WorldWideScience

Sample records for incidental dislocation boundaries

  1. Prediction of dislocation boundary characteristics

    DEFF Research Database (Denmark)

    Winther, Grethe

    orientation of the grain [1]. For selected boundaries it has been experimentally verified that the boundaries consist of fairly regular networks of dislocations, which come from the active slip systems [2]. The networks have been analyzed within the framework of Low-Energy-Dislocation-Structures (LEDS......, such as the dislocation content and misorientation. The prediction is based on the expected active slip systems and assumptions of mutual stress screening. In general, networks of dislocations with three linearly independent Burgers vectors fulfilling the criterion of mutual stress screening may form on any plane...

  2. Slip systems, lattice rotations and dislocation boundaries

    DEFF Research Database (Denmark)

    Winther, Grethe

    2008-01-01

    of dislocation structure formed, in particular the crystallographic alignment of dislocation boundaries, and the slip pattern are demonstrated. These relations are applied to polycrystals deformed in tension and rolling, producing good agreement with experiment for rolling but less good agreement for tension...

  3. Interactions between Dislocations and Grain Boundaries

    NARCIS (Netherlands)

    Soer, Wouter Anthon

    2006-01-01

    Dislocations (line defects) and grain boundaries (planar defects) are two types of lattice defects that are crucial to the deformation behavior of metals. Permanent deformation of a crystalline material is microscopically associated with the nucleation and propagation of dislocations, and extensive

  4. Dislocation Nucleation on Grain Boundaries: Low Angle Twist and Asymmetric Tilt Boundaries

    Directory of Open Access Journals (Sweden)

    Erman Guleryuz

    2016-07-01

    Full Text Available We investigate the mechanisms of incipient plasticity at low angle twist and asymmetric tilt boundaries in fcc metals. To observe plasticity of grain boundaries independently of the bulk plasticity, we simulate nanoindentation of bicrystals. On the low angle twist boundaries, the intrinsic grain boundary (GB dislocation network deforms under load until a dislocation segment compatible with glide on a lattice slip plane is created. The half loops are then emitted into the bulk of the crystal. Asymmetric twist boundaries considered here did not produce bulk dislocations under load. Instead, the boundary with a low excess volume nucleated a mobile GB dislocation and additional GB defects. The GB sliding proceeded by motion of the mobile GB dislocation. The boundary with a high excess volume sheared elastically, while bulk-nucleated dislocations produced plastic relaxation.

  5. Deformation induced dislocation boundaries: Alignment and effect on mechanical properties

    DEFF Research Database (Denmark)

    Winther, G.; Juul Jensen, D.

    1997-01-01

    The dislocation boundaries formed during cold-rolling of FCC metals have been reported to have a preferred macroscopic direction with respect to the sample axes. However, boundaries have also been reported to form on crystallographic slip planes. The directions of the boundaries formed...

  6. Transformation of slip dislocation in ä3 grain boundary

    Czech Academy of Sciences Publication Activity Database

    Gemperlová, Juliana; Jacques, A.; Gemperle, Antonín; Zárubová, Niva

    2002-01-01

    Roč. 10, - (2002), s. 51-57 ISSN 0927-7056 R&D Projects: GA ČR GA202/98/1281; GA ČR GA202/01/0670 Institutional research plan: CEZ:AV0Z1010914 Keywords : in situ TEM * slip dislocations * grain boundary * grain boundary dislocations * plasticity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.767, year: 2002

  7. The evolution of disorientations for several types of boundaries

    DEFF Research Database (Denmark)

    Pantleon, W.

    2001-01-01

    During plastic deformation dislocation boundaries appear separating regions of different orientation. A model for the occurrence of disorientations across these boundaries is proposed and discussed with emphasis on several types of boundaries. For incidental dislocation boundaries a statistical...

  8. On the Derivation of Boundary Conditions for Continuum Dislocation Dynamics

    Directory of Open Access Journals (Sweden)

    Thomas Hochrainer

    2017-07-01

    Full Text Available Continuum dislocation dynamics (CDD is a single crystal strain gradient plasticity theory based exclusively on the evolution of the dislocation state. Recently, we derived a constitutive theory for the average dislocation velocity in CDD in a phase field-type description for an infinite domain. In the current work, so-called rational thermodynamics is employed to obtain thermodynamically consistent boundary conditions for the dislocation density variables of CDD. We find that rational thermodynamics reproduces the bulk constitutive equations as obtained from irreversible thermodynamics. The boundary conditions we find display strong parallels to the microscopic traction conditions derived by Gurtin and Needleman (M.E. Gurtin and A. Needleman, J. Mech. Phys. Solids 53 (2005 1–31 for strain gradient theories based on the Kröner–Nye tensor.

  9. Slip patterns and preferred dislocation boundary planes

    DEFF Research Database (Denmark)

    Winther, G.

    2003-01-01

    and polycrystals of fcc metals in three deformation modes (rolling, tension and torsion). In the macroscopic system, boundaries lie close to the macroscopically most stressed planes. In the crystallographic system, the boundary plane depends on the grain/crystal orientation. The boundary planes in both co...

  10. Low-Energy Dislocation Structure (LEDS) character of dislocation boundaries aligned with slip planes in rolled aluminium

    DEFF Research Database (Denmark)

    Winther, Grethe; Hong, Chuanshi; Huang, Xiaoxu

    2015-01-01

    For the specific slip geometry of two sets of coplanar systems (a total of four systems) in fcc metals, the range of dislocation networks in boundaries aligned with one of the two active slip planes is predicted from the Frank equation for boundaries free of long-range elastic stresses. Detailed...... by dislocation reactions. Cross slip plays a role in the boundary formation process....

  11. Experimental characterization of dislocations in deformation induced planar boundaries of rolled aluminium

    DEFF Research Database (Denmark)

    Hong, Chuanshi; Huang, Xiaoxu; Winther, Grethe

    2012-01-01

    Dislocations in 2 geometrically necessary boundaries in a grain near the 45°-ND rotated cube orientation in 10% rolled 99.996% pure Al were investigated by detailed transmission electron microscopy. In these two boundaries dislocations with all six Burgers vectors of the ½<110> type expected for ...... of which one was a Lomer lock formed by two other dislocation sets. This type of boundary contains dislocations coming from both of the slip planes expected active....

  12. Dislocation Enhancement of Seismic-Frequency Attenuation: Subgrain Boundary Diffusion and Triggered, Critical Emission of Dislocations

    Science.gov (United States)

    Cooper, R. F.; McCarthy, C.

    2012-12-01

    Combined compressional creep and (Young's-modulus) attenuation experiments on polycrystalline ice-I (200 ≤ T[K] ≤ 260; 3 ≤ d[μm] ≤ 500; σmean = 1MPa and Δσ = 0.16MPa applied in a frequency range 10-4 ≤ ν[Hz] ≤ 10-1) demonstrate the attenuation behavior associated with the seismic attenuation band and the "high-temperature background," i.e., a power-law response Q-1 ∝ ν-m with m ~ 0.33. This response has, in general, been associated with grain boundary sliding rate-limited by atomic diffusion [e.g., 1-3], a mechanism that is very sensitive to grain size. In our experiments, however, with a grain size variation ~102, the attenuation response is independent of grain size, to first order. Scrutiny of the physics suggests that the attenuation is effected primarily by diffusive relaxation of subgrain boundaries [4, 5], the size of which, in materials deforming by a dislocation mechanism (as is the ice in our experiments), is set by the deviatoric stress [6, 7]. Applying the diffusion-effected physics to the subgrain size matches the universal scaling [e.g., 3] for materials that are linear-viscoelastic. Our ice specimens, however, demonstrate modest non-linearity, resulting in greater attenuation than that associated with the diffusion process [cf. 8] and yet retain the power-law form for attenuation, including the same slope m. The result is consistent with "self-organized critical" behavior in dislocation emission [9, 10] and the physics overall can be understood via models of self-similar scaling of crystalline (effective) viscosity [e.g., 11]. The potential application to seismic studies is profound: for example, if the upper mantle of Earth is convecting via a dislocation-creep or dislocation-accommodated grain-boundary-sliding mechanism, then the attenuation response is related not to the grain size, but rather to the subgrain structure associated with the creep of the rock. Thus, seismic attenuation measurements may well be useful for

  13. Stability and motion of low angle dislocation boundaries in precipitation hardened crystals

    Czech Academy of Sciences Publication Activity Database

    Holec, David; Dlouhý, Antonín

    2005-01-01

    Roč. 482, - (2005), s. 159-162 ISSN 0255-5476 Institutional research plan: CEZ:AV0Z20410507 Keywords : Low angle dislocation boundary * precipitation hardening * dislocation motion Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.399, year: 2005

  14. Dislocation content of geometrically necessary boundaries aligned with slip planes in rolled aluminium

    DEFF Research Database (Denmark)

    Hong, Chuanshi; Huang, Xiaoxu; Winther, Grethe

    2013-01-01

    Previous studies have revealed that dislocation structures in metals with medium-to-high stacking fault energy, depend on the grain orientation and therefore on the slip systems. In the present work, the dislocations in eight slip-plane-aligned geometrically necessary boundaries (GNBs) in three g...

  15. Simulations of dislocation pile-ups at assymetric tilt boundaries in aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Valone, Steven [Los Alamos National Laboratory; Wang, Jian M [Los Alamos National Laboratory; Hoagland, Richard C [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory

    2011-01-21

    Materials deformation processes are increasingly approachable through the both conventional and accelerated molecular dynamics. In one deformation process, dislocation pile-up at a grain boundary, a greater understanding is required as to how dislocations transmit through grain boundaries, causing plastic deformation, or reflect and reconstruct the grain boundary, but with no macroscopic deformation. Here dislocation pile-ups in an alwninum bicrystal with an asymmetric tilt grain boundary are simulated atomistically, introducing effects of dislocation interactions beyond linear elastic ones. The observed responses as functions of the number of explicitly modeled dislocations and the magnitude of the applied stress are discussed. Typical conditions for the simulations consist of thermal relaxation room temperature, five active dislocations inserted within a 6.5-million-atom cell, and an additional fourteen dislocations represented within the atomistic simulation by their elastic strain fields. The dislocations are initially distributed according to linear elastic estimates of their positions in a double-ended pile-up from a chosen far-field stress. The whole cell is allowed to relax according to a procedure to be described. In the ensuing simulations, the system is propagated for some substantial period of time (lOs of ps), followed by small increments of strain. After a number of such increments, we observe all of the anticipated events. Usually several of the closest dislocations are absorbed into the grain boundary, resulting in varying amounts of reconstruction. Reflections from the boundary are common and show a strong dependence on sample thickness. Transmission events are seen on both slip systems in the other grain. The particulars of these events will be described as well.

  16. Partitioning of water between point defects, dislocations, and grain boundaries in olivine

    Science.gov (United States)

    Tielke, J. A.; Mecklenburgh, J.; Mariani, E.; Wheeler, J.

    2017-12-01

    Estimates of the storage capacity of water in the interior of the Earth and other terrestrial planets vary significantly. One interpretation is that water in planetary interiors exists primarily as hydrogen ions, dissociated from liquid water, that are associated with point defects in the crystal structure of nominally anhydrous minerals. However, dislocations and grain boundaries may contribute significantly to the storage capacity of water in planetary interiors, but hydrogen concentrations in dislocations and grain boundaries are difficult to quantify. To measure the water storage capacity of dislocations and grain boundaries, we are analyzing results from high-temperature and high-pressure experiments where deuterium, a stable isotope of hydrogen, was incorporated into olivine, the dominate phase in the upper mantle. Compared to hydrogen, deuterium concentrations can be determined at much higher spatial resolution using secondary-ion mass spectroscopy. The concentration of deuterium in the samples will also be quantified using Fourier transform infrared spectroscopy for comparison to results for hydrogen-bearing olivine. The spatial distribution of regions with different densities of geometrically-necessary dislocations and the locations of grain boundaries will be determined using electron-backscatter diffraction (EBSD) analyses. Correlation of the concentration of deuterium with dislocation densities and grain boundaries will be used to examine the partitioning of water-derived species between the different types of defects. Ultimately, these data will be used to place more realistic bounds on the storage capacity of water in the interior of Earth and of other terrestrial planets.

  17. Atomic simulations of dislocation emission from Cu/Cu and Co/Cu grain boundaries

    International Nuclear Information System (INIS)

    Yuasa, Motohiro; Nakazawa, Takumi; Mabuchi, Mamoru

    2010-01-01

    Research highlights: → Co/Cu bicrystals have both E structures and stacking faults only in the Cu phase. → Dislocations tend to be emitted from the stacking faults in Co/Cu bicrystals. → Large disorder around the stacking faults accelerates the atomic shuffling. → Atomic shuffling behavior strongly affects dislocation emission in Co/Cu bicrystals. - Abstract: Molecular dynamics simulations of creep tests have been performed on Cu/Cu single-phase bicrystals and Co/Cu two-phase bicrystals to investigate the dislocation emission from grain boundaries. In the Co/Cu bicrystals, both E structures and stacking faults were generated only in the Cu grain near the boundary. Dislocations were emitted only from the stacking faults, not from the E structures, in the Co/Cu bicrystals. The stacking faults in the Co/Cu bicrystals did not necessarily enhance the dislocation emission as readily as those in the Cu/Cu bicrystals. The incoherence between Co and Cu gave rise to the complicated defect structures at and near the Co/Cu boundary, and thus distinctive atomic shuffling mechanisms occurred. This affected the dislocation emission behavior of the Co/Cu bicrystals.

  18. Dislocation reactions, grain boundaries, and irreversibility in two-dimensional lattices using topological tweezers.

    Science.gov (United States)

    Irvine, William T M; Hollingsworth, Andrew D; Grier, David G; Chaikin, Paul M

    2013-09-24

    Dislocations, disclinations, and grain boundaries are topological excitations of crystals that play a key role in determining out-of-equilibrium material properties. In this article we study the kinetics, creation, and annihilation processes of these defects in a controllable way by applying "topological tweezers," an array of weak optical tweezers which strain the lattice by weakly pulling on a collection of particles without grabbing them individually. We use topological tweezers to deterministically control individual dislocations and grain boundaries, and reversibly create and destroy dislocation pairs in a 2D crystal of charged colloids. Starting from a perfect lattice, we exert a torque on a finite region and follow the complete step-by-step creation of a disoriented grain, from the creation of dislocation pairs through their reactions to form a grain boundary and their reduction of elastic energy. However, when the grain is rotated back to its original orientation the dislocation reactions do not retrace. Rather, the process is irreversible; the grain boundary expands instead of collapsing.

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

    Science.gov (United States)

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

    2017-09-01

    Ice has a very high plastic anisotropy with easy dislocation glide on basal planes, while glide on non-basal planes is much harder. Basal glide involves dislocations with the Burgers vector b = 〈a〉, while glide on non-basal planes can involve dislocations with b = 〈a〉, b = [c], and b = 〈c + a〉. During the natural ductile flow of polar ice sheets, most of the deformation is expected to occur by basal slip accommodated by other processes, including non-basal slip and grain boundary processes. However, the importance of different accommodating processes is controversial. The recent application of micro-diffraction analysis methods to ice, such as X-ray Laue diffraction and electron backscattered diffraction (EBSD), has demonstrated that subgrain boundaries indicative of non-basal slip are present in naturally deformed ice, although so far the available data sets are limited. In this study we present an analysis of a large number of subgrain boundaries in ice core samples from one depth level from two deep ice cores from Antarctica (EPICA-DML deep ice core at 656 m of depth) and Greenland (NEEM deep ice core at 719 m of depth). EBSD provides information for the characterization of subgrain boundary types and on the dislocations that are likely to be present along the boundary. EBSD analyses, in combination with light microscopy measurements, are presented and interpreted in terms of the dislocation slip systems. The most common subgrain boundaries are indicative of basal 〈a〉 slip with an almost equal occurrence of subgrain boundaries indicative of prism [c] or 〈c + a〉 slip on prism and/or pyramidal planes. A few subgrain boundaries are indicative of prism 〈a〉 slip or slip of 〈a〉 screw dislocations on the basal plane. In addition to these classical polygonization processes that involve the recovery of dislocations into boundaries, alternative mechanisms are discussed for the formation of subgrain boundaries that are not related to the

  20. Dislocation

    Science.gov (United States)

    ... forcefully on a body part, such as your hip or shoulder. Heredity. Some people are born with ligaments that are looser and more prone to injury ... accidents. These are the most common cause of hip dislocations, especially for people ... the muscles, ligaments and tendons that reinforce the injured joint Nerve ...

  1. In-situ transmission electron microscopy : on moving dislocations and mobile grain boundaries

    NARCIS (Netherlands)

    De Hosson, J. T. M.; Soer, W.

    This paper delineates the possibilities of utilizing in situ transmission electron microscopy to unravel dislocation-g rain boundary interactions. In situ nanoindentation experiments have been conducted in TEM on ultrafine-grained Al and Al-Mg films with varying Mg contents. The observed propagation

  2. In situ TEM nanoindentation and dislocation-grain boundary interactions : a tribute to David Brandon

    NARCIS (Netherlands)

    de Hosson, J.T.M.; Soer, W.A.; Minor, A.M.; Shan, Z.W.; Stach, E.A.; Asif, S.A.S.; Warren, O.L.

    2006-01-01

    As a tribute to the scientific work of Professor David Brandon, this paper delineates the possibilities of utilizing in situ transmission electron microscopy to unravel dislocation-grain boundary interactions. In particular, we have focused on the deformation characteristics of Al-Mg films. To this

  3. Distinct error-correcting and incidental learning of location relative to landmarks and boundaries.

    Science.gov (United States)

    Doeller, Christian F; Burgess, Neil

    2008-04-15

    Associative reinforcement provides a powerful explanation of learned behavior. However, an unproven but long-held conjecture holds that spatial learning can occur incidentally rather than by reinforcement. Using a carefully controlled virtual-reality object-location memory task, we formally demonstrate that locations are concurrently learned relative to both local landmarks and local boundaries but that landmark-learning obeys associative reinforcement (showing "overshadowing" and "blocking" or "learned irrelevance"), whereas boundary-learning is incidental, showing neither overshadowing nor blocking nor learned irrelevance. Crucially, both types of learning occur at similar rates and do not reflect differences in levels of performance, cue salience, or instructions. These distinct types of learning likely reflect the distinct neural systems implicated in processing of landmarks and boundaries: the striatum and hippocampus, respectively [Doeller CF, King JA, Burgess N (2008) Proc Natl Acad Sci USA 105:5915-5920]. In turn, our results suggest the use of fundamentally different learning rules by these two systems, potentially explaining their differential roles in procedural and declarative memory more generally. Our results suggest a privileged role for surface geometry in determining spatial context and support the idea of a "geometric module," albeit for location rather than orientation. Finally, the demonstration that reinforcement learning applies selectively to formally equivalent aspects of task-performance supports broader consideration of two-system models in analyses of learning and decision making.

  4. Regularized boundary integral representations for dislocations and cracks in smart media

    International Nuclear Information System (INIS)

    Rungamornrat, J; Senjuntichai, T

    2009-01-01

    This paper presents a complete set of singularity-reduced boundary integral relations for isolated discontinuities embedded in three-dimensional infinite media. The development is carried out within a broad context that allows the treatment of a well-known class of smart media such as linear piezoelectric, linear piezomagnetic and linear piezoelectromagnetic materials. In addition, resulting boundary integral representations are applicable to general discontinuities of arbitrary geometry and possessing a general jump distribution. The latter aspect allows the treatment of two special kinds of discontinuities: dislocations and cracks. The most attractive feature of the current development is that all integral relations for field quantities such as state variables and their gradients, the body flux, and the generalized interaction energy produced by dislocations are expressed only in terms of line integrals over the dislocation loops and, for cracks, the key governing boundary integral equation is established in a symmetric weak form and contains only weakly singular kernels of O(1/r). Results for the former case are fundamental and useful in the context of dislocation mechanics and modeling while the resulting weakly singular, weak form integral equation constitutes a basis for the development of a well-known numerical technique, called a symmetric Galerkin boundary element method (SGBEM), for analysis of cracked bodies. The weakly singular nature of such an integral equation allows low order interpolations to be used in the numerical approximation. The key ingredient for achieving such development of integral representations is the use of certain special decompositions in the derivative-transferring process via Stokes's theorem. Existence of such decompositions is ensured by a careful consideration of the singularity nature of the kernels, and a particular solution of the weakly singular functions involved is obtained by solving a system of partial differential

  5. Asymptotic expressions for the nearest and furthest dislocations in a pile-up against a grain boundary

    KAUST Repository

    Hall, Cameron L.

    2010-10-14

    In 1965, Armstrong and Head explored the problem of a pile-up of screw dislocations against a grain boundary. They used numerical methods to determine the positions of the dislocations in the pile-up and they were able to fit approximate formulae for the locations of the first and last dislocations. These formulae were used to gain insights into the Hall-Petch relationship. More recently, Voskoboinikov et al. used asymptotic techniques to study the equivalent problem of a pile-up of a large number of screw dislocations against a bimetallic interface. In this paper, we extend the work of Voskoboinikov et al. to construct systematic asymptotic expressions for the formulae proposed by Armstrong and Head. The further extension of these techniques to more general pile-ups is also outlined. As a result of this work, we show that a pile-up against a grain boundary can become equivalent to a pile-up against a locked dislocation in the case where the mismatch across the boundary is small. © 2010 Taylor & Francis.

  6. Interactions between Lattice Dislocations and Grain Boundaries in Ni3Al Investigated by Means of In Situ TEM and Computer Modelling Experiments

    NARCIS (Netherlands)

    Pestman, B.J.; Hosson, J.Th.M. De

    1992-01-01

    The interaction between lattice dislocations and grain boundaries in Ni3Al has been investigated by means of in situ TEM deformation experiments. The interaction between screw dislocations and a coherent twin boundary could be analyzed in detail. The interaction mechanism found experimentally was

  7. Effects of Grain Boundaries and Dislocation Cell Walls on Void Nucleation and Growth in Aluminium during Fast Neutron Irradiation

    DEFF Research Database (Denmark)

    Horsewell, Andy; Rahman, F. A.; Singh, Bachu Narain

    1983-01-01

    High purity aluminium irradiated to fluences between 2 multiplied by 10**2**1 and 1 multiplied by 10**2**4 n. m** minus **2 (E greater than 1 Mev) at 120 degree C has been investigated by TEM. A void denuded zone is seen both at grain boundaries and dislocation cell walls. Enhanced void formation...

  8. Orientation dependence of grain-boundary energy in metals in the view of a pseudoheterophase dislocation core model

    International Nuclear Information System (INIS)

    Missol, W.

    1976-01-01

    A new dislocation model for symmetric tilt grain boundaries was developed as a basis for deriving the quantitative dependence of grain-boundary energy upon misorientation angle in the form of an expression similar to that given by Read and Shockley [Phys. Rev. 78: 275(1950)]. The range of applicability of this equation was extended to over 20 degrees. A comparison of theory and experiment was made for Bi, Ag, Cu, and Fe--Si 3 percent in the teen-degree range of misorientation angles and for Au, α-Fe, Mo, and W in the high-angle range

  9. Nucleation of Helium Bubbles on Dislocations, Dislocation Networks and Dislocation in Grain Boundaries during 600 MeV Proton Irradiation of Aluminium

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Green, W.V.;

    1984-01-01

    Samples of high-purity aluminium were irradiated with 600 MeV protons at temperatures in the range 130 to 433°C; in these experiments 615 and 125 appm of hydrogen and helium, respectively, are produced per dpa. Bubble formation and growth at grain boundaries and in the zone adjacent to the bubble...

  10. Mechanical properties of ceria nanorods and nanochains; the effect of dislocations, grain-boundaries and oriented attachment.

    Science.gov (United States)

    Sayle, Thi X T; Inkson, Beverley J; Karakoti, Ajay; Kumar, Amit; Molinari, Marco; Möbus, Günter; Parker, Stephen C; Seal, Sudipta; Sayle, Dean C

    2011-04-01

    We predict that the presence of extended defects can reduce the mechanical strength of a ceria nanorod by 70%. Conversely, the pristine material can deform near its theoretical strength limit. Specifically, atomistic models of ceria nanorods have been generated with full microstructure, including: growth direction, morphology, surface roughening (steps, edges, corners), point defects, dislocations and grain-boundaries. The models were then used to calculate the mechanical strength as a function of microstructure. Our simulations reveal that the compressive yield strengths of ceria nanorods, ca. 10 nm in diameter and without extended defects, are 46 and 36 GPa for rods oriented along [211] and [110] respectively, which represents almost 10% of the bulk elastic modulus and are associated with yield strains of about 0.09. Tensile yield strengths were calculated to be about 50% lower with associated yield strains of about 0.06. For both nanorods, plastic deformation was found to proceed via slip in the {001} plane with direction --a primary slip system for crystals with the fluorite structure. Dislocation evolution for the nanorod oriented along [110] was nucleated via a cerium vacancy present at the surface. A nanorod oriented along [321] and comprising twin-grain boundaries with {111} interfacial planes was calculated to have a yield strength of about 10 GPa (compression and tension) with the grain boundary providing the vehicle for plastic deformation, which slipped in the plane of the grain boundary, with an associated slip direction. We also predict, using a combination of atomistic simulation and DFT, that rutile-structured ceria is feasible when the crystal is placed under tension. The mechanical properties of nanochains, comprising individual ceria nanoparticles with oriented attachment and generated using simulated self-assembly, were found to be similar to those of the nanorod with grain-boundary. Images of the atom positions during tension and compression

  11. Characterisation of multicrystalline silicon solar cells. Development of characterisation method for the combined effect of dislocations and grain boundaries on the minority carrier lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Stokkan, Gaute

    2004-07-01

    The thesis has sections on theoretical background, mathematical models, experimental work such as lifetime measurements, dislocation density and grain boundary mapping, simulation of electrical activity mapping and conclusions and future work. Various mathematical models and nafion surface passivation are studied as well.

  12. Dislocation interaction with a .SIGMA.=3 grain boundary by .I.in-situ./I. TEM

    Czech Academy of Sciences Publication Activity Database

    Vystavěl, Tomáš; Jacques, A.; Gemperle, Antonín; Gemperlová, Juliana; George, A.

    294-296, - (1999), s. 397-400 ISSN 0255-5476. [Intergranular and Interphase Boundaries in Materials(iib`98). Praha, 06.07.1998-09.07.1998] R&D Projects: GA AV ČR IAA1010702; GA ČR GA202/98/1281 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.981, year: 1999

  13. Reactions of slip dislocations with twin boundary in Fe-Si bicrystals

    Czech Academy of Sciences Publication Activity Database

    Gemperle, Antonín; Zárubová, Niva; Gemperlová, Juliana

    2005-01-01

    Roč. 40, - (2005), 3247-3254 ISSN 0022-2461 R&D Projects: GA ČR GA202/01/0670 Institutional research plan: CEZ:AV0Z10100520 Keywords : in situ TEM * grain boundary * plastic deformation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.901, year: 2005

  14. Formation of disorientations in dislocation structures during plastic deformation

    DEFF Research Database (Denmark)

    Pantleon, W.

    2002-01-01

    Disorientations developing during plastic deformation in dislocation structures are investigated. Based on expected mechanisms for the formation of different types of dislocation boundaries (statistical trapping of dislocations or differently activated slip systems) the formation of the disorient......Disorientations developing during plastic deformation in dislocation structures are investigated. Based on expected mechanisms for the formation of different types of dislocation boundaries (statistical trapping of dislocations or differently activated slip systems) the formation...

  15. Cyclic softening based on dislocation annihilation at sub-cell boundary for SA333 Grade-6 C-Mn steel

    Science.gov (United States)

    Bhattacharjee, S.; Dhar, S.; Acharyya, S. K.; Gupta, S. K.

    2018-01-01

    In this work, the response of SA333 Grade-6 C-Mn steel subjected to uniaxial and in-phase biaxial tension-torsion cyclic loading is experimented and an attempt is made to model the material behaviour. Experimentally observed cyclic softening is modelled based on ‘dislocation annihilation at low angle grain boundary’, while Ohno-Wang kinematic hardening rule is used to simulate the stress-strain hysteresis loops. The relevant material parameters are extracted from the appropriate experimental results and metallurgical investigations. The material model is plugged as user material subroutine into ABAQUS FE platform to simulate pre-saturation low cycle fatigue loops with cyclic softening and other cyclic plastic behaviour under prescribed loading. The stress-strain hysteresis loops and peak stress with cycles were compared with the experimental results and good agreements between experimental and simulated results validated the material model.

  16. Subtalar dislocation

    International Nuclear Information System (INIS)

    El-Khoury, G.Y.; Yousefzadeh, D.K.; Mulligan, G.M.; Moore, T.E.

    1982-01-01

    Over a period of three years we have seen nine patients with subtalar dislocation, all of whom sustained violent trauma to the region of the ankle and hind foot. All but one patient were males. Clinically a subtalar dislocation resembles a complicated fracture dislocation of the ankle but a definitive diagnosis can only be made radiographically. The mechanism of injury and radiographic features of this injury are discussed. (orig.)

  17. Jaw Dislocation

    Science.gov (United States)

    ... used to temporarily stabilize the jaw after a fracture or dislocation. More Information Mouth Healthy Resources In This Article Figure 1 Putting a Dislocated Jaw Back in Place Figure 2 Barton Bandage Urgent Dental Problems Introduction to Urgent Dental Problems Fractured, Loosened, ...

  18. The movement of screw dislocations in tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Tian Xiaogeng; Woo Chungho

    2004-03-25

    Using Acland potential for tungsten, the movement of 1/2a<1 1 1> screw dislocation under shear stress was investigated by molecular dynamics simulation. Equilibrated core structure was obtained by relaxation of screw dislocation with proper boundary conditions. We found that the equilibrium dislocation core has three-fold symmetry and spread out in three <1 1 2> direction on {l_brace}1 1 0{r_brace} planes. The screw dislocation core could not keep the original shape when the shear stress applied. The dislocation could not move until the shear stress became large enough. The dislocation moved in zigzag when the shear stress neared the Peierls stress. When the shear stress became larger, the dislocation moved in zigzag at the beginning and than moved almost in straight line in [2-bar11] direction. The large shear stress applied, the long distance moved before the dislocation stilled in z-direction and the large velocity in y-direction.

  19. Perilunate Dislocation

    Directory of Open Access Journals (Sweden)

    John Jiao

    2016-09-01

    Full Text Available History of present illness: A 25-year-old female presented to the emergency department with left wrist pain following a fall off a skateboard. The patient fell on her outstretched left wrist with the wrist dorsiflexed and reported immediate sharp pain to her left wrist that was worse with movement. She denied other trauma. Significant findings: In the left lateral wrist x-ray, the lunate (outlined in blue is dislocated from the rest of the wrist bones (yellow line but still articulates with the radius (red line. The capitate (yellow line does not sit within the distal articulation of the lunate and is displaced dorsally. Additionally, a line drawn through the radius and lunate (green line fails to intersect with the capitate. This is consistent with a perilunate dislocation. This is compared to a lunate dislocation, where the lunate itself is displaced and turned ventrally (spilled teacup and the proximal aspect does not articulate with the radius. Discussion: A perilunate dislocation is a significant closed wrist injury that is easily missed on standard anterior-posterior imaging. These dislocations are relatively rare, involving only 7% of all carpal injuries and are associated with high-energy trauma onto a hyperextended wrist, such as falls from a height, motor vehicle accidents, and sports injuries.1 An untreated perilunate dislocation is associated with high risk of chronic carpal instability and post-traumatic arthritis. If the mechanism of injury is sufficient to suspect perilunate dislocation, multiple radiographic views of the wrist should be ordered. Patients should receive prompt orthopedic consultation for open reduction and ligamentous repair. Even after successful identification and subsequent surgical repair, median nerve neuropathy and post-traumatic arthritis are frequent.2-3

  20. Lunate Dislocation

    Directory of Open Access Journals (Sweden)

    Jonathan Peña

    2017-01-01

    Full Text Available History of present illness: A 28-year-old right-handed male presented to the ED after he fell onto his outstretched right hand after being thrown from his motorcycle at highway speeds. He complained of right wrist pain. On exam, he had a visible deformity of his right wrist with diffuse tenderness to palpation over the wrist. Sensation was intact and he had 2+ radial and ulnar pulses. Significant findings: Plain film of the right wrist showed the classic “spilled teacup” consistent with a lunate dislocation. There is a loss of the normal articulation between the distal radius and lunate (white curved highlights represent expected points of articulation. Discussion: The most common mechanism leading to a dislocation of lunate is a fall onto an outstretched hand with the wrist in extension. Damage to the ligamentous infrastructure (commonly the dorsal radiolunate ligament causes destabilization.1 Lunate dislocations are distinguished from perilunate dislocations by assessing for the preservation of the articulation between the lunate and distal radius. In lunate dislocations, this articulation is disrupted leading to the classic “spilled teacup” appearance as seen above. However, if the articulation between the distal radius and lunate is preserved, but there is displacement of the carpal bones (eg, scaphoid, triquetrum, etc, then the dislocation is referred to as a perilunate dislocation. Plain film radiography oriented in the lateral view is typically the first-line modality for diagnosis. However, advanced imaging such as computed tomography or magnetic resonance imaging may be required to rule out fracture. It is important to keep in mind that the lunate receives its blood supply distally from the anterior interosseous artery; therefore, any injury (eg, fracture that disrupts perfusion places the patient at risk for avascular necrosis.2 As with all orthopedic upper extremity injuries, a thorough neurologic exam should be performed

  1. Theory of interacting dislocations on cylinders.

    Science.gov (United States)

    Amir, Ariel; Paulose, Jayson; Nelson, David R

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  2. Exploring the Limit of Dislocation Based Plasticity in Nanostructured Metals

    DEFF Research Database (Denmark)

    Hughes, D. A.; Hansen, Niels

    2014-01-01

    A twofold decrease to an unexplored scale of 5 nm was produced in Cu by applying a large sliding load in liquid nitrogen. Statistical and universal scaling analyses of deformation induced high angle boundaries, dislocation boundaries, and individual dislocations observed by high resolution electr...

  3. Extracting dislocations and non-dislocation crystal defects from atomistic simulation data

    International Nuclear Information System (INIS)

    Stukowski, Alexander; Albe, Karsten

    2010-01-01

    We describe a novel method for extracting dislocation lines from atomistic simulation data in a fully automated way. The dislocation extraction algorithm (DXA) generates a geometric description of dislocation lines contained in an arbitrary crystalline model structure. Burgers vectors are determined reliably, and the extracted dislocation network fulfills the Burgers vector conservation rule at each node. All remaining crystal defects (grain boundaries, surfaces, etc), which cannot be represented by one-dimensional dislocation lines, are output as triangulated surfaces. This geometric representation is ideal for visualization of complex defect structures, even if they are not related to dislocation activity. In contrast to the recently proposed on-the-fly dislocation detection algorithm (ODDA) Stukowski (2010 Modelling Simul. Mater. Sci. Eng. 18 015012) the new method is extremely robust. While the ODDA was designed for a computationally efficient on-the-fly analysis, the DXA method enables a detailed analysis of dislocation lines even in highly distorted crystal regions, as they occur, for instance, close to grain boundaries or in dense dislocation networks

  4. Misoriented dislocation substructures and the fracture of polycrystalline Cu-Al alloys

    Science.gov (United States)

    Koneva, N. A.; Trishkina, L. I.; Cherkasova, T. V.; Kozlov, E. V.

    2016-10-01

    The evolution of the dislocation substructure in polycrystalline Cu-Al alloys with various grain sizes is studied during deformation to failure. A relation between the fracture of the alloys and the forming misorientation dislocation substructures is revealed. Microcracks in the alloy are found to form along grain boundaries and the boundaries of misoriented dislocation cells and microtwins.

  5. Incidental renal neoplasms

    DEFF Research Database (Denmark)

    Rabjerg, Maj; Mikkelsen, Minne Nedergaard; Walter, Steen

    2014-01-01

    On the basis of associations between tumor size, pathological stage, histological subtype and tumor grade in incidentally detected renal cell carcinoma vs symptomatic renal cell carcinoma, we discussed the need for a screening program of renal cell carcinoma in Denmark. We analyzed a consecutive...... series of 204 patients with renal tumors in 2011 and 2012. The tumors were classified according to detection mode: symptomatic and incidental and compared to pathological parameters. Eighty-nine patients (44%) were symptomatic, 113 (55%) were incidental. Information was not available in two patients...

  6. Glenoid Dysplasia in the Recurrent Shoulder Dislocation: A Case Report

    Directory of Open Access Journals (Sweden)

    Hamza Sucuoglu

    2016-02-01

    Full Text Available Glenoid dysplasia, which is often ignored, is a rare developmental anomaly. In most cases the patients remain asymptomatic. Although glenoid dysplasia has been diagnosed by incidentally on chest radiograph, also it has been described because of the developing instability of shoulder joint. Our young male patient who has recurrent dislocation of the shoulder-joint 4-5 times a year for last 5 years, dislocation has been reduced in the emergency department and he has been discharged from hospital with shoulder strap and rest. Finally when he admitted to our outpatient clinic with recurrent shoulder dislocation, the diagnosis of glenoid dysplasia is revealed by X-ray examination. We present the diagnose of glenoid dysplasia with clinical and radiological findings which should be kept in mind in patients with recurrent dislocations of shoulder as in our case.

  7. How grain boundaries affect the efficiency of poly-CdTe solar-cells: A fundamental atomic-scale study of grain boundary dislocation cores using CdTe bi-crystal thin films.

    Energy Technology Data Exchange (ETDEWEB)

    Klie, Robert [Univ. of Illinois, Chicago, IL (United States)

    2016-10-25

    It is now widely accepted that grain boundaries in poly-crystalline CdTe thin film devices have a detrimental effect on the minority carrier lifetimes, the open circuit voltage and therefore the overall solar-cell performance. The goal of this project was to develop a fundamental understanding of the role of grain boundaries in CdTe on the carrier life-time, open-circuit voltage, Voc, and the diffusion of impurities. To achieve this goal, i) CdTe bi-crystals were fabricated with various misorientation angels, ii) the atomic- and electronic structures of the grain boundaries were characterized using scanning transmission electron microscopy (STEM), and iii) first-principles density functional theory modeling was performed on the structures determined by STEM to predict the grain boundary potential. The transport properties and minority carrier lifetimes of the bi-crystal grain boundaries were measured using a variety of approaches, including TRPL, and provided feedback to the characterization and modeling effort about the effectiveness of the proposed models.

  8. The gauge theory of dislocations: A nonuniformly moving screw dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Lazar, Markus, E-mail: lazar@fkp.tu-darmstadt.d [Emmy Noether Research Group, Department of Physics, Darmstadt University of Technology, Hochschulstr. 6, D-64289 Darmstadt (Germany); Department of Physics, Michigan Technological University, Houghton, MI 49931 (United States)

    2010-07-05

    We investigate the nonuniform motion of a straight screw dislocation in infinite media in the framework of the translational gauge theory of dislocations. The equations of motion are derived for an arbitrarily moving screw dislocation. The fields of the elastic velocity, elastic distortion, dislocation density and dislocation current surrounding the arbitrarily moving screw dislocation are derived explicitly in the form of integral representations. We calculate the radiation fields and the fields depending on the dislocation velocities.

  9. Crane. Incidental Classroom Instruction 20295

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Richard Jennings [Los Alamos National Laboratory

    2016-04-01

    The purpose of this course is to introduce safe hoisting and rigging practices to personnel who are attempting to become LANL incidental crane operators and to review and refresh safe hoisting and rigging practices with existing incidental crane operators.

  10. Mobilities and dislocation energies of planar faults in an ordered ...

    Indian Academy of Sciences (India)

    D019) phase with an axial ratio less than the ideal. Mobilities and dislocation energies of various planar faults viz. antiphase boundaries (APBs), superlattice intrinsic stacking faults (SISFs) and complex stacking faults (CSFs) have been ...

  11. Primary traumatic patellar dislocation

    Directory of Open Access Journals (Sweden)

    Tsai Chun-Hao

    2012-06-01

    Full Text Available Abstract Acute traumatic patellar dislocation is a common injury in the active and young adult populations. MRI of the knee is recommended in all patients who present with acute patellar dislocation. Numerous operative and non-operative methods have been described to treat the injuries; however, the ideal management of the acute traumatic patellar dislocation in young adults is still in debate. This article is intended to review the studies to the subjects of epidemiology, initial examination and management.

  12. Kneecap dislocation - aftercare

    Science.gov (United States)

    Patellar subluxation - aftercare; Patellofemoral subluxation - aftercare; Kneecap subluxation - aftercare ... is twisting motion or a sudden turn. Kneecap subluxation or dislocation may occur more than once. The ...

  13. High-temperature discrete dislocation plasticity

    Science.gov (United States)

    Keralavarma, S. M.; Benzerga, A. A.

    2015-09-01

    A framework for solving problems of dislocation-mediated plasticity coupled with point-defect diffusion is presented. The dislocations are modeled as line singularities embedded in a linear elastic medium while the point defects are represented by a concentration field as in continuum diffusion theory. Plastic flow arises due to the collective motion of a large number of dislocations. Both conservative (glide) and nonconservative (diffusion-mediated climb) motions are accounted for. Time scale separation is contingent upon the existence of quasi-equilibrium dislocation configurations. A variational principle is used to derive the coupled governing equations for point-defect diffusion and dislocation climb. Superposition is used to obtain the mechanical fields in terms of the infinite-medium discrete dislocation fields and an image field that enforces the boundary conditions while the point-defect concentration is obtained by solving the stress-dependent diffusion equations on the same finite-element grid. Core-level boundary conditions for the concentration field are avoided by invoking an approximate, yet robust kinetic law. Aspects of the formulation are general but its implementation in a simple plane strain model enables the modeling of high-temperature phenomena such as creep, recovery and relaxation in crystalline materials. With emphasis laid on lattice vacancies, the creep response of planar single crystals in simple tension emerges as a natural outcome in the simulations. A large number of boundary-value problem solutions are obtained which depict transitions from diffusional to power-law creep, in keeping with long-standing phenomenological theories of creep. In addition, some unique experimental aspects of creep in small scale specimens are also reproduced in the simulations.

  14. Dislocation model of fracture

    International Nuclear Information System (INIS)

    Kull', L.M.

    1987-01-01

    Papers dealing with study on mechanisms of submicricrack formation and propagation using dislocation representations are analyzed. Cases of brittle and ductile fracture of materials as well as models of dislocationless (amorphous) zone at the growing crack tip are considered. Dislocation models of fracture may be used when studying the processes of deformation and accumulation of damages in elements of nuclear facilities

  15. Orientation dependence of the dislocation microstructure in compressed body-centered cubic molybdenum

    International Nuclear Information System (INIS)

    Wang, S.; Wang, M.P.; Chen, C.; Xiao, Z.; Jia, Y.L.; Li, Z.; Wang, Z.X.

    2014-01-01

    The orientation dependence of the deformation microstructure has been investigated in commercial pure molybdenum. After deformation, the dislocation boundaries of compressed molybdenum can be classified, similar to that in face-centered cubic metals, into three types: dislocation cells (Type 2), and extended planar boundaries parallel to (Type 1) or not parallel to (Type 3) a (110) trace. However, it shows a reciprocal relationship between face-centered cubic metals and body-centered cubic metals on the orientation dependence of the deformation microstructure. The higher the strain, the finer the microstructure is and the smaller the inclination angle between extended planar boundaries and the compression axis is. - Highlights: • A reciprocal relationship between FCC metals and BCC metals is confirmed. • The dislocation boundaries can be classified into three types in compressed Mo. • The dislocation characteristic of different dislocation boundaries is different

  16. Incidental malignant periocular tumors

    Directory of Open Access Journals (Sweden)

    Thabit Odat

    2016-04-01

    Full Text Available AIM: To study the incidence, epidemiology, and clinical characteristics of incidental malignant periocular tumors at the royal medical services hospitals of Jordan.METHODS: Retrospective medical charts of 327 patients with malignant periocular tumor diagnosis at Jordan military hospitals between 2004 and 2015 were reviewed. Study variables included age, gender, city where patient lived, the presenting complaint(not caused by or related to tumor, clinical and histological diagnosis, size of the tumor, location, and surgical procedure.RESULTS:A total of 327 charts reviewed, 46(14.1%patients were found to have incidental malignant periocular tumor. Males where affected more than females with a ratio of 2:1. The average age was 66.39±10.59(22-83y. The most common presenting symptom or disease was blurring of vision secondary to cataract(44%, followed by combined cataract and other associated complaints such as epiphora in 21.7%.Preliminary clinical diagnosis corresponded with histological diagnosis in 95.7% of skin cancer. The average size of the lesions was 1.04×0.85 mm2(0.2×0.2-3.0×3.0 mm2. There was no significant relationship between the maximum diameter of the tumor and age of the patient,(P=0.105. The most frequent location of tumors was the lower eyelid(30.4%followed by the medial canthus(26.1%. The follow up period ranged between 6mo and 3y(average 9.3mo.CONCLUSION: Incidental malignant periocular malignant tumors were relatively common in this study, which urges excision of any suspicious lesion particularly young patients. A prospective study is needed to investigate the reasons why some patients neglect these lesions.

  17. Dislocation substructure of mantle-derived olivine as revealed by selective chemical etching and transmission electron microscopy

    Science.gov (United States)

    Kirby, S.H.; Wegner, M.W.

    1978-01-01

    Cleaved and mechanically polished surfaces of olivine from peridotite xenoliths from San Carlos, Arizona, were chemically etched using the techniques of Wegner and Christie (1974). Dislocation etch pits are produced on all surface orientations and they tend to be preferentially aligned along the traces of subgrain boundaries, which are approximately parallel to (100), (010), and (001). Shallow channels were also produced on (010) surfaces and represent dislocations near the surface that are etched out along their lengths. The dislocation etch channel loops are often concentric, and emanate from (100) subgrain boundaries, which suggests that dislocation sources are in the boundaries. Data on subgrain misorientation and dislocation line orientation and arguments based on subgrain boundary energy minimization are used to characterize the dislocation structures of the subgrain boundaries. (010) subgrain boundaries are of the twist type, composed of networks of [100] and [001] screw dislocations. Both (100) and (001) subgrain boundaries are tilt walls composed of arrays of edge dislocation with Burgers vectors b=[100] and [001], respectively. The inferred slip systems are {001} ???100???, {100} ???001???, and {010} ???100??? in order of diminishing importance. Exploratory transmission electron microscopy is in accord with these identifications. The flow stresses associated with the development of the subgrain structure are estimated from the densities of free dislocations and from the subgrain dimensions. Inferred stresses range from 35 to 75 bars using the free dislocation densities and 20 to 100 bars using the subgrain sizes. ?? 1978 Springer-Verlag.

  18. Atomic-scale processes revealing dynamic twin boundary strengthening mechanisms in face-centered cubic materials

    International Nuclear Information System (INIS)

    Yang, Z.Q.; Chisholm, M.F.; He, L.L.; Pennycook, S.J.; Ye, H.Q.

    2012-01-01

    We report experimental investigations on interactions/reactions between dislocations and twin boundaries in Al. The absorption of screw dislocations via cross-slip and the production of stair-rods via reactions with non-screw dislocations were verified by atomic resolution imaging. Importantly, the resulting partial dislocations moving along twin boundaries can produce secondary sessile defects. These immobile defects act as obstacles to other dislocations and also serve to pin the twin boundaries. These findings show the atomic-level dynamics of the dislocation–twin boundary processes and the unique strengthening mechanism of twin boundaries in face-centered cubic metals.

  19. Appendicular joint dislocations.

    Science.gov (United States)

    Hindle, Paul; Davidson, Eleanor K; Biant, Leela C; Court-Brown, Charles M

    2013-08-01

    This study defines the incidence and epidemiology of joint dislocations and subluxations of the appendicular skeleton. All patients presenting acutely to hospital with a dislocation or subluxation of the appendicular skeleton from a defined population were included in the study. There were 974 dislocations or subluxations over one year between the 1st November 2008 and the 31st October 2009. There was an overall joint dislocation incidence of 157/10(5)/year (188/10(5)/year in males and 128/10(5)/year in females). Males demonstrated a bimodal distribution with a peak incidence of 446/10(5)/year at 15-24 years old and another of 349/10(5)/year in those over 90 years. Females demonstrate an increasing incidence from the seventh decade with a maximum incidence of 520/10(5)/year in those over 90 years. The most commonly affected joints are the glenohumeral (51.2/10(5)/year), the small joints of the hand (29.9/10(5)/year), the patellofemoral joint (21.6/10(5)/year), the prosthetic hip (19.0/10(5)/year), the ankle (11.5/10(5)/year), the acromioclavicular joint (8.9/10(5)/year) and the elbow (5.5/10(5)/year). Unlike fractures, dislocations are more common in the both the most affluent and the most socially deprived sections of the population. Joint disruptions are more common than previously estimated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Posterior Elbow Dislocation

    Directory of Open Access Journals (Sweden)

    Victoria Oppenheim

    2016-09-01

    Full Text Available History of present illness: A 15-year old female presented with left elbow pain. While competing in a high school wrestling match, she extended her left arm to brace a fall and had immediate onset of sharp pain. She denied weakness or numbness of her left arm. She had no past medical history. Significant findings: Elbow dislocations are classified by the position of the radio-ulnar joint relative to the humerus.1 Images 1, 2, and 3 show a left posterior elbow dislocation; the radius and ulna are displaced posteriorly with respect to the distal humerus. The lateral view of the elbow most clearly shows this: trochlear notch of the ulna is empty and displaced posteriorly relative to the trochlea. There is no associated fracture. Images 4 and 5 show the elbow status-post reduction, demonstrating proper alignment of the distal humerus with the radius and ulna. Discussion: Traumatic dislocations of the elbow are relatively uncommon in pediatric patients, with a peak incidence at 13 to 14 years.1 Dislocations are usually posterior and occur after forced abduction and extension of the elbow.1 It is important to evaluate for an associated fracture or avulsion, which occurs in over 50% of pediatric elbow dislocations. Fractures most commonly involve the medial epicondyle, radial head and neck, or coronoid process.1 One should also consider a neurovascular injury to the ulnar or median nerve or to the brachial artery or its branches.1 Posterior elbow dislocations should be reduced as soon as possible.1 Patients should receive adequate sedation and/or analgesia. One method of reduction is the “puller” technique, during which a practitioner stabilizes the humerus, while a second practitioner applies force against the anterior forearm, with gentle traction distally.1 Post-reduction neurovascular reassessment is important. After successful reduction, patients can be immobilized in a posterior long arm splint.

  1. Traumatic atlantooccipital dislocation.

    Science.gov (United States)

    Van den Bout, A H; Dommisse, G F

    1986-03-01

    A young adult sustained a traumatic atlantooccipital dislocation together with fracture-dislocation at C.4/5 level and had total neurologic deficit below C4 segment. He retained full consciousness but required respiratory support. He developed a stress ulcer with hemorrhage and evidence of "shock lung." He responded to intensive care. Surgery on the 11th day secured reduction and internal fixation at both levels. Death due to respiratory and cardiac arrest followed on the 14th day. Postmortem examination revealed edema of the brain and brainstem.

  2. INCIDENTAL VOCABULARY LEARNING THROUGH READING

    OpenAIRE

    Holly Warzecha, M.A. TESOL

    2017-01-01

    The purpose of the following paper is to take a closer look at the benefits of incidental learning through reading, with a specific focus on vocabulary acquisition. The teaching of vocabulary has traditionally been an explicit process where the target vocabulary is taken out of context and taught separately. However, this kind of explicit teaching and learning may only take into account a form-meaning connection. Therefore, this paper explores research on incidental learning and specifically ...

  3. Finite strain discrete dislocation plasticity

    NARCIS (Netherlands)

    Deshpande, VS; Needleman, A; Van der Giessen, E

    2003-01-01

    A framework for carrying out finite deformation discrete dislocation plasticity calculations is presented. The discrete dislocations are presumed to be adequately represented by the singular linear elastic fields so that the large deformations near dislocation cores are not modeled. The finite

  4. Medial subtalar dislocation

    African Journals Online (AJOL)

    Pr KODO

    A 27- year old female patient suffered from a closed medial subtalar dislocation treated by ... injury. She presented with pain, swelling of and internal rotation of the foot in relation to the knee joint. The talus was prominent dorsolaterally. Globally the clinical appearance was that ... frequently than the lateral ones and can be.

