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Sample records for impinging flow mimicking

  1. Flow Characteristics of Rectangular Underexpanded Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru YAGA; Yoshio KINJO; Masumi TAMASHIRO; Kenyu OYAKAWA

    2006-01-01

    In this paper, the flow fields of underexpanded impinging jet issued from rectangular nozzles of aspect ratio 1,3 and 5 are numerically and experimentally studied. Two dimensional temperature and pressure distributions are measured by using infrared camera and the combination of a pressure scanning device and a stepping motor, respectively. The variation of the stagnation pressure on the impinging plate reveals that a hystcretic phenomenon exists during the increasing and decreasing of the pressure ratio for the aspect ratio of 3.0 and 5.0. It is also found that the nozzle of aspect ratio 1.0 caused the largest total pressure loss pc/p0 = 0.27 at the pressure ratio of p0/pb, = 6.5, where pc is the stagnation center pressure on the wall, p0 the upstream stagnation pressure, pb the ambient pressure. The other two nozzles showed that the pressure loss pc / p0=0.52 and 0.55 were achieved by the nozzles of the aspect ratio 3,0 and 5.0, respectively. The comparison between the calculations and experiments is fairly good, showing the three dimensional streamlines and structures of the shock waves in the jets. However, the hysteresis of the pressure variations observed in the experiments between the pressure ratio of 3.5 and 4.5 cannot be confirmed in the calculations.

  2. NUMERICAL SIMULATION OF LAMINAR SQUARE IMPINGING JET FLOWS

    Institute of Scientific and Technical Information of China (English)

    CHEN Qing-guang; XU Zhong; WU Yu-lin; ZHANG Yong-jian

    2005-01-01

    A theoretical study has been undertaken to determine the flow characteristics associated with a three-dimensional laminar impinging jet issuing from a square pipe nozzle. Interesting flow structures around the jet are detected. The numerical result reveals the existence of four streamwise velocity off-center peaks near the impingement plate, which is different from the rectangular jet impingement. The mechanism of the formation of the off-center velocity peaks and the parameters affecting the flow-field characteristics are discussed by comparison of the computed results with different nozzle-to-plate spacings and Reynolds numbers.

  3. Gaskinetic Modeling on Dilute Gaseous Plume Impingement Flows

    Directory of Open Access Journals (Sweden)

    Chunpei Cai

    2016-12-01

    Full Text Available This paper briefly reviews recent work on gaseous plume impingement flows. As the major part of this paper, also included are new comprehensive studies on high-speed, collisionless, gaseous, circular jet impinging on a three-dimensional, inclined, diffuse or specular flat plate. Gaskinetic theories are adopted to study the problems, and several crucial geometry-location and velocity-direction relations are used. The final complete results include impingement surface properties such as pressure, shear stress, and heat flux. From these surface properties, averaged coefficients of pressure, friction, heat flux, moment over the entire flat plate, and the distance from the moment center to the flat plate center are obtained. The final results include accurate integrations involving the geometry and specific speed ratios, inclination angle, and the temperature ratio. Several numerical simulations with the direct simulation Monte Carlo method validate these analytical results, and the results are essentially identical. The gaskinetic method and processes are heuristic and can be used to investigate other external high Knudsen (Kn number impingement flow problems, including the flow field and surface properties for a high Knudsen number jet from an exit and flat plate of arbitrary shapes. The results are expected to find many engineering applications, especially in aerospace and space engineering.

  4. Unusual lesions mimicking impingement syndrome in the shoulder joint - Think medially

    Directory of Open Access Journals (Sweden)

    Rohit Singh

    2016-09-01

    These are unusual causes that should be considered when investigating classical impingement syndrome and particularly those who may have failed to respond to decompression surgery. They highlight the potential value of looking beyond the sub-acromial space for causal lesions and in these cases, at a time when limited ultrasound investigation has become increasingly popular; MRI has clearly played an important and was essential in planning surgery as these lesions would not have been identified on USS. Even though the symptoms were classical.

  5. On the origin of impinging tones at low supersonic flow

    CERN Document Server

    Wilke, Robert

    2016-01-01

    Impinging compressible jets may cause deafness and material fatigue due to immensely loud tonal noise. It is generally accepted that a feedback mechanism similar to the screech feedback loop is responsible for impinging tones. The close of the loop remained unclear. One hypothesis hold up in the literature explains the emanated sound with the direct interaction of vortices and the wall. Other explanations name the standoff shock oscillations as the origin of the tones. Using direct numerical simulations (DNS) we were able to identify the source mechanism for under-expanded impinging jets with a nozzle pressure ratio (NPR) of 2.15 and a plate distance of 5 diameters. We found two different types of interactions between vortices and shocks to be responsible for the generation of the impinging tones. They are not related to screech.

  6. Convective Heat Transfer Enhancement of a Rectangular Flat Plate by an Impinging Jet in Cross Flow

    Institute of Scientific and Technical Information of China (English)

    李国能; 郑友取; 胡桂林; 张治国

    2014-01-01

    Experiments were carried out to study the heat transfer performance of an impinging jet in a cross flow. Several parameters including the jet-to-cross-flow mass ratio (X=2%-8%), the Reynolds number (Red=1434-5735) and the jet diameter (d=2-4 mm) were explored. The heat transfer enhancement factor was found to increase with the jet-to-cross-flow mass ratio and the Reynolds number, but decrease with the jet diameter when other parameters maintain fixed. The presence of a cross flow was observed to degrade the heat transfer performance in respect to the effect of impinging jet to the target surface only. In addition, an impinging jet was confirmed to be capable of en-hancing the heat transfer process in considerable amplitude even though the jet was not designed to impinge on the target surface.

  7. Numerical Analysis of the Flow Field of an Inclined Turbulent Impinging Jet

    Institute of Scientific and Technical Information of China (English)

    WEI Hong-jing

    2013-01-01

    A three-dimensional numerical study has been applied to examine the effects of impinging angle of incline impinging jet on heat transfer and flow field characteristic. Other parameters such as nozzle to plate distance and jet velocity and temperature are also examined to investigate their influences on jet flow. The impinging angle in range of 900-650, the nozzle exit-to-plate spacing (H/D) in range of 2 to 10, the Reynolds number in range of 1.27x102 to 1.27x104 and the jet temperature in range of 323K to 773K have been considered in this project.

  8. Influence of Wall Position on Flow Characteristics of an Impinging Jet

    Directory of Open Access Journals (Sweden)

    Pratik Tiwari,

    2014-03-01

    Full Text Available The study intends physical insight into heterogeneous phenomena of efflux from a small opening impinging on a surface. The work aims at understanding the role of wall location and orientation on flow characteristics of an impinging jet. Experiments were performed on an existing cascade tunnel with flow ejected at a velocity of 37 m/s from a small opening of (30 cm × 9 cm and corresponding flow features were analyzed. Results show that outside the core region, the flow experiences a monotonic reduction with increase in distance along streamline and radial direction. The orientation of wall is more efficient in bringing substantial change when placed closer to the exit (low velocity losses. The wall orientation primarily governs the chances of strong flow deflection or back flow losses. Wall placed far away from exit results in diminishing returns with a critical value beyond which the flow characteristics become insensitive of wall orientation.

  9. Thermal Characterization of porous graphitic foam ? convection in impinging flow

    Energy Technology Data Exchange (ETDEWEB)

    Sultan, K [University of Western Ontario, The; DeGroot, CT [University of Western Ontario, The; Straatman, Anthony G [ORNL; Gallego, Nidia C [ORNL; Hangan, H [University of Western Ontario, The

    2009-01-01

    An experimental study has been undertaken to explore the convective heat transfer enhancement that can be achieved in an impinging airflow arrangement by bonding layers of graphitic foam to a heated metal substrate. The effects of foam protrusion, foam thickness and foam properties were explored in this study. The results show that surfaces with a layer of foam protruding upward with open edges had the highest convective enhancement over that of the bare substrate under the same conditions. For the protruding cases, convective enhancements of 30-70% were observed for airflows ranging from 7-11 m/s, for foam thicknesses in the range 2-10 mm. The highest enhancements were observed for foam specimens with the most open, interconnected void structure.

  10. Astrium Approach For Plume Flow And Impingement Of 10 N Bipropellant Thruster

    Science.gov (United States)

    Theroude, Christophe; Scremin, G.; Wartelski, Matias

    2011-05-01

    Plume impingement on spacecraft surfaces due to chemical propulsion is a major concern during satellite operations. Indeed, thrusters plume induces disturbing forces and torques, contamination as well as thermal fluxes on sensitive surfaces. These effects, that have to be accurately predicted, influence the satellite design: thrusters orientation, MLI design, instruments protections, etc. In order to implement an efficient process of analysis, Astrium uses a two steps approach: first the thruster undisturbed flow field is computed, then the impingement on spacecraft surfaces is evaluated. In this paper, Plumflow, the Astrium Satellites software for undisturbed thrusters’ plume computation, is presented. This software is made of several modules in order to accurately compute the flow field in the different parts of the plume. A first module computes the chemistry in the chamber, then Navier-Stokes equations are solved inside the nozzle where the flow is continuous. After that a DSMC code is used for the transitional regime near the thruster lip and finally an hybrid TPMC/source-flow method computes the free molecular far flow field. The studied case is the Astrium GmbH 10 N bipropellant thruster. Some comparisons are presented between Plumflow and Professor G.A. Bird DSMC software DS2V and with DLR experimental data. These comparisons have shown very satisfactory results. Finally, aiming at computing plume impingement, the plume flow field generated with Plumflow has been interfaced with Professor G.A. Bird 3D DSMC software DS3V. The plume impingement simulation is performed by introducing the undisturbed flow field at a boundary of DS3V computational domain. It allows us to evaluate thermal flux distribution due to Astrium 10 N thruster on a plate adjacent to the thruster and to compare with the Astrium plume impingement software.

  11. Flow characteristics in free impinging jet reactor by particle image velocimetry (PIV) investigation

    Science.gov (United States)

    Zhang, Jun; Liu, Youzhi; Qi, Guisheng; Jiao, Weizhou; Yuan, Zhiguo

    2016-08-01

    The flow characteristics in free impinging jet reactors (FIJRs) were investigated using particle image velocimetry (PIV). The effects of the Reynolds number (Re) and the ratio of jet distance to jet diameter (w/d) on flow behavior were discussed for equal volumetric flow rates of the two jets. The impingement plane, instantaneous velocity, mean velocity, and turbulent kinetic energy (TKE) distribution of FIJRs are measured from captured images using the PIV technique. As Re increases, the average diameter of the impingement plane linearly increases. The instability of the liquid is closely related to the jet velocity or the Re. However, the stagnation point is insensitive to the variation of the Re. The droplets break up from the turbulent liquid in the ‘wall-free’ environment of FIJRs, so that the liquid back-flow found in confined impinging jet reactors (CIJRs) is not observed. Increasing the Re from 1800-4100 or decreasing the w/d from 20-6 plays a similar role in increasing the TKE values and intensifying turbulence, which promotes the momentum transfer and mixing efficiency in FIJRs.

  12. Turbulent heat transfer for impinging jet flowing inside a cylindrical hot cavity

    Directory of Open Access Journals (Sweden)

    Halouane Yacine

    2015-01-01

    Full Text Available Convective heat transfer from an isothermal hot cylindrical cavity due to a turbulent round jet impingement is investigated numerically. Three-dimensional turbulent flow is considered in this work. The Reynolds stress second order turbulence model with wall standard treatment is used for the turbulence predictions the problem parameters are the jet exit Reynolds number, ranging from 2x104 to 105and the normalized impinging distance to the cavity bottom and the jet exit Lf, ranging from 4 to 35. The computed flow patterns and isotherms for various combinations of these parameters are analyzed in order to understand the effect of the cavity confinement on the heat transfer phenomena. The flow in the cavity is divided into three parts, the area of free jet, and the area of the jet interaction with the reverse flow and the semi-quiescent flow in the region of the cavity bottom. The distribution of the local and mean Nusselt numbers along the cavity walls for above combinations of the flow parameters are detailed. Results are compared against to corresponding cases for impinging jet on a plate for the case of the bottom wall. The analysis reveals that the average Nusselt number increases considerably with the jet exit Reynolds number. Finally, it was found that the average Nusselt number at the stagnation point could be correlated by a relationship in the form Nu=f(Lf,Re.

  13. Computational flow and heat transfer of a row of circular jets impinging on a concave surface

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, B.V.N.R.; Prasad, B.V.S.S.S. [Indian Institute of Technology Madras, Thermal Turbomachines Lab, Chennai (India)

    2008-04-15

    A computational investigation is carried out to study the flow and heat transfer from a row of circular jets impinging on a concave surface. The computational domain simulates the impingement cooling zone of a gas turbine nozzle guide vane. The parameters, which are varied in the study include jet Reynolds number (Re{sub d} = 5000-67800), inter-jet distance to jet diameter ratio (c/d = 3.33 and 4.67) and target plate distance to jet diameter ratio (H/d = 1, 3 and 4). The flow field, predicted with K-{omega} turbulence model and using Fluent 6.2.16, is characterized with the presence of a pair of counter rotating vortices, an upwash fountain flow and entrainment. The local pressure coefficient and Nusselt number variations along the concave plate are presented and these values are found to under predict the available experimental data by about 12%. (orig.)

  14. A study of Impinging Flow on a Rotating Disc

    Directory of Open Access Journals (Sweden)

    Horia DUMITRESCU

    2014-09-01

    Full Text Available This paper focuses on the behavior of the boundary-layer laminar flow produced by a large radius no-thickness disc which rotates inside an axial stream. Some early solutions are only known for the upstream flow field, but the details of the flow behind the disc are still obscure. A better understanding of the mechanisms and the properties of the shear layer close to disc is sought through the development of an analytic theory and then is completed by CFD computations. This article also shows that the basic flow on the leeward side of disc is mostly rotational-inviscid and only on in the neighborhood of the disc surface there is a viscous layer which rotates drawn by disc. The viscous layer containing a thin Ekman sublayer and a thicker essentially inviscid superlayer, governed by Taylor-Proudman theorem, can carry three possible actions: centrifugal (pumping mode, neutral mode and centripetal (suction mode. The action type depends on the relative importance of effects given by translation of the fluid (W and rotation of the disc (ΩR, defined by a rotating parameter (W/ΩR. The existence of such modes is connected to the amount of angular momentum transferred outside the Ekman sublayer. A CFD analysis was used to identify the vortex structure which is responsible for the angular momentum transfer from the rotating disc to an axial stream.

  15. Review of fluid flow and convective heat transfer within rotating disk cavities with impinging jet

    CERN Document Server

    Harmand, Souad; Poncet, Sébastien; Shevchuk, Igor V; 10.1016/j.ijthermalsci.2012.11.009

    2013-01-01

    Fluid flow and convective heat transfer in rotor-stator configurations, which are of great importance in different engineering applications, are treated in details in this review. The review focuses on convective heat transfer in predominantly outward air flow in the rotor-stator geometries with and without impinging jets and incorporates two main parts, namely, experimental/theoretical methodologies and geometries/results. Experimental methodologies include naphthalene sublimation techniques, steady state (thin layer) and transient (thermochromic liquid crystals) thermal measurements, thermocouples and infra-red cameras, hot-wire anemometry, laser Doppler and particle image velocimetry, laser plane and smoke generator. Theoretical approaches incorporate modern CFD computational tools (DNS, LES, RANS etc). Geometries and results part being mentioned starting from simple to complex elucidates cases of a free rotating disk, a single disk in the crossflow, single jets impinging onto stationary and rotating disk,...

  16. Axisymmetric rotational stagnation-point flow impinging on a rotating disk

    Science.gov (United States)

    Weidman, Patrick

    2015-12-01

    Agrawal's (Q J Mech Appl Math, 10:42-44, 1957) stagnation-point flow problem is extended to flow impingement normal to a uniformly rotating disk. This is the analog of the extension of Homann's (Z Angew Math Mech (ZAMM), 16:153-164, 1936) stagnation flow when impinging on a rotating disk as reported by Hannah (Rep Mem Aerosp Res Coun Lond 2772, 1947). While both oncoming stagnation flows are axisymmetric, in the far field Homann's stagnation flow is irrotational while Agrawal's is rotational. A similarity reduction of the Navier-Stokes equations yields a pair of coupled ordinary differential equations governed by a dimensionless rotation rate σ. Integrations were carried out up to σ = 30 beyond which the equations become stiff and solution independence of integration length cannot be ensured. Results for the radial and azimuthal shear stresses are presented along with the strength of the flow induced into the boundary layer and the thickness of the azimuthal flow boundary layer. Analytic results found at σ = 0 are shown to be in excellent agreement with the numerical calculations. Sample velocity profiles for the radial and azimuthal flows are presented.

  17. Imaging flow during impingement of differentially heated jets over a flat surface

    Energy Technology Data Exchange (ETDEWEB)

    Rathee, Yogender; Vinoth, B.R.; Panigrahi, P.K., E-mail: panig@iitk.ac.in; Muralidhar, K.

    2015-12-01

    Highlights: • We carried out experiments to model thermal striping phenomenon in LMFBR. • We examined temperature fluctuation in flow field using shadowgraphy. • We correlated the wall temperature fluctuations to flow fluctuations. • The PIV measurements showed a distinct recirculation zone for equal velocity jets. • Equal velocity jets show highest temperature fluctuations. - Abstract: The present study investigates thermal fluctuations occurring in the mixing region of two adjacent differentially heated water jets impinging on a horizontal stainless steel surface. The nozzle diameters of the individual jets are equal. The jets are immersed in a pool of water at the ambient temperature. The Reynolds number range considered in the experiments is 2.09 × 10{sup 3}–2.51 × 10{sup 4} for each jet, while the Richardson number is in the range of 9.58 × 10{sup −3}–1.38 × 10{sup −2}. Light intensity fluctuations in the interfacial region of the jets are imaged using the shadowgraph technique. Particle image velocimetry (PIV) has been carried out in a plane passing across the two jets. The effect of various flow rates near the nozzles and the impingement plate are visualized. Time-averaged and RMS temperature fluctuations on the exposed face of the impingement plate are measured using thermocouples. Spectra of light intensity fluctuations determined from the shadowgraph data are correlated with those in wall temperature. Light intensity spectra grow in amplitude in the flow direction, as additional jet instabilities set in. The spectra are broadband with distinct peaks, typical of high Reynolds number jets. Time-averaged and RMS wall temperature distribution are quite distinct from those of light intensity within the impinging jets. Consistent with a wall-jet behavior, the largest RMS wall temperature occurs near the stagnation point and decays away from it. The gradient in the time-averaged wall temperature is the highest for equal velocity jets and

  18. On the correspondence between flow structures and convective heat transfer augmentation for multiple jet impingement

    Science.gov (United States)

    Terzis, Alexandros

    2016-09-01

    The correspondence between local fluid flow structures and convective heat transfer is a fundamental aspect that is not yet fully understood for multiple jet impingement. Therefore, flow field and heat transfer experiments are separately performed investigating mutual-jet interactions exposed in a self-gained crossflow. The measurements are taken in two narrow impingement channels with different cross-sectional areas and a single exit design. Hence, a gradually increased crossflow momentum is developed from the spent air of the upstream jets. Particle image velocimetry (PIV) and liquid crystal thermography (LCT) are used in order to investigate the aerothermal characteristics of the channel with high spatial resolution. The PIV measurements are taken at planes normal to the target wall and along the centreline of the jets, providing quantitative flow visualisation of jet and crossflow interactions. Spatially resolved heat transfer coefficient distributions on the target plate are evaluated with transient techniques and a multi-layer of thermochromic liquid crystals. The results are analysed aiming to provide a better understanding about the impact of near-wall flow structures on the convective heat transfer augmentation for these complex flow phenomena.

  19. Reactive Impinging-Flow Technique for Polymer-Electrolyte-Fuel-Cell Electrode-Defect Detection

    Energy Technology Data Exchange (ETDEWEB)

    Zenyuk, Iryna V.; Englund, Nicholas; Bender, Guido; Weber, Adam Z.; Ulsh, Michael

    2016-11-15

    Reactive impinging flow (RIF) is a novel quality-control method for defect detection (i.e., reduction in Pt catalyst loading) in gas-diffusion electrodes (GDEs) on weblines. The technique uses infrared thermography to detect temperature of a nonflammable (<4% H2) reactive mixture of H2/O2 in N2 impinging and reacting on a Pt catalytic surface. In this paper, different GDE size defects (with catalyst-loading reductions of 25, 50, and 100%) are detected at various webline speeds (3.048 and 9.144 m min-1) and gas flowrates (32.5 or 50 standard L min-1). Furthermore, a model is developed and validated for the technique, and it is subsequently used to optimize operating conditions and explore the applicability of the technique to a range of defects. The model suggests that increased detection can be achieved by recting more of the impinging H2, which can be accomplished by placing blocking substrates on the top, bottom, or both of the GDE; placing a substrate on both results in a factor of four increase in the temperature differential, which is needed for smaller defect detection. Overall, the RIF technique is shown to be a promising route for in-line, high-speed, large-area detection of GDE defects on moving weblines.

  20. Numerical study of an impinging jet to a turbulent channel flow in a T-Junction configuration

    Science.gov (United States)

    Georgiou, Michail; Papalexandris, Miltiadis

    2016-11-01

    In this talk we report on Large Eddy Simulations of an impinging planar jet to a turbulent channel flow in a T-Junction configuration. Due to its capacity for mixing and heat transfer enhancement, this type of flow is encountered in various industrial applications. In particular, our work is related to the emergency cooling systems of pressurized water reactors. As is well known, this type of flow is dominated by a large separation bubble downstream the jet impingement location. Secondary regions of flow separation are predicted both upstream and downstream the impinging jet. We describe how these separation regions interact with the shear layer that is formed by the injection of the jet to the crossflow, and how they affect the mixing process. In our talk we further examine the influence of the jet's velocity to characteristic quantities of the jet, such as penetration length and expansion angle, as well as to the first and second-order statistics of the flow.

  1. Analogy Between Hydraulic Jump in Films Formed by Impinging Liquid Jet and Critical Flow in Internal Flows

    Institute of Scientific and Technical Information of China (English)

    Jaroslaw Mikielewicz

    2003-01-01

    Formulated are simple models for the flow in liquid film, formed by impinging jet, and a two-phase downward flow in pipe. The models are based on simplified equations of mass, momentum and energy. The solutions of such conservation equations may have regular points belonging to one integral curve only as well as turning points can be found amongst them, which refer to extreme values in the appropriate co-ordinate system. The solutions can also have singular points belonging to none or more than one integral curve. Both the turning and singular points have a clear physical meaning. They could be linked to critical flow conditions in the pipe flow or to the so-called hydraulic jump. Analogy existing between critical conditions in the pipe and the flow of liquid films formed by the liquid jet have been shown in the paper.

  2. Reactive impinging-flow technique for polymer-electrolyte-fuel-cell electrode-defect detection

    Science.gov (United States)

    Zenyuk, Iryna V.; Englund, Nicholas; Bender, Guido; Weber, Adam Z.; Ulsh, Michael

    2016-11-01

    Reactive impinging flow (RIF) is a novel quality-control method for defect detection (i.e., reduction in Pt catalyst loading) in gas-diffusion electrodes (GDEs) on weblines. The technique uses infrared thermography to detect temperature of a nonflammable (catalyst-loading reductions of 25, 50, and 100%) are detected at various webline speeds (3.048 and 9.144 m min-1) and gas flowrates (32.5 or 50 standard L min-1). Furthermore, a model is developed and validated for the technique, and it is subsequently used to optimize operating conditions and explore the applicability of the technique to a range of defects. The model suggests that increased detection can be achieved by recting more of the impinging H2, which can be accomplished by placing blocking substrates on the top, bottom, or both of the GDE; placing a substrate on both results in a factor of four increase in the temperature differential, which is needed for smaller defect detection. Overall, the RIF technique is shown to be a promising route for in-line, high-speed, large-area detection of GDE defects on moving weblines.

  3. Flow characteristics and heat transfer performances of a semi-confined impinging array of jets: effect of nozzle geometry

    Energy Technology Data Exchange (ETDEWEB)

    Dano, B.P.E.; Liburdy, J.A. [Oregon State Univ., Corvallis, OR (United States). Dept. of Mechanical Engineering; Kanokjaruvijit, Koonlaya [Imperial College, London (United Kingdom). Dept. of Mechanical Engineering

    2005-02-01

    The flow and heat transfer characteristics of confined jet array impingement with crossflow is investigated. Discrete impingement pressure measurements are used to obtain the jet orifice discharge flow coefficient. Digital particle image velocimetry (DPIV) and flow visualization are used to determine the flow characteristics. Two thermal boundary conditions at the impinging surface are presented: an isothermal surface, and a uniform heat flux, where thermocouple and thermochromic liquid crystal methods were used, respectively, to determine the local heat transfer coefficient. Two nozzle geometries are studied, circular and cusped ellipse. Based on the interaction with the jet impingement at the surface, the crossflow is shown to influence the heat transfer results. The two thermal boundary conditions differ in overall heat transfer correlation with the jet Reynolds number. Detailed velocity data show that the flow development from the cusped ellipse nozzle affects the wall region flow more than the circular nozzle, as influenced by the crossflow interactions. The overall heat transfer for the uniform heat flux boundary condition is found to increase for the cusped ellipse orifice. (Author)

  4. Predictions of flow and heat transfer in multiple impinging jets with an elliptic-blending second-moment closure

    NARCIS (Netherlands)

    Thielen, L.; Hanjalić, K.; Jonker, H.; Manceau, R.

    2005-01-01

    We present numerical computations of flow and heat transfer in multiple jets impinging normally on a flat heated surface, obtained with a new second-moment turbulence closure combined with an elliptic blending model of non-viscous wall blocking effect. This model provides the mean velocity and turbu

  5. Simulation of Flow and Heat Transfer of Mist/Air Impinging Jet on Grinding Work-Piece

    OpenAIRE

    Fan Jiang; Han Wang; Yijun Wang; Jianhua Xiang

    2016-01-01

    The numerical investigation is presented for flow and heat transfer on grinding work-piece with mist/air impinging jet by using DPM (discrete phase model) model. The tracks of the mist droplets show most of them are accumulated on the right surface of grinding zone, and can be influenced by the rotating speed of the grinding wheel, the position and the number of the jet nozzle. The mechanism model of enhance cooling by mist/air impinging jet is developed, which indicated the mist droplet is a...

  6. Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime.

    Science.gov (United States)

    Yagi, Takanobu; Sato, Ayaka; Shinke, Manabu; Takahashi, Sara; Tobe, Yasutaka; Takao, Hiroyuki; Murayama, Yuichi; Umezu, Mitsuo

    2013-05-01

    This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.

  7. SIMULATION OF THE TWO PHASE FLOW OF DROPLET IMPINGEMENT ON LIQUID FILM BY THE LATTICE BOLTZMANN METHOD

    Institute of Scientific and Technical Information of China (English)

    GUO Jia-hong; WANG Xiao-yong

    2012-01-01

    A Lattice Boltzmann Method (LBM) with two-distribution functions is employed for simulating the two-phase flow induced by a liquid droplet impinging onto the film of the same liquid on solid surface.The model is suitable for solution of twophase flow problem at high density and viscosity ratios of liquid to vapor and phase transition between liquid and its vapor.The roles of the vapor flow,the density ratio of liquid to vapor and the surface tension of the droplet in the splashing formation are discussed.It is concluded that the vapour flow induced by the droplet fall and splash in the whole impinging process may affect remarkably the splash behaviour.For the case of large density ratio of liquid to vapor a crown may engender after the droplet collides with the film.However,for the case of small density ratio of liquid to vapor a “bell” like splash may be observed.

  8. Multiple impinging jet arrays. An experimental study on flow and heat transfer

    NARCIS (Netherlands)

    Geers, L.F.G.

    2004-01-01

    Because of their high efficiency and their ability to provide high heat transfer rates, impinging jets are applied for rapid cooling and heating in a wide variety of industrial processes. However, the physical phenomena controlling the heat transfer from impinging jets are to a large degree unknown.

  9. Modular jet impingement assemblies with passive and active flow control for electronics cooling

    Science.gov (United States)

    Zhou, Feng; Dede, Ercan Mehmet; Joshi, Shailesh

    2016-09-13

    Power electronics modules having modular jet impingement assembly utilized to cool heat generating devices are disclosed. The modular jet impingement assemblies include a modular manifold having a distribution recess, one or more angled inlet connection tubes positioned at an inlet end of the modular manifold that fluidly couple the inlet tube to the distribution recess and one or more outlet connection tubes positioned at an outlet end of the modular manifold that fluidly coupling the outlet tube to the distribution recess. The modular jet impingement assemblies include a manifold insert removably positioned within the distribution recess and include one or more inlet branch channels each including an impinging slot and one or more outlet branch channels each including a collecting slot. Further a heat transfer plate coupled to the modular manifold, the heat transfer plate comprising an impingement surface including an array of fins that extend toward the manifold insert.

  10. Micro-Machined Flow Sensors Mimicking Lateral Line Canal Neuromasts

    Directory of Open Access Journals (Sweden)

    Hendrik Herzog

    2015-08-01

    Full Text Available Fish sense water motions with their lateral line. The lateral line is a sensory system that contains up to several thousand mechanoreceptors, called neuromasts. Neuromasts occur freestanding on the skin and in subepidermal canals. We developed arrays of flow sensors based on lateral line canal neuromasts using a biomimetic approach. Each flow sensor was equipped with a PDMS (polydimethylsiloxane lamella integrated into a canal system by means of thick- and thin-film technology. Our artificial lateral line system can estimate bulk flow velocity from the spatio-temporal propagation of flow fluctuations. Based on the modular sensor design, we were able to detect flow rates in an industrial application of tap water flow metering. Our sensory system withstood water pressures of up to six bar. We used finite element modeling to study the fluid flow inside the canal system and how this flow depends on canal dimensions. In a second set of experiments, we separated the flow sensors from the main stream by means of a flexible membrane. Nevertheless, these biomimetic neuromasts were still able to sense flow fluctuations. Fluid separation is a prerequisite for flow measurements in medical and pharmaceutical applications.

  11. Validation of a new blood-mimicking fluid for use in Doppler flow test objects

    NARCIS (Netherlands)

    Ramnarine, KV; Nassiri, DK; Hoskins, PR; Lubbers, J

    1998-01-01

    A blood-mimicking fluid (BMF) suitable for use in Doppler flow test objects is described and characterised, The BMF consists of 5 mu m diameter nylon scattering particles suspended in a fluid base of water, glycerol, dextran and surfactant, The acoustical properties of various BMF preparations were

  12. Simulation of Flow and Heat Transfer of Mist/Air Impinging Jet on Grinding Work-Piece

    Directory of Open Access Journals (Sweden)

    Fan Jiang

    2016-01-01

    Full Text Available The numerical investigation is presented for flow and heat transfer on grinding work-piece with mist/air impinging jet by using DPM (discrete phase model model. The tracks of the mist droplets show most of them are accumulated on the right surface of grinding zone, and can be influenced by the rotating speed of the grinding wheel, the position and the number of the jet nozzle. The mechanism model of enhance cooling by mist/air impinging jet is developed, which indicated the mist droplet is an key factor of affecting the heat transfer coefficient, and the increasing of mist droplet leads to significant enhancement of the cooling effect. The effects of the jet nozzle location, the nozzle diameter, and the nozzle number on flow and heat transfer coefficient are studied. The results show that the less nozzle distance and inclination angle, the greater nozzle diameter and number lead to greater heat transfer coefficient.

  13. Secondary peak in the Nusselt number distribution of impinging jet flows: A phenomenological analysis

    Science.gov (United States)

    Aillaud, P.; Duchaine, F.; Gicquel, L. Y. M.; Didorally, S.

    2016-09-01

    This paper focuses on a wall-resolved Large Eddy Simulation (LES) of an isothermal round submerged air jet impinging on a heated flat plate, at a Reynolds number of 23 000 (based on the nozzle diameter and the bulk velocity at the nozzle outlet) and for a nozzle to plate distance of two jet diameters. This specific configuration is known to lead to a non-monotonic variation of the temporal-mean Nusselt number as a function of the jet center distance, with the presence of two distinct peaks located on the jet axis and close to two nozzle diameters from the jet axis. The objectives are here twofold: first, validate the LES results against experimental data available in the literature and second to explore this validated numerical database by the use of high order statistics such as skewness and probability density functions of the temporal distribution of temperature and pressure to identify flow features at the origin of the second Nusselt peak. Skewness (Sk) of the pressure temporal distribution reveals the rebound of the primary vortices located near the location of the secondary peak and allows to identify the initiation of the unsteady separation linked to the local minimum in the mean heat transfer distribution. In the region of mean heat transfer enhancement, joint velocity-temperature analyses highlight that the most probable event is a cold fluid flux towards the plate produced by the passage of the vortical structures. In parallel, heat transfer distributions, analyzed using similar statistical tools, allow to connect the above mentioned events to the heat transfer on the plate. Thanks to such advanced analyses, the origin of the double peak is confirmed and connected to the flow dynamics.

