with promising results. Treatment should be customized to the specific athlete and injury, and is often successful without surgery, or with percutaneous pin fixation. Internal fixation of metacarpal fractures has improved with new hardware and new techniques, and may expedite return to play, although further clinical studies are needed.

  3. In Situ Steam Fracture Experiments. (United States)


    an average tensile strength of 1.1 MPa, as measured by TerraTek. An overcore test performed by Fenix and Scisson in 1982, at the 1.05 meter to 1.21...acker 46 The source region had a 42-millidarcy value. Fenix and Scisson geologists (Reference 4) reported a visual fracture between Holes A and B. These...Tunnel, Neva- Test Site," SAND 80-1138, April 1981. 3. O’Brien, M. 8., "Results of Steam Hydraulic Fracture Drilling," Memo from Fenix and Scisson to J

  4. Quantifying Fracture Heterogeneity in Different Domains of Folded Carbonate Rocks to Improve Fractured Reservoir Analog Fluid Flow Models

    NARCIS (Netherlands)

    Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.


    Fluid flow in carbonate reservoirs is largely controlled by multiscale fracture networks. Significant variations of fracture network porosity and permeability are caused by the 3D heterogeneity of the fracture network characteristics, such as intensity, orientation and size. Characterizing fracture

  5. Rough and partially-cemented fracture permeability (United States)

    Landry, C. J.; Eichhubl, P.; Prodanovic, M.


    Numerical studies of mass transport in fractured rock, such as discrete fracture network models, use models to assign estimates of permeability to individual fractures. These fracture permeability models typically employ statistical moments of the fracture aperture distribution to estimate permeability. Although it is known that these fracture permeability models are in error, the quantification of this error is limited. We use a digital rock physics workflow to quantify this error in four fracture samples, a barren artificially-induced fracture in sandstone, a calcite-lined fracture sampled from outcrop, and two quartz-bridged fractures sampled from reservoir core. Each of the fracture samples is imaged using three-dimensional x-ray computed microtomography. The images are then processed, segmented and used in a lattice-Boltzmann-method-based flow simulation. We also vary the kinematic apertures of the barren and calcite-lined fractures through digital dilatation and closure in order to investigate sensitivity to the relative fracture roughness. We define the scalar error, F, between the actual permeability determined from simulation, kLB, and that predicted using the fracture permeability model of Zimmerman and Bodvarsson (1996), kZB, as, F±1=kZB/kLB. Although the pore space shape of the fractures appears quite different, the scalar error as a function of relative roughness is found to be similar for all fracture samples investigated, with a maximum of approximately 2. Considering two-dimensional cross-sections of fractures are more readily available than three-dimensional images we then plot the scalar error as a function of relative roughness and the number of observations measured from two-dimensional images (width of fracture analyzed). In general, the rougher the fracture, the greater the number of observations that are required to define the statistical moment inputs for the fracture permeability model. We use these results to approximate the width of the

  6. Sensitivity of the active fracture model parameter to fracture network orientation and injection scenarios (United States)

    Başağaoğlu, Hakan; Succi, Sauro; Manepally, Chandrika; Fedors, Randall; Wyrick, Danielle Y.


    Active fractures refer to the portions of unsaturated, connected fractures that actively conduct water. The active fracture model parameter accounts for the reduction in the number of fractures carrying water and in the fracture-matrix interface area in field-scale simulations of flow and transport in unsaturated fractured rocks. One example includes the numerical analyses of the fault test results at the Yucca Mountain site, Nevada (USA). In such applications, the active fracture model parameter is commonly used as a calibration parameter without relating it to fracture network orientations and infiltration rates. A two-dimensional, multiphase lattice-Boltzmann model was used in this study to investigate the sensitivity of the active fracture model parameter to fracture network orientation and injection scenarios for an unsaturated, variable dipping, and geometrically simple fracture network. The active fracture model parameter differed by as much as 0.11-0.44 when the effects of fracture network orientation, injection rate, and injection mode were included in the simulations. Hence, the numerical results suggest that the sensitivity of the active fracture model parameter to fracture network orientation, injection rates, and injection modes should be explored at the field-scale to strengthen the technical basis and range of applicability of the active fracture model.

  7. Fracture Union in Closed Interlocking Nail in Femoral Fracture

    Directory of Open Access Journals (Sweden)

    R L Sahu


    Full Text Available INTRODUCTION: Fractures shaft femur is a major cause of morbidity and mortality in patients with lower extremity injuries. The objective of this study was to find out the outcome of Interlocking nail in fracture femur. METHODS: This study was conducted in the Department of Orthopaedic surgery in M. M. Medical College from July 2006 to November 2008. Seventy eight patients were recruited from Emergency and out patient department having closed fracture of femoral shaft. All patients were operated under general or spinal anesthesia. All patients were followed for nine months. RESULTS: Out of seventy eight patients, sixty nine patients underwent union in 90 to 150 days with a mean of 110.68 days. Touch down weight bearing was started on 2nd post-operative day. Complications found in four patients who had non-union, and five patients had delayed union which was treated with dynamization and bone graft. The results were excellent in 88.46% and good in 6.41% patients. CONCLUSIONS: We concluded that this technique is advantageous because of early mobilization (early weight bearing, less complication with good results and is economical. Keywords: close reamed interlocking nail, dynamization, femoral shaft fractures, union

  8. Fracture Rates and Fracture Sites in Patients With Osteogenesis Imperfecta

    DEFF Research Database (Denmark)

    Folkestad, Lars; Hald, Jannie Dahl; Ersbøll, Annette Kjaer


    Osteogenesis imperfecta (OI) is a hereditary, clinically heterogeneous, connective tissue disorder. The population prevalence of OI in Denmark is 10.6 in 100,000. A hallmark of the disease is frequent fractures that are often precipitated by minimal trauma. The aim of the current study...

  9. Pedicular stress fracture in the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Chong, V.F.H.; Htoo, M.M. [Singapore General Hospital, Singapore, (Singapore). Department of Diagnostic Radiology


    Spondylolisthesis with or without spondylolysis is common in the lumbar spine. Associated fracture in the pedicle (`pediculolysis`) is unusual. The margins of pedicular stress fractures, like spondylolysis, usually appear sclerotic. A patient with a pedicular stress fracture with minimal marginal sclerosis suggesting an injury of recent onset is presented here. There was associated bilateral spondylolysis. The findings in this patient suggest that established pediculolysis probably represents a stress fracture that has failed to heal. (authors). 10 refs., 2 figs.

  10. Treatment of neglected femoral neck fracture


    Jain, Anil K; Mukunth, R; Srivastava, Amit


    Intra-capsular femoral neck fractures are seen commonly in elderly people following a low energy trauma. Femoral neck fracture has a devastating effect on the blood supply of the femoral head, which is directly proportional to the severity of trauma and displacement of the fracture. Various authors have described a wide array of options for treatment of neglected/nonunion (NU) femoral neck fracture. There is lack of consensus in general, regarding the best option. This Instructional course ar...

  11. Current Concepts in Paediatric Femoral Shaft Fractures (United States)

    John, Rakesh; Sharma, Siddhartha; Raj, Gopinathan Nirmal; Singh, Jujhar; C., Varsha; RHH, Arjun; Khurana, Ankit


    Pediatric femoral shaft fractures account for less than 2% of all fractures in children. However, these are the most common pediatric fractures necessitating hospitalization and are associated with prolonged hospital stay, prolonged immobilization and impose a significant burden on the healthcare system as well as caregivers. In this paper, the authors present a comprehensive review of epidemiology, aetiology, classification and managemement options of pediatric femoral shaft fractures. PMID:28603567

  12. Flowback patterns of fractured shale gas wells

    Directory of Open Access Journals (Sweden)

    Naizhen Liu


    Full Text Available Shale gas reservoirs generally need to be fractured massively to reach the industrial production, however, the flowback ratio of fractured shale gas wells is low. In view of this issue, the effects of natural fracture spacing, fracture conductivity, fracturing scale, pressure coefficient and shut-in time on the flowback ratio were examined by means of numerical simulation and experiments jointly, and the causes of flowback difficulty of shale gas wells were analyzed. The results show that the flowback ratio increases with the increase of natural fracture spacing, fracture conductivity and pressure coefficient and decreases with the increase of fracturing scale and shut-in time. From the perspective of microscopic mechanism, when water enters micro-cracks of the matrix through the capillary self-absorbing effect, the original hydrogen bonds between the particles are replaced by the hydroxyl group, namely, hydration effect, giving rise to the growth of new micro-cracks and propagation of main fractures, and complex fracture networks, so a large proportion of water cannot flow back, resulting in a low flowback ratio. For shale gas well fracturing generally has small fracture space, low fracture conductivity and big fracturing volume, a large proportion of the injected water will be held in the very complex fracture network with a big specific area, and unable to flow back. It is concluded that the flowback ratio of fractured shale gas wells is affected by several factors, so it is not necessary to seek high flowback ratio deliberately, and shale gas wells with low flowback ratio, instead, usually have high production.

  13. Subtrochanteric femur fracture after removal of screws for femoral neck fracture in a child. (United States)

    Song, Kwang Soon; Lee, Si Wook


    Displaced femoral neck fractures are rare in children and are associated with a high rate of complications. Subtrochanteric fractures after cannulated screw fixation of femoral neck fractures in adults are well recognized, and there are several reports on the topic. However, there are no reports on complications related to hardware or subtrochanteric fractures after removal of the screws in the treatment of femoral neck fractures in children. Here we report the case of a 10-year-old boy who sustained a subtrochanteric fracture after the screw removal and healing that followed a femoral neck fracture.

  14. Evolution of Induced Seismicity in Response to Injection into Fractured Reservoirs (United States)

    Elsworth, D.; Izadi, G.; Zheng, B.; Gan, Q.; Taron, J.


    The evolution of permeability, heat and diffusive or reactive transfer area and induced seismicity are intimately linked in forced-circulation systems such as EGS, CCS and unconventional hydrocarbon reservoirs where conditions are pushed far-from-equilibrium. We explore this evolution subject to coupled thermo-hydraulic-mechanical-chemical (THMC) processes in prototypical reservoirs that contain distributions of faults and fractures in separate populations. We accommodate the influence of early-time changes in effective stress, mid-time changes in thermal stresses and ultimately incorporate long-term changes due to chemical effects which also influence the stress field and drive the reservoir either towards or away from failure. We develop a micromechanical model to represent the failure process and apply this model to represent energy release from individual critically oriented fractures. The changing stress state is calculated from the pore pressure, thermal drawdown and chemical effects for a coupled THMC model with dual porosity. This model is applied to explore the spatial and temporal migration for permeability evolution, access to reactive surface area and the triggering of seismicity as injection proceeds. Seismic activity is initially concentrated around the near-wellbore injection region. It is earliest for closely spaced fractures in reservoir rocks where the thermal drawdown of stress is largest at early times and results in numerous low-magnitude events. These observations are used to define the evolution of spatial changes within the reservoir and their migration with time as shear failure on relic fractures mobilized.