  5. Dislocated Worker Project.

    Science.gov (United States)

    1988

    Due to the severe economic decline in the automobile manufacturing industry in southeastern Michigan, a Dislocated Workers Program has been developed through the partnership of the Flint Area Chamber of Commerce, three community colleges, the National Center for Research in Vocational Education, the Michigan State Department of Education, the…

  6. Smectic meniscus and dislocations

    International Nuclear Information System (INIS)

    Geminard, J.C.; Oswald, P.; Holyst, R.

    1998-01-01

    In ordinary liquids the size of a meniscus and its shape is set by a competition between surface tension and gravity. The thermodynamical process of its creation can be reversible. On the contrary, in smectic liquid crystals the formation of the meniscus is always an irreversible thermodynamic process since it involves the creation of dislocations (therefore it involves friction). Also the meniscus is usually small in experiments with smectics in comparison to the capillary length and therefore the gravity does not play any role in determining the meniscus shape. Here we discuss the relation between dislocations and meniscus in smectics. The theoretical predictions are supported by a recent experiment performed on freely suspended films of smectic liquid crystals. In this experiment the measurement of the meniscus radius of curvature gives the pressure difference, Δp, according to the Laplace law. From the measurements of the growth dynamics of a dislocation loop (governed by Δp) we find the line tension (∼8 x 10 -8 dyn) and the mobility of an elementary edge dislocation (∼4 x 10 - 7 cm 2 s/g). (author)

  7. Grain boundaries in Ni3Al. 2

    International Nuclear Information System (INIS)

    Kung, H.; Sass, S.L.

    1992-01-01

    This paper discusses the dislocation structure of small angle tilt and twist boundaries in ordered Ni 3 Al, with and without boron, investigated using transmission electron microscopy. Dislocation with Burgers vectors that correspond to anti-phase boundary (APB)-coupled superpartials were found in small angle twist boundaries in both boron-free and boron-doped Ni 3 Al, and a small angle tilt boundary in boron-doped Ni 3 Al. The boundary structures are in agreement with theoretical models proposed by Marcinkowski and co-workers. The APB energy determined from the dissociation of the grain boundary dislocations was lower than values reported for isolated APBs in Ni 3 Al. For small angle twist boundaries the presence of boron reduced the APB energy at the interface until it approached zero. This is consistent with the structure of these boundaries containing small regions of increased compositional disorder in the first atomic plane next to the interface

  8. Nucleation of small angle boundaries

    CSIR Research Space (South Africa)

    Nabarro, FRN

    1996-12-01

    Full Text Available The internal stresses induced by the strain gradients in an array of lattice cells delineated by low-angle dislocation boundaries are partially relieved by the creation of new low-angle boundaries. This is shown to be a first-order transition...

  9. Dechanneling by dislocation loops

    International Nuclear Information System (INIS)

    Chalant, Gerard.

    1976-09-01

    Ion implantation always induces the creation of dislocation loops. When the damage profile is determined by a backscattering technique, the dechanneling by these loops is implicitely at the origin of these measurements. The dechanneling of alpha particles by dislocation loops produced by the coalescence of quenched-in vacancies in aluminium is studied. The dechanneling and the concentration of loops were determined simultaneously. The dechanneling width around dislocation was found equal to lambda=6A, both for perfect and imperfect loops having a mean diameter d=250A. In the latter case, a dechanneling probability chi=0.34 was determined for the stacking fault, in good agreement with previous determination in gold. A general formula is proposed which takes into account the variation of lambda with the curvature (or the diameter d) of the loops. Finally, by a series of isothermal anneals, the self-diffusion energy ΔH of aluminium was measured. The value obtained ΔH=1.32+-0.10eV is in good agreement with the values obtained by other methods [fr

  10. Mobilities and dislocation energies of planar faults in an ordered ...

    Indian Academy of Sciences (India)

    Present work describes the stability of possible planar faults of the A3B (D019) phase with an axial ratio less than the ideal. Mobilities and dislocation energies of various planar faults viz. antiphase boundaries (APBs), superlattice intrinsic stacking faults (SISFs) and complex stacking faults (CSFs) have been computed using ...

  11. 25 CFR 700.199 - Incidental expenses.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Incidental expenses. 700.199 Section 700.199 Indians THE... Expenses § 700.199 Incidental expenses. (a) Eligible costs. Subject to the limitations in paragraphs (b) and (c) of this section, the incidental expenses to be paid are those actually incurred by the...

  12. A discrete dislocation dynamics model of creeping single crystals

    Science.gov (United States)

    Rajaguru, M.; Keralavarma, S. M.

    2018-04-01

    Failure by creep is a design limiting issue for metallic materials used in several high temperature applications. Current theoretical models of creep are phenomenological with little connection to the underlying microscopic mechanisms. In this paper, a bottom-up simulation framework based on the discrete dislocation dynamics method is presented for dislocation creep aided by the diffusion of vacancies, known to be the rate controlling mechanism at high temperature and stress levels. The time evolution of the creep strain and the dislocation microstructure in a periodic unit cell of a nominally infinite single crystal is simulated using the kinetic Monte Carlo method, together with approximate constitutive laws formulated for the rates of thermal activation of dislocations over local pinning obstacles. The deformation of the crystal due to dislocation glide between individual thermal activation events is simulated using a standard dislocation dynamics algorithm, extended to account for constant stress periodic boundary conditions. Steady state creep conditions are obtained in the simulations with the predicted creep rates as a function of stress and temperature in good agreement with experimentally reported values. Arrhenius scaling of the creep rates as a function of temperature and power-law scaling with the applied stress are also reproduced, with the values of the power-law exponents in the high stress regime in good agreement with experiments.

  13. Treating Proximal Interphalangeal Joint Dislocations.

    Science.gov (United States)

    Saitta, Bradley Hart; Wolf, Jennifer Moriatis

    2018-05-01

    Proximal interphalangeal (PIP) joint dislocation a common injury. Usually, concentric stable reduction can be achieved with closed reduction. Occasionally, PIP joint dislocations are irreducible and open reduction is necessary. Complications include prolonged splinting and delay in presentation with subluxation or persistent dislocation. Surgery is often recommended for contracture or joint reduction. Surgical techniques focus on contracture release, joint reduction, and range of motion. Techniques have evolved from primary repair to tenodesis and suture anchor reconstruction. Most studies on PIP joint dislocations are retrospective case reports with good outcomes but chronic mild contracture and deformity are consistent in the literature. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Green’s function molecular dynamics meets discrete dislocation plasticity

    Science.gov (United States)

    Venugopalan, Syam P.; Müser, Martin H.; Nicola, Lucia

    2017-09-01

    Metals deform plastically at the asperity level when brought in contact with a counter body even when the nominal contact pressure is small. Modeling the plasticity of solids with rough surfaces is challenging due to the multi-scale nature of surface roughness and the length-scale dependence of plasticity. While discrete-dislocation plasticity (DDP) simulations capture size-dependent plasticity by keeping track of the motion of individual dislocations, only simple two-dimensional surface geometries have so far been studied with DDP. The main computational bottleneck in contact problems modeled by DDP is the calculation of the dislocation image fields. We address this issue by combining two-dimensional DDP with Green’s function molecular dynamics. The resulting method allows for an efficient boundary-value-method based treatment of elasticity in the presence of dislocations. We demonstrate that our method captures plasticity quantitatively from single to many dislocations and that it scales more favorably with system size than conventional methods. We also derive the relevant Green’s functions for elastic slabs of finite width allowing arbitrary boundary conditions on top and bottom surface to be simulated.

  15. High temperature dislocation processes in precipitation hardened crystals investigated by a 3D discrete dislocation dynamics

    Czech Academy of Sciences Publication Activity Database

    Záležák, Tomáš; Svoboda, Jiří; Dlouhý, Antonín

    2017-01-01

    Roč. 97, OCT (2017), s. 1-23 ISSN 0749-6419 R&D Projects: GA ČR(CZ) GA14-22834S; GA ČR(CZ) GA202/09/2073; GA ČR(CZ) GD106/09/H035; GA MŠk(CZ) EE2.3.20.0214; GA MŠk OC 162 EU Projects: European Commission(XE) 309916 - Z-ULTRA Institutional support: RVO:68081723 Keywords : 3D discrete dislocation dynamics * Dislocations * Strengthening mechanisms * Low angle grain boundaries * Particulate reinforced material Subject RIV: JI - Composite Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 5.702, year: 2016

  16. Dislocation mediated alignment during metal nanoparticle coalescence

    International Nuclear Information System (INIS)

    Lange, A.P.; Samanta, A.; Majidi, H.; Mahajan, S.; Ging, J.; Olson, T.Y.; Benthem, K. van; Elhadj, S.

    2016-01-01

    Dislocation mediated alignment processes during gold nanoparticle coalescence were studied at low and high temperatures using molecular dynamics simulations and transmission electron microscopy. Particles underwent rigid body rotations immediately following attachment in both low temperature (500 K) simulated coalescence events and low temperature (∼315 K) transmission electron microscopy beam heating experiments. In many low temperature simulations, some degree of misorientation between particles remained after rigid body rotations, which was accommodated by grain boundary dislocation nodes. These dislocations were either sessile and remained at the interface for the duration of the simulation or dissociated and cross-slipped through the adjacent particles, leading to improved co-alignment. Minimal rigid body rotations were observed during or immediately following attachment in high temperature (1100 K) simulations, which is attributed to enhanced diffusion at the particles' interface. However, rotation was eventually induced by {111} slip on planes parallel to the neck groove. These deformation modes led to the formation of single and multi-fold twins whose structures depended on the initial orientation of the particles. The driving force for {111} slip is attributed to high surface stresses near the intersection of low energy {111} facets in the neck region. The details of this twinning process were examined in detail using simulated trajectories, and the results reveal possible mechanisms for the nucleation and propagation of Shockley partials on consecutive planes. Deformation twinning was also observed in-situ using transmission electron microscopy, which resulted in the co-alignment of a set of the particles' {111} planes across their grain boundary and an increase in their dihedral angle. This constitutes the first detailed experimental observation of deformation twinning during nanoparticle coalescence, validating simulation results

  17. Nature of Dislocations in Silicon

    DEFF Research Database (Denmark)

    Hansen, Lars Bruno; Stokbro, Kurt; Lundqvist, Bengt

    1995-01-01

    Interaction between two partial 90 degrees edge dislocations is studied with atomic-scale simulations using the effective-medium tight-binding method. A large separation between the two dislocations (up to 30 Angstrom), comparable to experimental values, is achieved with a solution of the tight...

  18. Traumatic atlantooccipital dislocation. Case report.

    Science.gov (United States)

    Fruin, A H; Pirotte, T P

    1977-05-01

    A case of traumatic atlantooccipital dislocation is presented and the literature reviewed. This type of traumatic dislocation is probably produced by violent hyperextension of the upper cervical spine. Cranial nerve injuries and spinal cord injuries are common. Early fusion is recommended.

  19. Traumatic hip dislocations in children

    International Nuclear Information System (INIS)

    Minhas, M.S.

    2010-01-01

    Objectives: To evaluate clinical features, treatment and relationship to the time period between dislocation, reduction and early complications of traumatic dislocation of hip in children. Methods: Case series conducted at Jinnah Post Graduate Medical Centre Karachi from July 2005 to August 2009. Children with traumatic hip dislocation up to fifteen years of age who presented in last four years were included in this study. Their clinical information, etiology, associated injuries, duration, method of reduction and early complications are evaluated through emergency room proforma and indoor record. Follow up of patient was updated in outpatient department. Results: We had eight patients, six boys and two girls. Youngest 2.4 years and eldest was 12 years with mean age of 6.2 +- 3.8 years. All presented with posterior hip dislocation. Etiology was road traffic accident in two and history of fall in remaining six patients. Average duration of time between dislocation and reduction was 19 hours range 3-72 hours. Dislocated hips were reduced under General Anaesthesia in two patients and under sedation analgesia in six patients. No complications were noted in eight cases with mean 18.75 +- 13.23 months follows up. Conclusion: Traumatic hip dislocation in children is not rare. Slight trauma causes dislocation in younger age and immediate closed reduction and Immobilization reduces complications. (author

  20. Temporomandibular joint dislocation in Nairobi.

    Science.gov (United States)

    Sang, L K; Mulupi, E; Akama, M K; Muriithi, J M; Macigo, F G; Chindia, M L

    2010-01-01

    Despite the diverse conservative and surgical modalities for the management of temporomandibular joint (TMJ) dislocation and the controversy that surrounds them, very little has been done within the East-African setup in terms of highlighting and provoking greater interest in the epidemiology and management of TMJ dislocation. To audit the pattern of occurrence, demographics, aetiology and enumerate the treatment modalities of TMJ dislocation at the oral and maxillofacial surgery division (OMFS) of the University of Nairobi Dental Hospital. Descriptive cross-sectional study. University of Nairobi Dental Hospital (UNDH) from January 1995 to July 2005. Twenty nine patients had been diagnosed and managed for TMJ dislocation. Twenty (69%) were females and nine (31%) were males. Their ages ranged from 10-95 years with a mean of 42 years. The cases managed were primarily chronic in nature. The most common form being anterior TMJ dislocation, accounting for twenty-five (86.2%) cases. Trauma was implicated as an aetiology in only five (17%) of the cases while the remaining majority of twenty four (83%) cases were spontaneous. Amongst the causes of spontaneous TMJ dislocation, yawning was the most common accounting for fourteen cases (48.3%). Dislocations caused by trauma were found to be 12.6 times more likely to be associated with other injuries than spontaneous dislocations. Anterior TMJ dislocations were found to be 1.3 times more likely to be associated with absence of molars than posterior TMJ dislocations. Anatomical aberrations, as predisposing factors, were not a significant finding in this research. Eight (28%) of the cases were managed conservatively. Twenty one (72%) of the cases were managed surgically. The eminectomy was the most common technique with a 75% success rate. The highest incidence of TMJ dislocation occurs in the 3rd-5th decade with a female preponderance with bilateral anterior TMJ dislocation being the most common. Most of the cases were managed

  1. Strengthening mechanisms and dislocation processes in <111> textured nanotwinned copper

    International Nuclear Information System (INIS)

    Zhao, Xing; Lu, Cheng; Tieu, Anh Kiet; Pei, Linqing; Zhang, Liang; Cheng, Kuiyu; Huang, Minghui

    2016-01-01

    We use molecular dynamics simulations to elucidate the deformation mechanisms of <111> textured nanotwinned materials under tensile loading parallel to the twin boundary (TB). Our simulations reveal that the tensile strength of nanotwinned Cu increases monotonically as the twin spacing decreases. The strengthening effect mainly results from TB restricting the transmission of dislocations across the TB. Throughout the simulations the transmissions of dislocations across the TBs dominate the plastic deformation. Both direct and indirect transmissions are identified at atomic level. Direct transmission involves either successive transmission of the leading and trailing partials as in the Fleischer cross-slip model or absorption and desorption of the extended dislocation as in the Friedel-Escaig cross-slip mechanism. In contrast, indirect transmission involves the formation of special superjogs. The persistent slip transfer leaves zigzag slip traces on the cross-sectional view and the inhomogeneous deformation leads to the formation of intersecting slip bands on the plane view.

  2. INCIDENTAL VOCABULARY LEARNING THROUGH READING

    Directory of Open Access Journals (Sweden)

    Holly Warzecha, M.A. TESOL

    2017-04-01

    Full Text Available The purpose of the following paper is to take a closer look at the benefits of incidental learning through reading, with a specific focus on vocabulary acquisition. The teaching of vocabulary has traditionally been an explicit process where the target vocabulary is taken out of context and taught separately. However, this kind of explicit teaching and learning may only take into account a form-meaning connection. Therefore, this paper explores research on incidental learning and specifically looks at what it takes to acquire new vocabulary incidentally through reading while considering the coverage rates of texts, how many words must be known already from the text, how many repetitions it takes to learn a word, types of texts that promote learning, and the effects of pairing students‘ reading with learner tasks. After reviewing many studies, it can be concluded that more reading is better. More specifically, extensive reading of chosen novels at an appropriate level and interest to the students showed important gains in vocabulary. In addition, readings that were supplemented with additional activities that focused on both form and meaning showed an even higher increase in word retention.

  3. Reactions between a 1/2⟨111⟩ screw dislocation and ⟨100⟩ interstitial dislocation loops in alpha-iron modelled at atomic scale

    Science.gov (United States)

    Terentyev, D.; Bacon, D. J.; Osetsky, Yu. N.

    2010-03-01

    Interstitial dislocation loops with Burgers vector of ? type are observed in α-iron irradiated by neutrons or heavy ions, and their population increases with increasing temperature. Their effect on motion of a ? edge dislocation was reported earlier 1. Results are presented of a molecular dynamics study of interactions between a ? screw dislocation and ? loops in iron at temperature in the range 100 to 600 K. A variety of reaction mechanisms and outcomes are observed and classified in terms of the resulting dislocation configuration and the maximum stress required for the dislocation to break away. The highest obstacle resistance arises when the loop is absorbed to form a helical turn on the screw dislocation line, for the dislocation cannot glide away until the turn closes and a loop is released with the same Burgers vector as the line. Other than one situation found, in which no dislocation-loop reaction occurs, the weakest obstacle strength is found when the original ? loop is restored at the end of the reaction. The important role of the cross-slip and the influence of model boundary conditions are emphasised and demonstrated by examples.

  4. Asymptotic analysis of a pile-up of regular edge dislocation walls

    KAUST Repository

    Hall, Cameron L.

    2011-12-01

    The idealised problem of a pile-up of regular dislocation walls (that is, of planes each containing an infinite number of parallel, identical and equally spaced dislocations) was presented by Roy et al. [A. Roy, R.H.J. Peerlings, M.G.D. Geers, Y. Kasyanyuk, Materials Science and Engineering A 486 (2008) 653-661] as a prototype for understanding the importance of discrete dislocation interactions in dislocation-based plasticity models. They noted that analytic solutions for the dislocation wall density are available for a pile-up of regular screw dislocation walls, but that numerical methods seem to be necessary for investigating regular edge dislocation walls. In this paper, we use the techniques of discrete-to-continuum asymptotic analysis to obtain a detailed description of a pile-up of regular edge dislocation walls. To leading order, we find that the dislocation wall density is governed by a simple differential equation and that boundary layers are present at both ends of the pile-up. © 2011 Elsevier B.V.

  5. Knee Dislocations in Sports Injuries

    Science.gov (United States)

    Pardiwala, Dinshaw N; Rao, Nandan N; Anand, Karthik; Raut, Alhad

    2017-01-01

    Knee dislocations are devastating when they occur on the athletic field or secondary to motor sports. The complexity of presentation and spectrum of treatment options makes these injuries unique and extremely challenging to even the most experienced knee surgeons. An astute appreciation of the treatment algorithm is essential to plan individualized management since no two complex knee dislocations are ever the same. Moreover, attention to detail and finesse of surgical technique are required to obtain a good functional result and ensure return to play. Over the past 10 years, our service has treated 43 competitive sportsmen with knee dislocations, and this experience forms the basis for this narrative review. PMID:28966379

  6. Traumatic atlantooccipital dislocation with survival.

    Science.gov (United States)

    Woodring, J H; Selke, A C; Duff, D E

    1981-07-01

    Traumatic atlantooccipital dislocation is generally considered incompatible with life. However, there have been isolated survivals from this injury, and a few patients initially have minimal neurologic deficits disproportionate to the gravity of their injury, a feature that has not been adequately stressed. The potentially catastrophic results of delayed therapy make early radiographic detection imperative. Marked retropharyngeal soft-tissue swelling, an abnormal basion-odontoid alignment, and posterior displacement of the atlas are diagnostic of anterior atlantooccipital dislocation. In the more uncommon posterior atlantooccipital dislocation an abnormal basion-odontoid alignment associated with marked soft-tissue swelling should suggest the correct diagnosis. Conventional tomography can be confirmatory.

  7. 3D Discrete Dislocation Dynamics Applied to Interactions between Dislocation Walls and Particles

    Czech Academy of Sciences Publication Activity Database

    Záležák, Tomáš; Dlouhý, Antonín

    2012-01-01

    Roč. 122, č. 3 (2012), s. 450-452 ISSN 0587-4246. [International Symposium on Physics of Materials /12./ - ISPMA 12. Prague, 04.09.2011-08.09.2011] R&D Projects: GA ČR GD106/09/H035; GA ČR GA202/09/2073; GA MŠk OC 162 Institutional research plan: CEZ:AV0Z20410507 Keywords : 3D discrete dislocation dynamics * tilt boundary * migration * diffusion * pecipitation hardening Subject RIV: JG - Metallurgy Impact factor: 0.531, year: 2012

  8. 78 FR 33357 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2013-06-04

    ... confidence in these values is unknown. Table 3--Marine Mammal Density Estimates Density Species (animals/km\\2... unintentional taking of marine animals occurring incidental to the shock testing which involved large explosives... Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Conducting...

  9. Neglected locked vertical patellar dislocation

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Gupta

    2012-01-01

    Full Text Available Patellar dislocations occurring about the vertical and horizontal axis are rare and irreducible. The neglected patellar dislocation is still rarer. We describe the clinical presentation and management of a case of neglected vertical patellar dislocation in a 6 year-old boy who sustained an external rotational strain with a laterally directed force to his knee. Initially the diagnosis was missed and 2 months later open reduction was done. The increased tension generated by the rotation of the lateral extensor retinaculum kept the patella locked in the lateral gutter even with the knee in full extension. Traumatic patellar dislocation with rotation around a vertical axis has been described earlier, but no such neglected case has been reported to the best of our knowledge.

  10. Arthroscopic treatment of acromioclavicular dislocation

    OpenAIRE

    Mihai T. Gavrilă; Ștefan Cristea

    2017-01-01

    A thorough understanding of biomechanical function of both acromioclavicular (AC) and coracoclavicular (CC) ligaments, stimulated surgeons to repair high-grade AC dislocation using arthroscopic technique. This technique necessitates a clear understanding of shoulder anatomy, especially of the structures in proximity to the clavicle and coracoid process and experiences in arthroscopic surgery. The follow case describes an arthroscopic technique used to treat AC dislocation in young man 30 year...

  11. HRTEM studies of dislocations in cubic BN

    International Nuclear Information System (INIS)

    Nistor, L.C.; Tendeloo, G. van; Dinca, G.

    2004-01-01

    The atomic structure of dislocations in cubic boron nitride has been investigated by high resolution transmission electron microscopy. Most of the perfect dislocations, screw and 60 edge, are dissociated. A 60 dislocation which was undissociated has been analysed. Computer simulation is performed in an attempt to characterise the core structure. Twinning dislocations and dislocations resulting from the intersection of stacking faults are also revealed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. HRTEM studies of dislocations in cubic BN

    Energy Technology Data Exchange (ETDEWEB)

    Nistor, L.C. [National Institute for Materials Physics, P.O. Box MG-7 Magurele, 077125 Bucharest (Romania); Tendeloo, G. van [University of Antwerp, EMAT, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Dinca, G. [Dacia Synthetic Diamond Factory, Timisoara av. 5, P.O. Box 58-52, 077350 Bucharest (Romania)

    2004-09-01

    The atomic structure of dislocations in cubic boron nitride has been investigated by high resolution transmission electron microscopy. Most of the perfect dislocations, screw and 60 edge, are dissociated. A 60 dislocation which was undissociated has been analysed. Computer simulation is performed in an attempt to characterise the core structure. Twinning dislocations and dislocations resulting from the intersection of stacking faults are also revealed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Trans-triquetral Perilunate fracture dislocation

    OpenAIRE

    John-Henry Rhind; Abhinav Gulihar; Andrew Smith

    2018-01-01

    Perilunate dislocations and perilunate fracture dislocations are rare and serious injuries. Perilunate dislocations represent less than 10% of all carpal injuries of which 61% represent transcaphoid fractures. Because of their rarity, up to 25% of perilunate dislocations are initially missed on first assessment. We present the case of a 66-year-old-gentleman who sustained an isolated trans-triquetral perilunate fracture dislocation while walking his dog. This was diagnosed in the emergency de...

  14. Perilunar carpal dislocations treatment outcome.

    Science.gov (United States)

    Gagała, Jacek; Tarczyńska, Marta; Kosior, Piotr

    2006-06-30

    Background. The aim of the study was to analyze late outcomes of perilunar carpal dislocations, depending on the type of the injury, time of the diagnosis and the treatment methods. Material and methods. The material is constituted by 37 patients treated in our department between 1981-2004 because of perilunar dislocation. In group were 2 women and 35 men, aged 19-56 (mean 31 years). All patients were asked for control visit. DASH and Mayo score were used to evaluate the outcome. Range of wrist motion, its stability, grip strength and X-ray pictures were analyzed. Results. Better follow-up results were observed in persons with early diagnosed dislocations of the wrist. The best outcomes were observed in group with perilunar early diagnosed dislocations, which were treated by open reduction. Posttraumatic wrist instability often was diagnosed in patients with dislocation of lunar bone and late-diagnosed transscaphoid perilunar carpal dislocations. Conclusions. The data we obtained show, that the consequences of late-diagnosed and late-treated injuries of the wrist are instability, pain, decrease in range of motion and hand skills.

  15. In situ TEM observations of reverse dislocation motion upon unloading in tensile-deformed UFG aluminium

    International Nuclear Information System (INIS)

    Mompiou, Frédéric; Caillard, Daniel; Legros, Marc; Mughrabi, Haël

    2012-01-01

    Loading–unloading cycles have been performed on ultrafine-grained (UFG) aluminium inside a transmission electron microscope (TEM). The interaction of dislocations with grain boundaries, which is supposed to be at the origin of the inelastic behaviour of this class of materials, differs according to the main character of the dislocation segments involved in pile-ups. Pile-ups are formed by spiral sources and lead to the incorporation of dislocations into grain boundaries (GBs) during loading. Upon unloading, partial re-emission of dislocations from GBs can be observed. Stress and strain measurements performed during these in situ TEM loading–unloading experiments are in agreement with the rather large inelastic reverse strains observed during unloading in loading–unloading tests on bulk macroscopic UFG aluminium specimens.

  16. Autosomal Dominant Polycystic Kidney Disease, incidental finding ...

    African Journals Online (AJOL)

    Introduction: Pre-existing renal lesions predispose kidneys to effects of otherwise insignificant blunt trauma, and may uncommonly present as an incidental finding in the workup of a suspected renal injury. Observation: This is a case report of a 28-year-old male diagnosed incidentally with Autosomal Dominant Polycystic ...

  17. Dependence of dislocation structure on orientation and slip systems in highly oriented nanotwinned Cu

    DEFF Research Database (Denmark)

    Lu, Qiuhong; You, Zesheng; Huang, Xiaoxu

    2017-01-01

    To explore the correlation between orientation, active slip systems and dislocation structure, highly oriented nanotwinned Cu has been deformed in compression to 2% and 6% strain. The compression directions are 90°, 0° and 45° with respect to the twin boundaries (TBs) of the almost parallel twins...... parallel to the twin plane. The analysis of the dislocation structures illustrate the strong correlation between active slip systems and the dislocation structure and the strong effect of slip mode anisotropy on both the flow stress and strain hardening rate of nanotwinned Cu....

  18. Stress field of a dislocating inclined fault

    Energy Technology Data Exchange (ETDEWEB)

    Huang, F.; Wang, T.

    1980-02-01

    Analytical expressions are derived for the stress field caused by a rectangular dislocating fault of an arbitrary dip in a semi-infinite elastic medium for the case of unequal Lame constants. The results of computations for the stress fields on the ground surface of an inclined strike-slip and an inclined dip-slip fault are represented by contour maps. The effects of Poisson Ratio of the medium, the dip angle, upper and lower boundaries of the faults on the stress field at surface have been discussed. As an application, the contour maps for shear stress and hydrostatic stress of near fields of the Tonghai (1970), Haicheng (1975) and Tangshan (1976) earthquakes have been calculated and compared with the spatial distributions of strong aftershocks of these earthquakes. It is found that most of the strong aftershocks are distributed in the regions of tensional stress, where the hydrostatic stress is positive.

  19. Stress field of a dislocating inclined fault

    Energy Technology Data Exchange (ETDEWEB)

    Huang, F.; Wang, T.

    1980-02-01

    In this paper, analytical expressions of the stress field given rise by a rectangular dislocating fault of an arbitrary dip in a semi-infinite elastic medium for the case of unequal Lame constants are derived. The results of computations for the stress fields on the ground surface of an inclined strike-slip and an inclined dip-slip fault are represented by contour maps. The effects of the Poisson Ratio of the medium, the dip angle, upper and lower boundaries of the faults on the stress field at the surface have been discussed. As an application, the contour maps for shear stress and hydrostatic stress of near fields of the Tonghai (1970), Haicheng, (1975) and Tangshan (1976) earthquakes have been calculated and compared with the spatial distributions of strong aftershocks of these earthquakes. It is found that most of the strong aftershocks are distributed in the regions of tensional stress where the hydrostatic stress is positive.

  20. Incidental versus non-incidental thyroid carcinoma: Clinical presentation, surgical management and prognosis.

    Science.gov (United States)

    González-Sánchez-Migallón, Elena; Flores-Pastor, Benito; Pérez-Guarinos, Carmen Victoria; Miguel-Perelló, Joana; Chaves-Benito, Asunción; Illán-Gómez, Fátima; Carrillo-Alcaraz, Andrés; Aguayo-Albasini, José Luis

    2016-11-01

    Thyroid cancer may be clinically evident as a tumor mass in the neck or as a histopathological incidental finding after thyroid surgery for an apparent benign condition. Our objective was to assess the differences in clinical signs, surgical management, and course between incidental and clinically diagnosed thyroid tumors. A retrospective study was conducted on patients operated on for benign or malignant thyroid disease from January 2000 to March 2014. Among the 1415 patients who underwent any thyroid surgery, 264 neoplasms were found, of which 170 were incidental. A comparison was made of incidental versus non-incidental carcinomas. Among incidental carcinomas, cases whose indication for surgery was Graves' disease were compared to those with multinodular goiter. Incidental carcinomas were in earlier stages and required less aggressive surgery. There were no differences in surgical complications between incidental and clinical tumors, but mortality and relapses were markedly higher in non-incidental cancers (4.4% vs 0% and 13.2% vs 4.8% respectively). Carcinomas developing on Graves' disease showed no differences from all other incidental tumors in terms of complications, mortality, or relapse after surgery. Early stage thyroid cancer has better survival and prognosis after surgical treatment. Copyright © 2016 SEEN. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Irreducible Galeazzi Fracture-Dislocations.

    Science.gov (United States)

    Yohe, Nicholas J; De Tolla, Jadie; Kaye, Marc B; Edelstein, David M; Choueka, Jack

    2017-11-01

    Fractures of the radial shaft with disruption of the distal radial ulnar joint (DRUJ) or Galeazzi fractures are treated with reduction of the radius followed by stability assessment of the DRUJ. In rare instances, the reduction of the DRUJ is blocked by interposed structures requiring open reduction of this joint. The purpose of this study is to review all cases of irreducible Galeazzi fracture-dislocations reported in the literature to offer guidelines in the diagnosis and management of this rare injury. A search of the MEDLINE database, OVID database, and PubMed database was employed using the terms "Galeazzi" and "fracture." Of the 124 articles the search produced, a total of 12 articles and 17 cases of irreducible Galeazzi fracture-dislocations were found. The age range was 16 to 64 years (mean = 25 years). A high-energy mechanism of injury was the root cause in all cases. More than half of the irreducible DRUJ dislocations were not identified intraoperatively. In a dorsally dislocated DRUJ, a block to reduction in most cases (92.3%) was secondary to entrapment of one or more extensor tendons including the extensor carpi ulnaris, extensor digiti minimi, and extensor digitorum communis, with the remaining cases blocked by fracture fragments. Irreducible volar dislocations due to entrapment of the ulnar head occurred in 17.6% of cases with no tendon entrapment noted. In the presence of a Galeazzi fracture, a reduced/stable DRUJ needs to be critically assessed as more than half of irreducible DRUJs in a Galeazzi fracture-dislocation were missed either pre- or intraoperatively.

  2. Anterior shoulder dislocations in sports.

    Science.gov (United States)

    Aronen, J G

    1986-01-01

    Anterior shoulder dislocations, primary and recurrent, are among the most disabling injuries to the shoulder that can plague the athlete. The diagnosis is easily made by the following: the physical appearance of the shoulder; loss of capability by the athlete to internally and externally rotate the shoulder with the elbow at his side; by evaluating the mechanism of injury; and x-rays. Anterior shoulder dislocations should be reduced as soon as possible after diagnosis, to minimise the stretching effect on the neurovascular structures while the humeral head is dislocated. The reduction is not done to allow the athlete to return immediately to sport. Use of a simple traction method in the first 10 to 15 minutes following the injury will result in a successful reduction in the vast majority of dislocations. Reduction of the humeral head can be confirmed by the athlete regaining the capability to internally and externally rotate his shoulder with his elbow at his side. Following reduction, the athlete should begin a treatment regimen which includes a restrengthening programme emphasising the muscles of internal rotation and adduction plus rigid restrictions of activities until the goals of the rehabilitation programme are satisfied. The author's experience with this treatment regimen with athletes at the United States Naval Academy, has shown a decrease of the recurrence rate of primary anterior shoulder dislocations to 25% versus the 80% recurrence rate we have become familiar with from studies done which did not stress specific rehabilitation programmes. The athlete should also be instructed in a self-performed traction method for reduction should a redislocation occur, to minimise the stretching effect on the neurovascular structures and allow relief from discomfort. Surgery for primary and recurrent anterior dislocations should only be considered when the athlete fails to achieve the desired goals after participating in a specific, progressive, adequate

  3. Renal Myxoma, an Incidental Finding

    Directory of Open Access Journals (Sweden)

    Parth Thakker

    2017-07-01

    Full Text Available Myxomas are mesenchymal tumors commonly found in the heart and skin. Renal myxomas are rare, having only been documented 14 times. Our case is a 55-year-old woman who presented to our clinic after a right renal mass was incidentally found on CT. Evaluation with MRI showed a mass that appeared to arise from the supero-medial cortex of the right kidney. As the imaging was concerning for renal cell carcinoma, the patient underwent a partial nephrectomy. Microscopic examination showed a well-circumscribed mass with polygonal to spindle-shaped cells in a granular eosinophilic cytoplasm. Immunohistochemical staining for CD-10, Desmin, HMB-45, and Pankeratin were negative.

  4. Irreducible Traumatic Posterior Shoulder Dislocation

    Directory of Open Access Journals (Sweden)

    Blake Collier

    2017-01-01

    Full Text Available History of present illness: A 22-year-old male presented to the Emergency Department complaining of right shoulder pain after a motocross accident. He was traveling at approximately 10 mph around a turn when he lost control and was thrown over the handlebars, landing directly on his right shoulder. On arrival, he was holding his arm in adduction and internal rotation. An area of swelling was noted over his anterior shoulder. He was unable to abduct his shoulder. No humeral gapping was noted. He had normal neuro-vascular status distal to the injury. Significant findings: Radiographs demonstrated posterior displacement of the humeral head on the “Y” view (see white arrow and widening of the glenohumeral joint space on anterior-posterior view (see red arrow. The findings were consistent with posterior dislocation and a Hill-Sachs type deformity. Sedation was performed and reduction was attempted using external rotation, traction counter-traction. An immediate “pop” was felt during the procedure. Post-procedure radiographs revealed a persistent posterior subluxation with interlocking at posterior glenoid. CT revealed posterior dislocation with acute depressed impaction deformity medial to the biceps groove with the humeral head perched on the posterior glenoid, interlocked at reverse Hill-Sachs deformity (see blue arrow. Discussion: Posterior shoulder dislocations are rare and represent only 2% of all shoulder dislocations. Posterior shoulder dislocations are missed on initial diagnosis in more than 60% of cases.1 Posterior shoulder dislocations result from axial loading of the adducted and internally rotated shoulder, violent muscle contractions (resulting from seizures or electrocution, a direct posterior force applied to the anterior shoulder.1 Physical findings include decreased anterior prominence of the humeral head, increased palpable posterior prominence of the humeral head below the acromion, increased palpable prominence of the

  5. The Trapping of Helium at a Low Angle Tilt Boundary in Molybdenum

    NARCIS (Netherlands)

    Evans, J.H.; Veen, A. van; Hosson, J.Th.M. De; Bullough, R.; Willis, J.R.

    1984-01-01

    This paper presents experimental evidence of helium trapping at a set of b = [100] edge dislocations defining a low angle tilt boundary in molybdenum together with theoretical results on two aspects of helium-dislocation behaviour. The low angle boundary, with a misfit angle of ≈1/5 °, was found

  6. Long-range stresses associated with boundaries in deformed materials

    DEFF Research Database (Denmark)

    Leffers, T.

    1995-01-01

    The deviation from a perfect low energy dislocation structure (LEDS) for the boundaries in deformed polycrystals is described. For polycrystals with approximately equiaxed grains it is argued that the existence of the grain boundaries introduces a population of geometrically necessary dislocations...... around the boundaries, a population which, because of the long-range stresses associated, does not represent a perfect LEDS, but the deviation is moderate. For polycrystals with flat grains and for polycrystals with the grains subdivided into flat bands the geometrically necessary dislocations may remain...... in the (grain or band) boundaries, but they still represent a certain, moderate deviation from LEDS. A distinction is made between two contributions from the geometrically necessary dislocations to hardening: conservative hardening which is associated with long-range stresses and frictional hardening which...

  7. Atomistic simulations of dislocation processes in copper

    DEFF Research Database (Denmark)

    Vegge, T.; Jacobsen, K.W.

    2002-01-01

    We discuss atomistic simulations of dislocation processes in copper based on effective medium theory interatomic potentials. Results on screw dislocation structures and processes are reviewed with particular focus on point defect mobilities and processes involving cross slip. For example, the sta......We discuss atomistic simulations of dislocation processes in copper based on effective medium theory interatomic potentials. Results on screw dislocation structures and processes are reviewed with particular focus on point defect mobilities and processes involving cross slip. For example...

  8. Atlantooccipital dislocation: a case report.

    Science.gov (United States)

    Williams, M J; Elliott, J L; Nichols, J

    1995-03-01

    We report on a child who suffered an atlantooccipital dislocation and survived. The patient required tracheostomy and feeding gastrostomy due to retropharyngeal swelling from a traumatic pseudomeningocele. He later underwent fusion of his occiput to C3. The complications of such an injury and the anesthetic management are discussed.

  9. Lateral atlantooccipital dislocation: case report.

    Science.gov (United States)

    Watridge, C B; Orrison, W W; Arnold, H; Woods, G A

    1985-08-01

    A case of lateral atlantooccipital dislocation is presented, and its successful management is outlined, demonstrating the importance of the physical examination and the utilization of computed tomography. Open reduction and stabilization with direct visualization of the spinal axis is the preferred method of treatment.

  10. Medial peritalar fracture dislocation of the talar body

    Directory of Open Access Journals (Sweden)

    Jacob B. Stirton

    2015-04-01

    Full Text Available Peritalar fracture dislocations typically involve the talar neck and are classified according to Hawkins. To our knowledge, peritalar fracture dislocation involving the talar body has not been formally reported. In this article, we describe a case of peritalar fracture dislocation of the talar body. Keywords: Peritalar dislocation, Talus fracture, Talar body fracture dislocation, Medial subtalar dislocation

  11. Diffusion mechanisms in grain boundaries in solids

    International Nuclear Information System (INIS)

    Peterson, N.L.

    1982-01-01

    A critical review is given of our current knowledge of grain-boundary diffusion in solids. A pipe mechanism of diffusion based on the well-established dislocation model seems most appropriate for small-angle boundaries. Open channels, which have atomic configurations somewhat like dislocation cores, probably play a major role in large-angle grain-boundary diffusion. Dissociated dislocations and stacking faults are not efficient paths for grain-boundary diffusion. The diffusion and computer modeling experiments are consistent with a vacancy mechanism of diffusion by a rather well-localized vacancy. The effective width of a boundary for grain-boundary diffusion is about two atomic planes. These general features of grain-boundary diffusion, deduced primarily from experiments on metals, are thought to be equally applicable for pure ceramic solids. The ionic character of many ceramic oxides may cause some differences in grain-boundary structure from that observed in metals, resulting in changes in grain-boundary diffusion behavior. 72 references, 5 figures

  12. In situ TEM observation of dislocation motion in thermally strained Al nanowires

    International Nuclear Information System (INIS)

    Inkson, B.J.; Dehm, G.; Wagner, T.

    2002-01-01

    Al thin films deposited epitaxially on (0001) α-Al 2 O 3 substrates, have been thinned cross-sectionally to form Al nanowires. The Al wires, consisting of two Σ3 twin variants, have been strained in situ by differential thermal expansion between the Al wires and the Al 2 O 3 substrate during transmission electron microscopy heating. Dynamical observations show that maximum dislocation activity occurs in the first heating cycle up to 400 deg. C, with decreasing activity during further cycles. The {111} Al parallel (0001) α-Al 2 O 3 interface acts as a source of dislocation half-loops. The motion of threading dislocations along the wires generates long trailing dislocation segments parallel to, and offset from, the {111} Al parallel (0001) α-Al 2 O 3 interface. Dislocation multiplication occurs by the reaction of half-loops and extended threading dislocation segments at the wire boundaries and substrate interface. The Σ3 twin grains bisecting the wires are observed to be stable during thermal cycling to 400 deg. C, and their {211-bar} boundaries are weak pinning sites

  13. Incidental papillary fibroelastoma of the tricuspid valve

    OpenAIRE

    Strecker, Thomas; Scheuermann, Sabine; Nooh, Ehab; Weyand, Michael; Agaimy, Abbas

    2014-01-01

    Primary cardiac tumors are very rare, papillary fibroelastoma (PFE) being the second most common benign tumor of the heart in previous series. However, as a consequence of increased imaging examinations, incidental PFE may represent the most common cardiac tumor. Their clinical presentation varies from incidental asymptomatic masses to severe life-threatening cardiovascular complications necessitating emergency surgery. Here we report the diagnostic evaluation and successful surgical resectio...

  14. Medial subtalar dislocation: Case report

    Directory of Open Access Journals (Sweden)

    Manojlović Radovan

    2010-01-01

    Full Text Available Introduction. Subtalar dislocation (SI is a term that refers to an injury in which there is dislocation of the talonavicular and talocalcanear joint, although the tibiotalar joint is intact. Case Outline. A case of medial subtalar dislocation as a result of basketball injury, so-called 'basketball foot', is presented. Closed reposition in i.v. anaesthesia was performed with the patient in supine position and a knee flexed at 90 degrees. Longitudinal manual traction in line of deformity was carried out in plantar flexion. The reposition continued with abduction and eversion simultaneously increasing dorsiflexion. It was made in the first attempt and completed instantly. Rehabilitation was initiated after 5 weeks of immobilization. One year after the injury, the functional outcome was excellent with full range of motion and the patient was symptom-free. For better interpretation of roentgenogram, bone model of subtalar dislocation was made using the cadaver bone. Conclusion. Although the treatment of such injury is usually successful, diagnosis can be difficult because it is a rare injury, and moreover, X-ray of the injury can be confusing due to superposition of bones. Radiograms revealed superposition of the calcaneus, tarsal and metatarsal bones which was radiographically visualized in the anterior-posterior projection as one osseous block inward from the talus, and on the lateral view as in an osteal block below the tibial bone. Prompt recognition of these injuries followed by proper, delicately closed reduction under anaesthesia is crucial for achieving a good functional result in case of medial subtalar dislocation.

  15. Fetal MRI: incidental findings in the mother

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Selwan B. [University of Maryland Medical Center, Diagnostic Radiology and Nuclear Medicine, Baltimore, MD (United States); University of Minnesota, Medical School, Minneapolis, MN (United States); Dietz, Kelly R.; Holm, Tara L. [University of Minnesota, Department of Radiology, Minneapolis, MN (United States)

    2016-11-15

    Fetal magnetic resonance imaging (MRI) is a routinely used tool in prenatal diagnosis; however, there is a lack of studies evaluating incidental findings observed in the mother. This study describes and quantifies incidental findings observed in the mother during fetal MRI. We reviewed all fetal MRI studies at the University of Minnesota Medical Center from February 2008 to September 2014. Two pediatric radiologists retrospectively conducted a consensus evaluation. The maternal findings were categorized into neurologic, gynecologic, urinary, gastrointestinal and musculoskeletal. Hydronephrosis consistent with the stage of pregnancy was recorded but was not included as an abnormal finding. Abnormal findings were classified into three groups, depending on their clinical significance: level I (low), level II (medium) and level III (high). We evaluated 332 pregnant patients with a mean age of 29.3 years and a mean gestational age of 29 weeks. Of these, 55.4% had at least 1 incidental finding, for a total of 262 incidental maternal findings. Of the 262 abnormalities, 113 (43.1%) were neurologic, 69 were gynecologic (26.3%), 36 (13.7%) urinary, 24 (9.2%) gastrointestinal and 20 (7.6%) musculoskeletal. Of the 262 incidental findings, 237 (90.5%) were level I, 24 (9.2%) were level II and 1 (0.4%) was level III. Our results suggest that although the vast majority of incidental maternal findings are benign, more significant findings are still encountered and should be expected. (orig.)

  16. Posterior sternoclavicular dislocation: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, So Hwa; Kim, Ki Sun; Kim, Ki Jun [Dept. of Radiology, Incheon St. Mary' s Hospital, The Catholic University of Korea College of Medicine, Incheon (Korea, Republic of)

    2015-02-15

    Traumatic sternoclavicular joint dislocation is an uncommon injury, and posterior sternoclavicular dislocation occurs less frequently compared to anterior sternoclavicular dislocation. However, this type of dislocation has the potential for serious complications due to compression or laceration of the mediastinal structures. The diagnosis can be difficult using plain radiographs alone due to radiographic-anatomic superimposition. Therefore, posterior sternoclavicular dislocation is easily missed at the initial clinical evaluation. Contrast-enhanced computed tomography is required for a definite diagnosis and to assess associated mediastinal injuries.

  17. Acute, recurrent total knee dislocation: Polyethylene dislocation and malreduction

    Directory of Open Access Journals (Sweden)

    Samuel F. Thompson, BS

    2015-03-01

    Full Text Available A 62-year-old man underwent total knee arthroplasty using a mobile-bearing prosthesis. Four days post-operatively the patient experienced the first of several acute knee dislocations. Closed reduction was performed at an outside hospital a total of three times prior to presentation at this institution. A two-stage exchange of the TKA was recommended due to the clinical suspicion for an infected prosthesis. Upon surgical exploration, it was discovered that the polyethylene insert had spun out completely to 180°. Closed reduction attempts of a posterior dislocation of a mobile-bearing knee prosthesis may contribute to complete 180° spinout of the polyethylene insert.

  18. Incidental gallbladder cancer: what management?

    Directory of Open Access Journals (Sweden)

    Sidi Mohammed Bouchentouf

    2011-11-01

    Full Text Available Gallbladder cancer (GBC represents 3.8% of all gastrointestinal cancers and usually known to be of a poor prognosis. In 0.2–2.9% of cases, this cancer is found in cholecystectomy specimens. A better understanding of spread mode of this tumor helps a better surgical management. The aim of the present review is to underline the management of GBC based on the comprehension of risk factors and anatomic features. A Medline, PubMed database search was performed to identify articles published from 2000 to 2011 using the keywords ‘carcinoma of gallbladder’, ‘incidental gallbladder cancer’, ‘gallbladder neoplasm’ and ‘cholecystectomy’. Some pathological situations such as chronic lithiasis and biliopancreatic junction abnormalities have been clearly identified as predisposing to GBC. Laparoscopy increases peritoneal and parietal tumor dissemination, thus, it should not be performed when GBC is suspected. Most determinant prognostic factors are nodal, perineural and venous involvement, invasion of the cystic duct and the tumor differentiation. The simple cholecystectomy is sufficient for tumors classified as T1a; for other cancers exceeding the muscularis, radical re-resection is required due to the high risk of recurrence. This aggressive surgery improved the overall survival of patients. There is still no standard adjuvant treatment; patients should be included in prospective trials.

  19. Dislocation motion in tungsten: Atomistic input to discrete dislocation simulations

    Czech Academy of Sciences Publication Activity Database

    Srivastava, K.; Gröger, Roman; Weygand, D.; Gumbsch, P.

    2013-01-01

    Roč. 47, AUG (2013), s. 126-142 ISSN 0749-6419 R&D Projects: GA ČR GAP204/10/0255; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : body -centered cubic * non-Schmid effects * anomalous slip * discrete dislocation dynamics Subject RIV: BM - Solid Matter Physics ; Magnetism; BM - Solid Matter Physics ; Magnetism (UFM-A) Impact factor: 5.971, year: 2013

  20. Direct characterization of boron segregation at random and twin grain boundaries*

    International Nuclear Information System (INIS)

    Li Xiang-Long; Wu Ping; Yang Rui-Jie; Zhang Shi-Ping; Chen Sen; Wang Xue-Min; Huai Xiu-Lan

    2017-01-01

    Boron distribution at grain boundaries in hot-deformed nickel is directly characterized by the time-of-flight secondary ion mass spectrometry. The segregations of boron are observed at both the random and twin grain boundaries. Two types of segregations at random grain boundaries are observed. The first type of segregation has a high intensity and small width. Its formation is attributed to the incorporating of dislocations into the moving grain boundaries. The second type of segregation arises from the cooling induced segregation at the dislocations associated with the grain boundaries. The segregation at twin boundary is similar to the second type of segregation at random grain boundaries. (paper)

  1. Effect of Dislocation Mechanisms during Extrusion of Nanostructured Aluminum Powder Alloy

    Science.gov (United States)

    Jorge, A. M.; Peres, M. M.; Kiminami, C. S.; Bolfarini, C.; Botta, W. J.

    2009-12-01

    Nanostructured Al-3.0Fe-0.42Cu-0.37Mn powder alloy was deformed by extrusion over a temperature range of 375 °C to 425 °C, a ram speed range of 1 to 30 mm/s, and an extrusion rate of 10:1. Flow stresses and strain rates were calculated from the experimental ram pressures and speeds. The stress-strain-rate-temperature relationship in the extrusion of the nanostructured alloy was found to be similar to that in hot-worked conventional materials. The extrusion, torsion, compression, and creep data of nanostructured and conventional materials, extending over ten orders of magnitude of strain rate and over two orders of magnitude of stress, were correlated by a hyperbolic-sine constitutive equation, because the power and exponential laws lose linearity at high and low stresses, respectively. The hyperbolic-sine equation is widely used to correlate the hot-working behavior of conventional materials. It was concluded that the hot working of nanostructured powders is a thermally activated process in which the rate-controlling mechanism is the climb of edge dislocations. Microstructural changes in the consolidated alloys as a function of the extrusion conditions were investigated. An analysis was made of the dislocation behavior in very small grains of nanostructured metal by transmission electron microscopy (TEM) and we identified a dislocation structure and the different ways it appears in 40- to 100-nm Al-alloy grains. We also discuss the thermally activated propagation of dislocations and their interactions with shear bands/grain boundaries (SBs/GBs), and dislocation loops. Microstructural features including low-angle GBs, high-angle GBs, and equilibrium GBs and subgrain boundaries were observed. Dislocation structures under a deformation condition were studied to investigate the microstructural evolutions, which revealed some unique microstructural features such as dislocation tangle zones (DTZs) and dense-dislocation walls (DDWs), and the recovery process is

  2. The effect of grain boundary chemistry on the slip transmission process through grain boundaries in Ni3Al

    International Nuclear Information System (INIS)

    Robertson, I.M.; Lee, T.C.; Subramanian, R.; Birnbaum, H.K.