  14. Investigation of the flow-field of two parallel round jets impinging normal to a flat surface

    Science.gov (United States)

    Myers, Leighton M.

    The flow-field features of dual jet impingement were investigated through sub-scale model experiments. The experiments were designed to simulate the environment of a Short Takeoff, and Vertical Landing, STOVL, aircraft performing a hover over the ground, at different heights. Two different dual impinging jet models were designed, fabricated, and tested. The Generation 1 Model consisted of two stainless-steel nozzles, in a tandem configuration, each with an exit diameter of approximately 12.7 mm. The front convergent nozzle was operated at the sonic Mach number of 1.0, while the rear C-D nozzle was generally operated supersonically. The nozzles were embedded in a rectangular flat plate, referred to as the lift plate, which represents a generic lifting surface. The lift plate was instrumented with 36 surface pressure taps, which were used to examine the flow entrainment and recirculation patterns caused by varying the stand-off distance from the nozzle exits to a flat ground surface. The stand-off distance was adjusted with a sliding rail frame that the ground plane was mounted to. Typical dimensionless stand-off distances (ground plane separation) were H/DR = 2 to 24. A series of measurements were performed with the Generation 1 model, in the Penn State High Speed Jet Aeroacoustics Laboratory, to characterize the basic flow phenomena associated with dual jet impingement. The regions of interest in the flow-field included the vertical jet plume(s), near impingement/turning region, and wall jet outwash. Other aspects of interest included the loss of lift (suckdown) that occurs as the ground plane separation distance becomes small, and azimuthal variation of the acoustic noise radiation. Various experimental methods and techniques were used to characterize the flow-field, including flow-visualization, pressure rake surveys, surface mounted pressure taps, laser Doppler velocimetry, and acoustic microphone arrays. A second dual impinging jet scale model, Generation 2

  15. Pulsed photoacoustic Doppler flow measurements in blood-mimicking phantoms

    Science.gov (United States)

    Brunker, J.; Beard, P.

    2011-03-01

    The feasibility of making spatially resolved measurements of blood flow using pulsed photoacoustic Doppler techniques has been explored. Doppler time shifts were quantified via cross-correlation of pairs of photoacoustic waveforms generated within a blood-simulating phantom using pairs of laser light pulses. The photoacoustic waves were detected using a focussed or planar PZT ultrasound transducer. For each flow measurement, a series of 100 waveform pairs was collected. Previous data processing methods involved rejection of poorly correlated waveform pairs; the modal velocity value and standard deviation were then extracted from the selected distribution of velocity measurements. However, the data selection criteria used in this approach is to some extent arbitrary. A new data analysis protocol, which involves averaging the 100 cross-correlation functions and thus uses all of the measured data, has been designed in order to prevent exclusion of outliers. This more rigorous approach has proved effective for quantifying the linear motion of micron-scale absorbers imprinted on an acetate sheet moving with velocities in the range 0.14 to 1.25 ms-1. Experimental parameters, such as the time separation between the laser pulses and the transducer frequency response, were evaluated in terms of their effect on the accuracy, resolution and range of measurable velocities. The technique was subsequently applied to fluid phantoms flowing at rates less than 5 mms-1 along an optically transparent tube. Preliminary results are described for three different suspensions of phenolic resin microspheres, and also for whole blood. Velocity information was obtained even under non-optimal conditions using a low frequency transducer and a low pulse repetition frequency. The distinguishing advantage of pulsed rather than continuous-wave excitation is that spatially resolved velocity measurements can be made. This offers the prospect of mapping flow within the microcirculation and thus

  16. Flow pulsation in the near-wall layer of impinging jets

    Science.gov (United States)

    Tesař, V.

    2013-04-01

    Pulsation of impinging jets promises to become a useful way towards achieving the highest possible rate of passive scalar convective transport between fluid and a wall. Author investigated experimentally steady and pulsated impingement by hot-wire anemometer traversing along a radial line at a small height above the impingement wall. The data have shown two conspicuous local maxima of fluctuation intensity. In an attempt to reach understanding of these phenomena, numerical flowfield computations were also made, fitted to the experimental conditions. Despite simplification (isotropic handling of unsteadiness, eddies computed as Reynolds-type phase averages) the synergetic approach (experiment & computation) revealed interesting correlation and resulted in useful interpretations of the old problem of the off-axis extremes - and also brings new views on their behaviour in the pulsating jet case.

  17. Femoroacetabular impingement

    Energy Technology Data Exchange (ETDEWEB)

    Kassarjian, Ara [Department of Radiology, Division of Musculoskeletal Radiology, Massachusetts General Hospital, Boston, MA (United States)]. E-mail: akassarjian@partners.org; Brisson, Melanie [Department of Radiology, Centre Hospitalier Universitaire de Quebec, Que. (Canada); Palmer, William E. [Department of Radiology, Division of Musculoskeletal Radiology, Massachusetts General Hospital, Boston, MA (United States)

    2007-07-15

    Femoroacetabular impingement is a relatively recently appreciated 'idiopathic' cause of hip pain and degenerative change. Two types of impingement have been described. The first, cam impingement, is the result of an abnormal morphology of the proximal femur, typically at the femoral head-neck junction. Cam impingement is most common in young athletic males. The second, pincer impingement, is the result of an abnormal morphology or orientation of the acetabulum. Pincer impingement is most common in middle-aged women. This article reviews the imaging findings of cam and pincer type femoroacetabular impingement. Recognition of these entities will help in the selection of the appropriate treatment with the goal of decreasing the likelihood of early degenerative change of the hip.

  18. Validation of a new blood-mimicking fluid for use in Doppler flow test objects.

    Science.gov (United States)

    Ramnarine, K V; Nassiri, D K; Hoskins, P R; Lubbers, J

    1998-03-01

    A blood-mimicking fluid (BMF) suitable for use in Doppler flow test objects is described and characterised. The BMF consists of 5 microns diameter nylon scattering particles suspended in a fluid base of water, glycerol, dextran and surfactant. The acoustical properties of various BMF preparations were measured under uniform flow to study the effects of particle size, particle concentration, surfactant concentration, flow rate and stability. The physical properties, (density, viscosity and particle size), and acoustical properties (velocity, backscatter and attenuation) of the BMF are within draft International Electrotechnical Commission requirements.

  19. LES, RANS and combined simulation of impinging flows and heat transfer

    NARCIS (Netherlands)

    Hadziabdic, M.

    2006-01-01

    This thesis reports on a numerical study of a round, isothermal turbulent jet of incompressible fluid, impinging normally on a flat wall at a different temperature. The aim was to generate detailed information about the ime-dependent three-dimensional velocity and temperature field, and, based on

  20. Flow impinging effect of critical heat flux and nucleation boiling heat transfer on a downward facing heating surface

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Huai-En; Chen, Mei-Shiue; Chen, Jyun-Wei; Lin, Wei-Keng; Pei, Bau-Shei [National Tsing Hua Univ., Taiwan (China). Inst. of Nuclear Engineering and Science

    2015-05-15

    Boiling heat transfer has a high heat removal capability in convective cooling. However, the heat removal capability of downward-facing boiling is significantly worse than that of upward-facing cases because of the confined buoyancy effect. This study was inspired by the conception of external reactor vessel cooling (ERVC) condition relevant to the in-vessel retention (IVR) design of Westinghouse AP1000 plant. In the present study, a small-scale test facility had been established to investigate the local phenomena of boiling heat transfer under a downward-facing horizontal heated surface with impinging coolant flow. In this study, the surface temperature, heat flux information and several specific scenes of bubbles are taken down throughout the boiling processes for detailed investigation. It is observed that bubbles are confined under the downward-facing heated surface, which causes a worse heat transfer rate and a lower critical heat flux (CHF) limit than upward-facing boiling. Nevertheless, the impinging coolant flow is found to disturb the thermal boundary layer formed by the heated surface, so the CHF increases with an increase of coolant flow rate. In addition, during nucleate boiling, it is discovered that the growth, combination and dissipation of bubbles induce turbulent wakes and therefore enhance the heat transfer capability.

  1. Numerical study of metal foam heat sinks under uniform impinging flow

    Science.gov (United States)

    Andreozzi, A.; Bianco, N.; Iasiello, M.; Naso, V.

    2017-01-01

    The ever-increasing demand for performance improvement and miniaturization of electronics has led to a significant generation of waste heat that must be dissipated to ensure a reliable device operation. The miniaturization of the components complicates this task. In fact, reducing the heat transfer area, at the same required heat rate, it is necessary to increase the heat flux, so that the materials operate in a temperature range suitable to its proper functioning. Traditional heat sinks are no longer capable of dissipating the generated heat and innovative approaches are needed to address the emerging thermal management challenges. Recently, heat transfer in open-cell metal foams under an impinging jet has received attention due to the considerable heat transfer potential of combining two cooling technologies: impinging jet and porous medium. This paper presents a numerical study on Finned Metal Foam (FMF) and Metal Foam (MF) heat sinks under impinging air jet cooling. The analysis is carried out by means of the commercial software COMSOL Multiphysics®. The purpose is to analyze the thermal performance of the metal foam heat sink, finned or not, varying its geometric parameters. Results are presented in terms of predicted dissipated heat rate, convective heat transfer coefficient and pressure losses.

  2. Flow structure and heat transfer characteristics of an unconfined impinging air jet at high jet Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Ozmen, Y.; Baydar, E. [Karadeniz Technical University, Department of Mechanical Engineering, Trabzon (Turkey)

    2008-09-15

    The flow and heat transfer characteristics of an unconfined air jet that is impinged normally onto a heated flat plate have been experimentally investigated for high Reynolds numbers ranging from 30,000 to 70,000 and a nozzle-to-plate spacing range of 1-10. The mean and turbulence velocities by using hot-wire anemometry and impingement surface pressures with pressure transducer are measured. Surface temperature measurements are made by means of an infrared thermal imaging technique. The effects of Reynolds number and nozzle-to-plate spacing on the flow structure and heat transfer characteristics are described and compared with similar experiments. It was seen that the locations of the second peaks in Nusselt number distributions slightly vary with Reynolds number and nozzle-to-plate spacing. The peaks in distributions of Nusselt numbers and radial turbulence intensity are compatible for spacings up to 3. The stagnation Nusselt number was correlated for the jet Reynolds number and the nozzle-to-plate spacing as Nu{sub st}{proportional_to}Re {sup 0.69}(H/D){sup 0.019}. (orig.)

  3. APPLICATION OF TWO VERSIONS OF A RNG BASED k-ε MODEL TO NUMERICAL SIMULATIONS OF TURBULENT IMPINGING JET FLOW

    Institute of Scientific and Technical Information of China (English)

    Chen Qing-guang; Xu Zhong; Zhang Yong-jian

    2003-01-01

    Two independent versions of the RNG based k-ε turbulence model in conjunction with the law of the wall have been applied to the numerical simulation of an axisymmetric turbulent impinging jet flow field. The two model predictions are compared with those of the standard k-ε model and with the experimental data measured by LDV (Laser Doppler Velocimetry). It shows that the original version of the RNG k-ε model with the choice of Cε1=1.063 can not yield good results, among them the predicted turbulent kinetic energy profiles in the vicinity of the stagnation region are even worse than those predicted by the standard k-ε model. However, the new version of RNG k-ε model behaves well. This is mainly due to the corrections to the constants Cε1 and Cε2 along with a modification of the production term to account for non-equilibrium strain rates in the flow.

  4. Femoroacetabular impingement

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Suzanne E., E-mail: andersonsembach@yahoo.com.au [The University of Notre Dame Australia, School of Medicine Sydney, 160 Oxford Street, Darlinghurst 2010, NSW, Sydney (Australia); Department of Diagnostic, Pediatric and Interventional Radiology, Inselspital, University of Bern, Bern 3010 (Switzerland); Siebenrock, Klaus Arno; Tannast, Moritz [Department of Orthopedic Surgery, Inselspital, University of Bern, Bern 3010 (Switzerland)

    2012-12-15

    Femoroacetabular impingement (FAI) is a pathomechanical concept describing the early and painful contact of morphological changes of the hip joint, both on the acetabular, and femoral head sides. These can lead clinically to symptoms of hip and groin pain, and a limited range of motion with labral, chondral and bony lesions. Pincer impingement generally involves the acetabular side of the joint where there is excessive coverage of the acetabulum, which may be focal or more diffuse. There is linear contact of the acetabulum with the head/neck junction. Cam impingement involves the femoral head side of the joint where the head is associated with bony excrescences and is aspheric. The aspheric femoral head jams into the acetabulum. Imaging appearances are reviewed below. This type is evident in young males in the second and third decades. The main features of FAI are described.

  5. Performance of flowing in exterior circulative impinging stream reactor%撞击流反应器撞击区流动特性研究

    Institute of Scientific and Technical Information of China (English)

    李晓蓉; 郑燕萍; 孙勤; 杨阿三; 程榕

    2012-01-01

    The flow characteristics of impinging stream from an impinging stream reactor with 160 L effective capacity were studied. With water as medium and potassium chloride saturated solution as tracer, the influences of impinging velocity and nozzle distance on the concentration of tracer were measured by conductive method. The mean residence time distribution was simulated by a tanks-in-series model for calculating the exit concentration of the impinging area in the reactor. The calculated results show that the model can finely describe the residence time distribution and the exit concentration very well. The experimental results indicate that the number of tanks and the mean residence time decrease with the decrease of the nozzle distance, increase with the increase of impinging velocity. The flow in the reactor is complete mixed flow when impinging velocity is 2. 0 m/s. The macro-mixing process in the reactor is improved obviously when the impinging velocity is increased.%为研究撞击区的流动特性,在有效容积为160 L的撞击流反应器内,以水为介质,饱和KCl溶液为示踪剂,用电导法测定了不同导流筒出口间距和撞击流速下的示踪剂浓度曲线,并通过多釜串联模型拟合得到了撞击区的平均停留时间及模拟釜数.结果表明:导流筒出口间距减小,撞击流速增大,撞击区平均停留时间减小,釜数减小;撞击流速为2.0 m/s时,撞击区内流型接近于全混流.停留时间分布主要受撞击流速的影响,增大流速有利于促进撞击区中的宏观混合.

  6. Dual solutions in MHD stagnation-point flow of Prandtl fluid impinging on shrinking sheet

    Institute of Scientific and Technical Information of China (English)

    N.S.AKBAR; Z.H.KHAN; R.U.HAQ; S.NADEEM

    2014-01-01

    The present article investigates the dual nature of the solution of the magneto-hydrodynamic (MHD) stagnation-point flow of a Prandtl fluid model towards a shrinking surface. The self-similar nonlinear ordinary differential equations are solved numerically by the shooting method. It is found that the dual solutions of the flow exist for cer-tain values of the velocity ratio parameter. The special case of the first branch solutions (the classical Newtonian fluid model) is compared with the present numerical results of stretching flow. The results are found to be in good agreement. It is also shown that the boundary layer thickness for the second solution is thicker than that for the first solution.

  7. Heat and fluid flow properties of circular impinging jet with a low nozzle to plate spacing. Improvement by nothched nozzle; Nozzle heibankan kyori ga chiisai baai no enkei shototsu funryu no ryudo dennetsu tokusei. Kirikaki nozzle ni yoru kaizen kojo

    Energy Technology Data Exchange (ETDEWEB)

    Shakouchih, T. [Mie University, Mie (Japan). Faculty of Engineering; Matsumoto, A.; Watanabe, A.

    2000-10-25

    It is well known that as decreasing the nozzle to plate spacing considerably the heat transfer coefficient of circular impinging jet, which impinges to the plate normally, increases remarkably. At that time, the flow resistance of nozzle-plate system also increases rapidly. In this study, in order to reduce the flow resistance and to enhance the heat transfer coefficient of the circular impinging jet with a considerably low nozzle to plate spacing, a special nozzle with notches is proposed, and considerable improvement of the flow and heat transfer properties are shown. The mechanism of enhancement of the heat transfer properties is also discussed. (author)

  8. Experimental and numerical investigation of flow field and heat transfer from electronic components in a rectangular channel with an impinging jet

    Directory of Open Access Journals (Sweden)

    Calisir Tamer

    2015-01-01

    Full Text Available Thermal control of electronic components is a continuously emerging problem as power loads keep increasing. The present study is mainly focused on experimental and numerical investigation of impinging jet cooling of 18 (3 × 6 array flash mounted electronic components under a constant heat flux condition inside a rectangular channel in which air, following impingement, is forced to exit in a single direction along the channel formed by the jet orifice plate and impingement plate. Copper blocks represent heat dissipating electronic components. Inlet flow velocities to the channel were measured by using a Laser Doppler Anemometer (LDA system. Flow field observations were performed using a Particle Image Velocimetry (PIV and thermocouples were used for temperature measurements. Experiments and simulations were conducted for Re = 4000 – 8000 at fixed value of H = 10 × Dh. Flow field results were presented and heat transfer results were interpreted using the flow measurement observations. Numerical results were validated with experimental data and it was observed that the results are in agreement with the experiments.

  9. Study of Several Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Impinging Jets are frequently adapted for cooling overheated parts.With the film cooling technique,this process improves thermal exchanges between walls and fluid.However if many works have concerned only the thermal aspect of this problem[1],its dynamic field has been rarely studied especially for multiple impingements.As the two phenomena caanot be totally dissociated.we have undertaken the aerodynamic and thermal study of jets impinging on a aplane wall,Various techniques,have been used as visualizations(spreading over method.LASER sheet visualizations),LDA measurements to propose a topology schema of the flow and infraed thermography.

  10. Femoroacetabular impingement

    Directory of Open Access Journals (Sweden)

    José Batista Volpon

    Full Text Available ABSTRACT The femoroacetabular impingement (FAI is as condition recently characterized that results from the abnormal anatomic and functional relation between the proximal femur and the acetabular border, associated with repetitive movements, which lead labrum and acetabular cartilage injuries. Such alterations result from anatomical variations such as acetabular retroversion or decrease of the femoroacetabular offset. In addition, FAI may result from acquired conditions as malunited femoral neck fractures, or retroverted acetabulum after pelvic osteotomies. These anomalies lead to pathological femoroacetabular contact, which in turn create impact and shear forces during hip movements. As a result, there is early labrum injury and acetabulum cartilage degeneration. The diagnosis is based on the typical clinical findings and images. Treatment is based on the correction of the anatomic anomalies, labrum debridement or repair, and degenerate articular cartilage removal. However, the natural evolution of the condition, as well as the outcome from long-term treatment, demand a better understanding, mainly in the asymptomatic individuals.

  11. Noise generated by impingement of turbulent flow on airfoils of varied chord, cylinders, and other flow obstructions

    Science.gov (United States)

    Olsen, W. A.

    1976-01-01

    Noise spectra were measured in three dimensions for several surfaces immersed in turbulent flow from a jet and over a range of flow conditions. The data are free field and were corrected to remove the small contributions of jet noise, atmospheric attenuation and feedback tones. These broadband data were compared with the results of available theories which are only strictly applicable to simple geometries over a limited range of conditions. The available theories proved to be accurate over the range of flow, chord length, thickness, angle of attack, and surface geometries defined by the experiments. These results apply to the noise generated by fixed surfaces in engine passages, the lifting surfaces of aircraft and also to fan noise.

  12. Investigation on heat transfer mechanism of impinging jet with cross-flow%横流对冲击射流换热特性的影响

    Institute of Scientific and Technical Information of China (English)

    张传杰; 孙纪宁; 李浩; 毛宏霞

    2011-01-01

    用实验和数值计算的方法研究了横流对单孔短距冲击换热特性的影响规律.结果表明:①在实验研究范围内,冲击靶面平均努塞尔数Nuav,is随横流的增大而增大;②冲击靶面前区努塞尔数Nufia随横流的增大而减小,这是因为壁面附近x负向流动的气流流速绝对值变小,换热削弱;③靶面冲击点附近及冲击靶面后区努塞尔数Nubia随横流的增大而增大,原因是在冲击点上游出现的马蹄涡的旋涡方向和冲击射流自身形成的卷吸涡拉伸涡对方向相同,这两种涡的叠加使该区域冲击靶面的换热得到增强.%Experimental and numerical investigations were made to simulate heat transfer characteristics of a single impinging hole and short impinging distance with cross-flow.The results show that:(1)in the experiment,the average Nusselt number of the impingement surface increases with the increase of cross-flow;(2)the Nusselt number in the front impact area decreases with the increase of cross-flow,because the flow velocity near the wall decreases,weakening the heat transfer effect;(3)the Nusselt number behind impact area near the impact point increases with the increase of cross-flow,because the vortexes directions between the horseshoe vortex in the upstream near the impact point and the stretching vortex produced by impinging jet are the same,and these two vortexes enhance the heat transfer in the impact surface.

  13. Fluorescence Imaging Study of Impinging Underexpanded Jets

    Science.gov (United States)

    Inman, Jennifer A.; Danehy, Paul M.; Nowak, Robert J.; Alderfer, David W.

    2008-01-01

    An experiment was designed to create a simplified simulation of the flow through a hole in the surface of a hypersonic aerospace vehicle and the subsequent impingement of the flow on internal structures. In addition to planar laser-induced fluorescence (PLIF) flow visualization, pressure measurements were recorded on the surface of an impingement target. The PLIF images themselves provide quantitative spatial information about structure of the impinging jets. The images also help in the interpretation of impingement surface pressure profiles by highlighting the flow structures corresponding to distinctive features of these pressure profiles. The shape of the pressure distribution along the impingement surface was found to be double-peaked in cases with a sufficiently high jet-exit-to-ambient pressure ratio so as to have a Mach disk, as well as in cases where a flow feature called a recirculation bubble formed at the impingement surface. The formation of a recirculation bubble was in turn found to depend very sensitively upon the jet-exit-to-ambient pressure ratio. The pressure measured at the surface was typically less than half the nozzle plenum pressure at low jet pressure ratios and decreased with increasing jet pressure ratios. Angled impingement cases showed that impingement at a 60deg angle resulted in up to a factor of three increase in maximum pressure at the plate compared to normal incidence.

  14. Assessment of unsteady-RANS approach against steady-RANS approach for predicting twin impinging jets in a cross-flow

    Directory of Open Access Journals (Sweden)

    Zhiyin Yang

    2014-12-01

    Full Text Available A complex flow field is created when a vertical/short take-off and landing aircraft is operating near ground. One major concern for this kind of aircraft in ground effect is the possibility of ingestion of hot gases from the jet engine exhausts back into the engine, known as hot gas ingestion, which can increase the intake air temperature and also reduce the oxygen content in the intake air, potentially leading to compressor stall, low combustion efficiency and causing a dramatic loss of lift. This flow field can be represented by the configuration of twin impinging jets in a cross-flow. Accurate prediction of this complicated flow field under the Reynolds averaged Navier–Stokes (RANS approach (current practise in industry is a great challenge as previous studies suggest that some important flow features cannot be captured by the Steady-RANS (SRANS approach even with a second-order Reynolds stress model (RSM. This paper presents a numerical study of this flow using the Unsteady-RANS (URANS approach with a RSM and the results clearly indicate that the URANS approach is superior than the SRANS approach but still the predictions of Reynolds stress are not accurate enough.

  15. Low-Gravity Mimicking Simulants and Evaluation of Simulant Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will provide a new method for testing flow/no-flow conditions and other gravity-driven flow behavior of Lunar or planetary regolith under reduced...

  16. Posterior ankle impingement.

    Science.gov (United States)

    Giannini, Sandro; Buda, Roberto; Mosca, Massimiliano; Parma, Alessandro; Di Caprio, Francesco

    2013-03-01

    Posterior ankle impingement is a common cause of chronic ankle pain and results from compression of bony or soft tissue structures during ankle plantar flexion. Bony impingement is most commonly related to an os trigonum or prominent trigonal process. Posteromedial soft tissue impingement generally arises from an inversion injury, with compression of the posterior tibiotalar ligament between the medial malleolus and talus. Posterolateral soft tissue impingement is caused by an accessory ligament, the posterior intermalleolar ligament, which spans the posterior ankle between the posterior tibiofibular and posterior talofibular ligaments. Finally, anomalous muscles have also been described as a cause of posterior impingement.

  17. Axisymmetric rotational stagnation point flow impinging radially a permeable stretching/shrinking surface in a nanofluid using Tiwari and Das model

    Science.gov (United States)

    Roşca, Natalia C.; Pop, Ioan

    2017-01-01

    In this paper, the problem of normal impingement rotational stagnation-point flow on a radially permeable stretching sheet in a viscous fluid, recently studied in a very interesting paper, is extended to a water-based nanofluid. A similarity transformation is used to reduce the system of governing nonlinear partial differential equations to a system of ordinary differential equations, which is then solved numerically using the function bvp4c from Matlab. It is found that dual (upper and lower branch) solutions exist for some values of the governing parameters. From the stability analysis, it is found that the upper branch solution is stable, while the lower branch solution is unstable. Sample velocity and temperature profiles along both solution branches are graphically presented.

  18. Axisymmetric rotational stagnation point flow impinging radially a permeable stretching/shrinking surface in a nanofluid using Tiwari and Das model

    Science.gov (United States)

    Roşca, Natalia C.; Pop, Ioan

    2017-01-01

    In this paper, the problem of normal impingement rotational stagnation-point flow on a radially permeable stretching sheet in a viscous fluid, recently studied in a very interesting paper, is extended to a water-based nanofluid. A similarity transformation is used to reduce the system of governing nonlinear partial differential equations to a system of ordinary differential equations, which is then solved numerically using the function bvp4c from Matlab. It is found that dual (upper and lower branch) solutions exist for some values of the governing parameters. From the stability analysis, it is found that the upper branch solution is stable, while the lower branch solution is unstable. Sample velocity and temperature profiles along both solution branches are graphically presented. PMID:28079124

  19. Impinging Jet Dynamics

    CERN Document Server

    Chen, Xiaodong

    2012-01-01

    In this fluid dynamics video, Ray-tracing data visualization technique was used to obtain realistic and detailed flow motions during impinging of two liquid jets. Different patterns of sheet and rim configurations were presented to shed light into the underlying physics, including liquid chain, closed rim, open rim, unstable rim and flapping sheet. In addition, stationary asymmetrical waves were observed and compared with existing theories. The generation of stationary capillary wave in respect to the liquid rim were explained by the classic shallow water wave theory. The atomization process caused by development of the impact waves were observed in detail, including fragmentation of liquid sheet, formation of liquid ligaments, and breakup of ligament into droplet. The locking-on feature of the wavelength of impact wave were also found to be similar to that of perturbed free shear layers.

  20. Coupled Lagrangian impingement spray model for doublet impinging injectors under liquid rocket engine operating conditions

    Directory of Open Access Journals (Sweden)

    Qiang WEI

    2017-08-01

    Full Text Available To predict the effect of the liquid rocket engine combustion chamber conditions on the impingement spray, the conventional uncoupled spray model for impinging injectors is extended by considering the coupling of the jet impingement process and the ambient gas field. The new coupled model consists of the plain-orifice sub-model, the jet-jet impingement sub-model and the droplet collision sub-model. The parameters of the child droplet are determined with the jet-jet impingement sub-model using correlations about the liquid jet parameters and the chamber conditions. The overall model is benchmarked under various impingement angles, jet momentum and off-center ratios. Agreement with the published experimental data validates the ability of the model to predict the key spray characteristics, such as the mass flux and mixture ratio distributions in quiescent air. Besides, impinging sprays under changing ambient pressure and non-uniform gas flow are investigated to explore the effect of liquid rocket engine chamber conditions. First, a transient impingement spray during engine start-up phase is simulated with prescribed pressure profile. The minimum average droplet diameter is achieved when the orifices work in cavitation state, and is about 30% smaller than the steady single phase state. Second, the effect of non-uniform gas flow produces off-center impingement and the rotated spray fan by 38°. The proposed model suggests more reasonable impingement spray characteristics than the uncoupled one and can be used as the first step in the complex simulation of coupling impingement spray and combustion in liquid rocket engines.

  1. Assessment of subgrid-scale models with a large-eddy simulation-dedicated experimental database: The pulsatile impinging jet in turbulent cross-flow

    Science.gov (United States)

    Baya Toda, Hubert; Cabrit, Olivier; Truffin, Karine; Bruneaux, Gilles; Nicoud, Franck

    2014-07-01

    Large-Eddy Simulation (LES) in complex geometries and industrial applications like piston engines, gas turbines, or aircraft engines requires the use of advanced subgrid-scale (SGS) models able to take into account the main flow features and the turbulence anisotropy. Keeping this goal in mind, this paper reports a LES-dedicated experiment of a pulsatile hot-jet impinging a flat-plate in the presence of a cold turbulent cross-flow. Unlike commonly used academic test cases, this configuration involves different flow features encountered in complex configurations: shear/rotating regions, stagnation point, wall-turbulence, and the propagation of a vortex ring along the wall. This experiment was also designed with the aim to use quantitative and nonintrusive optical diagnostics such as Particle Image Velocimetry, and to easily perform a LES involving a relatively simple geometry and well-controlled boundary conditions. Hence, two eddy-viscosity-based SGS models are investigated: the dynamic Smagorinsky model [M. Germano, U. Piomelli, P. Moin, and W. Cabot, "A dynamic subgrid-scale eddy viscosity model," Phys. Fluids A 3(7), 1760-1765 (1991)] and the σ-model [F. Nicoud, H. B. Toda, O. Cabrit, S. Bose, and J. Lee, "Using singular values to build a subgrid-scale model for large eddy simulations," Phys. Fluids 23(8), 085106 (2011)]. Both models give similar results during the first phase of the experiment. However, it was found that the dynamic Smagorinsky model could not accurately predict the vortex-ring propagation, while the σ-model provides a better agreement with the experimental measurements. Setting aside the implementation of the dynamic procedure (implemented here in its simplest form, i.e., without averaging over homogeneous directions and with clipping of negative values to ensure numerical stability), it is suggested that the mitigated predictions of the dynamic Smagorinsky model are due to the dynamic constant, which strongly depends on the mesh resolution

  2. Experiments on free and impinging supersonic microjets

    Energy Technology Data Exchange (ETDEWEB)

    Phalnikar, K.A.; Kumar, R.; Alvi, F.S. [Florida A and M University and Florida State University, Department of Mechanical Engineering, Tallahassee, FL (United States)

    2008-05-15

    The fluid dynamics of microflows has recently commanded considerable attention because of their potential applications. Until now, with a few exceptions, most of the studies have been limited to low speed flows. This experimental study examines supersonic microjets of 100-1,000 {mu}m in size with exit velocities in the range of 300-500 m/s. Such microjets are presently being used to actively control larger supersonic impinging jets, which occur in STOVL (short takeoff and vertical landing) aircraft, cavity flows, and flow separation. Flow properties of free as well as impinging supersonic microjets have been experimentally investigated over a range of geometric and flow parameters. The flowfield is visualized using a micro-schlieren system with a high magnification. These schlieren images clearly show the characteristic shock cell structure typically observed in larger supersonic jets. Quantitative measurements of the jet decay and spreading rates as well as shock cell spacing are obtained using micro-pitot probe surveys. In general, the mean flow features of free microjets are similar to larger supersonic jets operating at higher Reynolds numbers. However, some differences are also observed, most likely due to pronounced viscous effects associated with jets at these small scales. Limited studies of impinging microjets were also conducted. They reveal that, similar to the behavior of free microjets, the flow structure of impinging microjets strongly resembles that of larger supersonic impinging jets. (orig.)

  3. Experiments on free and impinging supersonic microjets

    Science.gov (United States)

    Phalnikar, K. A.; Kumar, R.; Alvi, F. S.

    2008-05-01

    The fluid dynamics of microflows has recently commanded considerable attention because of their potential applications. Until now, with a few exceptions, most of the studies have been limited to low speed flows. This experimental study examines supersonic microjets of 100-1,000 μm in size with exit velocities in the range of 300-500 m/s. Such microjets are presently being used to actively control larger supersonic impinging jets, which occur in STOVL (short takeoff and vertical landing) aircraft, cavity flows, and flow separation. Flow properties of free as well as impinging supersonic microjets have been experimentally investigated over a range of geometric and flow parameters. The flowfield is visualized using a micro-schlieren system with a high magnification. These schlieren images clearly show the characteristic shock cell structure typically observed in larger supersonic jets. Quantitative measurements of the jet decay and spreading rates as well as shock cell spacing are obtained using micro-pitot probe surveys. In general, the mean flow features of free microjets are similar to larger supersonic jets operating at higher Reynolds numbers. However, some differences are also observed, most likely due to pronounced viscous effects associated with jets at these small scales. Limited studies of impinging microjets were also conducted. They reveal that, similar to the behavior of free microjets, the flow structure of impinging microjets strongly resembles that of larger supersonic impinging jets.