  15. Fracture load and failure types of different veneered polyetheretherketone fixed dental prostheses. (United States)

    Taufall, Simon; Eichberger, Marlis; Schmidlin, Patrick R; Stawarczyk, Bogna


    The aim of this study is to investigate the fracture load of different veneered PEEK 3-unit fixed dental prosthesis (FDPs) after different aging regimens. Congruently anatomically shaped 3-unit FDPs were milled using a master stl-data set and randomly divided into four groups (N = 120, n = 30 per veneering group), which were veneered using different veneering methods: (i) digital veneering with breCAM.HIPC, (ii) conventional veneering with crea.lign, (iii) conventional with crea.lign paste, and (iv) using pre-manufactured veneers visio.lign. The FDPs were then adhesively cemented on a metal abutment and fracture loads were measured in a universal testing machine (1 mm/min) before and after aging (10,000 thermal cycles, 5/55 °C). Two- and one-way ANOVA followed by post hoc Scheffé tests were used for data analysis (p veneering method on the fracture load results independent of the aging level. The highest fracture load was measured for the FDPs with digital veneering (1882 ± 152 N at baseline, 2021 ± 184 N after thermocycling). The remaining groups showed comparable results, and no impact of thermal aging was observed. Digital and conventional veneers showed cracks in the pontic region starting from the connector area as a main failure type after loading, while the pre-manufactured veneers showed predominantly adhesive failures. The digital veneering method showed the highest fracture load resistance. Thermal aging showed no impact on the fracture load of all tested veneered PEEK 3-unit FDPs. According to this study results, reliable veneering of PEEK FDPs can be achieved with digital veneering.

  16. Recommendations for the shallow-crack fracture toughness testing task within the HSST (Heavy-Section Steel Technology) Program

    Energy Technology Data Exchange (ETDEWEB)

    Theiss, T.J. (Oak Ridge National Lab., TN (USA))


    Recommendations for Heavy-Section Steel Technology Program's investigation into the influence of crack depth on the fracture toughness of a steel prototypic of those in a reactor pressure vessel are included in this report. The motivation for this investigation lies in the fact that probabilistic fracture mechanics evaluations show that shallow flaws play a dominant role in the likelihood of vessel failure, and shallow-flaw specimens have exhibited an elevated toughness compared with conventional deep-notch fracture toughness specimens. Accordingly, the actual margin of safety of vessels may be greater than that predicted using existing deep-notch fracture-toughness results. The primary goal of the shallow-crack project is to investigate the influence of crack depth on fracture toughness under conditions prototypic of a reactor vessel. A limited data base of fracture toughness values will be assembled using a beam specimen of prototypic reactor vessel material and with a depth of 100 mm (4 in.). This will permit comparison of fracture-toughness data from deep-cracked and shallow-crack specimens, and this will be done for several test temperatures. Fracture-toughness data will be expressed in terms of the stress-intensity factor and crack-tip-opening displacement. Results of this investigation are expected to improve the understanding of shallow-flaw behavior in pressure vessels, thereby providing more realistic information for application to the pressurized-thermal shock issues. 33 refs., 17 figs.

  17. Concomitant hip and distal radius fractures

    Directory of Open Access Journals (Sweden)

    Yi-Pin Lin


    Conclusion: Concomitant hip and distal radius fractures were generally ipsilateral and involved the femoral neck after a backward fall. These patients were younger than and not more osteoporotic than the population with isolated hip fractures; however, the hospital stay was significantly increased. The functional outcome was not influenced by concomitant wrist fracture.

  18. Functional outcome after a spinal fracture

    NARCIS (Netherlands)

    Post, Richard Bernardus


    This thesis takes a closer look at the functional outcome after a spinal fracture. An introduction to different aspects regarding spinal fractures is presented in Chapter 1. The incidence of traumatic thoracolumbar spinal fractures without neurological deficit in the Netherlands is approximately 1.2

  19. Facts and fiction in hip fracture treatment

    NARCIS (Netherlands)

    Embden, Daphne van


    As the number of hip fracture patients has increased dramatically over the years, the need for high quality, multidisciplinary and patient centred fracture treatment continues to grow. The first aim of this thesis is to provide better understanding of fracture patterns and classification in hip

  20. Management of pediatric mandibular fracture using orthodontic ...

    African Journals Online (AJOL)

    Fractures of the mandible are relatively less frequent in children when compared to adults. The anatomic features of children are protected. Children have a higher adaptation to maxillofacial fractures compared to adults. Treatment principles of mandibular fractures in children differ from that of adults due to concerns ...

  1. Hydraulic fracturing with distinct element method

    NARCIS (Netherlands)

    Pruiksma, J.P.; Bezuijen, A.


    In this report, hydraulic fracturing is investigated using the distinct element code PFC2D from Itasca. Special routines were written to be able to model hydraulic fracturing. These include adding fluid flow to PFC2D and updating the fluid flow domains when fractures appear. A brief description of

  2. Fractures in infants and toddlers with rickets

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Teresa; Done, Stephen [Seattle Children' s Hospital, Department of Radiology, Seattle, WA (United States); Sugar, Naomi; Feldman, Kenneth [Seattle Children' s Hospital, Children' s Protection Program, Seattle, WA (United States); Marasigan, Joanne; Wambold, Nicolle [University of Washington, College of Arts and Sciences, Seattle, WA (United States)


    Rickets affects young infants and toddlers. However, there is a paucity of literature regarding the types of fractures that occur in rachitic patients. To evaluate the age of patients at which radiographically evident rickets occurs, and to characterize the age incidence and fractures that are observed in infants and toddlers with radiographically evident rickets. A retrospective study of children younger than 24 months was performed. Clinical data and radiographs were reviewed. Radiographs obtained within 1 month of the diagnosis were evaluated for the presence or absence of osteopenia, presence or absence of fraying-cupping, and presence and characterization of fractures. After exclusion criteria were applied, 45 children were included in the study. Children with rickets evident by radiograph were in the age range of 2-24 months. Fractures were present in 17.5% of the study group, exclusively in mobile infants and toddlers. Fracture types included transverse long bone fractures, anterior and anterior-lateral rib fractures, and metaphyseal fractures. All fractures occurred exclusively in patients with severe, overtly evident rickets. Fractures occur in older infants and toddlers with overt rickets and can be seen by radiograph. Fractures do not resemble high-risk non-accidental trauma fractures. (orig.)

  3. Traumatic Foot Fractures in Hard Working Donkeys

    Directory of Open Access Journals (Sweden)

    M.A. Semieka


    Full Text Available The present study was carried out on 45 hard working donkeys suffering from different types of traumatic foot fractures. These animals were selected from the clinical cases admitted to the Veterinary Teaching Hospital, Assiut University during the period of 2007-2010. Based on history, clinical signs and radiographic examination, various types of traumatic foot fractures were diagnosed and recorded. These fractures were affect metacarpal bones (N. =16, metatarsal bones (N. =9, proximal phalanx (N. = 13, middle phalanx (N. = 3, distal phalanx (N. = 2 and proximal sesamoid bones (N. = 2. It could be concluded that fractures of the large metacarpal bones are the most common types followed by fractures of the proximal phalanx of the thoracic limb then fractures of the metatarsal bones. Fractures of the middle phalanx, distal phalanx and proximal sesamoid bone are less common in donkeys. Single fractures of the metacarpal and metatarsal bones are more common than comminuted one, in addition diaphyseal fractures of these bones are more common than metaphyseal or epiphyseal fractures. In the proximal phalanx, comminuted fractures are more common than single fractures.


    African Journals Online (AJOL)


    Jan 2, 1971 ... BRONCHIAL FRACTURE FOLLOWING BLUNT CHEST TRAUMA*. J. F. HITCHCOCK, M.B., CH.B., M.MED. (SURG.), Department of Cardiolhoracic SlIrger.\\", Croote Schllllr Hospilal,. Cape Town. Fractures of the trachea or major bronchi are becoming increasingly common. in particu:ar fractures of one or.

  5. Evaluation of regional fracture properties for groundwater ...

    Indian Academy of Sciences (India)

    governing the spatial distribution of these fracture systems are computed using a software-based model. As an exemplar .... spread throughout the domain, indicating a central tendency of data .... 523. Table 1. Fracture statistics of the studied hydrostructural and hydrolithostructural domains showing fracture frequency and.

  6. Biodegradable interlocking nails for fracture fixation

    NARCIS (Netherlands)

    van der Elst, M.; Bramer, J. A.; Klein, C. P.; de Lange, E. S.; Patka, P.; Haarman, H. J.


    Serious problems such as stress shielding, allergic reactions, and corrosion are associated with the use of metallic fracture fixation devices in fractured long bones. Metal implants often are removed during a second retrieval operation after fracture healing has completed. A biocompatible implant

  7. Phalangeal bone mineral density predicts incident fractures

    DEFF Research Database (Denmark)

    Friis-Holmberg, Teresa; Brixen, Kim; Rubin, Katrine Hass


    This prospective study investigates the use of phalangeal bone mineral density (BMD) in predicting fractures in a cohort (15,542) who underwent a BMD scan. In both women and men, a decrease in BMD was associated with an increased risk of fracture when adjusted for age and prevalent fractures...

  8. Tips and Tricks in Mallet Fracture Fixation. (United States)

    Chin, Yuin Cheng; Foo, Tun-Lin


    We describe three steps to aid fracture assessment and fixation in the extensor block pin technique for mallet fractures. The first step is the use of fluoroscopy in the initial assessment to determine indication for fixation. Next is the use of supplementary extension block pin to control larger dorsal fragments. The third technique described details the steps of open reduction of nascently malunited fractures.

  9. 49 CFR 195.111 - Fracture propagation. (United States)


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Fracture propagation. 195.111 Section 195.111... PIPELINE Design Requirements § 195.111 Fracture propagation. A carbon dioxide pipeline system must be designed to mitigate the effects of fracture propagation. [Amdt. 195-45, 56 FR 26926, June 12, 1991] ...

  10. How to implement a fracture liaison service (United States)

    The case for Fracture Liaison Service (FLS) for the prevention of secondary fractures is clear. With an ageing population, the burden of osteoporosis is set to increase. Despite evidence for the clinical effectiveness of secondary fracture prevention, translation in the real world setting remains di...


    Hydraulic fracturing is a physical process that creates fractures in silty clay soil to enhance its permeability. The technology, developed by the Risk Reduction Engineering Laboratory (RREL) and the University of Cincinnati, creates sand-filled horizontal fractures up to 1 in. i...

  12. Subtrochanteric fractures in bisphosphonate-naive patients

    DEFF Research Database (Denmark)

    Adachi, Jonathan D; Lyles, Kenneth; Boonen, Steven


    Our purpose was to characterize the risks of osteoporosis-related subtrochanteric fractures in bisphosphonate-naive individuals. Baseline characteristics of patients enrolled in the HORIZON-Recurrent Fracture Trial with a study-qualifying hip fracture were examined, comparing those who sustained ...

  13. Fracture resistance of endodontically treated teeth: effect of tooth coloured post material and surface conditioning. (United States)

    Toman, Muhittin; Toksavul, Suna; Sarikanat, Mehmet; Nergiz, Ibrahim; Schmage, Petra


    This in vitro study evaluated the effects of the different endodontic posts and surface conditioning on the fracture resistance and fracture modes of endodontically treated teeth. The experimental groups consisted of zirconia ceramic post with a glasss-ceramic core [A], zirconia ceramic post with a composite core [B], glass fiber composite post (FRC) with a composite core [C], and titanium post with a composite core [D]. All posts in these groups were cemented with self-adhesive resin cement (Rely X Unicem Aplicap) combination with tribochemical silica coating (TSC). Groups E, F, G and H comprised the same post-and-core materials as the first 4 groups but cemented with the same resin cement without TSC. Specimens were subjected to thermal cycling between 5 degrees C and 55 degrees C for a total of 5000 cycles with 30s per cycle. Static load was applied to the palatal surface of each specimen until they were fractured. Statistical analysis was conducted using analysis of variance (ANOVA) followed by post-hoc comparisons (Tukey). The fracture resistance was significantly affected by the post material (P surface conditioning (P post surface decreased the fracture resistance of zirconia ceramic post with composite core (p=0.002; Tukey) and glass FRC post with composite core (p=0.029; Tukey). No catastrophic failure was observed for groups B, C, D, E, F and G. Under the testing conditions used, the titanium post/composite core that had been silicoated exhibited the highest fracture resistance.