    1992-01-01

    This paper reports on the conditions established in disordered FCC systems for predicting the slip system that will be activated by a grain boundary to relieve a local stress concentration that have been applied to the ordered FCC alloy Ni 3 Al. The slip transfer behavior in hypo-stoichiometric Ni 3 Al with (0.2 at. %B) and without boron was directly observed by performing the deformation experiments in situ in the transmission electron microscope. In the boron-free and boron-doped alloys, lattice dislocations were incorporated in the grain boundary, but did not show evidence of dissociation to grain boundary dislocations or of movement in the grain boundary plane. The stress concentration associated with the dislocation pileup at the grain boundary are relieved by the emission of dislocations from the grain boundary in the boron-doped alloy. The slip system initiated in the adjoining grain obeyed the conditions established for disordered FCC systems. In the boron-free alloy, the primary stress relief mechanism was grain-boundary cracking, although dislocation emission from the grain boundary also occurred and accompanied intergranular crack advance

  3. Hall–Petch and dislocation strengthening in graded nanostructured steel

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Hansen, Niels; Gao, Yukui

    2012-01-01

    The structure and strength of low carbon steel samples have been analyzed after plastic deformation by shot-peening and cold-rolling. The fine scale surface microstructure caused by shot-peening extends to ∼50 μm below the surface. The structure is graded and subdivided by dislocation boundaries...... is the average spacing between the low and high angle boundaries which subdivide the microstructure, σ0 is the friction stress and k2 is a number which is expressed in terms of structural parameters which have been determined by electron backscattered diffraction. It is found that calculated k2 values...... by comparison with the experimental profile based on hardness measurements, and good agreement is found. This result points to a wider application of the suggested method to derive the local flow stress in a deformed microstructure based on a measurement of the local boundary spacing and the stress...

  4. Cellular dislocations patterns in monolike silicon: Influence of stress, time under stress and impurity doping

    Science.gov (United States)

    Oliveira, V. A.; Rocha, M.; Lantreibecq, A.; Tsoutsouva, M. G.; Tran-Thi, T. N.; Baruchel, J.; Camel, D.

    2018-05-01

    Besides the well-known local sub-grain boundaries (SGBs) defects, monolike Si ingots grown by Directional Solidification present distributed background cellular dislocation structures. In the present work, the influence of stress level, time under stress, and doping by O and Ge, on the formation of dislocation cells in monolike silicon, is analysed. This is achieved by performing a comparative study of the dislocation structures respectively obtained during crystallisation of pilot scale monolike ingots on Czochralski (CZ) and monolike seeds, during annealing of Float Zone (FZ), CZ, and 1 × 1020 at/cm3 Ge-doped CZ (GCZ) samples, and during 4-point bending of FZ and GCZ samples at 1300 °C under resolved stresses of 0.3, 0.7 and 1.9 MPa during 1-20 h. Synchrotron X-ray White-beam Topography and Rocking Curve Imaging (RCI) are applied to visualize the dislocation arrangements and to quantify the spatial distribution of the associated lattice distortions. Annealed samples and samples bent under 0.3 MPa present dislocation structures corresponding to transient creep stages where dislocations generated from surface defects are propagating and multiplying in the bulk. The addition of the hardening element Ge is found to block the propagation of dislocations from these surface sources during the annealing test, and to retard dislocation multiplication during bending under 0.3 MPa. On the opposite, cellular structures corresponding to the final stationary creep stage are obtained both in the non-molten seeds and grown part of monolike ingots and in samples bent under 0.7 and 1.9 MPa. A comparative discussion is made of the dynamics of formation of these final dislocation structures during deformation at high temperature and monolike growth.

  5. Arthroscopic treatment of acromioclavicular dislocation

    Directory of Open Access Journals (Sweden)

    Mihai T. Gavrilă

    2017-11-01

    Full Text Available A thorough understanding of biomechanical function of both acromioclavicular (AC and coracoclavicular (CC ligaments, stimulated surgeons to repair high-grade AC dislocation using arthroscopic technique. This technique necessitates a clear understanding of shoulder anatomy, especially of the structures in proximity to the clavicle and coracoid process and experiences in arthroscopic surgery. The follow case describes an arthroscopic technique used to treat AC dislocation in young man 30 years old, who suffered an injury at right shoulder. Results were similar to those obtained using open surgery and this encouraged us to continue utilization of this method. As a conclusion, arthroscopic treatment of AC separation is one of the best options as surgical treatment. Early results suggested that immediate anatomic reduction of an acute AC separation usually provides satisfactory clinical results at intermediate-term follow-up.

  6. Recurrent Dislocation of the Patella

    OpenAIRE

    Ben?tez, Gustavo

    2015-01-01

    Purpose: To evaluate results of medial patellofemoral ligament (MPFL) reconstruction associated with lateral release and advancement of vastus medialis in recurrent dislocation of the patella. Methods: We retrospectively evaluated 11 patients with a mean follow-up of 19 months. Mean age was 23, mainly women. We did MPFL reconstruction with semitendinosus or gracilis tendon depending on BMI, associated with advancement of vastus medialis and lateral release. Results: Mean Kujala score improved...

  7. Lattice dislocation in Si nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Omar, M.S., E-mail: dr_m_s_omar@yahoo.co [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Taha, H.T. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq)

    2009-12-15

    Modified formulas were used to calculate lattice thermal expansion, specific heat and Bulk modulus for Si nanowires with diameters of 115, 56, 37 and 22 nm. From these values and Gruneisen parameter taken from reference, mean lattice volumes were found to be as 20.03 A{sup 3} for the bulk and 23.63, 29.91, 34.69 and 40.46 A{sup 3} for Si nanowire diameters mentioned above, respectively. Their mean bonding length was calculated to be as 0.235 nm for the bulk and 0.248, 0.269, 0.282 and 0.297 nm for the nanowires diameter mentioned above, respectively. By dividing the nanowires diameter on the mean bonding length, number of layers per each nanowire size was found to be as 230, 104, 65 and 37 for the diameters mentioned above, respectively. Lattice dislocations in 22 nm diameter wire were found to be from 0.00324 nm for the 1st central lattice to 0.2579 nm for the last surface lattice. Such dislocation was smaller for larger wire diameters. Dislocation concentration found to change in Si nanowires according to the proportionalities of surface thickness to nanowire radius ratios.

  8. Orientation and length scale effects on dislocation structure in highly oriented nanotwinned Cu

    DEFF Research Database (Denmark)

    Lu, Qiuhong; Huang, Xiaoxu; Hansen, Niels

    2017-01-01

    Highly oriented nanotwinned Cu has been compressed to 6% strain in directions 90 degrees, 0 degrees and 45 degrees with respect to the twin boundaries of the almost parallel twins. In the 90 degrees and 0 degrees compressed samples Mode I and Mode II dislocations and their interactions with twin ...

  9. The interaction of He with 1/2 110 edge dislocation in W and Mo

    International Nuclear Information System (INIS)

    Hosson, J.Th.M. de; Sleeswyk, A.W.; Caspers, L.M.; Heugten, W. van; Veen, A. van.

    1976-01-01

    The positions of the metal atoms around a 1/2 [110] edge dislocation in Mo and W are calculated using the Wilson-Johnson potentials. The boundary conditions are given by anisotropic elasticity theory. The He-metal potential, also developed by Wilson and Johnson, is used to calculate the position with maximum energy gain for a He-atom. (author)

  10. The role of dislocation channeling in IASCC initiation of neutron irradiated stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, Kale J., E-mail: kalejs@umich.edu; Was, Gary S.

    2016-12-01

    This study intended to understand how dislocation channeling affects IASCC initiation using a novel four-point bend test. Stainless steels used in this study (irradiated in the BOR-60 reactor) included a commercial purity 304L alloy irradiated to 5.5, 10.2, and 47.5 dpa, and two high purity alloys, Fe−18Cr−12Ni and Fe−18Cr−25Ni, irradiated to ∼10 dpa. IASCC was enhanced by MnS inclusions, which dissolve in the NWC environment and form oxide caps, creating a crevice condition with a high propensity for crack initiation. Stress concentration at the grain boundary intersecting these sites induced crack initiation, resulting from discontinuous dislocation channels (DC). Stress to initiate IASCC decreased with dose due to earlier DC initiation. The HP Fe−18Cr−12Ni alloy had low IASCC susceptibility and the high Ni alloy did not crack. The difference was attributed to the propensity for DCs to transmit across grain boundaries, which controls stress accumulation at DC – grain boundary intersections. - Highlights: • MnS inclusions enhance susceptibility to IASCC initiation. • Local stress (typically caused by an intersecting dislocation channel) was required to cause cracking at a MnS inclusion. • The remotely applied stress at which IASCC initiation occurred decreased with increasing irradiation dose. • IASCC resistant alloys were more likely to transmit dislocation channels across grain boundaries.

  11. Mobilities and dislocation energies of planar faults in an ordered A 3 ...

    Indian Academy of Sciences (India)

    Present work describes the stability of possible planar faults of the A3B (D019) phase with an axial ratio less than the ideal. Mobilities and dislocation energies of various planar faults viz. antiphase boundaries (APBs), superlattice intrinsic stacking faults (SISFs) and complex stacking faults (CSFs) have been computed using ...

  12. Atraumatic Anterior Dislocation of the Hip Joint

    Directory of Open Access Journals (Sweden)

    Tadahiko Ohtsuru

    2015-01-01

    Full Text Available Dislocation of the hip joint in adults is usually caused by high-energy trauma such as road traffic accidents or falls from heights. Posterior dislocation is observed in most cases. However, atraumatic anterior dislocation of the hip joint is extremely rare. We present a case of atraumatic anterior dislocation of the hip joint that was induced by an activity of daily living. The possible causes of this dislocation were anterior capsule insufficiency due to developmental dysplasia of the hip, posterior pelvic tilt following thoracolumbar kyphosis due to vertebral fracture, and acetabular anterior coverage changes by postural factor. Acetabular anterior coverage changes in the sagittal plane were measured using a tomosynthesis imaging system. This system was useful for elucidation of the dislocation mechanism in the present case.

  13. Imaging findings of anterior hip dislocations

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Kyle [Mallinckrodt Institute of Radiology, Department of Radiology, St. Louis, MO (United States); Leslie, Michael [Yale School of Medicine, Department of Orthopedics and Rehabilitation, New Haven, CT (United States); Menn, Kirsten; Haims, Andrew [Yale University School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, CT (United States)

    2017-06-15

    Anterior hip dislocations are rare orthopedic emergencies resulting from high-energy trauma and have unique imaging characteristics on radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Imaging findings on CT and MRI allow for the prompt recognition and classification of anterior hip dislocations, which guides patient management and reduces complications. The purpose of this article is to review imaging findings of anterior hip dislocations, specifically focusing on CT and MRI. (orig.)

  14. Imaging findings of anterior hip dislocations

    International Nuclear Information System (INIS)

    Pfeifer, Kyle; Leslie, Michael; Menn, Kirsten; Haims, Andrew

    2017-01-01

    Anterior hip dislocations are rare orthopedic emergencies resulting from high-energy trauma and have unique imaging characteristics on radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Imaging findings on CT and MRI allow for the prompt recognition and classification of anterior hip dislocations, which guides patient management and reduces complications. The purpose of this article is to review imaging findings of anterior hip dislocations, specifically focusing on CT and MRI. (orig.)

  15. Dislocations and Plasticity in bcc Transition Metals at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L H; Tang, M; Moriarty, J A

    2009-01-23

    Using first-principles electronic structure calculations, quantum-based atomistic simulations and atomistically informed dislocation dynamics (DD) simulations, we have studied individual dislocation behavior and the multiscale modeling of single-crystal plasticity in the prototype bcc transition metals Ta, Mo and V under both ambient and high pressure conditions. The primary focus in this work is on the pressure-dependent structure, mobility and interaction of a/2<111> screw dislocations, which dominate the plastic deformation properties of these materials. At the electronic scale, first-principles calculations of elasticity, ideal strength and generalized stacking fault energy surfaces have been used to validate quantum-based multi-ion interatomic potentials. At the atomistic scale, these potentials have been used in flexible Green's function boundary condition simulations to study the core structure, Peierls stress {tau}{sub P}, thermally activated kink-pair formation and mobility below {tau}{sub P}, and phonon-drag mobility above {tau}{sub P}. These results have then been distilled into analytic velocity laws and used directly in predictive microscale DD simulations of flow stress and resolved yield stress over wide ranges of pressure, temperature and strain rate.

  16. [Traumatic lumbosacral dislocation - an underrated injury].

    Science.gov (United States)

    Schroeter, S; Weise, K; Badke, A

    2009-01-01

    Traumatic lumbosacral dislocations are rare. We report two cases with initially missed posttraumatic lumbosacral dislocations. The reported cases and the review of the literature show that, especially, accident victims with multiple fractures of the lumbar transverses processes may require a CT scan to confirm fractures or dislocations of L5/S1. Follow-up examinations due to persisting pain after physiotherapy should include lateral X-rays of the lumbar spine of the patient standing. According to the literature and our experience, the treatment of traumatic lumbosacral dislocation usually consists of open reduction and postero-lateral or dorso-ventral fusion of the unstable segments.

  17. Structure of the Dislocation in Sapphire

    DEFF Research Database (Denmark)

    Bilde-Sørensen, Jørgen; Thölen, A. R.; Gooch, D. J.

    1976-01-01

    Experimental evidence of the existence of 01 0 dislocations in the {2 0} prism planes in sapphire has been obtained by transmission electron microscopy. By the weak-beam technique it has been shown that the 01 0 dislocations may dissociate into three partials. The partials all have a Burgers vector...... of ⅓ 01 0 and are separated by two identical faults. The distance between two partials is in the range 75-135 Å, corresponding to a fault energy of 320±60 mJ/m2. Perfect 01 0 dislocations have also been observed. These dislocations exhibited either one or two peaks when imaged in the (03 0) reflection...

  18. Metal working and dislocation structures

    DEFF Research Database (Denmark)

    Hansen, Niels

    2007-01-01

    Microstructural observations are presented for different metals deformed from low to high strain by both traditional and new metal working processes. It is shown that deformation induced dislocation structures can be interpreted and analyzed within a common framework of grain subdivision on a finer...... and finer scale down to the nanometer dimension, which can be reached at ultrahigh strains. It is demonstrated that classical materials science and engineering principles apply from the largest to the smallest structural scale but also that new and unexpected structures and properties characterize metals...

  19. Dynamics of twin boundaries in martensites

    Energy Technology Data Exchange (ETDEWEB)

    Barsch, G.R.; Horovitz, B.; Krumhansl, J.A.

    1987-09-14

    The theory of forming a coherent twinning array in a parent phase is studied for a tetragonal to orthorhombic displacive transition. We find that this structure can be stabilized without the use of dislocations by a long-range interaction between the twin boundaries which is mediated via the parent phase. The dynamics of the twin boundary lattice consists of elementary excitations with surprisingly low frequency and a limiting -- (wave vector)/sup 1/2/ dispersion.

  20. Plastic deformation of crystals: analytical and computer simulation studies of dislocation glide

    Energy Technology Data Exchange (ETDEWEB)

    Altintas, S.

    1978-05-01

    The plastic deformation of crystals is usually accomplished through the motion of dislocations. The glide of a dislocation is impelled by the applied stress and opposed by microstructural defects such as point defects, voids, precipitates and other dislocations. The planar glide of a dislocation through randomly distributed obstacles is considered. The objective of the present research work is to calculate the critical resolved shear stress (CRSS) for athermal glide and the velocity of the dislocation at finite temperature as a function of the applied stress and the nature and strength of the obstacles. Dislocation glide through mixtures of obstacles has been studied analytically and by computer simulation. Arrays containing two kinds of obstacles as well as square distribution of obstacle strengths are considered. The critical resolved shear stress for an array containing obstacles with a given distribution of strengths is calculated using the sum of the quadratic mean of the stresses for the individual obstacles and is found to be in good agreement with the computer simulation data. Computer simulation of dislocation glide through randomly distributed obstacles containing up to 10/sup 6/ obstacles show that the CRSS decreases as the size of the array increases and approaches a limiting value. Histograms of forces and of segment lengths are obtained and compared with theoretical predictions. Effects of array shape and boundary conditions on the dislocation glide are also studied. Analytical and computer simulation results are compared with experimental results obtained on precipitation-, irradiation-, forest-, and impurity cluster-hardening systems and are found to be in good agreement.

  1. Plastic deformation of crystals: analytical and computer simulation studies of dislocation glide

    International Nuclear Information System (INIS)

    Altintas, S.

    1978-05-01

    The plastic deformation of crystals is usually accomplished through the motion of dislocations. The glide of a dislocation is impelled by the applied stress and opposed by microstructural defects such as point defects, voids, precipitates and other dislocations. The planar glide of a dislocation through randomly distributed obstacles is considered. The objective of the present research work is to calculate the critical resolved shear stress (CRSS) for athermal glide and the velocity of the dislocation at finite temperature as a function of the applied stress and the nature and strength of the obstacles. Dislocation glide through mixtures of obstacles has been studied analytically and by computer simulation. Arrays containing two kinds of obstacles as well as square distribution of obstacle strengths are considered. The critical resolved shear stress for an array containing obstacles with a given distribution of strengths is calculated using the sum of the quadratic mean of the stresses for the individual obstacles and is found to be in good agreement with the computer simulation data. Computer simulation of dislocation glide through randomly distributed obstacles containing up to 10 6 obstacles show that the CRSS decreases as the size of the array increases and approaches a limiting value. Histograms of forces and of segment lengths are obtained and compared with theoretical predictions. Effects of array shape and boundary conditions on the dislocation glide are also studied. Analytical and computer simulation results are compared with experimental results obtained on precipitation-, irradiation-, forest-, and impurity cluster-hardening systems and are found to be in good agreement

  2. Dislocation

    Science.gov (United States)

    ... There is no substitute for close supervision, no matter how safe the environment or situation appears to ... ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer Support Get email updates Subscribe to RSS Follow ...

  3. Incidental Education (for Women) in Rural Communities.

    Science.gov (United States)

    Crosby, Valmai

    The Country Women's Association (CWA) is a nationwide Australian group that started in the 1920s in response to isolated women's need to socialize. The group's activities have expanded greatly over time. It distributes essential food and clothing to needy rural families, and its extensive involvement in incidental education for women includes…

  4. Incidental cancer in multinodular goitre post thyroidectomy

    African Journals Online (AJOL)

    anterior neck mass, but other nodules may be detected incidentally during radiological evaluation of the neck. ..... Our 5.7% false-negative rate for FNAB in detecting cancer is similar to the findings of Rumstadt et al. ... our institution most of these cases are treated medically with antithyroid medication followed by radioactive.

  5. Incidental fear cues increase monetary loss aversion.

    Science.gov (United States)

    Schulreich, Stefan; Gerhardt, Holger; Heekeren, Hauke R

    2016-04-01

    In many everyday decisions, people exhibit loss aversion-a greater sensitivity to losses relative to gains of equal size. Loss aversion is thought to be (at least partly) mediated by emotional--in particular, fear-related--processes. Decision research has shown that even incidental emotions, which are unrelated to the decision at hand, can influence decision making. The effect of incidental fear on loss aversion, however, is thus far unclear. In two studies, we experimentally investigated how incidental fear cues, presented during (Study 1) or before (Study 2) choices to accept or reject mixed gambles over real monetary stakes, influence monetary loss aversion. We find that the presentation of fearful faces, relative to the presentation of neutral faces, increased risk aversion-an effect that could be attributed to increased loss aversion. The size of this effect was moderated by psychopathic personality: Fearless dominance, in particular its interpersonal facet, but not self-centered impulsivity, attenuated the effect of incidental fear cues on loss aversion, consistent with reduced fear reactivity. Together, these results highlight the sensitivity of loss aversion to the affective context. (c) 2016 APA, all rights reserved).

  6. Incidental learning in second language acquisition

    NARCIS (Netherlands)

    Hulstijn, J.H.; Chapelle, C.A.

    2013-01-01

    The term incidental learning is used, in applied linguistics, to refer to the acquisition of a word or expression without the conscious intention to commit the element to memory, such as "picking up" an unknown word from listening to someone or from reading a text.

  7. Hybrid dislocated control and general hybrid projective dislocated synchronization for the modified Lue chaotic system

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yuhua [College of Information Science and Technology, Donghua University, Shanghai 201620 (China) and Department of Maths, Yunyang Teacher' s College, Hubei 442000 (China)], E-mail: yuhuaxu2004@163.com; Zhou Wuneng [College of Information Science and Technology, Donghua University, Shanghai 201620 (China)], E-mail: wnzhou@163.com; Fang Jianan [College of Information Science and Technology, Donghua University, Shanghai 201620 (China)

    2009-11-15

    This paper introduces a modified Lue chaotic system, and some basic dynamical properties are studied. Based on these properties, we present hybrid dislocated control method for stabilizing chaos to unstable equilibrium and limit cycle. In addition, based on the Lyapunov stability theorem, general hybrid projective dislocated synchronization (GHPDS) is proposed, which includes complete dislocated synchronization, dislocated anti-synchronization and projective dislocated synchronization as its special item. The drive and response systems discussed in this paper can be strictly different dynamical systems (including different dimensional systems). As examples, the modified Lue chaotic system, Chen chaotic system and hyperchaotic Chen system are discussed. Numerical simulations are given to show the effectiveness of these methods.

  8. Parallel glide: flow of dislocations with internal stress source/sink distribution

    Directory of Open Access Journals (Sweden)

    Karlo T Raić

    2008-01-01

    Full Text Available The unexpected glide of dislocations on a plane parallel to the film/substrate interface in ultrathin copper films, which has been called parallel glide (Balk et al 2003 Acta Metall. 51 447, is described using an analytical model. The phenomenon is observed as a problem involving inlet/outlet flow from different positions of a grain boundary into the grain channel. In this sense, parallel glide is presented as the flow of dislocations with an internal stress source/sink distribution.

  9. Grain boundary strength as point defect sink strength

    International Nuclear Information System (INIS)

    Volobuev, A.V.; Gann, V.V.

    1987-01-01

    Sink strength of spherical grain boundary as an absolutely absorbing surface and as finite thickness wall consisting of the edge dislocations are considered. The values of the grain boundary sink strength are shown to be critically dependent on the point defect recombination degree

  10. Anterior bilateral temporomandibular joint dislocation: an ...

    African Journals Online (AJOL)

    Anterior dislocation of the temporomandibular joint (TMJ) though an infrequent presentation at the emergency department; often demands an immediate reduction to relieve discomfort and prevent adverse long-term sequelae. A simple and effective technique to reduce the dislocation is successfully demonstrated by putting ...

  11. Dislocation morphology in deformed and irradiated niobium

    International Nuclear Information System (INIS)

    Chang, C.P.

    1977-06-01

    Niobium foils of moderate purity were examined for the morphology of dislocations or defect clusters in the deformed or neutron-irradiated state by transmission electron microscopy. New evidence has been found for the dissociation of screw dislocations into partials on the (211) slip plane according to the Crussard mechanism: (a/2) [111] → (a/3) [111] + (a/6) [111

  12. On establishing coreference in Left Dislocation constructions ...

    African Journals Online (AJOL)

    The phenomenon of left dislocation (LD) has received relatively little attention in the generative literature. In Government & Binding theory and early versions of Minimalist Syntax, the left-dislocated expression is conventionally taken to be base-generated in its sentence-initial surface position and the resumptive pronoun in ...

  13. Traumatic atlantooccipital dislocation: two cases with survival.

    Science.gov (United States)

    Bools, J C; Rose, B S

    1986-01-01

    These two cases with long-term survival after anterior and posterior AO dislocation point out the importance of making the diagnosis. Our simple technique of rapid CT confirmation of AO dislocation is a practical adjuvant procedure, particularly in patients with suspected intracranial injury.

  14. Palmar dislocation of scaphoid and lunate

    Directory of Open Access Journals (Sweden)

    Khalid Koulali Idrissi

    2011-11-01

    Full Text Available A palmar dislocation of scaphoid and lunate is uncommon. We have found only 19 reported cases in the literature. We reported a simultaneous, divergent dislocation. The closed reduction followed by percutaneous pinning has given a good result without avascular necrosis of any carpal bone.

  15. Re-dislocation after revision total hip arthroplasty for recurrent dislocation: a multicentre study.

    Science.gov (United States)

    Yoshimoto, Kensei; Nakashima, Yasuharu; Aota, Shigeo; Kaneuji, Ayumi; Fukui, Kiyokazu; Hirakawa, Kazuo; Nakura, Nariaki; Kinoshita, Koichi; Naito, Masatoshi; Iwamoto, Yukihide

    2017-02-01

    Although most case of dislocations after total hip arthroplasty (THA) can be managed with conservative treatment, recurrent dislocation may require surgical intervention. This multicentre study was conducted to evaluate the re-dislocation rate after revision THA for recurrent dislocation, and to determine the risk factors for re-dislocation. We retrospectively reviewed the 88 hips in 88 patients who underwent revision THA for recurrent dislocation at five institutions between 1995 and 2014. The mean patient age at surgery was 68.5 years and the mean follow-up period was 53.1 months. Multivariate logistic regression was performed to identify risk factors for re-dislocation. Sixteen hips in 16 patients (18.2 %) re-dislocated at a mean of 25.5 months (range, 1-83 months) after revision THA. Multivariate analysis identified osteonecrosis of the femoral head (odds ratio [OR] = 5.62 vs. osteoarthritis) and a femoral head size hips required additional revision THA for re-dislocation. The re-dislocation rate after revision THA for recurrent dislocation remains high, suggesting the need for prevention measures. We recommend the use of a femoral head size ≥ 32 mm.

  16. Estimation of dislocations density and distribution of dislocations during ECAP-Conform process

    Science.gov (United States)

    Derakhshan, Jaber Fakhimi; Parsa, Mohammad Habibi; Ayati, Vahid; Jafarian, Hamidreza

    2018-01-01

    Dislocation density of coarse grain aluminum AA1100 alloy (140 µm) that was severely deformed by Equal Channel Angular Pressing-Conform (ECAP-Conform) are studied at various stages of the process by electron backscattering diffraction (EBSD) method. The geometrically necessary dislocations (GNDs) density and statistically stored dislocations (SSDs) densities were estimate. Then the total dislocations densities are calculated and the dislocation distributions are presented as the contour maps. Estimated average dislocations density for annealed of about 2×1012 m-2 increases to 4×1013 m-2 at the middle of the groove (135° from the entrance), and they reach to 6.4×1013 m-2 at the end of groove just before ECAP region. Calculated average dislocations density for one pass severely deformed Al sample reached to 6.2×1014 m-2. At micrometer scale the behavior of metals especially mechanical properties largely depend on the dislocation density and dislocation distribution. So, yield stresses at different conditions were estimated based on the calculated dislocation densities. Then estimated yield stresses were compared with experimental results and good agreements were found. Although grain size of material did not clearly change, yield stress shown intensive increase due to the development of cell structure. A considerable increase in dislocations density in this process is a good justification for forming subgrains and cell structures during process which it can be reason of increasing in yield stress.

  17. Dislocation evolution during plastic deformation: Equations vs. discrete dislocation dynamics study

    Science.gov (United States)

    Davoudi, Kamyar M.; Vlassak, Joost J.

    2018-02-01

    Equations for dislocation evolution bridge the gap between dislocation properties and continuum descriptions of plastic behavior of crystalline materials. Computer simulations can help us verify these evolution equations and find their fitting parameters. In this paper, we employ discrete dislocation dynamics to establish a continuum-based model for the evolution of the dislocation structure in polycrystalline thin films. Expressions are developed for the density of activated dislocation sources, as well as dislocation nucleation and annihilation rates. We demonstrate how size effect naturally enters the evolution equation. Good agreement between the simulation and the model results is obtained. The current approach is based on a two-dimensional discrete dislocation dynamics model but can be extended to three-dimensional models.

  18. Incidental Vocabulary Learning in Second Language Acquisition: A Literature Review

    Directory of Open Access Journals (Sweden)

    Falcon Dario Restrepo Ramos

    2015-01-01

    Full Text Available This literature review aims to analyze previous studies that address the incidental learning of vocabulary in second language acquisition. The articles included in this literature review look into the understanding of vocabulary learning through incidental means, the relationship of reading and incidental vocabulary learning, and the strategies and tasks that promote the incidental learning of vocabulary. The findings show that L2 learners develop much of their vocabulary by incidental means through exposure to words in informative contexts. Moreover, this exposure is promoted by reading, and enhanced through multimodal glosses. Further research may focus on listening for higher lexical retention rates, the circumstances that allow incidental learning of multi-word phrases and collocations, and the use of technology-based methods for incidental vocabulary acquisition.

  19. Rules for Forest Interactions between Dislocations

    International Nuclear Information System (INIS)

    Wickham, L. K.; Schwarz, K. W.; Stoelken, J. S.

    1999-01-01

    The dynamical interactions of dislocations existing on intersecting glide planes have been investigated using numerical simulations based on isotropic linear elastic theory. It is found that such dislocations either repel, attract and form growing junctions, or attract and form bound crossed states. Which of these occurs can be predicted from a surprisingly simple analysis of the initial configurations. The outcome is determined primarily by the angles which the dislocations initially make with the glide-plane intersection edge, and is largely independent of the initial distance between the dislocations, their initial curvature, or ambient applied stresses. The results provide a rule for dealing with forest interactions within the context of large multiple-dislocation computations. (c) 1999 The American Physical Society

  20. Dissociated dislocations in Ni: a computational study

    International Nuclear Information System (INIS)

    Szelestey, P.; Patriarca, M.; Kaski, K.

    2005-01-01

    A systematic computational study of the behavior of a (1/2) dissociated screw dislocation in fcc nickel is presented, in which atomic interactions are described through an embedded-atom potential. A suitable external stress is applied on the system, both for modifying the equilibrium separation distance d and moving the dislocation complex. The structure of the dislocation and its corresponding changes during the motion are studied in the framework of the two-dimensional Peierls model, for different values of the ratio d/a', where a' is the period of the Peierls potential. The distance between the edge and screw components of the partials, as well as their widths, undergo a modulation with period a', as the dislocation moves, and the amplitudes of such oscillations are shown to depend on d/a'. The stress profile acting on the dislocation complex is analyzed and the effective Peierls stress is estimated for different values of d/a'

  1. Defining the Parameters of Incidental Learning on a Serial Reaction Time (SRT) Task: Do Conscious Rules Apply?

    Science.gov (United States)

    Barker, Lynne A

    2012-12-17

    There is ongoing debate about the contribution of explicit processes to incidental learning, particularly attention, working memory and control mechanisms. Studies generally measure explicit process contributions to incidental learning by comparing dual- to single-task sequence learning on some variant of a Serial Reaction Time (SRT), usually adopting an auditory tone counting task as the secondary task/memory load. Few studies have used secondary working memory stimuli with the SRT task, those that have typically presented secondary stimuli, before, after or between primary task stimuli. Arguably, this design is problematic because participants may potentially "switch" attention between sequential stimulus sources limiting the potential of both tasks to simultaneously index shared cognitive resources. In the present study secondary Visual and Verbal, memory tasks were temporally synchronous and spatially embedded with the primary SRT task for Visual and Verbal dual-task conditions and temporally synchronous but spatially displaced for Visual-Spatial and Verbal-Spatial Above/Below conditions, to investigate modality specific contributions of visual, verbal and spatial memory to incidental and explicit sequence learning. Incidental learning scores were not different as an effect of condition but explicit scores were. Explicit scores significantly and incrementally diminished from the Single-task through Visual-Spatial Below conditions; percentage accuracy scores on secondary tasks followed a significant corresponding pattern suggesting an explicit learning/secondary memory task trade-off as memory demands of tasks increased across condition. Incidental learning boundary conditions are unlikely to substantially comprise working memory processes.

  2. Influence of mobile dislocations on phase separation in binary alloys

    International Nuclear Information System (INIS)

    Haataja, Mikko; Leonard, Francois

    2004-01-01

    We introduce a continuum model to describe the phase separation of a binary alloy in the presence of mobile dislocations. The kinetics of the local composition and dislocation density are coupled through their elastic fields. We show both analytically and numerically that mobile dislocations modify the standard spinodal decomposition process, and lead to several regimes of growth. Depending on the dislocation mobility and observation time, the phase separation may be accelerated, decelerated, or unaffected by mobile dislocations. For any finite dislocation mobility, we show that the domain growth rate asymptotically becomes independent of the dislocation mobility, and is faster than the dislocation-free growth rate

  3. The peculiar effect of forest dislocations on single twin layer development in zinc and beryllium single crystals

    International Nuclear Information System (INIS)

    Lavrentev, F.F.; Bosin, M.E.

    1978-01-01

    This is an investigation of the effect of different types of forest dislocation on the rate of twin layer broadening, Vsub(n), in zinc and beryllium crystals, and on the velocity of the twinning dislocation movement, Vsub(t), in zinc crystals under the action of a constant external shear stress. Increasing the forest basal dislocation density, rhosub(b), was found to result in increasing Vsub(n) and reducing Vsub(t), while increasing the forest pyramidal dislocation density, rhosub(p), causes Vsub(n) to decrease. An analysis in terms of crystal geometry shows that the dualism of the influence of the basal dislocations stems from the fact that they behave as twinning dislocation sources whose density, increasing with rhosub(b) leads to higher Vsub(n). The decrease in the effective stress, tausup(*), with increasing rhosub(b) is estimated. An analysis of the experimental data yielded the relation Vsub(t)(tausup(*)) and an estimate of the activation volume, which amounted to 6 x 10 -21 cm 3 . The close coincidence of the activation volumes as obtained from Vsub(t)(tausup(*)) and Vsub(n)(tau) suggests that the rate-controlling mechanism of the twin layer development in zinc crystals with large forest basal dislocation density is the twinning dislocation inhibition. In Be crystals, the increasing Vsub(n) effect is observed during untwinning. In Be twinned crystals, electron microscopy revealed twinning dislocations with a density of about 10 5 cm -1 at the twin boundaries and a large forest basal dislocation density inside the twin (ca. 10 8 cm -2 ). (Auth.)

  4. Recurrent Dislocation of the Patella

    Science.gov (United States)

    Benítez, Gustavo

    2015-01-01

    Purpose: To evaluate results of medial patellofemoral ligament (MPFL) reconstruction associated with lateral release and advancement of vastus medialis in recurrent dislocation of the patella. Methods: We retrospectively evaluated 11 patients with a mean follow-up of 19 months. Mean age was 23, mainly women. We did MPFL reconstruction with semitendinosus or gracilis tendon depending on BMI, associated with advancement of vastus medialis and lateral release. Results: Mean Kujala score improved from 46,54 pts. preoperative to 88,36 postoperative. Our main complication was 1 patient with rigid knee, who required movilization under anesthesia and arthroscopic arthrolisis to improve her outcome. Conclusion: The combination of this techniques are a good alternative to treat patients with recurrent patella disclocation, with good short and mid-term results. Biomechanic intra and postop complications of MPFL reconstruction are related to patellar fixation, anatomic positioning of femoral tunnel and knee position of the graft fixation.

  5. Stage IV work-hardening related to disorientations in dislocation structures

    DEFF Research Database (Denmark)

    Pantleon, W.

    2004-01-01

    The effect of deformation-induced disorientations on the work-hardening of metals is modelled based on dislocation dynamics. Essentially, Kocks’ dislocation model describing stage III hardening is extended to stage IV by incorporation of excess dislocations related to the disorientations....... Disorientations evolving from purely statistical reasons — leading to a square root dependence of the average disorientation angle on strain — affect the initial work-hardening rate (and the saturation stress) of stage III only slightly. On the other hand, deterministic contributions to the development...... of disorientations, as differences in the activated slip systems across boundaries, cause a linear increase of the flow stress at large strains. Such a constant work-hardening rate is characteristic for stage IV....

  6. Evolution, Interaction, and Intrinsic Properties of Dislocations in Intermetallics: Anisotropic 3D Dislocation Dynamics Approach

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qian [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    The generation, motion, and interaction of dislocations play key roles during the plastic deformation process of crystalline solids. 3D Dislocation Dynamics has been employed as a mesoscale simulation algorithm to investigate the collective and cooperative behavior of dislocations. Most current research on 3D Dislocation Dynamics is based on the solutions available in the framework of classical isotropic elasticity. However, due to some degree of elastic anisotropy in almost all crystalline solids, it is very necessary to extend 3D Dislocation Dynamics into anisotropic elasticity. In this study, first, the details of efficient and accurate incorporation of the fully anisotropic elasticity into 3D discrete Dislocation Dynamics by numerically evaluating the derivatives of Green's functions are described. Then the intrinsic properties of perfect dislocations, including their stability, their core properties and disassociation characteristics, in newly discovered rare earth-based intermetallics and in conventional intermetallics are investigated, within the framework of fully anisotropic elasticity supplemented with the atomistic information obtained from the ab initio calculations. Moreover, the evolution and interaction of dislocations in these intermetallics as well as the role of solute segregation are presented by utilizing fully anisotropic 3D dislocation dynamics. The results from this work clearly indicate the role and the importance of elastic anisotropy on the evolution of dislocation microstructures, the overall ductility and the hardening behavior in these systems.

  7. Ultrasonic Study of Dislocation Dynamics in Lithium -

    Science.gov (United States)

    Han, Myeong-Deok

    1987-09-01

    Experimental studies of dislocation dynamics in LiF single crystals, using ultrasonic techniques combined with dynamic loading, were performed to investigate the time evolution of the plastic deformation process under a short stress pulse at room temperature, and the temperature dependence of the dislocation damping mechanism in the temperature range 25 - 300(DEGREES)K. From the former, the time dependence of the ultrasonic attenuation was understood as resulting from dislocation multiplication followed by the evolution of mobile dislocations to immobile ones under large stress. From the latter, the temperature dependence of the ultrasonic attenuation was interpreted as due to the motion of the dislocation loops overcoming the periodic Peierls potential barrier in a manner analogous to the motion of a thermalized sine-Gordon chain under a small stress. The Peierls stress obtained from the experimental results by application of Seeger's relaxation model with exponential dislocation length distribution was 4.26MPa, which is consistent with the lowest stress for the linear relation between the dislocation velocity and stress observed by Flinn and Tinder.

  8. The separate roles of subgrains and forest dislocations in the isotropic hardening of type 304 stainless steel

    International Nuclear Information System (INIS)

    Kassner, M.E.; Miller, A.K.; Sherby, O.D.

    1982-01-01

    Tests on 304 stainless steel were conducted involving first warm working in torsion, then cold working in torsion, and finally measurement of the elevated-temperature yield strength in compression. These tests permitted separation of the effects of subgrain size and forest dislocation density on the isotropic part of the flow stress. Forest dislocation strengthening appears to dominate in this material. Th results are best fitted by a root-mean-square summation of strength terms representing the contributions of solutes, forest dislocations, and subgrain boundaries. The same equation successfully predicts the flow stress during elevated-temperature transient deformation (under both constant strain rate and variable strain rate) from the transient dislocation substructure

  9. Dislocation-based plasticity and strengthening mechanisms in sub-20 nm lamellar structures in pearlitic steel wire

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Hansen, Niels; Godfrey, Andrew

    2016-01-01

    The tensile properties and the deformation microstructure of pearlitic steel (0.8 wt % C) have been quantified in wires drawn to strains in the range from 3.7 to 5.4, having a flow stress in the range from 3.5 to 4.5 GPa. With increasing strain the interlamellar spacing (ILS) decreases from about...... at a strain of 5.4; the dislocations are stored as threading dislocations, as dislocation tangles and as cell boundaries with low to medium misorientation angles. An analysis of the evolution of microstructure and strength with increasing strain suggests that dislocation-based plasticity is a dominating...... the calculated and the measured flow stress is observed over the strain range 0e5.4. However at large strains beyond 3.7 deviations are observed which are discussed in terms of the applied strength-structure relationships....

  10. Distribution of distances between dislocations in different types of dislocation substructures in deformed Cu-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Trishkina, L., E-mail: trishkina.53@mail.ru; Zboykova, N.; Koneva, N., E-mail: koneva@tsuab.ru; Kozlov, E. [Tomsk State University of Architecture and Building, 2 Solyanaya St., Tomsk, 634003 (Russian Federation); Cherkasova, T. [Tomsk State University of Architecture and Building, 2 Solyanaya St., Tomsk, 634003 (Russian Federation); National Research Tomsk Polytechnic University, 50 Lenin Ave., Tomsk, 634050 (Russian Federation)

    2016-01-15

    The aim of the investigation was the determination of the statistic description of dislocation distribution in each dislocation substructures component forming after different deformation degrees in the Cu-Al alloys. The dislocation structures were investigated by the transmission diffraction electron microscopy method. In the work the statistic description of distance distribution between the dislocations, dislocation barriers and dislocation tangles in the deformed Cu-Al alloys with different concentration of Al and test temperature at the grain size of 100 µm was carried out. It was established that the above parameters influence the dislocation distribution in different types of the dislocation substructures (DSS): dislocation chaos, dislocation networks without disorientation, nondisoriented and disoriented cells, in the walls and inside the cells. The distributions of the distances between dislocations in the investigated alloys for each DSS type formed at certain deformation degrees and various test temperatures were plotted.

  11. Distribution of distances between dislocations in different types of dislocation substructures in deformed Cu-Al alloys

    Science.gov (United States)

    Trishkina, L.; Cherkasova, T.; Zboykova, N.; Koneva, N.; Kozlov, E.

    2016-01-01

    The aim of the investigation was the determination of the statistic description of dislocation distribution in each dislocation substructures component forming after different deformation degrees in the Cu-Al alloys. The dislocation structures were investigated by the transmission diffraction electron microscopy method. In the work the statistic description of distance distribution between the dislocations, dislocation barriers and dislocation tangles in the deformed Cu-Al alloys with different concentration of Al and test temperature at the grain size of 100 µm was carried out. It was established that the above parameters influence the dislocation distribution in different types of the dislocation substructures (DSS): dislocation chaos, dislocation networks without disorientation, nondisoriented and disoriented cells, in the walls and inside the cells. The distributions of the distances between dislocations in the investigated alloys for each DSS type formed at certain deformation degrees and various test temperatures were plotted.

  12. Incidental Cardiac Findings on Thoracic Imaging.

    LENUS (Irish Health Repository)

    Kok, Hong Kuan

    2013-02-07

    The cardiac structures are well seen on nongated thoracic computed tomography studies in the investigation and follow-up of cardiopulmonary disease. A wide variety of findings can be incidentally picked up on careful evaluation of the pericardium, cardiac chambers, valves, and great vessels. Some of these findings may represent benign variants, whereas others may have more profound clinical importance. Furthermore, the expansion of interventional and surgical practice has led to the development and placement of new cardiac stents, implantable pacemaker devices, and prosthetic valves with which the practicing radiologist should be familiar. We present a collection of common incidental cardiac findings that can be readily identified on thoracic computed tomography studies and briefly discuss their clinical relevance.

  13. Thermodynamic theory of dislocation-enabled plasticity

    Science.gov (United States)

    Langer, J. S.

    2017-11-01

    The thermodynamic theory of dislocation-enabled plasticity is based on two unconventional hypotheses. The first of these is that a system of dislocations, driven by external forces and irreversibly exchanging heat with its environment, must be characterized by a thermodynamically defined effective temperature that is not the same as the ordinary temperature. The second hypothesis is that the overwhelmingly dominant mechanism controlling plastic deformation is thermally activated depinning of entangled pairs of dislocations. This paper consists of a systematic reformulation of this theory followed by examples of its use in analyses of experimentally observed phenomena including strain hardening, grain-size (Hall-Petch) effects, yielding transitions, and adiabatic shear banding.

  14. Neglected dorsal dislocation of the scaphoid

    Directory of Open Access Journals (Sweden)

    Amaravati Rajkumar

    2009-01-01

    Full Text Available Isolated dislocation of the scaphoid is very rare. A 45-year old male, industrial worker reported two and half months after injury with wrist pain and swelling on the dorsum of left wrist. He was diagnosed as neglected dorsal dislocation of scaphoid. Proximal row carpectomy with capsular interposition was done stabilizing the distal carpus on the radius using Kirschner wires. At-12 months follow-up the patient had good wrist function and was satisfied with the outcome of the treatment. We hereby report this neglected dorsal dislocation of scaphoid in view of rarity and discuss the various options for management.

  15. Incidental Anterior Cruciate Ligament Calcification: Case Report.

    Science.gov (United States)

    Hayashi, Hisami; Fischer, Hans

    2016-03-01

    The calcification of knee ligaments is a finding noted only in a handful of case reports. The finding of an anterior cruciate ligament calcification has been reported once in the literature. Comparable studies involving the posterior cruciate ligament, medial collateral ligament and an ossicle within the anterior cruciate ligament are likewise discussed in reports of symptomatic patients. We report a case of incidentally discovered anterior cruciate ligament calcification. We discuss the likely etiology and clinical implications of this finding.

  16. The core structure of a Frank dislocation in Ni3(Al,Nb)

    International Nuclear Information System (INIS)

    Bonnet, R.; Loubradou, M.; Derder, C.; Catana, A.

    1991-01-01

    This paper reports on the core structures of dislocations in L1 2 crystals, in view of understanding the anomalous yield behavior of strength with increasing temperature. Theoretical approaches have been proposed for explaining the dissociations of these dislocations, and experimental evidences have been reported for such dissociations using either the weak beam technique or more recently the HRTEM (High Resolution Transmission Electron Microscopy) technique. Recent HRTEM results show that for Ni 3 A1 the partial dislocations 1/2 left-angle 110 right-angle which limit an APB (Antiphase Boundary) lying on (001) are only split over 0.1 - 0.3 nm along (111) planes, producing very high energy CSF's (Complex Stacking Faults) which limit an SISF (superlattice Intrinsic Stacking Fault) extended on a (111) plane. Concerning the 1/2 left-angle 111 right-angle Frank dislocation, which limits an SESF (Superlattice Extrinsic Stacking Fault), there are no reported results yet. Let us note, however, that for aluminum HRTEM images of Frank dislocation loops have been studied. This lack of information in the L1 2 crystals motivated the present HRTEM study

  17. Asymptotic Analysis of a System of Algebraic Equations Arising in Dislocation Theory

    KAUST Repository

    Hall, Cameron L.

    2010-01-01

    The system of algebraic equations given by σn j=0, j≠=i sgn(xi-xj )|xi-xj|a = 1, i = 1, 2, ⋯ , n, x0 = 0, appears in dislocation theory in models of dislocation pile-ups. Specifically, the case a = 1 corresponds to the simple situation where n dislocations are piled up against a locked dislocation, while the case a = 3 corresponds to n dislocation dipoles piled up against a locked dipole. We present a general analysis of systems of this type for a > 0 and n large. In the asymptotic limit n→∞, it becomes possible to replace the system of discrete equations with a continuum equation for the particle density. For 0 < a < 2, this takes the form of a singular integral equation, while for a > 2 it is a first-order differential equation. The critical case a = 2 requires special treatment, but, up to corrections of logarithmic order, it also leads to a differential equation. The continuum approximation is valid only for i neither too small nor too close to n. The boundary layers at either end of the pile-up are also analyzed, which requires matching between discrete and continuum approximations to the main problem. © 2010 Society for Industrial and Applied Mathematics.

  18. Effects of cobalt on creep rupture properties and dislocation structures in nickel base superalloys

    International Nuclear Information System (INIS)

    Wang, W.Z.; Jin, T.; Jia, J.H.; Liu, J.L.; Hu, Z.Q.

    2015-01-01

    The influences of cobalt (Co) on creep rupture lives and dislocation structures in nickel base superalloys with and without rhenium (Re) are investigated. The creep rupture test conditions were high temperature low stress (1100 °C/150 MPa), intermediate temperature and stress (982 °C, 1010 °C) and low temperature high stress (850 °C/586 MPa). The results show that increasing Co content could enhance the creep rupture lives at low and intermediate temperature, and does not degrade the creep rupture lives of alloys at high temperature. In Re-containing alloys, at high temperature low stress (1100 °C/150 MPa), the effects of Co on the dislocation structures are negligible, while at low temperature high stress (850 °C/586 MPa), stacking faults are generated in alloy with 12% Co, and in alloy with 3% Co and free of Co, gamma prime particles are sheared by dislocation pairs. In Re-free alloys, at intermediate temperature and stress (1010 °C/248 MPa), large quantities of stacking faults appear in alloy without Co, while in alloy having 12% Co, gamma prime particles are sheared by dislocation pairs coupled by anti-phase boundary (APB). The gamma prime sheared by stacking faults or by dislocation pairs coupled by APB depends on the competition of stacking faults energy and APB energy which is affected by temperature and the interaction of Re and Co

  19. Prismatic dislocation loops and concentric dislocation loops in HPHT-grown diamond single crystals

    International Nuclear Information System (INIS)

    Yin, L.-W.; Li, M.-S.; Zou, Z.-D.; Gong, Z.-G.; Hao, Z.-Y.

    2003-01-01

    As-grown diamond single crystals grown from Fe-Ni-C system under high temperature-high pressure were examined by transmission electron microscopy. There exist prismatic dislocation loops and concentric dislocation loops in the diamond, which are related to the nonequilibrium nature of the diamond synthesis process. The prismatic dislocation loops may be formed by vacancy condensation during rapid cooling from high temperature, and the Burgers vector of the dislocation is determined by diffraction contrast as 1/2 . Moire fringes formed by two overlapping (1 1 1) close-packed planes were used to study concentric dislocation loops. The concentric dislocation loops may be derived from thermal stress caused by the inclusions in the diamond, which cause a strain field due to the thermal contraction difference between the inclusions and the diamond during cooling from high temperature

  20. Effect of pre-existing immobile dislocations on the evolution of geometrically necessary dislocations during fatigue

    Science.gov (United States)

    Irastorza-Landa, Ainara; Grilli, Nicolò; Van Swygenhoven, Helena

    2017-07-01

    The role of pre-existing mobile and immobile dislocation densities on the evolution of geometrical necessary dislocation densities (GNDs) during cyclic fatigue in shear is studied using a continuum dislocation-based model incorporated in a crystal plasticity finite element scheme. Clusters with different immobile dislocation densities are implemented in a homogeneous medium containing a certain mobile dislocation density. It is found that whether GND walls are formed around the initial immobile cluster (or not) strongly depends on the absolute values of initial mobile dislocation density and on the ratio between mobile and immobile densities. The results are discussed in terms of the apparent GND densities experimentally obtained using Laue micro-diffraction.

  1. Canonical Quantization of Crystal Dislocation and Electron-Dislocation Scattering in an Isotropic Media

    Science.gov (United States)

    Li, Mingda; Cui, Wenping; Dresselhaus, M. S.; Chen, Gang; MIT Team; Boston College Team

    Crystal dislocations govern the plastic mechanical properties of materials but also affect the electrical and optical properties. However, a fundamental and decent quantum-mechanical theory of dislocation remains undiscovered for decades. Here we present an exact and manageable Hamiltonian theory for both edge and screw dislocation line in an isotropic media, where the effective Hamiltonian of a single dislocation line can be written in a harmonic-oscillator-like form, with closed-form quantized 1D phonon-like excitation. Moreover a closed-form, position dependent electron-dislocation coupling strength is obtained, from which we obtained good agreement of relaxation time when comparing with classical results. This Hamiltonian provides a platform to study the effect of dislocation to materials' non-mechanical properties from a fundamental Hamiltonian level.

  2. Traumatic hip dislocation; a South East Nigeria hospital experience ...

    African Journals Online (AJOL)

    Background: Hip dislocation is a relatively common orthopaedic emergency. The hip is an inherently stable joint and substantial force is required for dislocation to occur. Thus hip dislocation is said to follow motor vehicle accidents with more than 90% of hip dislocations being posterior. Thompson and Epstein grade I and II ...

  3. Quantifying the effect of hydrogen on dislocation dynamics: A three-dimensional discrete dislocation dynamics framework

    Science.gov (United States)

    Gu, Yejun; El-Awady, Jaafar A.