  4. Mimicking of cerebral autoregulation by flow-dependent cerebrovascular resistance: a feasibility study.

    Science.gov (United States)

    Kaufmann, Tim A S; Wong, Kai C; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2012-04-01

    Understanding circulatory autoregulation is essential for improving physiological control of rotary blood pumps and support conditions during cardiopulmonary bypass (CPB). Cerebral autoregulation (CAR), arguably the most critical, is the body's intrinsic ability to maintain sufficient cerebral blood flow (CBF) despite changes in aortic perfusion pressure. It is therefore imperative to include this mechanism into computational fluid dynamics (CFD), particle image velocimetry (PIV), or mock circulation loop (MCL) studies. Without such inclusions, potential losses of CBF are overestimated. In this study, a mathematical model to mimic CAR is implemented in a MCL- and PIV-validated CFD model. A three-dimensional model of the human vascular system was created from magnetic resonance imaging records. Numerical flow simulations were performed for physiological conditions and CPB. The inlet flow was varied between 4.5 and 6 L/min. Arterial outlets were modeled using vessel-specific, flow-dependent cerebrovascular resistances (CVRs), resulting in a variation of the pressure drop between 0 and 80mmHg. CBF is highly dependent on the level of CAR during CPB. By varying the CVR parameters up to the beginning of plateau phase, it can be regulated between 0 and 80% of physiological CBF. So while implementing autoregulation, CBF remains unchanged during a simulated native cardiac output of 5L/min or CPB support of 6L/min. Neglecting CAR, constant backflow from the brain occurs for some cannula positions. Using flow-dependent CVR, CBF returns to its baseline at a rate of recovery of 0.25s. Results demonstrate that modeling of CAR by flow-dependent CVR delivers feasible results. The presented method can be used to optimize physiological control of assist devices dependent upon different levels of CAR representing different patients.

  5. Subacromial impingement syndrome

    NARCIS (Netherlands)

    Umer, M.; Qadir, I.; Azam, M.

    2012-01-01

    Subacromial impingement syndrome (SAIS) represents a spectrum of pathology ranging from subacromial bursitis to rotator cuff tendinopathy and full-thickness rotator cuff tears. The relationship between subacromial impingement and rotator cuff disease in the etiology of rotator cuff injury is a

  6. Subacromial impingement syndrome

    NARCIS (Netherlands)

    Umer, M.; Qadir, I.; Azam, M.

    2012-01-01

    Subacromial impingement syndrome (SAIS) represents a spectrum of pathology ranging from subacromial bursitis to rotator cuff tendinopathy and full-thickness rotator cuff tears. The relationship between subacromial impingement and rotator cuff disease in the etiology of rotator cuff injury is a matte

  7. Ischiofemoral impingement syndrome

    Directory of Open Access Journals (Sweden)

    Cuneyt Tamam

    2015-06-01

    Full Text Available Ischiofemoral impingement is newly recognized extracapsular cause of atypical hip and groin pain. Ischiofemoral impingement was first defined by Johnson in 1977. It is characterized by a narrowed space between the ischial tuberosity and the lesser trochanter, associated with changes in ischiofemoral space . The diagnosis of the ischiofemoral impingement is complex. Normal radiological and ultrasound appearances may be seen in ischiofemoral impingement patients with atypical hip pain. It is important to have a focus on the symptoms , through the history taking, physi and not;cal examination, and appropriate imaging studies of the hip.In this study, we aimed to review the etiology, clinical presentation, imaging modalities, differential diagnosis and treatment options of ischiofemoral impingement. [Archives Medical Review Journal 2015; 24(2.000: 271-281

  8. Flow Cytometry as a Diagnostic Tool in the Early Diagnosis of Aggressive Lymphomas Mimicking Life-Threatening Infection

    Directory of Open Access Journals (Sweden)

    Nikolaos J. Tsagarakis

    2011-01-01

    Full Text Available Aggressive lymphomas can present with symptoms mimicking life-threatening infection. Flow cytometry (FC is usually recommended for the classification and staging of lymphomas in patients with organomegaly and atypical cells in effusions and blood, after the exclusion of other possible diagnoses. FC may also have a place in the initial diagnostic investigation of aggressive lymphoma. Three cases are presented here of highly aggressive lymphomas in young adults, which presented with the clinical picture of fever of unknown origin (FUO in patients severely ill. All followed a life-threatening clinical course, and two developed the hemophagocytic syndrome (HPS, but microbiological, immunological, and morphological evaluation and immunohistochemistry (IHC failed to substantiate an early diagnosis. FC was the technique that provided conclusive diagnostic evidence of lymphoma, subsequently verified by IHC. Our experience with these three cases highlights the potential role of FC as an adjunct methodology in the initial assessment of possible highly aggressive lymphoma presenting with the signs and symptoms of life-threatening infection, although the definitive diagnosis should be established by biopsy. In such cases, FC can contribute to the diagnosis of lymphoma, independently of the presence of HPS.

  9. Cutaneous T cell lymphoma mimicking cutaneous histiocytosis: differentiation by flow cytometry.

    Science.gov (United States)

    Baines, S J; McCormick, D; McInnes, E; Dunn, J K; Dobson, J M; McConnell, I

    2000-07-01

    A two-year-old, neutered female cross-bred labrador had multiple cutaneous nodules, biopsies of which revealed pathological changes consistent with cutaneous histiocytosis. During a period of one month the dog developed multicentric lymphadenopathy, a retrobulbar mass and masses within the quadriceps and cervical muscles. Fine needle aspiration cytology of the cutaneous nodules and lymph nodes and histological examination of the cutaneous nodules and muscle masses suggested the presence of lymphoblastic lymphoma. A definitive diagnosis of CD8+ T cell lymphoma was achieved by immunophenotyping the tumour cells by flow cytometry.

  10. Electrical Aspects of Impinging Flames

    Science.gov (United States)

    Chien, Yu-Chien

    This dissertation examines the use of electric fields as one mechanism for controlling combustion as flames are partially extinguished when impinging on nearby surfaces. Electrical aspects of flames, specifically, the production of chemi-ions in hydrocarbon flames and the use of convective flows driven by these ions, have been investigated in a wide range of applications in prior work but despite this fairly comprehensive effort to study electrical aspects of combustion, relatively little research has focused on electrical phenomena near flame extinguishment, nor for flames near impingement surfaces. Electrical impinging flames have complex properties under global influences of ion-driven winds and flow field disturbances from the impingement surface. Challenges of measurements when an electric field is applied in the system have limited an understanding of changes to the flame behavior and species concentrations caused by the field. This research initially characterizes the ability of high voltage power supplies to respond on sufficiently short time scales to permit real time electrical flame actuation. The study then characterizes the influence of an electric field on the impinging flame shape, ion current and flow field of the thermal plume associated with the flame. The more significant further examinations can be separated into two parts: 1) the potential for using electric fields to control the release of carbon monoxide (CO) from surface-impinging flames, and 2) an investigation of controlling electrically the heat transfer to a plate on which the flame impinges. Carbon monoxide (CO) results from the incomplete oxidation of hydrocarbon fuels and, while CO can be desirable in some syngas processes, it is usually a dangerous emission from forest fires, gas heaters, gas stoves, or furnaces where insufficient oxygen in the core reaction does not fully oxidize the fuel to carbon dioxide and water. Determining how carbon monoxide is released and how heat transfer

  11. Production of all trans-beta-carotene by using impinging flow of supercritical carbon dioxide anti-solvent pulverization.

    Science.gov (United States)

    Shen, Yi-Chen; Chng, Lee-Muei; Wang, Yuan-Chuen; Shieh, Chwen-Jen; Lin, Kuo-Li; Hsu, Shih-Lan; Chou, Hong-Nong; Chang, Chieh-Ming J

    2012-12-28

    This work investigated column elution chromatography coupled with supercritical anti-solvent precipitation to produce carotenoid rich microsized particulates from microalgal Dunaliella salina species. The extract contained carotenoids ranging from 61.3 mg/g(salina) to 72.5 mg/g(salina) using ultrasonic stirred ethyl ether or tetrahydrofuran (THF) extraction. When 10 L of ethyl alcohol was employed to elute the THF extract, purity of trans-β-carotene is 823.6 mg/g with a recovery of 86.2%. It was found that the supercritical anti-solvent of THF solution at 160 bar and 318 K produced powdered particulates with a purity of carotenoids above 90%. Subsequently, a central composite response surface design method was used to design supercritical anti-solvent precipitation of carotenoid-rich THF solution. This was accomplished by increasing the pressure from 140 bar to 180 bar and the time from 40 min to 60 min at a feed flow rate of 0.2 mL/min. A CO(2) flow rate of 15 L/min and a temperature of 318 K were also used to determine the effects on purity and recovery of trans-β-carotene. The combined process produced micronized precipitates with a mean particle size ranging from 3.5 μm to 19 μm and the purity of trans-β-carotene attained was 926.8 mg/g with a recovery of 54%.

  12. Magnetic Resonance Velocimetry analysis of an angled impinging jet

    Science.gov (United States)

    Irhoud, Alexandre; Benson, Michael; Verhulst, Claire; van Poppel, Bret; Elkins, Chris; Helmer, David

    2016-11-01

    Impinging jets are used to achieve high heat transfer rates in applications ranging from gas turbine engines to electronics. Despite the importance and relative simplicity of the geometry, simulations historically fail to accurately predict the flow behavior in the vicinity of the flow impingement. In this work, we present results from a novel experimental technique, Magnetic Resonance Velocimetry (MRV), which measures three-dimensional time-averaged velocity without the need for optical access. The geometry considered in this study is a circular jet angled at 45 degrees and impinging on a flat plate, with a separation of approximately seven jet diameters between the jet exit and the impingement location. Two flow conditions are considered, with Reynolds numbers of roughly 800 and 14,000. Measurements from the MRV experiment are compared to predictions from Reynolds Averaged Navier Stokes (RANS) simulations, thus demonstrating the utility of MRV for validation of numerical analyses of impinging jet flow.

  13. Lupus mimickers.

    Science.gov (United States)

    Calixto, Omar-Javier; Franco, Juan-Sebastian; Anaya, Juan-Manuel

    2014-08-01

    Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multisystem organ involvement, heterogeneity of clinical features, and variety in degree of severity. The differential diagnosis is a crucial aspect in SLE as many other autoimmune diseases portray clinical similarities and autoantibody positivity. Lupus mimickers refer to a group of conditions that exhibit both clinical features and laboratory characteristics, including autoantibody profiles that resemble those present in patients with SLE, and prompt a diagnostic challenge in everyday clinical practice. Thus, lupus mimickers may present as a lupus-like condition (i.e., 2 or 3 criteria) or as one meeting the classification criteria for SLE. Herein we review and classify the current literature on lupus mimickers based on diverse etiologies which include infections, malign and benign neoplasms, medications, and vaccine-related reactions.

  14. 具有冲击平板的雾化喷雾流中汽液流动的模拟%Simulation of Droplet-gas Flow in the Effervescent Atomization Spray with an Impinging Plate

    Institute of Scientific and Technical Information of China (English)

    钱丽娟; 林建忠; 熊红兵

    2009-01-01

    A comprehensive three-dimensional model of droplet-gas flow was presented to study the evolution of spray in the effervescent atomization spray with an impinging plate. For gas phase, the N-S equation with the κ-ε turbulence model was solved, considering two-way coupling interaction between droplets and gas phase. Dispersed droplet phase is modeled as Lagrangian entities, accounting for the physics of droplet generation from primary and secondary breakup, droplet collision and coalescence, droplet momentum and heat transfer. The mean size and sta-tistical distribution of atomized droplets at various nozzle-to-plate distances were calculated. Some simulation re-sults were compared well with experimental data. The results show that the existence of the impinging plate has a pronounced influence on the droplet mean size, size distribution and the droplet spatial distribution. The air-to-liquid ratio has obvious effects on the droplet size and distribution.

  15. SUBMERGED IMPINGING JETS WITHIN A FINITE WATER DEPTH

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By use of the sheet of laser light and the trac-ing particle technology, flow visualization tests of complexflow structures for submerged impinging jets within finite wa-ter depths are conducted. Typical flow patterns of submergeimpinging jets are analysed by the singular topology method.In order to reveal the mechanism of these flows, the diffusivecharacteristics and turbulent fluctuations of submerged impin-ging jets are measured by the hot-film anemometer.

  16. Subacromial impingement syndrome

    Directory of Open Access Journals (Sweden)

    Masood Umer

    2012-05-01

    Full Text Available Subacromial impingement syndrome (SAIS represents a spectrum of pathology ranging from subacromial bursitis to rotator cuff tendinopathy and full-thickness rotator cuff tears. The relationship between subacromial impingement and rotator cuff disease in the etiology of rotator cuff injury is a matter of debate. However the etiology is multi-factorial, and has been attributed to both extrinsic and intrinsic mechanisms. Management includes physical therapy, injections, and, for some patients, surgery. No high-quality RCTs are available so far to provide possible evidence for differences in outcome of different treatment strategies. There remains a need for high-quality clinical research on the diagnosis and treatment of SAIS.

  17. Spray formation processes of impinging jet injectors

    Science.gov (United States)

    Anderson, W. E.; Ryan, H. M.; Pal, S.; Santoro, R. J.

    1993-11-01

    A study examining impinging liquid jets has been underway to determine physical mechanisms responsible for combustion instabilities in liquid bi-propellant rocket engines. Primary atomization has been identified as an important process. Measurements of atomization length, wave structure, and drop size and velocity distribution were made under various ambient conditions. Test parameters included geometric effects and flow effects. It was observed that pre-impingement jet conditions, specifically whether they were laminar or turbulent, had the major effect on primary atomization. Comparison of the measurements with results from a two dimensional linear aerodynamic stability model of a thinning, viscous sheet were made. Measured turbulent impinging jet characteristics were contrary to model predictions; the structure of waves generated near the point of jet impingement were dependent primarily on jet diameter and independent of jet velocity. It has been postulated that these impact waves are related to pressure and momentum fluctuations near the impingement region and control the eventual disintegration of the liquid sheet into ligaments. Examination of the temporal characteristics of primary atomization (ligament shedding frequency) strongly suggests that the periodic nature of primary atomization is a key process in combustion instability.

  18. Microtextured Surfaces for Turbine Blade Impingement Cooling

    Science.gov (United States)

    Fryer, Jack

    2014-01-01

    Gas turbine engine technology is constantly challenged to operate at higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can exceed the blade and disk material limits by 600 F or more, necessitating both internal and film cooling schemes in addition to the use of thermal barrier coatings. Internal convective cooling is inadequate in many blade locations, and both internal and film cooling approaches can lead to significant performance penalties in the engine. Micro Cooling Concepts, Inc., has developed a turbine blade cooling concept that provides enhanced internal impingement cooling effectiveness via the use of microstructured impingement surfaces. These surfaces significantly increase the cooling capability of the impinging flow, as compared to a conventional untextured surface. This approach can be combined with microchannel cooling and external film cooling to tailor the cooling capability per the external heating profile. The cooling system then can be optimized to minimize impact on engine performance.

  19. Femoroacetabular impingement surgery

    DEFF Research Database (Denmark)

    Reiman, Michael P; Thorborg, Kristian

    2015-01-01

    Femoroacetabuler impingement (FAI) is becoming increasingly recognised as a potential pathological entity for individuals with hip pain. Surgery described to correct FAI has risen exponentially in the past 10 years with the use of hip arthroscopy. Unfortunately, the strength of evidence supporting...

  20. Nanofluid impingement jet heat transfer.

    Science.gov (United States)

    Zeitoun, Obida; Ali, Mohamed

    2012-02-17

    Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters.

  1. Numerical Simulation of Three Dimensional Flow Field of Vertical Circulative Impinging Stream Reactor%立式循环撞击流反应器三维流场的数值模拟

    Institute of Scientific and Technical Information of China (English)

    杨侠; 罗燕; 郭嘉; 张捷; 吴艳阳

    2011-01-01

    The three-dimensional flow field of vertical circulative impinging stream reactor was simulated. The results show that the velocity and pressure distribution in it are symmetrical to the impinging plane and stagnation surface, and prove the existence of dead bands on right and left sides of the draft tube and in the impinging zone; because of the guiding of the draft tube, the max. velocity in x-axis of impinging zone can appear near the wall of the draft tube, and the dimensional coefficient K defined as the mixing efficiency at the initial velocity of different impinging streams can change with the increase of the initial velocity( u0 ), and of which,K fluctuates lightly while the initial velocity ranges between 0.1 and 0.3m/s and increases smoothly while the initial velocity exceeds 0.3m/s.%利用Fluent软件对立式循环撞击流反应器三堆流场进行数值模拟和分析.立式循环撞击流反应器内速度场和压力场分布关于撞击面对称,证实了驻面的存在,导流筒外侧和撞击面边缘存在死区;由于导流筒对流体引导作用,撞击区水平面x轴上速度最大的点出现在导流筒近壁面位置;定义了表征不同撞击流初始速度下混合效率无量纲系数k,且k值随撞击流初始速度μo增加而增大,其中在0.1-0.3m/s之间有小幅波动.大于0.3m/s后增幅平稳.

  2. Numerical Investigation of the Flow Dynamics and Evaporative Cooling of Water Droplets Impinging onto Heated Surfaces: An Effective Approach To Identify Spray Cooling Mechanisms.

    Science.gov (United States)

    Chen, Jian-Nan; Zhang, Zhen; Xu, Rui-Na; Ouyang, Xiao-Long; Jiang, Pei-Xue

    2016-09-13

    Numerical investigations of the dynamics and evaporative cooling of water droplets impinging onto heated surfaces can be used to identify spray cooling mechanisms. Droplet impingement dynamics and evaporation are simulated using the presented numerical model. Volume-of-fluid method is used in the model to track the free surface. The contact line dynamics was predicted from a dynamic contact angle model with the evaporation rate predicted by a kinetic theory model. A species transport equation was solved in the gas phase to describe the vapor convection and diffusion. The numerical model was validated by experimental data. The physical effects including the contact angle hysteresis and the thermocapillary effect are analyzed to offer guidance for future numerical models of droplet impingement cooling. The effects of various parameters including surface wettability, surface temperature, droplet velocity, droplet size, and droplet temperature were numerically studied from the standpoint of spray cooling. The numerical simulations offer profound analysis and deep insight into the spray cooling heat transfer mechanisms.

  3. Numerical simulation of circular jet impinging on hot steel plate

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Flow structure and heat transfer characteristics of an axisymmetric circular jet impinging on a hot 1Cr18Ni9Ti medium plate have been simulated numerically using computational fluid dynamic (CFD) code. The relation between flow field of jet impingement and its heat transfer capability is analyzed, and the phenomenon that heat transfer at stagnation point is smaller than that of points directly around is discussed. The simulation result provides boundary conditions for thermalanalysis of medium plate quenching.

  4. The effect of sediment mimicking drill cuttings on deep water rhodoliths in a flow-through system: Experimental work and modeling.

    Science.gov (United States)

    Figueiredo, Marcia A O; Eide, Ingvar; Reynier, Marcia; Villas-Bôas, Alexandre B; Tâmega, Frederico T S; Ferreira, Carlos Gustavo; Nilssen, Ingunn; Coutinho, Ricardo; Johnsen, Ståle

    2015-06-15

    The impact of sediment coverage on two rhodolith-forming calcareous algae species collected at 100m water depth off the coast of Brazil was studied in an experimental flow-through system. Natural sediment mimicking drill cuttings with respect to size distribution was used. Sediment coverage and photosynthetic efficiency (maximum quantum yield of charge separation in photosystem II, ϕPSIImax) were measured as functions of light intensity, flow rate and added amount of sediment once a week for nine weeks. Statistical experimental design and multivariate data analysis provided statistically significant regression models which subsequently were used to establish exposure-response relationship for photosynthetic efficiency as function of sediment coverage. For example, at 70% sediment coverage the photosynthetic efficiency was reduced 50% after 1-2weeks of exposure, most likely due to reduced gas exchange. The exposure-response relationship can be used to establish threshold levels and impact categories for environmental monitoring.

  5. Femoroacetabular impingement syndrome

    Directory of Open Access Journals (Sweden)

    Tolga Ege

    2016-03-01

    Full Text Available Femoroacetabular impingement (FAI syndrome is a recently understood hip condition that describes the pathologic contact between the femoral neck and the acetabular rim. Previously, it was also called and ldquo;acetabular rim syndrome and rdquo; or and ldquo;cervicoacetabular impingement syndrome and rdquo;. It is characterized by a developmental disorder affecting the femoral neck, acetabular rim and labrum. The chronic irritation on the hip joint causes chondral damage and mechanical changes, and these degenerative changes eventually lead to osteoarthritis. Two types of FAI have been described: Cam type and pincer type. Treatment options for FAI are conservative, open, mini open and arthroscopic surgery. [Arch Clin Exp Surg 2016; 5(1.000: 42-47

  6. Experimental and Computational Study of Underexpanded Jet Impingement Heat Transfer

    Science.gov (United States)

    Rufer, Shann J.; Nowak, Robert J.; Daryabeigi, Kamran; Picetti, Donald

    2009-01-01

    An experiment was performed to assess CFD modeling of a hypersonic-vehicle breach, boundary-layer flow ingestion and internal surface impingement. Tests were conducted in the NASA Langley Research Center 31-Inch Mach 10 Tunnel. Four simulated breaches were tested and impingement heat flux data was obtained for each case using both phosphor thermography and thin film gages on targets placed inside the model. A separate target was used to measure the surface pressure distribution. The measured jet impingement width and peak location are in good agreement with CFD analysis.

  7. Impinging Jet Resonant Modes at Mach 1.5

    CERN Document Server

    Davis, Timothy

    2013-01-01

    High speed impinging jets have been the focus of several studies owing to their practical application and resonance dominated flow-field. The current study focuses on the identification and visualization of the resonant modes at certain critical impingement heights for a Mach 1.5 normally impinging jet. These modes are associated with high amplitude, discrete peaks in the power spectra and can be identified as having either axisymmetric or azimuthal modes. Their visualization is accomplished through phase-locked Schlieren imaging and fast-response pressure sensitive paint (PC-PSP) applied to the ground plane.

  8. Terrestrial Plume Impingement Testbed Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Masten Space Systems proposes to create a terrestrial plume impingement testbed for generating novel datasets for extraterrestrial robotic missions. This testbed...

  9. Circular and Elliptic Submerged Impinging Water Jets

    Science.gov (United States)

    Claudey, Eric; Benedicto, Olivier; Ravier, Emmanuel; Gutmark, Ephraim

    1999-11-01

    Experiments and CFD have been performed to study circular and elliptic jets in a submerged water jet facility. The tests included discharge coefficient measurement to evaluate pressure losses encountered in noncircular nozzles compared to circular ones. Three-dimensional pressure mappings on the impingement surface and PIV measurement of the jet mean and turbulent velocity have been performed at different compound impingement angles relative to the impingement surface and at different stand-off distances. The objective was to investigate the effect of the non-circular geometry on the flow field and on the impact region. The tests were performed in a close loop system in which the water was pumped through the nozzles into a clear Plexiglas tank. The Reynolds numbers were typically in the range of 250000. Discharge coefficients of the elliptic nozzle was somewhat lower than that of the circular jet but spreading rate and turbulence level were higher. Pressure mapping showed that the nozzle exit geometry had an effect on the pressure distribution in the impact region and that high-pressure zones were generated at specific impact points. PIV measurements showed that for a same total exit area, the elliptic jets affected a surface area that is 8the equivalent circular. The turbulence level in the elliptic jet tripled due to the nozzle design. Results of the CFD model were in good agreement with the experimental data.

  10. Flash flow pyrolysis: mimicking flash vacuum pyrolysis in a high-temperature/high-pressure liquid-phase microreactor environment.

    Science.gov (United States)

    Cantillo, David; Sheibani, Hassan; Kappe, C Oliver

    2012-03-02

    Flash vacuum pyrolysis (FVP) is a gas-phase continuous-flow technique where a substrate is sublimed through a hot quartz tube under high vacuum at temperatures of 400-1100 °C. Thermal activation occurs mainly by molecule-wall collisions with contact times in the region of milliseconds. As a preparative method, FVP is used mainly to induce intramolecular high-temperature transformations leading to products that cannot easily be obtained by other methods. It is demonstrated herein that liquid-phase high-temperature/high-pressure (high-T/p) microreactor conditions (160-350 °C, 90-180 bar) employing near- or supercritical fluids as reaction media can mimic the results obtained using preparative gas-phase FVP protocols. The high-T/p liquid-phase "flash flow pyrolysis" (FFP) technique was applied to the thermolysis of Meldrum's acid derivatives, pyrrole-2,3-diones, and pyrrole-2-carboxylic esters, producing the expected target heterocycles in high yields with residence times between 10 s and 10 min. The exact control over flow rate (and thus residence time) using the liquid-phase FFP method allows a tuning of reaction selectivities not easily achievable using FVP. Since the solution-phase FFP method does not require the substrate to be volatile any more--a major limitation in classical FVP--the transformations become readily scalable, allowing higher productivities and space-time yields compared with gas-phase protocols. Differential scanning calorimetry measurements and extensive DFT calculations provided essential information on pyrolysis energy barriers and the involved reaction mechanisms. A correlation between computed activation energies and experimental gas-phase FVP (molecule-wall collisions) and liquid-phase FFP (molecule-molecule collisions) pyrolysis temperatures was derived.

  11. Thermal-hydraulic performance of convective boiling jet array impingement

    Science.gov (United States)

    Jenkins, R.; De Brún, C.; Kempers, R.; Lupoi, R.; Robinson, A. J.

    2016-09-01

    Jet impingement boiling is investigated with regard to heat transfer and pressure drop performance using a novel laser sintered 3D printed jet impingement manifold design. Water was the working fluid at atmospheric pressure with inlet subcooling of 7oC. The convective boiling performance of the impinging jet system was investigated for a flat copper target surface for 2700≤Re≤5400. The results indicate that the heat transfer performance of the impinging jet is independent of Reynolds number for fully developed boiling. Also, the investigation of nozzle to plate spacing shows that low spacing delays the onset of nucleate boiling causing a superheat overshoot that is not observed with larger gaps. However, no sensitivity to the gap spacing was measured once boiling was fully developed. The assessment of the pressure drop performance showed that the design effectively transfers heat with low pumping power requirements. In particular, owing to the insensitivity of the heat transfer to flow rate during fully developed boiling, the coefficient of performance of jet impingement boiling in the fully developed boiling regime deteriorates with increased flow rate due to the increase in pumping power flux.

  12. Hip labral cyst caused by psoas impingement.

    Science.gov (United States)

    Tey, Marc; Alvarez, Sonia; Ríos, Jose L

    2012-08-01

    Hip labral impingement can cause labral tears and secondary paralabral cyst formation. Femoroacetabular impingement is the main cause of labral impingement, but other conditions such as iliopsoas tendon impingement are described. There is no description of labral cyst resulting from psoas impingement treated arthroscopically in the literature. We present the case of a young sportsman with groin pain caused by psoas impingement with a labral tear and secondary paralabral cyst who was treated arthroscopically by cyst debridement, psoas tenotomy, and labral repair. Copyright © 2012 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  13. Cold plate with combined inclined impingement and ribbed channels

    Energy Technology Data Exchange (ETDEWEB)

    Parida, Pritish R.

    2015-12-22

    Heat transfer devices and methods for making the same that include a first enclosure having at least one inlet port; a second enclosure having a bottom plate and one or more dividing walls to establish channels, at least one internal surface of each channel having rib structures to create turbulence in a fluid flow; and a jet plate connecting the first enclosure and the second enclosure having impinging jets that convey fluid from the first enclosure to the channels, said impinging jets being set at an angular deviation from normal to cause local acceleration of fluid and to increase a local heat transfer rate.

  14. The effect of liquid film on liquid droplet impingement erosion

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Nobuyuki, E-mail: fujisawa@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Yamagata, Takayuki, E-mail: yamagata@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Saito, Kengo; Hayashi, Kanto [Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan)

    2013-12-15

    Highlights: • Liquid droplet impingement erosion is studied experimentally using high-speed conical spray. • Erosion rate is increased with decreasing the liquid film thickness. • Erosion model is proposed considering the influence of liquid film thickness. -- Abstract: In the present paper, the pipe-wall thinning due to liquid droplet impingement erosion is studied experimentally by using a high-speed conical spray under the influences of liquid film on the target specimen. The size of the droplets considered is an order of tens of micrometers in diameter, which is the same order as those expected in the pipeline of nuclear/fossil power plants. In order to evaluate the erosion rate by the liquid droplet impingement under the influence of liquid film, the experiments are conducted by various combinations of the specimen diameters and the standoff distances of the spray from the nozzle. The experimental results show that the erosion depth increases linearly with the local flow volume, indicating the presence of terminal stage of erosion. The present results indicate that the erosion rate increases with decreasing the specimen diameter and increases slightly with increasing the standoff distance. This result combined with the theoretical consideration of the liquid film on the specimen leads to the conclusion that the erosion rate increases with decreasing the liquid film thickness, which supports the numerical result of liquid droplet impingement erosion in literature. Then, the erosion model for predicting the erosion rate by the liquid droplet impingement is proposed considering the influence of the liquid film.

  15. Effects of chemical reaction and partial slip on the three-dimensional flow of a nanofluid impinging on an exponentially stretching surface

    Science.gov (United States)

    Mahanthesh, B.; Mabood, F.; Gireesha, B. J.; Gorla, R. S. R.

    2017-03-01

    The three-dimensional mixed convection boundary layer flow of a nanofluid induced by an exponentially stretching sheet is numerically investigated in the presence of thermal radiation, heat source/sink and first-order chemical reaction effects. The adopted nanofluid model incorporates the effects of Brownian motion and thermophoresis into the mathematical model. The first-order velocity slip boundary conditions are also taken into account. The governing boundary layer equations are transformed into a set of nonlinear ordinary differential equations by employing suitable similarity variables. The resultant equations are solved numerically using the Runge-Kutta-Fehlberg method. Obtained solutions are compared with previous results in a limiting sense from the literature, demonstrating an excellent agreement. To show the typical trend of the solutions, a parametric study is conducted. The axial velocity, transverse velocity, temperature and nanoparticle volume fraction profiles as well as the skin-friction coefficient, Nusselt and Sherwood numbers are demonstrated graphically as a representative set of numerical results and discussed comprehensively.

  16. A Single Parameter to Characterize Wall Shear Stress Developed from an Underexpanded Axisymmetric Impinging Jet

    Science.gov (United States)

    Fillingham, Patrick; Murali, Harikrishnan

    2016-11-01

    Wall shear stress is characterized for underexpanded axisymmetric impinging jets for the application of aerodynamic particle resuspension from a surface. Analysis of the flow field and the wall shear stress resulted from normally impinging axisymmetric jets is conducted using Computational Fluid Dynamics. A normally impinging jet is modeled with a constant area nozzle, while varying height to diameter ratio (H/D) and inlet pressures. Schlieren photography is used to visualize the density gradient of the flow field for validation of the CFD. The Dimensionless Jet Parameter (DJP) is developed to describe flow regimes and characterize the shear stress. The DJP is defined as being proportional to the jet pressure ratio divided by the H/D ratio squared. Maximum wall shear stress is examined as a function of DJP with three distinct regimes: (i) subsonic impingement (DJP2). Due to the jet energy dissipation in shock structures, which become a dominant dissipation mechanism in the supersonic impingement regime, wall shear stress is limited to a finite value. Additionally, formation of shock structures in the wall flow were observed for DJP>2 resulting in difficulties with dimensionless analysis. In the subsonic impingement and transitional regimes equations as a function of the DJP are obtained for the maximum wall shear stress magnitude, maximum shear stress location, and shear stress decay. Using these relationships wall shear stress can be predicted at all locations along the impingement surface.

  17. Sessile drop deformations under an impinging jet

    Science.gov (United States)

    Feng, James Q.

    2015-08-01

    The problem of steady axisymmetric deformations of a liquid sessile drop on a flat solid surface under an impinging gas jet is of interest for understanding the fundamental behavior of free surface flows as well as for establishing the theoretical basis in process design for the Aerosol direct-write technology. It is studied here numerically using a Galerkin finite-element method, by computing solutions of Navier-Stokes equations. For effective material deposition in Aerosol printing, the desired value of Reynolds number for the laminar gas jet is found to be greater than ~500. The sessile drop can be severely deformed by an impinging gas jet when the capillary number is approaching a critical value beyond which no steady axisymmetric free surface deformation can exist. Solution branches in a parameter space show turning points at the critical values of capillary number, which typically indicate the onset of free surface shape instability. By tracking solution branches around turning points with an arc-length continuation algorithm, critical values of capillary number can be accurately determined. Near turning points, all the free surface profiles in various parameter settings take a common shape with a dimple at the center and bulge near the contact line. An empirical formula for the critical capillary number for sessile drops with contact angle is derived for typical ranges of jet Reynolds number and relative drop sizes especially pertinent to Aerosol printing.