  14. Bovine xenograft application for treatment of a metatarsal nonunion fracture in an alpaca (Vicugna pacos). (United States)

    Longo, F; Finotti, L; Bellini, L; Zavan, B; Busetto, R; Isola, M


    A 15-year-old female huacaya alpaca (Vicugna pacos) was referred because of a non-weight-bearing lameness (4/4) in the left pelvic limb caused by a grade three open metatarsal fracture. The referring veterinarian treated the fracture with conservative management using bandages, but it progressively evolved to a non-union. Clinical examination revealed external wounds on the medial and lateral surfaces of the metatarsus. Radiographs confirmed an open, nonarticular, displaced, diaphyseal fracture of the left metatarsus. Cancellous bone was sourced from bovine proximal and distal femur epiphyses, followed by a thermal shock procedure to achieve decellularisation, to produce a xenograft. Open reduction and internal fixation of the fracture using locking plates was performed. Alignment of the fracture fragments was corrected and the xenograft was placed at the debrided fracture site to stimulate and harness osteogenesis in situ. Clinical and radiographic follow-up was performed up to 40 weeks postoperatively. Clinical evaluations revealed that the alpaca gradually increased weight bearing following bandage removal 10 days after surgery. Serial radiographs showed correct alignment of the left metatarsus, progressive bone modelling and, complete bone union at 12 weeks. Ten months postoperatively the alpaca showed no signs of lameness and resumed normal activity. For management of a metatarsal non-union, a combination of bovine xenograft application and angular stable internal fixation progressed toward an excellent long-term recovery.

  15. Hydraulic fracturing system and method

    Energy Technology Data Exchange (ETDEWEB)

    Ciezobka, Jordan; Maity, Debotyam


    A hydraulic fracturing system and method for enhancing effective permeability of earth formations to increase hydrocarbon production, enhance operation efficiency by reducing fluid entry friction due to tortuosity and perforation, and to open perforations that are either unopened or not effective using traditional techniques, by varying a pump rate and/or a flow rate to a wellbore.

  16. Penis Fracture: Is It Possible? (United States)

    ... occur when there is trauma to an erect penis. During an erection, the penis is engorged with blood. If an ... of one of the two cylinders in the penis (corpus cavernosum) responsible for erections — resulting in a penis fracture. The trauma most ...

  17. Fractures of the Fifth Metatarsal (United States)

    ... a 5-digit zip code. Please enter a city or last name. Search Where do you hurt? Interactive Foot Diagram Toe and Metatarsal Fractures (Broken Toes) The structure of the foot is complex, consisting of bones, muscles, tendons and other soft tissues. Of the ...

  18. Keyhole Fracture of the Skull (United States)


    2LT Aaron M. Jackson, USA1 Contributors: 2LT Aaron M. Jackson, USA1; 2nd LT. Brett K. Searcey, USAF1; James G. Smirniotopoulos, M.D. 1; Col Les...keyhole fracture. Note the beveling of the “exit” component. Also note the shaded green arrow representing the force vector for the in-driven

  19. Social inequality and hip fracture

    DEFF Research Database (Denmark)

    Harvey, N. C.; Hansen, L.; Judge, A.


    Social inequality appears to be increasing in many countries. We explored whether risk of hip fracture was associated with markers of inequality and whether these relationships changed with time, using data from Danish Health Registries. Methods: All patients 60 years or older with a primary hip...

  20. Calcaneal fractures • In children

    African Journals Online (AJOL)


    Jul 15, 1989 ... pointed our that this reported incidence is possibly erroneously low in view of the subtle clinical and radiographic presentation of this injury. A history of trauma may not be forthcoming, and furthermore, the blow required to produce a fracture of calcaneum, especially in the younger child, may be surprisingly.

  1. [Navigation surgery and fracture treatment

    NARCIS (Netherlands)

    Schep, N.W.; Vugt, A.B. van


    During operative fracture treatment the surgeon depends on fluoroscopic or X-ray radiological images as well as CT scans or MRI scans. This means that the surgeon sees only images at a given moment. Continuous imaging is technically complex and is accompanied by considerable exposure to radiation.

  2. Sport-related maxillofacial fractures

    NARCIS (Netherlands)

    Ruslin, M.; Boffano, P.; ten Brincke, Y.J.D.; Forouzanfar, T.; Brand, H.S.


    Sports and exercise are important causes of maxillofacial injuries. Different types of sports might differ in frequency and type of fractures. The aim of the present study was to explore the possible relation between the types of sport practiced and the frequency and nature of the facial bone

  3. Mandibular condyle fractures : a consensus

    NARCIS (Netherlands)

    Bos, RRM; Booth, RPW; de Bont, LGM

    A consensus was obtained following a two-day international conference to review the management of mandibular condyle fractures. Whilst areas of disagreement still exist, there are many areas of agreement. It is hoped this editorial will stimulate debate leading to internationally accepted

  4. Hydraulic fracturing system and method (United States)

    Ciezobka, Jordan; Salehi, Iraj


    A hydraulic fracturing system and method for enhancing effective permeability of earth formations to increase hydrocarbon production, enhance operation efficiency by reducing fluid entry friction due to tortuosity and perforation, and to open perforations that are either unopened or not effective using traditional techniques, by varying a pump rate and/or a flow rate to a wellbore.

  5. Risk of hip fracture after osteoporosis fractures. 451 women with fracture of lumbar spine, olecranon, knee or ankle

    DEFF Research Database (Denmark)

    Lauritzen, J B; Lund, B


    In a follow-up study during 1976-1984, the risk of a subsequent hip fracture was investigated in women aged 60-99 years, hospitalized for the following fractures: lumbar spine (n 70), olecranon (n 52), knee (n 129) and ankle (n 200). Follow-up ranged from 0 to 9 years. Observation time of the 4...... different fractures were 241, 180, 469, and 779, person-years, respectively. In women aged 60-79 years with one of the following fractures the relative risk of a subsequent hip fracture was increased by 4.8 (lumbar spine), 4.1 (olecranon), 3.5 (knee) and 1.5 (ankle). The relative risk of hip fracture showed...... a tendency to level off 3 years after the primary fracture....

  6. Complications of Nasal Bone Fractures. (United States)

    Hwang, Kun; Yeom, Seung Han; Hwang, Suk Hyun


    The aim of this study was to perform a systematic review of the treatment of nasal bone fractures. The search terms ("nasal bone fracture" AND complication) and ("nasal bone fracture" AND [anosmia OR olfaction OR olfactory nerve OR smell]) and (anosmia AND ["nasal preparation" OR "nasal antiseptics"]) were used to search PubMed and SCOPUS. Of the 500 titles, 40 full papers were reviewed. One paper was excluded, and 3 mined papers were added. Ultimately, 12 papers were analyzed. The overall deformity rate was 10.4% ± 4.8%. No significant differences were found between patients who underwent closed reduction (14.7% ± 7.3%) and those who underwent open reduction (9.4% ± 4.4%), between those who underwent local anesthesia (5.8% ± 4.5%), and those who underwent general anesthesia (8.8% ± 3.8%), or between those who received timely treatment (5.7%) and those whose treatment was delayed (9.0%). Septal deviation occurred in 10.0% of patients as a sequela of nasal bone fracture. The nasal obstruction rate was 10.5% ± 5.3%. Fewer patients of nasal obstruction occurred in the open reduction patients (6.9% ± 4.4%) than in the closed reduction patients (15.2%). One patient of epiphora and 1 patient of diplopia were reportedAmong the 77 patients with nasal bone fractures, 29 (37.7% ± 11.3%) complained of olfactory disturbances. No significant associations were found between the type of fracture and the presence of olfactory disturbances. It is recommended for providers to explain to patients that approximately one-tenth of nasal bone fractures exhibit deformity, septal deviation, or nasal obstruction after surgery. Surgeons should take considerable care to avoid the olfactory mucosa during reduction surgery.

  7. Stress fracture of the pelvis and lower limbs including atypical femoral fractures-a review. (United States)

    Tins, Bernhard J; Garton, Mark; Cassar-Pullicino, Victor N; Tyrrell, Prudencia N M; Lalam, Radhesh; Singh, Jaspreet


    Stress fractures, that is fatigue and insufficiency fractures, of the pelvis and lower limb come in many guises. Most doctors are familiar with typical sacral, tibial or metatarsal stress fractures. However, even common and typical presentations can pose diagnostic difficulties especially early after the onset of clinical symptoms. This article reviews the aetiology and pathophysiology of stress fractures and their reflection in the imaging appearances. The role of varying imaging modalities is laid out and typical findings are demonstrated. Emphasis is given to sometimes less well-appreciated fractures, which might be missed and can have devastating consequences for longer term patient outcomes. In particular, atypical femoral shaft fractures and their relationship to bisphosphonates are discussed. Migrating bone marrow oedema syndrome, transient osteoporosis and spontaneous osteonecrosis are reviewed as manifestations of stress fractures. Radiotherapy-related stress fractures are examined in more detail. An overview of typical sites of stress fractures in the pelvis and lower limbs and their particular clinical relevance concludes this review. Teaching Points • Stress fractures indicate bone fatigue or insufficiency or a combination of these. • Radiographic visibility of stress fractures is delayed by 2 to 3 weeks. • MRI is the most sensitive and specific modality for stress fractures. • Stress fractures are often multiple; the underlying cause should be evaluated. • Infratrochanteric lateral femoral fractures suggest an atypical femoral fracture (AFF); endocrinologist referral is advisable.

  8. Siku DEM Simulations of Beaufort Sea-Ice Fracture Pattern. (United States)

    Kulchitsky, A. V.; Hutchings, J. K.; Johnson, J.; Velikhovskiy, G.


    Leads are fractures in the ice pack where exposed ocean surface increases heat and moisture fluxes to the atmosphere. These leads are the location of shear in the pack and during winter control the transport of ice around the Beaufort Gyre. Hence prediction of lead direction opening and shear is important in forecasting sea ice drift and weather. Regional ice pack deformation is related to the fracture patterns, and related shear zones. Hence climate models need to simulate these processes to simulate realistic sea-ice transport and mass balance. We have developed a new discrete element method (DEM) model of sea ice, Siku, to forecast lead patterns. Siku is the first sea ice DEM model that takes into account the spherical geometry of the Earth, and allows simulation ranging from basin scale to meter scale without nesting. We present simulations with 2.5km resolution in the Chukchi and Beaufort Seas, and 25-100km across the rest of the Arctic. The DEM has been shown to reproduce discontinuous dynamics that result in shear patterns in the ice cover. We evaluate these against observed fracture patterns in thermal band satellite imagery. Simulations with differing ice mechanics produce lead pattern differences that are used to evaluate the physical validity of proposed physics of ice-ice and ice-coast contact. We present simulations demonstrating a good match to observations and discuss the implications for continuum modeling, where predicted ice transport along the Alaskan coast is known to be too slow.

  9. Seasonal thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.


    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  10. Fundamentals of Thermal Expansion and Thermal Contraction


    Liu, Zi-Kui; Shang, Shun-Li; Wang, Yi


    Thermal expansion is an important property of substances. Its theoretical prediction has been challenging, particularly in cases the volume decreases with temperature, i.e., thermal contraction or negative thermal expansion at high temperatures. In this paper, a new theory recently developed by the authors has been reviewed and further examined in the framework of fundamental thermodynamics and statistical mechanics. Its applications to cerium with colossal thermal expansion and Fe3Pt with th...

  11. Effects of Water-Rock Interaction on Unsaturated Flow in Heterogeneous Fractured Rock (United States)

    Sonnenthal, E. L.; Spycher, N. F.; Haukwa, C. B.