    2018-03-01

    We present a new framework to quantify the effect of hydrogen on dislocations using large scale three-dimensional (3D) discrete dislocation dynamics (DDD) simulations. In this model, the first order elastic interaction energy associated with the hydrogen-induced volume change is accounted for. The three-dimensional stress tensor induced by hydrogen concentration, which is in equilibrium with respect to the dislocation stress field, is derived using the Eshelby inclusion model, while the hydrogen bulk diffusion is treated as a continuum process. This newly developed framework is utilized to quantify the effect of different hydrogen concentrations on the dynamics of a glide dislocation in the absence of an applied stress field as well as on the spacing between dislocations in an array of parallel edge dislocations. A shielding effect is observed for materials having a large hydrogen diffusion coefficient, with the shield effect leading to the homogenization of the shrinkage process leading to the glide loop maintaining its circular shape, as well as resulting in a decrease in dislocation separation distances in the array of parallel edge dislocations. On the other hand, for materials having a small hydrogen diffusion coefficient, the high hydrogen concentrations around the edge characters of the dislocations act to pin them. Higher stresses are required to be able to unpin the dislocations from the hydrogen clouds surrounding them. Finally, this new framework can open the door for further large scale studies on the effect of hydrogen on the different aspects of dislocation-mediated plasticity in metals. With minor modifications of the current formulations, the framework can also be extended to account for general inclusion-induced stress field in discrete dislocation dynamics simulations.

  4. Mechanisms for decoration of dislocations by small dislocation loops under cascade damage conditions

    DEFF Research Database (Denmark)

    Trinkaus, H.; Singh, B.N.; Foreman, A.J.E.

    1997-01-01

    . This effect may arise as a result of either (a) migration and enhanced agglomeration of single SIAs in the form of loops in the strain field of the dislocation or (b) glide and trapping of SIA loops (produced directly in the cascades) in the strain field of the dislocation, In the present paper, both...... of these possibilities are examined. It is shown that the strain field of the dislocation causes a SIA depletion in the compressive as well as in the dilatational region resulting in a reduced rather than enhanced agglomeration of SIAs. (SIA depletion may, however, induce enhanced vacancy agglomeration near dislocations...

  5. Dislocation nucleation facilitated by atomic segregation

    Science.gov (United States)

    Zou, Lianfeng; Yang, Chaoming; Lei, Yinkai; Zakharov, Dmitri; Wiezorek, Jörg M. K.; Su, Dong; Yin, Qiyue; Li, Jonathan; Liu, Zhenyu; Stach, Eric A.; Yang, Judith C.; Qi, Liang; Wang, Guofeng; Zhou, Guangwen

    2018-01-01

    Surface segregation--the enrichment of one element at the surface, relative to the bulk--is ubiquitous to multi-component materials. Using the example of a Cu-Au solid solution, we demonstrate that compositional variations induced by surface segregation are accompanied by misfit strain and the formation of dislocations in the subsurface region via a surface diffusion and trapping process. The resulting chemically ordered surface regions acts as an effective barrier that inhibits subsequent dislocation annihilation at free surfaces. Using dynamic, atomic-scale resolution electron microscopy observations and theory modelling, we show that the dislocations are highly active, and we delineate the specific atomic-scale mechanisms associated with their nucleation, glide, climb, and annihilation at elevated temperatures. These observations provide mechanistic detail of how dislocations nucleate and migrate at heterointerfaces in dissimilar-material systems.

  6. Dislocations in the Kitaev honeycomb model

    Science.gov (United States)

    Petrova, Olga; Tchernyshyov, Oleg

    2013-03-01

    We study the effects of introducing dislocations into the Kitaev honeycomb model. In the gapped phase, dislocations are Z2 ``twist defects'' associated with the transmutation of electric and magnetic excitations, studied previously in the context of ZN rotor models. We show that each dislocation hosts one unpaired Majorana mode. As a consequence, twist defects have the statistics of Ising anyons. Because dislocations are confined, an additional phase is accumulated due to the change in system's energy during the braiding process. This means that the result of braiding can only be defined up to a phase. Therefore, twists are said to have projective non-Abelian statistics. Research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-08ER46544.

  7. Effect of annealing temperature on the thermal stress and dislocation density of mc-Si ingot grown by DS process for solar cell application

    Science.gov (United States)

    Sanmugavel, S.; Srinivasan, M.; Aravinth, K.; Ramasamy, P.

    2018-04-01

    90% of the solar industries are using crystalline silicon. Cost wise the multi-crystalline silicon solar cells are better compared to mono crystalline silicon. But because of the presence of grain boundaries, dislocations and impurities, the efficiency of the multi-crystalline silicon solar cells is lower than that of mono crystalline silicon solar cells. By reducing the defect and dislocation we can achieve high conversion efficiency. The velocity of dislocation motion increases with stress. By annealing the grown ingot at proper temperature we can decrease the stress and dislocation. Our simulation results show that the value of stress and dislocation density is decreased by annealing the grown ingot at 1400K and the input parameters can be implemented in real system to grow a better mc-Si ingot for energy harvesting applications.

  8. Posterior atlantoaxial dislocation without odontoid fracture

    International Nuclear Information System (INIS)

    Chaudhary, Reema; Raut, Abhijit; Chaudhary, Kshitij; Metkar, Umesh; Rathod, Ashok; Sanghvi, Darshana

    2008-01-01

    We report a case of posterior atlantoaxial dislocation without a fracture of the odontoid in a 35-year-old woman. There have been nine reported cases of similar injury in the English literature. The integrity of the transverse ligament following posterior atlantoaxial dislocations has not been well documented in these reports. In the present case, MRI revealed an intact transverse ligament, which probably contributed to the stability of the C1-C2 complex following closed reduction. (orig.)

  9. Isolated Proximal Tibiofibular Dislocation during Soccer

    Directory of Open Access Journals (Sweden)

    Casey Chiu

    2015-01-01

    Full Text Available Proximal tibiofibular dislocations are rarely encountered in the Emergency Department (ED. We present a case involving a man presenting to the ED with left knee pain after making a sharp left turn on the soccer field. His physical exam was only remarkable for tenderness over the lateral fibular head. His X-rays showed subtle abnormalities of the tibiofibular joint. The dislocation was reduced and the patient was discharged from the ED with orthopedic follow-up.

  10. Dislocation of the proximal tibiofibular joint

    OpenAIRE

    Milankov Miroslav; Kecojević Vaso; Gvozdenović Nemanja; Obradović Mirko

    2013-01-01

    Introduction. Dislocation of the proximal tibiofibular joint is a rare injury. It occurs during a sports activity that includes rough twisting movements of the bent knee. The role of the proximal tibiofibular joint is to reduce torsional loads to the ankle, to distribute the bending moment of the outer side of tibia, and transfer the vertical load while standing. In the literature there is no larger series; only several cases of the proximal tibiofibular joint dislocation treated by dif...

  11. Posterior sternoclavicular dislocation: an American football injury

    DEFF Research Database (Denmark)

    Marker, L B; Klareskov, B

    1996-01-01

    Posterior dislocation of the sternoclavicular joint is uncommon, accounting for less than 0.1% of all dislocations. Since 1824 a little more than 100 cases have been reported, and the majority in the past 20 years. A review of published reports suggests that this injury is seen particularly in co...... in connection with American football. A typical case is described. The importance of this injury is that there is often a delay in diagnosis with potentially serious complications....

  12. The epidemiology of shoulder dislocations in Oslo.

    Science.gov (United States)

    Liavaag, S; Svenningsen, S; Reikerås, O; Enger, M; Fjalestad, T; Pripp, A H; Brox, J I

    2011-12-01

    There are few previous studies on the incidence of shoulder dislocation in the general population. The aim of the study was to report the incidence of acute shoulder dislocations in the capital of Norway (Oslo) in 2009. Patients of all ages living in Oslo, sustaining a dislocation of the glenohumeral joint, were identified using electronic diagnosis registers, patient protocols, radiological registers of the hospitals, and the Norwegian Patient Register (NPR). The overall incidence rate was 56.3 [95% confidence interval (CI) 50.2-62.4] per 100,000 person-years, with rates of 82.2 (95% CI 71.7-92.8) and 30.9 (95% CI 24.5-37.3) in men and women, respectively. The incidence of primary dislocations was 26.2 (95% CI 22.1-30.4). The overall incidence of shoulder dislocations in Oslo was higher than previously reported incidences. The incidence of primary dislocations was also higher than that in previously reported studies for the general population but it was close to the incidence reported in Malmø, Sweden. © 2011 John Wiley & Sons A/S.

  13. Generalized dynamics of moving dislocations in quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Agiasofitou, Eleni; Lazar, Markus [Emmy Noether Research Group, Department of Physics, Darmstadt University of Technology, Hochschulstrasse 6, D-64289 Darmstadt (Germany); Kirchner, Helmut, E-mail: agiasofitou@mechanik.tu-darmstadt.d, E-mail: lazar@mechanik.tu-darmstadt.d, E-mail: kirchnerhok@hotmail.co [INM-Leibniz Institute for New Materials, Campus D22, D-66123 Saarbruecken (Germany)

    2010-12-15

    A theoretical framework for dislocation dynamics in quasicrystals is provided according to the continuum theory of dislocations. Firstly, we present the fundamental theory for moving dislocations in quasicrystals giving the dislocation density tensors and introducing the dislocation current tensors for the phonon and phason fields, including the Bianchi identities. Next, we give the equations of motion for the incompatible elastodynamics as well as for the incompatible elasto-hydrodynamics of quasicrystals. We continue with the derivation of the balance law of pseudomomentum thereby obtaining the generalized forms of the Eshelby stress tensor, the pseudomomentum vector, the dynamical Peach-Koehler force density and the Cherepanov force density for quasicrystals. The form of the dynamical Peach-Koehler force for a straight dislocation is obtained as well. Moreover, we deduce the balance law of energy that gives rise to the generalized forms of the field intensity vector and the elastic power density of quasicrystals. The above balance laws are produced for both models. The differences between the two models and their consequences are revealed. The influences of the phason fields as well as of the dynamical terms are also discussed.

  14. High Resolution Topography Analysis on Threading Edge Dislocations in 4H-SiC Epilayers

    International Nuclear Information System (INIS)

    Kamata, I.; Nagano, M.; Tsuchida, H.; Chen, Y.; Dudley, M.

    2009-01-01

    Threading edge dislocations (TEDs) in a 4H-SiC epitaxial layer are investigated using high-resolution synchrotron topography. Six types of TED image are confirmed to correspond to the Burgers vector directions by a comparison of computer simulated images and observed topography images in crystal boundaries. Using a mapping method, a wide spatial distribution of the six types of TED is examined in a quarter section of a 2-inch wafer.

  15. First combined electron backscatter diffraction and transmission electron microscopy study of grain boundary structure of deformed quartzite.

    Science.gov (United States)

    Shigematsu, N; Prior, D J; Wheeler, J

    2006-12-01

    The structures of boundaries in a deformed and dynamically recovered and recrystallized quartz polycrystal (mylonite) were characterized by transmission electron microscopy, after the misorientation angles across the same grain boundaries had been analysed using electron backscatter diffraction in a scanning electron microscope. In this new approach, a specific sample area is mapped with electron backscatter diffraction, and the mapped area is then attached to a foil, and by the ion beam thinned for transmission electron microscopy analysis. Dislocations in grain boundaries were recognized as periodic and parallel fringes. The fringes associated with dislocations are observed in boundaries with misorientations less than 9 degrees , whereas such fringes cannot be seen in the boundaries with misorientations larger than 17 degrees . Some boundaries with misorientations between 9 degrees and 17 degrees generally have no structures associated with dislocation. One segment of a boundary with a misorientation of 13.5 degrees has structures associated with dislocations. It is likely that the transition from low-angle to high-angle boundaries occurs at misorientations ranging from approximately 9 degrees to 14 degrees . Change in the grain boundary structure presumably influences the mobility of the boundaries. In the studied deformed quartz vein, a relative dearth of boundaries between misorientation angles of theta = 2 degrees and theta = 15 degrees has previously been reported, and high-angle boundaries form cusps where they intersect low-angle boundaries, suggesting substantial mobility of high-angle boundaries.

  16. 78 FR 52135 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental To...

    Science.gov (United States)

    2013-08-22

    ...--Marine Mammal Density Estimates Density Species (animals/km \\2\\) Bottlenose dolphin \\1\\ 0.455 Atlantic... criteria and thresholds in a final rule on the unintentional taking of marine animals occurring incidental... analysis assumed the marine species populations were 100 percent small animals. The criterion with the...

  17. 77 FR 65059 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2012-10-24

    ... harassment, small numbers of nine species of marine mammals incidental to in-ice marine seismic surveys in..., by harassment, from ION's in-ice seismic survey will have a negligible impacton the affected species... whales and other marine mammal species in the Beaufort and Chukchi Seas during ION's in-ice seismic...

  18. 76 FR 62378 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2011-10-07

    ....noaa.gov/publications/tm/tm210/ . The West Indian manatee (Trichechus manatus) is managed by the U.S... populations of marine mammals that are expected to be present in the action area. The Incidental Take... mammal populations; (iii) results of the monitoring program, including numbers by species/stock of any...

  19. 77 FR 72327 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2012-12-05

    ... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XC283 Takes of...), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice; issuance of an incidental... State Parks). Once a particular study has ended, the respective sampling equipment is removed. No trash...

  20. Dislocation Dynamics in Al-Li Alloys. Mean Jump Distance and Activation Length of Moving Dislocations

    NARCIS (Netherlands)

    Hosson, J.Th.M. De; Huis in 't Veld, A.; Tamler, H.; Kanert, O.

    1984-01-01

    Pulsed nuclear magnetic resonance proved to be a complementary new technique for the study of moving dislocations in Al-Li alloys. The NMR technique, in combination with transmission electron microscopy and strain-rate change experiments have been applied to study dislocation motion in Al-2.2 wt% Li

  1. Evaluation of traumatic atlantooccipital dislocations.

    Science.gov (United States)

    Lee, C; Woodring, J H; Goldstein, S J; Daniel, T L; Young, A B; Tibbs, P A

    1987-01-01

    The diagnosis of traumatic atlantooccipital dislocation (AOD) from the cross-table lateral radiograph is difficult because of problems in demonstrating the complex anatomy of this area and the intricate radiographic methods used to diagnose AOD. Although CT or polytomography seem to be the most accurate diagnostic methods, it is often the lateral radiograph from which the diagnosis and further decisions are made. To determine both the best radiographic method for diagnosing AOD from the lateral radiograph and the role of CT and tomography in the diagnosis of AOD, the literature was reviewed concerning how the diagnosis of AOD has been obtained. In addition, the Wholey dens-basion line, the Powers ratio, the Dublin method of diagnosing AOD, and measurement of the atlantooccipital joint width were applied to 12 cases of traumatic AOD; and the Wholey dens-basion line and the Powers ratio were determined in 100 normal adults and 50 normal children. An alternative plain radiographic method for diagnosing AOD was developed, called the X-line method. This was the most accurate of the methods tested, correctly diagnosing AOD in 75% of cases. The Wholey dens-basion line and direct measurement of the atlantooccipital joint width were each correct in 50% of cases, the Powers ratio in 33% of cases, and the Dublin method in only 25% of cases. Ultimately, either CT or polytomography should provide the definitive diagnosis. In this regard high-resolution CT with reformatted coronal and sagittal images generated from 2-mm thin axial slices appeared to have the most promise as the first study of choice.

  2. An Incidentally Detected Right Ventricular Pseudoaneurysm

    Directory of Open Access Journals (Sweden)

    Vamsi C. Gaddipati

    2017-01-01

    Full Text Available Ventricular pseudoaneurysm is an uncommon, potentially fatal complication that has been associated with myocardial infarction, cardiac surgery, chest trauma, and infectious processes. Diagnosis can be challenging, as cases are rare and slowly progressing and typically lack identifiable features on clinical presentation. As a result, advanced imaging techniques have become the hallmark of identification. Ahead, we describe a patient who presents with acute decompensated heart failure and was incidentally discovered to have a large right ventricular pseudoaneurysm that developed following previous traumatic anterior rib fracture.

  3. Private Arbitration of Incidental Public Law Issues

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2009-01-01

     The article discusses the incidental public law issues which can arise in an arbitration case, e.g. concerning power, heating, natural gas and other public facility legislation, national or Community legal restrictive trade practices law, and rules on state administration approval of the terms...... by arbitration, and where the award is nullifiable only if its findings are in violation of public policy, the ordre public. The article relies on UNCITRAL's Model Arbitration Law, the new Danish arbitration act (DAA), national European case law, and literature and case law of the European Court....

  4. Interaction of slip with grain boundary in the Li2 ordered structure - A Σ = 9 tilt boundary

    International Nuclear Information System (INIS)

    Yoo, M.H.; King, A.H.

    1988-01-01

    The role of slip/grain boundary interaction in intergranular fracture has been analyzed for a Σ = 9 tilt boundary in Li 2 ordered alloys by use of the anisotropic elasticity theory of dislocations and fracture. Screw superpartials cross slip easily at the boundary onto the (1 bar 11) and the (001) planes for low and high temperatures, respectively. Transmission of primary slip dislocations onto the conjugate slip system occurs with some difficulty, which is eased by localized disordering. Unless a symmetric double pile-up occurs simultaneously, cleavage fracture is predicted to occur on the (bar 1 11) plane, not intergranular fracture. Absorption (or emission ) of superpartials occurs only when the boundary region is disordered. The inherent weakness of grain boundaries in Ni 3 Al and its improvement by boron segregation are discussed

  5. Hybrid Dislocated Control and General Hybrid Projective Dislocated Synchronization for Memristor Chaotic Oscillator System

    Directory of Open Access Journals (Sweden)

    Junwei Sun

    2014-01-01

    Full Text Available Some important dynamical properties of the memristor chaotic oscillator system have been studied in the paper. A novel hybrid dislocated control method and a general hybrid projective dislocated synchronization scheme have been realized for memristor chaotic oscillator system. The paper firstly presents hybrid dislocated control method for stabilizing chaos to the unstable equilibrium point. Based on the Lyapunov stability theorem, general hybrid projective dislocated synchronization has been studied for the drive memristor chaotic oscillator system and the same response memristor chaotic oscillator system. For the different dimensions, the memristor chaotic oscillator system and the other chaotic system have realized general hybrid projective dislocated synchronization. Numerical simulations are given to show the effectiveness of these methods.

  6. The Effects of Training on Caregiver Implementation of Incidental Teaching

    Science.gov (United States)

    Hsieh, Hsing-Hsiu; Wilder, David A.; Abellon, O. Elizabeth

    2011-01-01

    A brief training package consisting of modeling, rehearsal, and feedback was evaluated to train caregivers to use incidental teaching to teach 3 children with autism to request an item or activity. The training package improved correct implementation of the incidental teaching procedure by caregivers. In addition, probes indicated that caregivers…

  7. Incidental Exposure and L3 Learning of Morphosyntax

    Science.gov (United States)

    Grey, Sarah; Williams, John N.; Rebuschat, Patrick

    2014-01-01

    Evidence of learning following incidental exposure has been found for aspects of nonnative syntax in adults (Rebuschat & Williams, 2006, 2012; Williams & Kuribara, 2008). However, little research has tested delayed effects of learning under an incidental condition or moved beyond word order. This study investigated learning of third…

  8. Isolated dorsal dislocation of the tarsal naviculum

    Directory of Open Access Journals (Sweden)

    Kaziz Hamdi

    2015-01-01

    Full Text Available Isolated dislocation of the tarsal naviculum is an unusual injury, scarcely reported in the literature. The naviculum is surrounded by the rigid bony and ligamentous support hence fracture dislocation is more common than isolated dislocation. The mechanism and treatment options remain unclear. In this case report, we describe a 31 year old man who sustained an isolated dorsal dislocation of the left tarsal naviculum, without fracture, when he was involved in a motor vehicle collision. The reported mechanism of the dislocation is a hyper plantar flexion force applied to the midfoot, resulting in a transient disruption of the ligamentous support of the naviculum bone, with dorsal displacement of the bone. The patient was treated with open reduction and Krischner-wire fixation of the navicular after the failure of closed reduction. The wires were removed after 6 weeks postoperatively. Physiotherapy for stiffness and midfoot pain was recommended for 2 months. At 6 months postoperatively, limping, midfoot pain and weakness were reported, no X-ray abnormalities were found. The patient returned to his obvious activities with a normal range of motion.

  9. Isolated dorsal dislocation of the tarsal naviculum.

    Science.gov (United States)

    Hamdi, Kaziz; Hazem, Ben Ghozlen; Yadh, Zitoun; Faouzi, Abid

    2015-01-01

    Isolated dislocation of the tarsal naviculum is an unusual injury, scarcely reported in the literature. The naviculum is surrounded by the rigid bony and ligamentous support hence fracture dislocation is more common than isolated dislocation. The mechanism and treatment options remain unclear. In this case report, we describe a 31 year old man who sustained an isolated dorsal dislocation of the left tarsal naviculum, without fracture, when he was involved in a motor vehicle collision. The reported mechanism of the dislocation is a hyper plantar flexion force applied to the midfoot, resulting in a transient disruption of the ligamentous support of the naviculum bone, with dorsal displacement of the bone. The patient was treated with open reduction and Krischner-wire fixation of the navicular after the failure of closed reduction. The wires were removed after 6 weeks postoperatively. Physiotherapy for stiffness and midfoot pain was recommended for 2 months. At 6 months postoperatively, limping, midfoot pain and weakness were reported, no X-ray abnormalities were found. The patient returned to his obvious activities with a normal range of motion.

  10. 76 FR 41463 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a...

    Science.gov (United States)

    2011-07-14

    ... requirements, many marine animals may need to remain in areas where they are exposed to chronic stimuli... Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine... Atmospheric Administration (NOAA), National Marine Fisheries Service (NMFS). ACTION: Notice; proposed...

  11. Rare Inferior Shoulder Dislocation (Luxatio Erecta)

    Science.gov (United States)

    Cift, Hakan; Soylemez, Salih; Demiroglu, Murat; Ozkan, Korhan; Ozden, Vahit Emre; Ozkut, Afsar T.

    2015-01-01

    Although shoulder dislocations have been seen very frequently, inferior dislocation of shoulder constitutes only 0.5% of all shoulder dislocations. We share our 4 patients with luxatio erecta and present their last clinical control. 2 male and 2 female Caucasian patients were diagnosed as luxatio erecta. Patients' ages were 78, 62, 65, and 76. All patients' reduction was done by traction-abduction and contour traction maneuver in the operating room. The patients had no symptoms and no limitation of range of motion of their shoulder at their last control. Luxatio erecta is seen rarely, and these patients may have neurovascular injury. These patients should be carefully examined and treated by the orthopaedic and traumatology surgeons. PMID:25883820

  12. Rare Inferior Shoulder Dislocation (Luxatio Erecta

    Directory of Open Access Journals (Sweden)

    Hakan Cift

    2015-01-01

    Full Text Available Although shoulder dislocations have been seen very frequently, inferior dislocation of shoulder constitutes only 0.5% of all shoulder dislocations. We share our 4 patients with luxatio erecta and present their last clinical control. 2 male and 2 female Caucasian patients were diagnosed as luxatio erecta. Patients’ ages were 78, 62, 65, and 76. All patients’ reduction was done by traction-abduction and contour traction maneuver in the operating room. The patients had no symptoms and no limitation of range of motion of their shoulder at their last control. Luxatio erecta is seen rarely, and these patients may have neurovascular injury. These patients should be carefully examined and treated by the orthopaedic and traumatology surgeons.

  13. Void growth suppression by dislocation impurity atmospheres

    International Nuclear Information System (INIS)

    Weertman, J.; Green, W.V.

    1976-01-01

    A detailed calculation is given of the effect of an impurity atmosphere on void growth under irradiation damage conditions. Norris has proposed that such an atmosphere can suppress void growth. The hydrostatic stress field of a dislocation that is surrounded by an impurity atmosphere was found and used to calculate the change in the effective radius of a dislocation line as a sink for interstitials and vacancies. The calculation of the impurity concentration in a Cottrell cloud takes into account the change in hydrostatic pressure produced by the presence of the cloud itself. It is found that void growth is eliminated whenever dislocations are surrounded by a condensed atmosphere of either oversized substitutional impurity atoms or interstitial impurity atoms. A condensed atmosphere will form whenever the average impurity concentration is larger than a critical concentration

  14. Simulation of thermally activated dislocation glide

    International Nuclear Information System (INIS)

    Roennpagel, D.; Mohles, V.

    1994-01-01

    Solid solution hardening was investigated by simulating the motion of a flexible dislocation in thermal equilibrium while overcoming obstacles by thermal activation. In a first approach, the waiting times before activation were analysed at several temperatures, external stresses and segment lengths. From statistical studies of such activation event, the effective attack frequency, Gibb's free enthalpy of activation and the activation volume were derived in strict analogy to the analysis of experimental data. As a second approach the average velocity of a dislocation gliding over an infinite row of equidistant obstacles was calculated by simulation. The temperature dependence of this speed significantly differs from that of the waiting times, indicating that kinetic effects must not be neglected even at high at high temperatures where dislocation motion is said to be 'overdamped'. (au)

  15. Dislocation microstructure evolution in cyclically twisted microsamples: a discrete dislocation dynamics simulation

    International Nuclear Information System (INIS)

    Senger, J; Weygand, D; Kraft, O; Gumbsch, P

    2011-01-01

    Miniaturization in technical devices has increased interest in the investigation of the deformation and fatigue behaviour of metals in the micrometre regime. Due to the small dimensions of these devices, mechanical properties depend on the motion of a marginal number of dislocations. In this paper, the evolution of dislocation microstructure in torsion loaded single crystalline aluminium wires is analysed by three-dimensional discrete dislocation dynamics simulations. It is shown that the size of pile-ups and the number of the active slip systems is significantly influenced by cross-slip events independent of the crystallographic orientation. Dislocations are driven by the stress gradient from the applied loading to move into the centre of the sample. These dislocations cannot escape through the surface because of the reversal of the sign of the stress in the centre of the sample. If the micrometre-sized specimens are untwisted, the remaining dislocation microstructure in these samples depends on the maximum torsion angle reached before unloading. The larger the torsion angle, the higher is the remaining dislocation density in the unloaded specimens. These results are discussed with respect to cyclic deformation mechanisms at small scale

  16. Positron trapping at dislocations in metals

    International Nuclear Information System (INIS)

    Bergersen, B.; McMullen, T.

    1977-01-01

    The trapping rate of positrons at dislocations in metals, and its temperature dependence, are calculated. Two different trapping processes, with the excess energy absorbed in either electron-hole pair formation or by phonon creation, are considered and the former is found to be the most important. An extension of the theory to include depletion of the positron density around the dislocations in a diffusion approximation is included. The trapping is found to be transition limited if the temperature is low or the trap potential shallow. At room temperature diffusion is important for deep traps. (author)

  17. Dislocation-mediated strain hardening in tungsten: Thermo-mechanical plasticity theory and experimental validation

    Science.gov (United States)

    Terentyev, Dmitry; Xiao, Xiazi; Dubinko, A.; Bakaeva, A.; Duan, Huiling

    2015-12-01

    A self-consistent thermo-mechanical model to study the strain-hardening behavior of polycrystalline tungsten was developed and validated by a dedicated experimental route. Dislocation-dislocation multiplication and storage, as well dislocation-grain boundary (GB) pinning were the major mechanisms underlying the evolution of plastic deformation, thus providing a link between the strain hardening behavior and material's microstructure. The microstructure of the polycrystalline tungsten samples has been thoroughly investigated by scanning and electron microscopy. The model was applied to compute stress-strain loading curves of commercial tungsten grades, in the as-received and as-annealed states, in the temperature range of 500-1000 °C. Fitting the model to the independent experimental results obtained using a single crystal and as-received polycrystalline tungsten, the model demonstrated its capability to predict the deformation behavior of as-annealed samples in a wide temperature range and applied strain. The relevance of the dislocation-mediated plasticity mechanisms used in the model have been validated using transmission electron microscopy examination of the samples deformed up to different amounts of strain. On the basis of the experimental validation, the limitations of the model are determined and discussed.

  18. Negotiating boundaries

    DEFF Research Database (Denmark)

    Aarhus, Rikke; Ballegaard, Stinne Aaløkke

    2010-01-01

    to maintain the order of the home when managing disease and adopting new healthcare technology. In our analysis we relate this boundary work to two continuums of visibility-invisibility and integration-segmentation in disease management. We explore five factors that affect the boundary work: objects......To move treatment successfully from the hospital to that of technology assisted self-care at home, it is vital in the design of such technologies to understand the setting in which the health IT should be used. Based on qualitative studies we find that people engage in elaborate boundary work......, activities, places, character of disease, and collaboration. Furthermore, the processes are explored of how boundary objects move between social worlds pushing and shaping boundaries. From this we discuss design implications for future healthcare technologies for the home....

  19. Boundary Spanning

    DEFF Research Database (Denmark)

    Zølner, Mette

    The paper explores how locals span boundaries between corporate and local levels. The aim is to better comprehend potentialities and challenges when MNCs draws on locals’ culture specific knowledge. The study is based on an in-depth, interpretive case study of boundary spanning by local actors...... in the period of post-acquisition when their organization is being integrated into the acquiring MNC. The paper contributes to the literature on boundary spanning in three ways: First, by illustrating that boundary spanning is performed by numerous organizational actors in a variety of positions in MNCs......, inclusively by locals in subsidiaries. Second, by showing that boundary spanning is ‘situated’ in the sense that its result depends on the kind of knowledge to be transmitted and the attitude of the receivers. A third contribution is methodological. The study illustrates that combining bottom-up grounded...

  20. Ipsilateral open anterior hip dislocation and open posterior elbow dislocation in an adult

    Directory of Open Access Journals (Sweden)

    Kumar Sunil

    2014-02-01

    Full Text Available 【Abstract】Open anterior dislocation of the hip is a very rare injury, especially in adults. It is a hyperabduction, external rotation and extension injury. Its combination with open posterior dislocation of the elbow has not been described in English language-based medical literature. Primary resuscitation, debridement, urgent reduction of dislocation, and adequate antibiotic support resulted in good clinical outcome in our patient. At 18 months follow-up, no signs of avascular necrosis of the femoral head or infection were observed.

  1. A phase-field simulation study of irregular grain boundary migration during recrystallization

    DEFF Research Database (Denmark)

    Moelans, N.; Zhang, Yubin; Godfrey, A.

    2015-01-01

    We present simulation results based on a phase-field model that describes the migration of recrystallization boundaries into spatially varying deformation energy fields. Energy fields with 2-dimensional variations representing 2 sets of dislocation boundaries lying at equal, but opposite, angles...... in recrystallization experiments. They give new insights in the way deformation microstructures can affect the migration behavior of recrystallization boundaries and can lead to a stop-and-go type of migration of the recrystallization boundary even in pure materials....

  2. Incidental emotions influence risk preference and outcome evaluation.

    Science.gov (United States)

    Zhao, Ding; Gu, Ruolei; Tang, Ping; Yang, Qiwei; Luo, Yue-Jia

    2016-10-01

    Incidental emotions, which are irrelevant to the current decision, play a significant role in the decision-making process. In this study, to investigate the influence of incidental emotions on behavioral, psychological, and electrophysiological responses in the process of decision making, participants were required to perform a monetary gambling task. During the selection stage, an emotional picture, which was chosen from the Chinese Affective Picture System and fell into one of three categories: negative, neutral, and positive, was presented between two alternatives (small/large amount of bet). The pictures were provided to induce incidental emotions. ERPs and self-rating emotional experiences to outcome feedback were recorded during the task. Behavioral results showed that positive incidental emotions elicited risk preference, but emotional experiences to outcome feedback were not influenced by incidental emotions. The feedback-related negativity amplitudes were larger in the positive emotion condition than in the negative and neutral emotion conditions for small outcomes (including wins and losses), whereas there was no difference between the three conditions for large outcomes. In addition, the amplitudes of P3 were reduced overall in the negative emotion condition. We suggest that incidental emotions have modulated both the option assessment stage (manifested in behavioral choices) and the outcome evaluation stage (manifested in ERP amplitudes) of decision making unconsciously (indicated by unchanged subjective emotional experiences). The current findings have expanded our understanding of the role of incidental emotion in decision making. © 2016 Society for Psychophysiological Research.

  3. Clinical Treatment of Chronic Condylar Dislocation by Restoring Anterior Guidance

    OpenAIRE

    澤田, 宏二; 荒井, 良明; メディナ, ラウル; 河野, 正司; 福井, 忠雄; 花田, 晃治; Sawada, Koji; Arai, Yoshiaki; Medina, Raul; Kohno, Shoji; Fukui, Tadao; Hanada, Kooji

    1997-01-01

    The mechanism of condylar dislocation is not exactly understood. Temporomandibular (TMJ) surgery is a common option in the treatment of chronic condylar dislocation, but some authors have reported disappearance of its symptomatology after occlusal treatment. A case in which condylar dislocation disappeared by changing the location of anterior guidance is presented. The patient was an 18 year-old male with an Angle class Ⅲ malocclusion who had been suffering from condylar dislocation of the ri...

  4. Incidental bony pathology when reporting trauma orthopantomograms

    Energy Technology Data Exchange (ETDEWEB)

    Macanovic, M., E-mail: mladenmaca@gmail.co [Derriford Hospital NHS Trust, Plymouth (United Kingdom); Gangidi, S.; Porter, G.; Brown, S.; Courtney, D. [Derriford Hospital NHS Trust, Plymouth (United Kingdom); Porter, J. [Community Dental Service, Plymouth Primary Care Trust, Plymouth, Devon (United Kingdom)

    2010-10-15

    Radiologists frequently report orthopantomograms (OPTs) and other views of the mandible, most often in patients who have suffered facial trauma. These examinations may reveal incidental pathology. It is important that radiologists are aware of the radiological appearances and the clinical significance of these lesions. In this review we will present examples of the more common odontogenic lesions including: radicular cyst, odontogenic keratocyst, dentigerous cyst, ameloblastoma, and also examples of non-odontogenic pathology: bisphosphonate-related osteonecrosis of the jaw (BRONJ) and chronic osteomyelitis. Although some of the lesions will require computed tomography (CT) or magnetic resonance imaging (MRI) for further lesion characterization and evaluation of the surrounding tissues, we are going to focus on the plain film appearances. We will also briefly discuss the pathogenesis, epidemiology, and treatment of these lesions.

  5. Electron-dislocation interaction at low temperatures. Progress report

    International Nuclear Information System (INIS)

    1978-01-01

    The interaction of mobile dislocations with electrons in copper and copper alloys has shown that dislocation motion in copper, at low temperature, can be treated as an analog of an underdamped oscillator. We have also shown that the viscous drag on mobile dislocations in type II superconductors can be treated as an acoustic attenuation of an elastic wave

  6. A case of posterior shoulder dislocation with ipsilateral humeral ...

    African Journals Online (AJOL)

    A case of posterior shoulder dislocation with ipsilateral humeral shaft fracture. P Sharma, S Meena, D Rastogi, B Chowdhury. Abstract. Posterior shoulder dislocations are rare and represent 2–5% of all traumatic shoulder dislocation. A combination of this injury with ipsilateral humeral shaft fracture is extremely rare event.

  7. Nanoscale dislocation shear loops at static equilibrium and finite temperature

    Science.gov (United States)

    Dang, Khanh; Capolungo, Laurent; Spearot, Douglas E.

    2017-12-01

    Atomistic simulations are used to determine the resolved shear stress necessary for equilibrium and the resulting geometry of nanoscale dislocation shear loops in Al. Dislocation loops with different sizes and shapes are created via superposition of elemental triangular dislocation displacement fields in the presence of an externally imposed shear stress. First, a bisection algorithm is developed to determine systematically the resolved shear stress necessary for equilibrium at 0 K. This approach allows for the identification of dislocation core structure and a correlation between dislocation loop size, shape and the computed shear stress for equilibrium. It is found, in agreement with predictions made by Scattergood and Bacon, that the equilibrium shape of a dislocation loop becomes more circular with increasing loop size. Second, the bisection algorithm is extended to study the influence of temperature on the resolved shear stress necessary for stability. An approach is presented to compute the effective lattice friction stress, including temperature dependence, for dislocation loops in Al. The temperature dependence of the effective lattice friction stress can be reliably computed for dislocation loops larger than 16.2 nm. However, for dislocation loops smaller than this threshold, the effective lattice friction stress shows a dislocation loop size dependence caused by significant overlap of the stress fields on the interior of the dislocation loops. Combined, static and finite temperature atomistic simulations provide essential data to parameterize discrete dislocation dynamics simulations.

  8. An irreducible ankle fracture dislocation: the Bosworth injury

    NARCIS (Netherlands)

    Schepers, Tim; Hagenaars, Tjebbe; den Hartog, Dennis

    2012-01-01

    Irreducible fracture dislocations of the ankle are rare and represent true orthopedic emergencies. We present a case of a fracture dislocation that was irreducible owing to a fixed dislocation of the proximal fibular fragment posterior to the lateral ridge of the tibia. This particular type of

  9. Monteggia fracture-dislocation: a case report, its' initial management ...

    African Journals Online (AJOL)

    This is a report and description of initial management of a fracture- dislocation, which was consequent to a sideswipe injury and consisted of a combination of the following injuries; lateral dislocation of the radial head, fractures of the olecranon and proximal ulna in the left forearm. The radial head dislocation and fracture of ...

  10. An Irreducible Ankle Fracture Dislocation: The Bosworth Injury

    NARCIS (Netherlands)

    T. Schepers (Tim); T. Hagenaars (Tjebbe); D. den Hartog (Dennis)

    2012-01-01

    textabstractIrreducible fracture dislocations of the ankle are rare and represent true orthopedic emergencies. We present a case of a fracture dislocation that was irreducible owing to a fixed dislocation of the proximal fibular fragment posterior to the lateral ridge of the tibia. This particular

  11. Lack of experience is a significant factor in the missed diagnosis of perilunate fracture dislocation or isolated dislocation

    Directory of Open Access Journals (Sweden)

    Ilker Çolak

    2018-01-01

    Conclusion: The results of this study indicated that lack of experience was the most important factor in the misdiagnosis of perilunate fracture dislocation or isolated dislocation. Level of Evidence: Level IV, diagnostic study.

  12. Kinetics of interstitial segregation in Cottrell atmospheres and grain boundaries

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Jiří; Zickler, G. A.; Kozeschnik, E.; Fischer, F. D.

    2015-01-01

    Roč. 95, č. 9 (2015), s. 458-465 ISSN 0950-0839 R&D Projects: GA ČR(CZ) GA15-06390S Institutional support: RVO:68081723 Keywords : segregation * grain boundaries * dislocations * simulation * thermodynamic extremal principle Subject RIV: BJ - Thermodynamics Impact factor: 0.918, year: 2015

  13. Simulations of boundary migration during recrystallization using molecular dynamics

    DEFF Research Database (Denmark)

    Godiksen, Rasmus Brauner; Trautt, Z.T.; Upmanyu, M.

    2007-01-01

    process is not uniform as assumed in many recrystallization models, but that the grain boundaries migrate in an irregular fashion and exhibit a strong dependence on the local presence of dislocations, which can distort the local migration process significantly. (c) 2007 Acta Materialia Inc. Published...

  14. Slip transfer across grain boundaries in Fe-Si bicrystals

    Czech Academy of Sciences Publication Activity Database

    Gemperlová, Juliana; Polcarová, Milena; Gemperle, Antonín; Zárubová, Niva

    2004-01-01

    Roč. 378, - (2004), s. 97-101 ISSN 0925-8388 R&D Projects: GA ČR GA202/01/0670 Institutional research plan: CEZ:AV0Z1010914 Keywords : metals * dislocations and disclinations * bicrystals * grain boundaries * transmission electron microscopy * X-ray diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.562, year: 2004

  15. Screening for congenital dislocation of the hip

    International Nuclear Information System (INIS)

    Fendel, H.

    1987-01-01

    Although the prevalence of (idiopathic) congenital dislocation of the hip (CDH) within the Member States of the European Community is not exactly known, it must be considered as a major problem of public health care and protection. By assessment of available data one can assume that between 1 and 2% of all newborns have dislocation or instability of one or both hips. There is a female predominance of 4:1 and some risk factors are known. The reasons of a higher prevalence in some areas are not yet well understood. Most of instable hips will spontaneously become stable within the first days or weeks of life. However, a considerable number of infants (less than 1%) will remain with instable hips which may dislocate. Dislocation either present at birth or as a result of persistent instability leads to subsequent hip deformation. This is a serious event for each affected individual, and is a heavy load on health care and social costs for the public. Treatment of CDH is easy and usually effective when started early, i.e. before the fourth month of life. The earlier treatment is started the easier, shorter, safer and less expensive it is and its impairment on child development and mother-child interaction can be held to a minimum. Screening for CDH is therefore the most important part of health protection in early infancy. However, this paper concludes that neither sonography nor X-ray examinations are appropriate for CDH screening

  16. managing temporomandibular joint dislocation in ibadan

    African Journals Online (AJOL)

    manoeuvre and IMF. Fifty percent of the chronic cases were successfully managed with the Hippocrates manoeuvre. Follow up was < 2 weeks in 7 of the cases. ... in the above named hospital was anterior dislocation, the female gender predominance, ... also presented very early probably due to an awareness of where to ...

  17. stabilisation of posterior sternoclavicular joint dislocation using

    African Journals Online (AJOL)

    A case is reported where palmaris longus tendon was used to stabilise the joint following open reduction. INTRODUCTION. Posterior Sternoclavicular joint dislocation is a relatively rare injury and is reported to have been first documented by Sir Astley Cooper in 1824 (1, 2). It is a potentially life threatening injury due to the ...

  18. Tendoscopic treatment of recurrent peroneal tendon dislocation

    NARCIS (Netherlands)

    Scholten, Peter E.; Breugem, Stefan J. M.; van Dijk, C. Niek

    2013-01-01

    To study the possibility of tendoscopic treatment of recurrent peroneal tendon dislocation. The case of one patient is described including the tendoscopic technique to deepen the fibular groove. In this single case, there were no complications, recovery time was short, and there was no recurrence of

  19. An isolated cuboid dislocation. A case report

    Directory of Open Access Journals (Sweden)

    K. Sheahan

    2017-01-01

    Conclusion: Our take home message from this case report is that cuboid dislocations are rare injuries and are important to be aware of in reviewing X-rays in the E.D. Particularly in patients with inversion and plantar flexion type injuries to their foot and ankle joint, with an inability to weight bear and lateral midfoot pain following their injury.

  20. Ab initio phonon scattering by dislocations

    Science.gov (United States)

    Wang, Tao; Carrete, Jesús; van Roekeghem, Ambroise; Mingo, Natalio; Madsen, Georg K. H.

    2017-06-01

    Heat management in thermoelectric and power devices as well as in random access memories poses a grand challenge and can make the difference between a working and an abandoned device design. Despite the prevalence of dislocations in all these technologies, the modeling of their thermal resistance is based on 50-year-old analytical approximations, whose simplicity was driven by practical limitations rather than physical insight. We introduce an efficient ab initio approach based on Green's functions computed by two-dimensional reciprocal space integration. By combining elasticity theory and density functional theory, we calculate the scattering strength of a 90∘ misfit edge dislocation in Si. Because of the breakdown of the Born approximation, earlier literature models fail, even qualitatively. We find that a dislocation density larger than 109cm-2 is necessary to substantially influence thermal conductivity at room temperature and above. We quantify how much of the reduction of thermal conductivity measured in nanograined samples can be explained by realistic dislocation concentrations.

  1. Missed isolated volar dislocation of the scaphoid

    DEFF Research Database (Denmark)

    Kolby, Lise; Larsen, Søren; Jørring, Stig

    2007-01-01

    A patient presented with volar dislocation of the scaphoid, the diagnosis of which had been missed for two weeks. He was treated with open reduction through a combined volar and dorsal approach with decompression of the median nerve, internal fixation, and a cast for eight weeks. One year postope...... postoperatively the functional result was good. A radiograph showed no sign of avascular necrosis....

  2. Left Dislocation: a typological overview | Westbury | Stellenbosch ...

    African Journals Online (AJOL)

    The Left Dislocation construction is a typologically universal phenomenon that has received detailed analysis, from both formal and functional perspectives, in a number of genetically and areally diverse languages. The present paper aims to provide a general overview of this cross-linguistic research with a concentration ...

  3. Completion of a Dislocated Metric Space

    Directory of Open Access Journals (Sweden)

    P. Sumati Kumari

    2015-01-01

    Full Text Available We provide a construction for the completion of a dislocated metric space (abbreviated d-metric space; we also prove that the completion of the metric associated with a d-metric coincides with the metric associated with the completion of the d-metric.

  4. Dislocation Microstructures in Fatiqued Copper Polycrystals

    DEFF Research Database (Denmark)

    Winter, A.T.; Pedersen, Ole Bøcker; Rasmussen, K.V.

    1981-01-01

    Dislocation structures characteristic of persistent slip bands were observed in the interior of polycrystalline copper after fatigue. At low strain amplitudes, within the plateau on the cyclic stress-strain curve, only structures identical to those seen in single crystals were observed. This allows...

  5. Tailoring surgical management of dislocated clavicle fractures

    NARCIS (Netherlands)

    Wijdicks, F.J.G.

    2013-01-01

    In this thesis literature research and clinical studies are presented to assist physicians in the decision making process for surgical treatment of dislocated midshaft clavicle fractures (DMCF). In Chapter 1 an introduction is given regarding the background, aim and outline of this thesis. Chapter 2

  6. Computed tomography of traumatic atlantooccipital dislocation.

    Science.gov (United States)

    Gerlock, A J; Mirfakhraee, M; Benzel, E C

    1983-09-01

    Although atlantooccipital dislocation is a well-recognized radiological entity, its computed tomographic (CT) recognition has not been previously described. It is the purpose of this report to show the complementary role of CT in precisely defining the abnormalities in both the coronal and the sagittal reconstruction planes. A case is presented and the literature is reviewed.

  7. Cruciate paralysis secondary to traumatic atlantooccipital dislocation.

    Science.gov (United States)

    Sweet, Jennifer; Ammerman, Joshua; Deshmukh, Vivek; White, Joseph

    2010-01-01

    Cruciate paralysis is a clinical phenomenon thought to result from injury to decussating pyramidal tract fibers at the cervicomedullary junction, producing clinical findings of upper-extremity weakness out of proportion to the lower extremities. The authors present, to their knowledge, the first reported case of cruciate paralysis resulting from atlantooccipital dislocation.

  8. Incidental Reflector Comparison of Containerized Dry Fire Extinguishing Agents

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Bryan Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wysong, Andrew Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-14

    This document addresses the incidental reflector reactivity worth of containerized fire extinguishing agents authorized for use in PF-4 at Los Alamos National Laboratory (LANL). The intent of the document is to analyze dry fire extinguishing agent that remains in a container and is not actively being used in a fire emergency. The incidental reflector reactivity worth is determined by comparison to various thicknesses of close fitting water reflection which is commonly used to bound incidental reflectors in criticality safety evaluations. The conclusion is that even in unlimited quantities, when containerized the authorized dry fire extinguishing agents are bound by 0.4 inches of close fitting water.

  9. Interaction of 〈1 0 0〉 dislocation loops with dislocations studied by dislocation dynamics in α-iron

    Energy Technology Data Exchange (ETDEWEB)

    Shi, X.J.; Dupuy, L. [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette (France); Devincre, B. [Laboratoire d’Etude des Microstructures, CNRS-ONERA, 29 av. de la Division Leclerc, 92322 Châtillon Cedex (France); Terentyev, D. [SCK–CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium); Vincent, L. [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette (France)

    2015-05-15

    Highlights: • Interactions between edge dislocations and radiation-induced loops were studied by dislocation dynamics. • Dislocation dynamics results are directly compared to molecular dynamics results. • The complex elementary reactions are successfully reproduced. • The critical shear stress to overcome individual loops if reproduced quantitatively. - Abstract: Interstitial dislocation loops with Burgers vector of 〈1 0 0〉 type are formed in α-iron under neutron or heavy ion irradiation. As the density and size of these loops increase with radiation dose and temperature, these defects are thought to play a key role in hardening and subsequent embrittlement of iron-based steels. The aim of the present work is to study the pinning strength of the loops on mobile dislocations. Prior to run massive Dislocation Dynamics (DD) simulations involving experimentally representative array of radiation defects and dislocations, the DD code and its parameterization are validated by comparing the individual loop–dislocation reactions with those obtained from direct atomistic Molecular Dynamics (MD) simulations. Several loop–dislocation reaction mechanisms are successfully reproduced as well as the values of the unpinning stress to detach mobile dislocations from the defects.

  10. The dislocation of medical dominance: making space for interprofessional care.

    Science.gov (United States)

    Bleakley, Alan

    2013-09-01

    The historical transition of modern medicine from an autonomous profession to a team-based interprofessional practice can be described in terms of space rather than time, with "place" as the unit of analysis. Imagining modern medicine spatially was instigated by Foucault, who described medical dominance as a territorializing of both individual body spaces and public spaces--the former through the diagnostic medical gaze, the latter in a gaze of health surveillance. However, much has happened since Foucault's (1963) analysis. The diagnostic gaze has been dispersed to develop a collaborative gaze including patients and healthcare professionals; political interests have appropriated the public health gaze; and the medical profession is subject to democratic processes of accountability. Medicine has lost its territorial imperative as new "liquid" and "nomadic" work practices emerge, making space for interprofessional care. Such dislocation of medical dominance and its multiple relocations are poorly theorised. Deleuze and Guattari distinguish between "striated" and "smooth" spaces. Striated space is associated with hierarchies and boundaries, where smooth space includes boundary crossing and democratic collaboration. Smooth or liminal spaces in hospitals, such as corridors, can paradoxically act as catalysts for collaboration or assembly democracy, affording opportunities for improvised interprofessional encounters. Such encounters can act as an antidote to planned protocols or imperatives for interprofessional collaboration.

  11. Subacute dislocation of the elbow following Galeazzi fracture-dislocation of the radius: A case report.

    Science.gov (United States)

    Rajeev, Aysha; Senevirathna, Shanaka; Harrison, John

    2011-12-20

    The Galeazzi fracture-dislocation was originally described by Sir Astley Cooper in 1822 but was named after Italian surgeon Ricardo Galeazzi in 1934. It is an injury classified as a radial shaft fracture with associated dislocation of the distal radioulnar joint and disruption of the forearm axis joint. The associated distal radioulnar joint injury may be purely ligamentous in nature, tearing the triangular fibrocartilaginous complex, or involve bony tissue (that is, ulnar styloid avulsions) or both. We report this case because of the rare association of posterior dislocation of the elbow along with Galeazzi fracture-dislocation. To the best of our knowledge, this has not been previously reported in the English literature. A 26-year-old Caucasian man presented to our department after a fall from a motorbike. He sustained a closed, isolated Galeazzi fracture-dislocation of the right forearm and no associated elbow injuries, and this necessitated open reduction and internal fixation of the radius. Post-operative radiographs films were satisfactory. However, clinical and radiological evidence of ipsilateral elbow dislocation was noted at a five-week follow-up, subsequently requiring open reduction of the joint and collateral ligament repair. Our patient was noted to have full elbow and forearm function at three months. Although the Galeazzi fracture-dislocation has been classically described as involving only the distal radioulnar joint, traumatic forces can be transmitted to the elbow via the interosseous membrane of the forearm. This can lead to instability of the elbow joint. Therefore, we recommend that, in every case of forearm fracture, both elbow and wrist joints be assessed clinically as well as radiologically for subluxation or dislocation.

  12. Hydrogen accumulation around dislocation loops and edge dislocations: from atomistic to mesoscopic scales in BCC tungsten

    Science.gov (United States)

    De Backer, A.; Mason, D. R.; Domain, C.; Nguyen-Manh, D.; Marinica, M.-C.; Ventelon, L.; Becquart, C. S.; Dudarev, S. L.

    2017-12-01

    In a fusion tokamak, the plasma interacts with the metallic wall and the divertor. Hydrogen isotopes penetrate and diffuse into the material and interact with defects where they are trapped. Neutrons produced by the fusion reactions in the plasma are stopped in the material, creating defects, including vacancy and interstitial clusters, and dislocation loops. The trapping of hydrogen in vacancies has been extensively investigated. In our recent paper (De Backer et al 2017 Nucl. Fusion), we proposed a multi-scale model for H trapping and accumulation around interstitial defects, dislocation loops and dislocation lines. These defects create a long-range elastic field that attracts and may retain H atoms. A two-shell model with a short-range core region and a long-range elastic shell has been parameterized using a database of density functional theory (DFT) calculations. This model gives the number of H atoms forming the Cottrell atmosphere of a defect at finite temperature. In this paper, we present new DFT calculations of large dislocation loops decorated with up to 80 H, and explore our two-shell model in fusion relevant conditions. We conclude that large dislocation loops and edge dislocations can trap a significant number of hydrogen atoms in the core at temperatures up to 800 K, and also in the elastic field if the background hydrogen concentration is high.