  18. Modeling 2-D jets impinging on Stirling regenerators

    Science.gov (United States)

    Gedeon, David

    1989-01-01

    The extent to which flow leaving Stirling coolers or heaters in the form of high-velocity jets penetrate the regenerator matrix is visually modeled using a computer program. Two-dimensional laminar jets are shown impinging on regenerator samples of variable permeability ranging from no matrix at all to matrices dense enough to stop the jet dead on. The results lend credibility to a simple tension for flow uniformity as a function of penetration depth.

  19. Liquid jet impinging orthogonally on a wettability-patterned surface

    Science.gov (United States)

    Koukoravas, Theodore; Ghosh, Aritra; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Megaridis, Constantine

    2016-11-01

    Jet impingement has many technological applications because of its numerous merits, especially those related to the ability of liquids to carry away heat very efficiently. The present study introduces a new configuration employing a wettability-patterning approach to divert an orthogonally-impinging laminar water jet onto a predetermined portion of the target surface. Diverging wettable tracks on a superhydrophobic background provide the means to re-direct the impinging jet along paths determined by the shape of these tracks on the solid surface. In a heat transfer example of this method, an open-surface heat exchanger is constructed and its heat transfer performance is characterized. Since this approach facilitates prolonged liquid contact with the underlying heated surface through thin-film spreading, evaporative cooling is also promoted. We demonstrate flow cases extracting 100 W/cm2 at water flow rates of O(10 mL/min). By comparing with other jet-impingement cooling approaches, the present method provides roughly four times more efficient cooling by using less amount of coolant. The reduced coolant use, combined with the gravity-independent character of this technique, offer a new paradigm for compact heat transfer devices designed to operate in reduced- or zero-gravity environments.

  20. Experimental and Theoretical Analysis of the Impinging Stream Drying

    Institute of Scientific and Technical Information of China (English)

    淮秀兰; SHIGERU; Koyama; 等

    2003-01-01

    The experiments of one-stage semi-circular and two-stage semi-circular impinging stream drying as well as the vertical and semi-cricular combined impinging stream drying were carried out.The velocity distribution and the mean residence time of particles,and the influence of various factors on drying characteristics were studied.A mathematical model of granular material drying in a semi-circular impinging stream dryer was proposed,in which the flow characteristics as well as the heat and mass transfer mechanisms were considered.Reasonable numerical methods were used to solve the equations.Under various conditons,the calculated results of drying rate and moisture content versus time were obtained.The results indicate that constant drying rate period does not exist in a semi-circular impinging stream dryer.Appropriate semi-cricular stage number and curvature radius,flow-rate ratio,air velocity,and higher inlet air temperature should be used for enhancing the drying process.

  1. [Athletic pubalgia and hip impingement].

    Science.gov (United States)

    Berthaudin, A; Schindler, M; Ziltener, J-L; Menetrey, J

    2014-07-16

    Athletic pubalgia is a painful and complex syndrom encountered by athletes involved in pivoting and cutting sports such as hockey and soccer. To date, there is no real consensus on the criteria for a reliable diagnostic, the different investigations, and the appropriate therapy. Current literature underlines intrinsic and extrinsic factors contributing to athletic pubalgia. This review article reports upon two novelties related to the issue: the importance and efficience of prevention program and the association of femoro-acetabular impingement with the pubalgia.

  2. Numerical Investigation on Jet Impingement Behaviors Affected by a Vertically Rotating Disk Suspended Close to the Surface

    Directory of Open Access Journals (Sweden)

    Liu Bo

    2014-01-01

    Full Text Available A simplified physical model is built up to study the swirl flow effect induced by a rotating disk on the jet impingement behaviors, which is adopted to simulate the grinding process. To solve the definition problem of the interface between a rotating disk and a stationary plate in the computational simulation, a tiny gap is set between the rotating disk and the stationary plate. The results show that the rotating disk suspended above the surface adds more complexity to the flow field of jet impingement on a stationary plate. The swirling flow around the rotating disk obstructs the impinging jet flow to penetrate into the interfacial contact zone and forces the wall jet across the rotating disk to flow along transverse directions. For the given jet impinging velocity and nozzle orientation, as the disk rotational speed increases, the effect of the rotating disk on the impinging jet flow behaves more significantly. The impinging jet with small inject velocity is difficult to penetrate through the interfacial contact zone to follow by the disk swirl flows. For smaller jet impinging distance or larger oblique angle, the flow recirculation away from the interfacial contact zone becomes stronger.

  3. Measurements of a single pulse impinging jet. A CFD reference

    Directory of Open Access Journals (Sweden)

    Bovo Mirko

    2014-03-01

    Full Text Available This paper reports three sets of measurements of a single pulse impinging jet. The purpose is to serve as a reference for CFD validation. A gas injector generates a single pulse jet at Re ~90000. The jet impinges on a temperature controlled flat target at different angles (0º, 30º, 45º and 60º. The jet velocity field is measured with PIV. The evolution of the jet velocity profile in time is reported at two different locations (suitable as CFD inlet conditions. At the same locations also turbulence quantities are reported. The impingement wall temperature is measured with fast responding thermocouples and infrared camera. These give high time and space resolution respectively. Results are reported in a format suitable for comparison with CFD simulations. The results show that the heat transfer effects are highest for the jet impinging normally on the target. Target inclination has remarkable effects on the jet penetration rate and repeatability. Even small target inclinations result creates a preferential direction for the jet flow and cause a shift in the position of the stagnation region.

  4. Conjugate heat transfer study of a turbulent slot jet impinging on a moving plate

    Science.gov (United States)

    Achari, A. Madhusudana; Das, Manab Kumar

    2017-03-01

    Numerical simulation of the flow field and conjugate heat transfer in an impinging jet with moving impingement plate is one of the important problems as it mimics closely with practical applications in industries. The Yang-Shih version of low Reynolds number k-ɛ model has been used to resolve the flow field and the temperature field in a two-dimensional, steady, incompressible, confined, turbulent slot jet impinging normally on a moving flat plate of finite thickness. The turbulence intensity and the Reynolds number considered at the inlet are 2 % and 15,000, respectively. The bottom face of the impingement plate has been maintained at a constant temperature higher than the nozzle exit temperature. The confinement plate has been considered to be adiabatic. The nozzle-to-surface spacing for the above study has been taken to be 6 and the surface-to-jet velocity ratios have been taken over a range of 0.25-1. The effects of impingement plate motion on the flow field and temperature field have been discussed elaborately with reference to stationary impingement plate. The dependence of flow field and fluid temperature field on impingement plate motion has been analyzed by plotting streamlines, isotherms for different plate speeds. A thorough study of flow characteristics for different surface-to-jet velocity ratios has been carried out by plotting profiles of mean vertical and horizontal components of velocity, pressure distribution, local shear stress distribution. The isotherms in the impingement plate of finite thickness, the distributions of solid-fluid interface temperature, the local Nusselt number, and the local heat flux for different surface-to-jet velocity ratios added to the understanding of conjugate heat transfer phenomenon.

  5. Particle streak velocimetry and its application to impinging laminar jets

    Science.gov (United States)

    Bergthorson, Jeff; Dimotakis, Paul

    2002-11-01

    The technique of Particle Streak Velocimetry (PSV) was improved to include digital imaging and image processing, allowing it to compete with PIV or LDV in terms of accuracy and ease of implementation. PSV provides advantages over other techniques, such as low particle mass loading, short run time experiments, and high accuracy velocity data through the direct measurement of Lagrangian trajectories. PSV, coupled with measurements of the static (Bernoulli) pressure drop across a well designed nozzle contraction, provided redundancy in the measurement of the axisymmetric impinging laminar jet. The impinging laminar jet was studied in the intermediate regime where the existence of a stagnation plate will affect the flow out of the nozzle. This nozzle separation to diameter ratio, L/d_j, regime has not been well characterized. The results indicate that a one-dimensional streamfunction formulation is not sufficient to characterize this flow.

  6. Radial heat transfer behavior of impinging submerged circular jets

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, D.W.; Ma, C.F. [Enhanced Heat Transfer and Energy Conservation, The Key Laboratory of Ministry of Education (China)

    2006-05-15

    Experiments were performed to investigate the radial heat transfer behaviors of impinging submerged circular jets. Local heat transfer rate at several fixed radial locations and different nozzle-to-plate spacings were correlated and compared. Results reveal that with the jet being far from the stagnation point, the coefficient in the correlation NuRe decreases while the exponent characterizing the flow pattern of the working liquid increases. (author)

  7. Turbulent Impinging Jets into Porous Materials

    CERN Document Server

    de Lemos, Marcelo J S

    2012-01-01

    This short book deals with the mathematical modeling of jets impinging porous media. It starts with a short introduction to models describing turbulences in porous media as well as turbulent heat transfer. In its main part, the book presents the heat transfer of impinging jets using a local and a non-local thermal equilibrium approach.

  8. Impingement jet cooling in gas turbines

    CERN Document Server

    Amano, R S

    2014-01-01

    Due to the requirement for enhanced cooling technologies on modern gas turbine engines, advanced research and development has had to take place in field of thermal engineering. Impingement jet cooling is one of the most effective in terms of cooling, manufacturability and cost. This is the first to book to focus on impingement cooling alone.

  9. Thermal chip fabrication with arrays of sensors and heaters for micro-scale impingement cooling heat transfer analysis and measurements.

    Science.gov (United States)

    Shen, C H; Gau, C

    2004-07-30

    The design and fabrication for a thermal chip with an array of temperature sensors and heaters for study of micro-jet impingement cooling heat transfer process are presented. This thermal chip can minimize the heat loss from the system to the ambient and provide a uniform heat flux along the wall, thus local heat transfer processes along the wall can be measured and obtained. The fabrication procedure presented can reach a chip yield of 100%, and every one of the sensors and heaters on the chip is in good condition. In addition, micro-jet impingement cooling experiments are performed to obtain the micro-scale local heat transfer Nusselt number along the wall. Flow visualization for the micro-impinging jet is also made. The experimental results indicate that both the micro-scale impinging jet flow structure and the heat transfer process along the wall is significantly different from the case of large-scale jet impingement cooling process.

  10. Development of modern flow measuring technique applied to fluid characteristic research in impinging stream mixer%现代流动测量技术用于撞击流混合器内流动特性的研究进展

    Institute of Scientific and Technical Information of China (English)

    张建伟; 马彦东; 冯颖

    2012-01-01

    分别介绍了几种现代典型的流动测量技术包括热线风速仪(HWA)、激光多普勒测速技术(LDV)、相位激光多普勒技术(PDA)、激光粒子图像测速技术(PIV)及平面激光诱导荧光技术(PLIF)的基本工作原理。在对这些技术在近几年的应用状况进行了介绍和分析,指出使用这些测量技术对撞击流混合器内流场进行测试的重要意义。同时介绍了一种新型撞击流装置,并对撞击流的进一步研究进行展望。%In this article,several typical modern flow measure techniques are introduced separately,which include hot wire Anemometry(HWA),Laser Doppler Anemometry(LDA),Phase Doppler Anemometry(PDA),Particle Image Velocimetry(PIV) and Plane Laser Induced Fluorescence(PLIF).Based on the introduction and analysis of the interior application status of these techniques,the importance of applying these techniques to measuring flow characteristic in impinging mixer are addressed.A new impinging stream device is also introduced,and the further study on the impinging stream is prospected.

  11. [Clinical or radiological diagnosis of impingement].

    Science.gov (United States)

    Kloth, J K; Zeifang, F; Weber, M-A

    2015-03-01

    Shoulder impingement syndrome is a clinically common entity involving trapping of tendons or bursa with typical clinical findings. Important radiological procedures are ultrasound, magnetic resonance imaging (MRI) and MR arthrography. Projection radiography and computed tomography (CT) are ideal to identify bony changes and CT arthrography also serves as an alternative method in cases of contraindications for MRI. These modalities support the clinically suspected diagnosis of impingement syndrome and may identify its cause in primary diagnosis. In addition, effects of impingement are determined by imaging. Therapy decisions are based on a synopsis of radiological and clinical findings. The sensitivity and specificity of these imaging modalities with regard to the diagnostics of a clinically evident impingement syndrome are given in this review article. Orthopedic and trauma surgeons express the suspicion of an impingement syndrome based on patient history and physical examination and radiologists confirm structural changes and damage of intra-articular structures using dedicated imaging techniques.

  12. THREE-DIMENSIONAL MEAN AND TURBULENCE CHARACTERISTICS OF AN IMPINGING DENSITY JET IN A CONFINED CROSSFLOW IN NEAR FIELD

    Institute of Scientific and Technical Information of China (English)

    FAN Jing-yu; WANG Dao-zeng; ZHANG Yan

    2004-01-01

    The three-dimensional mean and turbulence characteristics of an impinging density jet in a confined crossflow were numerically investigated using the RNG turbulence model. The comparison of the subregion structures and gross features between the numerical results and the experimental data show good agreement. The velocity, Turbulent Kinetic Energy (TKE) and concentration distributions of the impinging jet in near field were obtained and analyzed. The results indicate that the flow and concentration fields of the impinging jet in the crossflow exhibit distinguished three-dimensionality in the near field. There exist upstream wall vortices and downstream wall jet zones in the impinging region, and the TKE and concentration decays are asymmetrical in relation to the stagnation point. The lateral concentration distribution range in the impinging region spreads considerably. The enhanced entrainment and mixing of the impinging jet in the confined crossflow are mostly associated with the impinging action and lateral expansion in the impinging region. The presence of the bottom wall restrains the formation of the spanwise rollers in the transverse jet region and vertical entrainment and mixing in the impinging region and the transition region.

  13. Rhabdoid Tumor Mimicking Hemangioma

    NARCIS (Netherlands)

    Assen, Yvette J.; Madern, Gerard C.; de Laat, Peter C. J.; den Hollander, Jan C.; Oranje, Arnold P.

    2011-01-01

    We report a young boy with a malignant tumor, which remained unrecognized for 8 months because it was assumed to be a hemangioma. The presentation of a rhabdoid tumor mimicking hemangioma is very rare. It was reported only on two earlier occasions. Rhabdoid tumors are one of the most aggressive type

  14. Rhabdoid Tumor Mimicking Hemangioma

    NARCIS (Netherlands)

    Assen, Yvette J.; Madern, Gerard C.; de Laat, Peter C. J.; den Hollander, Jan C.; Oranje, Arnold P.

    2011-01-01

    We report a young boy with a malignant tumor, which remained unrecognized for 8 months because it was assumed to be a hemangioma. The presentation of a rhabdoid tumor mimicking hemangioma is very rare. It was reported only on two earlier occasions. Rhabdoid tumors are one of the most aggressive

  15. CFD study of turbulent jet impingement on curved surface

    Institute of Scientific and Technical Information of China (English)

    Javad Taghinia; Md Mizanur Rahman; Timo Siikonen

    2016-01-01

    The heat transfer and flow characteristics of air jet impingement on a curved surface are investigated with com-putational fluid dynamics (CFD) approach. The first applied model is a one-equation SGS model for large eddy simulation (LES) and the second one is the SST-SAS hybrid RANS-LES. These models are utilized to study the flow physics in impinging process on a curved surface for different jet-to-surface (h/B) distances at two Reynolds numbers namely, 2960 and 4740 based on the jet exit velocity (Ue) and the hydraulic diameter (2B). The predic-tions are compared with the experimental data in the literature and also the results from RANS k-εmodel. Com-parisons show that both models can produce relatively good results. However, one-equation model (OEM) produced more accurate results especial y at impingement region at lower jet-to-surface distances. In terms of heat transfer, the OEM also predicted better at different jet-to-surface spacings. It is also observed that both models show similar performance at higher h/B ratios.

  16. Rotation Effect on Jet Impingement Heat Transfer in Smooth Rectangular Channels with Film Coolant Extraction

    Directory of Open Access Journals (Sweden)

    James A. Parsons

    2001-01-01

    Full Text Available The effect of channel rotation on jet impingement cooling by arrays of circular jets in twin channels was studied. Impinging jet flows were in the direction of rotation in one channel and opposite to the direction of rotation in the other channel. The jets impinged normally on the smooth, heated target wall in each channel. The spent air exited the channels through extraction holes in each target wall, which eliminates cross flow on other jets. Jet rotation numbers and jet Reynolds numbers varied from 0.0 to 0.0028 and 5000 to 10,000, respectively. For the target walls with jet flow in the direction of rotation (or opposite to the direction of rotation, as rotation number increases heat transfer decreases up to 25% (or 15% as compared to corresponding results for non-rotating conditions. This is due to the changes in flow distribution and rotation induced Coriolis and centrifugal forces.

  17. Enhancements of Impinging Flame by Pulsation

    Institute of Scientific and Technical Information of China (English)

    AySu; Ying-ChiehLiu

    2000-01-01

    Experimental investigations on the pulsating jet-impinging diffusion flame were executed.A soleoid valve was aligned upstream of the jet orifice and the methane fuel was controlled in open-closed cycles from 0 Hz to 20Hz.Results show that the open-closed cycles,indeed increase the fluctuations of the methane fuel obviously.The evolutions of pulsating flame therefore develop faster than the continuous impinging flame.The optimized pulating frequencies are near 9 to 11 hz from the Re=170 to 283.The temperature differences between that under optimized pulsating rate and full open condition(no pulsation)are ranging from 100 to 150 degree.The pulsating effect is more singnificant at low Reynolds number.The cross section of continuous impinging flame behaves as elliptic shape with axial ratio equals to 2/3.The tip of the impinging flame obviously crosses at 42mm above the impinging point.ecause of the phenomenon of pulsation flame,the flame sheet or flame front may not be identified clearly in the averaged temperature contours.Results shows that the averaged end-contour of pulsation flame rears at 38mm above the impinging point.By observation and experiment,the pulsating flame behaves more stable and efficient than the continuous impinging flame.

  18. Study of Plume Impingement Effects in the Lunar Lander Environment

    Science.gov (United States)

    Marichalar, Jeremiah; Prisbell, A.; Lumpkin, F.; LeBeau, G.

    2010-01-01

    Plume impingement effects from the descent and ascent engine firings of the Lunar Lander were analyzed in support of the Lunar Architecture Team under the Constellation Program. The descent stage analysis was performed to obtain shear and pressure forces on the lunar surface as well as velocity and density profiles in the flow field in an effort to understand lunar soil erosion and ejected soil impact damage which was analyzed as part of a separate study. A CFD/DSMC decoupled methodology was used with the Bird continuum breakdown parameter to distinguish the continuum flow from the rarefied flow. The ascent stage analysis was performed to ascertain the forces and moments acting on the Lunar Lander Ascent Module due to the firing of the main engine on take-off. The Reacting and Multiphase Program (RAMP) method of characteristics (MOC) code was used to model the continuum region of the nozzle plume, and the Direct Simulation Monte Carlo (DSMC) Analysis Code (DAC) was used to model the impingement results in the rarefied region. The ascent module (AM) was analyzed for various pitch and yaw rotations and for various heights in relation to the descent module (DM). For the ascent stage analysis, the plume inflow boundary was located near the nozzle exit plane in a region where the flow number density was large enough to make the DSMC solution computationally expensive. Therefore, a scaling coefficient was used to make the DSMC solution more computationally manageable. An analysis of the effectiveness of this scaling technique was performed by investigating various scaling parameters for a single height and rotation of the AM. Because the inflow boundary was near the nozzle exit plane, another analysis was performed investigating three different inflow contours to determine the effects of the flow expansion around the nozzle lip on the final plume impingement results.

  19. Traction Drive Inverter Cooling with Submerged Liquid Jet Impingement on Microfinned Enhanced Surfaces (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S.; Narumanchi, S.; Moreno, G.

    2014-09-01

    Jet impingement is one means to improve thermal management for power electronics in electric-drive traction vehicles. Jet impingement on microfin-enhanced surfaces further augments heat transfer and thermal performance. A channel flow heat exchanger from a commercial inverter was characterized as a baseline system for comparison with two new prototype designs using liquid jet impingement on plain and microfinned enhanced surfaces. The submerged jets can target areas with the highest heat flux to provide local cooling, such as areas under insulated-gate bipolar transistors and diode devices. Low power experiments, where four diodes were powered, dissipated 105 W of heat and were used to validate computational fluid dynamics modeling of the baseline and prototype designs. Experiments and modeling used typical automotive flow rates using water-ethylene glycol as a coolant (50%-50% by volume). The computational fluid dynamics model was used to predict full inverter power heat dissipation. The channel flow and jet impingement configurations were tested at full inverter power of 40 to 100 kW (output power) on a dynamometer, translating to an approximate heat dissipation of 1 to 2 kW. With jet impingement, the cold plate material is not critical for the thermal pathway. A high-temperature plastic was used that could eventually be injection molded or formed, with the jets formed from a basic aluminum plate with orifices acting as nozzles. Long-term reliability of the jet nozzles and impingement on enhanced surfaces was examined. For jet impingement on microfinned surfaces, thermal performance increased 17%. Along with a weight reduction of approximately 3 kg, the specific power (kW/kg) increased by 36%, with an increase in power density (kW/L) of 12% compared with the baseline channel flow configuration.

  20. Necrobiosis lipoidica mimicking cellulitis

    Directory of Open Access Journals (Sweden)

    Joshi A

    1997-01-01

    Full Text Available A 57-year-old obese patient presented with a 5 month history of tender, indurated, erythematous plaques with superficial ulceration on the right shin. The lesions closely mimicked cellulitis but were unresponsive to antibiotics. Though the patient was not a known diabetic, on investigations she was found to be a diabetic. Histology confirmed the diagnosis of necrobiosis lipoidica. This acutely inflammed presentation of necrobiosis lipoidica is extremely rare.

  1. Directional transport of impinging capillary jet on wettability engineered surfaces

    Science.gov (United States)

    Ghosh, Aritra; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Impingement of capillary jet on a surface is important for applications like heat transfer, or for liquid manipulation in bio-microfluidic devices. Using wettability engineered surfaces, we demonstrate pump-less and directional transport of capillary jet on a flat surface. Spatial contrast of surface energy and a wedge-shape geometry of the wettability confined track on the substrate facilitate formation of instantaneous spherical bulges upon jet impingement; these bulges are further transported along the superhydrophilic tracks due to Laplace pressure gradient. Critical condition warranted for formation of liquid bulge along the varying width of the superhydrophilic track is calculated analytically and verified experimentally. The work throws light on novel fluid phenomena of unidirectional jet impingement on wettability confined surfaces and provides a platform for innovative liquid manipulation technique for further application. By varying the geometry and wettability contrast on the surface, one can achieve volume flow rates of ~ O(100 μL/sec) and directionally guided transport of the jet liquid, pumplessly at speeds of ~ O(10cm/sec).

  2. Statistics of fully turbulent impinging jets

    CERN Document Server

    Wilke, Robert

    2016-01-01

    Direct numerical simulations of sub- and supersonic impinging jets with Reynolds numbers of 3300 and 8000 are carried out to analyse their statistical properties. The influence of the parameters Mach number, Reynolds number and ambient temperature on the mean velocity and temperature fields are studied. For the compressible subsonic cold impinging jets into a heated environment, different Reynolds analogies are assesses. It is shown, that the (original) Reynolds analogy as well as the Chilton Colburn analogy are in good agreement with the DNS data outside the impinging area. The generalised Reynolds analogy (GRA) and the Crocco-Busemann relation are not suited for the estimation of the mean temperature field based on the mean velocity field of impinging jets. Furthermore, the prediction of fluctuating temperatures according to the GRA fails. On the contrary, the linear relation between thermodynamic fluctuations of entropy, density and temperature as suggested by Lechner et al. (2001) can be confirmed for the...

  3. Radiological diagnosis of femoroacetabular impingement; Radiologische Diagnose des femoroazetabulaeren Impingements

    Energy Technology Data Exchange (ETDEWEB)

    Mamisch, T.C. [Inselspital, Abt. Orthopaedische Chirurgie, Bern (Switzerland); Klinik Sonnenhof, Abt. Radiologie, Bern (Switzerland); Werlen, S.; Trattnig, S. [Klinik Sonnenhof, Abt. Radiologie, Bern (Switzerland); Zilkens, C. [Universitaetsklinikum Duesseldorf, Orthopaedische Klinik, Duesseldorf (Germany); Kim, Y.J. [Harvard Medical School, Childrens Hospital, Boston, MA (United States); Siebenrock, K.A.; Bittersohl, B. [Inselspital, Abt. Orthopaedische Chirurgie, Bern (Switzerland)

    2009-05-15

    Femoroacetabular impingements (FAI) are due to an anatomical disproportion between the proximal femur and the acetabulum which causes premature wear of the joint surfaces. An operation is often necessary in order to relieve symptoms such as limited movement and pain as well as to prevent or slow down the degenerative process. The result is dependent on the preoperative status of the joint with poor results for advanced arthritis of the hip joint. This explains the necessity for an accurate diagnosis in order to recognize early stages of damage to the joint. The diagnosis of FAI includes clinical examination, X-ray examination and magnetic resonance imaging (MRI). The standard X-radiological examination for FAI is carried out using two X-ray images, an anterior-posterior view of the pelvis and a lateral view of the proximal femur, such as the cross-table lateral or Lauenstein projections. It is necessary that positioning criteria are adhered to in order to avoid distortion artifacts. MRI permits an examination of the pelvis on three levels and should also include radial planned sequences for improved representation of peripheral structures, such as the labrum and peripheral cartilage. The use of contrast medium for a direct MR arthrogram has proved to be advantageous particularly for representation of labrum damage. The data with respect to cartilage imaging are still unclear. Further developments in technology, such as biochemical-sensitive MRI applications, will be able to improve the diagnosis of the pelvis in the near future. (orig.) [German] Beim femoroazetabulaeren Impingement (FAI) bewirkt ein anatomisches Missverhaeltnis zwischen proximalem Femur und Azetabulum eine fruehzeitige Abnuetzung der Gelenkflaechen. Um Symptome wie eingeschraenkte Beweglichkeit und Schmerzen zu beheben, aber auch um dem degenerativen Prozess vorzubeugen oder ihn zu verlangsamen, ist haeufig eine Operation notwendig. Dabei haengt das Resultat vom praeoperativen Gelenkstatus ab - mit

  4. Internal Impingement of the Shoulder: A Risk of False Positive Test Outcomes in External Impingement Tests?

    Directory of Open Access Journals (Sweden)

    Tim Leschinger

    2017-01-01

    Full Text Available Background. External impingement tests are considered as being particularly reliable for identifying subacromial and coracoid shoulder impingement mechanisms. The purpose of the present study was to evaluate if these tests are likely to provoke an internal shoulder impingement mechanism which, in cases of a pathologic condition, can lead to a positive test result. Method. In 37 subjects, the mechanical contact between the glenoid rim and the rotator cuff (RC was measured quantitatively and qualitatively in external impingement test positions using an open MRI system. Results. Mechanical contact of the supraspinatus with the posterosuperior glenoid was present in 30 subjects in the Neer test. In the Hawkins test, the subscapularis was in contact with the anterosuperior glenoid in 33 subjects and the supraspinatus in 18. In the horizontal impingement test, anterosuperior contact of the supraspinatus with the glenoid was identified in 35 subjects. Conclusion. The Neer, Hawkins, and horizontal impingement tests are likely to provoke the mechanism of an internal shoulder impingement. A posterosuperior internal impingement mechanism is being provoked predominately in the Neer test. The Hawkins test narrows the distance between the insertions of the subscapularis and supraspinatus and the anterosuperior labrum, which leads to an anterosuperior impingement mechanism.

  5. Achilles Impingement Tendinopathy on Magnetic Resonance Imaging.

    Science.gov (United States)

    Bullock, Mark J; Mourelatos, Jan; Mar, Alice

    2017-02-28

    Haglund's syndrome is impingement of the retrocalcaneal bursa and Achilles tendon caused by a prominence of the posterosuperior calcaneus. Radiographic measurements are not sensitive or specific for diagnosing Haglund's deformity. Localization of a bone deformity and tendinopathy in the same sagittal section of a magnetic resonance imaging scan can assist with the diagnosis in equivocal cases. The aim of the present cross-sectional study was to determine the prevalence of Haglund's syndrome in patients presenting with Achilles tendinopathy and note any associated findings to determine the criteria for a diagnosis of Haglund's syndrome. We reviewed 40 magnetic resonance imaging scans with Achilles tendinopathy and 19 magnetic resonance imaging scans with Achilles high-grade tears and/or ruptures. Achilles tendinopathy was often in close proximity to the superior aspect of the calcaneal tuberosity, consistent with impingement (67.5%). Patients with Achilles impingement tendinopathy were more often female (p < .04) and were significantly heavier than patients presenting with noninsertional Achilles tendinopathy (p = .014) or Achilles tendon rupture (p = .010). Impingement tendinopathy occurred medially (8 of 20) and centrally (10 of 20) more often than laterally (2 of 20) and was associated with a posterior prominence or hyperconvexity with a loss of calcaneal recess more often than a superior projection (22 of 27 versus 8 of 27; p < .001). Haglund's deformity should be reserved for defining a posterior prominence or hyperconvexity with loss of calcaneal recess because this corresponds with impingement. Achilles impingement tendinopathy might be more appropriate terminology for Haglund's syndrome, because the bone deformity is often subtle. Of the 27 images with Achilles impingement tendinopathy, 10 (37.0%) extended to a location prone to Achilles tendon rupture. Given these findings, insertional and noninsertional Achilles tendinopathy are not mutually

  6. Simulating regolith ejecta due to gas impingement

    Science.gov (United States)

    Chambers, Wesley Allen; Metzger, Philip; Dove, Adrienne; Britt, Daniel

    2016-10-01

    Space missions operating at or near the surface of a planet or small body must consider possible gas-regolith interactions, as they can cause hazardous effects or, conversely, be employed to accomplish mission goals. They are also directly related to a body's surface properties; thus understanding these interactions could provide an additional tool to analyze mission data. The Python Regolith Interaction Calculator (PyRIC), built upon a computational technique developed in the Apollo era, was used to assess interactions between rocket exhaust and an asteroid's surface. It focused specifically on threshold conditions for causing regolith ejecta. To improve this model, and learn more about the underlying physics, we have begun ground-based experiments studying the interaction between gas impingement and regolith simulant. Compressed air, initially standing in for rocket exhaust, is directed through a rocket nozzle at a bed of simulant. We assess the qualitative behavior of various simulants when subjected to a known maximum surface pressure, both in atmosphere and in a chamber initially at vacuum. These behaviors are compared to prior computational results, and possible flow patterns are inferred. Our future work will continue these experiments in microgravity through the use of a drop tower. These will use several simulant types and various pressure levels to observe the effects gas flow can have on target surfaces. Combining this with a characterization of the surface pressure distribution, tighter bounds can be set on the cohesive threshold necessary to maintain regolith integrity. This will aid the characterization of actual regolith distributions, as well as informing the surface operation phase of mission design.

  7. Modeling a Midlatitude Cyclone Impinging on Localized Orography

    Science.gov (United States)

    Menchaca, Maximo Q.

    Idealized studies of mountain waves have primarily focused on the steady state response to horizontally uniform flows encountering an obstacle. In this research, we extend previous studies of nonsteady mountain waves to examine their generation, propagation, and dissipation when forced by a midlatitude cyclone impinging on an isolated ridge. The cyclone is obtained by superimposing a localized finite amplitude potential vorticity anomaly on a baroclinically unstable jet. We minimize transient gravity waves with the use of a digital filter. Localized terrain is placed in an initially quiescent region of the flow, away from the initial PV anomaly. The maturing cyclone propagates towards the terrain, generating gravity waves exhibiting strong time dependent behavior that is affected by the changing flow. Significant wave genesis is tied to the passage of surface fronts and their accompanying jet streaks and stronger surface winds. Wave packets advect downstream after front passage, causing noticeable wave-mean flow interaction. Waves generated by cold fronts impinging on terrain are compared with mountain waves generated by warm fronts, allowing for exploration into the influence of directional shear on the waves. Mountain waves produced by warm fronts have shorter horizontal and vertical wavelength and do not propagate far from their source compared with mountain waves produced by cold fronts. These simulations also produce many other realistic features, including wave breaking and downslope windstorms.