    Evaluation of coupled thermal, hydrological, and chemical processes associated with the potential high-level nuclear waste repository at Yucca Mountain, NV require consideration of the effects of permeability heterogeneity on reaction-transport processes in unsaturated fractured tuff under boiling conditions. As a result of capillary suction in unsaturated flow systems, the effect of permeability heterogeneity on water-rock interaction can be markedly different than in saturated flow systems. If regions of lower fracture permeability correspond to narrower fracture apertures, the liquid saturation may be higher than in adjacent areas of higher permeability and larger fracture apertures. Spatial differences in liquid saturation within fractures, resulting from variations in capillary suction, affect reaction rates in a number of ways. Of primary importance to the overall reaction rate is the reactive surface area, which may diminish with decreasing liquid saturation - a relationship that is unknown apriori. The extent of reaction is also a function of the percolation flux that may be smaller in regions of higher absolute permeability but having lower relative permeability. However, diffusive and advective gaseous species transport may be enhanced in areas of low liquid saturation and high absolute permeability. Here we relate the reactive surface area to the fracture-matrix interaction area based on a modified form of the `Active Fracture Model' for flow in unsaturated fracture rock. Simulations included coupling between heat, water, and vapor flow, aqueous and gaseous species transport, kinetic and equilibrium mineral-water reactions, and feedback of mineral precipitation/dissolution on porosity, permeability, and capillary for a dual permeability (fracture-matrix) medium. Based on air-permeability measurements, 2-D heterogeneous fracture permeability fields were generated having a range of four orders of magnitude. Steady-state fracture liquid saturations, under

  12. Maxillofacial and Mandibular Fractures in Sports. (United States)

    Viozzi, Christopher F


    Sports account for 3% to 29% of facial injuries and 10% to 42% of facial fractures. Fractures of the facial skeleton most commonly occur owing to interpersonal violence or motor vehicle crashes. Facial fractures from sporting activities has clearly decreased over time owing to better preventive measures. However, this decreasing trend is offset by the emergence of more dangerous sports activities, or "pushing the envelope" of traditional sports activities. Fractures can occur from contact between athletes, and between athletes and their surroundings. Football, soccer, hockey, and baseball most frequently are involved in sports-related cases of facial bone fracture. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Geomechanical Simulation of Fluid-Driven Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Makhnenko, R.; Nikolskiy, D.; Mogilevskaya, S.; Labuz, J.


    The project supported graduate students working on experimental and numerical modeling of rock fracture, with the following objectives: (a) perform laboratory testing of fluid-saturated rock; (b) develop predictive models for simulation of fracture; and (c) establish educational frameworks for geologic sequestration issues related to rock fracture. These objectives were achieved through (i) using a novel apparatus to produce faulting in a fluid-saturated rock; (ii) modeling fracture with a boundary element method; and (iii) developing curricula for training geoengineers in experimental mechanics, numerical modeling of fracture, and poroelasticity.

  14. Pulsative hematoma: A penile fracture complication

    Directory of Open Access Journals (Sweden)

    Nale Đorđe


    Full Text Available Background. Fracture of the penis is a direct blunt trauma of the erect or semi-erect penis. It can be treated by conservative or surgical means. Retrospective analyses of conservative penile fracture treatment reveal frequent immediate and later complications. Case report. We presented a 41- year-old patient with pulsative hematoma caused by an unusual fracture of the penis. Fracture had appeared 40 days before the admittance during a sexual intercourse. The patient was treated surgically. Conclusion. Pulsative hematoma (pulsative diverticulum is a very rare, early complication of a conservatively treated penile fracture. Surgical treatment has an advantage over surgical one, which was confirmed by our case report.


    Energy Technology Data Exchange (ETDEWEB)

    Lam, P; Prof. Yuh J. Chao, P


    The meaning of the phrase 'constraint effect in fracture' has changed in the past two decades from 'contained plasticity' to a broader description of 'dependence of fracture toughness value on geometry of test specimen or structure'. This paper will first elucidate the fundamental mechanics reasons for the apparent 'constraint effects in fracture', followed by outlining a straightforward approach to overcoming this problem in both brittle (elastic) and ductile (elastic-plastic) fracture. It is concluded by discussing the major difference in constraint effect on fracture event in elastic and elastic-plastic materials.

  16. Prediction of Ductile Fracture Surface Roughness Scaling

    DEFF Research Database (Denmark)

    Needleman, Alan; Tvergaard, Viggo; Bouchaud, Elisabeth


    Experimental observations have shown that the roughness of fracture surfaces exhibit certain characteristic scaling properties. Here, calculations are carried out to explore the extent to which a ductile damage/fracture constitutive relation can be used to model fracture surface roughness scaling...... three dimensional stress and deformation states that develop in the fracture process region. An elastic-viscoplastic constitutive relation for a progressively cavitating plastic solid is used to model the material. Two populations of second phase particles are represented: large inclusions with low....... The scaling properties of the predicted thickness average fracture surfaces are calculated and the results are discussed in light of experimental observations....

  17. Geochemical controls on the kinetics of quartz fracture at subcritical tensile stresses (United States)

    Dove, Patricia M.


    A new kinetic model links physical and chemical controls on the subcritical fracture kinetics of quartz from the assumption that molecular level reactions governing fracture and dissolution proceed by similar pathways. The model formulation combines fracture theory with a mechanistically based description of chemical, thermal, and tensile stress effects on reactivity in aqueous environments. Water, as a vapor or liquid, promotes rupture of Si-O bonds by end-member processes: (1) reaction of a protonated surface with molecular water and (2) reaction of hydroxyl ions at an ionized surface. In humid environments, reaction frequency is determined by water accessibility to the crack tip. In wetted environments, the relative contributions of these mechanisms are determined by bulk solution composition which affects surface ionization and sol vent-surf ace interactions. The macroscopic fracture rate law is given in meters per second by the fractional sum of these end-member reaction mechanisms per a first-order equation. Agreement of this empirical rate expression with reported measurements of quartz fracture rates suggests the model is robust. It gives a good fit to fracture rates over 6 orders of magnitude and explains increasing rates with increasing solution pH, the dependence of rate upon crystallographic direction, and thermal dependence of rate over 20° to 80°C. Findings in this study suggest that (1) fracture models based upon changes in surface free energy with solution composition are macroscopic descriptions of solvent-surface interactions and parallel the mechanistic model presented here; (2) faster fracture rates observed in basic solutions are not facilitated by decreases in the activation barrier but are due to a transition in the solvent-surface reaction to give a higher reaction frequency and (3) power law expressions applied to fracture rate versus stress intensity measurements may not have direct mechanistic significance since log-linear relations

  18. Economic Analysis of Bisphosphonate Use after Distal Radius Fracture for Prevention of Hip Fracture

    Directory of Open Access Journals (Sweden)

    Suneel B. Bhat


    Full Text Available Background: Osteoporosis is a common condition among the elderly population, and is associated with an increased risk of fracture. One of the most common fragility fractures involve the distal radius, and are associated with risk of subsequent fragility fracture. Early treatment with bisphosphonates has been suggested to decrease the population hip fracture burden. However, there have been no prior economic evaluations of the routine treatment of distal radius fracture patients with bisphosphonates, or the implications on hip fracture rate reduction. Methods: Age specific distal radius fracture incidence, age specific hip fracture rates after distal radius fracture with and without risendronate treatment, cost of risendronate treatment, risk of atypical femur fracture with bisphosphonate treatment, and cost of hip fracture treatment were obtained from the literature. A unique stochastic Markov chain decision tree model was constructed from derived estimates. The results were evaluated with comparative statistics, and a one-way threshold analysis performed to identify the break-even cost of bisphosphonate treatment. Results: Routine treatment of the current population of all women over the age of 65 suffering a distal radius fracture with bisphosphonates would avoid 94,888 lifetime hip fractures at the cost of 19,464 atypical femur fractures and $19,502,834,240, or on average $2,186,617,527 annually, which translates to costs of $205,534 per hip fracture avoided. The breakeven price point of annual bisphosphonate therapy after distal radius fracture for prevention of hip fractures would be approximately $70 for therapy annually. Conclusion: Routine treatment of all women over 65 suffering distal radius fracture with bisphosphonates would result in a significant reduction in the overall hip fracture burden, however at a substantial cost of over a $2 billion dollars annually. To optimize efficiency of treatment either patients may be selectively

  19. Tibial Plateau Fracture Characteristics: Computed Tomography Mapping of Lateral, Medial, and Bicondylar Fractures. (United States)

    Molenaars, Rik J; Mellema, Jos J; Doornberg, Job N; Kloen, Peter


    Computed tomography (CT) is seen as a useful diagnostic modality in preoperative planning for tibial plateau fractures. The purpose of this study was to characterize patterns of tibial plateau fractures with use of CT mapping. We hypothesized that CT mapping of fractures of the tibial plateau would reveal recurrent patterns of fragments and fracture lines, including patterns that do not fit into Schatzker's original classification. One hundred and twenty-seven tibial plateau fractures were retrospectively included in this study. Fracture lines and zones of comminution were graphically superimposed onto an axial template of an intact subarticular tibial plateau to identify major patterns of fracture and comminution. This fracture map of the tibial plateau was subsequently divided into lateral (Schatzker types I, II, and III), medial (Schatzker type IV), and bicondylar (Schatzker types V and VI) fracture maps. This study included seventy-three female and fifty-four male patients (average age, forty-seven years [range, seventeen to ninety-one years]) with a tibial plateau fracture. Sixty-four of the fractures were Schatzker type I, II, or III; fifteen were Schatzker type IV; and forty-eight were Schatzker type V or VI. Analysis of the fracture maps suggested patterns in the Schatzker type-IV, V, and VI fractures beyond those described in Schatzker's original classification. The maps of the 127 fractures revealed four recurrent major fracture features: the lateral split fragment (A), found in 75%; the posteromedial fragment (B), seen in 43%; the tibial tubercle fragment (C), seen in 16%; and a zone of comminution that included the tibial spine and frequently extended to the lateral condyle (D), seen in 28%. Tibial plateau fracture maps show recurrent patterns of fracture lines, revealing four major fracture characteristics. An understanding of these recurrent features of tibial plateau fractures can aid surgeons during diagnosis, preoperative planning, and execution of

  20. Periprosthetic Fractures Following Total Knee Arthroplasty (United States)

    Kim, Nam Ki


    Periprosthetic fractures after total knee arthroplasty may occur in any part of the femur, tibia and patella, and the most common pattern involves the supracondylar area of the distal femur. Supracondylar periprosthetic fractures frequently occur above a well-fixed prosthesis, and risk factors include anterior femoral cortical notching and use of the rotational constrained implant. Periprosthetic tibial fractures are frequently associated with loose components and malalignment or malposition of implants. Fractures of the patella are much less common and associated with rheumatoid arthritis, use of steroid, osteonecrosis and malalignment of implants. Most patients with periprosthetic fractures around the knee are the elderly with poor bone quality. There are many difficulties and increased risk of nonunion after treatment because reduction and internal fixation is interfered with by preexisting prosthesis and bone cement. Additionally, previous soft tissue injury is another disadvantageous condition for bone healing. Many authors reported good clinical outcomes after non-operative treatment of undisplaced or minimally displaced periprosthetic fractures; however, open reduction or revision arthroplasty was required in displaced fractures or fractures with unstable prosthesis. Periprosthetic fractures around the knee should be prevented by appropriate technique during total knee arthroplasty. Nevertheless, if a periprosthetic fracture occurs, an appropriate treatment method should be selected considering the stability of the prosthesis, displacement of fracture and bone quality. PMID:25750888


    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi


    Numerical simulation of water injection in discrete fractured media with capillary pressure is a challenge. Dual-porosity models in view of their strength and simplicity can be mainly used for sugar-cube representation of fractured media. In such a representation, the transfer function between the fracture and the matrix block can be readily calculated for water-wet media. For a mixed-wet system, the evaluation of the transfer function becomes complicated due to the effect of gravity. In this work, they use a discrete-fracture model in which the fractures are discretized as one dimensional entities to account for fracture thickness by an integral form of the flow equations. This simple step greatly improves the numerical solution. Then the discrete-fracture model is implemented using a Galerkin finite element method. The robustness and the accuracy of the approach are shown through several examples. First they consider a single fracture in a rock matrix and compare the results of the discrete-fracture model with a single-porosity model. Then, they use the discrete-fracture model in more complex configurations. Numerical simulations are carried out in water-wet media as well as in mixed-wet media to study the effect of matrix and fracture capillary pressures.