  13. Boundary Spanning

    DEFF Research Database (Denmark)

    Zølner, Mette

    The paper explores how locals span boundaries between corporate and local levels. The aim is to better comprehend potentialities and challenges when MNCs draws on locals’ culture specific knowledge. The study is based on an in-depth, interpretive case study of boundary spanning by local actors in...... approach with pattern matching is a way to shed light on the tacit local knowledge that organizational actors cannot articulate and that an exclusively inductive research is not likely to unveil....

  14. Detection of grain-boundary resistance to slip transfer using nanoindentation

    NARCIS (Netherlands)

    Soer, WA; De Hosson, JTM

    2005-01-01

    Nanoindentation measurements near a high-angle grain boundary in a Fe-14%Si bicrystal showed dislocation pile-up and transmission across the boundary. The latter is observed as a characteristic displacement jump, from which the Hall-Petch slope can be calculated as a measure for the slip

  15. Work softening in nanocrystalline materials induced by dislocation annihilation

    DEFF Research Database (Denmark)

    Ungar, Tamas; Li, Li; Tichy, Geza

    2011-01-01

    Cold rolling reduces the quantity of dislocation densities in Ni–18% Fe alloys prepared by electrochemical deposition. The dislocation density evolution proposed earlier for the linearly decreasing work-hardening rate during stage III is revisited. The solution of the differential equation predicts...... that when the initial dislocation density is smaller or larger than the saturation value, then the dislocation density will increase or decrease during further plastic deformation. The predictions are verified by experimental values of dislocation densities determined by X-ray line-profile analysis....

  16. Grain-size dependent accommodation due to intragranular distributions of dislocation loops

    International Nuclear Information System (INIS)

    Richeton, T.; Berbenni, S.; Berveiller, M.

    2009-01-01

    A grain-size dependent accommodation law for polycrystals is deduced from an inclusion/matrix problem (i.e., each grain is seen as embedded in a homogeneous equivalent medium) where plastic strain inside the inclusion is given as a discrete distribution of circular coaxial glide dislocation loops. The loops are assumed constrained at spherical grain boundaries. From thermodynamic considerations specific to a process of identical plastification in all the loops (considered as 'super-dislocations'), an average back-stress over the grain is derived. In order to compute the very early stages of plastic deformation in a face-centred cubic polycrystal, this back-stress is incorporated into a diluted model in terms of concentration of plastic grains. Contrary to conventional mean-field approaches, a grain-size effect is obtained for the initial overall strain-hardening behaviour. This size effect results from an intrinsic contribution of intragranular slip heterogeneities on the kinematical hardening

  17. The glide of screw dislocations in bcc Fe: Atomistic static and dynamic simulations

    International Nuclear Information System (INIS)

    Chaussidon, Julien; Fivel, Marc; Rodney, David

    2006-01-01

    We present atomic-scale simulations of screw dislocation glide in bcc iron. Using two interatomic potentials that, respectively, predict degenerate and non-degenerate core structures, we compute the static 0 K dependence of the screw dislocation Peierls stress on crystal orientation and show strong boundary condition effects related to the generation of non-glide stress components. At finite temperatures we show that, with a non-degenerate core, glide by nucleation/propagation of kink-pairs in a {1 1 0} glide plane is obtained at low temperatures. A transition in the twinning region, towards an average {1 1 2} glide plane, with the formation of debris loops is observed at higher temperatures

  18. Fostering incidental experiences of nature through green infrastructure planning

    DEFF Research Database (Denmark)

    Beery, Thomas H; Raymond, Christopher M; Kyttä, Marketta

    2017-01-01

    Concern for a diminished human experience of nature and subsequent decreased human well-being is addressed via a consideration of green infrastructure's potential to facilitate unplanned or incidental nature experience. Incidental nature experience is conceptualized and illustrated in order...... to consider this seldom addressed aspect of human interaction with nature in green infrastructure planning. Special attention has been paid to the ability of incidental nature experience to redirect attention from a primary activity toward an unplanned focus (in this case, nature phenomena). The value...... of such experience for human well-being is considered. The role of green infrastructure to provide the opportunity for incidental nature experience may serve as a nudge or guide toward meaningful interaction. These ideas are explored using examples of green infrastructure design in two Nordic municipalities...

  19. The Radiological Prevalence of Incidental Kienböck Disease

    Directory of Open Access Journals (Sweden)

    Saroj K. Golay

    2016-07-01

    Full Text Available Background:To determine the prevalence of incidental Kienböck disease.   Methods: A retrospective analysis of 150,912 radiological reports or images obtained over a five year period was performed of 76,174 patients who underwent a radiograph or computed tomography scan which included the wrist, in Edinburgh and Lothian, UK. Results: There were 5 cases of incidental Kienböck disease and 13 cases of symptomatic Kienböck disease. There were no significant differences in age, sex, ethnicity, comorbidities, smoking status, excess alcohol use or Lichtman stage between the incidental and symptomatic Kienböck groups. Conclusion: The radiological prevalence of incidental Kienböck disease was 0.0066% or 7 in 100,000 patients.

  20. Recombination properties of dislocations in GaN

    Science.gov (United States)

    Yakimov, Eugene B.; Polyakov, Alexander Y.; Lee, In-Hwan; Pearton, Stephen J.

    2018-04-01

    The recombination activity of threading dislocations in n-GaN with different dislocation densities and different doping levels was studied using electron beam induced current (EBIC). The recombination velocity on a dislocation, also known as the dislocation recombination strength, was calculated. The results suggest that dislocations in n-GaN giving contrast in EBIC are charged and surrounded by a space charge region, as evidenced by the observed dependence of dislocation recombination strength on dopant concentration. For moderate (below ˜108 cm-2) dislocation densities, these defects do not primarily determine the average diffusion length of nonequilibrium charge carriers, although locally, dislocations are efficient recombination sites. In general, it is observed that the effect of the growth method [standard metalorganic chemical vapor deposition (MOCVD), epitaxial lateral overgrowth versions of MOCVD, and hydride vapor phase epitaxy] on the recombination activity of dislocations is not very pronounced, although the average diffusion lengths can widely differ for various samples. The glide of basal plane dislocations at room temperature promoted by low energy electron irradiation does not significantly change the recombination properties of dislocations.

  1. Cooperative Research to Evaluate an Incidental Catch Distribution Forecast

    Directory of Open Access Journals (Sweden)

    Sara M. Turner

    2017-05-01

    Full Text Available Concern over incidental catches in commercial fisheries has been increasing, and while simple mitigation strategies have been effective, few effective mitigation strategies have been established for more complex species interactions. Incidental catches of alewife (Alosa pseudoharengus and blueback herring (A. aestivalis in the commercial Atlantic herring (Clupea harengus fishery have received substantial attention on the Northeast U.S. continental shelf, despite an existing bycatch avoidance program. This study evaluates the utility of existing species distribution forecasts to predict river herring catches in the southern New England small mesh bottom trawl Atlantic herring fishery, with the ultimate goal of incorporating incidental catch forecasts into the bycatch avoidance program. Commercial Atlantic herring bottom trawl vessels assisted with field-based evaluation of alewife, blueback herring, and Atlantic herring species distribution forecast models. Vessels were equipped with conductivity, temperature, and depth probes, and sampling occurred throughout the fishery season (January–March. Locations of expected low and high forecasted incidental catches were sampled, as well as locations the captain expected to find low and high incidental catches. This allowed us to sample within the spatial area the fishery occurs, and to evaluate the forecasted conditions, and predictions, at the spatial scale of the fishery. Catch differences between high and low probability stations were small and variable, as were differences in modeled probability of species presence. No differences were observed between observations at model-predicted stations and captain-selected stations. The sampling provided a better understanding of the potential effectiveness of distribution forecasts for further reducing incidental catches. Existing models have limited use at the spatial scale of this fishery, but could be improved by developing models with fishery

  2. Esplenectomía incidental: ¿Está justificada?

    Directory of Open Access Journals (Sweden)

    Eddy Sierra Enrique

    1997-12-01

    Full Text Available Se revisaron 77 historias clínicas de pacientes que presentaban lesiones incidentales del bazo ocurridas entre 1985 y 1994, durante operaciones intraabdominales y por examen laparoscópico. Las funciones inmunológicas del bazo y su papel contra las infecciones están bien definidas, por lo cual al ser suprimido este órgano a consecuencia de lesiones incidentales, favorecen las infecciones en dichos pacientes de por vida. De las 77 lesiones incidentales se realizaron 47(61 % esplenectomías incidentales y 30(39 % cirugías conservadoras. La úlcera duodenal y la hernia hiatal son las causas principales de esplenectomía incidental. Se presentaron 11 infecciones (23,4 % y 1 fallecido (2,1 % en la esplenectomía incidental contra 1 infección (3,3 % y ningún fallecido en la cirugía conservadora. Se llega a la conclusión de que la esplenectomía no está justificada dadas las desventajas que presenta77 medical histories of patients who presented incidental injuries of the spleen occurred between 1985 and 1994, during intraabdominal operations and by laparoscopic examination, were reviewed. The immunological functions of the spleen and its role against infections are well defined, so the removal of this organ due to incidental injuries favors the appearance of infections in these patients for the rest of their lives. Of the 77 incidental injuries 47 (61 % incidental splenectomies and 30 (39 % conservative surgeries were performed. Duodenal ulcer and hiatal hernia proved to be the main causes of incidental splenectomy. There were 11 infections (23.4 % and 1 death (2.1 % in the incidental splenectomy compared with 1 infection (3.3 % and no death in the conservative surgery. It is concluded that splenectomy is not justified because of its disadvantages

  3. Ultrasound as a probe of dislocation density in aluminum

    International Nuclear Information System (INIS)

    Mujica, Nicolás; Cerda, Maria Teresa; Espinoza, Rodrigo; Lisoni, Judit; Lund, Fernando

    2012-01-01

    Graphical abstract: Display Omitted - Abstract: Dislocations are at the heart of the plastic behavior of crystalline materials yet it is notoriously difficult to perform quantitative, non-intrusive measurements of their single or collective properties. Dislocation density is a critical variable that determines dislocation mobility, strength and ductility. On the one hand, individual dislocations can be probed in detail with transmission electron microscopy. On the other hand, their collective properties must be simulated numerically. Here we show that ultrasound technology can be used to measure dislocation density. This development rests on theory—a generalization of the Granato–Lücke theory for the interaction of elastic waves with dislocations—and resonant ultrasound spectroscopy (RUS) measurements. The chosen material is aluminum, to which different dislocation contents were induced through annealing and cold-rolling processes. The dislocation densities obtained with RUS compare favorably with those inferred from X-ray diffraction, using the modified Williamson–Hall method.

  4. Atomic-scale structure relaxation, chemistry and charge distribution of dislocation cores in SrTiO3.

    Science.gov (United States)

    Gao, Peng; Ishikawa, Ryo; Feng, Bin; Kumamoto, Akihito; Shibata, Naoya; Ikuhara, Yuichi

    2018-01-01

    By using the state-of-the-art microscopy and spectroscopy in aberration-corrected scanning transmission electron microscopes, we determine the atomic arrangements, occupancy, elemental distribution, and the electronic structures of dislocation cores in the 10° tilted SrTiO 3 bicrystal. We identify that there are two different types of oxygen deficient dislocation cores, i.e., the SrO plane terminated Sr 0.82 Ti 0.85 O 3-x (Ti 3.67+ , 0.48 ≤ x ≤ 0.91) and TiO 2 plane terminated Sr 0.63 Ti 0.90 O 3-y (Ti 3.60+ , 0.57 ≤ y ≤ 1). They have the same Burgers vector of a[100] but different atomic arrangements and chemical properties. Besides the oxygen vacancies, Sr vacancies and rocksalt-like titanium oxide reconstruction are also identified in the dislocation core with TiO 2 plane termination. Our atomic-scale study reveals the true atomic structures and chemistry of individual dislocation cores, providing useful insights into understanding the properties of dislocations and grain boundaries. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. BILATERAL PATHOLOGICAL HIP DISLOCATION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Yuriy E. Garkavenko

    2017-03-01

    Full Text Available Introduction. Pathological dislocation of the hip is one of the most severe complications of acute hematogenous osteomyelitis. The program of treatment for children with pathological hip dislocation is complex, but it has been sufficiently developed and implemented very successfully. At the same time, the available literature provides no cases of treating children with bilateral pathological hip dislocations after hematogenous osteomyelitis. There is no information on the incidence of such cases or in regards to remote functional results. Materials and methods. The results of the treatment of 18 children with bilateral pathological dislocation of the hip after hematogenous osteomyelitis are presented, which constituted 23.1% of the total number of patients (78 who underwent surgery in 2000–2016 for the diagnosis of pathological hip dislocation. Both hip joints were surgically operated on in 12 patients, while one hip joint was operated on in 6 patients. To assess the anatomical and functional state of hip joints, the clinical and roentgenological diagnostic techniques were used. Results and discussion. To stabilize and restore the function of the hip joints, 18 children underwent 30 surgical interventions: simple open hip reduction (19 and open hip reduction with hip arthroplasty with one (6 or two (5 demineralized osteochondral allogeneic grafts. The decision regarding the possibility of performing surgical intervention on the second hip joint was made only after a child's check-up examination was complete and after positive information about the anatomical and functional state of the operated hip joint was obtained. According to these criteria, 14 (77.8% children underwent surgical treatment of the second hip joint 1–1.5 years after the course of conservative measures to restore the range of motion in the previously operated hip joint. Over a period of 1–12 years, 17 patients were examined, 10 of which underwent an operation on both

  6. Incidental mood state before dissonance induction affects attitude change.

    Directory of Open Access Journals (Sweden)

    Marie-Amélie Martinie

    Full Text Available The way that incidental affect impacts attitude change brought about by controlled processes has so far been examined when the incidental affective state is generated after dissonance state induction. We therefore investigated attitude change when the incidental mood occurs prior to dissonance state induction. We expected a negative mood to induce systematic processing, and a positive mood to induce heuristic processing. Given that both systematic processing and attitude change are cognitively costly, we expected participants who experienced the dissonance state in a negative mood to have insufficient resources to allocate to attitude change. In our experiment, after mood induction (negative, neutral or positive, participants were divided into low-dissonance and high-dissonance groups. They then wrote a counterattitudinal essay. Analysis of their attitudes towards the essay topic indicated that attitude change did not occur in the negative incidental mood condition. Moreover, written productivity-one indicator of cognitive resource allocation-varied according to the type of incidental mood, and only predicted attitude change in the high-dissonance group. Our results suggest that incidental mood before dissonance induction influences the style of information processing and, by so doing, affects the extent of attitude change.

  7. Incidental mood state before dissonance induction affects attitude change.

    Science.gov (United States)

    Martinie, Marie-Amélie; Almecija, Yves; Ros, Christine; Gil, Sandrine

    2017-01-01

    The way that incidental affect impacts attitude change brought about by controlled processes has so far been examined when the incidental affective state is generated after dissonance state induction. We therefore investigated attitude change when the incidental mood occurs prior to dissonance state induction. We expected a negative mood to induce systematic processing, and a positive mood to induce heuristic processing. Given that both systematic processing and attitude change are cognitively costly, we expected participants who experienced the dissonance state in a negative mood to have insufficient resources to allocate to attitude change. In our experiment, after mood induction (negative, neutral or positive), participants were divided into low-dissonance and high-dissonance groups. They then wrote a counterattitudinal essay. Analysis of their attitudes towards the essay topic indicated that attitude change did not occur in the negative incidental mood condition. Moreover, written productivity-one indicator of cognitive resource allocation-varied according to the type of incidental mood, and only predicted attitude change in the high-dissonance group. Our results suggest that incidental mood before dissonance induction influences the style of information processing and, by so doing, affects the extent of attitude change.

  8. Transtriquetral perihamate fracture-dislocation: case report

    Directory of Open Access Journals (Sweden)

    Frederico Barra de Moraes

    2016-08-01

    Full Text Available ABSTRACT The wrist is a region that is very vulnerable to injuries of the extremities. Among these injuries, fractures of the pyramidal bone (or triquetrum in association with dislocation of the hamate and carpal instability are uncommon. They are generally correlated with high-energy trauma and may be associated with neurovascular deficits, muscle-tendon disorders, skin lesions or injuries to other carpal bones. Thus, in this report, one of these rare cases of transtriquetral perihamate fracture-dislocation with carpal instability is presented, diagnosed by means of radiography on the right wrist of the patient who presented pain, edema and limitation of flexion-extension of the carpus after trauma to the region. The stages of attending to the case are described, from the initial consultation to the surgical treatment and physiotherapy, which culminated in restoration of the strength and range of motion of the wrist.

  9. Blurring Boundaries

    DEFF Research Database (Denmark)

    Neergaard, Ulla; Nielsen, Ruth

    2010-01-01

    of welfare functions into EU law both from an internal market law and a constitutional law perspective. The main problem areas covered by the Blurring Boundaries project were studied in sub-projects on: 1) Internal market law and welfare services; 2) Fundamental rights and non-discrimination law aspects......; and 3) Services of general interest. In the Blurring Boundaries project, three aspects of the European Social Model have been particularly highlighted: the constitutionalisation of the European Social Model, its multi-level legal character, and the clash between market access justice at EU level...... and distributive justice at national level....

  10. DISLOCATIONS MOBILITY UNDER THE IMAGE FORCE EFFECT IN BICRYSTALS OF CFC MATERIALS: CU-X, X = PB, AL, AU, AG AND NI

    Directory of Open Access Journals (Sweden)

    A OUCHTATI

    2015-06-01

    Full Text Available The image force undergone by a matrix dislocations close and parallel to an interphase boundary is studied in Cu-X bicrystals (with X = Pb, Al, Au, Ag, Ni for disorientations ranging between 0° and 90°.  Dislocations have a Burgers vector  = a/2 [110]. The elastic energy of dislocation-boundary interaction is calculated within the framework of anisotropic linear elasticity. The elastic energy is related to the difference of the two metals shear moduli. It is about a few hundred pico Joule per meter. The image force can be repulsive or attractive according to the sign and the intensity of shear moduli difference. The isoenergy maps have various symmetries according to the disorientation.

  11. Incidental Vocabulary Learning: A Semantic Field Approach

    Directory of Open Access Journals (Sweden)

    Parvaneh Khosravizadeh

    2011-10-01

    Full Text Available

    This study is an attempt to explore the difference between acquiring new words with different semantic fields to which they belong. In other words, the purpose of this study is to scrutinize the contribution of semantic field theory in learning new vocabulary items in an EFL setting. Thirty-eight students of three different levels of education took part in this research. They were exposed to some new words from four different semantic fields, and then they were tested on their acquisition of the words meaning. This exposure was through reading texts and the aim of reading was just comprehension, therefore the words were acquired incidentally. The outcome showed significant differences between groups with different levels of education regarding retention of words from different semantic fields.

  12. Color vision and fatigue: an incidental finding.

    Science.gov (United States)

    Hovis, Jeffery K; Ramaswamy, Shankaran

    2007-11-01

    Because there is little information available as to how fatigue and color vision interact, we present some incidental findings on how a protanope and a color-normal perform on several color vision tests after 1 night of sleep deprivation. A series of clinically and occupationally based color vision tests were administered to a protanope and a color-normal subject after they had stayed awake all night and after a regular night's sleep. There was essentially no change in their performance on the clinical color vision tests; however, both did worse on the occupationally based color vision tests after 1 night of sleep deprivation. The color-normal made numerous errors in identifying colors displayed on a video display terminal, whereas the protanope had a large increase in errors on the CN Lantern Test. Both subjects passed these respective tests after a regular night's sleep. The primary reason for color-normal's poor performance on the video display terminal test was probably due to a decrement in his visuo-motor control rather than a loss in color discrimination. In contrast, the protanope's poor performance on the lantern test was probably due to the additive effects of the inherent limitations of his visual system and fatigue.

  13. Incidental breast carcinoma in reduction mammoplasty.

    Science.gov (United States)

    Huysmans, Michaël; Bronckaers, Marc; Schillebeeckx, Charlotte; Servaes, Dirk

    2017-10-01

    The objective of this study was to analyze the incidence and treatment options of occult cancer or atypical lesions found in the histopathological examination of reduction mammoplasty (RM) specimens. The role of preoperative mammography and systematic histopathological examination are discussed. We performed a retrospective single-center database review of all patients who underwent a RM between January 2005 and December 2014. Preoperative examination, histopathological findings and follow-up were documented. A total of 1045 patients underwent RM, of which 97% were bilateral (1021). All patients received a mammography and routine clinical examination to exclude cancer preoperatively. The overall mean patient age was 40.2 years (14.2-73.4). A total of 19 patients (1.18%) had significant histopathological findings, all of whom were over 40 years of age. There were 4 incidental carcinomas (0.38%), of which 2 were DCIS (0.19%) and 2 invasive ductal carcinomas (0.19%). Incidence of postoperative diagnosis of occult breast cancer in RM specimens remains low, but poses significant therapeutic challenges. While emphasis should lay on preoperative diagnostics, routine histological analysis of RM specimens is recommended.

  14. Incidental mastoid opacification in children on MRI

    International Nuclear Information System (INIS)

    Singh, Sumit; Kuruva, Manohar; Rettiganti, Mallikarjuna Rao; Qin, Curtis; Hegde, Shilpa V.

    2016-01-01

    The opacification the mastoid cavity is frequently reported by radiologists on cross-sectional imaging done for non-otological indications. It is well known that presence of fluid the mastoid does not amount to mastoiditis. This study seeks to provide an evidence-based confirmation of this known finding. The purpose of our study was to determine the prevalence of mastoid opacification in children undergoing outpatient brain MRI examination. Our study included 515 outpatient children who had brain MRI for indications other than mastoiditis or otitis media from January 2014 to March 2014. Children with history of skull base trauma or radiation were excluded. The age range was 15 days to 18 years. The overall prevalence of mastoid opacification was determined using one sample proportion and exact 95% Clopper-Pearson confidence intervals. The prevalence of mastoid opacification was analyzed based on gender, age and presenting symptoms using chi-square test of association. One hundred ten children (21.4%) had mastoid opacification. Younger patients tended to have higher opacification rates with the prevalence in children younger than 1 year of age and between 1 and 2 years of age as high as 41.7% (20/48) and 47.5% (38/80), respectively. The diagnosis of mastoiditis in children should not be based upon a radiologist's report of finding fluid or mucosal thickening in the mastoid air cells as incidental opacification the mastoid is seen frequently. (orig.)

  15. Incidental mastoid opacification in children on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sumit; Kuruva, Manohar [University of Arkansas for Medical Sciences, Pediatric Radiology, Little Rock, AR (United States); Rettiganti, Mallikarjuna Rao [University of Arkansas for Medical Sciences and Arkansas Children' s Hospital Research Institute, Biostatistics Program, Department of Pediatrics, Little Rock, AR (United States); Qin, Curtis [Georgetown University Hospital, Radiology, Washington, DC (United States); Hegde, Shilpa V. [University of Pittsburgh Medical Centre, Section of Neuroradiology, Pittsburgh, PA (United States)

    2016-05-15

    The opacification the mastoid cavity is frequently reported by radiologists on cross-sectional imaging done for non-otological indications. It is well known that presence of fluid the mastoid does not amount to mastoiditis. This study seeks to provide an evidence-based confirmation of this known finding. The purpose of our study was to determine the prevalence of mastoid opacification in children undergoing outpatient brain MRI examination. Our study included 515 outpatient children who had brain MRI for indications other than mastoiditis or otitis media from January 2014 to March 2014. Children with history of skull base trauma or radiation were excluded. The age range was 15 days to 18 years. The overall prevalence of mastoid opacification was determined using one sample proportion and exact 95% Clopper-Pearson confidence intervals. The prevalence of mastoid opacification was analyzed based on gender, age and presenting symptoms using chi-square test of association. One hundred ten children (21.4%) had mastoid opacification. Younger patients tended to have higher opacification rates with the prevalence in children younger than 1 year of age and between 1 and 2 years of age as high as 41.7% (20/48) and 47.5% (38/80), respectively. The diagnosis of mastoiditis in children should not be based upon a radiologist's report of finding fluid or mucosal thickening in the mastoid air cells as incidental opacification the mastoid is seen frequently. (orig.)

  16. Traumatic atlantooccipital dislocation injury in children.

    Science.gov (United States)

    Nichols, J; West, J S

    1994-10-01

    The tragedy of trauma turns into triumph when the surgery team members' efforts result in victory for the patient. Nowhere is this more true than in successful pediatric trauma care. Giving a child a second chance at life and the family an opportunity for a new beginning is the highest reward for the trauma team's years of professional training and practice. Traumatic atlantoocipital dislocation injury usually results in death, but recent neurosurgery trauma advances are increasing pediatric survival rates.

  17. Congenital hip dislocation: Radiological screening or diagnosis?

    International Nuclear Information System (INIS)

    Kalifa, G.; Faure, C.

    1987-01-01

    Congenital hip dislocation is a perfect example of public health problems: its incidence is high 0.6, to 2% of newborns in France and an early detection allows an easy and successful treatment. The current situation in our country is not satisfactory for several reasons: - Too many children are treated without reasons because of misleading radiological pictures; - Conversely, some dislocations are discovered only at the walking age, the treatment becoming then more difficult and less effective; - Almost 300,000 radiological examinations of the hip for screening are performed each year and among them 100,000 in newborns. This is not satisfactory as it is commonly admitted now that radiological examination at birth is unreliable and frequently misleading. For all these reasons a special working group has been settled up by the General Direction of Health, including physicians of different practices, from different specialities. The conclusion of this group will be published in a special booklet and can be summarized as follows: The group recommends to perform detection of congenital hip dislocation mainly by the clinical examination. This examination may be difficult but it must be performed very early, the first day of life, repeated several times, at the end of the first week and during the first, second, and third month. Every baby in this country must undergo several clinical examinations up to one year of age

  18. Open Galeazzi fracture with ipsilateral elbow dislocation.

    Science.gov (United States)

    Adanır, Oktay; Yüksel, Serdar; Beytemur, Ozan; Güleç, M Akif

    2016-08-01

    Combination of the Galeazzi fracture and dislocation of the elbow joint in same extremity is very rare. In this article, we report a 26-year-old male patient with a posterolateral dislocation of the elbow and ipsilateral volar type Galeazzi fracture. We performed closed reduction for the elbow dislocation during admission to the emergency department. Patient was taken to the operating room in the sixth hour of his application to emergency department and open wound on the ulnovolar region of the wrist was closed primarily after irrigation and debridement. We performed open reduction and internal fixation of the radial fracture with a dynamic compression plate. After fixation, we evaluated the stability of the elbow joint and distal radioulnar joint. Distal radioulnar joint was unstable under fluoroscopic examination and fixed with one 1.8 mm Kirschner wire in a pronated position. Then, elbow joint was stable. One year after surgery, patient had no pain or sings of instability. At the last follow-up, range of motion of the elbow was 10°-135° and forearm pronation and supination were 70°.

  19. Dislocation movement and hysteresis in Maraging blades

    Energy Technology Data Exchange (ETDEWEB)

    Di Cintio, Arianna; Ascione, Maria; De Salvo, Riccardo [LIGO Laboratory, California Institute of Technology, MS 18-34, 1200 E.California Blvd., Pasadena, CA, 91125 (United States); Marchesoni, Fabio [INFN-VIRGO Project Dipartimento di Fisica, Universita' di Camerino, I-62032 Camerino (Italy); Bhawal, Abhik, E-mail: desalvo@ligo.caltech.ed [Arcadia High School, Arcadia, CA (United States)

    2009-10-21

    All seismic isolation systems developed for gravitational-wave interferometric detectors, such as LIGO, Virgo and TAMA, make use of Maraging steel blades. The dissipation properties of these blades have been studied at low frequencies, by using a geometric anti-spring (GAS) filter, which allowed the exploration of resonant frequencies below 100 mHz. At this frequency an anomalous transfer function was observed in the GAS filter: this is one of several motivations for this work. The many unexpected effects observed and measured are explainable by the collective movement of dislocations inside the material described with the statistic of self-organised criticality. At low frequencies, below 200 mHz, the dissipation mechanism can subtract elasticity from the system even leading to sudden collapse. While Young's modulus is weaker, excess dissipation is observed. At higher frequencies the applied stress is probably too fast to allow the full growth of dislocation avalanches, and less losses are observed, thus explaining the higher Q-factor in this frequency range. The domino effect that leads to the release of entangled dislocations allows the understanding of the random walk of the Virgo and TAMA inverted pendula, the anomalous GAS filter transfer function as well as the loss of predictability of the ring-down decay in the LIGO seismic attenuation system inverted pendula.

  20. Thoracic fractures and dislocations in motorcyclists

    International Nuclear Information System (INIS)

    Daffner, R.H.; Deeb, Z.L.; Rothfus, W.E.

    1987-01-01

    Motorcyclists who are involved in accidents generally suffer severe multiple injuries, some of which are not readily apparent on initial examination. One such subtle injury is fracture, with or without dislocation, in the upper thoracic spine. The severe spinal cord damage produced by the injury is often overshadowed by cerebral or cervical injury. Proper diagnosis is further hampered by the fact that the upper thoracic region is difficult to examine radiographically on plain films, particularly when using portable equipment. Of a group of 14 motorcyclists having 26 fractures and/or dislocations in the thoracic region, 12 had 24 injuries between T3 and T8. These 24 injuries represented 56% of the fractures and/or dislocations encountered in a larger study of trauma to the thoracic vertebral column. All of these were flexion injuries, suffered when the individual was thrown from the motorcycle and struck a large, solid object. In three cases, the diagnosis was delayed as much as 48 h because proper films were not obtained initially. Because of the serious consequences of delayed treatment, we recommended that all motorcyclists who have sustained severe trauma be examined by overpenetrated film of the upper thoracic region. (orig.)

  1. Competing Grain Boundary and Interior Deformation Mechanisms with Varying Sizes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei [University of Tennessee (UT); Gao, Yanfei [ORNL; Nieh, T. G. [University of Tennessee, Knoxville (UTK)

    2018-01-01

    In typical coarse-grained alloys, the dominant plastic deformations are dislocation gliding or climbing, and material strengths can be tuned by dislocation interactions with grain boundaries, precipitates, solid solutions, and other defects. With the reduction of grain size, the increase of material strengths follows the classic Hall-Petch relationship up to nano-grained materials. Even at room temperatures, nano-grained materials exhibit strength softening, or called the inverse Hall-Petch effect, as grain boundary processes take over as the dominant deformation mechanisms. On the other hand, at elevated temperatures, grain boundary processes compete with grain interior deformation mechanisms over a wide range of the applied stress and grain sizes. This book chapter reviews and compares the rate equation model and the microstructure-based finite element simulations. The latter explicitly accounts for the grain boundary sliding, grain boundary diffusion and migration, as well as the grain interior dislocation creep. Therefore the explicit finite element method has clear advantages in problems where microstructural heterogeneities play a critical role, such as in the gradient microstructure in shot peening or weldment. Furthermore, combined with the Hall-Petch effect and its breakdown, the above competing processes help construct deformation mechanism maps by extending from the classic Frost-Ashby type to the ones with the dependence of grain size.

  2. Kinetic origin of grain boundary migration, grain coalescence, and defect reduction in the crystallization of quenched two-dimensional Yukawa liquids

    Science.gov (United States)

    Chen, Meng-Chun; Yang, Chi; I, Lin

    2014-11-01

    The kinetic origin of grain boundary migration, grain coalescence, and defect reduction in the crystallization of quenched two-dimensional Yukawa liquids are numerically investigated. It is found that, in grain coalescence, stick-slip cracking the region in front of the grain boundary into smaller subgrains corotating with small angle, followed by healing, is the key for aligning lattice misorientation and inducing grain boundary stick-slip advance. Cracking is initiated from the weakly interlocked dislocation along its Burgers vector, which in turn causes dislocation motion along the crack. The cascaded scattering and recombination of two dislocations with 60∘ and 120∘ Burgers vector angle difference into two and one dislocations are the major processes for dislocation motion and reduction, respectively, in grain boundary migration. A rough grain boundary with large curvature easily supports the above process and induces high grain boundary mobility. Along a straight smooth grain boundary, the parallel Burgers vectors of the string of dislocations hinder defect reduction and induce coalescence stagnation.

  3. Crystallographic fatigue crack growth in a polycrystal: simulations based on FEM and discrete dislocation dynamics

    International Nuclear Information System (INIS)

    Bertolino, G.; Sauzay, M.; Bertolino, G.; Doquet, V.

    2003-01-01

    An attempt to model the variability of short cracks development in high-cycle fatigue is made by coupling finite element calculations of the stresses ahead of a microcrack in a polycrystal with simulations of crack growth along slip planes based on discrete dislocations dynamics. The model predicts a large scatter in growth rates related to the roughness of the crack path. It also describes the influence of the mean grain size and the fact that overloads may suppress the endurance limit by allowing arrested cracks to cross the grain boundaries. (authors)

  4. Polymorphism of dislocation core structures at the atomic scale.

    Science.gov (United States)

    Wang, Zhongchang; Saito, Mitsuhiro; McKenna, Keith P; Ikuhara, Yuichi

    2014-01-01

    Dislocation defects together with their associated strain fields and segregated impurities are of considerable significance in many areas of materials science. However, their atomic-scale structures have remained extremely challenging to resolve, limiting our understanding of these ubiquitous defects. Here, by developing a complex modelling approach in combination with bicrystal experiments and systematic atomic-resolution imaging, we are now able to pinpoint individual dislocation cores at the atomic scale, leading to the discovery that even simple magnesium oxide can exhibit polymorphism of core structures for a given dislocation species. These polymorphic cores are associated with local variations in strain fields, segregation of defects, and electronic states, adding a new dimension to understanding the properties of dislocations in real materials. The findings advance our fundamental understanding of basic behaviours of dislocations and demonstrate that quantitative prediction and characterization of dislocations in real materials is possible.

  5. Riemann–Cartan Geometry of Nonlinear Dislocation Mechanics

    KAUST Repository

    Yavari, Arash

    2012-03-09

    We present a geometric theory of nonlinear solids with distributed dislocations. In this theory the material manifold-where the body is stress free-is a Weitzenböck manifold, that is, a manifold with a flat affine connection with torsion but vanishing non-metricity. Torsion of the material manifold is identified with the dislocation density tensor of nonlinear dislocation mechanics. Using Cartan\\'s moving frames we construct the material manifold for several examples of bodies with distributed dislocations. We also present non-trivial examples of zero-stress dislocation distributions. More importantly, in this geometric framework we are able to calculate the residual stress fields, assuming that the nonlinear elastic body is incompressible. We derive the governing equations of nonlinear dislocation mechanics covariantly using balance of energy and its covariance. © 2012 Springer-Verlag.

  6. Simulation of structure and annihilation of screw dislocation dipoles

    DEFF Research Database (Denmark)

    Rasmussen, Torben; Vegge, Tejs; Leffers, Torben

    2000-01-01

    Large scale atomistic simulations are used to investigate the properties of screw dislocation dipoles in copper. Spontaneous annihilation is observed for dipole heights less than 1 nm. Equilibrated dipoles of heights larger than 1 nm adopt a skew configuration due to the elastic anisotropy of Cu....... The equilibrium splitting width of the screw dislocations decreases with decreasing dipole height, as expected from elasticity theory. The energy barriers, and corresponding transition states for annihilation of stable dipoles are determined for straight and for flexible dislocations for dipole heights up to 5.......2 nm. In both cases the annihilation is initiated by cross-slip of one of the dislocations. For straight dislocations the activation energy shows a linear dependence on the inverse dipole height, and for flexible dislocations the dependence is roughly linear for the dipoles investigated....

  7. Fostering incidental experiences of nature through green infrastructure planning.

    Science.gov (United States)

    Beery, Thomas H; Raymond, Christopher M; Kyttä, Marketta; Olafsson, Anton Stahl; Plieninger, Tobias; Sandberg, Mattias; Stenseke, Marie; Tengö, Maria; Jönsson, K Ingemar

    2017-11-01

    Concern for a diminished human experience of nature and subsequent decreased human well-being is addressed via a consideration of green infrastructure's potential to facilitate unplanned or incidental nature experience. Incidental nature experience is conceptualized and illustrated in order to consider this seldom addressed aspect of human interaction with nature in green infrastructure planning. Special attention has been paid to the ability of incidental nature experience to redirect attention from a primary activity toward an unplanned focus (in this case, nature phenomena). The value of such experience for human well-being is considered. The role of green infrastructure to provide the opportunity for incidental nature experience may serve as a nudge or guide toward meaningful interaction. These ideas are explored using examples of green infrastructure design in two Nordic municipalities: Kristianstad, Sweden, and Copenhagen, Denmark. The outcome of the case study analysis coupled with the review of literature is a set of sample recommendations for how green infrastructure can be designed to support a range of incidental nature experiences with the potential to support human well-being.

  8. Clinical Characteristics and Prognosis of Incidentally Detected Lung Cancers

    Directory of Open Access Journals (Sweden)

    S. Quadrelli

    2015-01-01

    Full Text Available Objective. To evaluate clinical characteristics and outcomes in incidentally detected lung cancer and in symptomatic lung cancer. Material and Methods. We designed a retrospective study including all patients undergoing pulmonary resection with a curative intention for NSCLC. They were classified into two groups according to the presence or absence of cancer-related symptoms at diagnosis in asymptomatic (ASX—incidental diagnosis—or symptomatic. Results. Of the 593 patients, 320 (53.9% were ASX. In 71.8% of these, diagnosis was made by chest X-ray. Patients in the ASX group were older (P=0.007, had a higher prevalence of previous malignancy (P=0.002, presented as a solitary nodule more frequently (P<0.001, and were more likely to have earlier-stage disease and smaller cancers (P=0.0001. A higher prevalence of incidental detection was observed in the last ten years (P=0.008. Overall 5-year survival was higher for ASX (P=0.001. Median survival times in pathological stages IIIB-IV were not significantly different. Conclusion. Incidental finding of NSCLC is not uncommon even among nonsmokers. It occurred frequently in smokers and in those with history of previous malignancy. Mortality of incidental diagnosis group was lower, but the better survival was related to the greater number of patients with earlier-stage disease.

  9. Incidentally Detected Enhancing Breast Lesions on Chest Computed Tomography

    International Nuclear Information System (INIS)

    Lin, Wen Chiung; Hsu, Hsian He; Yu, Jyh Cherng; Hsu, Giu Cheng; Yu, Cheng Ping; Chang, Tsun Hou; Huang, Guo Shu; Li, Chao Shiang

    2011-01-01

    To evaluate the nature and imaging appearance of incidental enhancing breast lesions detected on a routine contrast-enhanced chest CT. Twenty-three patients with incidental enhancing breast lesions on contrast-enhanced chest CT were retrospectively reviewed. The breast lesions were reviewed by unenhanced and enhanced CT, and evaluated by observing the shapes, margins, enhancement patterns and backgrounds of breast lesions. A histopathologic diagnosis or long-term follow-up served as reference standard. Sixteen (70%) patients had malignant breast lesions and seven (30%) had benign lesions. In 10 patients, the breast lesions were exclusively detected on contrast-enhanced CT. Using unenhanced CT, breast lesions with fi broglandular backgrounds were prone to be obscured (p < 0.001). Incidental primary breast cancer showed an non-significant trend of a higher percentage irregular margin (p = 0.056). All of the four incidental breast lesions with non-mass-like enhancement were proven to be malignant. Routine contrast-enhanced chest CT can reveal sufficient details to allow for the detection of unsuspected breast lesions, in which some cases may be proven as malignant. An irregular margin of incidental enhancing breast lesion can be considered a suggestive sign of malignancy

  10. Closed Reduction of ?Irreducible? Posterolateral Knee Dislocation - A Case Report

    OpenAIRE

    Tateda, Satoshi; Takahashi, Atsushi; Aizawa, Toshimi; Umehara, Jutaro

    2016-01-01

    Introduction: Posterolateral rotary knee dislocation is a rare orthopedic injury that is considered to be irreducible by closed reduction because of soft tissue incarceration. Here, we present a case of posterolateral rotary knee dislocation, which was reduced by closed manipulation. Case report: The patientwas a 33-year-old man who sustained a twisting injury to his right knee that was diagnosed as posterolateral rotary knee dislocation by plain radiographs and the characteristic physical fi...

  11. Static Dislocation Interactions in Thin Channels between Cuboidal Particles

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Antonín; Probst-Hein, M.; Eggeler, G.

    309-310, - (2001), s. 278-282 ISSN 0921-5093. [Dislocations 2000. Gaithersburg, 19.06.2000-22.06.2000] R&D Projects: GA MŠk OC P3.50 Institutional research plan: CEZ:AV0Z2041904 Keywords : discrete dislocation modeling * single crystal superalloys * .gamma./.gamma.'-interface dislocations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.978, year: 2001

  12. Orthodontic Mini-implants for Treatment of Long-term Anterior Dislocation of Temporomandibular Joint

    Directory of Open Access Journals (Sweden)

    Amit Dahiya

    2014-01-01

    Full Text Available Acute dislocation of the temporomandibular joint (TMJ is a relatively common occurrence; chronic long-term dislocation is rare. Variance in the duration of dislocation and anatomical considerations make the treatment for long-standing dislocation complex and controversial. This case report describes a new method of conservative management of a long-standing TMJ dislocation using orthodontic mini-implants.

  13. Influence of fault asymmetric dislocation on the gravity changes

    Directory of Open Access Journals (Sweden)

    Duan Hurong

    2014-08-01

    Full Text Available A fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement along the fractures as a result of earth movement. Large faults within the Earth’s crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, energy release associated with rapid movement on active faults is the cause of most earthquakes. The relationship between unevenness dislocation and gravity changes was studied on the theoretical thought of differential fault. Simulated observation values were adopted to deduce the gravity changes with the model of asymmetric fault and the model of Okada, respectively. The characteristic of unevennes fault momentum distribution is from two end points to middle by 0 according to a certain continuous functional increase. However, the fault momentum distribution in the fault length range is a constant when the Okada model is adopted. Numerical simulation experiments for the activities of the strike-slip fault, dip-slip fault and extension fault were carried out, respectively, to find that both the gravity contours and the gravity variation values are consistent when either of the two models is adopted. The apparent difference lies in that the values at the end points are 17. 97% for the strike-slip fault, 25. 58% for the dip-slip fault, and 24. 73% for the extension fault.

  14. Interfacial dislocation motion and interactions in single-crystal superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Raabe, D. [Max Planck Inst. fur Eisenforshung. Dusseldorf (Germany); Roters, F. [Max Planck Inst. fur Eisenforshung. Dusseldorf (Germany); Arsenlis, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-01

    The early stage of high-temperature low-stress creep in single-crystal superalloys is characterized by the rapid development of interfacial dislocation networks. Although interfacial motion and dynamic recovery of these dislocation networks have long been expected to control the subsequent creep behavior, direct observation and hence in-depth understanding of such processes has not been achieved. Incorporating recent developments of discrete dislocation dynamics models, we simulate interfacial dislocation motion in the channel structures of single-crystal superalloys, and investigate how interfacial dislocation motion and dynamic recovery are affected by interfacial dislocation interactions and lattice misfit. Different types of dislocation interactions are considered: self, collinear, coplanar, Lomer junction, glissile junction, and Hirth junction. The simulation results show that strong dynamic recovery occurs due to the short-range reactions of collinear annihilation and Lomer junction formation. The misfit stress is found to induce and accelerate dynamic recovery of interfacial dislocation networks involving self-interaction and Hirth junction formation, but slow down the steady interfacial motion of coplanar and glissile junction forming dislocation networks. The insights gained from these simulations on high-temperature low-stress creep of single-crystal superalloys are also discussed.

  15. Dislocation kinetics and the acoustic-wave approximation for liquids

    International Nuclear Information System (INIS)

    Stout, R.B.

    1983-03-01

    A dislocation-dependent model for liquids describes the lattice deformation and the fluidity deformation as additive deformations. The lattice deformation represents distortions of an atom's potential energy structure and is a recoverable deformation response. The fluidity deformation represents discontinuous repositioning of atoms by dislocation kinetics in the lattice structure and is a nonrecoverable deformation response. From this model, one concludes that in liquids the acoustic-wave approximation is a description of a recoverable oscillation deformation that has dissipation because of dislocation kinetics. Other more-complex waves may exist, but such waves would rapidly disappear because of the small thermodynamic potential for dislocation kinetics in liquids

  16. Fabrication of mesoscopic floating Si wires by introducing dislocations

    International Nuclear Information System (INIS)

    Motohashi, Mitsuya; Shimizu, Kazuya; Niwa, Masaaki; Suzuki, Toshiaki

    2014-01-01

    We fabricated a mesoscopic Si wire by introducing dislocations in a silicon wafer before HF anodization. The dislocations formed along the (111) crystal plane. The outline of the dislocation line was an inverted triangle. The resulting wire floated on a bridge girder and had a hybrid structure consisting of a porous layer and crystalline Si. The cross section of the wire had an inverted triangle shape. The wire formation mechanism is discussed in terms of carrier transport, crystal structure, and dislocation formation during anodization. (paper)

  17. Fabrication of mesoscopic floating Si wires by introducing dislocations

    Science.gov (United States)

    Motohashi, Mitsuya; Shimizu, Kazuya; Suzuki, Toshiaki; Niwa, Masaaki

    2014-12-01

    We fabricated a mesoscopic Si wire by introducing dislocations in a silicon wafer before HF anodization. The dislocations formed along the (111) crystal plane. The outline of the dislocation line was an inverted triangle. The resulting wire floated on a bridge girder and had a hybrid structure consisting of a porous layer and crystalline Si. The cross section of the wire had an inverted triangle shape. The wire formation mechanism is discussed in terms of carrier transport, crystal structure, and dislocation formation during anodization.

  18. Harmonic oscillator in an elastic medium with a spiral dislocation

    Science.gov (United States)

    Maia, A. V. D. M.; Bakke, K.

    2018-02-01

    We investigate the behaviour of a two-dimensional harmonic oscillator in an elastic medium that possesses a spiral dislocation (an edge dislocation). We show that the Schrödinger equation for harmonic oscillator in the presence of a spiral dislocation can be solved analytically. Further, we discuss the effects of this topological defect on the confinement to a hard-wall confining potential. In both cases, we analyse if the effects of the topology of the spiral dislocation gives rise to an Aharonov-Bohm-type effect for bound states.

  19. Dislocation and its recurrence after revision total hip arthroplasty.

    Science.gov (United States)

    Yoshimoto, Kensei; Nakashima, Yasuharu; Yamamoto, Takuaki; Fukushi, Jun-Ichi; Motomura, Goro; Ohishi, Masanobu; Hamai, Satoshi; Iwamoto, Yukihide

    2016-08-01

    Dislocation is a leading cause of failure after revision total hip arthroplasty (THA). This study was conducted to examine the risk factors for dislocation as well as their recurrence after revision THA. We retrospectively reviewed 178 revision THAs in 162 patients between 1998 and 2013. The mean patient age was 65.2 years at operation and the mean follow-up period was 6.7 years. Multivariate logistic regression was performed to identify risk factors for dislocation, and further comparison was made between patients with single and recurrent dislocations. Sixteen hips in 15 patients (9.0 %) dislocated at a mean of 9.1 months (range, 0-83 months) after revision THA. Multivariate analysis identified advanced age (odds ratio [OR] = 2.94/10 years) and osteonecrosis of the femoral head (OR = 7.71) as the independent risk factors for any dislocations. Risk factors for recurrent dislocations, which were observed in eight hips (50 %), were later dislocations (≥4 months) and lower BMI. Dislocation is a serious problem after revision THA with multiple risk factors. Although our findings were limited to revision THAs done through posterolateral approach, recognition of these factors is helpful in patient education and surgical planning.

  20. Dislocations and torsion in graphene and related systems

    International Nuclear Information System (INIS)

    Juan, Fernando de; Cortijo, Alberto; Vozmediano, Maria A.H.

    2010-01-01

    A continuum model to study the influence of dislocations on the electronic properties of condensed matter systems is described and analyzed. The model is based on a geometrical formalism that associates a density of dislocations with the torsion tensor and uses the technique of quantum field theory in curved space. When applied to two-dimensional systems with Dirac points like graphene we find that dislocations couple in the form of vector gauge fields similar to these arising from curvature or elastic strain. We also describe the ways to couple dislocations to normal metals with a Fermi surface.

  1. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Horsewell, Andy

    1986-01-01

    High-purity (99. 999%) and fully annealed copper specimens have been irradiated in the DR-3 reactor at Riso to doses of 1 multiplied by 10**2**2 and 5 multiplied by 10**2**2 neutrons (fast)m** minus **2(2 multiplied by 10** minus **3 dpa and 1 multiplied by 10** minus **2 dpa, respectively...... were distributed between these walls. The dislocation walls were practically free of voids and generally had a void-denuded zone along them. The density of dislocations (loops and segments) was very low in the region containing voids (i. e. between the dislocation walls). Even with this low dislocation...

  2. Traumatic Anterior Dislocation of Hip in a Child- Case Report

    Directory of Open Access Journals (Sweden)

    S Ahmad

    2015-03-01

    Full Text Available Traumatic hip dislocation in children is relatively rare accounting for about 5% of all hip dislocations. Most of the hip dislocations seen in children are of the posterior type but the much rarer anterior and anterior-inferior (obturator types have also been described. We present the case of an eight years old girl with an obturator type of hip dislocation following trivial trauma. She was treated with closed reduction and immobilisation in skin traction for three weeks. She was followed up closely for one year and did not develop any complications during that period.

  3. Investigation of slip transfer across HCP grain boundaries with application to cold dwell facet fatigue

    International Nuclear Information System (INIS)

    Zheng, Zebang; Balint, Daniel S.; Dunne, Fionn P.E.

    2017-01-01

    This paper addresses the role of grain boundary slip transfer and thermally-activated discrete dislocation plasticity in the redistribution of grain boundary stresses during cold dwell fatigue in titanium alloys. Atomistic simulations have been utilised to calculate the grain boundary energies for titanium with respect to the misorientation angles. The grain boundary energies are utilised within a thermally-activated discrete dislocation plasticity model incorporating slip transfer controlled by energetic and grain boundary geometrical criteria. The model predicts the grain size effect on the flow strength in Ti alloys. Cold dwell fatigue behaviour in Ti-6242 alloy is investigated and it is shown that significant stress redistribution from soft to hard grains occurs during the stress dwell, which is observed both for grain boundaries for which slip transfer is permitted and inhibited. However, the grain boundary slip penetration is shown to lead to significantly higher hard-grain basal stresses near the grain boundary after dwell, thus exacerbating the load shedding stress compared to an impenetrable grain boundary. The key property controlling the dwell fatigue response is argued to remain the time constant associated with the thermal activation process for dislocation escape, but the slip penetrability is also important and exacerbates the load shedding. The inclusion of a macrozone does not significantly change the conclusions but does potentially lead to the possibility of a larger initial facet.