  8. Experimental study of turbulence in isothermal jet impingement at intermediate plate spacings

    Science.gov (United States)

    Landfried, D. Tyler; Valentino, Alex; Mazumdar, Sagnik; Jana, Anirban; Kimber, Mark

    2013-11-01

    One fundamental problem in fluid dynamics is that of the axisymmetric round flow impinging on a plate placed some distance downstream of the jet. Impinging jets have a rich history of applications including small plate spacings, H/D ~ 1, such as encountered in electronics cooling, or large plate spacings, H/D ~ 102, such as vertical takeoff aircrafts and rocket engines. However, intermediate plate spacings, such as the lower plenum of the next generation nuclear reactors, are not typically studied. In this paper, an experimental study is conducted investigating the effect of the impingement plate on the flow behavior compared to the near free jet behavior when the plate is removed. Using air as the working fluid, a single jet is considered at jet Reynolds numbers of 10000, 20000, and 30000. A three-wire anemometer probe is used to quantify the mean components of velocities as well as the Reynolds stress and the third-order moments in the flow field at various distances between the jet outlet and the impingement plate. When present, the impingement plate is placed a distance of 8, 11, 14, and 17 diameters downstream of the jet. Additionally trends in the kinetic energy and dissipation are investigated for validation with numerical models.

  9. Investigation of impinging jet resonant modes using unsteady pressure-sensitive paint measurements

    Science.gov (United States)

    Davis, Timothy; Edstrand, Adam; Alvi, Farrukh; Cattafesta, Louis; Yorita, Daisuke; Asai, Keisuke

    2015-05-01

    At given nozzle to plate spacings, the flow field of high-speed impinging jets is known to be characterized by a resonance phenomenon. Large coherent structures that convect downstream and impinge on the surface create strong acoustic waves that interact with the inherently unstable shear layer at the nozzle exit. This feedback mechanism, driven by the coherent structures in the jet shear layer, can either be axisymmetric or helical in nature. Fast-response pressure-sensitive paint (PSP) is applied to the impingement surface to map the unsteady pressure distribution associated with these resonant modes. Phase-averaged results acquired at several kHz are obtained using a flush mounted unsteady pressure transducer on the impingement plate as a reference signal. Tests are conducted on a Mach 1.5 jet at nozzle to plate spacings of . The resulting phase-averaged distribution reveals dramatically different flow fields at the corresponding impingement heights. The existence of a purely axisymmetric mode with a frequency of 6.3 kHz is identified at and is characterized by concentric rings of higher/lower pressure that propagate radially with increasing phase. Two simultaneous modes are observed at with one being a dominant symmetric mode at 7.1 kHz and the second a sub-dominant helical mode at 4.3 kHz. Complimentary phase-conditioned Schlieren images are also obtained visualizing the flow structures associated with each mode and are consistent with the PSP results.

  10. Convective heat transfer under unsteady impinging jets: the effect of the shape of the unsteadiness

    Science.gov (United States)

    Middelberg, G.; Herwig, H.

    2009-10-01

    Unsteady impinging jets are systematically controlled with respect to their time dependence in order to investigate the influence of unsteadiness on the heat transfer performance. This is achieved by a special mass flow control device, which allows almost arbitrary shapes of unsteadiness to be imposed onto the impinging jet. Three different standard signals (sinusoidal, triangular, rectangular) and two specially designed signals are applied and their influence on heat transfer is determined in terms of an enhancement factor. Heat transfer augmentation up to 30% was found and could be physically explained with the help of PIV and hot-wire measurements of the flow field.

  11. Pelvic morphology in ischiofemoral impingement

    Energy Technology Data Exchange (ETDEWEB)

    Bredella, Miriam A.; Azevedo, Debora C.; Oliveira, Adriana L.; Simeone, Frank J.; Chang, Connie Y.; Torriani, Martin [Massachusetts General Hospital, Department of Radiology, Musculoskeletal Imaging and Intervention, Boston, MA (United States); Stubbs, Allston J. [Wake Forest University School of Medicine, Department of Orthopedic Surgery, Division of Sports Medicine, Winston-Salem, NC (United States)

    2014-11-06

    To assess MRI measures to quantify pelvic morphology that may predispose to ischiofemoral impingement (IFI). We hypothesized that patients with IFI have a wider interischial distance and an increased femoral neck angle compared with normal controls. The study was IRB-approved and complied with HIPAA guidelines. IFI was diagnosed based on clinical findings (hip or buttock pain) and ipsilateral edema of the quadratus femoris muscle on MRI. Control subjects did not report isolated hip/buttock pain and underwent MRI for surveillance of neoplasms or to exclude pelvic fractures. Two MSK radiologists measured the ischiofemoral (IF) and quadratus femoris (QF) distance, the ischial angle as a measure of inter-ischial distance, and the femoral neck angle. The quadratus femoris muscle was evaluated for edema. Groups were compared using ANOVA. Multivariate standard least-squares regression modeling was used to control for age and gender. The study group comprised 84 patients with IFI (53 ± 16 years, 73 female, 11 male) and 51 controls (52 ± 16 years, 33 female, 18 male). Thirteen out of 84 patients (15 %) had bilateral IFI. Patients with IFI had decreased IF and QF distance (p < 0.0001), increased ischial angle (p = 0.004), and increased femoral neck angle (p = 0.02) compared with controls, independent of age and gender. Patients with IFI have increased ischial and femoral neck angles compared with controls. These anatomical variations in pelvic morphology may predispose to IFI. MRI is a useful method of not only assessing the osseous and soft-tissue abnormalities associated with IFI, but also of quantifying anatomical variations in pelvic morphology that can predispose to IFI. (orig.)

  12. Unsteady conjugate heat transfer analysis for impinging jet cooling

    Science.gov (United States)

    Tejero, F.; Flaszyński, P.; Szwaba, R.; Telega, J.

    2016-10-01

    The paper presents the numerical investigations of the heat transfer on a flat plate cooled by a single impinging jet. The thermal conductivity of the plate was modified from a high thermal case (steel -λ= 35 W/m/K) to a low one (steel alloy Inconel -λ= 9.8 W/m/K). The numerical simulations results are compared with the experimental data from the Institute of Fluid-Flow Machinery Polish Academy of Sciences, Gdansk (Poland). The numerical simulations are carried out by means of Ansys/Fluent and k-ω SST turbulence model and the temperature evolution on the target plate is investigated by conjugated heat transfer computations.

  13. Physical Modelling of Axisymmetric Turbulent Impinging Jets as used within the Nuclear Industry for Mobilisation of Sludges

    Energy Technology Data Exchange (ETDEWEB)

    McKendrick, D.; Biggs, S.R.; Fairweather, M. [Institute of Particle Science and Engineering, University of Leeds, Leeds (United Kingdom); Rhodes, D. [Nexia Solutions, Sellafield, Seascale, Cumbria (United Kingdom)

    2008-07-01

    The impingement of a fluid jet onto a surface has broad applications across many industries. Within the UK nuclear industry, during the final stages of fuel reprocessing, impinging fluid jets are utilised to mobilise settled sludge material within storage tanks and ponds in preparation for transfer and ultimate immobilisation through vitrification. Despite the extensive applications of impinging jets within the nuclear and other industries, the study of two-phase, solid loaded, impinging jets is limited, and generally restricted to computational modelling. Surprisingly, very little fundamental understanding of the turbulence structure within such fluid flows through experimental investigation is found within the literature. The physical modelling of impinging jet systems could successfully serve to aid computer model validation, determine operating requirements, evaluate plant throughput requirements, optimise process operations and support design. Within this project a method is illustrated, capable of exploring the effects of process and material variables on flow phenomena of impinging jets. This is achieved via the use of non-intrusive measurement techniques Particle Image Velocimetry (PIV), Ultrasonic Doppler Velocity Profiler (UDVP) and high speed imaging. The turbulence structure for impinging jets, and their resultant radial wall jets, is presented at different jet-to-plate ratios, jet Reynolds numbers and jet outlet diameters. (authors)

  14. Self—Induced Oscillation of Supersonic Jet During Impingement on Cylindrical Body

    Institute of Scientific and Technical Information of China (English)

    HideoKashimura; ShenYu; 等

    1998-01-01

    The phenomena of the interaction between a supersonic jet and an obstacle are related to the problems of the aeronautical and other industrial engineerings.When a supersonic jet impinges on an obstacle,the self induced oscillation occurs under several conditions.The flow charactersitics caused by the impingement of underexpanded supersonic jet on an obstacle have been investigated.However,it seems that the mechanism of self induced oscillation and the factor which dominates if have not been detailed in the published papers,The characteristics of the self induced oscillation of the supersonic jet during the impingement on a cylindrical body are investigated using the visualization of flow fields and the numerical calculations in this study.

  15. Global mode decomposition of supersonic impinging jet noise

    Science.gov (United States)

    Hildebrand, Nathaniel; Nichols, Joseph W.

    2015-11-01

    We apply global stability analysis to an ideally expanded, Mach 1.5, turbulent jet that impinges on a flat surface. The analysis extracts axisymmetric and helical instability modes, involving coherent vortices, shocks, and acoustic feedback, which we use to help explain and predict the effectiveness of microjet control. High-fidelity large eddy simulations (LES) were performed at nozzle-to-wall distances of 4 and 4.5 throat diameters with and without sixteen microjets positioned uniformly around the nozzle lip. These flow configurations conform exactly to experiments performed at Florida State University. Stability analysis about LES mean fields predicted the least stable global mode with a frequency that matched the impingement tone observed in experiments at a nozzle-to-wall distance of 4 throat diameters. The Reynolds-averaged Navier-Stokes (RANS) equations were solved at five nozzle-to-wall distances to create base flows that were used to investigate the influence of this parameter. A comparison of the eigenvalue spectra computed from the stability analysis about LES and RANS base flows resulted in good agreement. We also investigate the effect of the boundary layer state as it emerges from the nozzle using a multi-block global mode solver. Computational resources were provided by the Argonne Leadership Computing Facility.

  16. Impingement of water droplets on wedges and diamond airfoils at supersonic speeds

    Science.gov (United States)

    Serafini, John S

    1953-01-01

    An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees to 460 degrees R. Also, free-stream Mach numbers from 1.1 to 2.0, semi-apex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

  17. Impingement of water droplets on wedges and double-wedge airfoils at supersonic speeds

    Science.gov (United States)

    Serafini, John S

    1954-01-01

    An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees r, free stream Mach numbers from 1.1 to 2.0, semiapex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

  18. Experimental and numerical investigation of liquid jet impingement on superhydrophobic and hydrophobic convex surfaces

    Science.gov (United States)

    Kibar, Ali

    2017-02-01

    Experiments and numerical simulations were carried out to examine the vertical impingement a round liquid jet on the edges of horizontal convex surfaces that were either superhydrophobic or hydrophobic. The experiments examine the effects on the flow behaviour of curvature, wettability, inertia of the jet, and the impingement rate. Three copper pipes with outer diameters of 15, 22, and 35 mm were investigated. The pipes were wrapped with a piece of a Brassica oleracea leaf or a smooth Teflon sheet, which have apparent contact angles of 160° and 113°. The Reynolds number ranged from 1000 to 4500, and the impingement rates of the liquid jets were varied. Numerical results show good agreement with the experimental results for explaining flow and provide detailed information about the impingement on the surfaces. The liquid jet reflected off the superhydrophobic surfaces for all conditions. However, the jet reflected or deflected off the hydrophobic surface, depending on the inertia of the jet, the curvature of the surface, and the impingement rate. The results suggest that pressure is not the main reason for the bending of the jet around the curved hydrophobic surface.

  19. Noise Characteristics of a Four-Jet Impingement Device Inside a Broadband Engine Noise Simulator

    Science.gov (United States)

    Brehm, Christoph; Housman, Jeffrey A.; Kiris, Cetin C.; Hutcheson, Florence V.

    2015-01-01

    The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order accurate weighted essentially non-oscillatory shock-capturing scheme. Impinging jet devices are often used as an experimental apparatus to emulate a broadband noise source. Although such devices have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. Thus, the underlying physical mechanisms that are responsible for the generation of sound waves are not well understood. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition of the flow field is utilized to characterize the unsteady nature of the flow field involving unsteady shock oscillations, large coherent turbulent flow structures, and the sporadic appearance of vortex tubes in the center of the impingement region. The causality method based on Lighthill's acoustic analogy is applied to link fluctuations of flow quantities inside the source region to the acoustic pressure in the far field. It will be demonstrated that the entropy fluctuation term in the Lighthill's stress tensor plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a reduced-order linear acoustic model of the four-jet impingement device. Finally, three linear acoustic FJID models are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data.

  20. Imaging findings of femoroacetabular impingement syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Beall, Douglas P.; Sweet, Clifford F.; Martin, Hal D.; Lastine, Craig L.; Grayson, David E.; Ly, Justin Q.; Fish, Jon R. [University of Oklahoma Health Sciences Center, Department of Radiologal Sciences, Oklahoma City (United States)

    2005-11-01

    Femoroacetabular impingement syndrome (FAI) is a pathologic entity which can lead to chronic symptoms of pain, reduced range of motion in flexion and internal rotation, and has been shown to correlate with degenerative arthritis of the hip. History, physical examination, and supportive radiographic findings such as evidence of articular cartilage damage, acetabular labral tearing, and early-onset degenerative changes can help physicians diagnose this entity. Several pathologic changes of the femur and acetabulum are known to predispose patients to develop FAI and recognition of these findings can ultimately lead to therapeutic interventions. The two basic mechanisms of impingement - cam impingement and pincer impingement - are based on the type of anatomic anomaly contributing to the impingement process. These changes can be found on conventional radiography, MR imaging, and CT examinations. However, the radiographic findings of this entity are not widely discussed and recognized by physicians. In this paper, we will introduce these risk factors, the proposed supportive imaging criteria, and the ultimate interventions that can help alleviate patients' symptoms. (orig.)

  1. Industrial stator vane with sequential impingement cooling inserts

    Science.gov (United States)

    Jones, Russell B; Fedock, John A; Goebel, Gloria E; Krueger, Judson J; Rawlings, Christopher K; Memmen, Robert L

    2013-08-06

    A turbine stator vane for an industrial engine, the vane having two impingement cooling inserts that produce a series of impingement cooling from the pressure side to the suction side of the vane walls. Each insert includes a spar with a row of alternating impingement cooling channels and return air channels extending in a radial direction. Impingement cooling plates cover the two sides of the insert and having rows of impingement cooling holes aligned with the impingement cooling channels and return air openings aligned with the return air channel.

  2. Analytical Study on Impingement Heat Transfer with Single—Phase Free—Surface Circular Liquid Jets

    Institute of Scientific and Technical Information of China (English)

    C.F.Ma; T.Masuoka; 等

    1996-01-01

    An analytical research was conducted to study heat transfer from horizontal surfaces to normally impinging circular jets under arbitrary-heat-flux conditions.The laminar thermal and hydraulic bound ary layers were divided into five regions of flow.General expressions of heat transfer coefficients were obtained in all the four regions of stagnation and wall jet zones before the hydraulic jump.

  3. Impinging jet study of the deposition of colloidal particles on synthetic polymer (Zeonor)

    DEFF Research Database (Denmark)

    Vlček, Jakub; Lapčík, Lubomír; Cech, Jiri

    2014-01-01

    In this study, an impinging jet deposition experiments were performed on synthetic polymer (Zeonor) original and by micro-embossing modified substrates with exactly defined topology as confirmed by AFM and SEM. Deposition experiments were performed at ambient temperature and at selected flow regime...

  4. Outdoor Performance Analysis of a Photovoltaic Thermal (PVT Collector with Jet Impingement and Compound Parabolic Concentrator (CPC

    Directory of Open Access Journals (Sweden)

    Ahed Hameed Jaaz

    2017-08-01

    Full Text Available This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT collector and compound parabolic concentrators (CPC on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m2 and an ambient temperature of 33.5 °C. It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV module at 1:30 p.m. The short-circuit current ISC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC.

  5. Outdoor Performance Analysis of a Photovoltaic Thermal (PVT) Collector with Jet Impingement and Compound Parabolic Concentrator (CPC)

    Science.gov (United States)

    Jaaz, Ahed Hameed; Hasan, Husam Abdulrasool; Sopian, Kamaruzzaman; Kadhum, Abdul Amir H.; Gaaz, Tayser Sumer

    2017-01-01

    This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT) collector and compound parabolic concentrators (CPC) on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m2 and an ambient temperature of 33.5 °C). It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV) module at 1:30 p.m. The short-circuit current ISC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC. PMID:28763048

  6. Outdoor Performance Analysis of a Photovoltaic Thermal (PVT) Collector with Jet Impingement and Compound Parabolic Concentrator (CPC).

    Science.gov (United States)

    Jaaz, Ahed Hameed; Hasan, Husam Abdulrasool; Sopian, Kamaruzzaman; Kadhum, Abdul Amir H; Gaaz, Tayser Sumer; Al-Amiery, Ahmed A

    2017-08-01

    This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT) collector and compound parabolic concentrators (CPC) on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m² and an ambient temperature of 33.5 °C). It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV) module at 1:30 p.m. The short-circuit current ISC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC.

  7. Study on the two-dimensional jet impinging on a circular cylinder. 1st report. ; Measurements of flow-field and heat transfer around a circular cylinder mounted near two flat plates. Enchu eno nijigen shototsu funryu ni kansuru kenkyu. 1. ; Enchu ni kinsetsushite secchishita heiban no nagareba oyobi enchu netsudentatsu eno eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Haneda, Y.; Kurasawa, H. (Nagano National College of Technology, Nagano (Japan)); Tsuchiya, Y. (Shinshu Univ., Nagano (Japan). Faculty of Engineering); Suzuki, K. (Kyoto Univ., Kyoto (Japan). Faculty of Engineering)

    1994-04-25

    The flow field and heat transfer around a circular cylinder is investigated experimentally when two dimensional jet is impinged on a circular cylinder mounted near two flat plates which are set at a fixed inclination against the axis of jet. Flow field varies markedly depending on whether the minimum channel width is the minimum space B between the flat plates or the space C between the cylinder and the plates. The local Nusselt number of the cylinder strongly depends on the value of space C between the cylinder and the plates. The minimum and maximum locations correspond to the locations of separation and reattachment, respectively, of the flow around the cylinder. When the ratio between the nozzle-to-cylinder distance L and the short side h of the nozzle is 3 (L/h=3), the mean Nusselt number around the cylinder becomes the maximum when C/D is 0.1 where D is the diameter of the cylinder, and increases by about 9 to 12% as compared with the case where no plate is provided. For L/h=7 and L/h=10, the mean Nusselt number does not increase distinctly as compared with the case where no flat plate is provided. 16 refs., 15 figs.

  8. Mathematical modeling of a gas jet impinging on a two phase bath

    Science.gov (United States)

    Delgado-Álvárez, J.; Ramírez-Argáez, Marco A.; González-Rivera, C.

    2012-09-01

    In this work a three phase 3D mathematical model was developed using the Volume Of Fluid (VOF) algorithm, which is able to accurately describe the cavity geometry and size as well as the liquid flow patterns created when a gas jet impinges on a two phase liquid free surface. These phenomena are commonly found in steelmaking operations such as in the Electric Arc Furnace (EAF) and the Basic Oxygen Furnace (BOF) where oxygen jets impinge on a steel bath and they control heat, momentum and mass transfer. The cavity formed in the liquids by the impinging jet depends on a force balance at the free surface where the inertial force of the jet governs these phenomena. The inertial force of the jet and its angle play important roles, being the lowest angle the best choice to shear the bath and promote stronger circulation and better mixing in the liquids.

  9. Numerical study of a confined slot impinging jet with nanofluids.

    Science.gov (United States)

    Manca, Oronzio; Mesolella, Paolo; Nardini, Sergio; Ricci, Daniele

    2011-03-01

    Heat transfer enhancement technology concerns with the aim of developing more efficient systems to satisfy the increasing demands of many applications in the fields of automotive, aerospace, electronic and process industry. A solution for obtaining efficient cooling systems is represented by the use of confined or unconfined impinging jets. Moreover, the possibility of increasing the thermal performances of the working fluids can be taken into account, and the introduction of nanoparticles in a base fluid can be considered. In this article, a numerical investigation on confined impinging slot jet working with a mixture of water and Al2O3 nanoparticles is described. The flow is turbulent and a constant temperature is applied on the impinging. A single-phase model approach has been adopted. Different geometric ratios, particle volume concentrations and Reynolds number have been considered to study the behavior of the system in terms of average and local Nusselt number, convective heat transfer coefficient and required pumping power profiles, temperature fields and stream function contours. The dimensionless stream function contours show that the intensity and size of the vortex structures depend on the confining effects, given by H/W ratio, Reynolds number and particle concentrations. Furthermore, for increasing concentrations, nanofluids realize increasing fluid bulk temperature, as a result of the elevated thermal conductivity of mixtures. The local Nusselt number profiles show the highest values at the stagnation point, and the lowest at the end of the heated plate. The average Nusselt number increases for increasing particle concentrations and Reynolds numbers; moreover, the highest values are observed for H/W = 10, and a maximum increase of 18% is detected at a concentration equal to 6%. The required pumping power as well as Reynolds number increases and particle concentrations grow, which is almost 4.8 times greater than the values calculated in the case of

  10. Numerical study of a confined slot impinging jet with nanofluids

    Directory of Open Access Journals (Sweden)

    Manca Oronzio

    2011-01-01

    Full Text Available Abstract Background Heat transfer enhancement technology concerns with the aim of developing more efficient systems to satisfy the increasing demands of many applications in the fields of automotive, aerospace, electronic and process industry. A solution for obtaining efficient cooling systems is represented by the use of confined or unconfined impinging jets. Moreover, the possibility of increasing the thermal performances of the working fluids can be taken into account, and the introduction of nanoparticles in a base fluid can be considered. Results In this article, a numerical investigation on confined impinging slot jet working with a mixture of water and Al2O3 nanoparticles is described. The flow is turbulent and a constant temperature is applied on the impinging. A single-phase model approach has been adopted. Different geometric ratios, particle volume concentrations and Reynolds number have been considered to study the behavior of the system in terms of average and local Nusselt number, convective heat transfer coefficient and required pumping power profiles, temperature fields and stream function contours. Conclusions The dimensionless stream function contours show that the intensity and size of the vortex structures depend on the confining effects, given by H/W ratio, Reynolds number and particle concentrations. Furthermore, for increasing concentrations, nanofluids realize increasing fluid bulk temperature, as a result of the elevated thermal conductivity of mixtures. The local Nusselt number profiles show the highest values at the stagnation point, and the lowest at the end of the heated plate. The average Nusselt number increases for increasing particle concentrations and Reynolds numbers; moreover, the highest values are observed for H/W = 10, and a maximum increase of 18% is detected at a concentration equal to 6%. The required pumping power as well as Reynolds number increases and particle concentrations grow, which is almost 4

  11. Endoscopic treatment of calcaneo-fibular impingement.

    Science.gov (United States)

    Bauer, T; Deranlot, J; Hardy, Ph

    2011-01-01

    The calcaneo-fibular impingement syndrome is frequent after calcaneal fracture and is linked to the decreased space between the tip of the fibula and the lateral wall of the calcaneus. The reasons for the painful symptoms are mixed with both bony and soft tissue involvement. The abnormal bony contact between the lateral calcaneal cortex and the tip of the fibula depends mainly on the size and localization of the lateral exostosis of the calcaneal wall. The soft tissue impingement is due to the fibrosis and scar tissues in the lateral gutter and to the compression of the peroneal tendons in the retromalleolar groove and under the tip of the malleolus. A 2-portal endoscopic technique is described for the treatment of calcaneo-fibular impingement with bone resection, soft tissue debridement and peroneal tendons release. One of the advantages of this endoscopic technique is the possibility of an assessment and treatment of associated lesions in the same procedure. A subtalar joint fusion can be done before if needed under arthroscopic control. As this endoscopic technique is very efficient to relieve symptoms of calcaneo-fibular impingement and is focused on the most relevant symptoms, it can thus be indicated for most of cases of calcaneal malunions, whatever the type of malunion and depending of the painful symptoms.

  12. SHOULDER MUSCLE IMBALANCE AND SUBACROMIAL IMPINGEMENT SYNDROME IN OVERHEAD ATHLETES

    OpenAIRE

    Page, Phil

    2011-01-01

    Subacromial impingement is a frequent and painful condition among athletes, particularly those involved in overhead sports such as baseball and swimming. There are generally two types of subacromial impingement: structural and functional. While structural impingement is caused by a physical loss of area in the subacromial space due to bony growth or inflammation, functional impingement is a relative loss of subacromial space secondary to altered scapulohumeral mechanics resulting from glenohu...

  13. Fluid dynamics and convective heat transfer in impinging jets through implementation of a high resolution liquid crystal technique

    Science.gov (United States)

    Kim, K.; Wiedner, B.; Camci, C.

    1993-01-01

    A combined convective heat transfer and fluid dynamics investigation in a turbulent round jet impinging on a flat surface is presented. The experimental study uses a high resolution liquid crystal technique for the determination of the convective heat transfer coefficients on the impingement plate. The heat transfer experiments are performed using a transient heat transfer method. The mean flow and the character of turbulent flow in the free jet is presented through five hole probe and hot wire measurements, respectively. The flow field character of the region near the impingement plate plays an important role in the amount of convective heat transfer. Detailed surveys obtained from five hole probe and hot wire measurements are provided. An extensive validation of the liquid crystal based heat transfer method against a conventional technique is also presented. After a complete documentation of the mean and turbulent flow field, the convective heat transfer coefficient distributions on the impingement plate are presented. The near wall of the impingement plate and the free jet region is treated separately. The current heat transfer distributions are compared to other studies available from the literature. The present paper contains complete sets of information on the three dimensional mean flow, turbulent velocity fluctuations, and convective heat transfer to the plate. The experiments also prove that the present nonintrusive heat transfer method is highly effective in obtaining high resolution heat transfer maps with a heat transfer coefficient uncertainty of 5.7 percent.

  14. Numerical investigation of mist/air impingement cooling on ribbed blade leading-edge surface.

    Science.gov (United States)

    Bian, Qingfei; Wang, Jin; Chen, Yi-Tung; Wang, Qiuwang; Zeng, Min

    2017-05-23

    The working gas turbine blades are exposed to the environment of high temperature, especially in the leading-edge region. The mist/air two-phase impingement cooling has been adopted to enhance the heat transfer on blade surfaces and investigate the leading-edge cooling effectiveness. An Euler-Lagrange particle tracking method is used to simulate the two-phase impingement cooling on the blade leading-edge. The mesh dependency test has been carried out and the numerical method is validated based on the available experimental data of mist/air cooling with jet impingement on a concave surface. The cooling effectiveness on three target surfaces is investigated, including the smooth and the ribbed surface with convex/concave columnar ribs. The results show that the cooling effectiveness of the mist/air two-phase flow is better than that of the single-phase flow. When the ribbed surfaces are used, the heat transfer enhancement is significant, the surface cooling effectiveness becomes higher and the convex ribbed surface presents a better performance. With the enhancement of the surface heat transfer, the pressure drop in the impingement zone increases, but the incremental factor of the flow friction is smaller than that of the heat transfer enhancement. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Impingement syndrome of the shoulder; Schulterimpingement

    Energy Technology Data Exchange (ETDEWEB)

    Mayerhoefer, M.E. [Klinische Abteilung fuer Osteologie, Klinik fuer Radiodiagnostik der Universitaet Wien (Austria); Klinische Abteilung Radiodiagnostik fuer chirurgische Faecher, Klinik fuer Radiodiagnostik der Universitaet Wien (Austria); Klinische Abteilung fuer Osteologie, Klinik fuer Radiodiagnostik der Universitaet, Waehringer Guertel 18-20, 1090, Wien (Austria); Breitenseher, M.J. [Klinische Abteilung fuer Osteologie, Klinik fuer Radiodiagnostik der Universitaet Wien (Austria); Waldviertelklinikum Horn (Austria)

    2004-06-01

    The impingement syndrome is a clinical entity characterized by shoulder pain due to primary or secondary mechanical irritation of the rotator cuff. The primary factors for the development of impingement are a curved or hook-shaped anterior acromion as well as subacromial osteophytes, which may lead to tearing of the supraspinatus tendon. Secondary impingement is mainly caused by calcific tendinopathy, glenohumeral instability, os acromiale and degenerative changes of the acromioclavicular joint. Conventional radiographs are initially obtained, mainly for evaluation of the bony structures of the shoulder. If available, sonography can be used for detection of lesions and tears of the rotator cuff. Finally, MR-imaging provides detailed information about the relationship of the acromion and the acromioclavicular joint to the rotator cuff itself. In many cases however, no morphologic cause for impingement syndrome can be found. While patients are initially treated conservatively, chronic disease usually requires surgical intervention. (orig.) [German] Das Impingementsyndrom ist ein klinisches Krankheitsbild multifaktorieller Genese, bei dem es primaer oder sekundaer zu einer schmerzhaften mechanischen Beeintraechtigung der Rotatorenmanschette kommt. Als primaere Faktoren gelten ein gebogener oder hakenfoermiger Vorderrand des Akromions oder von diesem entspringende Osteophyten, was zu Laesionen der Supraspinatussehne fuehren kann. Zu den sekundaeren Faktoren zaehlt man v. a. eine Tendinitis calcarea, eine glenohumerale Instabilitaet, ein Os acromiale sowie degenerative Veraenderungen im Bereich des Akromioklavikulargelenks. Bildgebend steht an erster Stelle ein Nativroentgen, mit dem sich die knoechernen Strukturen gut darstellen lassen. Falls vorhanden, kann in weiterer Folge die Sonographie Auskunft ueber den Zustand der Rotatorenmanschette geben. Mit der MRT schliesslich laesst sich die Beziehung von Akromion und gelenkassoziierten Strukturen zur Rotatorenmanschette

  16. Tumoral calcinosis mimicking recurrent osteosarcoma

    National Research Council Canada - National Science Library

    Petscavage, Jonelle M; Richardson, Michael L

    2009-01-01

    We report a case of a tumoral calcinosis mimicking the appearance of recurrent osteosarcoma of the left femur and tibia in a 29-year-old woman with a history of osteosarcoma and chronic renal failure...

  17. Impingement heat sinks for air cooled high power electronic modules

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.S.; Holahan, M.F. [IBM Corp., Rochester, MN (United States)

    1995-12-31

    The subject of the present work is a parallel plate heat sink that is designed so that the air flow impinges at the fin tips and exhausts over the two open side faces. This type of design attempts to achieve an air flow direction that is substantially opposite to the heat flow direction within the fins so as to exploit the greater heat transfer effectiveness of counterflow heat exchange. A one dimensional model of the heat sink was developed with the assumption of air flow from the fin tips to the fin base. This simplified model was used to identify an initial heat sink geometry to cool a specific multichip module. Computational Fluid Dynamics models that account for the actual flow pattern within the heat sink were used to study a range of variations to the initial geometry and to identify the best geometry over the range examined. Experimental heat transfer and pressure drop data is reported for two heat sink prototypes. The test data is in good agreement with CFD predictions. Suitable correlations for the heat sink thermal resistance and pressure drop versus the air flow rate are developed. The developed heat sink demonstrated an area specific thermal resistance better than 8.7 C (W/cm{sup 2}).

  18. Shoulder muscle imbalance and subacromial impingement syndrome in overhead athletes.

    Science.gov (United States)

    Page, Phil

    2011-03-01

    Subacromial impingement is a frequent and painful condition among athletes, particularly those involved in overhead sports such as baseball and swimming. There are generally two types of subacromial impingement: structural and functional. While structural impingement is caused by a physical loss of area in the subacromial space due to bony growth or inflammation, functional impingement is a relative loss of subacromial space secondary to altered scapulohumeral mechanics resulting from glenohumeral instability and muscle imbalance. The purpose of this review is to describe the role of muscle imbalance in subacromial impingement in order to guide sports physical therapy evaluation and interventions.

  19. Vortex rings impinging on permeable boundaries

    Science.gov (United States)

    Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen

    2015-01-01

    Experiments with vortex rings impinging permeable and solid boundaries are presented in order to investigate the influence of permeability. Utilizing Particle Image Velocimetry, we compared the behaviour of a vortex ring impinging four different reticulated foams (with permeability k ˜ 26 - 85 × 10-8 m2) and a solid boundary. Results show how permeability affects the stretching phenomena of the vortex ring and the formation and evolution of the secondary vortex ring with opposite sign. Moreover, permeability also affects the macroscopic no-slip boundary condition found on the solid boundary, turning it into an apparent slip boundary condition for the most permeable boundary. The apparent slip-boundary condition and the flux exchange between the ambient fluid and the foam are jointly responsible for both the modified formation of the secondary vortex and changes on the vortex ring diameter increase.

  20. Laser-Induced Fluorescence Velocity Measurements in Supersonic Underexpanded Impinging Jets

    Science.gov (United States)

    Inman, Jennifer A.; Danehy, Paul M.; Barthel, Brett; Alderfer, David W.; Novak, Robert J.