  2. Noncontact plating technique in an open fracture (United States)

    Tuhanioğlu, Ümit; Oğur, Hasan Ulaş; Çiçek, Hakan; Seyfettinoğlu, Fırat; Çiloğlu, Osman; Kapukaya, Ahmet


    Aim In comparison with closed fractures, open fractures have an increased risk of infection, there are soft tissue-related problems, and difficulties are experienced in union. The aim of this study was to evaluate and discuss the results of osteosynthesis applied with a noncontact plate in Gustilo–Anderson Type 2, 3a, and 3b fractures. Method The study included 23 patients applied with debridement + noncontact plate osteosynthesis + soft tissue procedures in a single session for the treatment of an open fracture. A follow-up card was created to evaluate the patients in respect of age, gender, fracture level, fracture etiology, open fracture type, preoperative and postoperative sedimentation and C-reactive protein values, antibiotics used and duration of use, time to union, and complications. Results In all 23 patients, full bone union was obtained at mean 22.5 weeks (range: 16–36 weeks). Complications developed in 9 patients. Implant failure occurred in 3 patients. In 5 patients, infection developed which required repeated debridements. Conclusion In open fractures, noncontact plating following debridement seems to be a good alternative treatment method to intramedullar nailing, especially in metaphyseal and metaphyseo-diaphyseal fractures and in spiral oblique diafiz fractures. Noncontact plating may also be a good alternative to intramedullar nailing for open fracture treatment if the patients have additional pathologies such as contusion and thoracic injury. PMID:28652756

  3. Fractures in German elite male soccer. (United States)

    Schiffner, Erik; Latz, David; Grassmann, Jan P; Schek, Alberto; Scholz, Armin; Windolf, Joachim; Jungbluth, Pascal; Schneppendahl, Johannes


    Aim of this retrospective cohort study was to identify fracture epidemiology and off times after different types of fractures in German male elite soccer players from the first division Bundesliga based on information from the public media. Exposure and fracture data over 7.5 consecutive seasons (2009/10 -1.Half 2016/17) were collected from two media based register (® and®). 357 fractures from 290 different players were recorded with an incidences of 0.19/1000 h of exposure (95% 0.14 - 0.24). Most fractures in German elite soccer players involved the lower extremities (35.3%), the head/face (30.3%) and the upper extremities (24.9%). The median off time after a fracture in German elite male professional soccer in 7.5 Season was 51.1 days (range 0-144). The number of fractures per 100 players per season decreased between 2009 and 2016. There was no significant difference in overall fracture incidence when comparing players at different position (p=0.11). Goalkeepers have a significantly (pelite soccer. The incidence of fractures in elite German soccer players decreased between 2009 and 2016. The most fractures occur in the lower extremities and there is no difference in overall fracture risk for players at different playing positions. The information from our study might be of a great importance to medical practitioners, soccer coaches and soccer manager.

  4. The elastic properties of fractured rocks (United States)

    Darcel, C.; Le Goc, R.; Davy, P.


    The consequences of fracturing on rock mass strength still remain an issue for rock engineering practices, including excavation or repository design, support design, slope stability and caving in mines. The difficulty is twice and concerns both the description of the fracturing pattern, and the relationship between fracture characteristics and rock mass mechanical properties. This is generally assessed by empirical knowledge but no complete quantitative and theoretical relations are yet established. To our knowledge, the only theoretical work was to found a relationship between the elastic strength and the percolation parameter (i.e. a normalized sum of the cube of fracture radius) for 3D frictionless fracture networks. The relationship has been demonstrated for Poissonian (randomly distributed) low-density (i.e. where fractures are not almost intersecting) networks, with a narrow range of fracture radius. By means of finite-element models and Green's function methods, we extend the analysis to fracture networks with geologically realistic geometry: i.e. non-Poissonian, relatively high densities, and power-law length distributions. The elastic strength of the fractured rock mass is still found to decrease exponentially with the percolation parameter on average. But large deviations from the mean exist for heavy tailed fracture length distribution, i.e. when the probability of having fractures of the order of the system size is no more negligible. We discuss the way to ameliorate the prediction by taking into account configuration details that are not described by statistical parameters.

  5. Sport-Related Maxillo-Facial Fractures. (United States)

    Ruslin, Muhammad; Boffano, Paolo; ten Brincke, Y J D; Forouzanfar, Tymour; Brand, Henk S


    Sports and exercise are important causes of maxillofacial injuries. Different types of sports might differ in frequency and type of fractures. The aim of the present study was to explore the possible relation between the types of sport practiced and the frequency and nature of the facial bone fractures of patients presenting in an oral and maxillofacial surgery department of a Dutch university center. This study is based on an analysis of patient records containing maxillofacial fractures sustained between January 1, 2000 and April 1, 2014 at the Vrije Universiteit University Medical Center (VUmc) in Amsterdam, The Netherlands. The present study comprised data from 108 patients with 128 maxillofacial fractures. Seventy-nine percent of the patients were male and 21% were female. The patients ranged in age from 10 to 64 years old with a mean age of 30.6 ± 12.0. The highest incidence of sport-related maxillofacial fractures occurred in individuals between the ages of 20 and 29. The most common sport-related fractures were zygoma complex fractures, followed by mandible fractures. Soccer and hockey were the most prominent causes of sport-related maxillofacial trauma in the present study. Coronoid process fractures were only observed in soccer players and not in other sports groups. Mandible angle fractures were relatively more frequent in rugby than in other sports. The results of this study suggest a relation between type of sport and the nature and frequency of the fractures it causes.

  6. Low energy fractures of the acetabulum. (United States)

    Papadakos, N; Pearce, R; Bircher, M D


    Acetabular fractures due to high energy injuries are common and well documented; those secondary to low energy mechanisms are less well described. We undertook a retrospective study of the acetabular fracture referrals to our unit to evaluate the proportion of injuries resulting from a low energy mechanism. A total of 573 acetabular fractures were evaluated from 1 January 2005 to 31 December 2008. The plain radiography and computed tomography of those sustaining a low energy fracture were assessed and the fracture patterns classified. Of the 573 acetabular fractures, 71 (12.4%) were recorded as being a result of a low energy mechanism. The male-to-female ratio was 2.4:1 and the mean patient age was 67.0 years (standard deviation: 19.1 years). There was a significantly higher number of fractures (pfracture studies. Our results demonstrate that low energy fractures make up a considerable proportion of acetabular fractures with a distinctly different fracture pattern distribution. With the continued predicted rise in the incidence of osteoporosis, life expectancy and an aging population, it is likely that this type of fracture will become increasingly more common, posing difficult management decisions and leading to procedures that are technically more challenging.

  7. Mixed-mode fracture of ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.


    The mixed-mode fracture behavior of ceramic materials is of importance for monolithic ceramics in order to predict the onset of fracture under generalized loading conditions and for ceramic composites to describe crack deflection toughening mechanisms. Experimental data on surface flaw mixed-mode fracture in various ceramics indicate that the flaw-plane normal stress at fracture decreases with increasing in-flaw-plane shear stress, although present data exhibit a fairly wide range in details of this sigma - tau relationship. Fracture from large cracks suggests that Mode II has a greater effect on Mode I fracture than Mode III. A comparison of surface flaw and large crack mixed-mode I-II fracture responses indicated that surface flaw behavior is influenced by shear resistance effects.

  8. Evidence-based medicine: Metacarpal fractures. (United States)

    Bloom, Jacob M P; Hammert, Warren C


    After studying this article, the participant should be able to: (1) Determine the need for operative treatment of metacarpal fractures. (2) Describe the position of immobilization for nonoperative treatment of fifth metacarpal fractures. (3) Assess the differences between intramedullary pinning and transverse pinning of displaced metacarpal fractures. (4) Compare the advantages of plating and pinning for treatment of displaced metacarpal fractures. (5) Recognize appropriate timing and treatment of open metacarpal fractures. The body of evidence regarding the treatment of metacarpal fractures continues to grow. Conservative management, closed reduction with percutaneous Kirschner wire fixation, intramedullary fixation, and open reduction and internal fixation with plates and/or screws are all accepted treatment modalities. The goal of this review is to highlight the most recent literature and the best evidence available for the management of metacarpal fractures.

  9. Routine functional assessment for hip fracture patients

    DEFF Research Database (Denmark)

    Pedersen, Tonny J; Lauritsen, Jens M


    Background and purpose - Pre-fracture functional level has been shown to be a consistent predictor of rehabilitation outcomes in older hip fracture patients. We validated 4 overall pre-fracture functional level assessment instruments in patients aged 65 or more, used the prediction of outcome at 4...... months post-fracture, and assessed cutoff values for decision making in treatment and rehabilitation. Patients and methods - 165 consecutive patients with acute primary hip fracture were prospectively included in the study. Pre-fracture Barthel-20, Barthel-100, cumulated ambulation score, and new...... mobility score were scored immediately after admission. Outcome defined as mortality, residential status, and independent walking ability was assessed at 4 months. Results - 3 of the assessment instruments, namely Barthel-20, Barthel-100, and new mobility score, correlated with outcome at 4 months post-fracture...

  10. Effect of Poroelasticity on Hydraulic Fracture Interactions

    DEFF Research Database (Denmark)

    Usui, Tomoya; Salimzadeh, Saeed; Paluszny, Adriana


    This study investigates, by performing finite element-based simulations, the influence of fluid leak-off and poroelasticity on growth of multiple hydraulic fractures that initiate from a single horizontal well. In this research, poroelastic deformation of the matrix is coupled with fluid flow...... in the fractures, and fluid flow in the rock matrix, in three dimensions. Effects of the fluid leakoff and poroelasticity on the propagation of the neighboring fractures are studied by varying the matrix permeability, and the Biot coefficient. Simulation results show that the stress induced by the opening...... of the fractures, and the stress induced by the fluid leak-off, each have the effect of locally altering the magnitudes and orientations of the principal stresses, hence altering the propagation direction of the fractures. The stress induced by the opening of the fractures tends to propagate both of the fractures...

  11. Incidence and epidemiology of tibial shaft fractures

    DEFF Research Database (Denmark)

    Larsen, Peter; Elsøe, Rasmus; Hansen, Sandra Hope


    Introduction: The literature lacks recent population-based epidemiology studies of the incidence, trauma mechanism and fracture classification of tibial shaft fractures. The purpose of this study was to provide up-to-date information on the incidence of tibial shaft fractures in a large...... and complete population and report the distribution of fracture classification, trauma mechanism and patient baseline demographics. Methods: Retrospective reviews of clinical and radiological records. Results: A total of 196 patients were treated for 198 tibial shaft fractures in the years 2009 and 2010....... The mean age at time of fracture was 38.5 (21.2SD) years. The incidence of tibial shaft fracture was 16.9/100,000/year. Males have the highest incidence of 21.5/100,000/year and present with the highest frequency between the age of 10 and 20, whereas women have a frequency of 12.3/100,000/year and have...