  4. Role of fluttering dislocations in the thermal interface resistance between a silicon crystal and plastic solid 4He

    Science.gov (United States)

    Amrit, Jay; Ramiere, Aymeric; Volz, Sebastian

    2018-01-01

    A quantum solid (solid 4He) in contact with a classical solid defines a new class of interfaces. In addition to its quantum nature, solid 4He is indeed a very plastic medium. We examine the thermal interface resistance upon solidification of superfluid 4He in contact with a silicon crystal surface (111) and show that dislocations play a crucial role in the thermal interface transport. The growth of solid 4He and the measurements are conducted at the minimum of the melting curve of helium (0.778 K and ˜25 bar ). The results display a first-order transition in the Kapitza resistance from a value of RK ,L=(80 ±8 ) c m2K /W at a pressure of 24.5 bar to a value of RK ,S=(41.7 ±8 ) c m2K /W after the formation of solid helium at ˜25.2 bar . The drop in RK ,S is only of a factor of ˜2 , although transverse phonon modes in solid 4He now participate in heat transmission at the interface. We provide an explanation for the measured RK ,S by considering the interaction of thermal phonons with vibrating dislocations in solid 4He. We demonstrate that this mechanism, also called fluttering, induces a thermal resistance RF l∝NdT-6 , where T is the temperature and Nd is the density of dislocations. We estimate that for dislocation densities on the order of ˜107c m-2 , RF l predominates over the boundary resistance RK ,S. These fundamental findings shed light on the role of dislocations and provide a quantitative explanation for previous experiments which showed no measurable change in the Kapitza resistance between Cu and superfluid 4He upon solidification of the latter. This demonstrates the possibility of using dislocations as an additional means to tailor thermal resistances at interfaces, formed especially with a plastic material.

  5. Patients' views on incidental findings from clinical exome sequencing

    Directory of Open Access Journals (Sweden)

    Kristin E. Clift

    2015-03-01

    Full Text Available This article characterizes the opinions of patients and family members of patients undergoing clinical genomic-based testing regarding the return of incidental findings from these tests. Over sixteen months, we conducted 55 in-depth interviews with individuals to explore their preferences regarding which types of results they would like returned to them. Responses indicate a diversity of attitudes toward the return of incidental findings and a diversity of justifications for those attitudes. The majority of participants also described an imperative to include the patient in deciding which results to return rather than having universal, predetermined rules governing results disclosure. The results demonstrate the importance of a patient centered-approach to returning incidental findings.

  6. 78 FR 15737 - Incidental Take Permit Amendment and Supplemental Environmental Assessment for Wind Energy...

    Science.gov (United States)

    2013-03-12

    ...] Incidental Take Permit Amendment and Supplemental Environmental Assessment for Wind Energy Development... of a revised habitat conservation plan (revised HCP) and accompanying documents for wind energy... of Puerto Rican crested toad (Peltophryne lemur) incidental to the previously authorized wind energy...

  7. Percutaneous osteosynthesis of Galeazzi fracture-dislocation.

    Science.gov (United States)

    Gadegone, Wasudeo M; Salphale, Yogesh; Magarkar, Ds

    2010-10-01

    A Galeazzi fracture is defined as a fracture of the radius associated with dislocation of the distal radio-ulnar joint (DRUJ). The conventional surgical technique of nailing does not give enough stability and open reduction, internal fixation with the plate is associated with numerous complications. The stacked nailing for the management of these injuries provides adequate stability, maintains the relationship of the DRUJ and promotes uneventful union by closed technique. The purpose of this study is to evaluate the results of simple, user-friendly, low cost elastic stacked nailing for the management of Galeazzi fracture dislocation. We treated 22 young adults with fresh Galeazzi fracture-dislocation of the forearm, from January 2004 to January 2008, by percutaneous fixation of fracture by stacked elastic nailing at our institute. There were 19 males and three females and the age group ranged from 20-56 years (average 35 years). Surgery was performed within 48 to 72 hours under the guidance of image intensifier. Medullary cavity was filled with two elastic titanium nails having unequal lengths and diameter. One nail acts as a reduction nail and the other acts as a stabilizing nail. The results were evaluated using Mikic criteria based on union, alignment, relationship of the DRUJ, and movements at the inferior radio ulnar joint, elbow and wrist. In six cases, following radiological union, nails in the radius were extracted between six to nine months after operation because of discomfort complained by the patient at site of insertion. After one year follow-up, 18 patients had excellent, four had fair results. Closed reduction and internal fixation of Galeazzi fracture by two elastic rods re-establishes the normal relationship of the fractured fragments and the DRUJ without repair of the ligaments. The stability is achieved by the flexibility and elasticity of the nails, crowding of the medullary canal and anchorage they gain in the radial diaphysis. Elastic nailing

  8. Bilateral Hip Dislocation in Unrestrained Driver

    Directory of Open Access Journals (Sweden)

    Samer Assaf

    2017-09-01

    Full Text Available History of present illness: A 24-year-old male was brought in by paramedics status post motor vehicle collision (MVC into an electric pole and tree at high speed. The patient was an unrestrained driver who required extrication. The patient complained of left hip pain, left foot pain, and difficulty extending his bilateral lower extremities. He denied numbness or tingling to his lower extremities. The patient had normal vitals; his bilateral lower extremities were held in flexion at the hips, but otherwise had no obvious injuries. The patient’s pelvis was stable with palpable distal pulses and intact motor and sensory function of his distal lower extremities. Significant findings: The initial radiograph of the pelvis revealed bilateral hip dislocations. Small bony fragments were noted in the right hip joint, suggestive of an underlying fracture. The sacroiliac joints and the pelvic ring were intact. In the emergency department, bilateral hip reductions were performed using the Captain Morgan technique.1 The post-reduction film showed reduction of the bilateral hip dislocations with extensive comminuted and displaced fractures of the right and left acetabula. Discussion: Bilateral hip dislocations are extremely rare, occurring in only 1% of all hip dislocations,2 and require immense force, typically occurring in MVCs (74%.3-7 Associated injuries include fracture of the acetabulum or femoral head, sciatic nerve damage, and obstruction of the blood supply to the femoral head.8 X-ray imaging and CT scans are used to assess the injury and to detect intra-articular fragments.3 Definitive treatment is achieved by closed reduction if possible; otherwise open reduction is utilized.9 Post-reduction therapy includes a non-weight-bearing period of time. Complications include avascular necrosis of the femoral head, osteonecrosis, and posttraumatic arthritis, the occurrence of which can be decreased by early reduction.4,10-12 This patient underwent bilateral

  9. Humeral shaft fracture with ipsilateral shoulder dislocation

    Directory of Open Access Journals (Sweden)

    Behera Prateek

    2014-02-01

    Full Text Available 【Abstract】Although fracture of the humeral shaft or dislocation of the shoulder joint is a common injury, a simutaneous injury is rare. We present such a case combined with head injury which took precedence over the skeletal injuries. The postoperative rehabilitation was slowed down by the head injury. This case report makes us aware of some problems when managing the patient with this rare injury and helps us understand the management options better. Also the need for proper follow-up and rehabilitation is emphasized.

  10. Incidental findings in musculoskeletal radiology; Zufallsbefunde in der muskuloskeletalen Radiologie

    Energy Technology Data Exchange (ETDEWEB)

    Wuennemann, F.; Rehnitz, C.; Weber, M.A. [Universitaetsklinikum Heidelberg, Klinik fuer Diagnostische und Interventionelle Radiologie, Heidelberg (Germany)

    2017-04-15

    Increasing numbers of conventional X-rays, computed tomography and magnetic resonance imaging in the inpatient, outpatient and scientific routine leads to an increasing number of incidental findings. The correct interpretation of these incidental findings with respect to the relevance and the evaluation concerning further work-up is an important task of radiologists. Description of common incidental findings in musculoskeletal imaging and their clinical classification. A PubMed literature search was performed using the following terms: incidental findings, population-based imaging, musculoskeletal imaging, non-ossifying fibroma, enchondroma, osteodystrophia deformans, chondrosarcoma, fibrous dysplasia, simple bone cyst, unicameral bone cyst, solitary bone cyst, aneurysmal bone cyst, vertebral hemangioma, bone island, osteopoikilosis, Tarlov cyst and diffuse idiopathic skeletal hyperostosis (DISH). Incidental findings are observed in up to 40% of imaging procedures. In up to 6% these incidental findings involve the skeletal system. Common incidental findings are discussed and their clinical relevance is explained. (orig.) [German] Mit steigender Menge an konventionellen Roentgen- sowie CT- und MRT-Bildern im stationaeren, ambulanten und wissenschaftlichen Alltag steigt unweigerlich auch die Zahl der Zufallsbefunde. Die korrekte Einordnung bzgl. deren Relevanz, ob eine weitere Abklaerung notwendig ist oder nicht, stellt eine wichtige Aufgabe des Radiologen dar. Vorstellung haeufiger Zufallsbefunde des muskuloskeletalen Systems und deren klinische Einordnung. Pubmed-Literaturrecherche zu den Stichworten ''incidental findings'', ''population-based imaging'', ''musculoskeletal imaging'', ''non-ossifying fibroma'', ''enchondroma'', ''osteodysthrophia deformans'', ''chondrosarcoma'', ''fibrous dysplasia'', &apos

  11. Research malpractice and the issue of incidental findings.

    Science.gov (United States)

    Milstein, Alan C

    2008-01-01

    Human subject research involving brain imaging is likely to reveal significant incidental findings of abnormal brain morphology. Because of this fact and because of the fiduciary relationship between researcher and subject, board-certified or board-eligible radiologists should review the scans to look for any abnormality, the scans should be conducted in accordance with standard medical practice for reviewing the clinical status of the whole brain, and the informed consent process should disclose the possibility that incidental findings may be revealed and what consequences will follow. In the event such findings are revealed, qualified physicians should explain to the subject the significance of the findings and the alternatives available.

  12. Partial spline score test to determine if tumors are incidental

    International Nuclear Information System (INIS)

    Griffith, W.C.

    1994-01-01

    A primary consideration in many rodent bioassays is whether a tumor observed in an animal has affected its life span. When tumors are incidental, the natural death times can be regarded as random sampling times unrelated to the presence of the tumor. In this case, animals dying from natural causes and those sacrificed can be combined to estimate the prevalence p(t) of the tumors in the living animals. When tumors are incidental, the tumor incidence rate, λ T (t), is related to the prevalence by λ T (t) = p(t) 1 - p(t) , where p(t) is the derivative of the prevalence

  13. Influence of fraction of high angle boundaries on the mechanical behavior of an ultrafine grained Al-Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kapoor, R.; Kumar, N. [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Mishra, R.S., E-mail: rsmishra@mst.edu [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Huskamp, C.S.; Sankaran, K.K. [Boeing Research and Technology, Boeing Company, St. Louis, MO 63166 (United States)

    2010-07-25

    The mechanical behavior of ultrafine grained AA5052 processed through different techniques-rolled, annealed, friction stir processed (FSP) and equal channel angular pressed (ECAP)-were compared and correlated with microstructure. The microstructure was characterized using electron back scattered diffraction to obtain the boundary spacing, the fraction of high angle boundaries and to estimate the dislocation density from local misorientations. Both FSP and ECAP conditions had ultrafine boundary spacing, but the fraction of high angle boundaries was larger for the FSP condition. Tensile deformation carried out at 297 K and 10{sup -3} s{sup -1} showed a lower work-hardening rate and recovery rate for FSP as compared to the ECAP condition. It was inferred that low angle boundaries are more effective sinks for dislocations. When comparing differently processed materials, the strength, ductility and work-hardening behavior correlate better with the fraction of high angle boundaries than the boundary spacing.

  14. Bleeding boundaries

    DEFF Research Database (Denmark)

    Jørgensen, Kristian Møller; Petersen, Michael Nebeling

    2018-01-01

    Hook-up apps such as Grindr and Scruff have become important sites for the negotiation of sex between men, in that they shape the ways intimacy cultures are practised and become visible (Mowlabocus, 2010; Race, 2014; Duguay et al., 2016). While such apps enable different intimacy cultures......, they also come paired with anxieties. In the epigraph the interview participant James1 expresses concerns about the how the hook-up app Scruff might restructure the boundaries of privacy and make him vulnerable to exposure. Such technological ambivalence is central to domestication theory, which focuses...

  15. Breaking Boundaries

    DEFF Research Database (Denmark)

    . As a fundamental human experience, liminality transmits cultural practices, codes, rituals, and meanings in-between aggregate structures and uncertain outcomes. As a methodological tool it is well placed to overcome disciplinary boundaries, which often direct attention to specific structures or sectors of society....... Its capacity to provide explanatory accounts of seemingly unstructured situations provides an opportunity to link experience-based and culture-oriented approaches not only to contemporary problems but also to undertake comparisons across historical periods. From a perspective of liminality...

  16. Boundary issues

    Science.gov (United States)

    Townsend, Alan R.; Porder, Stephen

    2011-03-01

    What is our point of no return? Caesar proclaimed 'the die is cast' while crossing the Rubicon, but rarely does modern society find so visible a threshold in our continued degradation of ecosystems and the services they provide. Humans have always used their surroundings to make a living— sometimes successfully, sometimes not (Diamond 2005)—and we intuitively know that there are boundaries to our exploitation. But defining these boundaries has been a challenge since Malthus first prophesied that nature would limit the human population (Malthus 1798). In 2009, Rockström and colleagues tried to quantify what the 6.8 billion (and counting) of us could continue to get away with, and what we couldn't (Rockström et al 2009). In selecting ten 'planetary boundaries', the authors contend that a sustainable human enterprise requires treating a number of environmental thresholds as points of no return. They suggest we breach these Rubicons at our own peril, and that we've already crossed three: biodiversity loss, atmospheric CO2, and disruption of the global nitrogen (N) cycle. As they clearly hoped, the very act of setting targets has provoked scientific inquiry about their accuracy, and about the value of hard targets in the first place (Schlesinger 2009). Such debate is a good thing. Despite recent emphasis on the science of human-ecosystem interactions, understanding of our planetary boundaries is still in its infancy, and controversy can speed scientific progress (Engelhardt and Caplan 1987). A few weeks ago in this journal, Carpenter and Bennett (2011) took aim at one of the more controversial boundaries in the Rockström analysis: that for human alteration of the global phosphorus (P) cycle. Rockström's group chose riverine P export as the key indicator, suggesting that humans should not exceed a value that could trigger widespread marine anoxic events—and asserting that we have not yet crossed this threshold. There are defensible reasons for a marine

  17. Non-equilibrium grain boundaries in titanium nanostructured by severe plastic deformation: Computational study of sources of material strengthening

    DEFF Research Database (Denmark)

    Liu, Hongsheng; Mishnaevsky, Leon; Pantleon, Wolfgang

    2014-01-01

    and properties of the grain boundary (GB) phase have been carried out. The effect of different degrees of deviation from the equilibrium state of the grain boundaries (GBs) on the mechanical behaviour of nanostructured Ti have been investigated using the combined composite/dislocation dynamics based model....... In particular, the effects of different diffusion coefficients in the GB phase, of a high initial dislocation density in the grain boundaries, as well as of atomic scale precipitates are investigated for affecting the deformation behaviour of UFG or nanostructured Ti. © 2013 Elsevier B.V. All rights reserved....

  18. Model of subgrain boundaries formation in matrix of M-MeC eutedtic alloys

    International Nuclear Information System (INIS)

    Bokshtejn, S.Z.; Vasilenok, L.B.; Kishkin, S.T.; Razumovskij, I.M.

    1982-01-01

    A model of subgrain boundary formation and, therefore, formation of substructure in matrix of M-MeC alloy prepared by the method of directed crystallization where M-nickel-base or cobalt-base solid solution, MeC-carbide of tantalum, niobium and hafnium is suggested. The model is based on the concept of dislocation replacement from interfaces into the matrix volume. It is stated that an essential difference of thermal expansion coefficients, a definite ratio of lattice periods of hardening phase and matrix and the presence of a dislocation network on the interface of ordered phases are the important factors determining a possibility of subgrain boundary formation

  19. A Review of Effect of Different Tasks on Incidental Vocabulary Acquisition

    Science.gov (United States)

    Liu, Chen L.

    2015-01-01

    Studies of incidental vocabulary acquisition in second language learning have got more and more attention both at home and abroad. By first introducing the definition and theoretical foundations of incidental vocabulary acquisition, this paper reviews empirical studies of effect of different tasks on incidental vocabulary acquisition and points…

  20. 50 CFR 216.107 - Incidental harassment authorization for Arctic waters.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Incidental harassment authorization for Arctic waters. 216.107 Section 216.107 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL... Incidental to Specified Activities § 216.107 Incidental harassment authorization for Arctic waters. (a...

  1. 76 FR 12751 - Endangered and Threatened Wildlife and Plants; Receipt of Applications for Incidental Take...

    Science.gov (United States)

    2011-03-08

    ... Incidental Take Permits; Availability of Proposed Low- Effect Habitat Conservation Plan and Associated... the availability of incidental take permit (ITP) applications and a Habitat Conservation Plan (HCP... incidental to land preparation for the extension and paving of a road, the construction of a fellowship hall...

  2. 75 FR 20344 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Rocket Launches from...

    Science.gov (United States)

    2010-04-19

    ... Marine Mammals Incidental to Rocket Launches from Kodiak, AK AGENCY: National Marine Fisheries Service... (Eumetopias jubatus) and Pacific harbor seals (Phoca vitulina richardsi) incidental to rocket launches from... Steller sea lions and harbor seals, by harassment, incidental to rocket launches at KLC, became effective...

  3. The Einsteinian T(3)-gauge approach and the stress tensor of the screw dislocation in the second order: avoiding the cut-off at the core

    International Nuclear Information System (INIS)

    Malyshev, C

    2007-01-01

    A translational gauge approach of the Einstein type is proposed for obtaining the stresses that are due to non-singular screw dislocation. The stress distribution of the second order around the screw dislocation is classically known for the hollow circular cylinder with traction-free external and internal boundaries. The inner boundary surrounds the dislocation's core, which is not captured by the conventional solution. The present gauge approach enables us to continue the classically known quadratic stresses inside the core. The gauge equation is chosen in the Hilbert-Einstein form, and it plays the role of non-conventional incompatibility law. The stress function method is used, and it leads to the modified stress potential given by two constituents: the conventional one, say, the 'background' and a short-ranged gauge contribution. The latter just causes additional stresses, which are localized. The asymptotic properties of the resulting stresses are studied. Since the gauge contributions are short-ranged, the background stress field dominates sufficiently far from the core. The outer cylinder's boundary is traction-free. At sufficiently moderate distances, the second-order stresses acquire regular continuation within the core region, and the cut-off at the core does not occur. Expressions for the asymptotically far stresses provide self-consistently new length scales dependent on the elastic parameters. These lengths could characterize an exteriority of the dislocation core region

  4. Dislocation-defect interactions in nuclear reactor pressure-vessel steels investigated by means of internal friction

    International Nuclear Information System (INIS)

    Van Ouytsel, K.; Fabry, A.; Schaller, R.

    1999-01-01

    Full text: A study of pressure-vessel steel embrittlement by means of temperature-dependent and amplitude-dependent internal friction has been carried out within the framework of commercial surveillance of nuclear reactor components. An inverted torsion pendulum operating at approximately 1 Hz has been employed to study JRQ, Doel-I-II and Doel IV pressure-vessel steels in unirradiated, thermally aged, neutron-irradiated, and annealed conditions. The temperature-dependent experiments evidence a reduction in the dislocation mobility as a result of neutron irradiation and prove that the technique is sensitive to thermal ageing and annealing involving changes in the dislocation mobility and type of dislocation-defect interaction. Amplitude-dependent results reveal a critical amplitude which can be related to the yield stress of the material in tension and corresponds well to a two-component model of the yield stress encompassing contributions of a short-range nature, such as the Peierls barrier to dislocation movement, and of long-range character, such as copper-rich precipitation and grain boundary segregation. The applicability of the non-destructive internal-friction technique to commercial steel programmes is highlighted. (author)

  5. Interaction between interstitial atoms and 1/2 (110) edge dislocations, and its influence on the Peierls stress

    International Nuclear Information System (INIS)

    de Hosson, J.T.M.

    1976-01-01

    The positions of the metal atoms around a 1 / 2 (111) (110) edge dislocation in Mo and W are calculated using the Wilson-Johnson potentials. The boundary conditions are given by anisotropic elasticity theory. After the lattices have been relaxed the potential energy of a He atom was calculated for a grid of positions within a block around the dislocation core, which extends over six planes in the (112) direction. The He-metal potential, also developed by Johnson and Wilson was used to calculate the position with maximum energy gain for a He atom. The binding energies of the He atom in the dislocated lattice for Mo and W were 1.55 eV and 1.53 eV, respectively. The second part of the investigation concerns the Peierls stresses for a 1 / 2 (111) (110) edge dislocation in α-Fe, with and without a carbon atom. The Peierls energy and stress are calculated for this slip-system based on the method originally used by Nabarro. The Peierls stresses (at zero absolute temperature) for the lattice with and without a carbon atom, are 0.006 μ and 0.009 μ, respectively. These calculations were carried out utilizing the Wilson-Johnson potential for the Fe-Fe interaction and the Johnson potential was used for the Fe-C interaction

  6. Grain boundary structure and solute segregation in titanium-doped sapphire bicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Seth Thomas [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    Solute segregation to ceramic grain boundaries governs material processing and microstructure evolution, and can strongly influence material properties critical to engineering performance. Understanding the evolution and implications of grain boundary chemistry is a vital component in the greater effort to engineer ceramics with controlled microstructures. This study examines solute segregation to engineered grain boundaries in titanium-doped sapphire (Al2O3) bicrystals, and explores relationships between grain boundary structure and chemistry at the nanometer scale using spectroscopic and imaging techniques in the transmission electron microscope (TEM). Results demonstrate dramatic changes in solute segregation stemming from small fluctuations in grain boundary plane and structure. Titanium and silicon solute species exhibit strong tendencies to segregate to non-basal and basal grain boundary planes, respectively. Evidence suggests that grain boundary faceting occurs in low-angle twis t boundaries to accommodate nonequilibrium solute segregation related to slow specimen cooling rates, while faceting of tilt grain boundaries often occurs to expose special planes of the coincidence site lattice (CSL). Moreover, quantitative analysis of grain boundary chemistry indicates preferential segregation of charged defects to grain boundary dislocations. These results offer direct proof that static dislocations in ionic materials can assume a net charge, and emphasize the importance of interactions between charged point, line, and planar defects in ionic materials. Efforts to understand grain boundary chemistry in terms of space charge theory, elastic misfit and nonequilibrium segregation are discussed for the Al2O3 system.

  7. Grain boundary structure and solute segregation in titanium-doped sapphire bicrystals

    International Nuclear Information System (INIS)

    Taylor, Seth T.

    2002-01-01

    Solute segregation to ceramic grain boundaries governs material processing and microstructure evolution, and can strongly influence material properties critical to engineering performance. Understanding the evolution and implications of grain boundary chemistry is a vital component in the greater effort to engineer ceramics with controlled microstructures. This study examines solute segregation to engineered grain boundaries in titanium-doped sapphire (Al2O3) bicrystals, and explores relationships between grain boundary structure and chemistry at the nanometer scale using spectroscopic and imaging techniques in the transmission electron microscope (TEM). Results demonstrate dramatic changes in solute segregation stemming from small fluctuations in grain boundary plane and structure. Titanium and silicon solute species exhibit strong tendencies to segregate to non-basal and basal grain boundary planes, respectively. Evidence suggests that grain boundary faceting occurs in low-angle twis t boundaries to accommodate nonequilibrium solute segregation related to slow specimen cooling rates, while faceting of tilt grain boundaries often occurs to expose special planes of the coincidence site lattice (CSL). Moreover, quantitative analysis of grain boundary chemistry indicates preferential segregation of charged defects to grain boundary dislocations. These results offer direct proof that static dislocations in ionic materials can assume a net charge, and emphasize the importance of interactions between charged point, line, and planar defects in ionic materials. Efforts to understand grain boundary chemistry in terms of space charge theory, elastic misfit and nonequilibrium segregation are discussed for the Al2O3 system

  8. Temporomandibular joint dislocation in an epileptic and mentally ...

    African Journals Online (AJOL)

    Temporomandibular joint (TMJ) dislocation is defined as an excessive forward movement of the condyle beyond the articular eminence with complete separation of articular surfaces and fixation in that position.' Theories regarding the pathogenesis of TMJ dislocation propose laxity of TMJ ligaments or capsule, excessive ...

  9. Dislocation multiplication rate in the early stage of germanium plasticity

    Czech Academy of Sciences Publication Activity Database

    Fikar, J.; Dupas, Corinne; Kruml, Tomáš; Jacques, A.; Martin, J. L.

    400-401, - (2005), s. 431-434 ISSN 0921-5093. [Dislocations 2004. La Colle-sur-Loup, 13.09.2004-17.09.2004] Institutional research plan: CEZ:AV0Z2041904 Keywords : dislocation multiplication * germanium * constitutive modelling Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.347, year: 2005

  10. Management of neglected traumatic posterior dislocations of the hip ...

    African Journals Online (AJOL)

    Within a period of six months, three men were admitted following falls which had occurred more than one week previously. They had all sustained minor trauma but directly after the injury they were unable to bear weight on the affected limb. All three had Grade 1 posterior dislocations of the hip. Although the dislocation had ...

  11. Ipsilateral dislocation of the shoulder and elbow: A case report

    African Journals Online (AJOL)

    Pr KODO

    There was deformity and painful swelling of the right shoulder and elbow. No neurovascular deficit was found and other clinical. findings were normal. Plain radiograph revealed ipsilateral anterior shoulder and posterior elbow dislocations (Fig 1). Under general anesthesia, the dislocations were readily reduced by closed.

  12. Dislocated ankle fracture complicated by near total distal ischaemia

    Science.gov (United States)

    Duygun, Fatih; Sertkaya, Omer; Aldemir, Cengiz; Dogan, Ali

    2013-01-01

    Total arterial ischaemia is rarely seen following a dislocated ankle fracture but if it does and intervention is not made, it can lead to serious morbidity. We present a 39-year-old woman with almost total occlusion in the arteria tibialis and arteria dorsalis pedis following a dislocated ankle fracture as a result of a bicycle fall. PMID:24248319

  13. Perineal anterior dislocation of the hip with avulsion fracture of ...

    African Journals Online (AJOL)

    Traumatic anterior dislocation of the hip is rare even in children. Very uncommon also is the perineal variant of the inferior type of anterior dislocation with concomitant avulsion fracture of the greater trochanter. We report such a case highlighting the peculiarity of its management. No similar case of triumvirate injury of the hip ...

  14. Results of open reduction for neglected elbow dislocations in adult ...

    African Journals Online (AJOL)

    Objective: To present the results of open reduction of neglected elbow dislocations using a consistent surgical protocol. Patients and methods: Between 2000 and 2005 eight patients with neglected elbow dislocations were operated on using the Speed\\'s posterior approach with lengthening of the triceps by V-Y ...

  15. Isolated posterior dislocation of the radial head in an adult.

    Directory of Open Access Journals (Sweden)

    Negi A

    1992-07-01

    Full Text Available Isolated posterior dislocation of the radial head was detected on X-ray in a patient following a vehicular accident. Such a dislocation without an associated fracture is extremely rare in adults. Immobilization of the elbow in full pronation and 90 degrees flexion for 4 weeks normalized the position of the head of the radius.

  16. Pediatric open elbow dislocation without fracture: A case report

    Directory of Open Access Journals (Sweden)

    Gökhan Polat

    2014-01-01

    CONCLUSION: Pediatric elbow dislocations are rare injuries and the management of these injuries can be technically demanding due to concurrent neurovascular injuries. An open dislocation without fracture is very rare and it should be treated with immediate intervention, an effective teamwork and good rehabilitation.

  17. A Monte Carlo adapted finite element method for dislocation ...

    Indian Academy of Sciences (India)

    Mean and standard deviation values, as well as probability density function of ground surface responses due to the dislocation are computed. Based on analytical and numerical calculation of dislocation, two approaches of Monte Carlo simulations are proposed. Various comparisons are examined to illustrate the capability ...

  18. Superior dislocation hip with anterior column acetabular fracture ...

    African Journals Online (AJOL)

    Superior variety of anterior dislocation of the hip is a rare injury. Its occurrence with acetabular fractures has been documented infrequently. We report a case of superior dislocation of the hip with anterior column acetabular fracture. Open reduction of the hip and internal fixation of the fracture was carried out using a twin ...

  19. Method to reduce dislocation density in silicon using stress

    Science.gov (United States)

    Buonassisi, Anthony; Bertoni, Mariana; Argon, Ali; Castellanos, Sergio; Fecych, Alexandria; Powell, Douglas; Vogl, Michelle

    2013-03-05

    A crystalline material structure with reduced dislocation density and method of producing same is provided. The crystalline material structure is annealed at temperatures above the brittle-to-ductile transition temperature of the crystalline material structure. One or more stress elements are formed on the crystalline material structure so as to annihilate dislocations or to move them into less harmful locations.

  20. Traumatic posterior dislocation of the hip: distribution and severity of ...

    African Journals Online (AJOL)

    These injuries take precedence in the emergency care of patients with posterior dislocation of the hip. The role of public enlightment on road safety measures cannot be over-emphasized and a case is made for training of the populace in essential basic life support. Keywords: Posterior hip dislocation; associated injuries; ...

  1. Rows of Dislocation Loops in Aluminium Irradiated by Aluminium Ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.

    1967-01-01

    Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along <110 > directions. ©1967 The American Institute of Physics......Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along directions. ©1967 The American Institute of Physics...

  2. Self-force on dislocation segments in anisotropic crystals

    International Nuclear Information System (INIS)

    Fitzgerald, S P; Aubry, S

    2010-01-01

    A dislocation segment in a crystal experiences a 'self-force', by virtue of the orientation dependence of its elastic energy. If the crystal is elastically isotropic, this force is manifested as a couple acting to rotate the segment toward the lower energy of the pure screw orientation (i.e. acting to align the dislocation line with its Burgers vector). If the crystal is anisotropic, there are additional contributions to the couple, arising from the more complex energy landscape of the lattice itself. These effects can strongly influence the dynamic evolution of dislocation networks, and via their governing role in dislocation multiplication phenomena, control plastic flow in metals. In this paper we develop a model for dislocation self-forces in a general anisotropic crystal, and briefly consider the technologically important example of α-iron, which becomes increasingly anisotropic as the temperature approaches that of the α-γ phase transition at 912 0 C.

  3. Atlantoaxial dislocation with special emphasis on computed tomography findings

    Energy Technology Data Exchange (ETDEWEB)

    Miyasaka, Kazuo; Isu, Toyohiko; Abe, Satoru; Takei, Hidetoshi; Irie, Goro

    1983-01-01

    In this study, the authors evaluated the effectiveness of computed tomography (CT) in the diagnosis of atlantoaxial dislocation (AAD). On the basis of CT evidence of Cl-2 interrelationship, AAD in 26 patients was classified into 4 major types; anteroposterior dislocation in 13 patients, transverse dislocation in 2, anteroposterior-transverse dislocation in 3, and rotatory dislocation in 8. A thick wad of soft tissue on the posterior aspect of the odontoid was found in as many as 38% of the patients and related to compromise the spinal canal. Association of atlantooccipital subluxation with AAD was not rarely encountered in this series (6 out of 26 patients). CT can most optimally and noninvasively demonstrate relationship among the occipitoatlanto-axial complex and associated soft tissue abnormalities. (author).

  4. Implicit and Explicit Cognitive Processes in Incidental Vocabulary Acquisition

    Science.gov (United States)

    Ender, Andrea

    2016-01-01

    Studies on vocabulary acquisition in second language learning have revealed that a large amount of vocabulary is learned without an overt intention, in other words, incidentally. This article investigates the relevance of different lexical processing strategies for vocabulary acquisition when reading a text for comprehension among 24 advanced…

  5. Is Incidental Vocabulary Acquisition Feasible to EFL Learning?

    Science.gov (United States)

    Luo, Jian-ping

    2013-01-01

    For learning English as a foreign language, the efficiency of the approach of incidental vocabulary acquisition depends on the word frequency and text coverage. However, the statistics of English corpus reveals that English is a language that has a large vocabulary size but a low word frequency as well as text coverage, which is obviously not in…

  6. Positron emission tomography of incidentally detected small pulmonary nodules

    DEFF Research Database (Denmark)

    Fischer, B M; Mortensen, J; Dirksen, A

    2004-01-01

    The aim of this study was to assess the value of fluorodeoxyglucose positron emission tomography (FDG PET) imaging of small pulmonary nodules incidentally detected by spiral computed tomography (CT) in a high-risk population. Ten patients (five females, five males, aged 54-72 years) were recruited...

  7. Renal arterial aneurysm--an incidental finding at autopsy.

    Directory of Open Access Journals (Sweden)

    Vaideeswar P

    1998-01-01

    Full Text Available Herein we describe a rare case of saccular renal artery aneurysm seen as an incidental autopsy finding in an elderly, hypertensive female. The aneurysm was seen as a small exophytic mass with calcified wall and lumen occluded by recanalized thrombus.

  8. Incidental finding of hypertension and diminished femoral pulses ...

    African Journals Online (AJOL)

    2012-06-08

    Jun 8, 2012 ... Case Study: Incidental finding of hypertension and diminished femoral pulses. 168. Vol 55 No 2. S Afr Fam Pract 2013. Introduction. Coarctation of the aorta is ... Surgery of the aorta and its branches. Philadelphia: WB Saunders Company, 2000; p. 3-10. 2. Rao PS. Coarctation of the aorta. Curr Cardiol Rep.

  9. Incidental finding of hypertension and diminished femoral pulses ...

    African Journals Online (AJOL)

    Incidental finding of hypertension and diminished femoral pulses: short-segment stenosis of the aorta just distal to the origin of the left subclavian artery. ... Young patients may present within the first few weeks of life with poor feeding, tachypnea and lethargy. They usually progress to overt congestive heart failure and shock.

  10. Fisheries in small reservoirs in Northern Ghana: Incidental Benefit or ...

    African Journals Online (AJOL)

    Fisheries in small reservoirs in the Upper East Region are perceived to be an incidental benefit and the potential of this livelihood strategy is neglected. However, in some communities fishing in small reservoirs is part of their livelihood strategies. Several participatory appraisal tools provided entry points for investigations, ...

  11. Task type and incidental L2 vocabulary learning: Repetition versus ...

    African Journals Online (AJOL)

    This study investigated the effect of task type on incidental L2 vocabulary learning. The different tasks investigated in this study differed in terms of repetition of encounters and task involvement load. In a within-subjects design, 72 Iranian learners of English practised 18 target words in three exercise conditions: three ...

  12. Clinical characteristics and prognosis of incidentally detected lung cancers.

    Science.gov (United States)

    Quadrelli, S; Lyons, G; Colt, H; Chimondeguy, D; Buero, A

    2015-01-01

    To evaluate clinical characteristics and outcomes in incidentally detected lung cancer and in symptomatic lung cancer. We designed a retrospective study including all patients undergoing pulmonary resection with a curative intention for NSCLC. They were classified into two groups according to the presence or absence of cancer-related symptoms at diagnosis in asymptomatic (ASX)—incidental diagnosis—or symptomatic. Of the 593 patients, 320 (53.9%) were ASX. In 71.8% of these, diagnosis was made by chest X-ray. Patients in the ASX group were older (P = 0.007), had a higher prevalence of previous malignancy (P = 0.002), presented as a solitary nodule more frequently (P ASX (P = 0.001). Median survival times in pathological stages IIIB-IV were not significantly different. Incidental finding of NSCLC is not uncommon even among nonsmokers. It occurred frequently in smokers and in those with history of previous malignancy. Mortality of incidental diagnosis group was lower, but the better survival was related to the greater number of patients with earlier-stage disease.

  13. Preliminary Assessment of Cetacean Incidental Mortality in Artisanal ...

    African Journals Online (AJOL)

    Three dolphin species and humpback whales were reported accidentally caught in fishing gear meant to catch sharks. Dolphins were mostly reported as to be entangled in gillnets; conversely longlines were only described to incidentally catch humpback whales. Bottlenose and spinner dolphins were respectively 48.10% ...

  14. Guidance of Spatial Attention by Incidental Learning and Endogenous Cuing

    Science.gov (United States)

    Jiang, Yuhong V.; Swallow, Khena M.; Rosenbaum, Gail M.

    2013-01-01

    Our visual system is highly sensitive to regularities in the environment. Locations that were important in one's previous experience are often prioritized during search, even though observers may not be aware of the learning. In this study we characterized the guidance of spatial attention by incidental learning of a target's spatial probability,…

  15. Incidental right Bochdalek hernia with interruption of the inferior ...

    African Journals Online (AJOL)

    2014-05-30

    May 30, 2014 ... Case Report doi:10.4102/sajr.v18i1.592 http://sajr.org.za. Incidental right Bochdalek hernia with interruption of the inferior vena cava and hepatic venous collateral continuation: A case report. Authors: Farzanah I. Ismail1. Rule Human2. Anith Chacko1. Parmanand Naran2. Samia Ahmad1. Siraj Ellemdin2.

  16. Incidental Learning of Geospatial Concepts across Grade Levels: Map Overlay

    Science.gov (United States)

    Battersby, Sarah E.; Golledge, Reginald G.; Marsh, Meredith J.

    2006-01-01

    In this paper, the authors evaluate map overlay, a concept central to geospatial thinking, to determine how it is naively and technically understood, as well as to identify when it is leaner innately. The evaluation is supported by results from studies at three grade levels to show the progression of incidentally learned geospatial knowledge as…

  17. Texture and flavour memory in foods : an incidental learning experiment

    NARCIS (Netherlands)

    Mojet, J.; Köster, E.P.

    2002-01-01

    Memory plays a major role in the formation of food expectations. How accessible and how accurate is incidentally acquired and stored product information? In the present experiment the memory for variations in texture (and flavour) was tested with a new and ecologically valid method. Subjects (N =

  18. Texture and flavour memory in foods : an incidental learning experiment

    NARCIS (Netherlands)

    Mojet, J.; Koster, E.P.

    2002-01-01

    Memory plays a major role in the formation of food expectations. How accessible and how accurate is incidentally acquired and stored product information? In the present experiment the memory for variations in texture (and flavour) was tested with a new and ecologically valid method. Subjects (N=69:

  19. Dislocation Interactions in Olivine Revealed by HR-EBSD

    Science.gov (United States)

    Wallis, David; Hansen, Lars N.; Britton, T. Ben; Wilkinson, Angus J.

    2017-10-01

    Interactions between dislocations potentially provide a control on strain rates produced by dislocation motion during creep of rocks at high temperatures. However, it has been difficult to establish the dominant types of interactions and their influence on the rheological properties of creeping rocks due to a lack of suitable observational techniques. We apply high-angular resolution electron backscatter diffraction to map geometrically necessary dislocation (GND) density, elastic strain, and residual stress in experimentally deformed single crystals of olivine. Short-range interactions are revealed by cross correlation of GND density maps. Spatial correlations between dislocation types indicate that noncollinear interactions may impede motion of proximal dislocations at temperatures of 1000°C and 1200°C. Long-range interactions are revealed by autocorrelation of GND density maps. These analyses reveal periodic variations in GND density and sign, with characteristic length scales on the order of 1-10 μm. These structures are spatially associated with variations in elastic strain and residual stress on the order of 10-3 and 100 MPa, respectively. Therefore, short-range interactions generate local accumulations of dislocations, leading to heterogeneous internal stress fields that influence dislocation motion over longer length scales. The impacts of these short- and/or long-range interactions on dislocation velocities may therefore influence the strain rate of the bulk material and are an important consideration for future models of dislocation-mediated deformation mechanisms in olivine. Establishing the types and impacts of dislocation interactions that occur across a range of laboratory and natural deformation conditions will help to establish the reliability of extrapolating laboratory-derived flow laws to real Earth conditions.

  20. Ab initio simulation of dislocation cores in metals; Simulation ab initio des coeurs de dislocation dans les metaux

    Energy Technology Data Exchange (ETDEWEB)

    Ventelon, L. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SRMP), 91 - Gif-sur-Yvette (France)

    2008-07-01

    In the framework of the multi scale simulation of metals and alloys plasticity, the aim of this study is to develop a methodology of ab initio dislocations study and to apply it to the [111] screw dislocation in the bc iron. (A.L.B.)

  1. La música incidental en el cine y el teatro

    OpenAIRE

    Olarte Martínez, Matilde María

    2002-01-01

    [ES] Este artículo revisa el papel protagonista de la música incidental en el cine y en el teatro, partiendo de la definición estricta de música incidental y accidental, revisando las principales evoluciones que la música incidental ha experimentado en el cine, y deteniéndose en el género del musical, como un ejemplo significativo de la creación incidental musical actual. [EN] In this article we study the main role of the incidental music for films and theatre plays, starting from the stri...

  2. The Incidental Thyroid Lesion in Parathyroid Disease Management

    Directory of Open Access Journals (Sweden)

    Uthman Alamoudi MD

    2017-03-01

    Full Text Available Objective The incidental thyroid lesion is a common finding during general imaging studies. Their management has been the subject of numerous studies and recommendations. Parathyroid disease workup necessitates imaging investigation of the adjacent thyroid gland and therefore provides a unique window to the perioperative management of thyroid incidentaloma. The specific prevalence of incidental thyroid lesions in the context of parathyroid disease is unknown. We seek to investigate its prevalence during parathyroid workup and surgery and to ascertain if there was a change in management of these patients. Study Design Five-year retrospective database review. Setting Tertiary care medical center. Subjects and Methods The source and indication for referral, preoperative investigation findings, and management of the incidental thyroid lesions were examined. The actual procedure performed and final pathology results were assessed. Results A total of 98 patients and 106 operations, including revision surgeries, were identified. There were 21 incidental thyroid lesions (21.4% detected, whereby 15 patients underwent fine-needle aspirations and 12 subsequently had diagnostic hemithyroidectomies. This decision was made preoperatively in 5 patients and intraoperatively in 7 patients at the time of parathyroid surgery. Along with other pathologies, there were 7 patients with micropapillary thyroid carcinoma identified. Conclusions In our series, the prevalence of incidental thyroid lesion and thyroid malignancy is comparable to the general population. The management of the initial parathyroid disease in our patients was altered by the imaging and cytological findings of these thyroid lesions. This has implications on perioperative counseling of the thyroid and parathyroid disease.

  3. Incidental findings in chest X-rays; Zufallsbefunde im Roentgenthorax

    Energy Technology Data Exchange (ETDEWEB)

    Wielpuetz, M.O.; Kauczor, H.U. [Universitaetsklinikum Heidelberg, Klinik fuer Diagnostische und Interventionelle Radiologie, Heidelberg (Germany); Universitaet Heidelberg, Translational Lung Research Center (TLRC), Deutsches Zentrum fuer Lungenforschung (DZL), Heidelberg (Germany); Universitaetsklinikum Heidelberg, Klinik fuer Diagnostische und Interventionelle Radiologie mit Nuklearmedizin, Thoraxklinik, Heidelberg (Germany); Weckbach, S. [Universitaetsklinikum Heidelberg, Klinik fuer Diagnostische und Interventionelle Radiologie, Heidelberg (Germany); Universitaet Heidelberg, Translational Lung Research Center (TLRC), Deutsches Zentrum fuer Lungenforschung (DZL), Heidelberg (Germany)

    2017-04-15

    Conventional projection radiography (chest x-ray) is one of the most frequently requested procedures in radiology. Even though chest x-ray imaging is frequently performed in asymptomatic patients for preoperative assessment, clinically relevant incidental findings are relatively scarce. This is due to the relatively low sensitivity of chest x-rays where few clinically relevant incidental findings are to be expected, as any detectable pathologies will as a rule already be clinically symptomatic. Recommendations from relevant societies for the management of incidental findings, apart from the clarification of incidental nodules, do not exist. This review article therefore describes the most frequent and typical incidental findings of lung parenchyma (apart from pulmonary nodules), mediastinal structures including the hilum of the lungs, pleura, chest wall and major vessels. Also described are those findings which can be diagnosed with sufficient certainty from chest x-rays so that further clarification is not necessary and those which must be further clarified by multislice imaging procedures or other techniques. (orig.) [German] Eine der haeufigsten Untersuchungen in der Radiologie ist die konventionelle Projektionsradiographie des Thorax (Roentgenthorax). Auch wenn projektionsradiographische Aufnahmen im Rahmen einer praeoperativen Abklaerung haeufig als orientierende Untersuchung angefertigt werden, sind - bedingt durch die relativ geringe Sensitivitaet des Roentgenthorax - wenig klinisch relevante Zufallsbefunde zu erwarten, da nachweisbare Pathologien in der Regel bereits auch klinisch apparent sind. Empfehlungen entsprechender Fachgesellschaften zu Zufallsbefunden im Roentgenthorax jenseits der Abklaerung von Rundherden liegen nicht vor. Die vorliegende Arbeit beleuchtet daher haeufige und typische Zufallsbefunde des Lungenparenchyms (ausser den Lungenrundherden), der mediastinalen Strukturen einschliesslich der Hili, der Pleura, der Thoraxwand sowie der

  4. To search or to like: Mapping fixations to differentiate two forms of incidental scene memory.

    Science.gov (United States)

    Choe, Kyoung Whan; Kardan, Omid; Kotabe, Hiroki P; Henderson, John M; Berman, Marc G

    2017-10-01

    We employed eye-tracking to investigate how performing different tasks on scenes (e.g., intentionally memorizing them, searching for an object, evaluating aesthetic preference) can affect eye movements during encoding and subsequent scene memory. We found that scene memorability decreased after visual search (one incidental encoding task) compared to intentional memorization, and that preference evaluation (another incidental encoding task) produced better memory, similar to the incidental memory boost previously observed for words and faces. By analyzing fixation maps, we found that although fixation map similarity could explain how eye movements during visual search impairs incidental scene memory, it could not explain the incidental memory boost from aesthetic preference evaluation, implying that implicit mechanisms were at play. We conclude that not all incidental encoding tasks should be taken to be similar, as different mechanisms (e.g., explicit or implicit) lead to memory enhancements or decrements for different incidental encoding tasks.

  5. Concept of healing of recurrent shoulder dislocation

    Directory of Open Access Journals (Sweden)

    Donato D'Angelo

    2014-08-01

    Full Text Available This paper presents the main surgical techniques applied in the treatment of anterior recurrent shoulder dislocation, aiming the achievement of the normality of articulate movements. This was obtained by combining distinct surgical procedures, which allowed the recovery of a complete functional capacity of the shoulder, without jeopardizing the normality of movement, something that has not been recorded in the case of the tense sutures of the surgical procedures of Putti-Platt, Bankart, Latarjet, Dickson-O'Dell and others.The careful review of the methods applied supports the conclusion that recurrent shoulder dislocation can be cured, since cure has been obtained in 97% of the treated cases. However, some degree of limitation in the shoulder movement has been observed in most of the treated cases.Our main goal was to achieve a complete shoulder functional recovery, by treating simultaneously all of the anatomical–pathological lesions, without considering the so-called essential lesions.The period of post-operatory immobilization only last for the healing of soft parts; this takes place in a position of neutral shoulder rotation, since the use of vascular bone graft eliminates the need for long time immobilization, due to the shoulder stabilization provided by rigid fixation of the coracoid at the glenoid edge, as in the Latarjet's technique.Our procedure, used since 1959, comprises the association of several techniques, which has permitted shoulder healing without movement limitation. That was because of the tension reduction in the sutures of the subescapularis, capsule, and coracobraquialis muscles.

  6. Lens dislocation has a possible relationship with laser iridotomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-12-01

    Full Text Available Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation.Keywords: lens dislocation, laser iridotomy, primary angle closure glaucoma

  7. Dislocation following total knee arthroplasty: A report of six cases

    Directory of Open Access Journals (Sweden)

    Villanueva Manuel

    2010-01-01

    Full Text Available Background: Dislocation following total knee arthroplasty (TKA is the worst form of instability. The incidence is from 0.15 to 0.5%. We report six cases of TKA dislocation and analyze the patterns of dislocation and the factors related to each of them. Materials and Methods: Six patients with dislocation of knee following TKA are reported. The causes for the dislocations were an imbalance of the flexion gap (n=4, an inadequate selection of implants (n=1, malrotation of components (n=1 leading to incompetence of the extensor mechanism, or rupture of the medial collateral ligament (MCC. The patients presented complained of pain, giving way episodes, joint effusion and difficulty in climbing stairs. Five patients suffered posterior dislocation while one anterior dislocation. An urgent closed reduction of dislocation was performed under general anaesthesia in all patients. All patients were operated for residual instability by revision arthroplasty after a period of conservative treatment. Results: One patient had deep infection and knee was arthrodesed. Two patients have a minimal residual lag for active extension, including a patient with a previous patellectomy. Result was considered excellent or good in four cases and fair in one, without residual instability. Five out of six patients in our series had a cruciate retaining (CR TKA designs: four were revised to a posterior stabilized (PS TKA and one to a rotating hinge design because of the presence of a ruptured MCL. Conclusion: Further episodes of dislocation or instability will be prevented by identifying and treating major causes of instability. The increase in the level of constraint and correction of previous technical mistakes is mandatory.

  8. Choice of scalar measure for crystal curvature to image dislocation substructure in terms of discrete orientation data

    Science.gov (United States)

    Zisman, Alexander

    2016-04-01

    Starting from Nye's tensor, alternative characteristics of crystal curvature indicative of dislocation content are considered subject to very low thickness of investigated matter under the free surface and discreteness of orientation sampling. Analysis within the framework of continuum mechanics, undertaken to allow for such conditions peculiar to the electron backscatter diffraction (EBSD) technique, has shown the variable part of orientations expressed in a vector form to be most sensitive to lattice defects when projected to the free surface plane. Hence, as verified with EBSD data on a grain junction in a low deformed IF steel, magnitude of the projected field allows one to map plastic strains inhomogeneous within grains whereas divergence of this field distinctly images and quantifies low-angle dislocation boundaries formed at low strains.

  9. Thermally activated dislocation creep model for primary water stress corrosion cracking of NiCrFe Alloys

    International Nuclear Information System (INIS)

    Hall, M.M. Jr.

    1995-01-01

    There is a growing awareness that environmentally assisted creep plays an important role in intergranular stress corrosion cracking (IGSCC) of NiCrFe alloys in the primary coolant water environment of a pressurized water reactor (PWR). The expected creep mechanism is the thermally activated glide of dislocations. This mode of deformation is favored by the relatively low temperature of PWR operation combined with the large residual stresses that are most often identified as responsible for the SCC failure of plant components. Stress corrosion crack growth rate (CGR) equations that properly reflect the influence of this mechanism of crack tip deformation are required for accurate component life predictions. A phenomenological IGSCC-CGR model, which is based on an apriori assumption that the IGSCC-CGR is controlled by allow temperature dislocation creep mechanism, is developed in this report. Obstacles to dislocation creep include solute atoms such as carbon, which increase the lattice friction force, and forest dislocations, which can be introduced by cold prestrain. Dislocation creep also may be environmentally assisted due to hydrogen absorption at the crack tip. The IGSCC-CGR model developed here is based on an assumption that crack growth occurs by repeated fracture events occurring within an advancing crack-tip creep-fracture zone. Thermal activation parameters for stress corrosion cracking are obtained by fitting the CGR model to IGSCC-CGR data obtained on NiCrFe alloys, Alloy X-750 and Alloy 600. These IGSCC-CGR activation parameters are compared to activation parameters obtained from creep and stress relaxation tests. Recently reported CGR data, which exhibit an activation energy that depends on yield stress and the applied stress intensity factor, are used to benchmark the model. Finally, the effects of matrix carbon concentration, grain boundary carbides and absorbed hydrogen concentration are discussed within context of the model. (author). 19 refs, 7 figs

  10. Epidemiology of Elbow Dislocations in High School Athletes.

    Science.gov (United States)

    Dizdarevic, Ismar; Low, Sara; Currie, Dustin W; Comstock, R Dawn; Hammoud, Sommer; Atanda, Alfred

    2016-01-01

    The elbow is the second most commonly dislocated major joint in the general population. Previous studies that focused on emergency department populations indicate that such injuries occur most frequently among adolescent athletes. To describe the epidemiological rates and patterns of sports-related elbow dislocations in high school athletes. Descriptive epidemiology study. Sports-related injury data for the 2005-2006 through 2013-2014 academic years from a national convenience sample of high schools participating in the National High School Sports-Related Injury Surveillance Study (High School Reporting Information Online [RIO]) were analyzed. Certified athletic trainers participating in High School RIO reported 115 of 1246 (9.2%) elbow injuries as elbow dislocations. A total of 30,415,179 athlete exposures (AEs) were reported during the study period, resulting in a dislocation rate of 0.38 per 100,000 AEs. The majority of the dislocations resulted from boys' wrestling (46.1%) and football (37.4%). Elbow dislocation rates were higher in competition than in practice. Also, 91.3% of dislocations occurred in boys' sports. Among both boys (60.4%) and girls (88.9%), the majority of injuries occurred during varsity sports activities. Contact with another person was the most common injury mechanism (46.9%), followed by contact with the playing surface (46.0%). Dislocations more commonly resulted in removal from play for more than 3 weeks (23.4% vs 6.9%, respectively) or medical disqualification (36.9% vs 7.0%, respectively) compared with other elbow injuries. Dislocations were also more likely to result in surgical treatment than other elbow injuries (13.6% vs 4.7%, respectively). In high school athletes, elbow dislocations result in longer removal from play and are more likely to require surgical treatment than nondislocation-associated elbow injuries. Rates and patterns of elbow dislocations vary by sport. In high-risk sports, focused sport-specific prevention

  11. Constrained liners for recurrent dislocations in total hip arthroplasty

    DEFF Research Database (Denmark)

    Knudsen, R; Ovesen, O; Kjaersgaard-Andersen, P

    2009-01-01

    This study reports the results and complications from treating recurrent hip dislocations with a constrained liner (CL) after total hip arthroplasty (THA). Forty patients who had a CL inserted as a secondary prophylactic treatment were retrospectively reviewed after a median observation period...... of 27 months (range 7-77 months). During the observation period five patients had to be revised: one for deep infection and four on account of re-dislocations. Our results indicate that patients with recurrent THA dislocations can be treated with a CL and has a satisfactory low complication rate...