    2010-01-01

    We report on an application of nitric oxide (NO) flow-tagging velocimetry to impinging underexpanded jet flows issuing from a Mach 2.6 nozzle. The technique reported herein utilizes a single laser, single camera system to obtain planar maps of the streamwise component of velocity. Whereas typical applications of this technique involve comparing two images acquired at different time delays, this application uses a single image and time delay. The technique extracts velocity by assuming that particular regions outside the jet flowfield have negligible velocity and may therefore serve as a stationary reference against which to measure motion of the jet flowfield. By taking the average of measurements made in 100 single-shot images for each flow condition, streamwise velocities of between -200 and +1,000 m/s with accuracies of between 15 and 50 m/s are reported within the jets. Velocity measurements are shown to explain otherwise seemingly anomalous impingement surface pressure measurements.

  1. Heat transfer due to impinging double free circular jets

    Directory of Open Access Journals (Sweden)

    Mohamed A. Teamah

    2015-09-01

    Full Text Available The heat transfer and fluid flow between a horizontal heated plate and impinging circular double jets were studied experimentally. The parameters investigated are the Reynolds number of each jet and jet-to-jet spacing. Experiments are carried out covering a range for Reynolds number from 7100 to 30,800 for each jet, the dimensionless jet-to-jet spacing from 22.73 to 90.1. During experimental phases, the right jet Reynolds number was higher than the left jet Reynolds number. The isothermal contours were plotted for different cases as well as the distribution of water film thickness over the heated plate. The results indicated that increasing the Reynolds number of one jet than the other increases both local and average Nusselt numbers. In addition, increasing the jet-to-jet spacing at the same Reynolds number increases the average Nusselt number.

  2. Turbulent heat transport and its anisotropy in an impinging jet

    Directory of Open Access Journals (Sweden)

    Petera Karel

    2015-01-01

    Full Text Available The turbulent heat transport is anisotropic in many cases as reported by several researchers. RANS-based turbulence models use the turbulent viscosity when expressing the turbulent heat flux in the energy balance (analogy of the Reynolds stresses in the momentum balance. The turbulent (eddy viscosity calculation comes from the Boussinesq analogy mainly and it represents just a scalar value, hence a possible anisotropy in the turbulent flow field cannot be simply transferred to the temperature field. The computational cost of a LES-based approach can be too prohibitive in complex cases, therefore simpler explicit algebraic heat flux models describing the turbulent heat flux in the time-averaged energy equation could be used to get more accurate CFD results. This paper compares several turbulence models for the case of a turbulent impinging jet and deals with a methodology of implementing a user-defined function describing the anisotropic turbulent heat flux in a CFD code.

  3. Large Eddy Simulation of Coherent Structure of Impinging Jet

    Institute of Scientific and Technical Information of China (English)

    Mingzhou YU; Lihua CHEN; Hanhui JIN; Jianren FAN

    2005-01-01

    @@ The flow field of a rectangular exit, semi-confined and submerged turbulent jet impinging orthogonally on a flat plate with Reynolds number 8500 was studied by large eddy simulation (LES). A dynamic sub-grid stress model has been used for the small scales of turbulence. The evolvements such as the forming, developing, moving,pairing and merging of the coherent structures of vortex in the whole regions were obtained. The results revealed that the primary vortex structures were generated periodically, which was the key factor to make the secondary vortices generate in the wall jet region. In addition, the eddy intensity of the primary vortices and the secondary vortices induced by the primary vortices along with the time were also analyzed.

  4. Study on the breakup length of circular impinging jet

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Circular impinging jet, which is widely used in accelerated control cooling (ACC) equipment to accelerate the cooling of hot rolled plates, is subject to breakup, and may result in undesirable cooling effect. Therefore, the jet breakup should be avoided as possible in industrial production. The objective of this study is to find the relation of the processing parameters of the ACC equipment versus the breakup length of jet with weaker turbulence. To obtain quantitative findings, not only relative experimental study but also numerical simulation was carried out. For a weaker turbulent water jet, the breakup length increases with the increase of jet diameter, as well as with the jet velocity; jet diameter has a significant effect on the breakup length for a certain flow rate when compared with jet velocity; finally a suggested correlation of the jet breakup length versus jet Weber number is presented in this study.

  5. Ischiofemoral impingement syndrome: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Adam D.; Subhawong, Ty K.; Jose, Jean; Tresley, Jonathan; Clifford, Paul D. [Jackson Memorial Hospital, Department of Diagnostic Radiology, Section of Musculoskeletal Imaging, Miami, FL (United States)

    2015-06-01

    The aims of this article are to review the imaging characteristics of ischiofemoral impingement (IFI), summarize measurement thresholds for radiologic diagnosis based on a meta-analysis of the literature and raise awareness among radiologists and clinicians of this entity. A PubMed search restricted to the English language containing the keywords ''ischiofemoral impingement'' and ''quadratus femoris MRI'' was performed, and citations in these articles were also used to identify a total of 27 studies discussing ischiofemoral impingement. After excluding case reports and non-representative studies, there were five remaining articles including 193 hip MRIs of IFI in 154 subjects (133 female, 21 male) and 135 asymptomatic control hip MRIs from 74 subjects (55 female, 19 male). Additionally, we performed a retrospective database search of pelvic and hip MRI reports from our institution including the terms ''quadratus femoris'' or ''ischiofemoral impingement'' from a 9-year period and 24 hip MRIs from 21 patients (18 female, 3 male) with IFI with 5 asymptomatic contralateral control hip MRIs identified. In all, 217 hip MRIs of IFI and 140 control cases were included. A meta-analysis of these hip MRIs was conducted to determine optimal thresholds of the ischiofemoral space (IFS) and quadratus femoris space (QFS) for identifying IFI. Cases of IFI showed significantly smaller IFS and QFS compared to controls (14.91 ± 4.8 versus 26.01 ± 7.98 and 9.57 ± 3.7 versus 15.97 ± 6.07, measured in mm, respectively, p < 0.0001 for both). Pooled analysis revealed that for IFS, using a cutoff of ≤15 mm yielded a sensitivity of 76.9 %, specificity of 81.0 % and overall accuracy of 78.3 %. For QFS, a cutoff of ≤ 10.0 mm resulted in 78.7 % sensitivity, 74.1 % specificity and 77.1 % overall accuracy. IFI is a potential cause of hip pain that can be accurately diagnosed with MRI in conjunction with

  6. A simple confined impingement jets mixer for flash nanoprecipitation.

    Science.gov (United States)

    Han, Jing; Zhu, Zhengxi; Qian, Haitao; Wohl, Adam R; Beaman, Charles J; Hoye, Thomas R; Macosko, Christopher W

    2012-10-01

    Johnson and Prud'homme (2003. AICHE J 49:2264-2282) introduced the confined impingement jets (CIJ) mixer to prepare nanoparticles loaded with hydrophobic compounds (e.g., drugs, inks, fragrances, or pheromones) via flash nanoprecipitation (FNP). We have modified the original CIJ design to allow hand operation, eliminating the need for a syringe pump, and we added a second antisolvent dilution stage. Impingement mixing requires equal flow momentum from two opposing jets, one containing the drug in organic solvent and the other containing an antisolvent, typically water. The subsequent dilution step in the new design allows rapid quenching with high antisolvent concentration that enhances nanoparticle stability. This new CIJ with dilution (CIJ-D) mixer is a simple, cheap, and efficient device to produce nanoparticles. We have made 55 nm diameter β-carotene nanoparticles using the CIJ-D mixer. They are stable and reproducible in terms of particle size and distribution. We have also compared the performance of our CIJ-D mixer with the vortex mixer, which can operate at unequal flow rates (Liu et al., 2008. Chem Eng Sci 63:2829-2842), to make β-carotene-containing particles over a series of turbulent conditions. On the basis of dynamic light scattering measurements, the new CIJ-D mixer produces stable particles of a size similar to the vortex mixer. Our CIJ-D design requires less volume and provides an easily operated and inexpensive tool to produce nanoparticles via FNP and to evaluate new nanoparticle formulation. Copyright © 2012 Wiley Periodicals, Inc.

  7. Editorial Commentary: Ligamentum Teres Tears and Femoroacetabular Impingement: Complex Coexistence of Impingement and Instability.

    Science.gov (United States)

    Larson, Christopher M

    2016-07-01

    In a large Level IV case series of 2,213 hip arthroscopies with the diagnosis of femoroacetabular impingement, the intraoperative status of the ligamentum teres (LT) was recorded as normal in 11%, frayed and/or partially torn in 88%, and completely torn in 1.5% of hips. Although specific physical examination maneuvers for detecting LT tears were not available early in the study period, thus limiting a detailed assessment of such tests, the authors identified that female gender, a lower lateral center edge angle, a higher Tonnis angle, and capsular laxity were all associated with complete LT tears. This study further supports the complex coexistence of impingement and instability.

  8. Two-Phase Flow in High-Heat-Flux Micro-Channel Heat Sink for Refrigeration Cooling Applications. Part 2: Low Temperature Hybrid Micro-Channel/Micro-Jet Impingement Cooling

    Science.gov (United States)

    2008-09-01

    pressure gradient ( Incropera , 1999). Watson (1964) used inviscid theory to determine Boiling and Two-Phase Flow Laboratory 23 thickness h of the wall jet...the pressure drop coefficient, f is inversely proportional to jet Reynolds ( Incropera , 1999) f = KRe,.,, (4.4) and K is fairly constant for the...both pool and forced convection boiling on submerged bodies in saturated liquids", Int. J. Heat Mass Transfer, Vol. 26, pp. 389-399. Incropera , F.P

  9. Ice growth and interface oscillation of water droplets impinged on a cooling surface

    Science.gov (United States)

    Hagiwara, Yoshimichi; Ishikawa, Shoji; Kimura, Ryota; Toyohara, Kazumasa

    2017-06-01

    We focused on the attenuation of air-water interface oscillation for impinged water droplets freezing on a cooling surface. We carried out not only experiments but also two-dimensional numerical simulation on the droplets using a Phase-field method and an immersed boundary method. The Reynolds number and Weber number were in the range of 35-129 and 1.6-22, respectively. The experimental and computational results showed that the height of the impinged droplets on the symmetrical axis started to oscillate as a result of the impact of the collision of droplets with the surfaces in all the cases that we investigated. The measured frequency of the oscillations in the case of the adiabatic droplets was equal to the frequency estimated from the equation for the capillary-gravity waves on sessile droplets (Temperton, 2013) [30]. The oscillations converged rapidly in all impinged water droplets that froze on the cooling surface. This is due partly to the growth of ice shells along the air-water interface and partly to decreases in water volume as a result of the ice growth mainly on the cooling surface. In addition, the thermal field was disturbed not only by the latent heat transfer but also by the upward component of recirculating flow induced by the droplet impingement.

  10. Modelling of jet-impingement cooling for power electronics

    OpenAIRE

    Rizvi, M.J.; Skuriat, R.; Tilford, Tim; Bailey, Christopher; Johnson, C. Mark; Lu, Hua

    2009-01-01

    The use of an innovative jet impingement cooling system in a power electronics application is investigated using numerical analysis. The jet impingement system, outlined by Skuriat et al, consists of a series of cells each containing an array of holes. Cooling fluid is forced through the device, forming an array of impingement jets. The jets are arranged in a manner, which induces a high degree of mixing in the interface boundary layer. This increase in turbulent mixing is intended to induce ...

  11. Meralgia paresthetica and femoral acetabular impingement: a possible association.

    Science.gov (United States)

    Ahmed, Aiesha

    2010-12-11

    Meralgia paresthetica consists of pain and dysesthesia in the anterolateral thigh. Etiology is divided into spontaneous and iatrogenic causes. To my knowledge this has never been attributed to femoral acetabular impingement. This case highlights the presence of lateral femoral cutaneous neuropathy in the setting of femoral acetabular impingement syndrome thus raising the possibility of an association. Femoral acetabular impingement; Lateral femoral cutaneous nerve; Dysesthesia; Nerve conduction studies.

  12. Impingement capability of high-pressure submerged water jet:Numerical prediction and experimental verification

    Institute of Scientific and Technical Information of China (English)

    刘海霞; 邵启明; 康灿; 龚辰

    2015-01-01

    At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity.

  13. Xanthogranulomatous cholecystitis mimicking gallbladder cancer.

    Science.gov (United States)

    Ewelukwa, Ofor; Ali, Omair; Akram, Salma

    2014-05-08

    Xanthogranulomatous cholecystitis (XGC) is a benign, uncommon variant of chronic cholecystitis characterised by focal or diffuse destructive inflammatory process of the gallbladder (GB). Macroscopically, it appears like yellowish tumour-like masses in the wall of the GB. This article reports on a 74-year-old woman with XGC mimicking GB cancer.

  14. Anterior iliopsoas impingement after total hip arthroplasty.

    Science.gov (United States)

    Trousdale, R T; Cabanela, M E; Berry, D J

    1995-08-01

    Pain after total hip arthroplasty (THA) can be caused by a multitude of conditions, including infection, aseptic loosening, heterotopic ossification, and referred pain. It is also recognized that soft tissue inflammation about the hip, such as trochanteric bursitis, can lead to hip pain after THA. Two cases of persistent iliopsoas tendinitis following THA are reported, which are believed to be caused by psoas tendon impingement against a malpositioned, uncemented, metal-backed acetabular component. The authors are unaware of previous reports of this problem, and suggest that the problem be considered in the differential diagnosis of groin pain following THA.

  15. SCALE EFFECT OF IMPINGING PRESSURE CAUSED BY SUBMERGED JET

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhong; XU Wei-lin; WANG Wei; LIU Shan-jun; DONG Jian-wei

    2005-01-01

    The characteristics of the impinging pressure at the jet equipment where the maximum jet velocity can reach 50m/s were studied. By comparing the impinging pressure with the one measured at the low velocity conditions, two conclusions of the scale effect are drawn: firstly, the velocity attenuation degree is smaller than that of low-velocity jet, and secondly, the relative impinging width is narrower than that of low-velocity jet. The reasons of the scale effect of the impinging pressure were elucidated through numerical simulation.

  16. Clinical or radiological diagnosis of impingement; Klinische oder radiologische Diagnose des Impingements

    Energy Technology Data Exchange (ETDEWEB)

    Kloth, J.K.; Weber, M.A. [Universitaetsklinikum Heidelberg, Klinik fuer diagnostische und interventionelle Radiologie, Heidelberg (Germany); Zeifang, F. [Universitaetsklinikum Heidelberg, Zentrum fuer Orthopaedie, Unfallchirurgie und Paraplegiologie, Heidelberg (Germany)

    2015-03-01

    Shoulder impingement syndrome is a clinically common entity involving trapping of tendons or bursa with typical clinical findings. Important radiological procedures are ultrasound, magnetic resonance imaging (MRI) and MR arthrography. Projection radiography and computed tomography (CT) are ideal to identify bony changes and CT arthrography also serves as an alternative method in cases of contraindications for MRI. These modalities support the clinically suspected diagnosis of impingement syndrome and may identify its cause in primary diagnosis. In addition, effects of impingement are determined by imaging. Therapy decisions are based on a synopsis of radiological and clinical findings. The sensitivity and specificity of these imaging modalities with regard to the diagnostics of a clinically evident impingement syndrome are given in this review article. Orthopedic and trauma surgeons express the suspicion of an impingement syndrome based on patient history and physical examination and radiologists confirm structural changes and damage of intra-articular structures using dedicated imaging techniques. (orig.) [German] Das Impingementsyndrom der Schulter ist ein haeufiges Einklemmungsphaenomen von Sehnen oder Bursen mit typischem klinischem Befund. Wichtige radiologische Verfahren sind Sonographie, MRT und MR-Arthrographie. Projektionsradiographie und CT sind ideal, um knoecherne Veraenderungen aufzuzeigen. Die CT-Arthrographie dient zudem als Ersatzverfahren bei Kontraindikationen fuer die MRT. Diese genannten Modalitaeten koennen in der Primaerdiagnostik die Diagnose eines Impingementsyndroms stuetzen und dessen Ursache aufzeigen. Zudem werden bildgebend Folgen der Einklemmung festgestellt und in Zusammenschau von klinischer Symptomatik und radiologischem Befund Therapieentscheidungen getroffen. Die Sensitivitaet und Spezifitaet der zuvor genannten bildgebenden Verfahren in Bezug auf die diagnostische Aufarbeitung einer klinisch evidenten Impingementsymptomatik

  17. Modelling of soft impingement during solidification

    Indian Academy of Sciences (India)

    K T Kashyap; S Yamdagni

    2007-08-01

    It has been well established that spheroidal grain morphology in the microstructure forms during stir casting (rheocasting) and grain refinement of magnesium alloys by zirconium addition. This curious microstructure has been of interest both commercially from enhanced mechanical properties and also scientific interest in explaining the mechanism of spheroidal grain formation. Vogel and Doherty proposed a model describing the fracturing of dendrite arms during stir casting to produce a high density of nuclei which they presume to give rise to spheroidal grains. They proposed that there is soft impingement of diffusion fields of neighbouring nuclei, which reduces the concentration gradient ahead of the planar solid and liquid interface, which in turn negates shape instability. In this paper, the Vogel and Doherty model is pursued by quantitative modeling of soft impingement problem and related to shape instability by constitutional supercooling theory. This analysis correctly predicts the spheroidal grain formation during stir casting or rheocasting. This model can also be used to explain the grain refinement of magnesium alloys by zirconium addition wherein spheroidal grains are formed.

  18. Oil-in-water emulsification using confined impinging jets.

    Science.gov (United States)

    Siddiqui, Shad W; Norton, Ian T

    2012-07-01

    A confined impinging jet mixing device has been used to investigate the continuous sunflower oil/water emulsification process under turbulent flow conditions with oil contents between 5% (v/v) and 10% (v/v). Various emulsifiers (Tween20, Span80, Whey Protein, Lecithin and Sodium Dodecylsulphate) varying in molecular weights have been studied. Mean droplet sizes varied with the emulsifiers used and smallest droplets were obtained under fully turbulent flow regime, i.e. at the highest jet flow rate and highest jet Reynolds Number conditions. Sodium Dodecylsulfate (SDS) produced droplets in the range of 3.8 μm while 6 μm droplets were obtained with Whey Protein. Similar droplet sizes were obtained under fully turbulent flow conditions (610 mL/min; Reynolds Number=13,000) for oil content varying between 5% (v/v) and 10% (v/v). To investigate the smallest droplet size possible in the device, the emulsion was passed through the geometry multiple times. Multi-pass emulsification resulted in reduction in droplet size indicating that longer residence in the flow field under high shear condition allowed for breakage of droplets as well as the time for the emulsifier to stabilize the newly formed droplets, decreasing the impact of coalescence. This was confirmed by timescale analysis of the involved process steps for the droplet data obtained via experiments. Dependence of mean droplet size on the o/w interfacial tension and peak energy dissipation was also investigated. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Multicystic Hepatocarcinoma Mimicking Liver Abscess

    Directory of Open Access Journals (Sweden)

    Evangelos Falidas

    2013-01-01

    Full Text Available The diagnosis of hepatocellular carcinoma (HCC became easier in relation to the improved radiological examinations; however, the neoplasm may occur under atypical presentations mimicking other benign or malignant processes. Multicystic HCC mimicking a liver abscess associated with septic-type fever and leukocytosis is rare, has a poor prognosis, and poses diagnostic and therapeutic dilemmas. We present the case of an 80-year-old patient, who presented with fever, leukocytosis, and large cystic masses involving right and left lobes of the liver initially considered abscesses and finally diagnosed as HCC after open drainage and liver biopsy. Although the patient died on the tenth postoperative day due to pulmonary oedema, the authors emphasize the high index of suspicion needed in the diagnosis of this unusual presentation of HCC.

  20. Hypercalcaemia Mimicking STEMI on Electrocardiography

    Directory of Open Access Journals (Sweden)

    Joseph Donovan

    2010-01-01

    Full Text Available Acute coronary syndrome is a common cause of presentation to hospital. ST segment elevation on an electrocardiogram (ECG is likely to be cardiac in origin, but in low-risk patients other causes must be ruled out. We describe a case of a man with hypercalcaemia, no evidence of cardiac disease, and ECG changes mimicking acute myocardial infarction. These ECG changes resolved after treatment of the hypercalcaemia.

  1. Cooling Performance of an Impingement Cooling Device Combined with Pins

    Institute of Scientific and Technical Information of China (English)

    Dongliang QUAN; Songling LIU; Jianghai LI; Gaowen LIU

    2005-01-01

    Experimental study and one dimensional model analysis were conducted to investigate cooling performance of an integrated impingement and pin fin cooling device. A typical configuration specimen was made and tested in a large scale low speed closed-looped wind tunnel. Detailed two-dimensional contour maps of the temperature and cooling effectiveness were obtained for different pressure ratios and therefore different coolant flow-rates through the tested specimen. The experimental results showed that very high cooling effectiveness can be achieved by this cooling device with relatively small amount of coolant flow. Based on the theory of transpiration cooling in porous material, a one dimensional heat transfer model was established to analyze the effect of various parameters on cooling effectiveness. It was found from this model that the variation of heat transfer on the gas side, including heat transfer coefficient and film cooling effectiveness, of the specimen created much more effect on its cooling effectiveness than that of the coolant side. The predictions of the one-dimensional mode were compared and agreed well with the experimental data.

  2. Rehabilitation for Subacromial Impingement Starts at the Scapula

    Directory of Open Access Journals (Sweden)

    Peggy A. Houglum

    2013-12-01

    Full Text Available Subacromial impingement, especially secondary subacromial impingement, is a common malady of athletes and non-athletes alike. Although several pathologies may lead to impingement, they all relate back to poor posture. Over time, postural changes increase stress to soft tissue structures to change both alignment and performance. Injury results as low-level stresses impact weakening tissues to the point of overload. Crucial to effective treatment of secondary subacromial impingement is the identification and correction of all causes. Basic to successful treatment is correction of posture, including scapular posture and muscles which control, stabilize, and move the scapula. An evidence-based approach to not only identifying the causes but also creating a treatment regimen to effectively resolve secondary subacromial impingement is presented.

  3. Technique of Arthroscopic Treatment of Impingement After Total Ankle Arthroplasty.

    Science.gov (United States)

    Gross, Christopher E; Neumann, Julie A; Godin, Jonathan A; DeOrio, James K

    2016-04-01

    Rates of medial and/or lateral gutter impingement after total ankle replacement are not insignificant. If impingement should occur, it typically arises an average of 17 months after total ankle replacement. Our patient underwent treatment for right ankle medial gutter bony impingement with arthroscopic debridement 5 years after her initial total ankle replacement. Standard anteromedial and anterolateral portals and a 30° 2.7-mm-diameter arthroscope were used. An aggressive soft-tissue and bony resection was performed using a combination of curettes, a 3.5-mm shaver, a 5.5-mm unsheathed burr, a drill, and a radiofrequency ablator. This case shows that arthroscopic treatment is an effective and potentially advantageous alternative to open treatment of impingement after total ankle replacement. In addition, symptoms of impingement often improve in a short amount of time after arthroscopic debridement of the medial and/or lateral gutter.

  4. Experimental investigation of influence of Reynolds number on synthetic jet vortex rings impinging onto a solid wall

    Science.gov (United States)

    Xu, Yang; He, GuoSheng; Kulkarni, Varun; Wang, JinJun

    2017-01-01

    Time-resolved particle image velocimetry was employed to study the effect of Reynolds number ( Re sj) on synthetic jet vortex rings impinging onto a solid wall. Four Reynolds numbers ranging from 166 to 664 were investigated for comparison while other parameters were kept constant. It is found that the Reynolds number has a significant impact on the spatial evolution of near-wall vortical structures of the impinging synthetic jet. Velocity triple decomposition reveals that periodic Reynolds shear stresses produced by both impinging and secondary vortex rings agree well with a four-quadrant-type distribution rule, and the random velocity fluctuations are strengthened as Re sj increases. For radial wall jet, radial velocity profiles exhibit a self-similar behavior for all Re sj, and this self-similar profile gradually deviates from the laminar solution as Re sj is increased. In particular, the self-similar profile for low Re sj (166) coincides with the laminar solution indicating that periodic velocity fluctuations produced by vortex rings have little effect on the velocity profile of the laminar wall jet. This also provides evidence that the impinging synthetic jet is more effective in mixing than the continuous jet for the laminar flow. For the high Re sj, the mean skin friction coefficient has a slower decay rate after reaching peak, and the radial momentum flux has a higher value at locations far away from the impingement region, both of these can be attributed to the enhanced random fluctuations.

  5. Electron impinging on metallic thin film targets

    Energy Technology Data Exchange (ETDEWEB)

    Rouabah, Z. [Laboratoire de Physique Moleculaire et des Collisions, ICPMB (FR CNRS 2843), Institut de Physique, Universite Paul Verlaine-Metz, Metz Cedex 3 (France); Laboratoire Materiaux et Systemes Electroniques, Centre Universitaire de Bordj-Bou-Arreridj, El-Anasser, 34265 Bordj-Bou-Arreridj (Algeria); Bouarissa, N., E-mail: N_Bouarissa@yahoo.fr [Department of Physics, Faculty of Science, King Khalid University, Abha, P.O.Box 9004 (Saudi Arabia); Champion, C. [Laboratoire de Physique Moleculaire et des Collisions, ICPMB (FR CNRS 2843), Institut de Physique, Universite Paul Verlaine-Metz, Metz Cedex 3 (France)

    2010-03-15

    Based on the Vicanek and Urbassek theory [M. Vicanek, H.M. Urbassek, Phys. Rev. B 44 (1991) 7234] combined to a home-made Monte Carlo simulation, the present work deals with backscattering coefficients, mean penetration depths and stopping profiles for 1-4 keV electrons normally incident impinging on Al and Cu thin film targets. The cross-sections used to describe the electron transport are calculated via the appropriate analytical expression given by Jablonski [A. Jablonski, Phys. Rev. B 58 (1998) 16470] whose new improved version has been recently given [Z. Rouabah, N. Bouarissa, C. Champion, N. Bouaouadja, Appl. Surf. Sci. 255 (2009) 6217]. The behavior of the backscattering coefficient, mean penetration depth and stopping profiles versus the metallic film thickness at the nanometric scale and beyond is here analyzed and discussed.

  6. PIV measurements of isothermal plane turbulent impinging jets at moderate Reynolds numbers

    Science.gov (United States)

    Khayrullina, A.; van Hooff, T.; Blocken, B.; van Heijst, G. J. F.

    2017-04-01

    This paper contains a detailed experimental analysis of an isothermal plane turbulent impinging jet (PTIJ) for two jet widths at moderate Reynolds numbers (7200-13,500) issued on a horizontal plane at fixed relative distances equal to 22.5 and 45 jet widths. The available literature on such flows is scarce. Previous studies on plane turbulent jets mainly focused on free jets, while most studies on impinging jets focused on the heat transfer between the jet and an impingement plane, disregarding jet development. The present study focuses on isothermal PTIJs at moderate Reynolds numbers characteristic of air curtains. Flow visualisations with fluorescent dye and 2D particle image velocimetry (PIV) measurements have been performed. A comparison is made with previous studies of isothermal free turbulent jets at moderate Reynolds numbers. Mean and instantaneous velocity and vorticity, turbulence intensity, and Reynolds shear stress are analysed. The jet issued from the nozzle with higher aspect ratio shows more intensive entrainment and a faster decay of the centreline velocity compared to the jet of lower aspect ratio for the same value of jet Reynolds number. The profiles of centreline and cross-jet velocity and turbulence intensity show that the PTIJs behave as a free plane turbulent jet until 70-75% of the total jet height. Alongside the information obtained on the jet dynamics, the data will be useful for the validation of numerical simulations.

  7. Impinging Water Droplets on Inclined Glass Surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, Kenneth Miguel; Lance, Blake; Ho, Clifford K.

    2017-09-01

    Multiphase computational models and tests of falling water droplets on inclined glass surfaces were developed to investigate the physics of impingement and potential of these droplets to self-clean glass surfaces for photovoltaic modules and heliostats. A multiphase volume-of-fluid model was developed in ANSYS Fluent to simulate the impinging droplets. The simulations considered different droplet sizes (1 mm and 3 mm), tilt angles (0deg, 10deg, and 45deg), droplet velocities (1 m/s and 3 m/s), and wetting characteristics (wetting=47deg contact angle and non-wetting = 93deg contact angle). Results showed that the spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) decreased with increasing inclination angle due to the reduced normal force on the surface. The hydrophilic surface yielded greater spread factors than the hydrophobic surface in all cases. With regard to impact forces, the greater surface tilt angles yielded lower normal forces, but higher shear forces. Experiments showed that the experimentally observed spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) was significantly larger than the simulated spread factor. Observed spread factors were on the order of 5 - 6 for droplet velocities of %7E3 m/s, whereas the simulated spread factors were on the order of 2. Droplets were observed to be mobile following impact only for the cases with 45deg tilt angle, which matched the simulations. An interesting phenomenon that was observed was that shortly after being released from the nozzle, the water droplet oscillated (like a trampoline) due to the "snapback" caused by the surface tension of the water droplet being released from the nozzle. This oscillation impacted the velocity immediately after the release. Future work should evaluate the impact of parameters such as tilt angle and surface wettability on the impact of particle/soiling uptake and removal to investigate ways that

  8. Dynamics of fine particles during impingement of jets on a body with a needle

    Science.gov (United States)

    Alkhimov*, A. P.; Bedarev, I. A.; Fedorov, A. V.

    2013-07-01

    Numerical simulation of the impingement of a jet of a two-phase mixture of a gas with submicron metal particles on an obstacle with a needle located in front of it is carried out. The structure of a separated flow formed on impingement of a supersonic jet on a body with a needle has been studied. A comparison of various approximations for the law of resistance of spherical particles is made. It is shown that particles whose size exceeds 5 μm practically have a rectilinear trajectory and velocity sufficient for cold gas-dynamical deposition, whereas particles of diameter less than 0.2 μm envelope the separation zone being formed near the needle, and their velocity is much smaller than the critical one.

  9. Vortex dynamics and wall shear stress behaviour associated with an elliptic jet impinging upon a flat plate

    Science.gov (United States)

    Long, J.; New, T. H.

    2016-07-01

    Vortical structures and dynamics of a Re h = 2100 elliptic jet impinging upon a flat plate were studied at H/ d h = 1, 2 and 4 jet-to-plate separation distances. Flow investigations were conducted along both its major and minor planes using laser-induced fluorescence and digital particle image velocimetry techniques. Results show that the impingement process along the major plane largely consists of primary jet ring-vortex and wall-separated secondary vortex formations, where they subsequently separate from the flat plate at smaller H/ d h = 1 and 2 separation distances. Key vortex formation locations occur closer to the impingement point as the separation distance increases. Interestingly, braid vortices and rib structures begin to take part in the impingement process at H/ d h = 4 and wave instabilities dominate the flow field. In contrast, significantly more coherent primary and secondary vortices with physically larger vortex core sizes and higher vortex strengths are observed along the minor plane, with no signs of braid vortices and rib structures. Lastly, influences of these different flow dynamics on the major and minor plane instantaneous and mean skin friction coefficient levels are investigated to shed light on the effects of separation distance on the wall shear stress distributions.

  10. Advanced Liquid Cooling for a Traction Drive Inverter Using Jet Impingement and Microfinned Enhanced Surfaces: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S. K.; Narumanchi, S.; Mihalic, M.; Moreno, G.; Bennion, K.; Jeffers, J.

    2014-08-01

    Jet impingement on plain and micro-finned enhanced surfaces was compared to a traditional channel flow configuration. The jets provide localized cooling to areas heated by the insulated-gate bipolar transistor and diode devices. Enhanced microfinned surfaces increase surface area and thermal performance. Using lighter materials and designing the fluid path to manage pressure losses increases overall performance while reducing weight, volume, and cost. Powering four diodes in the center power module of the inverter and computational fluid dynamics (CFD) modeling was used to characterize the baseline as well as jet-impingement-based heat exchangers. CFD modeling showed the thermal performance improvements should hold for a fully powered inverter. Increased thermal performance was observed for the jet-impingement configurations when tested at full inverter power (40 to 100 kW output power) on a dynamometer. The reliability of the jets and enhanced surfaces over time was also investigated. Experimentally, the junction-to- coolant thermal resistance was reduced by up to 12.5% for jet impingement on enhanced surfaces s compared to the baseline channel flow configuration. Base plate-to-coolant (convective) resistance was reduced by up to 37.0% for the jet-based configuration compared to the baseline, suggesting that while improvements to the cooling side reduce overall resistance, reducing the passive stack resistance may contribute to lowering overall junction-to-coolant resistance. Full inverter power testing showed reduced thermal resistance from the middle of the module baseplate to coolant of up to 16.5%. Between the improvement in thermal performance and pumping power, the coefficient of performance improved by up to 13% for the jet-based configuration.