  12. The use of thermally expandable microcapsules for increasing the toughness and heal structural adhesives

    Directory of Open Access Journals (Sweden)

    Chiaki Sato


    Full Text Available In this research, the effect of thermally expandable microcapsules (TEMs on mode I fracture toughness of structural adhesives were investigated. The single-edge-notch bending (SENB test was used. Firstly, a standard toughness test was performed on adhesives with microcapsules. Secondly, since TEMs start their expansion at approximately 60ºC, the next specimens were fatigue tested expecting a local heating in the notch leading to the desired expansion before being statically loaded for fracture toughness determination. Thirdly, a manual local heating at 90ºC was applied in the notch before the fracture static test. The experimental results were successfully cross-checked through a numerical analysis using the virtual crack closure technique (VCCT based on linear elastic fracture mechanics (LEFM. The major conclusion is that fracture toughness of the modified adhesives increased as the mass fraction of the TEMs increased.

  13. Ipsilateral humeral neck and shaft fractures

    Directory of Open Access Journals (Sweden)

    Zhu Bin


    Full Text Available Background/Aim. Fractures of the proximal humerus or shaft are common, however, ipsilateral neck and shaft humerus fracture is a rare phenomenon. This combination injury is challenging for orthopaedic surgeons because of its complex treatment options at present. The purpose of this study was to review a series of ipsilateral humeral neck and shaft fractures to study the fracture pattern, complications and treatment outcomes of each treatment options used. Methods. A total of six patients (four female and two male with the average age of 42.8 years (range: 36–49 years was collected and reviewed retrospectively. Two of them were treated with double plates and four with antegrade intramedullary nail. According to the Neer’s classification, all proximal fractures were two-part surgical neck fractures. All humeral shaft fractures were located at the middle of one third. Five fractures were simple transverse (A3, one fragmented wedge fracture (B3. One patient had associated radial nerve palsy. Results. All surgical neck fractures except one united uneventfully in the average time span of 8.7 weeks. Four humeral shaft fractures healed in near anatomic alignment. The remaining two patients had the nonunion with no radiological signs of fracture healing. The average University of California, Los Angeles End-Results (UCLA score was 23.1. On the contrary, the average American Shoulder and Elbow Surgeon's (ASES score was 73.3. The patients treated with antegrade intramedullary nails presented 70.5 points. The ASES scores were 79 in the double plates group. Conclusions. Ipsilateral humeral shaft and neck fracture is extremely rare. Both antegrade intramedullar nailing and double plates result in healing of fractures. However the risk of complication is lower in the double plating group.

  14. Characteristics of Alcohol-Related Facial Fractures. (United States)

    Lee, Kai H; Qiu, Michael


    Excessive indulgence in alcohol is a key causative factor in facial fractures especially in settings of interpersonal violence (IPV) and motor vehicle accidents. This study aims to explore characteristics of alcohol-involved facial fractures in the state of Victoria, Australia, over a 10-year period. This retrospective study analyzed data from the Victorian Admitted Episodes Dataset between 2004 and 2014; the Victorian Admitted Episodes Dataset is a standardized database reported by all Victorian hospitals for every admission. Admission details included patient age group and gender, fracture site (or sites), injury cause, and surgical management. During the study period, 4,293 patients were treated for alcohol-related facial fractures, 27% of whom were in the 20- to 29-year-old age group. The male-to-female ratio was 7:1. There was a rising trend over most of the study period. Of the patients, 36% had multiple facial bone fractures, followed by nasal and midface fractures (22% and 6%, respectively). IPV was the most frequent cause (38%), followed by falls and transport-related injuries (30% and 18%, respectively). Surgery was required in 16% of patients, and 62% were inpatients for 1 to 3 days. Concomitant fractures were frequently reported; 20% of patients had fractures of another site, 12% had skull fractures, and 4% had cervical spine fractures. There were statistically significant relationships between age group and gender, between gender and fracture site, and between fracture site and need for surgery (P < .05). This study reports a high incidence of alcohol-involved facial fractures in young men with IPV being a predominant cause. Such injuries often involve multiple facial bone fractures and severe concomitant trauma necessitating brief hospitalizations, but a high proportion of patients were treated nonsurgically. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  15. Percutaneous plating of distal tibial fractures. (United States)

    Khoury, Amal; Liebergall, Meir; London, Eli; Mosheiff, Rami


    This article presents our experience with 24 patients who had distal tibial fractures and were treated by percutaneous plate fixation. Distribution of the fractures according to the AO/OTA classification was as follows: five patients suffered from a 43 A type fracture, six from a 43 B type fracture, and 13 from a 43 C type fractures. Four of the fractures were open. Exclusion criteria included 43 C3 fractures and Gustilo III open fractures. All fractures showed radiographic signs of union enough to enable full weightbearing within an average time of 12.3 weeks. All patients showed a good range of motion (average dorsiflexion 12 degrees and average plantiflexion 18 degrees). Two fractures united with mal-union: one with an 8 degrees valgus deformity and another with a 7 degrees varus deformity. Both cases, which had a metaphyseal component, were treated by means of a "soft" (flexible and manually adjustable) AO 3.5 mm reconstruction plate. Except for one case of superficial infection, no infections were detected in any of the patients. The biological percutaneous plate fixation of distal tibial fractures with no extensive intra-articular involvement is a good soft tissue preserving technique. It provides a rigid and anatomical fixation in most cases. We conclude that type B fractures with one intact column can be fixed with either "soft" or "rigid" plates, and type A and C fractures with a metaphyseal component should be fixed with "rigid" plates (AO 4.5 mm Dynamic Compression Plate). In these fractures the reduction should be performed cautiously due to the tendency of sagittal plane mal-reduction.

  16. Hydraulic fracturing model based on the discrete fracture model and the generalized J integral (United States)

    Liu, Z. Q.; Liu, Z. F.; Wang, X. H.; Zeng, B.


    The hydraulic fracturing technique is an effective stimulation for low permeability reservoirs. In fracturing models, one key point is to accurately calculate the flux across the fracture surface and the stress intensity factor. To achieve high precision, the discrete fracture model is recommended to calculate the flux. Using the generalized J integral, the present work obtains an accurate simulation of the stress intensity factor. Based on the above factors, an alternative hydraulic fracturing model is presented. Examples are included to demonstrate the reliability of the proposed model and its ability to model the fracture propagation. Subsequently, the model is used to describe the relationship between the geometry of the fracture and the fracturing equipment parameters. The numerical results indicate that the working pressure and the pump power will significantly influence the fracturing process.

  17. Laboratory experimental investigation of heat transport in fractured media (United States)

    Cherubini, Claudia; Pastore, Nicola; Giasi, Concetta I.; Allegretti, Nicoletta Maria


    thermal breakthrough curves, the Explicit Network Model (ENM) has been used, which is based on an adaptation of Tang's solution for the transport of the solutes in a semi-infinite single fracture embedded in a porous matrix. Parameter estimation, time moment analysis, tailing character and other dimensionless parameters have permitted a better understanding of the dynamics of heat transport and the efficiency of heat exchange between the fractures and the matrix. The results have been compared with the previous experimental studies on solute transport.

  18. Hydraulic fracturing: insights from field, lab, and numerical studies (United States)

    Walsh, S. D.; Johnson, S.; Fu, P.; Settgast, R. R.


    Hydraulic fracturing has become an increasingly important technique in stimulating reservoirs for gas, oil, and geothermal energy production. In use commercially since the 1950's, the technique has been widely lauded, when combined with other techniques, for enabling the development of shale gas resources in the United States, providing a valuable and extensive source of domestic energy. However, the technique has also drawn a degree of notoriety from high-profile incidents involving contamination of drinking water associated with gas extraction operations in the Marcellus shale region. This work highlights some of the insights on the behavior of subsurface hydraulic fracturing operations that have been derived from field and laboratory observations as well as from numerical simulations. The sensitivity of fracture extent and orientation to parameters such as matrix material heterogeneity, presence and distribution of discontinuities, and stress orientation is of particular interest, and we discuss this in the context of knowledge derived from both observation and simulation. The limitations of these studies will also be addressed in terms of resolution, uncertainty, and assumptions as well as the balance of fidelity to cost, both in computation time (for numerical studies) and equipment / operation cost (for observational studies). We also identify a number of current knowledge gaps and propose alternatives for addressing those gaps. We especially focus on the role of numerical studies for elucidating key concepts and system sensitivities. The problem is inherently multi-scale in both space and time as well as highly coupled hydromechanically, and, in several applications, thermally as well. We will summarize the developments to date in analyzing these systems and present an approach for advancing the capabilities of our models in the short- to long-term and how these advances can help provide solutions to reduce risk and improve efficiency of hydraulic fracturing

  19. Synthesis report on thermally driven coupled processes

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, E.L.


    The main purpose of this report is to document observations and data on thermally coupled processes for conditions that are expected to occur within and around a repository at Yucca Mountain. Some attempt is made to summarize values of properties (e.g., thermal properties, hydrologic properties) that can be measured in the laboratory on intact samples of the rock matrix. Variation of these properties with temperature, or with conditions likely to be encountered at elevated temperature in the host rock, is of particular interest. However, the main emphasis of this report is on direct observation of thermally coupled processes at various scales. Direct phenomenological observations are vitally important in developing and testing conceptual models. If the mathematical implementation of a conceptual model predicts a consequence that is not observed, either (1) the parameters or the boundary conditions used in the calculation are incorrect or (2) the conceptual basis of the model does not fit the experiment; in either case, the model must be revised. For example, the effective continuum model that has been used in thermohydrology studies combines matrix and fracture flow in a way that is equivalent to an assumption that water is imbibed instantaneously from fractures into adjacent, partially saturated matrix. Based on this approximation, the continuum-flow response that is analogous to fracture flow will not occur until the effective continuum is almost completely saturated. This approximation is not entirely consistent with some of the experimental data presented in this report. This report documents laboratory work and field studies undertaken in FY96 and FY97 to investigate thermally coupled processes such as heat pipes and fracture-matrix coupling. In addition, relevant activities from past years, and work undertaken outside the Yucca Mountain project are summarized and discussed. Natural and artificial analogs are also discussed to provide a convenient source of

  20. Evaluation of associated carpal bone fractures in distal radial fractures. (United States)

    Heo, Youn Moo; Kim, Sang Bum; Yi, Jin Woong; Lee, Jung Bum; Park, Cheol Yong; Yoon, Jeong Yong; Kim, Doo Hyun


    The purpose of this study was to investigate the frequency and distribution of associated carpal bone fractures (CBFs) in distal radial fractures (DRFs). Three hundred and thirteen patients who underwent surgical treatment for DRFs between March 2007 and January 2010 were reviewed retrospectively. In this study, 223 patients who had preoperative computed tomography (CT) were included. We investigated the frequency and distribution of associated CBFs on CT scans. The relationship between the frequency of associated CBFs and patient factors such as age, gender, body mass index, and the mechanism of injury was assessed. CBFs were complicated in 46 of 223 DRFs (20.9%). The distribution of CBFs was 23 cases in the triquetrum, 16 in the lunate, 12 in the scaphoid, five in the hamate, and four in the pisiform. Among the 46 cases, a fracture of one carpal bone occurred in 36 cases, two in seven cases, three in two cases, and four in one case. In 10 of the 46 cases, associated CBFs occurred in more than two carpal bones. No significant differences were observed for age, sex, body mass index, or the mechanism of injury between patients with DRFs and CBFs and those without CBFs. Because CBFs that mainly occur in the proximal carpal row are complicated in DRFs at a relatively high frequency, assessment of carpal bones using CT scans is beneficial.