  12. Galeazzi fracture with volar dislocation of the distal radioulnar joint.

    Science.gov (United States)

    Kim, Suezie; Ward, James P; Rettig, Michael E

    2012-11-01

    Galeazzi fracture dislocations are fractures of the distal one-third of the radial diaphysis with traumatic disruption of the distal radioulnar joint (DRUJ). This injury results in subluxation or dislocation of the ulnar head. We present a case of a Galeazzi fracture with a volar dislocation of the DRUJ. Open reduction of the DRUJ with Kirschner wire fixation in pronation was necessary to reduce the joint and maintain anatomic alignment. Repair of the triangular fibrocartilage complex was also necessary to maintain stability of the DRUJ.

  13. Bilateral Posterior Native Hip Dislocations after Fall from Standing

    Directory of Open Access Journals (Sweden)

    Jane Xiao

    2017-10-01

    Full Text Available We present a case of bilateral posterior native hip dislocations after a fall from standing. This exceedingly rare diagnosis is classically associated with younger patients whose bones are strong enough to dislocate rather than fracture in the setting of a high-momentum collision. We present an unusual case of an 88-year-old male with native hips who sustained a low-energy collision after falling from standing and was found to have bilateral posterior hip dislocations without associated pelvis or femur fractures.

  14. Radiological difficulty in identifying unicompartmental knee replacement dislocation

    Directory of Open Access Journals (Sweden)

    Mr Oruaro Adebayo Onibere, MBBS, MRCS

    2017-09-01

    Full Text Available Unicondylar knee replacement is a relatively common elective orthopedic procedure but is not often seen in the Emergency Department setting. Familiarity with normal clinical and radiological appearances is difficult to gain. Dislocation of the mobile bearing component “spacer” is a known complication of unicondylar knee replacements, and these patients will initially present to the accident and Emergency Department. In this setting, an accurate and prompt diagnosis is necessary to appropriately manage the patient's condition. There is normally a radiological challenge in identifying dislocated mobile bearings on plain radiographs. These patients may need to have further imaging, such as a computer tomographic scan to identify the dislocated mobile bearing.

  15. Superior dislocation of the patella: a case report

    Directory of Open Access Journals (Sweden)

    Garcia-Balletbo Montserrat

    2009-07-01

    Full Text Available Abstract Background Superior dislocation of the patella is an uncommon condition that mainly occurs in knees with a high patella and medial femorotibial degenerative arthritis. There are no previous reports of this condition occurring in association with tibial valgus osteotomy. Case report: We report the case of a patient in whom vertical dislocation recurred twice at 4 months after tibial valgus osteotomy. To avert additional recurrence or new dislocations, the patient was treated surgically to remove the existing osteophytes. Conclusions: An arthroscopic approach was decided because of the lower associated morbidity and good results with this technique compared to open surgery.

  16. Concentric reduction of the dislocated hip: computed tomographic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, R.J.

    1984-01-01

    Concentric reduction of a dislocated hip can be evaluated by anteroposterior views or linear tomography. Anterior relationships, however, may be difficult to evaluate from a frontal radiograph despite good visibility. Computed tomography (CT), because of its cross-sectional imaging capabilities, is superior in demonstrating these relationships. The CT appearance of two types of dislocations (posterior and lateral ) is described. A posterior dislocation should be suspected if the femoral metaphysis approximates the acetabulum, a mass projects behind the ischium, or the fat plane anterior to the gluteus maximus is deformed or displaced posteriorly.

  17. Dislocations in extruded Co-49.3 at. pct Al

    Science.gov (United States)

    Yaney, D. L.; Nix, W. D.; Pelton, A. R.

    1986-01-01

    Polycrystalline Co-49.3 at. pct Al, which had been extruded at 1505 K, was examined using transmission electron microscopy. Diffraction contrast analysis showed that b = 100 as well as b = 111 line dislocations contribute to elevated temperature deformation in CoAl. Therefore, it was concluded that sufficient slip systems exist in CoAl to allow for general plasticity in the absence of diffusional mechanisms. Line dislocations of the type b = 001 were observed on both 110 and 100 planes while b = 111 line dislocations were observed on 1 -1 0 planes.

  18. Atomic-resolution study of dislocation structures and interfaces in poly-crystalline thin film CdTe using aberration-corrected STEM

    Science.gov (United States)

    Paulauskas, Tadas; Colegrove, Eric; Buurma, Chris; Kim, Moon; Klie, Robert

    2014-03-01

    Commercial success of CdTe-based thin film photovoltaic devices stems from its nearly ideal direct band gap which very effectively couples to Sun's light spectrum as well as ease of manufacturing and low cost of these modules. However, to further improve the conversion efficiency beyond 20 percent, it is important to minimize the harmful effects of grain boundaries and lattice defects in CdTe. Direct atomic-scale characterization is needed in order identify the carrier recombination centers. Likewise, it is necessary to confirm that passivants in CdTe, such as Cl, are able to diffuse and bind to the target defects. In this study, we characterize dislocation structures and grain boundaries in poly-crystalline CdTe using aberration-corrected cold-field emission scanning transmission electron microscopy (STEM). The chemical composition of Shockley partial, Frank and Lomer-Cottrell dislocations is examined via atomic column-resolved X-ray energy dispersive (XEDS) and electron energy-loss spectroscopies (EELS). Segregation of Cl towards dislocation cores and grain boundaries is shown in CdCl2 treated samples. We also investigate interfaces in ultra-high-vacuum bonded CdTe bi-crystals with pre-defined misorientation angles which are intended to mimic grain boundaries. Funded by: DOE EERE Sunshot Award EE0005956.

  19. Effects of γ' Precipitation, Dislocation Density, and Grain Size on Stress-Relaxation Properties of INCONEL X-750 Helical Springs

    Science.gov (United States)

    Ha, Jeong Won; Seong, Baek Seok; Woo, Wanchuck; Jeong, Hi Won; Choi, Yoon Suk; Kang, Namhyun

    2017-08-01

    INCONEL X-750 specimens were manufactured into helical springs by drawing and coiling followed by aging. They were subsequently subjected to stress-relaxation tests. Stress relaxation is the important property of springs that are compressed at elevated temperatures. To understand stress relaxation, this study investigated the effect of the drawing ratio (DR) on the γ' size and volume fraction, grain size, carbide volume fraction, and dislocation density. Small-angle neutron scattering was used to measure the size and volume fraction of γ' phase, and X-ray diffraction was employed to analyze the dislocation density in the springs as a function of the DR. The smallest DR specimen (DR0) had a longer free length than the larger DR specimens (DR17 and DR42) after the stress-relaxation test was completed at 773 K (500 °C) for 300 hours. However, the size and volume fraction of γ', along with the dislocation density, had no influence on the stress relaxation of the INCONEL X-750 springs. The decreased grain size ( d) due to an increase in the DR was the main factor in the increase in the stress relaxation of the springs. The decrease in grain size displayed a nonlinear relationship with the increase in stress relaxation. The stress-relaxation behavior relationship was d -3. Grain boundaries were determined to play a role in dislocation sink via transmission electron microscopy (TEM) observations. Grain boundary diffusion accommodated by slip was responsible for the stress-relaxation properties of the spring at an elevated temperature (773 K = 500 °C).

  20. 76 FR 16311 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2011-03-23

    ... passes into the sea across the air-water boundary. Submerged animals would have to be directly underneath... Steller sea lion haulout spit, which was unoccupied each time the incursions occurred. Description of.... Aerial survey data indicate that Steller sea lions, harbor seals, gray whales (Eschrichtius robustus...

  1. Dislocation nucleation and vacancy formation during high-speed deformation of fcc metals

    DEFF Research Database (Denmark)

    Schiøtz, J.; Leffers, T.; Singh, B.N.

    2001-01-01

    . The dislocations are nucleated as single Shockley partials. The large stresses required before dislocations are nucleated result in a very high dislocation density, and therefore in many inelastic interactions between the dislocations. These interactions create vacancies and a very large vacancy concentration...

  2. Accurate electron channeling contrast analysis of a low angle sub-grain boundary

    International Nuclear Information System (INIS)

    Mansour, H.; Crimp, M.A.; Gey, N.; Maloufi, N.

    2015-01-01

    High resolution selected area channeling pattern (HR-SACP) assisted accurate electron channeling contrast imaging (A-ECCI) was used to unambiguously characterize the structure of a low angle grain boundary in an interstitial-free-steel. The boundary dislocations were characterized using TEM-style contrast analysis. The boundary was determined to be tilt in nature with a misorientation angle of 0.13° consistent with the HR-SACP measurements. The results were verified using high accuracy electron backscatter diffraction (EBSD), confirming the approach as a discriminating tool for assessing low angle boundaries

  3. In situ TEM study on elastic interaction between a prismatic loop and a gliding dislocation

    International Nuclear Information System (INIS)

    Matsukawa, Yoshitaka; Liu, Grace S.

    2012-01-01

    In situ straining in a transmission electron microscope was performed in order to investigate dislocation interactions with a prismatic loop, which as a mobile obstacle is expected to be displaced by the strain-field of dislocation prior to physical contact. It was found that when a gliding dislocation approached a critical distance, the prismatic loop was certainly attracted to the dislocation. The captured loop disrupted the dislocation motion and was not dragged along with the mobile dislocation. Instead, the dislocation bypassed the loop via cross-slip to another slip plane with a resolved shear stress estimated to be 40% lower than that of the original plane.

  4. Successful Thrombolysis despite Having an Incidental Unruptured Cerebral Aneurysm

    Directory of Open Access Journals (Sweden)

    Diana Briosa e Gala

    2014-01-01

    Full Text Available Purpose. To report a case of successful thrombolysis performed in a patient with an incidental unruptured intracranial aneurysm and review the literature. Case Report. Patient admitted for ischemic stroke due to left posterior cerebral artery occlusion, with an incidental right middle cerebral artery aneurysm, who underwent treatment with tissue plasminogen activator (rtPA resulting in clinical improvement without complications. Conclusion. The presence of unruptured intracranial aneurysms is considered as a contraindication to thrombolysis, due to a potentially higher hemorrhagic risk of aneurysm rupture. Patients, otherwise, eligible for thrombolysis are usually excluded from receiving this emergent treatment, despite its potential benefits. A reevaluation of the strict exclusion criteria for thrombolysis in acute stroke patients should be considered.

  5. Incidental findings, genetic screening and the challenge of personalisation

    Directory of Open Access Journals (Sweden)

    Carlo Petrini

    2014-12-01

    Full Text Available Genetic tests frequently produce more information than is initially expected. Several documents have addressed this issue and offer suggestions regarding how this information should be managed and, in particular, concerning the expedience of revealing (or not revealing it to the persons concerned. While the approaches to the management of these incidental findings (IFs vary, it is usually recommended that the information be disclosed if there is confirmed clinical utility and the possibility of treatment or prevention. However, this leaves unsolved some fundamental issues such as the different ways of interpreting "clinical utility", countless sources of uncertainty and varying ways of defining the notion of "incidental". Guidelines and other reference documents can offer indications to those responsible for managing IFs but should not be allowed to relieve researchers and healthcare professionals of their responsibilities.

  6. The prevalence of incidentally detected adrenal enlargement on CT

    International Nuclear Information System (INIS)

    Tang, Y.Z.; Bharwani, N.; Micco, M.; Akker, S.; Rockall, A.G.; Sahdev, A.

    2014-01-01

    Aim: To assess the prevalence and the department's detection rate of adrenocortical hyperplasia. Materials and methods: All computed tomography (CT) examinations of the adrenal glands between February and April 2011 were reviewed. The study excluded patients with known underlying cancer, abdominal trauma, or endocrine disease. The adrenal gland was deemed enlarged if its body was greater than 10 mm diameter, or a limb greater than 5 mm. Results: There were a total of 564 eligible CT studies during this period. A total of 64 cases of incidental adrenal enlargement were found giving a prevalence of 11.3%. Only nine cases were reported in the contemporaneous CT report. Conclusion: The results of the present study show that incidental adrenal enlargement has a significant prevalence. It is often dismissed during reporting, and awareness needs to be raised in the radiological community. Equally, the clinical and biochemical significance needs to be assessed with endocrine correlation

  7. Irradiation deformation due to SIPA induced dislocation anisotropy

    International Nuclear Information System (INIS)

    Woo, CH.

    1980-02-01

    A contribution to irradiation deformation resulting from the stress-induced preferred adsorption (SIPA) effect is considered. SIPA causes a variation of the growth rates of irradiation-generated dislocation loops, according to the alignment of their Burgers vectors with respect to the applied stress. A prolinged period under an applied stress then creates an anisotropic dislocation structure in which the majority of dislocations have their Burgers vectors in alignment with the stress. In the presence of 'neutral' sinks, the resulting anisotropic dislocation structure causes plastic deformation similar to the way in which irradiation growth occurs in zirconium. This mechanism is called SIPA-induced growth (SIG). We have shown that SIG is very significant in comparison to SIPA, except when little or no loop growth has occurred during the period the stress is applied. This report contains the detailed formulation and derivation of the formulae for the evaluation of the contribution due to SIG. (auth)

  8. [Posterior radiocarpal fracture-dislocation (eight case reports)].

    Science.gov (United States)

    Lahtaoui, A; el Bardouni, A; Ismael, F; Jellali, T; Bahri, A; el Yaacoubi, M; el Manouar, M

    2002-07-01

    The Authors report a retrospective series of eight cases of posterior radiocarpal fracture-dislocation. Average age of patients was 32 years (23/54), with a male predominance (7 men and a woman). Injury was often due to a fall on the hand in extension from an elevated place (5/8). The wrist in back of fork is the characteristic deformity. Diagnosis was confirmed by AP and lateral views of the wrist. Radial styloïd fracture, posterior dislocation of the carpus and posterior rim avulsion were constant. Ulnar styloïd fracture was present in half of the cases and distal radio-ulnar dislocation in two cases. Four patients were treated conservatively and four surgically. Whatever the treatment choice, results are satisfactory at a short follow-up. The two patients presenting a distal radio-ulnar dislocation resulted in a bad result.

  9. Anterior Hip Dislocation in a Football Player: A Case Report

    Directory of Open Access Journals (Sweden)

    Alexander Schuh

    2009-01-01

    Full Text Available Hip dislocations during sporting activities represent only 2%–5% of all hip dislocations. Most hip dislocations in sports can be categorised as “less complicated traumatic hip dislocations” by the Stewart-Milford classification due to the fact that minimal force is involved. The incidence of avascular necrosis of the femoral head greatly increases if the time to reduction is more than six hours. We report the case of a 38-year-old football player who suffered hip dislocation while kicking the ball with the medial aspect of the right foot in an external rotated manner of the right hip. Closed reduction was performed within 2 hours; postoperative follow-up was uneventful. Six months later the patient is out of any complaints; there is no sign of AVN of the femoral head.

  10. Infantile and congenital hip dislocation: Assessment by MR imaging

    International Nuclear Information System (INIS)

    Johnson, N.D.; Wood, B.P.; Jackman, K.V.

    1986-01-01

    Dislocations of the infant hip, particularly those that responded poorly to standard treatment, were imaged using a 1.5-T MR imaging unit. Excellent detail of the cartilaginous structures of the femoral head, acetabulum, labrum, pulvinar, and capsular abnormalities was achieved. The most detailed images were obtained using a 3-inch surface coil. The shape and orientation of the acetabulum and femoral head cannot otherwise be as well evaluated, nor can their relationship be as clearly established. Technical factors and considerations of imaging with a 1.5-T magnet, the anatomy of the normal and dislocated hip, and observed variations in acetabular shape and orientation are discussed. MR imaging reliably demonstrates dislocation, and the prolonged T2 of synovial fluid produced an ''arthrogram'' effect, which is useful in the treatment of complicated hip dislocation

  11. Dislocation Characteristics in Lath Martensitic Steel by Neutron Diffraction

    Science.gov (United States)

    Harjo, S.; Kawasaki, T.; Gong, W.; Aizawa, K.

    2016-09-01

    In situ neutron diffraction during tensile deformation of an as-quenched lath martensitic 22SiMn2TiB steel, was performed using a high resolution and high intensity time- of-flight neutron diffractometer. The characterizations of dislocations were analyzed using the classical Williamson-Hall (cWH) and modified Williamson-Hall (mWH) plots on the breadth method, and the convolutional multiple whole profile (CMWP) fitting method. As results, the dislocation density as high as 1015 m-2 in the as-quenched martensitic steel was determined. The dislocation density was found to decrease qualitatively with plastic deformation by the cWH and mWH plots, but hardly to change by the CMWP method. The scanning transmission electron microscopy observation supported the results of the latter method. In the CMWP method, the parameter M that represents the arrangement of dislocations was found to decrease rapidly where a very high work hardening was observed.

  12. Surgical hip dislocation for treatment of cam femoroacetabular impingement

    Directory of Open Access Journals (Sweden)

    Milind M Chaudhary

    2015-01-01

    Conclusion: Cam femoroacetabular Impingement causing pain and limitation of hip movements was treated by open osteochondroplasty after surgical hip dislocation. This reduced pain, improved hip motion and gave good to excellent results in the short term.

  13. Open Anterior Dislocation of the Hip in Togo

    Science.gov (United States)

    Anani, Abalo; Yannick, Dellanh; Gamal, Ayouba; Assang, Dossim

    2016-01-01

    Anterior traumatic dislocations of the hip are much less common than posterior dislocations. To date, 14 cases of open anterior dislocation of the hip associated with such injuries, acetabular and femoral head fractures and femoral vascular and nerve damage have been reported. We present a case of a 23-year-old male who sustained open anterior dislocation of the hip with ipsilateral fracture of the greater trochanter after an accident on the public highway. Additional lesions included an iliac wing fracture and a perineal wound. We report this case because of the rarity and seriousness of this injury due to its progressive complications and difficulties related to its management, which are typical to a developing country like ours. PMID:27247749

  14. Effect of oxygen on dislocation multiplication in silicon crystals

    Science.gov (United States)

    Fukushima, Wataru; Harada, Hirofumi; Miyamura, Yoshiji; Imai, Masato; Nakano, Satoshi; Kakimoto, Koichi

    2018-03-01

    This paper aims to clarify the effect of oxygen on dislocation multiplication in silicon single crystals grown by the Czochralski and floating zone methods using numerical analysis. The analysis is based on the Alexander-Haasen-Sumino model and involves oxygen diffusion from the bulk to the dislocation cores during the annealing process in a furnace. The results show that after the annealing process, the dislocation density in silicon single crystals decreases as a function of oxygen concentration. This decrease can be explained by considering the unlocking stress caused by interstitial oxygen atoms. When the oxygen concentration is 7.5 × 1017 cm-3, the total stress is about 2 MPa and the unlocking stress is less than 1 MPa. As the oxygen concentration increases, the unlocking stress also increases; however, the dislocation velocity decreases.

  15. Nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability.

    Science.gov (United States)

    Wu, Tian-Long; Jia, Jing-Yu; Chen, Wei-Cai; He, Ding-Wen; Cheng, Xi-Gao

    2015-05-01

    Nontraumatic posterior atlantooccipital dislocation has only been rarely reported. In the current study, the authors reported an extremely rare case of nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability. A 47-year-old female was referred with a history of neck pain for 5 years. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. Posterior atlantooccipital dislocation with atlantoaxial instability was confirmed through conventional radiography, computed tomography and magnetic resonance imaging. We performed realignment of the dislocation and posterior occipitocervical (C0-C2) fusion. After the surgery, the patient's symptoms improved significantly and she manifested neurological improvement. To our knowledge, this lesion has not been reported previously. Anomalies of upper cervical spine may have induced this instability.

  16. Retropharyngeal pseudomeningocele presenting as dysphagia after atlantooccipital dislocation.

    Science.gov (United States)

    Cognetti, David M; Enochs, W Scott; Willcox, Thomas O

    2006-09-01

    At the conclusion of this paper, the readers should be able to recognize a retropharyngeal pseudomeningocele as a potential complication of atlanto occipital dislocation. To demonstrate how a retropharyngeal pseudomeningocele may present as dysphagia in a patient who is recovering from atlanto occipital dislocation as well as to discuss the treatment options in this situation. Case report and literature review. Analysis of a case through medical record and literature review. A retropharyngeal pseudomeningocele is a very rare complication of atlanto occipital dislocation. It may develop weeks after the initial injury and can present with respiratory or swallowing difficulties. Decompression via a ventriculoperitoneal or lumboperitoneal shunt facilitates resolution of the cerebral spinal fluid collection. A retropharyngeal pseudomeningocele should be considered in all patients status post-atlanto occipital dislocation who are experiencing respiratory distress or dysphagia.

  17. Simple elbow dislocations: a systematic review of the literature

    NARCIS (Netherlands)

    J. de Haan (Jeroen); N.W.L. Schep (Niels); P. Patka (Peter); D. den Hartog (Dennis)

    2010-01-01

    textabstractObjective: To identify if functional treatment is the best available treatment for simple elbow dislocations. Search strategy: Electronic databases MEDLINE, EMBASE, LILACS, and the Cochrane Central Register of Controlled Trials. Selection criteria: Studies were eligible for inclusion if

  18. Risk of appendicitis in patients with incidentally discovered appendicoliths.

    Science.gov (United States)

    Khan, Muhammad Sohaib; Chaudhry, Mustafa Belal Hafeez; Shahzad, Noman; Tariq, Marvi; Memon, Wasim Ahmed; Alvi, Abdul Rehman

    2018-01-01

    An appendicolith-related appendiceal obstruction leading to appendicitis is a commonly encountered surgical emergency that has clear evidence-based management plans. However, there is no consensus on management of asymptomatic patients when appendicoliths are found incidentally. The objective of this study was to determine the risk of appendicitis in patients with an incidental finding of the appendicolith. A retrospective matched cohort study of patients with appendicolith discovered incidentally on computed tomographic scan from January 2008 to December 2014 at our institution was completed. The size and position of the appendicolith were ascertained. The study group was matched by age and gender to a control group. Both groups were contacted and interviewed regarding development of appendicitis. In total, 111 patients with appendicolith were successfully contacted and included in the study. Mean age was found to be 38 ± 15 y with 36 (32%) of the study population being females. Mean length of appendix was 66 ± 16 mm, and mean width was 5.8 ± 0.9 mm. Mean size of the appendicolith was 3.6 ± 1.1 mm (1.4-7.8 mm). Fifty-eight percent of appendicoliths was located at the proximal end or whole of appendix, 31% at mid area, and 11% at the distal end of appendix. All patients of the study and control groups were contacted, and at a mean follow-up of 4.0 ± 1.7 y, there was no occurrence of acute appendicitis in either group. Patients with incidentally discovered appendicolith on radiological imaging did not develop appendicitis. Hence, the risk of developing acute appendicitis for these patients does not seem higher than the general population. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Incidental Detection of Arteria Lusoria During Transradial Coronary Intervention.

    Science.gov (United States)

    Moorthy, Nagaraja; Setty, Natraj; Kharge, Jayashree; Raghu, Thagachagere R; Nanjappa, Manjunath C

    2017-08-01

    Transradial access has become popular and preferred approach in coronary interventions due to high success rate, low risk of complications and patients' comfort. However various anatomical variations and anomalies may pose technical challenge. Arteria lusoria is an uncommon condition which is technically challenging and may warrant cross-over to alternate access. We report a middle aged male presenting with acute coronary syndrome in which arteria lusoria was incidentally detected during right transradial coronary intervention.

  20. Accessory hepatic lobe in right lumbar region - an incidental finding.

    Science.gov (United States)

    Shrestha, M K; Ghartimagar, D; Ghosh, A

    2014-01-01

    An accessory lobe of liver is a rare congenital anomaly which can be detected incidentally or can even present as acute surgical emergency due to torsion. We report a case of accessory hepatic lobe in right lumbar region in a 21years old female who came for a ultrasound abdomen for lower abdominal pain. We report the importance of ultrasonography and Computed Tomogram (CT) scan for the diagnosis of accessory hepatic lobe.

  1. Small Renal Masses: Incidental Diagnosis, Clinical Symptoms, and Prognostic Factors

    OpenAIRE

    Sánchez-Martín, F. M.; Millán-Rodríguez, F.; Urdaneta-Pignalosa, G.; Rubio-Briones, J.; Villavicencio-Mavrich, H.

    2009-01-01

    Introduction. The small renal masses (SRMs) have increased over the past two decades due to more liberal use of imaging techniques. SRMs have allowed discussions regarding their prognostic, diagnosis, and therapeutic approach. Materials and methods. Clinical presentation, incidental diagnosis, and prognosis factors of SRMs are discussed in this review. Results. SRMs are defined as lesions less than 4 cm in diameter. SRM could be benign, and most malignant SMRs are low stage and low grade. Cli...

  2. PROMOTING INCIDENTAL VOCABULARY LEARNING THROUGH VERBAL DRAMATIZATION OF WORDS

    Directory of Open Access Journals (Sweden)

    Looi-Chin Ch’ng

    2014-12-01

    Full Text Available Despite the fact that explicit teaching of vocabulary is often practised in English as a Second Language (ESL classrooms, it has been proven to be rather ineffective, largely because words are not taught in context. This has prompted the increasing use of incidental vocabulary learning approach, which emphasises on repeated readings as a source for vocabulary learning. By adopting this approach, this study aims to investigate students’ ability in learning vocabulary incidentally via verbal dramatization of written texts. In this case, readers’ theatre (RT is used as a way to allow learners to engage in active reading so as to promote vocabulary learning. A total of 160 diploma students participated in this case study and they were divided equally into two groups, namely classroom reading (CR and RT groups. A proficiency test was first conducted to determine their vocabulary levels. Based on the test results, a story was selected as the reading material in the two groups. The CR group read the story through a normal reading lesson in class while the RT group was required to verbally dramatize the text through readers’ theatre activity. Then, a post-test based on vocabulary levels was carried out and the results were compared. The findings revealed that incidental learning was more apparent in the RT group and their ability to learn words from the higher levels was noticeable through higher accuracy scores. Although not conclusive, this study has demonstrated the potential of using readers’ theatre as a form of incidental vocabulary learning activity in ESL settings.

  3. Intrarenal Splenosis Diagnosed in an Incidentally Found Left Renal Mass

    Directory of Open Access Journals (Sweden)

    Eliza Lamin

    2015-09-01

    Full Text Available Intrarenal splenosis is very rare and its management is not well established. We present a patient in whom an enhancing left renal mass was incidentally detected on a Computerized tomographic (CT scan, concerning for renal cell carcinoma. However, the lesion was determined to represent intrarenal splenosis, confirmed by Technetium-99m (99mTc sulfur colloid scan and percutaneous biopsy, which revealed splenic tissue. This multimodal approach to diagnosis of an unusual condition spared the patient an invasive procedure.

  4. Delayed incidental diagnosis of postoperative extradural hematoma following ventriculoperitoneal shunt

    Directory of Open Access Journals (Sweden)

    Vinay Byrappa

    2015-01-01

    Full Text Available Ventriculo peritoneal (VP shunt uncommonly complicates as intracranial hematomas which can still occur in patients with a functioning VP shunt leading to a delay in the diagnosis which can be extremely dangerous and lead to adverse outcomes. We report a case of an incidental diagnosis of delayed post-operative EDH following VP shunt in an young adult patient with a right cerebellar lesion and highlight the need for meticulous post-operative neurological examination.

  5. Growth and dislocation studies of β-HMX.

    Science.gov (United States)

    Gallagher, Hugh G; Sherwood, John N; Vrcelj, Ranko M

    2014-01-01

    The defect structure of organic materials is important as it plays a major role in their crystal growth properties. It also can play a subcritical role in "hot-spot" detonation processes of energetics and one such energetic is cyclotetramethylene-tetranitramine, in the commonly used beta form (β-HMX). The as-grown crystals grown by evaporation from acetone show prismatic, tabular and columnar habits, all with {011}, {110}, (010) and (101) faces. Etching on (010) surfaces revealed three different types of etch pits, two of which could be identified with either pure screw or pure edge dislocations, the third is shown to be an artifact of the twinning process that this material undergoes. Examination of the {011} and {110} surfaces show only one type of etch pit on each surface; however their natural asymmetry precludes the easy identification of their Burgers vector or dislocation type. Etching of cleaved {011} surfaces demonstrates that the etch pits can be associated with line dislocations. All dislocations appear randomly on the crystal surfaces and do not form alignments characteristic of mechanical deformation by dislocation slip. Crystals of β-HMX grown from acetone show good morphological agreement with that predicted by modelling, with three distinct crystal habits observed depending upon the supersaturation of the growth solution. Prismatic habit was favoured at low supersaturation, while tabular and columnar crystals were predominant at higher super saturations. The twin plane in β-HMX was identified as a (101) reflection plane. The low plasticity of β-HMX is shown by the lack of etch pit alignments corresponding to mechanically induced dislocation arrays. On untwinned {010} faces, two types of dislocations exist, pure edge dislocations with b = [010] and pure screw dislocations with b = [010]. On twinned (010) faces, a third dislocation type exists and it is proposed that these pits are associated with pure screw dislocations with b = [010

  6. Congenital dislocation of knee with ipsilateral developmental dysplasia of hip

    Directory of Open Access Journals (Sweden)

    Sameer Kakar

    2017-01-01

    Full Text Available We present a rare case of a newborn having congenital knee dislocation (CDK with ipsilateral developmental dysplasia of hip (DDH. This case report shows how abnormal intrauterine pressure leads to dislocation of various joints in utero. We managed this conservatively with Pavlik Harness for DDH and serial corrective casting with manipulation for CDK with a satisfactory result after follow-up of 6 months.

  7. Open medial ankle dislocation without associated fracture: a case report.

    Science.gov (United States)

    Dlimi, F; Mahfoud, M; Berrada, M S; El Bardouni, A; El Yaacoubi, M

    2011-12-01

    Tibiotalar dislocation without associated fracture is a rare injury. We report a case of an unusual open medial ankle dislocation without any associated bony injury. After reduction and debridement under general anaesthesia, capsule suture and ligaments repair were performed. An external fixator was applied for ankle immobilization. After 3 years follow-up, functional results were excellent without signs of instability or degenerative arthritis. Copyright © 2011 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  8. recurrent traumatic posterior hip dislocation in labral avulsion

    African Journals Online (AJOL)

    2003; 54(3):520-529. 5. Dameron, T.B Jr. Bucket-handle tear of acetabular labrum accompanying posterior dislocation of the hip. J Bone Joint Surg Am. 1959; 41(1): 131-134. 6. Lieberman, J.R., Altchek, D.W. and Salvati,. E.A. Recurrent dislocation of a hip with a labral lesion: treatment with a modified Bankart-type repair.

  9. Posterior dislocation of the hip while playing basketball.

    Science.gov (United States)

    Tennent, T D; Chambler, A F; Rossouw, D J

    1998-12-01

    Injuries in basketball are usually to the ankles and knees. Dislocation of the hip is usually associated with severe trauma--for example, road traffic accidents. A case is reported here in which a 22 year old club basketball player slipped on landing from a jump shot, forcing him into a side splits position from which he sustained a posterior dislocation of the hip resulting in a sciatic nerve palsy.

  10. Lens dislocation has a possible relationship with laser iridotomy

    OpenAIRE

    Mutoh, Tetsuya; Barrette, Kevin F; Matsumoto, Yukihiro; Chikuda, Makoto

    2012-01-01

    Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 mo...

  11. Posterior dislocation of the hip while playing basketball

    Science.gov (United States)

    Tennent, T. D.; Chambler, A. F.; Rossouw, D. J.

    1998-01-01

    Injuries in basketball are usually to the ankles and knees. Dislocation of the hip is usually associated with severe trauma--for example, road traffic accidents. A case is reported here in which a 22 year old club basketball player slipped on landing from a jump shot, forcing him into a side splits position from which he sustained a posterior dislocation of the hip resulting in a sciatic nerve palsy. 




 PMID:9865411

  12. Posterior dislocation of the hip while playing basketball

    OpenAIRE

    Tennent, T. D.; Chambler, A. F.; Rossouw, D. J.

    1998-01-01

    Injuries in basketball are usually to the ankles and knees. Dislocation of the hip is usually associated with severe trauma--for example, road traffic accidents. A case is reported here in which a 22 year old club basketball player slipped on landing from a jump shot, forcing him into a side splits position from which he sustained a posterior dislocation of the hip resulting in a sciatic nerve palsy. 






  13. MANAGEMENT OF POSTERIOR DISLOCATED INTRAOCULAR LENSES IN A TERTIARY HOSPITAL

    OpenAIRE

    Shashidhar; Apoorva Mithrananda; Manasa Penumetcha; Shruthi Chandra

    2016-01-01

    BACKGROUND The aim of this study was to assess and compare the visual outcome of different approaches in the management of dislocated PCIOL. MATERIALS AND METHODS 20 eyes of 20 patients who underwent 3PPPV/anterior vitrectomy to refixate or IOL exchange for dislocation or subluxation of PCIOL from 2012 to 2015. SFIOLs were implanted in 12 patients, IOL refixation was done in four patients and four were left aphakic. This is a retrospective study of 20 eyes of 20 patients ...

  14. Ligamentous and capsular restraints to experimental posterior elbow joint dislocation

    DEFF Research Database (Denmark)

    Deutch, S.R.; Olsen, B.S.; Jensen, S.L.

    2003-01-01

    the anterior capsule and the lateral collateral ligament complex (LCLC), whereas in the flexed elbow the anterior capsule did not have a stabilizing effect. In flexed joint positions, the LCLC seems to be the only immediate stabilizer against PEFR, and thereby against posterolateral instability and possibly...... against posterior dislocation. The medial collateral ligament did not have any immediate stabilizing effect, but it prevented the final step of the posterior dislocation....

  15. Long-standing temporomandibular joint dislocation: A rare experience

    Directory of Open Access Journals (Sweden)

    Kapil Malik

    2017-01-01

    Full Text Available Long-standing temporomandibular joint (TMJ dislocations persist for more than a month are most challenging to treat. The management of such condition varies widely, from closed reduction to complicated surgical procedures. The choice of an appropriate methodology is questionable. At present, there are no standard rules or conventions for the ideal strategy in different circumstances. This paper attempts to present the experience of managing two cases of long-standing TMJ dislocations.

  16. Vacancy clusters, dislocations and brown colouration in diamond

    OpenAIRE

    Bangert, U.; Barnes, R.; Gass, M. H.; Bleloch, A. L.; Godfrey, I. S.

    2009-01-01

    Following on from the idea that clusters of vacancies are the origin of the featureless absorption and brown colouration in natural diamond, dislocations are shown to exhibit sub-bandgap absorption also. The vacancy cluster idea has arisen from theoretical predictions of π-bonded chains reconstructing the cluster surfaces and has been confirmed by energy loss studies. In contrast, bandgap states at dislocations are observed in brown and colourless diamonds alike, giving rise to weak absorptio...

  17. Modeling of dislocation channel width evolution in irradiated metals

    Science.gov (United States)

    Doyle, Peter J.; Benensky, Kelsa M.; Zinkle, Steven J.

    2018-02-01

    Defect-free dislocation channel formation has been reported to promote plastic instability during tensile testing via localized plastic flow, leading to a distinct loss of ductility and strain hardening in many low-temperature irradiated materials. In order to study the underlying mechanisms governing dislocation channel width and formation, the channel formation process is modeled via a simple stochastic dislocation-jog process dependent upon grain size, defect cluster density, and defect size. Dislocations traverse a field of defect clusters and jog stochastically upon defect interaction, forming channels of low defect-density. Based upon prior molecular dynamics (MD) simulations and in-situ experimental transmission electron microscopy (TEM) observations, each dislocation encounter with a dislocation loop or stacking fault tetrahedron (SFT) is assumed to cause complete absorption of the defect cluster, prompting the dislocation to jog up or down by a distance equal to half the defect cluster diameter. Channels are predicted to form rapidly and are comparable to reported TEM measurements for many materials. Predicted channel widths are found to be most strongly dependent on mean defect size and correlated well with a power law dependence on defect diameter and density, and distance from the dislocation source. Due to the dependence of modeled channel width on defect diameter and density, maximum channel width is predicted to slowly increase as accumulated dose increases. The relatively weak predicted dependence of channel formation width with distance, in accordance with a diffusion analogy, implies that after only a few microns from the source, most channels observed via TEM analyses may not appear to vary with distance because of limitations in the field-of-view to a few microns. Further, examinations of the effect of the so-called "source-broadening" mechanism of channel formation showed that its effect is simply to add a minimum thickness to the channel

  18. [Isolated traumatic dislocation of the extensor carpi ulnaris tendon].

    Science.gov (United States)

    Loty, B; Meunier, B; Mazas, F

    1986-01-01

    The authors describe one case of post-traumatic dislocation of the extensor carpi ulnaris tendon. They found eleven other cases reported in the literature. The type of lesion should be looked for in cases of trauma to the wrist without a bony lesion. The treatment should be surgical when function is impaired, either shortly after the initial trauma or if the dislocation becomes habitual. The aim is to reconstruct a tendon sheath. The results were generally satisfactory.

  19. On the connection of Taylor models and dislocation dynamics

    International Nuclear Information System (INIS)

    Raabe, D.

    1994-01-01

    An approach for the connection of Taylor-type models and dislocation dynamics is suggested. The applied Taylor model takes into account grain interactions, leading to only partial local strain relaxation. For two orientations the predicted active slip systems are hereafter subject to the simulation of three-dimensional dislocation dynamics which, however, takes place on a much smaller strain scale when compared to Taylor modelling. (au) (19 refs.)

  20. Incidental Learning of Melodic Structure of North Indian Music.

    Science.gov (United States)

    Rohrmeier, Martin; Widdess, Richard

    2017-07-01

    Musical knowledge is largely implicit. It is acquired without awareness of its complex rules, through interaction with a large number of samples during musical enculturation. Whereas several studies explored implicit learning of mostly abstract and less ecologically valid features of Western music, very little work has been done with respect to ecologically valid stimuli as well as non-Western music. The present study investigated implicit learning of modal melodic features in North Indian classical music in a realistic and ecologically valid way. It employed a cross-grammar design, using melodic materials from two modes (rāgas) that use the same scale. Findings indicated that Western participants unfamiliar with Indian music incidentally learned to identify distinctive features of each mode. Confidence ratings suggest that participants' performance was consistently correlated with confidence, indicating that they became aware of whether they were right in their responses; that is, they possessed explicit judgment knowledge. Altogether our findings show incidental learning in a realistic ecologically valid context during only a very short exposure, they provide evidence that incidental learning constitutes a powerful mechanism that plays a fundamental role in musical acquisition. Copyright © 2016 Cognitive Science Society, Inc.

  1. Incidental MRI Findings in Patients with Impaired Cognitive Function

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yoon Joon [Dept. of Radiology, College of Medicine, Inje University, Ilsan Paik Hospital, Goyang (Korea, Republic of)

    2013-01-15

    This study aims to evaluate the incidental findings on brain MRI of patients with cognitive function impairments. We analyzed magnetic resonance (MR) findings of 236 patients with decreased cognitive function. MR protocols include conventional T2 weighted axial images, fluid attenuated inversion recovery axial images, T1 weighted coronal 3-dimensional magnetization-prepared rapid acquisition of gradient echo and diffusion tensor images. We retrospectively evaluated the signal changes that suggest acute/subacute infarction and space occupying lesions which show mass effect. Incidental MR findings were seen in 16 patients. Nine patients (3.8%) showed increased signal intensity on trace map of diffusion tensor images suggesting acute/subacute infarctions. Space occupying lesions were detected in 7 patients, and 3 lesions (1.27%) had mass effect and edema and were considered clinically significant lesions that diminish cognitive functions. Several incidental MR findings were detected in patients with decreased cognitive function, and the incidence of aucte/subacute infarctions were higher. Proper evaluations of MRI in patients with impaired cognitive functions will be helpful in early detection and management of ischemic lesions and space occupying lesions.

  2. Clinicopathologic features of incidental prostatic adenocarcinoma in radical cystoprostatectomy specimens

    Directory of Open Access Journals (Sweden)

    Vuruskan Hakan

    2011-07-01

    Full Text Available Abstract Background The aim of this study is to review all features of incidentally discovered prostate adenocarcinoma in patients undergoing radical cystoprostatectomy for bladder cancer. Methods The medical charts of 300 male patients who underwent radical cystoprostatectomy for bladder cancer between 1997 and 2005 were retrospectively reviewed. The mean age of the patients was 62 (range 51-75 years. Results Prostate adenocarcinoma was present in 60 (20% of 300 specimens. All were acinar adenocarcinoma. Of these, 40 (66.7% were located in peripheral zone, 20 (33.3% had pT2a tumor, 12 (20% had pT2b tumor, 22(36.7% had pT2c and, 6 (10% had pT3a tumor. Gleason score was 6 or less in 48 (80% patients. Surgical margins were negative in 54 (90% patients, and tumor volume was less than 0.5 cc in 23 (38.3% patients. Of the 60 incidentally detected cases of prostate adenocarcinoma 40 (66.7% were considered clinically significant. Conclusion Incidentally detected prostate adenocarcinoma is frequently observed in radical cystoprostatectomy specimens. The majority are clinically significant.

  3. Deformation localization and dislocation channel dynamics in neutron-irradiated austenitic stainless steels

    Science.gov (United States)

    Gussev, Maxim N.; Field, Kevin G.; Busby, Jeremy T.

    2015-05-01

    The dynamics of deformation localization and dislocation channel formation were investigated in situ in a neutron-irradiated AISI 304 austenitic stainless steel and a model 304-based austenitic alloy by combining several analytical techniques including optic microscopy and laser confocal microscopy, scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy (TEM). Channel formation was observed at ∼70% of the polycrystalline yield stress of the irradiated materials (σ0.2). It was shown that triple junction points do not always serve as a source of dislocation channels; at stress levels below the σ0.2, channels often formed near the middle of the grain boundary. For a single grain, the role of elastic stiffness value (Young's modulus) in channel formation was analyzed; it was shown that in the irradiated 304 steels the initial channels appeared in "soft" grains with a high Schmid factor located near "stiff" grains with high elastic stiffness. The spatial organization of channels in a single grain was analyzed; it was shown that secondary channels operating in the same slip plane as primary channels often appeared at the middle or at one-third of the way between primary channels. The twinning nature of dislocation channels was analyzed for grains of different orientation using TEM. In the AISI 304 steel, channels in grains oriented close to 〈0 0 1〉||TA (tensile axis) and 〈1 0 1〉||TA were twin free and grain with 〈1 1 1〉||TA and grains oriented close to a Schmid factor maximum contained deformation twins.

  4. Slip, twinning, and fracture at a grain boundary in the L1/sub 2/ ordered structure: A. sigma. = 9 tilt boundary

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, M.H.; King, A.H.

    1988-09-01

    The role of interaction between slip dislocations and a ..sigma.. = 9 tilt boundary in localized microplastic deformation, cleavage, or intergranular fracture in the L1/sub 2/ ordered structure has been analyzed by using the anisotropic elasticity theory of dislocations and fracture. Screw superpartials cross slip easily at the boundary onto the (11-bar1) and the (001) planes at low and high temperatures, respectively. Transmission of primary slip dislocations onto the conjugate slip system occurs with a certain degree of difficulty, which is eased by localized disordering. When the transmission is impeded, cleavage fracture on the (1-bar11) plane is predicted to occur, not intergranular fracture, unless a symmetric double pileup occurs simultaneously. Absorption (or emission) of superpartials occurs only when the boundary region is disordered. Slip initiation from pre-existing sources near the boundary can occur under the local stress concentration. Implications of the present result on the inherent brittleness of grain boundaries in Ni/sub 3/ Al and its improvement by boron segregation are discussed.

  5. Proximal interphalangeal joint dislocations and treatment: an evolutionary process.

    Science.gov (United States)

    Joyce, Kenneth Michael; Joyce, Cormac Weekes; Conroy, Frank; Chan, Jeff; Buckley, Emily; Carroll, Sean Michael

    2014-07-01

    Proximal interphalangeal joint (PIPJ) dislocations represent a significant proportion of hand clinic visits and typically require frequent follow-ups for clinical assessment, orthotic adjustments, and physiotherapy. There are a large number of treatment options available for PIPJ dislocations, yet no prospective or controlled studies have been carried out, largely due to the diversity of the various types of injuries. We retrospectively reviewed all the PIPJ dislocations in our institution over a five-year period and directly compared the different splinting techniques that we have used over this time frame. There were a total of 77 dislocations of the PIPJ (57 men and 20 women) that were included in our study. We found that our management has shifted gradually from complete immobilisation to controlled early mobilisation with figure-of-eight splints. Following treatment, the range of motion of the PIPJ in the figure-of-eight group was significantly greater than that in the other three methods (Ptreatment groups. The treatment of PIPJ dislocations has undergone a significant evolution in our experience. Early controlled mobilisation has become increasingly important, and therefore, splints have had to be adapted to allow for this. The figure-of-eight splint has yielded excellent results in our experience. It should be considered for all PIPJ dislocations, but careful patient selection is required to achieve optimum results.

  6. Dislocation-induced superfluidity in a model supersolid

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Debajit [Universitaet des Saarlandes, Saarbruecken (Germany); Dasbiswas, Kinjal; Dorsey, Alan [University of Florida, Gainesville, FL (United States); Yoo, Chi-Deuk [University of Minnesota, Minneapolis, MN (United States)

    2012-07-01

    Motivated by recent experiments on the supersolid behavior of {sup 4}He, we study the effect of an edge dislocation in promoting superfluidity in a Bose crystal. Using Landau theory, we couple the elastic strain field of the dislocation to the superfluid density, and use a linear analysis to show that superfluidity nucleates on the dislocation before occurring in the bulk of the solid. Moving beyond the linear analysis, we develop a systematic perturbation theory in the weakly nonlinear regime, and use this method to integrate out transverse degrees of freedom and derive a one-dimensional Landau equation for the superfluid order parameter. We then extend our analysis to a network of dislocation lines, and derive an XY model for the dislocation network by integrating over fluctuations in the order parameter. Our results show that the ordering temperature for the network has a sensitive dependence on the dislocation density, consistent with numerous experiments that find a clear connection between the sample quality and the supersolid response.

  7. Proximal Interphalangeal Joint Dislocations and Treatment: An Evolutionary Process

    Directory of Open Access Journals (Sweden)

    Kenneth Michael Joyce

    2014-07-01

    Full Text Available Background Proximal interphalangeal joint (PIPJ dislocations represent a significant proportion of hand clinic visits and typically require frequent follow-ups for clinical assessment, orthotic adjustments, and physiotherapy. There are a large number of treatment options available for PIPJ dislocations, yet no prospective or controlled studies have been carried out, largely due to the diversity of the various types of injuries. Methods We retrospectively reviewed all the PIPJ dislocations in our institution over a five-year period and directly compared the different splinting techniques that we have used over this time frame. Results There were a total of 77 dislocations of the PIPJ (57 men and 20 women that were included in our study. We found that our management has shifted gradually from complete immobilisation to controlled early mobilisation with figure-of-eight splints. Following treatment, the range of motion of the PIPJ in the figure-of-eight group was significantly greater than that in the other three methods (P<0.05 used. There were significantly fewer hospital visits in the figure-of-eight splint group than in the other treatment groups. Conclusions The treatment of PIPJ dislocations has undergone a significant evolution in our experience. Early controlled mobilisation has become increasingly important, and therefore, splints have had to be adapted to allow for this. The figure-of-eight splint has yielded excellent results in our experience. It should be considered for all PIPJ dislocations, but careful patient selection is required to achieve optimum results.

  8. Interstitial impurity interactions and dislocation microdynamics in Mo crystals

    International Nuclear Information System (INIS)

    Kwok, D.N.

    1975-05-01

    The effects of interstitial impurities on the mechanical properties of molybdenum are explored by comparing results obtained for crystals of various interstitial contents controlled by ultra-high vacuum outgassing. Results show a modulus reduction for as-grown samples and for outgassed specimens at low applied stresses. As a function of plastic microstrain, the values of modulus defect for both as-grown and outgassed specimens saturate at the same value. Interstitial impurities act as pinning agents to dislocation bowing, but when all the easy dislocation loops have broken away from local interstitial pins, the modulus defect reaches a constant saturation value. Etch pitting techniques were used to correlate microstrain observations with dislocation generation and motion. It has been found that edge dislocation generation and movement are active in the microstrain region while screw dislocations are relatively inactive until the macrostrain region is reached. Dislocation velocities range from 10 -6 to 10 -3 cm/s and the average distance between interstitial impurity pinning points is found to be approximately 8 x 10 -4 cm. (U.S.)

  9. Intraocular lens dislocation after whole-body vibration.

    Science.gov (United States)

    Vela, José I; Andreu, David; Díaz-Cascajosa, Jesús; Buil, José A

    2010-10-01

    We present 2 cases of intraocular lens (IOL) dislocation that appeared shortly after the patients exercised on a vibration platform. The first patient was a 71-year-old woman who presented with lens subluxation in her right eye and a complete posterior IOL dislocation in her left eye. The second case was a 62-year-old woman who presented with unilateral IOL dislocation within the capsular bag in her right eye. Timing from IOL implantation to dislocation was approximately 6 years and 4 years, respectively. Pars plana vitrectomy with removal of the dislocated IOL was performed in both patients. Whole-body vibration training has become increasingly popular as a form of exercise training. It reportedly may provide benefits in physical function and in some diseases, especially in older people. However, evidence-based protocols ensuring safety and efficacy in this population are lacking. We discuss vibration as a cause of late IOL dislocation. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Disassembly and Dislocation of a Bipolar Hip Prosthesis

    Directory of Open Access Journals (Sweden)

    Hsieh-Hsing Lee

    2008-01-01

    Full Text Available Dislocation of a hip prosthesis is a common complication. In usual cases of hip prosthesis dislocation, the prosthetic femoral head comes out from either the natural acetabular cavity in a bipolar hemiarthroplasty or the prosthetic acetabulum in a total hip arthroplasty. Only a few cases of bipolar hip prosthesis dislocation due to dissociation between the polyethylene and inner head of the prosthesis have been reported. We describe a rare case of disassembly of the inner head from the bipolar outer prosthesis in an osteoarthritic acetabulum. A 72-year-old woman had undergone bipolar hemiarthroplasty due to fracture of the left femoral neck about 10 years previously. Recently, she sustained an injury after falling from a chair, and examinations revealed an unusual disassembly−dislocation of the bipolar hip prosthesis. We classified this failure in our patient as a type II failure, representing extreme varus position of the outer head in the acetabulum, dislocation of the inner head from the outer head, and a detached locking ring around the stem neck. This mechanism of failure as shown in our patient rarely occurs in the bipolar prosthesis of the self-centering system. Osteoarthritic change of the acetabulum would place the outer head in the varus position, increasing wear on the beveled rim by impinging the femoral stem neck and causing dislodgment of the inner locking ring and consequent disassembly−dislocation of the inner head.