  11. Conformal mapping technique for two-dimensional porous media and jet impingement heat transfer

    Science.gov (United States)

    Siegel, R.

    1974-01-01

    Transpiration cooling and liquid metals both provide highly effective heat transfer. Using Darcy's law in porous media and the inviscid approximation for liquid metals, the local fluid velocity in these flows equals the gradient of a potential. The energy equation and flow region are simplified when transformed into potential plane coordinates. In these coordinates, the present problems are reduced to heat conduction solutions which are mapped into the physical geometry. Results are obtained for a porous region with simultaneously prescribed surface temperature and heat flux, heat transfer in a two-dimensional porous bed, and heat transfer for two liquid metal slot jets impinging on a heated plate.

  12. Heat transfer from impinging jets to a flat plate with conical and ring protuberances

    Science.gov (United States)

    Hrycak, P.

    1984-01-01

    An experimental investigation of heat transfer from round jets, impinging normally on a flat plate with exchangeable, heat transfer enhancing protuberances, has been carried out, and the pertinent literature surveyed, for Reynolds numbers ranging from 14,000 to 67,000, and nozzle diameters from 3.18 to 9.52 mm. The experimental data at the stagnation point indicated laminar flow, and a significant enhancement of heat transfer there, due to the introduction of the spike protuberance; the ring protuberance reduced the local heat flux somewhat. Data have also been correlated by means of dimensional analysis and compared with the conical flow theory.

  13. Experimental Study of Impinging Jets Flow-Fields

    Science.gov (United States)

    2016-07-27

    employment in industry in Delaware . He has been receiving academic credit for the work he has been doing on this project. 15 9. Publications...PERSON a. REPORT b. ABSTRACT c. THIS PAGE 19b. TELEPHONE NUMBER (include area code) Standard Form 298 (Re . 8-98) v Prescribed by ANSI Std . Z39.18

  14. Decidualized Ovarian Mass Mimicking Malignancy

    Directory of Open Access Journals (Sweden)

    Lufee Wong

    2015-01-01

    Full Text Available Deciduosis classically occurs in the context of known endometriosis in the pelvis, most commonly in the ovaries, but also in the peritoneum. However, ovarian deciduosis outside the context of endometriosis is rare and makes diagnosis difficult, especially as the sonographic appearance suggests a malignant process. We report a case of decidualized ovarian mass in a patient without prior history of endometriosis that mimicked an ovarian malignancy. MRI may be a useful imaging modality to monitor these lesions and guide management. Consultation with a multidisciplinary team accustomed to such conditions will help to tailor the management to each individual.

  15. Experimental and Numerical Study of Twin Underexpanded Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru Yaga; Minoru Okano; Masumi Tamashiro; Kenyu Oyakawa

    2003-01-01

    In this paper, the dual underexpanded impinging jets are experimentally and numerically studied. The experiments were performed by measuring the unsteady and averaged wall static pressures and by visualizing density fields using schlieren method. Numerical calculations were also conducted by solving unsteady three dimensional compressible Navier-Stokes equations with Baldwin-Lomax turbulence model. The main parameters for the dual jets are the non-dimensional distance between the two nozzle centers H/D covering 1.5, 2.0, the nozzle to plate separation L/D 2.0, 3.0,4.0 and 5.0 and the pressure ratio defined by Po/Pb 1.0~6.0, where D is the diameter of each nozzle exit, Po the stagnation pressure and Pb the back pressure. It is found that the agreement between the experiments and the calculations is good. The fountain flow at the middle of the two jets is observed both in the experiments and the calculation. According to FFT analysis of the experiments for the twin jets,relatively low frequency (up to 5 kHz) is dominant for H/D =1.5, L/D =2.0 and pressure ratio Po/Pb =3.0 and 5.0,which is confirmed by the experiments.

  16. Biological evaluation of devices used for reducing entrainment and impingement losses at thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Cada, G.F.; Szluha, A.T.

    1978-01-01

    A preliminary survey of fish protection devices either in use or proposed for water intake structures was conducted for the purpose of assessing their potential for reducing impingement and entrainment. All the designs examined can be divided into two basic categories: behavioral screening systems and physical screening systems. The behavioral screening devices rely upon the ability of fish to sense artificial stimuli and respond by swimming away from hazardous areas. These systems are of little or no value in protecting planktonic fish eggs, larvae, and disoriented, heat-shocked, or lethargic adult fishes. Many of the physical screening devices, on the other hand, require the impingement of organisms against a screen before they can be removed from the intake system, thus subjecting survival. Some of the designs incorporate both behavioral and physical sceening concepts. Six devices were selected for further consideration based on their potential or demonstrated effectiveness in reducing impingement and entrainment losses at a variety of intake situations. The structures evaluated were modified vertical traveling screens, louvers, angled vertical traveling screens, horizontal traveling screens, center-flow screens, and wedge-wire screens. Since some of these intake structures represent new concepts, few laboratory or in situ biological studies have been carried out. For others, actual reductions in fish losses have been demonstrated. The design features and status of biological testing is discussed for each device, and an evaluation of their fish protection potential is presented.

  17. Enhancement of Heat Transfer with Pool and Spray Impingement Boiling on Microporous and Nanowire Surface Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Thiagarajan, S. J.; Wang, W.; Yang, R.; Narumanchi, S.; King, C.

    2010-09-01

    The DOE National Renewable Energy Laboratory (NREL) is leading a national effort to develop next-generation cooling technologies for hybrid vehicle electronics. The goal is to reduce the size, weight, and cost of power electronic modules that convert direct current from batteries to alternating current for the motor, and vice versa. Aggressive thermal management techniques help to increase power density and reduce weight and volume, while keeping chip temperatures within acceptable limits. The viability of aggressive cooling schemes such as spray and jet impingement in conjunction with enhanced surfaces is being explored. Here, we present results from a series of experiments with pool and spray boiling on enhanced surfaces, such as a microporous layer of copper and copper nanowires, using HFE-7100 as the working fluid. Spray impingement on the microporous coated surface showed an enhancement of 100%-300% in the heat transfer coefficient at a given wall superheat with respect to spray impingement on a plain surface under similar operating conditions. Critical heat flux also increased by 7%-20%, depending on flow rates.

  18. Effect of controlling parameters on heat transfer during spray impingement cooling of steel plate

    Directory of Open Access Journals (Sweden)

    Purna C. Mishra

    2013-09-01

    Full Text Available The heat transfer characteristics of air-water spray impingement cooling of stationary steel plate was experimentally investigated. Experiments were conducted on an electrically heated flat stationary steel plate of dimension 120 mm x 120 mm x 4 mm. The controlling parameters taken during the experiments were airwater pressures, water flow rate, nozzle tip to target distance and mass impingement density. The effects of the controlling parameters on the cooling rates were critically examined during spray impingement cooling. Air assisted DM water was used as the quenchant media in the work. The cooling rates were calculated from the time dependent temperature profiles were recorded by NI-cRIO DAS at the desired locations of the bottom surface of the plate embedded with K-type thermocouples. By using MS-EXCEL the effects of these cooling rate parameters were analysed The results obtained in the study confirmed the higher efficiency of the spray cooling system and the cooling strategy was found advantageous over the conventional cooling methods in the present steel industries

  19. Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2

    Science.gov (United States)

    Wang, Xiao-Yen; Lumpkin, Forrest E., III; Gati, Frank; Yuko, James R.; Motil, Brian J.

    2009-01-01

    The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module was performed using MSC Patran/Pthermal. The obtained temperature results showed that thermal protection is necessary because of significant heating from the plume.

  20. Experimental study of slot jet impingement heat transfer on a wedge-shaped surface

    Science.gov (United States)

    Rahimi, Mostafa; Irani, Mohammad

    2012-12-01

    An experimental investigation was conducted to study the convective heat transfer rate from a wedge-shaped surface to a rectangular subsonic air jet impinging onto the apex of the wedge. The jet Reynolds number, nozzle-to-surface distance and the wedge angle were considered as the main parameters. Jet Reynolds number was ranged from 5,000 to 20,000 and two dimensionless nozzle-to-surface distances h/w = 4 and 10 were examined. The apex angle of the wedge ranged from 30° to 180° where the latter case corresponds with that of a flat surface. Velocity profile and turbulence intensity were provided for free jet flow using hot wire anemometer. Local and average Nusselt numbers on the impinged surface are presented for all the configurations. Based on the results presented, the local Nusselt number at the stagnation region increases as the wedge angle is decreased but, it then decreases over the remaining area of the impinged surface. Average Nusselt number over the whole surface is maximum when the wedge angle is 180° (i.e. plane surface) for any jet and nozzle-to-surface configuration.

  1. Unusual Bilateral Rim Fracture in Femoroacetabular Impingement

    Directory of Open Access Journals (Sweden)

    Claudio Rafols

    2015-01-01

    Full Text Available This is a report of one case of bilateral acetabular rim fracture in association with femoroacetabular impingement (FAI, which was treated with a hip arthroscopic procedure, performing a partial resection, a labral reinsertion, and a subsequential internal fixation with cannulated screws. Up to date, there are in the literature only two reports of rim fracture and “os acetabuli” in association with FAI. In the case we present, the pincer and cam resection were performed without complications; the technique used was published previously. With this technique the head of the screw lays hidden by the reattached labrum. We removed partially the fractured rim fragment and the internal fixation of the remaining portion was achieved with a screw. In the event of a complete resection of the fragment, it would have ended with a LCE angle of 18° and a high probability of hip instability. We believe that this bilateral case helps establish the efficacy and reproducibility of the technique described by Larson.

  2. Low EUV Luminosities Impinging on Protoplanetary Disks

    CERN Document Server

    Pascucci, I; Gorti, U; Hollenbach, D; Hendler, N P; Brooks, K J; Contreras, Y

    2014-01-01

    The amount of high-energy stellar radiation reaching the surface of protoplanetary disks is essential to determine their chemistry and physical evolution. Here, we use millimetric and centimetric radio data to constrain the EUV luminosity impinging on 14 disks around young (~2-10Myr) sun-like stars. For each object we identify the long-wavelength emission in excess to the dust thermal emission, attribute that to free-free disk emission, and thereby compute an upper limit to the EUV reaching the disk. We find upper limits lower than 10$^{42}$ photons/s for all sources without jets and lower than $5 \\times 10^{40}$ photons/s for the three older sources in our sample. These latter values are low for EUV-driven photoevaporation alone to clear out protoplanetary material in the timescale inferred by observations. In addition, our EUV upper limits are too low to reproduce the [NeII] 12.81 micron luminosities from three disks with slow [NeII]-detected winds. This indicates that the [NeII] line in these sources prima...

  3. Diagnostic imaging of shoulder impingement; Bildgebende Diagnostik des Schultergelenkes bei Impingement

    Energy Technology Data Exchange (ETDEWEB)

    Merl, T. [Technische Univ. Muenchen (Germany). Inst. fuer Roentgendiagnostik; Weinhardt, H. [Klinikum Rechts der Isar, Muenchen (Germany). Klinik und Poliklinik fuer Orthopaedie; Oettl, G. [Klinikum Rechts der Isar, Muenchen (Germany). Klinik und Poliklinik fuer Orthopaedie; Lenz, M. [Technische Univ. Muenchen (Germany). Inst. fuer Roentgendiagnostik; Riel, K.A. [Klinikum Rechts der Isar, Muenchen (Germany). Klinik und Poliklinik fuer Orthopaedie

    1996-01-01

    Magnetic resonance imaging is a method that has been advancing in the last few years to the modality of choice for diagnostic evaluation of the bone joints, as the method is capable of imaging not only the ossous but also the soft tissue components of the joint. MRI likewise has become an accepted method for diagnostic evaluation of syndromes of the shoulder, with high diagnostic accuracy in detecting rotator cuff lesions, or as an efficient MRI arthrography for evaluation of the instability or lesions of the labrocapsular complex. In the evaluation of early stages of shoulder impingement, the conventional MRI technique as a static technique yields indirect signs which in many cases do not provide the diagnostic certainty required in order to do justice to the functional nature of the syndrome. In these cases, functional MRI for imaging of the arm in abducted position and in rotational movement may offer a chance to early detect impingement and thus identify patients who will profit from treatment at an early stage. [Deutsch] Die Magnetresonanztomographie hat sich in den letzten Jahren zur Methode der Wahl in der Diagnostik der Gelenke entwickelt, sie erlaubt neben der Abbildung aller knoechernen auch die Abbildung aller Weichteilelemente eines Gelenkes. Auch in der Diagnostik der Schultergelenkserkrankungen besitzt die Magnetresonanztomographie einen festen Stellenwert mit hoher diagnostischer Treffsicherheit in der Beurteilung der Rotatorenmanschette, als MR-Arthrographie auch in der Beurteilung der Instabilitaet bzw von Laesionen des labrokapsulaeren Komplexes. In der Bewertung frueher Stadien des Impingement ist die klassische Magnetresonanztomographie als statische Methode auf indirekte Zeichen angewiesen, die in vielen Faellen nicht ausreichende Sicherheit bieten und dem funktionellen Charakter des Krankheitsbildes nicht ausreichend Rechnung tragen. Hier koennte die funktionelle Magnetresonanztomographie unter Abbildung des Arms in Abduktion und Rotation eine

  4. 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.

  5. Talar Osteochondroma Fracture Presenting as Posterior Ankle Impingement.

    Science.gov (United States)

    Ercin, Ersin; Bilgili, Mustafa Gokhan; Gamsizkan, Mehmet; Avsar, Serdar

    2016-05-01

    Osteochondromas are the most common benign bone tumors. They are usually asymptomatic and found incidentally. When symptomatic, the symptoms are usually due to its location and size. Fracture of an osteochondroma presenting as posterior ankle impingement is a rare condition. We describe a 22-year-old man with solitary exostosis who presented with a posterior ankle mass and posterior ankle impingement with 2 years of follow-up. Surgical intervention was the treatment of choice in this patient, and histologic examination revealed a benign osteochondroma. Osteochondromas found in the posterior aspect of the talus can be complicated by fracture due to persistent motion of the ankle. Talar osteochondroma should be included in the differential diagnosis of posterior ankle impingement causes. Posterior talar osteochondromas, especially when a stalk is present, should be treated surgically before it is more complicated by a fracture and posterior ankle impingement.

  6. An ideal blood mimicking fluid for doppler ultrasound phantoms.

    Science.gov (United States)

    Samavat, H; Evans, J A

    2006-10-01

    In order to investigate the problems of detecting tumours by ultrasound it is very important to have a portable Doppler flow test object to use as a standardising tool. The flow Doppler test objects are intended to mimic the flow in human arteries. To make the test meaningful, the acoustic properties of the main test object components (tissue and blood mimic) should match closely the properties of the corresponding human tissues, while the tube should ideally have little influence. The blood mimic should also represent the haemodynamic properties of blood. An acceptable flow test object has been designed to closely mimic blood flow in arteries. We have evaluated the properties of three blood mimicking fluid: two have been described recently in the literature, the third is a local design. One of these has emerged as being particularly well matched to the necessary characteristics for in-vitro work.

  7. An ideal blood mimicking fluid for doppler ultrasound phantoms

    Directory of Open Access Journals (Sweden)

    Samavat H

    2006-01-01

    Full Text Available In order to investigate the problems of detecting tumours by ultrasound it is very important to have a portable Doppler flow test object to use as a standardising tool. The flow Doppler test objects are intended to mimic the flow in human arteries. To make the test meaningful, the acoustic properties of the main test object components (tissue and blood mimic should match closely the properties of the corresponding human tissues, while the tube should ideally have little influence. The blood mimic should also represent the haemodynamic properties of blood. An acceptable flow test object has been designed to closely mimic blood flow in arteries. We have evaluated the properties of three blood mimicking fluid: two have been described recently in the literature, the third is a local design. One of these has emerged as being particularly well matched to the necessary characteristics for in-vitro work.

  8. Characterization of an inline row impingement channel for turbine blade cooling applications

    Science.gov (United States)

    Ricklick, Mark A.

    Gas turbines have become an intricate part of today's society. Besides powering practically all 200,000+ passenger aircraft in use today, they are also a predominate form of power generation when coupled with a generator. The fact that they are highly efficient, and capable of large power to weight ratios, makes gas turbines an ideal solution for many power requirement issues faced today. Designers have even been able to develop small, 'micro' turbines capable of producing efficient portable power. Part of the turbine's success is the fact that their efficiency levels have continuously risen since their introduction in the early 1800's. Along with improvements in our understanding and designs of the aerodynamic components of the turbine, as well as improvements in the areas of material design and combustion control, advances in component cooling techniques have predominantly contributed to this success. This is the result of a simple thermodynamic concept; as the turbine inlet temperature is increased, the overall efficiency of the machine increases as well. Designers have exploited this fact to the extent that modern gas turbines produce rotor inlet temperatures beyond the melting point of the sophisticated materials used within them. This has only been possible through the use of sophisticated cooling techniques, particularly in the 1st stage vanes and blades. Some of the cooling techniques employed today have been internal cooling channels enhanced with various features, film and showerhead cooling, as well as internal impingement cooling scenarios. Impingement cooling has proven to be one of the most capable heat removal processes, and the combination of this cooling feature with that of channel flow, as is done in impingement channel cooling, creates a scenario that has understandably received a great deal of attention in recent years. This study has investigated several of the unpublished characteristics of these impingement channels, including the channel

  9. Gout: radiographic findings mimicking infection

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, I.; Raymond-Tremblay, D. [Dept. of Diagnostic Radiology, Centre Hospitalier de l' Univ. de Montreal, Que. (Canada); Cardinal, E. [Dept. of Radiology, Centre Hospitalier de l' Univ. de Montreal, Que. (Canada); Beauregard, C.G. [Dept. of Diagnostic Radiology, Hopital du Sacre-Coeur de Montreal,Que. (Canada); Braunstein, E.M. [Dept. of Radiology, Indiana University Hospital (United States); Saint-Pierre, A. [Rheumatology Unit, Centre Hospitalier de l' Univ. de Montreal, Que. (Canada)

    2001-10-01

    Objective: To describe radiographic features of gout that may mimic infection. Design and patients: We report five patients with acute bacterial gout who presented with clinical as well as radiological findings mimicking acute bacterial septic arthritis or osteomyelitis. Three patients had delay in the appropriate treatment with the final diagnosis being established after needle aspiration and identification of urate crystals under polarized light microscopy. Two patients underwent digit amputation for not responding to antibiotic treatment and had histological findings confirming the diagnosis of gout. Conclusion: It is important for the radiologist to be aware of the radiological manifestations of acute gout that can resemble infection in order to avoid inappropriate diagnosis and delay in adequate treatment. The definitive diagnosis should rely on needle aspiration and a specific search for urate crystals. (orig.)

  10. Experiments and Modeling of Impinging Jets and Premixed Hydrocarbon Stagnation Flames

    Science.gov (United States)

    2005-05-26

    coupling of the acoustic properties of the two jets could lead to oscillations and instabilities in the flames. Impinging-jet flames are found to be more...the Knudsen-Weber slip correction factor [see Eq. (A.10)], τS is the Stokes time, and σ = dup/dx ∼= duf /dx is the (local) velocity gradient [see...that act on a particle in a typical flow are ΣF = FPG + FFI + FUD + FG + FSD + FTP , (A.2) where FPG = ρf ρp mp duf dt (A.3) is the pressure-gradient

  11. Rupture of thin liquid films induced by impinging air-jets.

    Science.gov (United States)

    Berendsen, Christian W J; Zeegers, Jos C H; Kruis, Geerit C F L; Riepen, Michel; Darhuber, Anton A

    2012-07-01

    Thin liquid films on partially wetting substrates are subjected to laminar axisymmetric air-jets impinging at normal incidence. We measured the time at which film rupture occurs and dewetting commences as a function of diameter and Reynolds number of the air-jet. We developed numerical models for the air flow as well as the height evolution of the thin liquid film. The experimental results were compared with numerical simulations based on the lubrication approximation and a phenomenological expression for the disjoining pressure. We achieved quantitative agreement for the rupture times. We found that the film thickness profiles were highly sensitive to the presence of minute quantities of surface-active contaminants.

  12. Radiotherapy for shoulder impingement; Bestrahlung beim Impingementsyndrom des Schultergelenks

    Energy Technology Data Exchange (ETDEWEB)

    Adamietz, B. [Universitaetsklinikum Erlangen (Germany). Inst. fuer Radiologie; Sauer, R.; Keilholz, L. [Universitaetsklinikum Erlangen (Germany). Strahlentherapeutische Klinik

    2008-05-15

    Background and Purpose: Up to now, degenerative shoulder diseases were summarized by the term 'periarthritis humeroscapularis'. Actual shoulder diseases can be differentiated etiopathologically according to a primary and secondary impingement syndrome. Narrowing of the subacromial space, which is caused by an osseous shape variant, leads to primary impingement. Secondary impingement develops, when the subacromial space is reduced by swelling tissue below the osseous shoulder roof. This study aimed for the exact diagnosis to indicate therapy and to classify the results according to the Constant score. Patients and Methods: From August 1999 to September 2002, 102 patients with 115 shoulder joint conditions underwent radiation therapy (RT). All joints received two RT series (6 x 0.5 Gy/series) applied in two to three weekly fractions, totaling a dosage of 6.0 Gy (250 kV, 15 mAs, 1-mm Cu filter). The second RT course started 6 weeks after the end of the first. 115 shoulders were examined before RT, 6 weeks after the second RT course and, finally, during the follow-up from January to May 2003. Results: Pain relief was achieved in 94/115 shoulder joints (82%) after 18-month follow-up (median). A significant difference existed between secondary impingement and primary/non-impingement according to response. Tendinosis calcarea, bursitis subdeltoidea, tendovaginitis of the long biceps tendon, and capsulitis adhaesiva responded well to therapy. Conclusion: Shoulder diseases of secondary impingement demonstrate a good response to RT. Less or no benefit was found in primary impingement syndrome or complete rotator cuff disruption and acute shoulder injuries, respectively. (orig.)

  13. Simulation of Impinging Cooling Performance with Pin Fins and Mist Cooling Adopted in a Simplified Gas Turbine Transition Piece

    Directory of Open Access Journals (Sweden)

    Tao Xu

    2014-01-01

    Full Text Available The gas turbine transition piece was simplified to a one-four cylinder double chamber model with a single row of impinging holes in the outer wall. Heat transfer augmentation in the coolant chamber was achieved through the use of pin fin structure and mist cooling, which could increase the turbulence and heat transfer efficiency. The present research is focused on heat transfer and pressure characteristics of the impinging cooling in the coolant chamber using FLUENT software. With the given diameter of impinging hole, pin fin diameter ratios D/d have been numerically studied in ranges from 1 to 2. Three different detached L were simulated. The impinging cooling performance in all cases was compared between single-phase and two-phase (imported appropriate mist flow in the coolant chamber. All the simulation results reveal that the factors of L and D/d have significant effects on the convective heat transfer. After the pin fin structure was taken, the resulting temperature decrease of 38.77 K at most compared with the result of structure without pin fins. And with the mist injecting into the cooling chamber, the area weighted average temperature got a lower value without excess pressure loss, which could satisfy the more stringent requirements in engineering.

  14. LARGE EDDY SIMULATION OF VERTICAL JET IMPINGEMENT WITH A FREE SURFACE

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-ping; LI Chi-wai; ZHANG Chang-kuang

    2006-01-01

    The flow characteristics of a 2D slot jet vertically impinging on free surfaces are numerically investigated by the Large Eddy Simulation (LES) with a dynamic Sub-Grid Scale (SGS) model. The σ-coordinate transformation is introduced to map the depth-variable physical domain to a depth-uniform computational domain. The split-operator scheme, which splits the solution procedure into advection, diffusion and pressure propagation steps, is employed to solve the instantaneous velocity and pressure field. A fully nonlinear Lagrange-Euler method is used to compute the free surface elevation. The numerical results show that the jet retains good self-similarity in the Zone of Eestablished Flow (ZEF), while the turbulence of jet shifts gradually from isotropic to anisotropic in the Zone of Surface Impingement (ZSI). When the jet approaches the free surface, the centerline velocity decreases rapidly and the flow is deflected by the free surface. Two symmetrical surface jets are formed in the Zone of Horizontal Jets (ZHJ). An approximate Guassian distribution of super-elevation is also formed on the free surface. The computed results are in good agreement with the available experimental data.

  15. Large Eddy Simulation of a cooling impinging jet to a turbulent crossflow

    Science.gov (United States)

    Georgiou, Michail; Papalexandris, Miltiadis

    2015-11-01

    In this talk we report on Large Eddy Simulations of a cooling impinging jet to a turbulent channel flow. The impinging jet enters the turbulent stream in an oblique direction. This type of flow is relevant to the so-called ``Pressurized Thermal Shock'' phenomenon that can occur in pressurized water reactors. First we elaborate on issues related to the set-up of the simulations of the flow of interest such as, imposition of turbulent inflows, choice of subgrid-scale model and others. Also, the issue of the commutator error due to the anisotropy of the spatial cut-off filter induced by non-uniform grids is being discussed. In the second part of the talk we present results of our simulations. In particular, we focus on the high-shear and recirculation zones that are developed and on the characteristics of the temperature field. The budget for the mean kinetic energy of the resolved-scale turbulent velocity fluctuations is also discussed and analyzed. Financial support has been provided by Bel V, a subsidiary of the Federal Agency for Nuclear Control of Belgium.

  16. Conjugate Heat Transfer Study at Interior Surface of NGV Leading Edge with Combined Shower Head and Impingement Cooling

    Directory of Open Access Journals (Sweden)

    Arun Kumar Pujari

    2014-01-01

    Full Text Available A computational study on conjugate heat transfer is carried out to present the behavior of nondimensional temperature and heat transfer coefficient of a Nozzle Guide Vane (NGV leading edge. Reynolds number of both mainstream flow and coolant impinging jets are varied. The NGV has five rows of film cooling holes arranged in shower head manner and four rows of impingement holes arranged in staggered manner. The results are presented by considering materials of different thermal conductivity. The results show that the mainstream flow affects the temperature distribution on the interior side of the vane leading edge for high conductivity material whereas it has negligible effects for low conductivity material. The effect of changing blowing ratio on internal heat transfer coefficient and internal surface temperature is also presented.

  17. Micromixing in the Submerged Circulative Impinging Stream Reactor

    Institute of Scientific and Technical Information of China (English)

    伍沅; 肖杨; 周玉新

    2003-01-01

    Micromixing in the submerged circulative impinging stream reactor (SCISR) developed by the authors is investigated with the Bourne's reaction scheme. The values measured for the impinging velocity, u0, under the conditions of SCISR normal operation, only is of the order of 0.1m·s-1, are much slower than that inferred,suggesting low power requirement for operation. The values of the characteristic time constant for micromixing,tM, determined in the impinging velocity range of 0.184m·s-1 < u0 < 0.326m·s-1 are ranged from 192ms to 87 ms, showing that impinging streams promotes micromixing very efficiently. The data follow approximately the relationship of tM∝ u0-1.5. A comparative study shows that the micromixing performance of SCISR is much better than that of the traditional stirred tank reactor. The tM values predicted with the existing theoretical model are systematically longer than those measured by about 2--3 times, implying that the regularity of impinging streams promoting micromixing is unclear yet.

  18. Modeling of an Impinging Oxygen Jet on Molten Bath Surface in 150 t EAF%Modeling of an Impinging Oxygen Jet on Molten Bath Surface in 150 t EAF

    Institute of Scientific and Technical Information of China (English)

    HE Chun-lai; ZHU Rong; DONG Kai; QIU Yong-quan; SUN Kai-ming

    2011-01-01

    A transient three-dimensional mathematical model has been developed to analyze the three-phase flow in a 150 t EAF (electric arc furnace) using oxygen. VOF (multiphase volume of fluid) method is used to simulate the behaviors of molten steel and slag. Numerical simulation was conducted to clarify the transient phenomena of oxygen impingement on molten bath. When oxygen jet impinges on the surface of molten bath, the slag layer is broken and the penetrated cavity in molten steel is created. Simultaneously, the wave is formed at the surface of uncovered steel on which the slag layer is pushed away by jet. The result of numerical simulations shows that the area and velocity of uncovered steel created by impingement, jet penetration depth change from 0. 10 m2 , 0. 012 5 m/s, 3.58 cm to 0.72 m2 , 0. 1445 m/s, 11.21 cm, when the flow rate of an oxygen lance varies from 500 to 2000 m3/h. The results have been validated against water model experiments. More specially, the relation between the penetration depth and oxygen flow rate predicted by numerical simulation has been found to agree well with that concluded by water model.

  19. Elliptic Length Scales in Laminar, Two-Dimensional Supersonic Flows

    Science.gov (United States)

    2015-06-01

    adiabatic wall flows over compression ramps and flows with shock impingements. The new correlations are derived from existing numerical data and...developed for 2D, laminar adiabatic wall flows over compression ramps and flows with shock impingements. These correlations are derived from existing...characterizing the influence of shocks and compression ramps on flat plate flows is presented. New correlations for laminar compressive interactions on

  20. Humanlike Robots - Synthetically Mimicking Humans

    Science.gov (United States)

    Bar-Cohen, Yoseph

    2012-01-01

    Nature inspired many inventions and the field of technology that is based on the mimicking or inspiration of nature is widely known as Biomimetics and it is increasingly leading to many new capabilities. There are numerous examples of biomimetic successes including the copying of fins for swimming, and the inspiration of the insects and birds flight. More and more commercial implementations of biomimetics are appearing and behaving lifelike and applications are emerging that are important to our daily life. Making humanlike robots is the ultimate challenge to biomimetics and, for many years, it was considered science fiction, but such robots are becoming an engineering reality. Advances in producing such robot are allowing them to perform impressive functions and tasks. The development of such robots involves addressing many challenges and is raising concerns that are related to fear of their application implications and potential ethical issues. In this paper, the state-of-the-art of humanlike robots, potential applications and challenges will be reviewed.

  1. Mounding of a non-Newtonian jet impinging on a solid substrate.

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; Grillet, Anne Mary; Roberts, Scott A.; Baer, Thomas A. (Procter & Gamble, Cincinnati, OH); Rao, Rekha Ranjana

    2010-06-01

    When a fluid jet impinges on a solid substrate, a variety of behaviors may occur around the impact region. One example is mounding, where the fluid enters the impact region faster than it can flow away, forming a mound of fluid above the main surface. For some operating conditions, this mound can destabilize and buckle, entraining air in the mound. Other behaviors include submerging flow, where the jet impinges into an otherwise steady pool of liquid, entraining a thin air layer as it enters the pool. This impact region is one of very high shear rates and as such, complex fluids behave very differently than do Newtonian fluids. In this work, we attempt to characterize this range of behavior for Newtonian and non-Newtonian fluids using dimensionless parameters. We model the fluid as a modified Bingham-Carreau-Yasuda fluid, which exhibits the full range of pseudoplastic flow properties throughout the impact region. Additionally, we study viscoelastic effects through the use of the Giesekus model. Both 2-D and 3-D numerical simulations are performed using a variety of finite element method techniques for tracking the jet interface, including Arbitrary Lagrangian Eulerian (ALE), diffuse level sets, and a conformal decomposition finite element method (CDFEM). The presence of shear-thinning characteristics drastically reduces unstable mounding behavior, yet can lead to air entrainment through the submerging flow regime. We construct an operating map to understand for what flow parameters mounding and submerging flows will occur, and how the fluid rheology affects these behaviors. This study has many implications in high-speed industrial bottle filling applications.

  2. Virtual prototype simulation on underwater hydraulic impingement shovel

    Institute of Scientific and Technical Information of China (English)

    LIU He-ping; LUO A-ni; MENG Qing-xin

    2007-01-01

    The virtual prototype technology is applied to the design of the hydraulic impingement shovel,which is to increase the reliability of the design. The work principle of hydraulic impingement shovel is expatiated, and its dynamic equations are established. The 3D model of virtual prototype is built by PRO/E. Then the couple between the mechanical body of prototype and the hydraulic system is completed by virtue of ADAMS. Finally, the simulation is made on the virtual prototype. The simulation results show that the design of underwater hydraulic impingement shovel is rational. The virtual prototype technology could lay sound foundation of successful manufacturing of physical prototype for the first time and offer highly effective and feasible means for the design and production of underwater equipments.

  3. Influence of Liquid Viscosity on Droplet Impingement on Superhydrophobic Surfaces

    CERN Document Server

    Pearson, John T; Webb, Brent W

    2010-01-01

    This fluid dynamics video describes droplet impingement experiments performed on superhydrophobic surfaces. When droplets of pure water are impinged upon superhydrophobic surfaces, a region of thin coherent jets are observed for Weber numbers between 5 and 15. Also, peripheral splashing is observed for Weber numbers above about 200. When the viscosity of the droplet is increased by mixing glycerol with the water, the thin jets are not observed and peripheral splashing is delayed somewhat. In the Weber number range where pure water droplets are observed to splash peripherally, the water/glycerol droplets are observed to have two-pronged jets.