  1. Control of the permeability of fractures in geothermal rocks (United States)

    Faoro, Igor

    This thesis comprises three journal articles that will be submitted for publication (Journal of Geophysical Research-Solid Earth). Their respective titles are: "Undrained through Drained Evolution of Permeability in Dual Permeability Media" by Igor Faoro, Derek Elsworth and Chris Marone, "Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution" by Igor Faoro, Derek Elsworth Chris Marone; "Linking permeability and mechanical damage for basalt from Mt. Etna volcano (Italy)" by Igor Faoro, Sergio Vinciguerra, Chris Marone and Derek Elsworth. Undrained through Drained Evolution of Permeability in Dual Permeability Media: temporary permeability changes of fractured aquifers subject to earthquakes have been observed and recorded worldwide, but their comprehension still remains a complex issue. In this study we report on flow-through fracture experiments on cracked westerly cores that reproduce, at laboratory scale, those (steps like) permeability changes that have been recorded when earthquakes occur. In particular our experiments show that under specific test boundary conditions, rapid increments of pore pressure induce transient variations of flow rate of the fracture whose peak magnitudes decrease as the variations of the effective stresses increase. We identify that the observed hydraulic behavior of the fracture is due to two principal mechanisms of origin; respectively mechanical (shortening of core) and poro-elastic (radial diffusion of the pore fluid into the matrix of the sample) whose interaction cause respectively an instantaneous opening and then a progressive closure of the fracture. Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution: we report the results of radial flow-through experiments conducted on heated samples of Westerly granite. These experiments are performed to examine the influence of thermally and mechanically activated

  2. Quality of fracture risk assessment in post-fracture care in Ontario, Canada. (United States)

    Allin, S; Munce, S; Schott, A-M; Hawker, G; Murphy, K; Jaglal, S B


    As fracture risk assessment is a basis for treatment decisions, accurate risk assessments on bone mineral density (BMD) reports are important. Over 50 % of sampled BMD reports for Ontarians with fracture histories underestimated fracture risk by a single category. Risk assessments in Ontario may not accurately inform treatment recommendations. The shifting emphasis on fracture risk assessment as a basis for treatment recommendations highlights the importance of ensuring that accurate fracture risk assessments are present on reading specialists' BMD reports. This study seeks to determine the accuracy of fracture risk assessments on a sample of BMD reports from 2008 for individuals with a history of fracture and produced by a broad cross section of Ontario's imaging laboratories. Forty-eight BMD reports for individuals with documented history of fragility fracture were collected as part of a cluster randomized trial. To compute fracture risk, risk factors, and BMD T-scores from reports were abstracted using a standardized template and compared to the assessments on the reports. Cohen's kappa was used to score agreement between the research team and the reading specialists. The weighted kappa was 0.21, indicating agreement to be at the margin of "poor to fair." More than 50 % of the time, reported fracture risks did not reflect fracture history and were therefore underestimated by a single category. Over 30 % of the reports containing a "low" fracture risk assessment were assessed as "moderate" fracture risk by the research team, given fracture history. Over 20 % of the reports with a "moderate" fracture risk were assessed as "high" by the research team, given fracture history. This study highlights the high prevalence of fracture risk assessments that are underestimated. This has implications in terms of fracture risk categorization that can negatively affect subsequent follow-up care and treatment recommendations.

  3. Ultrahigh Thermal Conductive yet Superflexible Graphene Films. (United States)

    Peng, Li; Xu, Zhen; Liu, Zheng; Guo, Yan; Li, Peng; Gao, Chao


    Electrical devices generate heat at work. The heat should be transferred away immediately by a thermal manager to keep proper functions, especially for high-frequency apparatuses. Besides high thermal conductivity (K), the thermal manager material requires good foldability for the next generation flexible electronics. Unfortunately, metals have satisfactory ductility but inferior K (≤429 W m(-1) K(-1) ), and highly thermal-conductive nonmetallic materials are generally brittle. Therefore, fabricating a foldable macroscopic material with a prominent K is still under challenge. This study solves the problem by folding atomic thin graphene into microfolds. The debris-free giant graphene sheets endow graphene film (GF) with a high K of 1940 ± 113 W m(-1) K(-1) . Simultaneously, the microfolds render GF superflexible with a high fracture elongation up to 16%, enabling it more than 6000 cycles of ultimate folding. The large-area multifunctional GFs can be easily integrated into high-power flexible devices for highly efficient thermal management. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Thermal Ignition (United States)

    Boettcher, Philipp Andreas

    Accidental ignition of flammable gases is a critical safety concern in many industrial applications. Particularly in the aviation industry, the main areas of concern on an aircraft are the fuel tank and adjoining regions, where spilled fuel has a high likelihood of creating a flammable mixture. To this end, a fundamental understanding of the ignition phenomenon is necessary in order to develop more accurate test methods and standards as a means of designing safer air vehicles. The focus of this work is thermal ignition, particularly auto-ignition with emphasis on the effect of heating rate, hot surface ignition and flame propagation, and puffing flames. Combustion of hydrocarbon fuels is traditionally separated into slow reaction, cool flame, and ignition regimes based on pressure and temperature. Standard tests, such as the ASTM E659, are used to determine the lowest temperature required to ignite a specific fuel mixed with air at atmospheric pressure. It is expected that the initial pressure and the rate at which the mixture is heated also influences the limiting temperature and the type of combustion. This study investigates the effect of heating rate, between 4 and 15 K/min, and initial pressure, in the range of 25 to 100 kPa, on ignition of n-hexane air mixtures. Mixtures with equivalence ratio ranging from 0.6 to 1.2 were investigated. The problem is also modeled computationally using an extension of Semenov's classical auto-ignition theory with a detailed chemical mechanism. Experiments and simulations both show that in the same reactor either a slow reaction or an ignition event can take place depending on the heating rate. Analysis of the detailed chemistry demonstrates that a mixture which approaches the ignition region slowly undergoes a significant modification of its composition. This change in composition induces a progressive shift of the explosion limit until the mixture is no longer flammable. A mixture that approaches the ignition region

  5. Thermal-induced residual stresses affect the fractographic patterns of zirconia-veneer dental prostheses. (United States)

    Belli, Renan; Petschelt, Anselm; Lohbauer, Ulrich


    Veneer fractures in dental zirconia-veneer prostheses are more frequent clinically than in conventional metal-ceramic systems. This is thought to be due to the increased residual stresses generated within the veneer during fabrication when zirconia is the infrastructure material. This investigation aimed to analyze the fractographic features of fractured zirconia-veneer dental crowns submitted to a load-to-failure test and to a more clinically relevant in vitro chewing simulation fatigue test. As-sintered and sandblasted zirconia copings were veneered with glass-ceramic with different coefficients of thermal expansion and cooled following two cooling rates, creating, this way, different levels of stresses within the veneer. Crowns with different thermal mismatch combinations and different cooling rates were hypothesized to present particular fracture patterns. A careful examination of >1000 scanning electron microscopy images of the fracture surfaces was conducted in search of characteristic fractographic markings of fracture mechanisms connected to the stress state of the veneer. Distinctive structural features could be observed between groups veneered with the two different glass-ceramics and between fractured crowns under static and cyclic loading. The presence/absence of residual stresses zones within the veneer have shown to play the major role in the fracture pattern of zirconia-veneer dental prostheses. For the fatigue crowns, the zirconia core was never exposed, either for sandblasted and as-sintered groups. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Occult fracture of the calcaneus - another toddler's fracture

    Energy Technology Data Exchange (ETDEWEB)

    Starshak, R.J.; Simons, G.W.; Sty, J.R.


    Fractures of the calcaneus have been considered rare among children. We feel this may be erroneous since in the last 12 months we have seen 10 such fractures among children, 19 and 41 months of age, who presented with acute limping. The fractures were detected with bone imaging which was performed when initial radiographs were noncontributory. Subsequent radiographs of the calcaneus were positive for fracture in 4 to 10 while follow up radiographs confirmed healing fractures in the two children so evaluated. The sensitivity of bone imaging for the detection of occult fractures in toddlers is emphasized.

  7. Functional treatment for fractures to the base of the 5th metatarsal - influence of fracture location and fracture characteristics. (United States)

    Baumbach, Sebastian Felix; Prall, Wolf Christian; Kramer, Michael; Braunstein, Mareen; Böcker, Wolfgang; Polzer, Hans


    Fractures to the base of the fifth metatarsal are common, but their treatment remains controversial. Especially for Lawrence and Botte (L&B) type II fractures, there is conflicting evidence and consequently no consensus. Further, many authors consider displacement, articular involvement, and number of fragments an indication for surgery, although evidence is missing. The aim of this study was to evaluate the outcome of functional treatment for all L&B type I and II fractures. Of special interest were the influence of (1) the fracture location (L&B type I vs. II) and (2) the fracture characteristics (displacement, intra-articular involvement, communition) on the subjective outcome. Retrospective registry study with a prospective follow-up. Patients with an acute, isolated, epi-metaphyseal fracture to the fifth metatarsal bone (L&B type I and II) treated by full weightbearing with a minimum follow-up of 6 months were included. Fracture location (L&B type I and II) and characteristics (displacement 2 mm, intra-articular involvement, and number of fragments) were assessed. Outcome parameters were return to work, return to sports, VAS-FA, and SF-12. The influence of the fracture (1) location and (2) -characteristics on these parameters was tested. Thirty-nine patients (40 ± 15 years, 56% female) were enrolled with a mean follow-up of 22 ± 10 months. L&B type I fractures occurred in 59%, type II in 41%. Thirty-one percent of all fractures were dislocated, 74% intra-articular, and 41% multi-fragmentary. Patients returned to work after 17 ± 12 days, to sports after 53 ± 22 days. The VAS-FA score at the final follow-up was 96 ± 4, SF-12 PCS score 57 ± 5 and MCS score 51 ± 8. No complications were reported, no patient required surgery. None of the assessed outcome parameters differed significantly between (1) the different fracture locations (L&B type I vs. II) or (2) the different fracture characteristics (displacement, intra

  8. Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology

    Directory of Open Access Journals (Sweden)

    Lihui Lang


    Full Text Available In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM. The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

  9. Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology (United States)

    Lang, Lihui; Zhang, Quanda; Sun, Zhiying; Wang, Yao


    In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM). The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

  10. The healing of fractured bones

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Central Electricity Generating Board, Cheltenham (United Kingdom)


    A method utilising neutron beams of width 1 mm, used on D1B (2.4 A) and D20 (1.3 A) to study the healing of fractured bones is presented. It is found that the callus bone uniting the fractured tibia of a sheep, whose healing had been encouraged by daily mechanical vibration over a period of three months, showed no trace of the large preferential vertical orientation of the apatite crystals which is characteristic of the normal bone. Nevertheless the bone had regained about 60% of its mechanical strength and the callus bone, although not oriented, was well crystallized. It is considered that the new monochromator for D20, expected to give increased intensity at 2.5 A, will be of considerable advantage. (author). 2 refs.