  11. Dislocation Starvation and Exhaustion Hardening in Mo-alloy Nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Claire [University of California, Berkeley & LBNL; Bei, Hongbin [ORNL; Lowry, M. B. [University of California, Berkeley; Oh, Jason [Hysitron, Inc., MN; Asif, S.A. Syed [Hysitron, Inc., MN; Warren, O. [Hysitron, Inc., MN; Shan, Zhiwei [Xi' an Jiaotong University, China & Hysitron, Inc., MN; George, Easo P [ORNL; Minor, Andrew [University of California, Berkeley & LBNL

    2012-01-01

    The evolution of defects in Mo alloy nanofibers with initial dislocation densities ranging from 0 to 1.6 1014 m2 were studied using an in situ push-to-pull device in conjunction with a nanoindenter in a transmission electron microscope. Digital image correlation was used to determine stress and strain in local areas of deformation. When they had no initial dislocations the Mo alloy nanofibers suffered sudden catastrophic elongation following elastic deformation to ultrahigh stresses. At the other extreme fibers with a high dislocation density underwent sustained homogeneous deformation after yielding at much lower stresses. Between these two extremes nanofibers with intermediate dislocation densities demonstrated a clear exhaustion hardening behavior, where the progressive exhaustion of dislocations and dislocation sources increases the stress required to drive plasticity. This is consistent with the idea that mechanical size effects ( smaller is stronger ) are due to the fact that nanostructures usually have fewer defects that can operate at lower stresses. By monitoring the evolution of stress locally we find that exhaustion hardening causes the stress in the nanofibers to surpass the critical stress predicted for self-multiplication, supporting a plasticity mechanism that has been hypothesized to account for the rapid strain softening observed in nanoscale bcc materials at high stresses.

  12. [Experimental study of dislocations of the scapulohumeral joint].

    Science.gov (United States)

    Gagey, O; Gagey, N; Boisrenoult, P; Hue, E; Mazas, F

    1993-01-01

    One may produce easily an experimental dislocation (anterior or erecta) of the scapulohumeral joint. The authors discuss, the experimental model then they describe the anatomical lesion produced through the experimental dislocation of 32 shoulders and the correlation observed after RMI assessment of 24 recurrent dislocations. The tear of the inferior glenohumeral ligament is constant, in 20 per cent of the cases the tear lies on the anterior aspect of the glenoid, in the other cases the tear was found on its humeral side. Whatever the situation of the tear of the inferior glenohumeral ligament, the lesion of the labrum was constant. The erecta dislocation was produced with the same movement but with a particular tear of the glenohumeral ligament: the tear was longitudinal. The experimental dislocation needs, in 7 or 8 cases, a desinsertion of the deep aspect of the rotator cuff. The Hill Sachs lesion occurs when the humerus falls along the chest wall after the dislocation. In 50 per cent of the patients, MRI shows modifications of the cuff which are compatible with our results. Hills Sachs lesions appear to be constant after MRI examination.

  13. Effect of -bar 2 grain boundaries on plastic deformation of WC-Co cemented carbides

    Energy Technology Data Exchange (ETDEWEB)

    Ostberg, G. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)]. E-mail: gusto@fy.chalmers.se; Farooq, M.U. [Department of Materials and Manufacturing Technology, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Christensen, M. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Andren, H.-O. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Klement, U. [Department of Materials and Manufacturing Technology, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Wahnstroem, G. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)

    2006-01-25

    Cutting inserts of WC-6wt.% Co were investigated before and after plastic deformation. The deformation tests were performed with a turning operation under realistic, yet controlled, conditions. SEM studies showed that after deformation the WC skeleton structure had broken up and thin lamellae of binder phase had formed in less than 10% of the grain boundaries. Ab initio calculations showed that -bar 2 twist WC/WC boundaries have a high work of separation and the interface energy is not lowered by forming two Co/WC boundaries. Electron backscattered diffraction (EBSD) measurements showed an apparent increase in the relative occurrence of -bar 2 boundaries due to poor indexing of the deformed material. The accumulation of dislocations in general boundaries is held responsible for the difficulty in identifying them compared with -bar 2 boundaries. At the -bar 2 tilt boundary the grains have the glide planes {l_brace}101-bar 0{r_brace} in common and at the -bar 2 twist boundary there are three glide planes intersecting, which facilitate dislocation movements across the -bar 2 boundaries.

  14. Analysis And Assessment Of The Security Method Against Incidental Contamination In The Collective Water Supply System

    Directory of Open Access Journals (Sweden)

    Szpak Dawid

    2015-09-01

    Full Text Available The paper presents the main types of surface water incidental contaminations and the security method against incidental contamination in water sources. Analysis and assessment the collective water supply system (CWSS protection against incidental contamination was conducted. Failure Mode and Effects Analysis (FMEA was used. The FMEA method allow to use the product or process analysis, identification of weak points, and implementation the corrections and new solutions for eliminating the source of undesirable events. The developed methodology was shown in application case. It was found that the risk of water contamination in water-pipe network of the analyzed CWSS caused by water source incidental contamination is at controlled level.

  15. Misfit dislocations and phase transformations in high-T sub c superconducting films

    CERN Document Server

    Gutkin, M Y

    2002-01-01

    A theoretical model is suggested that describes the effects of misfit stresses on defect structures, phase content and critical transition temperature T sub c in high-T sub c superconducting films. The focus is placed on the exemplary case of YBaCuO films deposited onto LaSrAlO sub 4 substrates. It is theoretically revealed here that misfit stresses are capable of inducing phase transformations controlled by the generation of misfit dislocations in growing cuprate films. These transformations, in the framework of the suggested model, account for experimental data on the influence of the film thickness on phase content and critical temperature T sub c of superconducting cuprate films, reported in the literature. The potential role of stress-assisted phase transformations in suppression of critical current density across grain boundaries in high-T sub c superconductors is briefly discussed.

  16. Growth and instability of charged dislocation loops under irradiation in ceramic materials

    CERN Document Server

    Ryazanov, A I; Kinoshita, C; Klaptsov, A V

    2002-01-01

    We have investigated the physical mechanisms of the growth and stability of charged dislocation loops in ceramic materials with very strong different mass of atoms (stabilized cubic zirconia) under different energies and types of irradiation conditions: 100-1000 keV electrons, 100 keV He sup + and 300 keV O sup + ions. The anomalous formation of extended defect clusters (charged dislocation loops) has been observed by TEM under electron irradiation subsequent to ion irradiation. It is demonstrated that very strong strain field (contrast) near charged dislocation loops is formed. The dislocation loops grow up to a critical size and after then become unstable. The instability of the charged dislocation loop leads to the multiplication of dislocation loops and the formation of dislocation network near the charged dislocation loops. A theoretical model is suggested for the explanation of the growth and stability of the charged dislocation loop, taking the charge state of point defects. The calculated distribution...

  17. Management of primary anterior shoulder dislocations using immobilization.

    Science.gov (United States)

    Smith, Brent I; Bliven, Kellie C Huxel; Morway, Genoveffa R; Hurbanek, Jason G

    2015-05-01

    Reference/Citation : Paterson WH, Throckmorton TW, Koester M, Azar FM, Kuhn JE. Position and duration of immobilization after primary anterior shoulder dislocation: a systemic review and meta-analysis of the literature. J Bone Joint Surg Am. 2010;92(18):2924-2933. Does an optimum duration and position of immobilization after primary anterior shoulder dislocation exist for reducing recurrence rates? MEDLINE/PubMed, EMBASE, and Cochrane databases were searched up to December 2009 without limitations. The search terms for all databases used were shoulder AND dislocation and shoulder AND immobilization. Criteria used to include articles were (1) English language, (2) prospective level I or level II studies (according to Journal of Bone & Joint Surgery guidelines), (3) nonoperative management of initial anterior shoulder dislocation, (4) minimum follow-up of 1 year, and (5) rate of recurrent dislocation as a reported outcome. A standardized evaluation method was used to extract data to allow assessment of methods issues and statistical analysis to determine sources of bias. The primary outcome was the recurrence rate after nonoperative management of anterior shoulder dislocation. Additional data extracted and used in subanalyses included duration and position of immobilization and age at the time of initial dislocation. Data were analyzed to determine associations among groups using 2-tailed Fisher exact tests. For pooled categorical data, relative risk of recurrent dislocation, 95% confidence intervals, and heterogeneity using the I(2) statistic and χ(2) tests were calculated for individual studies. The Mantel-Haenszel method was used to combine studies and estimate overall relative risk of recurrent dislocation and 95% confidence intervals. The statistical difference between duration of immobilization and position was determined using z tests for overall effect. Pooled results were presented as forest plots. In the initial search of the databases, the authors

  18. Rigid supersymmetry with boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, D.V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Van Nieuwenhuizen, P. [State Univ. of New York, Stony Brook, NY (United States). C.N. Yang Inst. for Theoretical Physics

    2008-01-15

    We construct rigidly supersymmetric bulk-plus-boundary actions, both in x-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended F- or D-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle. (orig.)

  19. Rigid supersymmetry with boundaries

    International Nuclear Information System (INIS)

    Belyaev, D.V.; Van Nieuwenhuizen, P.

    2008-01-01

    We construct rigidly supersymmetric bulk-plus-boundary actions, both in x-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended F- or D-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle. (orig.)

  20. Toughening by nano-scaled twin boundaries in nanocrystals

    International Nuclear Information System (INIS)

    Zhou, Haofei; Qu, Shaoxing; Yang, Wei

    2010-01-01

    Joint enhancement on strength and toughness provides a cutting-edge research frontier for metals and alloys. Conventional strengthening methods typically lead to suppressed ductility and fracture toughness. In this study, large-scale atomic simulation on the fracture process is performed featuring nanocrystals embedded with nano-scaled twin boundaries (TBs). Four toughening mechanisms by nano-scaled TBs are identified: (i) crack blunting through dislocation accommodation along the nano-scaled TBs; (ii) crack deflection in a manner of intragranular propagation; (iii) daughter crack formation along the nano-scaled TBs that further enhances the toughness and (iv) curved TB planes owing to an excessive pileup of geometrically necessary dislocations. These toughening mechanisms jointly dictate the mechanical behavior of nano-structured materials, and provide insights into the application of nano-scaled TBs with an aim to simultaneously obtain enhanced strength and toughness. New approaches to introduce these coherent internal defects into the nanostructure of crystalline materials are also proposed

  1. Dislocation core structures in (0001) InGaN

    Energy Technology Data Exchange (ETDEWEB)

    Rhode, S. L.; Sahonta, S.-L.; Kappers, M. J.; McAleese, C.; Humphreys, C. J. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Horton, M. K. [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Haigh, S. J. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); SuperSTEM, STFC Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Pennycook, T. J. [SuperSTEM, STFC Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Dusane, R. O. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Moram, M. A. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

    2016-03-14

    Threading dislocation core structures in c-plane GaN and In{sub x}Ga{sub 1−x}N (0.057 ≤ x ≤ 0.20) films were investigated by aberration-corrected scanning transmission electron microscopy. a-type dislocations are unaffected by alloying with indium and have a 5/7-atom ring core structure in both GaN and In{sub x}Ga{sub 1−x}N. In contrast, the dissociation lengths of (a + c)-type dislocations are reduced, and new 7/4/9-atom ring and 7/4/8/5-atom ring core structures were observed for the dissociated (a + c)-type dislocations in In{sub x}Ga{sub 1−x}N, which is associated with the segregation of indium near (a + c)-type and c-type dislocation cores in In{sub x}Ga{sub 1−x}N, consistent with predictions from atomistic Monte Carlo simulations.

  2. Single crystal plasticity by modeling dislocation density rate behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Benjamin L [Los Alamos National Laboratory; Bronkhorst, Curt [Los Alamos National Laboratory; Beyerlein, Irene [Los Alamos National Laboratory; Cerreta, E. K. [Los Alamos National Laboratory; Dennis-Koller, Darcie [Los Alamos National Laboratory

    2010-12-23

    The goal of this work is to formulate a constitutive model for the deformation of metals over a wide range of strain rates. Damage and failure of materials frequently occurs at a variety of deformation rates within the same sample. The present state of the art in single crystal constitutive models relies on thermally-activated models which are believed to become less reliable for problems exceeding strain rates of 10{sup 4} s{sup -1}. This talk presents work in which we extend the applicability of the single crystal model to the strain rate region where dislocation drag is believed to dominate. The elastic model includes effects from volumetric change and pressure sensitive moduli. The plastic model transitions from the low-rate thermally-activated regime to the high-rate drag dominated regime. The direct use of dislocation density as a state parameter gives a measurable physical mechanism to strain hardening. Dislocation densities are separated according to type and given a systematic set of interactions rates adaptable by type. The form of the constitutive model is motivated by previously published dislocation dynamics work which articulated important behaviors unique to high-rate response in fcc systems. The proposed material model incorporates thermal coupling. The hardening model tracks the varying dislocation population with respect to each slip plane and computes the slip resistance based on those values. Comparisons can be made between the responses of single crystals and polycrystals at a variety of strain rates. The material model is fit to copper.

  3. A Galeazzi-variant type fracture-dislocation in adults.

    Science.gov (United States)

    Vaishya, Raju; Shrestha, Sundar Kumar; Vaish, Abhishek

    2013-01-01

    Fracture of either radius or ulna with a dislocation either at the proximal or distal radioulnar joint (DRUJ) is not a common injury and is inherently unstable. Here we report a case series, with both-bone forearm fractures associated with dislocation of DRUJ, as a Galeazzi-variant type fracture-dislocation, and try to analyze this injury pattern. The study was based on 6 patients having Galeazzi-variant type fracture-dislocation of different age (20 to 45 years). All fractures were closed type. Two fractures involved the same level and three fractures were at different levels of radius and ulna shaft. After thorough examination and investigations they were treated with limited contact dynamic compression plate without additional fixation for DRUJ. All cases were followed up for 24 weeks. The maximum incidence occurred in age group between 31 and 40 years. All the fractures of both radius and ulna were united in average time of 12 weeks. Range of motion of wrist and elbow, supination and pronation at final follow-up were normal. There was no subsequent re-subluxation or dislocation of the DRUJ in any of the cases. Galeazzi variant in adult is a new undescribed pattern of forearm with wrist injury. Stable open reduction and internal fixation of both-bone forearm fractures is mandatory, followed by 3 to 4 weeks of immobilization in a cast for the healing of disrupted DRUJ.

  4. Atomic structures of icosahedral phases of type F and dislocations

    International Nuclear Information System (INIS)

    Beauchesne, Jean-Tristan

    2008-01-01

    The object of this thesis is the study of atomic structures of icosahedral phases of type F and their dislocations. In this study, we have first built a prototypical structure that describes the already known F type icosahedral phases. In order to check it we synthesized some of the new compositions predicted by this model. This synthesis led to the discovery of two new quasi-periodical phases of the stoichiometry Al66,08Cu21,35Mn8,29Fe4,28. One of these phases is icosahedral (metastable) of type F and the other one is decagonal (stable). A F-IQC phase is present on these compounds that have a different composition with respect to the ones already studied for the system (Al,Pd,Fe). Globally, these experimental results on new icosahedral phases allowed to prove the viability of the model: on the three samples of new composition, two of them have shown the existence of icosahedral phases of type F and the third one has given a decagonal phase, in relation of canonical orientation with the icosahedral metastable phase (10-fold axis parallel with 5-fold axis). Using this reliable model, we have been able to introduce dislocations. We could thus provide the geometry of dislocations (outside the dislocation core) at atomic scale for F-IQC phases. On this structure we have also identified the distributions of phasons and given some elements of answer for the global dislocations moves. (author) [fr

  5. An Unexpected Complication of Hip Arthroplasty: Knee Dislocation

    Directory of Open Access Journals (Sweden)

    Serdar Yilmaz

    2015-01-01

    Full Text Available An increasing number of patients with hip fracture have been seen with osteoporosis associated with osteoarthritis. Although knee dislocation is related to high-energy trauma, low-grade injuries can also lead to knee dislocation which is defined as “ultra-low velocity dislocation.” The case reported here is of an 82-year-old patient who presented with a left intertrochanteric hip fracture. Partial arthroplasty was planned because of osteoporosis. In the course of surgery, degenerative arthritic knee was dislocated during the hip reduction maneuver with the application of long traction. The neurovascular examination was intact, but the knee was grossly unstable and was dislocated even in a brace; thus a hinged knee prosthesis was applied nine days after surgery. The patient was mobilized with crutches after the knee prosthesis but exercise tolerance was diminished. In conclusion, it should be emphasized that overtraction must be avoided during the hip reduction maneuver in patients with advanced osteoarthritic knee.

  6. Dislocation dynamics simulations of plasticity at small scales

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Caizhi [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests. The primary objective of this research is to use 3-D DD simulations to study the plastic deformation of nano- and micro-scale materials and understand the correlation between dislocation motion, interactions and the mechanical response. Specifically, to identify what critical events (i.e., dislocation multiplication, cross-slip, storage, nucleation, junction and dipole formation, pinning etc.) determine the deformation response and how these change from bulk behavior as the system decreases in size and correlate and improve our current knowledge of bulk plasticity with the knowledge gained from the direct observations of small-scale plasticity. Our simulation results on single crystal micropillars and polycrystalline thin films can march the experiment results well and capture the essential features in small-scale plasticity. Furthermore, several simple and accurate models have been developed following our simulation results and can reasonably predict the plastic behavior of small scale materials.

  7. 3D quantum liquid crystals by condensation of dislocation worldsheets

    Science.gov (United States)

    Beekman, Aron; Wu, Kai; Nissinen, Jaakko; Zaanen, Jan

    A solid can partially melt into a liquid crystal where rotational rigidity is maintained while translational symmetry is restored. The topological melting is caused by an unbinding of dislocations. We recently provided a comprehensive review of quantum dislocation-mediated melting in 2D (arXiv:1603.04254). Through a duality mapping, phonons turn into dual gauge fields mediating interactions between dislocations. Upon condensation of dislocations, the dual gauge fields undergo the Anderson-Higgs mechanism and become gapped, signaling the loss of shear rigidity. Here we extend this theory to three dimensions. Dislocations are now linelike objects, strings, tracing out worldsheets in spacetime, while the dual gauge-fields become two-form (Kalb-Ramond) fields. We obtain the Higgs phase of these two-form gauge fields. Translational symmetry can be restored in three, two or one directions leading to nematic, smectic or columnar quantum liquid crystals. We derive the spectrum of low-energy excitations and its linear response. Goldstone modes due to broken rotational symmetry as well as superconductivity emerge whenever translational symmetry is restored. The peculiar features of liquid-crystalline order can be probed by finite-momentum spectroscopy.

  8. Vacancy clusters, dislocations and brown colouration in diamond.

    Science.gov (United States)

    Bangert, U; Barnes, R; Gass, M H; Bleloch, A L; Godfrey, I S

    2009-09-09

    Following on from the idea that clusters of vacancies are the origin of the featureless absorption and brown colouration in natural diamond, dislocations are shown to exhibit sub-bandgap absorption also. The vacancy cluster idea has arisen from theoretical predictions of π-bonded chains reconstructing the cluster surfaces and has been confirmed by energy loss studies. In contrast, bandgap states at dislocations are observed in brown and colourless diamonds alike, giving rise to weak absorption, which resembles that theoretically predicted from shuffle dislocation segments. This, however, would not account for the degrees of brownness in the diamonds, but it suggests that if such shuffle segments exist, vacancies must have been present and moved to dislocations to create these configurations in the first place. The question arises, what happens to the vast number of vacancy clusters upon high pressure high temperature (HPHT) annealing, which renders the diamonds colourless. Our observations on natural brown diamonds after HPHT treatment suggest that vacancy clusters, trapped in the strain fields of dislocations, grow in size accompanied by a decrease in their numbers; this leads to much reduced optical absorption.

  9. BILATERAL ANTERIOR DISLOCATION OF SHOULDER WITH GREATER TUBEROSITY FRACTURE DUE TO HYPONATREMIA : A RARE PRESENTATION

    Directory of Open Access Journals (Sweden)

    Sivananda

    2015-01-01

    Full Text Available We here report a rare presentation of bilateral anterior dislocation of shoulder with associated fracture of greater tuberosity in a 38 year old male due to minor trauma which he sustained secondary to hyponatremia induced irritability. There was no associ ated rotator cuff tear which is often associated with BADS which makes this presentation unique. Unilateral dislocation of shoulder is a common condition which is frequently encountered in emergency trauma department. Anterior dislocation is more common th an posterior dislocation. However, simultaneous bilateral shoulder dislocations are usually posterior. Bilateral anterior dislocations with fractures of the greater tuberosity are even rarer and are usually associated with trauma or seizures

  10. Modeling of dislocation generation and interaction during high-speed deformation of metals

    DEFF Research Database (Denmark)

    Schiøtz, J.; Leffers, T.; Singh, B.N.

    2002-01-01

    Recent experiments by Kiritani et al. [1] have revealed a surprisingly high rate of vacancy production during highspeed deformation of thin foils of fcc metals. Virtually no dislocations are seen after the deformation. This is interpreted as evidence for a dislocation-free deformation mechanism...... for the generation of vacancies are investigated. The main process is found to be incomplete annihilation of segments of edge dislocations on adjacent slip planes. The dislocations are also seen to be participating in complicated dislocation reactions, where sessile dislocation segments are constantly formed...

  11. Incidental solid renal mass in a cadaveric donor kidney

    Directory of Open Access Journals (Sweden)

    R M Meyyappan

    2012-01-01

    Full Text Available The number of patients living with end-stage renal disease (ESRD is increasing in our country and demand for renal grafts is ever increasing. Cadaver renal transplantation is being established as a viable supplement to live transplantation. We present a case where a mass lesion was encountered in the donor kidney from a cadaver. Enucleation of the lesion was done and we proceeded with the grafting. Histopathological examination showed a ′Renomedullary interstitial cell tumour′, a rare benign lesion. Post transplant, the renal function recovered well and the patient is asymptomatic. Such incidental renal masses present an ethical dilemma to the operating surgeon.

  12. Clinical value of renal images obtained incidentally to bone scintigraphy

    International Nuclear Information System (INIS)

    Ohishi, Y.; Machida, T.; Miki, M.; Kido, A.; Tanaka, A.

    1982-01-01

    Various studies were made on 400 renal (including 325 clinical cases) observed during whole-body bone scintigraphy using 99mTc-MDP. Asymmetrical renal images in bone scintigrams were obtained from 40% of the urologic patients and 7.5% of the nonurologic patients. Out of the asymmetrical images of the urologic patients, 50% provided nonvisualized kidneys and 35% showed unilateral renal high accumulation. It can be said from the above that renal images incidentally obtained during whole-body bone scintigraphy should not be overlooked

  13. Irradiation creep induced anisotropy in a/2 dislocation populations

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1984-05-01

    The contribution of anisotropy in Burgers vector distribution to irradiation creep behavior has been largely ignored in irradiation creep models. However, findings on Frank loops suggest that it may be very important. Procedures are defined to identify the orientations of a/2 Burgers vectors for dislocations in face-centered cubic crystals. By means of these procedures the anisotropy in Burgers vector populations was determined for three Nimonic PE16 pressurized tube specimens irradiated under stress. Considerable anisotropy in Burgers vector population develops during irradiation creep. It is inferred that dislocation motion during irradiation creep is restricted primarily to a climb of a/2 dislocations on 100 planes. Effect of these results on irradiation creep modeling and deformation induced irradiation growth is considered

  14. Epitaxial strain relaxation by provoking edge dislocation dipoles

    Science.gov (United States)

    Soufi, A.; El-Hami, K.

    2018-02-01

    Thin solid films have been used in various devices and engineering systems such as rapid development of highly integrated electronic circuits, the use of surface coatings to protect structural materials in high temperature environments, and thin films are integral parts of many micro-electro-mechanical systems designed to serve as sensors, actuators. Among techniques of ultra-thin films deposition, the heteroepitaxial method becomes the most useful at nanoscale level to obtain performed materials in various applications areas. On the other hand, stresses that appeared during the elaboration of thin films could rise deformations and fractures in materials. The key solution to solve this problem at the nanoscale level is the nucleation of interface dislocations from free surfaces. By provoking edge dislocation dipoles we obtained a strain relaxation in thin films. Moreover, the dynamic of nucleation in edge dislocations from free lateral surfaces was also studied.

  15. Missed posterior shoulder dislocation with malunited proximal humerus fracture

    Directory of Open Access Journals (Sweden)

    Kumar Sunil

    2013-12-01

    Full Text Available 【Abstract】Posterior dislocation of the shoulder may be missed or neglected at initial presentation especially in developing countries. We present a case of 40-year-old In- dian man who had 3-month missed posterior dislocation of the right shoulder along with malunited fracture of the ana- tomical neck of the humerus. Open reduction and stabiliza- tion with modified McLaughlin procedure was performed. Rotational osteotomy of proximal humerus had to be per- formed as supplementary procedure to keep the humeral head stable in glenoid cavity during functional range of movements. The patient had excellent result of the shoulder at 3 years follow-up. Key words: Shoulder dislocation; Humerus; Osteotomy

  16. Interferometric SAR and land deformation. Analysis using the dislocation model; Interferometric SAR to chikaku hendo. Dislocation model wo mochiita kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, J.; Otaki, T.; Tanaka, A.; Miyazaki, Y. [Geological Survey of Japan, Tsukuba (Japan)

    1996-05-01

    The diastrophism by the earthquake-induced dislocation is investigated by interferometry (INSAR) which represents the diastrophism by the interference fringes of equiphase difference lines. A joint research group at Geographical Survey Institute and National Space Development Agency showed the diastrophism in the vicinity of the ground surfaces before and after the Hyogoken Nanbu Earthquake by the INSAR interference images in 1995. This paper discusses the effects of observation in the vision line direction from the satellite and dislocation parameters on the interference images. The dislocation model uses a slanted rectangular model in a semi-infinite medium, to calculate static displacements and strain distributions at the ground surface, when dislocation changes. It is found that the INSAR interference images, detecting displacements in the vision line direction from the satellite, significantly change as the vision line direction changes, and that the actual displacement cannot be given by the images alone. This paper also shows sensitivity of the interference images to the dislocation parameters. 3 refs., 9 figs., 1 tab.

  17. 31 CFR 594.512 - Payment of taxes and incidental fees to the Palestinian Authority.

    Science.gov (United States)

    2010-07-01

    ....512 Payment of taxes and incidental fees to the Palestinian Authority. Effective April 12, 2006, U.S. persons are authorized to pay taxes or fees to, and purchase or receive permits or public utility services... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Payment of taxes and incidental fees...

  18. 31 CFR 595.510 - Payment of taxes and incidental fees to the Palestinian Authority.

    Science.gov (United States)

    2010-07-01

    ... Payment of taxes and incidental fees to the Palestinian Authority. Effective April 12, 2006, U.S. persons are authorized to pay taxes or fees to, and purchase or receive permits or public utility services... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Payment of taxes and incidental fees...

  19. Does the Freedom of Reader Choice Affect Second Language Incidental Vocabulary Acquisition?

    Science.gov (United States)

    Reynolds, Barry Lee; Bai, Yi Ling

    2013-01-01

    In this study, the effect of freedom of reader choice on the incidental acquisition of vocabulary was investigated in English as a Foreign Language (EFL) reading classes. Despite advocating free extensive reading as a means of obtaining a native-like L2 vocabulary,existing studies investigating the incidental acquisition of vocabulary have not…

  20. Incidental L2 Vocabulary Acquisition "from" and "while" Reading: An Eye-Tracking Study

    Science.gov (United States)

    Pellicer-Sánchez, Ana

    2016-01-01

    Previous studies have shown that reading is an important source of incidental second language (L2) vocabulary acquisition. However, we still do not have a clear picture of what happens when readers encounter unknown words. Combining offline (vocabulary tests) and online (eye-tracking) measures, the incidental acquisition of vocabulary knowledge…

  1. 30 CFR 937.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 937.702 Section 937.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of Other...

  2. 30 CFR 947.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 947.702 Section 947.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... other minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of...

  3. 30 CFR 912.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 912.702 Section 912.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of Other...

  4. 30 CFR 933.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 933.702 Section 933.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... other minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of...

  5. 30 CFR 905.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 905.702 Section 905.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... other minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of...

  6. 30 CFR 942.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 942.702 Section 942.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of Other...

  7. 30 CFR 939.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 939.702 Section 939.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... other minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of...

  8. 30 CFR 921.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 921.702 Section 921.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... other minerals. Part 702 of the chapter, Exemption for Coal Extraction Incidental to the Extraction of...

  9. 30 CFR 910.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 910.702 Section 910.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of Other...

  10. 30 CFR 922.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 922.702 Section 922.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of Other...

  11. 30 CFR 941.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 941.702 Section 941.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... other minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of...

  12. 30 CFR 903.702 - Exemption for coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Exemption for coal extraction incidental to the extraction of other minerals. 903.702 Section 903.702 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION... minerals. Part 702 of this chapter, Exemption for Coal Extraction Incidental to the Extraction of Other...

  13. 30 CFR 750.21 - Coal extraction incidental to the extraction of other minerals.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Coal extraction incidental to the extraction of other minerals. 750.21 Section 750.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... RECLAMATION OPERATIONS ON INDIAN LANDS § 750.21 Coal extraction incidental to the extraction of other minerals...

  14. 75 FR 13498 - Small Takes of Marine Mammals Incidental to Specified Activities; Dumbarton Bridge Seismic...

    Science.gov (United States)

    2010-03-22

    ... of Marine Mammals Incidental to Specified Activities; Dumbarton Bridge Seismic Retrofit Project... pile driving associated with the Dumbarton Bridge Seismic Retrofit Project. DATES: Effective August 15... request from Caltrans to harass marine mammals incidental to the Dumbarton Bridge Seismic Retrofit Project...

  15. 75 FR 34700 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Coastal Commercial...

    Science.gov (United States)

    2010-06-18

    ... National Marine Sanctuary (MBNMS) to incidentally take, by Level B harassment only, California sea lions.... ADDRESSES: The LOA and supporting documentation are available for review in the Permits, Conservation, and... taking of California sea lions and Pacific harbor seals, by Level B harassment, incidental to commercial...

  16. Impact of lymphocytic thyroiditis on incidence of pathological incidental thyroid carcinoma.

    Science.gov (United States)

    Farrell, Eric; Heffron, Cynthia; Murphy, Matthew; O'Leary, Gerard; Sheahan, Patrick

    2017-01-01

    The purpose of this study was to investigate the impact of lymphocytic thyroiditis on incidence of incidental thyroid cancers. We conducted a retrospective review of 713 consecutive patients who underwent thyroidectomies. Incidental thyroid cancer was defined as an unexpected cancer discovered on pathological examination outside the index nodule undergoing preoperative cytology. We excluded 65 cases because of preoperative diagnosis of thyroid cancer, and 68 because of nonincidental cancer within the index nodule. Among the remaining 580 cases, there were 43 cases (7.4%) of incidental thyroid cancers. Incidental thyroid cancers were significantly associated with moderate/severe lymphocytic thyroiditis (relative risk = 2.5; p = .03). Sixteen of 56 patients with moderate/severe lymphocytic thyroiditis had Graves' disease, none of whom had incidental thyroid cancer. The risk of incidental thyroid cancer associated with moderate/severe lymphocytic thyroiditis was significantly higher in non-Graves' than patients with Graves' disease (p = .05). The risk of incidental thyroid cancer is significantly increased in patients with moderate/severe lymphocytic thyroiditis. Moderate/severe lymphocytic thyroiditis associated with Graves' disease seems to have a lower risk of incidental thyroid cancer. © 2016 Wiley Periodicals, Inc. Head Neck 39: 122-127, 2017. © 2016 Wiley Periodicals, Inc.

  17. 77 FR 65864 - Receipt of an Application for Incidental Take Permit (16230)

    Science.gov (United States)

    2012-10-31

    ... an Application for Incidental Take Permit (16230) AGENCY: National Marine Fisheries Service (NMFS... amended application for an incidental take permit (Permit) from the North Carolina Division of Marine... (Polomolobus mediocris), and catfishes (Ictalurus sp.). Large mesh gill net fisheries for flounder...

  18. Incidental learning and memory for food varied in sweet taste in children

    NARCIS (Netherlands)

    Laureati, M.; Pagliarini, E.; Mojet, J.; Köster, E.P.

    2011-01-01

    This experiment investigated incidental learning and memory in children (age 7–10 years) for three different foods (fruit juice, fruit purée and biscuit), varied in sweetness. Children (N = 286) were exposed to three target foods and 24 h later their incidental learning was tested for one of the

  19. 76 FR 11205 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Construction and...

    Science.gov (United States)

    2011-03-01

    ... Marine Mammals Incidental to Construction and Operation of a Liquefied Natural Gas Deepwater Port in the Gulf of Mexico AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... marine mammal species incidental to construction and operation of a liquefied natural gas (LNG) deepwater...

  20. 76 FR 80891 - Small Takes of Marine Mammals Incidental to Specified Activities; Cape Wind's High Resolution...

    Science.gov (United States)

    2011-12-27

    ... to non-tactical sonar sources used in conjunction with seismic surveys. The pseudo-random noise... request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens... authorization to incidentally take small numbers of marine mammals by harassment. Section 101(a)(5)(D...

  1. Approach to the management of incidental venous thromboembolic events in patients with cancer.

    Science.gov (United States)

    O'Connell, Casey L; Liebman, Howard A

    2014-11-01

    Venous thromboembolism (VTE) is a frequent clinical complication of cancer and its treatment. Although much of the epidemiologic data regarding this complication have been based on symptomatic events, the use of multidetector row CT scanner technology has led to increased identification of VTE on scans ordered primarily for staging or restaging of malignancy. These incidentally discovered VTEs are variously referred to in the literature as incidental, asymptomatic, unexpected, or unsuspected VTE. A recent guidance paper by the Hemostasis and Malignancy Subcommittee of the International Society on Thrombosis and Haemostasis provided recommendations regarding this terminology (now termed incidental) and reporting of incidental VTE for clinical trials. A growing number of retrospective and case-controlled reports have described the prevalence, prognostic implications, and treatment options for these incidentally discovered VTE events, and have reported similar clinical outcomes for patients with incidental and symptomatic VTE. Because most reported patients with incidental VTE have been treated in a manner similar to those with symptomatic events, the present recommendations, except in rare circumstances, support the use of standard anticoagulation in the management of incidental deep vein thrombosis and pulmonary embolism. Copyright © 2014 by the National Comprehensive Cancer Network.

  2. 46 CFR 276.1 - Partial repayment-incidental domestic trading.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Partial repayment-incidental domestic trading. 276.1 Section 276.1 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS AFFECTING...—incidental domestic trading. In every instance where a vessel, with respect to which a construction...

  3. 75 FR 67951 - Takes of Marine Mammals Incidental to Specified Activities; Piling and Structure Removal in...

    Science.gov (United States)

    2010-11-04

    ... mammals, by harassment, incidental to derelict creosote piling and structure removal within the Woodard... authorization to take, by harassment, small numbers of marine mammals incidental to derelict creosote piling and... restoration effort. The piles designated to be removed have been treated with creosote, a wood preservative...

  4. 75 FR 48941 - Takes of Marine Mammals Incidental to Specified Activities; Piling and Structure Removal in...

    Science.gov (United States)

    2010-08-12

    ..., by harassment, incidental to derelict creosote piling and structure removal within the Woodard Bay... incidental to derelict creosote piling and structure removal associated with a habitat restoration project... proposed project involves the removal of 615 creosote treated wood pilings and overwater creosoted...

  5. Incidental Vocabulary Learning in Second Language Acquisition: A Literature Review (Aprendizaje incidental de vocabulario en la adquisición de una segunda lengua: una revisión de literatura)

    Science.gov (United States)

    Restrepo Ramos, Falcon Dario

    2015-01-01

    This literature review aims to analyze previous studies that address the incidental learning of vocabulary in second language acquisition. The articles included in this literature review look into the understanding of vocabulary learning through incidental means, the relationship of reading and incidental vocabulary learning, and the strategies…

  6. Effect of head diameter on passive and active dynamic hip dislocation.

    Science.gov (United States)

    Bunn, Adam; Colwell, Clifford W; D'Lima, Darryl D

    2014-11-01

    Hip dislocation is a major short-term complication after total hip arthroplasty (THA). One factor thought to reduce the risk for dislocation is head size. We constructed subject-specific computer models to study the effect of head size on risk for postoperative dislocation. Femoral and acetabular geometry was constructed after segmenting CT scans of nine hips. CAD models of THA components with four head diameters (28, 32, 36, and 44 mm) were virtually implanted. Hip capsular ligaments were simulated using rigid-body ellipsoids connected by non-linear springs. Posterior dislocation was simulated during a rise from a low chair; anterior dislocation was simulated during a pivot activity. Intraoperative stability tests were simulated for anterior or posterior dislocation. While rising from a low chair (posterior dislocation) and during the pivot activity (anterior dislocation), increasing head size significantly increased hip flexion angle at dislocation and generated higher dislocation moments. Larger heads reduced the risk for dislocation. Intraoperative stability tests detected the relative increased resistance to dislocation despite differences in the absolute magnitude of moments. This model can be useful preclinical tool for assessing design changes, the effect of component placement, and the activity-based risk for dislocation. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  7. Video Analysis of Primary Shoulder Dislocations in Rugby Tackles.

    Science.gov (United States)

    Maki, Nobukazu; Kawasaki, Takayuki; Mochizuki, Tomoyuki; Ota, Chihiro; Yoneda, Takeshi; Urayama, Shingo; Kaneko, Kazuo

    2017-06-01

    Characteristics of rugby tackles that lead to primary anterior shoulder dislocation remain unclear. To clarify the characteristics of tackling that lead to shoulder dislocation and to assess the correlation between the mechanism of injury and morphological damage of the glenoid. Case series; Level of evidence, 4. Eleven elite rugby players who sustained primary anterior shoulder dislocation due to one-on-one tackling between 2001 and 2014 were included. Using an assessment system, the tackler's movement, posture, and shoulder and head position were evaluated in each phase of tackling. Based on 3-dimensional computed tomography, the glenoid of the affected shoulder was classified into 3 types: intact, erosion, and bone defect. Orientation of the glenoid defect and presence of Hill-Sachs lesion were also evaluated. Eleven tackles that led to primary shoulder dislocation were divided into hand, arm, and shoulder tackle types based on the site at which the tackler contacted the ball carrier initially. In hand and arm tackles, the tackler's shoulder joint was forcibly moved to horizontal abduction by the impact of his upper limb, which appeared to result from an inappropriate approach to the ball carrier. In shoulder tackles, the tackler's head was lowered and was in front of the ball carrier at impact. There was no significant correlation between tackle types and the characteristics of bony lesions of the shoulder. Although the precise mechanism of primary anterior shoulder dislocation could not be estimated from this single-view analysis, failure of individual tackling leading to injury is not uniform and can be caused by 2 main factors: failure of approach followed by an extended arm position or inappropriate posture of the tackler at impact, such as a lowered head in front of the opponent. These findings indicate that injury mechanisms should be assessed for each type of tackle, as it is unknown whether external force to the glenoid is different in each mechanism

  8. Bilateral Traumatic Anterior Dislocation of Shoulder – a rare entity

    Directory of Open Access Journals (Sweden)

    Yashavantha Kumar C

    2013-01-01

    Full Text Available Introduction: Bilateral shoulder dislocation are most commonly posterior type. These are most commonly due to seizure disorder and electrocution. Anterior shoulder dislocations occurring bilaterally without any predisposing factors are very rare. These types of injuries are due to trauma with a unique mechanism of injury. To best of our knowledge there are only few cases of similar kind are reported in literature. We hereby report a interesting case of posttraumatic, bilateral anterior dislocation of shoulder without associated fracture in a 45 old women without any predisposing pathoanatomy.Case Report: A 45-year-old women presented to casualty with sudden onset of pain and restriction of movement in both shoulders fallowing trauma. Immediately post trauma she had severe pain and restriction of both shoulders. On examination arms were abducted and externally rotated. Bilateral shoulder movements were painful and restricted . There was loss of round contour of shoulder with increased vertical diameter of axilla anteriorly. Radiological examination revealed bilateral anterior dislocation of the shoulders without any associated fractures. Closed reduction done by Milch technique after intraraticular lignocaine injection. MRI of bilateral shoulder showed no pathological lesion. Both shoulders were immobilized with a shoulder immobilizer for three weeks.Conclusion: Most of the bilateral shoulder dislocations are posterior type seen in seizure disorders. Bilateral traumatic anterior shoulder dislocations are rare and are seen as a result of unique mechanism of injury. In our case patient had a fall on her elbows causing forced extension. If diagnosed and treated promptly completely normal function of the shoulders can be restored.

  9. MANAGEMENT OF POSTERIOR DISLOCATED INTRAOCULAR LENSES IN A TERTIARY HOSPITAL

    Directory of Open Access Journals (Sweden)

    Shashidhar

    2016-10-01

    Full Text Available BACKGROUND The aim of this study was to assess and compare the visual outcome of different approaches in the management of dislocated PCIOL. MATERIALS AND METHODS 20 eyes of 20 patients who underwent 3PPPV/anterior vitrectomy to refixate or IOL exchange for dislocation or subluxation of PCIOL from 2012 to 2015. SFIOLs were implanted in 12 patients, IOL refixation was done in four patients and four were left aphakic. This is a retrospective study of 20 eyes of 20 patients with dislocated/subluxated PCIOLs in a tertiary hospital from 2012 to 2015. STATISTICAL ANALYSIS Paired t-test statistical method. RESULTS We retrospectively analysed hospital records of patients who had undergone three PPPV/anterior vitrectomy for posteriorly dislocated/subluxated IOLs 20 eyes of 20 patients were analysed. SFIOLs were implanted in 12 patients, IOL refixation was done in four patients and four were left aphakic. Postoperative BCVA of 6/12 or better was achieved in 66.67% in primary SFIOL, secondary SFIOL and IOL refixation groups. BCVA of <6/60 was seen in all patients left aphakic. Early and late complications were most in aphakic patients. IOL refixation procedure had minimum early and late complications. Subluxated PCIOLs do better than dislocated lens where a successful SFIOL was placed. CONCLUSION IOL refixation procedure has the least complication rate. Early complications of SFIOL management resolve with time. Thus, 3PPPV/anterior vitrectomy with SFIOL and IOL refixation procedures offer a novel approach towards visual rehabilitation of patients with subluxated or dislocated PCIOLs.

  10. Radiation-Enhanced Dislocation Glide: The Current Status of Research

    Science.gov (United States)

    Maeda, Koji

    Dislocations in most semiconductors exhibit radiation-enhanced dislocation glide (REDG) which is a cause of serious degradation in bipolar devices under forward biasing. Phenomenologically, REDG is characterized by the remarkable reduction of activation energy for glide velocity and the pre-exponential factor controlled by radiation intensity. Although the REDG shares features common with similar effects in point defects known as the recombination-enhanced defect reaction (REDR) that is well interpreted in terms of the phonon kick mechanism, it is not as yet established whether the REDG and the REDR share or not the same microscopic mechanism due to the lack of knowledge concerning electronic levels associated with the dislocations showing the REDG. Recent progress, however, has been achieved by studies of REDG in 4H-silicon carbide (4H-SiC) in which the dislocation component that exhibits the REDG is identified as 30°-Si(g) partial dislocation. Nevertheless, the driving force for the REDG in 4H-SiC is not the mechanical stress as in usual cases but an anomalous reversal of the sign of the Shockley stacking-fault (SSF) energy depending on the radiation intensity. An attempt was made in our recent experiments of photoinduced REDG to separate the intensity-dependent REDG effect and also the intensity-dependent driving force by simultaneous measurements of SSF expansion velocity (hence, the glide velocity of 30°-Si(g) partials) and the intensity of photoluminescence from the same SSFs (the latter allows us to deduce the driving force for the SSF expansion and hence the REDG). A comment, inspired by the studies of REDG in 4H-SiC, is given also to the mechanism of radiation-enhanced dislocation climb, another cause of degradation induced by minority-carrier injection.

  11. Clinical effectiveness of acupuncture for mandibular subluxation and dislocation.

    Science.gov (United States)

    Lu, Dominic P; Lu, Gabriel P; Lu, Po-Ming

    2010-01-01

    Dislocation or subluxation of mandible could occur suddenly without Patient's awareness of its forthcoming. Patient may discover suddenly during yawning, laughing, or when the mouth is wide open that he or she could not close the jaw. It may cause serve anxiety and apprehension, that may put the patient in such a nervous state that may worsen the condition, and also may spastically tense the muscles associated with dislocation. We treated 37 patients in the past and found that, although five patients could be manipulated to have their dislocated jaw reduced to the normal state, we found that a majority of the cases could not be manipulated without supplementing with other adjunctive methods such as acupuncture at the pertinent acupoints, or injections of local anesthetic around the temporomandibular joint area. Twenty-seven patients were successful to have the dislocation or subluxation reduced, five patients required local anesthetic for reduction and 1 patient had to have the reduction done in the operating room under deep sedation. We found acupuncture is valuable in reducing the mandibular subluxation and dislocation. Three acupoints in calming down the patients were a valuable aid during treatment. LI 4 which is known to reduce pain in head and neck region could increase pain threshold and decrease anxiety associated with discomfort encountered during reduction treatment. Additional acupoints such as P 6 (Neikuan), Ext 1 (Yintang), and H 7 (Shenmen) are valuable for the patients who are tense and nervous. Those acupoints are also could be utilizied as additional aid to ease the spasm of the muscles associated with subluxation and dislocation. Post-operative care includes stabilization at the head and neck region.

  12. Effects of microscopic boundary conditions on plastic deformations of small-sized single crystals

    DEFF Research Database (Denmark)

    Kuroda, Mitsutoshi; Tvergaard, Viggo

    2009-01-01

    The finite deformation version of the higher-order gradient crystal plasticity model proposed by the authors is applied to solve plane strain boundary value problems, in order to obtain an understanding of the effect of the higher-order boundary conditions. Numerical solutions are carried out...... for uniaxial plane strain compression of a single crystal block and for uniform pure bending of a single crystal foil. The compressed block has loading surfaces that are penetrable or impenetrable to dislocations. This allows for a study of the two types of higher-order boundaries available, and a significant...

  13. Boundary migration in a 3D deformed microstructure inside an opaque sample

    DEFF Research Database (Denmark)

    Zhang, Yubin; Budai, J D; Tischler, Jonathan Z.

    2017-01-01

    How boundaries surrounding recrystallization grains migrate through the 3D network of dislocation boundaries in deformed crystalline materials is unknown and critical for the resulting recrystallized crystalline materials. Using X-ray Laue diffraction microscopy, we show for the first time....... The results show that neither of these two parameters can explain the observed migration behavior. Instead we suggest that the subdivision of the deformed microstructure ahead of the boundary plays the dominant role. The present experimental observations challenge the assumptions of existing recrystallization...

  14. The mean free path of mobile dislocations in ionic crystals

    International Nuclear Information System (INIS)

    Alsem, W.H.M.

    1981-01-01

    In this thesis results are presented of investigations on dislocation motion in deforming NaCl single crystals using the technique of pulsed nuclear magnetic resonance. In particular, the spin-locking pulse sequence is used to measure Tsub(lrho), which is the spin-lattice relaxation time in the presence of a resonant rf magnetic field. Tsub(lrho) depends strongly on the mean free path L, which is covered by the dislocations during successive jumps between obstacles in their glide plane. (Auth.)

  15. Clavicular hook plate for acute of acromio clavicular dislocations

    International Nuclear Information System (INIS)

    Concha, Juan Manuel; Quintero, Jose E; Illera, Jose M; Cruz, Carlos Eduardo; Daza, Carmen

    2004-01-01

    The purpose of this study was to evaluate the outcome of surgical treatment of complete AC dislocations with the SYNTHES clavicular hook plate. 31 patients with acute type III AC dislocations were prospectively evaluated in Popayan and Pereira hospitals between November 2002 and December 2003. Clinical and radiographic control checkups were carried out at 2,3 and 4 weeks and monthly after up to six months, then again after one year. The patient satisfaction, by 8 weeks, all patients except one, had achieved full functional status. Overall subjective satisfaction was very good in all cases. The hook plate implant provides secure anatomic reduction with very good functional recovery satisfaction

  16. Non-traumatic posterior atlanto-occipital joint dislocation

    OpenAIRE

    Takechi, Yasuhiko; Iizuka, Haku; Sorimachi, Yasunori; Ara, Tsuyoshi; Nishinome, Masahiro; Takagishi, Kenji

    2010-01-01

    This report presents a case of non-traumatic posterior atlanto-occipital dislocation. A 36-year-old female was referred with a history of numbness of the extremities, vertigo and neck pain for 1 year. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. A lateral cervical radiograph in the neutral position demonstrated a posterior atlanto-occipital dislocation. A coronal view on a computed tomography (CT) reconstruction ima...

  17. The incidental binding of color and shape is insensitive to the perceptual load

    Directory of Open Access Journals (Sweden)

    Hugo Cezar Palhares Ferreira

    2016-01-01

    Full Text Available Abstract The binding of information in visual short-term memory may occur incidentally when irrelevant information for the task at hand is stored together with relevant information. We investigated the process of the incidental conjunction of color and shape (Exp1 and its potential association with the selection of relevant information to the memory task (Exp2. The results in Exp1 show that color and shape are incidentally and asymmetrically conjugated: color interferes with the recognition of shape; however, shape does not interfere with the recognition of color. In Exp2, we investigated whether an increase in perceptual load would eliminate the processing of irrelevant information. The results of this experiment show that even with a high perceptual load, the incidental conjunction is not affected, and color remains to interfere with shape recognition, suggesting that the incidental conjunction is an automatic process.

  18. Small Renal Masses: Incidental Diagnosis, Clinical Symptoms, and Prognostic Factors

    Directory of Open Access Journals (Sweden)

    F. M. Sánchez-Martín

    2008-01-01

    Full Text Available Introduction. The small renal masses (SRMs have increased over the past two decades due to more liberal use of imaging techniques. SRMs have allowed discussions regarding their prognostic, diagnosis, and therapeutic approach. Materials and methods. Clinical presentation, incidental diagnosis, and prognosis factors of SRMs are discussed in this review. Results. SRMs are defined as lesions less than 4 cm in diameter. SRM could be benign, and most malignant SMRs are low stage and low grade. Clinical symptoms like hematuria are very rare, being diagnosed by chance (incidental in most cases. Size, stage, and grade are still the most consistent prognosis factors in (RCC. An enhanced contrast SRM that grows during active surveillance is clearly malignant, and its aggressive potential increases in those greater than 3 cm. Clear cell carcinoma is the most frequent cellular type of malign SRM. Conclusions. Only some SRMs are benign. The great majority of malign SRMs have good prognosis (low stage and grade, no metastasis with open or laparoscopic surgical treatment (nephron sparing techniques. Active surveillance is an accepted attitude in selected cases.

  19. Acetabular cup position and risk of dislocation in primary total hip arthroplasty

    DEFF Research Database (Denmark)

    Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik

    2017-01-01

    Background and purpose - Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed...

  20. Imaging features of traumatic dislocation of the lumbosacral joint associated with disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Tohme-Noun, C.; Krainik, A.; Menu, Y. [Department of Radiology, Hopital Beaujon, AP HP, Universite Paris 7, Faculte de Medecine Bichat-Beaujon, Paris (France); Rillardon, L.; Guigui, P. [Department of Orthopedic Surgery, Hopital Beaujon, AP HP, Universite Paris 7, Faculte de Medecine Bichat-Beaujon, Paris (France); Feydy, A. [Department of Radiology, Hopital Beaujon, AP HP, Universite Paris 7, Faculte de Medecine Bichat-Beaujon, Paris (France); Department of Radiology, Hopital Beaujon, 100 avenue du General Leclerc, 92118, Clichy (France)

    2003-06-01

    Bilateral facet dislocation of the lumbosacral joint is an uncommon injury. We report on the imaging findings in a patient who had an acute disc herniation associated with a bilateral traumatic lumbosacral dislocation. (orig.)