  11. Rehabilitation for ankle fractures in adults. (United States)

    Lin, Chung-Wei Christine; Donkers, Nicole A J; Refshauge, Kathryn M; Beckenkamp, Paula R; Khera, Kriti; Moseley, Anne M


    Rehabilitation after ankle fracture can begin soon after the fracture has been treated, either surgically or non-surgically, by the use of different types of immobilisation that allow early commencement of weight-bearing or exercise. Alternatively, rehabilitation, including the use of physical or manual therapies, may start following the period of immobilisation. This is an update of a Cochrane review first published in 2008. To assess the effects of rehabilitation interventions following conservative or surgical treatment of ankle fractures in adults. We searched the Specialised Registers of the Cochrane Bone, Joint and Muscle Trauma Group and the Cochrane Rehabilitation and Related Therapies Field, CENTRAL via The Cochrane Library (2011 Issue 7), MEDLINE via PubMed, EMBASE, CINAHL, PEDro, AMED, SPORTDiscus and clinical trials registers up to July 2011. In addition, we searched reference lists of included studies and relevant systematic reviews. Randomised and quasi-randomised controlled trials with adults undergoing any interventions for rehabilitation after ankle fracture were considered. The primary outcome was activity limitation. Secondary outcomes included quality of life, patient satisfaction, impairments and adverse events. Two review authors independently screened search results, assessed risk of bias and extracted data. Risk ratios and 95% confidence intervals (95% CIs) were calculated for dichotomous variables, and mean differences or standardised mean differences and 95% CIs were calculated for continuous variables. End of treatment and end of follow-up data were presented separately. For end of follow-up data, short term follow-up was defined as up to three months after randomisation, and long-term follow-up as greater than six months after randomisation. Meta-analysis was performed where appropriate. Thirty-eight studies with a total of 1896 participants were included. Only one study was judged at low risk of bias. Eight studies were judged at high

  12. Factors influencing the fracture of dental implants. (United States)

    Chrcanovic, Bruno Ramos; Kisch, Jenö; Albrektsson, Tomas; Wennerberg, Ann


    Implant fractures are rare but offer a challenging clinical situation. To determine the prevalence of implant fracture and the possible risk factors predisposing an implant to a higher fracture risk. This retrospective study is based on 2670 patients consecutively treated with implant-supported prostheses. Anatomical-, patient-, and implant-related factors were collected. Descriptive statistics and survival analyses were performed. Generalized estimating equations (GEE) evaluated the effect of explanatory variables on implant fracture. Forty-four implants (out of 10 099; 0.44%) fractured. The mean ± standard deviation time for fracture to occur was 95.1 ± 58.5 months (min-max, 3.8-294.7). Half of the occurrences of fracture happened between 2 and 8 years after implantation. Five factors had a statistically significant influence on the fracture of implants (increase/decrease in fracture probability): use of higher grades of titanium (decrease 72.9%), bruxism (increase 1819.5%), direct adjacency to cantilever (increase 247.6%), every 1 mm increase in implant length (increase 22.3%), every 1 mm increase in implant diameter (decrease 96.9%). It is suggested that 5 factors could influence the incidence of implant fractures: grade of titanium, implant diameter and length, cantilever, bruxism. © 2017 Wiley Periodicals, Inc.

  13. Antegrade interlocking nailing of humeral shaft fractures. (United States)

    Petsatodes, George; Karataglis, Dimitrios; Papadopoulos, Pericles; Christoforides, John; Gigis, John; Pournaras, John


    The results of 39 humeral shaft fractures (37 patients) treated with antegrade locked nailing using a Russell-Taylor nail were reviewed. There were 30 acute fractures, 6 fractures malaligned in a hanging cast or brace, and 3 pathological fractures. Patient age ranged from 26 to 80 years (average, 59.7 years) and average follow-up was 25.7 months (range, 6-48 months). Fracture union was achieved in 92.3% of our cases, while shoulder function was excellent or good in 87.2% of cases. Antegrade locked nailing offers a dependable solution for the treatment of humeral shaft fractures, especially in polytrauma patients and cases of segmental or pathological fractures. Far less satisfactory results were obtained in comminuted fractures of the proximal third in the humerus, especially in osteoporotic patients, and we therefore advocate caution with the use of intramedullary nailing in this type of fracture. Certain technical aspects such as avoiding nailing the fracture in distraction, properly countersinking the tip of the nail, and achieving adequate fixation stability have been found to be of paramount importance to reduce the incidence of delayed union/non-union rate and to obtain better functional results from the shoulder joint. The Japanese Orthopaedic Association

  14. Natural fracture characterization using passive seismic illumination

    Energy Technology Data Exchange (ETDEWEB)

    Nihei, K.T.


    The presence of natural fractures in reservoir rock can significantly enhance gas production, especially in tight gas formations. Any general knowledge of the existence, location, orientation, spatial density, and connectivity of natural fractures, as well as general reservoir structure, that can be obtained prior to active seismic acquisition and drilling can be exploited to identify key areas for subsequent higher resolution active seismic imaging. Current practices for estimating fracture properties before the acquisition of surface seismic data are usually based on the assumed geology and tectonics of the region, and empirical or fracture mechanics-based relationships between stratigraphic curvature and fracturing. The objective of this research is to investigate the potential of multicomponent surface sensor arrays, and passive seismic sources in the form of local earthquakes to identify and characterize potential fractured gas reservoirs located near seismically active regions. To assess the feasibility of passive seismic fracture detection and characterization, we have developed numerical codes for modeling elastic wave propagation in reservoir structures containing multiple, finite-length fractures. This article describes our efforts to determine the conditions for favorable excitation of fracture converted waves, and to develop an imaging method that can be used to locate and characterize fractures using multicomponent, passive seismic data recorded on a surface array.

  15. Rigid internal fixation of infected mandibular fractures. (United States)

    Mehra, Pushkar; Van Heukelom, Emily; Cottrell, David A


    To evaluate the treatment outcomes of rigid internal fixation for the management of infected mandible fractures. A retrospective chart review of infected mandible fractures managed by a single oral and maxillofacial surgeon at a level I trauma center during a 7-year period was accomplished by independent examiners. All patients were treated with incision and drainage, culture and sensitivity testing, extraction of nonsalvageable teeth, placement of maxillomandibular fixation when possible, fracture reduction with bone debridement and decortication, rigid internal fixation of the mandible by an extraoral approach, and antibiotic therapy. The medical and social history was contributory in most patients. The analysis was stratified by the differentiation of the fractures into 2 groups: those with soft tissue infections in the fracture region versus those with hard tissue-infected fractures (biopsy-proven osteomyelitis). A total of 44 patients were included in this study, with an average follow-up of 18.2 months from the date of surgery (range 3 to 48). The treatment protocol was successful in all 18 patients (100%) with soft tissue infected mandibular fractures and 24 (92%) of 26 patients with hard tissue-infected fractures. A protocol consisting of concomitant incision and drainage, mandibular debridement, fracture reduction, and stabilization with rigid internal fixation can be effectively used for single-stage management of infected mandible fractures.

  16. Intertrochanteric fracture under an arthrodesed hip. (United States)

    Darwish, Fayeq M; Haddad, Walid


    Female, 30. Intertrochanteric fracture under an arthrodesed hip. Developmental dysplasia of the hip. Pain • inability to walk. Open reduction and internal fixation. Orthopedics and traumatology. Rare disease, Unusual setting of medical care. An intertrochanteric fracture among elderly people is common, but it is rare to see such a fracture under a longstanding hip arthrodesis. Its surgical management represents a real challenge to orthopedic surgeons. A 30-year-old female teacher with long-standing hip arthrodesis was involved in a traffic accident. Clinical and radiological examination revealed the presence of a displaced intertrochanteric fracture under an arthrodesed hip and high neck shaft angle. Before embarking on surgery, we have to consider many factors such as patient personality (a young active and ambitious woman) and the mature of the fracture (a displaced fracture, coxa valga, and atrophied muscles). After a deep discussion and evaluation of the available devices, we selected a heavy duty locked plate and cannulated screws to fix the fracture. Because of the rarity of intertrochanteric fracture under an arthrodesis hip, the proper surgical treatment is controversial. Nevertheless, we were fortunate in successfully treating this unusual fracture using a locked plate and cannulated screws, which are implants that can be useful in treatment of such fractures.

  17. Practical Applications of Fracture Mechanics (United States)


    mounted in a universal teating free• and untaxial loads were applied at the bottom of the penal through a whiffletree system by six hydraulic jacks ...Structure". Published in "Fracture Prevention and Control", American Society for Metas, 1974. 6. C01101WrARY This example is a goodi illustration of the...remaining 13 at another. The lug was an undercarriage operating Jack attachment point, loaded once per Jack operation corresponding to constant

  18. [Kyphoplasty in osteoporotic spinal fractures]. (United States)

    Prokop, A; Löhlein, F; Chmilniecki, M; Volbracht, J; Manner, M


    Kyphoplasty has been the standard procedure for osteoporotic fractures for more than 5 years but the material costs are still very high. The aim of this study was to clarify whether pain reduction could be achieved without increasing the rate of new fractures and also in what areas costs could possibly be reduced. From 15.01.2007 until 15.01.2008, a total of 100 patients with 126 recent osteoporotic spinal fractures were treated by kyphoplasty with an average operation time of 38 min and follow-up times up to 12 months. During this follow-up period 15 lateral and 2 dorsal cement leakages remained asymptomatic and 1 dorsal leakage caused an incomplete paraparesis, which was finally cured completely. All patients were very content and pain measured on the visual analogous scale could be lowered from 8.0 before the operation to 2.7 points after the operation. With material costs of 3,056 Euro, there were additional operation costs of 247 Euro per case. The average effective weight was 2.84. On average 7,810 Euro returns could be achieved, deducting material and operation costs left 4,507 Euro per case. More than 40% of gains were reinvested in operation and material costs. Within 12 months 6 new fractures occurred despite medicinal prophylactic treatment which could also be successfully treated by kyphoplasty. The average visual analogous scale after 12 months was 2.1 points.Kyphoplasty still causes financial deficits due to high material costs, however, patients benefit from a reduction of pain.

  19. Measuring Fracture Times Of Ceramics (United States)

    Shlichta, Paul J.; Bister, Leo; Bickler, Donald G.


    Electrical measurements complement or replace fast cinematography. Electronic system measures microsecond time intervals between impacts of projectiles on ceramic tiles and fracture tiles. Used in research on ceramics and ceramic-based composite materials such as armor. Hardness and low density of ceramics enable them to disintegrate projectiles more efficiently than metals. Projectile approaches ceramic tile specimen. Penetrating foil squares of triggering device activate display and recording instruments. As ceramic and resistive film break oscilloscope plots increase in electrical resistance of film.

  20. Our Results in Penile Fractures

    Directory of Open Access Journals (Sweden)

    Tufan Süelözgen


    Full Text Available Introduction Penile fracture is a urological emergency caused by direct trauma to an erected penis, tearing the tunica albuginea in the corpus cavernosum. The preferred treatment method is draining the hematoma and surgical repair of tunica albuginea tear as soon as possible following diagnosis. Materials and Methods Forty-nine patients who were diagnosed with penile fracture between January 2009 and December 2014 were reviewed. Physical examination was performed to see the extent of penile hematoma, the side of the penile curvature and the presence of blood in the external meatus. Two patients who were diagnosed with urethrorrhagia underwent retrograde urethrogram for urethral injury. In all patients, penile skin was peeled using a circular subcoronal degloving incision and tunica tear was repaired using absorbable suture materials. The patients were then followed for painful erections, penile deformities and erection angles. Results The average age of the 49 patients, who were included in the study, was 36.5 years (21-65. In their etiological questioning, most patients reported the fracture occurring during sexual intercourse. Retrograde urethrography was indicated in 2 patients with blood in the external meatus and were diagnosed with urethral injury. The patients were taken to emergency surgery. Tunica defects varied between 1 and 2 cm. Incomplete urethral injuries were primarily repaired around 18 French Foley catheter. None of the patients reported penile deformity or painful erections. Their erection angles were found to be within the normal range. Conclusion Even though it is a relatively rare condition, penile fractures are so important that might cause serious complications when not treated surgically. A thorough anamnesis and physical examination suffice for diagnosis.