  4. Bone scintigraphy in costo-iliac impingement syndrome

    DEFF Research Database (Denmark)

    Madsen, Jan L

    2008-01-01

    Abstract: A syndrome of back pain caused by impingement of the lowest ribs against the iliac crest has been described in patients with osteoporotic vertebral fractures and loss of height of the patient. A case is presented of an 81-year-old woman with a long history of osteoporosis with compressi...... fractures of several thoracic and lumbar vertebrae. She presented with progressive lower back pain and weight loss. Bone scintigraphy revealed increased uptake in the lower ribs on both sides compatible with the costo-iliac impingement syndrome. There were no signs of bone metastases....

  5. Erosion onset of a cohesionless granular medium by an immersed impinging round jet

    Science.gov (United States)

    Brunier-Coulin, Florian; Cuéllar, Pablo; Philippe, Pierre

    2017-03-01

    Among different devices developed quite recently to quantify the resistance to erosion of natural soil within the broader context of dyke safety, the most commonly used is probably the jet erosion test in which a scouring crater is induced by impingement of an immersed water jet. A comprehensive experimental investigation on the jet erosion in the specific situation of a cohesionless granular material is presented here. The tests were performed by combining special optical techniques allowing for an accurate measurement of the scouring onset and evolution inside an artificially translucent granular sample. The impinging jet hydrodynamics are also analyzed, empirically validating the use of a self-similar theoretical framework for the laminar round jet. The critical conditions at the onset of erosion appear to be best described by a dimensionless Shields number based on the inertial drag force created by the fluid flow on the eroded particles rather than on the pressure gradients around them. To conclude, a tentative empirical model for the maximal flow velocity initiating erosion at the bottom of the scoured crater is put forward and discussed in the light of some preliminary results.

  6. Numerical Simulation of Jet Behavior and Impingement Characteristics of Preheating Shrouded Supersonic Jets

    Institute of Scientific and Technical Information of China (English)

    Guang-sheng WEI; Rong ZHU; Ting CHENG; Fei ZHAO

    2016-01-01

    As a novel supersonic j et technology,preheating shrouded supersonic j et was developed to deliver oxygen into molten bath efficiently and affordably.However,there has been limited research on the jet behavior and im-pingement characteristics of preheating shrouded supersonic j ets.Computational fluid dynamics (CFD)models were established to investigate the effects of main and shrouding gas temperatures on the characteristics of flow field and impingement of shrouded supersonic j et.The preheating shrouded supersonic j et behavior was simulated and meas-ured by numerical simulation and j et measurement experiment respectively.The influence of preheating shrouded su-personic j et on gas j et penetration and fluid flow in liquid bath was calculated by the CFD model which was validated against water model experiments.The results show that the uptrend of the potential core length of shrouded super-sonic j et would be accelerated with increasing the main and shrouding gas temperatures.Also,preheating supersonic j ets demonstrated significant advantages in penetrating and stirring the liquid bath.

  7. Aortic aneurysm mimicking a right atrial mass.

    Science.gov (United States)

    Mohamed, Ahmed; Elsayed, Mahmoud; Kalra, Rajat; Bulur, Serkan; Nanda, Navin C

    2016-10-01

    We present a case of a 54-year-old female who was initially thought to have a cystic mass in the right atrium on two-dimensional transthoracic echocardiography. Careful transducer angulation and off-axis imaging showed this mass-like effect was produced by an aortic root aneurysm impinging on the right atrium. © 2016, Wiley Periodicals, Inc.

  8. CFD analysis of the impingement cooling effect of the coolant jet caused by the T56 1st stage disc metering hole

    CSIR Research Space (South Africa)

    Snedden, Glen C

    2003-09-01

    Full Text Available OF THE IMPINGEMENT COOLING EFFECT OF THE COOLANT JET CAUSED BY THE T56 1ST STAGE DISC METERING HOLE ISABE-2003-1065 Glen C. Snedden CSIR, Defencetek, P O Box 395 Pretoria, 0001, South Africa Tony Lambert Rolls-Royce Indianapolis, Indiana, USA Abstract... the cavities via metering holes drilled through the curvic-coupling web. As a result of physical restrictions during the manufacturing process these holes are angled toward the face of the disc and result in flow impinging on the rear surface of the 1st...

  9. Anterior internal impingement of the shoulder in rugby players and other overhead athletes

    Directory of Open Access Journals (Sweden)

    Siddharth R. Shah, MBBS, MSc Sports Medicine (UK, MRCS-Ed

    2017-04-01

    Conclusion: This series of anterior internal impingement, which we believe is the largest in the literature to date, demonstrates the value of an to assess and successfully treat overhead athletes with anterior impingement syndrome.

  10. Flume length and post-exercise impingement affect anaerobic metabolism in brook charr Salvelinus fontinalis.

    Science.gov (United States)

    Tudorache, C; O'Keefe, R A; Benfey, T J

    2010-02-01

    The effect of flume length and impingement time on post-exercise lactate concentrations in brook charr Salvelinus fontinalis were examined. Swimming in longer flumes increased lactate concentrations, as does impingement after swimming in short flumes.

  11. Physiotherapy improves patient reported shoulder function and health status in patients with subacromial impingement syndrome

    DEFF Research Database (Denmark)

    Storgaard, Filip Holst; Pedersen, Christina Gravgaard; Jensen, Majbritt Lykke

    Physiotherapy improves patient reported shoulder function and health status in patients with subacromial impingement syndrome.......Physiotherapy improves patient reported shoulder function and health status in patients with subacromial impingement syndrome....

  12. Droplet impaction on solid surfaces exposed to impinging jet fires

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Zia

    2005-12-15

    The thermal response of hot surfaces exposed to impinging jet fire and subsequent impacting water droplets is investigated. The research was done mainly experimentally by utilizing three different concepts. This included experiments on a laboratory scale steel plate and large outdoor fire tests with a quadratic steel channel and steel plates. Besides the horizontal jet flame itself was characterized in a comprehensive study. As a comparative study, the last three types of the experiment were additionally modeled by the CFD-code Kameleon FireEx for validation of results. The purpose of the experiments done on bench scale steel plate (L x W x T : 300 x 200 x 8 mm) was mainly to map data on wetting temperature, water droplet size, droplet impingement angle, and droplet velocity prior to large scale jet fire tests. The droplet release angle normal to hot surface gives best cooling effect, when the surface is oriented in upright position. The partial wetting begins at about 165 degrees C. When the surface is positioned in horizontal plane, the droplet of about 5 mm in diameter wets the hot surface partially at around 240-250 degrees C within an impaction distance of 20 cm. At about 150 degrees C, the droplet is entirely attached to the surface with almost zero contact angle, and cools down the solid at a critical heat flux equivalent to 1750 kW/m{sup 2}. The cooling effectiveness is about 8 % with a Weber number of 68. Although in the event of horizontal channel (L x W x T : 1000 x 200 x 8 mm) water droplets were not applied, however, the knowledge gained with jet fire tests gave valuable information about temperature progress in solids (steels and insulation) and their response to impinging jet fire during long duration experiments. The temperature of the insulated area of the channel keeps 200 degrees C below that of the exposed surface, as long as the insulation material remained intact. Upon long test fire durations, the insulation either burns or degrades despite

  13. Droplet impaction on solid surfaces exposed to impinging jet fires

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Zia

    2005-12-15

    The thermal response of hot surfaces exposed to impinging jet fire and subsequent impacting water droplets is investigated. The research was done mainly experimentally by utilizing three different concepts. This included experiments on a laboratory scale steel plate and large outdoor fire tests with a quadratic steel channel and steel plates. Besides the horizontal jet flame itself was characterized in a comprehensive study. As a comparative study, the last three types of the experiment were additionally modeled by the CFD-code Kameleon FireEx for validation of results. The purpose of the experiments done on bench scale steel plate (L x W x T : 300 x 200 x 8 mm) was mainly to map data on wetting temperature, water droplet size, droplet impingement angle, and droplet velocity prior to large scale jet fire tests. The droplet release angle normal to hot surface gives best cooling effect, when the surface is oriented in upright position. The partial wetting begins at about 165 degrees C. When the surface is positioned in horizontal plane, the droplet of about 5 mm in diameter wets the hot surface partially at around 240-250 degrees C within an impaction distance of 20 cm. At about 150 degrees C, the droplet is entirely attached to the surface with almost zero contact angle, and cools down the solid at a critical heat flux equivalent to 1750 kW/m{sup 2}. The cooling effectiveness is about 8 % with a Weber number of 68. Although in the event of horizontal channel (L x W x T : 1000 x 200 x 8 mm) water droplets were not applied, however, the knowledge gained with jet fire tests gave valuable information about temperature progress in solids (steels and insulation) and their response to impinging jet fire during long duration experiments. The temperature of the insulated area of the channel keeps 200 degrees C below that of the exposed surface, as long as the insulation material remained intact. Upon long test fire durations, the insulation either burns or degrades despite

  14. Experimental study of highly viscous impinging jets

    Energy Technology Data Exchange (ETDEWEB)

    Gomon, M. [Univ. of Texas, Austin, TX (United States). Dept. of Mechanical Engineering

    1998-12-01

    The objective of this research is to study the behavior of highly viscous gravity-driven jets filling a container. Matters of interest are the formation of voids in the fluid pool during the filling process and the unstable behavior of the fluid in the landing region which manifests itself as an oscillating motion. The working fluids used in this research are intended to simulate the flow behavior of molten glass. Qualitative and quantitative results are obtained in a parametric study. The fraction of voids present in the fluid pool after the filling of the container is measured for different parameter values of viscosity and mass flow rate. Likewise, frequencies of the oscillating jet are measured. Results are inconclusive with regard to a correlation between parameter settings and void fractions. As for frequencies, power law correlations are established.

  15. Quantifying Cell Adhesion through Impingement of a Controlled Microjet

    NARCIS (Netherlands)

    Visser, Claas Willem; Gielen, Marise V.; Hao, Zhenxia; Gac, Le Severine; Lohse, Detlef; Sun, Chao

    2015-01-01

    The impingement of a submerged, liquid jet onto a cell-covered surface allows assessing cell attachment on surfaces in a straightforward and quantitative manner and in real time, yielding valuable information on cell adhesion. However, this approach is insufficiently characterized for reliable and r

  16. Hindfoot endoscopy for posterior ankle impingement. Surgical technique

    NARCIS (Netherlands)

    van Dijk, C.N.; de Leeuw, P.A.J.; Scholten, P.E.

    2009-01-01

    BACKGROUND: The surgical treatment of posterior ankle impingement is associated with a high rate of complications and a substantial time to recover. An endoscopic approach to the posterior ankle (hindfoot endoscopy) may lack these disadvantages. We hypothesized that hindfoot endoscopy causes less mo

  17. Anterior Inferior Iliac Spine (AIIS) and Subspine Hip Impingement

    Science.gov (United States)

    Carton, Patrick; Filan, David

    2016-01-01

    Summary Background Abnormal morphology of the anterior inferior iliac spine (AIIS) and the subspine region of the acetabular rim are increasingly being recognised as a source of symptomatic extra-articular hip impingement. This review article aims to highlight important differences in the pathogenesis, clinical presentation and management of extra-articular hip impingement from both the AIIS and subspine bony regions, and the outcome following surgical intervention. Methods A literature review was undertaken to examine the supporting evidence for AIIS and subspine hip impingement. A narrative account of the Author’s professional experience in this area, including operative technique for arthroscopic correction, is also presented. Results Abnormal morphology of the AIIS and subspine region has been classified using cadaveric, radiological and arthroscopic means; the clinical presentation and operative treatment has been documented in several case series studies. Dual pathology is often present - recognition and treatment of both intra- and extra-articular components are necessary for good postoperative outcome. Conclusions AIIS and sub-spine hip impingement should be considered as distinct pathological entities, which may also co-exist. Symptom relief can be expected following arthroscopic deformity correction with the treatment of concomitant intra-articular pathology. Failure to recognise and treat the extra-articular component may affect postoperative outcome. Level of evidence V. PMID:28066737

  18. Conjugate Heat Transfer Study of Combined Impingement and Showerhead Film Cooling Near NGV Leading Edge

    Directory of Open Access Journals (Sweden)

    Dileep Chandran

    2015-01-01

    Full Text Available A computational and experimental study is carried out on the leading edge region of a typical gas turbine NGV, cooled by a combination of impingement and showerhead film cooling. A detailed flow and conjugate heat transfer study has revealed the complex flow structure owing to the coolant-mainstream interaction and the influence of vane material thermal conductivity. The local effectiveness values obtained by the computations agreed well with the experimental data from IR thermography. The effect of blowing ratio on the overall effectiveness is found to be strongly dependent on the vane material conductivity. The effect of blowing ratio is also found to be different towards the pressure and suction sides of the stagnation region. However, the overall effectiveness is found to decrease by about 12% and 6% for low and high conducting materials, respectively, with an increase in mainstream Reynolds number from Re=4.8×105 to 14.4×105.

  19. Investigation of laminar to turbulent transition phenomena effects on impingement heat transfer

    Science.gov (United States)

    Isman, Mustafa Kemal; Morris, Philip J.; Can, Muhiddin

    2016-10-01

    Turbulent impinging air flow is investigated numerically by using the ANSYS-CFX® code. All computations are performed by considering three-dimensional, steady, and incompressible flow. Three different Reynolds averaged Navier-Stokes (RANS) turbulence models and two Reynolds stress models (RSM's) are employed. Furthermore three different laminar to turbulent transition (LTT) models are employed with the shear stress transport (SST) and the baseline (BSL) models. Results show that predictions of the SST and two RSM's are very close each other and these models' results are in better agreement with the experimental data when all Reynolds numbers used in this study are considered. Secondary maxima in Nusselt number can be seen only if the LTT formula is employed with SST and BSL models.

  20. A Research on Improved Impinging Stream Reactor%一种改进型撞击流反应器的研究

    Institute of Scientific and Technical Information of China (English)

    刘雪晴; 鲁录义; 张燕平; 黄树红

    2016-01-01

    提出了一种进口速度动态变化的撞击流反应器,其撞击面在中心位置波动,增加了颗粒的有效混合区域,可进一步加强相间的传热传质。并采用计算流体动力学对改进型的撞击反应器进行数值模拟,模拟中采用了三角形和抛物线形两种流型,并与传统直线形流型进行对比分析。分析结果表明,改进型的撞击流反应器中颗粒活动区域得到加强,与经典的撞击流反应器相比有明显的优势。%A new impinging stream reactor with dynamically-changed inlet velocity was proposed,whose im-pact surface fluctuates at the central position in the impinging stream reactor to greatly increase the particles’ effective mixing zone and further strengthen the heat and mass transfer between phases.Simulating this im-proved impinging stream reactor with CFD software and adopting triangle and parabolic flow patterns and com-paring them with traditional linear flow pattern in the simulation show that,the active area of particles is greatly increased in the improved impinging stream reactor;and as compared to the traditional impinging streams,the improved impinging stream reactor has obvious advantages.

  1. Detailed heat transfer measurements of impinging jet arrays issued from grooved surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Su, Lo May; Chang, Shyy Woei [Department of Marine Engineering National Kaohsiung Institute of Marine Technology, Kaohsiung, Taiwan (China)

    2002-07-01

    Heat transfer augmentation of impinging jet-array with very small separation distances (S/D{sub j}<1) is attempted by using the grooved orifice plate through which the nozzles with different diameters are fitted. The combined effects of groove and nozzle-size distribution in an array have demonstrated considerable influences on heat transfers via their impacts on inter-jet reactions. With a specified coolant flow rate; the detailed heat transfer distributions over the impinging surfaces of three tested arrays are compared to reveal the optimal selections of separation distance and array configuration. Heat transfer modifications caused by varying jet Reynolds number (Re) and separation distance (S/D{sub j}) over the ranges of 1000{<=}Re{<=}4000 and 0.1{<=}S/D{sub j}{<=}8 are examined for each test array. In conformity with the experimentally revealed heat transfer physics, a regression-type analysis is performed to develop the correlations of spatially-averaged Nusselt numbers, which permit the individual and interactive effect of Re and S/D{sub j} to be evaluated. (authors)

  2. A Study of Under-expanded Moist Air Jet Impinging on a Flat Plate

    Institute of Scientific and Technical Information of China (English)

    Yumiko OTOBE; Shigeru MATSUO; Masanori TANAKA; Hideo KASHIMURA; Heuy-Dong KIM; Toshiaki SETOGUCHI

    2005-01-01

    When a gas expands through a convergent nozzle in which the ratio of the ambient to the stagnation pressures is higher than that of the critical one, the issuing jet from the nozzle is under-expanded. If a flat plate is placed normal to the jet at a certain distance from the nozzle, a detached shock wave is formed at a region between the nozzle exit and the plate. In general, supersonic moist air jet technologies with non-equilibrium condensation are very often applied to industrial manufacturing processes. In spite of the importance in major characteristics of the supersonic moist air jets impinging to a solid body, its qualitative characteristics are not known satisfactorily. In the present study, the effect of the non-equilibrium condensation on the under-expanded air jet impinging on a vertical flat plate is investigated numerically in the case with non-equilibrium condensation, frequency of oscillation for the flow field becomes larger than that without the non-equilibrium condensation, and amplitudes of static pressure become small compared with those of dry air. Furthermore, the numerical results are compared with experimental ones.

  3. Influence of spray characteristics on heat flux in dual phase spray impingement cooling of

    Directory of Open Access Journals (Sweden)

    Santosh Kumar Nayak

    2016-09-01

    Full Text Available The effects of variation of spray characteristics (mass flux, inlet pressure, flow rate, nozzle tip to target distance and plate thickness on heat flux were systematically investigated. The round spray released from a full cone internally mix atomizing nozzle was impinged with a wide range of air and water pressures on stationary hot steel surface of definite dimension. The effect of each parameter was examined while keeping others nearly fixed. Four different plate thicknesses i.e., 4 mm, 6 mm, 8 mm and 10 mm were tested and effect of plate thickness on heat transfer was determined. Surface heat flux at each experimental condition was computed from the transient temperature history measured by K-type thermocouples embedded at bottom surface of the plate. The mass impingement density was measured by the help of a simple mechanical patternator. The maximum surface heat flux of 4895.525 kW/m2 was achieved at an inlet water pressure of 4 bar, air pressure of 3 bar and nozzle height of 120 mm for an initial temperature of 850 °C of the 4 mm steel plate.

  4. Recurrent epiploic appendagitis mimicking appendicitis and cholecystitis

    Science.gov (United States)

    Hearne, Christopher B.; Taboada, Jorge

    2017-01-01

    Epiploic appendagitis (EA) is a rare cause of acute abdominal pain caused by inflammation of an epiploic appendage. It has a nonspecific clinical presentation that may mimic other acute abdominal pathologies on physical exam, such as appendicitis, diverticulitis, or cholecystitis. However, EA is usually benign and self-limiting and can be treated conservatively. We present the case of a patient with two episodes of EA, the first mimicking acute appendicitis and the second mimicking acute cholecystitis. Although recurrence of EA is rare, it should be part of the differential diagnosis of acute, localized abdominal pain. A correct diagnosis of EA will prevent unnecessary hospitalization, antibiotic use, and surgical procedures. PMID:28127129

  5. Extra-articular hip impingement: a narrative review of the literature

    Science.gov (United States)

    Cheatham, Scott W.

    2016-01-01

    There is growing subgroup of patients with poor outcomes after hip arthroscopy for intra-articular pathology suggesting unrecognized cause(s) of impingement may exist. Extra-articular hip impingement (EHI) is an emerging group of conditions that have been associated with intra-articular causes of impingement and may be an unrecognized source of pain. EHI is caused by abnormal contact between the extra-articular regions of the proximal femur and pelvis. This review discusses the most common forms for EHI including: central iliopsoas impingement, subspine impingement, ischiofemoral impingement, and greater trochanteric-pelvic impingement. The clinical presentation of each pathology will be discussed since EHI conditions share similar clinical features as the intra-articular pathology but also contain some unique characteristics. PMID:27069266

  6. 对撞流干燥的实验与理论研究%Experimental and Theoretical Analysis of the Impinging Stream Drying

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The experiments of one-stage semi-circular and two-stage semi-circular impinging stream drying as wellas the vertical and semi-circular combined impinging stream drying were carried out. The velocity distribution andthe mean residence time of particles, and the influence of various factors on drying characteristics were studied. Amathematical model of granular material drying in a semi-circular impinging stream dryer was proposed, in whichthe flow characteristics as well as the heat and mass transfer mechanisms were considered. Reasonable numericalmethods were used to solve the equations. Under various conditions, the calculated results agree well with theexperimental data. The unsteady-state drying dynamic equation, as well as the variations of drying rate andmoisture content versus time were obtained. The results indicate that constant drying rate period does not existin a semi-circular impinging stream dryer. Appropriate semi-circular stage number and curvature radius, flow-rateratio, air velocity, and higher inlet air temperature should be used for enhancing the drying process.

  7. The distal radial decompression osteotomy for ulnar impingement syndrome.

    Science.gov (United States)

    Krimmer, Hermann; Unglaub, Frank; Langer, Martin F; Spies, Christian K

    2016-01-01

    The decompression of the distal radioulnar joint (DRUJ) is performed by ulnar translation of the radial shaft proximal to the sigmoid notch, i.e. detensioning of the distal part of the interosseous membrane (DIOM) while containment of the DRUJ is achieved by closed wedge osteotomy of the radius. The osteotomy shortens the radius which entails detensioning of the triangular fibrocartilage complex (TFCC). Facilitating the modified Henry approach to the distal palmar radius a radial based wedge osteotomy is applied. The proximal osteotomy is proximal to the ulnar head and distal osteotomy is proximal to the sigmoid notch to prevent iatrogenic impingement. Ulnar translation of the radial shaft is performed to loosen the DIOM. The closed wedge osteotomy reduces radial inclination which will foster containment of the DRUJ. Distal radial decompression osteotomy of the DRUJ preserves DRUJ function while relieving painful impingement. Further surgical interventions are not compromised in case of failure.

  8. Experimental comparative study of doublet and triplet impinging atomization of gelled fuel based on PIV

    Science.gov (United States)

    Yang, Jian-lu; Li, Ning; Weng, Chun-sheng

    2016-10-01

    Gelled propellant is promising for future aerospace application because of its combination of the advantages of solid propellants and liquid propellants. An effort was made to reveal the atomization properties of gelled fuel by particle image velocimetry (PIV) system. The gelled fuel which was formed by gasoline and Nano-silica was atomized using a like-doublet impingement injector and an axisymmetric like-triplet impingement injector. The orifice diameter and length of the nozzle used in this work were of 0.8mm, 4.8mm, respectively. In the impinging spray process, the impingement angles were set at 90° and 120°, and the injection pressures were of 0.50MPa and 1.00MPa. The distance from the exit of the orifice to the impingement point was fixed at 9.6mm. In this study, high-speed visualization and temporal resolution particle image velocimetry techniques were employed to investigate the impingement atomization characteristics. The experimental investigation demonstrated that a long narrow high speed droplets belt formed around the axis of symmetry in the like-doublet impinging atomization area. However, there was no obvious high-speed belt with impingement angle 2θ = 90° and two high-speed belts appeared with impingement angle 2θ = 120° in the like-doublet impingement spray field. The high droplet velocity zone of the like-doublet impingement atomization symmetrically distributed around the central axis, and that of the like-triplet impingement spray deflected to the left of the central axis - opposite of injector. Although the droplets velocity distribution was asymmetry of like-triplet impingement atomization, the injectors were arranged like axisymmetric conical shape, and the cross section of spray area was similar to a circle rather than a narrow rectangle like the like-doublet impingement atomization.

  9. Advances and challenges in explaining fuel spray impingement: How much of single droplet impact research is useful?

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, A.L.N.; Moita, A.S.; Panao, M.R. [Instituto Superior Tecnico, Laboratory of Thermofluids, Combustion and Energy Systems at IN+, Av Rovisco Pais, 1049 Lisboa, Codex (Portugal)

    2010-10-15

    The impingement of fuel spray onto interposed surfaces in an IC engine, equipped either with a direct or an indirect injection system, is a fundamental issue affecting mixture preparation prior to combustion and, therefore, also affecting engine performance and pollutant emissions. In this context, the development of fuel injection systems relies on accurate knowledge of the fluid dynamic and thermal processes occurring during spray/wall interaction. Injection systems however, are very complex and the background physics requires fundamental studies, performed at simplified flow geometries. In particular, the impact of individual droplets has been extensively used to describe the behaviour of spray impact and to predict its outcome, despite the known fact that a spray does not behave exactly as a summation of individual droplets; then, researchers incorporate all the governing parameters. The present paper offers a critical review of the investigations reported in the literature on spray-wall impact relevant to IC engines, in an attempt to address the rationale of describing spray-wall interactions based on the knowledge of single droplet impacts. Moreover, although the review was first aimed at fuel-spray impingement in IC engines, it also became relevant to provide a systematization of the current state of the art, which can be useful to the scientific community involved with droplet and spray impingement phenomena. (author)

  10. Inline Array Jet Impingement Cooling Using Al2O3 / Water Nanofluid In A Plate Finned Electronic Heat Sink

    Directory of Open Access Journals (Sweden)

    R. Reji Kumar

    2016-07-01

    Full Text Available - Jet impingement cooling is a technique used for cooling the electronic systems. In this work, heat transfer and pressure drop characteristics of deionized water and Al2O3/water nanofluid in an electronic heat sink having aluminium plate fins and provision for jet impingement cooling have been studied. A novel heat sink contains two rows of plate fins of size 29mm x 24mm x 0.56mm. A thin plate having 110 holes of diameter 2.5 mm is used to produce number of jets. The plate is kept inside the heat sink in such a way that H/dn is 5.2 mm and adjacent jet spacing is 2mm. The overall dimension of the heat sink is 60x60x 65 mm. For this work we prepared a Al2O3/water nanofluid by dispersing specified quantity of nanoparticles in to deionized water by using a ultrasonic bath. Experiments were conducted under constant heat flux condition and the volume flow rate of the fluid was in the range of 1.315 to 2.778. It is found from the results that the nanofluid removes heat better than water in the jet impingement cooling with very low rise in pressure drop.

  11. Lymphomatoid granulomatosis mimicking interstitial lung disease.

    Science.gov (United States)

    Braham, Emna; Ayadi-Kaddour, Aïda; Smati, Belhassen; Ben Mrad, Sonia; Besbes, Mohammed; El Mezni, Faouzi

    2008-11-01

    Lymphoid granulomatosis is a rare form of pulmonary angiitis. This case report presents a patient with lymphoid granulomatosis in whom the clinical presentation, radiological features and the partial response to corticosteroid therapy mimicked interstitial lung disease. Lymphoid granulomatosis was only diagnosed at post-mortem examination. The range of reported clinical presentations, diagnostic approaches and outcomes are described.

  12. Ovarian Heterotopic Pregnancy Clinically Mimicking Endometrioma

    Directory of Open Access Journals (Sweden)

    Nilüfer ONAK KANDEMİR

    2010-01-01

    Full Text Available Heterotopic pregnancy is a very uncommon entity with a difficult preoperative diagnosis. In the present study, we presented an ovarian heterotopic pregnancy case, clinically mimicking endometrioma developed in a 33-year-old female following an in vitro fertilization procedure. The importance of clinical, histopathological, and immunohistochemical examinations in the diagnosis of heterotopic pregnancy are emphasized.

  13. An adult intussusception mimicking early appendicitis

    Institute of Scientific and Technical Information of China (English)

    Wei-Chun Tseng; Cheng-Ting Hsiao; Yu-Cheng Hung

    2012-01-01

    Adult intussusception is rare with variable clinical presentation. We reported a case of adult intussusception presenting with symptoms mimicking acute appendicitis. The patient presented as an abdominal pain from epigastric area with shifting gradually to RLQ. The atypical presentation of adult intussusception remains a diagnostic challenge to the emergency physician.

  14. Acute dystonia mimicking angioedema of the tongue

    DEFF Research Database (Denmark)

    Rasmussen, Eva Rye; Pallesen, Kristine A U; Bygum, Anette

    2013-01-01

    We report a case of acute dystonia of the face, jaw and tongue caused by metoclopramide and mimicking angioedema. The patient had attacks for several years before the correct diagnosis was made and we present the first ever published video footage of an attack. This adverse drug reaction is known...

  15. Subacromial Tenoxicam Injection in the Treatment of Impingement Syndrome

    OpenAIRE

    Çift, Hakan; Özkan, Feyza Ünlü; Şeker, Ali; İşyar, Mehmet; Ceyhan, Erman; Mahiroğulları, Mahir

    2014-01-01

    Objectives: As subacromial bursa injection is widely used for pain relief and functional improvements in patients with periarticular shoulder disorder, we aimed to present our results of subacromial tenoxicam injection in the treatment of impingement syndrome. Methods: Patients presented to the Department of Orthopaedics and Traumatology, Istanbul Medipol University with the primary complaints of shoulder pain from January 2012 to June 2013 were selected. Those who met the following inclusion...

  16. Radiographic Evidence of Femoroacetabular Impingement in Athletes With Athletic Pubalgia

    OpenAIRE

    Economopoulos, Kostas J.; Milewski, Matthew D.; Hanks, John B.; Hart, Joseph M.; Diduch, David R.

    2014-01-01

    Background: Two of the most common causes of groin pain in athletes are femoroacetabular impingement (FAI) and athletic pubalgia. An association between the 2 is apparent, but the prevalence of radiographic signs of FAI in patients undergoing athletic pubalgia surgery remains unknown. The purpose of this study was to determine the prevalence of radiologic signs of FAI in patients with athletic pubalgia. Hypothesis: We hypothesized that patients with athletic pubalgia would have a high prevale...

  17. The influence of material hardness on liquid droplet impingement erosion

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Nobuyuki, E-mail: fujisawa@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Yamagata, Takayuki, E-mail: yamagata@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Takano, Shotaro; Saito, Kengo [Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Morita, Ryo; Fujiwara, Kazutoshi; Inada, Fumio [Central Research Institute of Electric Power Industry, 2-11-1, Iwatokita, Komae, Tokyo 201-8511 (Japan)

    2015-07-15

    Highlights: • Liquid droplet impingement erosion is studied for various metal materials. • Average power dependency on droplet velocity is found as 7. • Power dependency on Vickers hardness is found as −4.5. • An empirical formula is constructed for erosion rates of metal materials. • Predicted erosion rate is well correlated with experiment within a factor of 1.5. - Abstract: This paper describes the experimental study on the liquid droplet impingement erosion of metal materials to understand the influence of material hardness on the erosion rate. The experiment is carried out using a water spray jet apparatus with a condition of relatively thin liquid film thickness. The metal materials tested are pure aluminum, aluminum alloy, brass, mild steel, carbon steel and stainless steel. The liquid droplets considered are 30 ± 5 μm in volume average diameter of water, which is the same order of droplet diameter in the actual pipeline in nuclear/fossil power plants. In order to understand the influence of material hardness on the liquid droplet impingement erosion, the scanning electron microscope (SEM) observation on the eroded surface and the measurement of erosion rate are carried out in the terminal stage of erosion. The experimental results indicate that the erosion rates are expressed by the droplet velocity, volume flux, Vickers hardness and the liquid film thickness, which are fundamentals of the liquid droplet impingement erosion. The empirical formula shows that the power index for droplet velocity dependency is found to be 7 with a scattering from 5 to 9 depending on the materials, while the power index for Vickers hardness dependency is found as −4.5.

  18. Reduction of glycine particle size by impinging jet crystallization.

    Science.gov (United States)

    Tari, Tímea; Fekete, Zoltán; Szabó-Révész, Piroska; Aigner, Zoltán

    2015-01-15

    The parameters of crystallization processes determine the habit and particle size distribution of the products. A narrow particle size distribution and a small average particle size are crucial for the bioavailability of poorly water-soluble pharmacons. Thus, particle size reduction is often required during crystallization processes. Impinging jet crystallization is a method that results in a product with a reduced particle size due to the homogeneous and high degree of supersaturation at the impingement point. In this work, the applicability of the impinging jet technique as a new approach in crystallization was investigated for the antisolvent crystallization of glycine. A factorial design was applied to choose the relevant crystallization factors. The results were analysed by means of a statistical program. The particle size distribution of the crystallized products was investigated with a laser diffraction particle size analyser. The roundness and morphology were determined with the use of a light microscopic image analysis system and a scanning electron microscope. Polymorphism was characterized by differential scanning calorimetry and powder X-ray diffraction. Headspace gas chromatography was utilized to determine the residual solvent content. Impinging jet crystallization proved to reduce the particle size of glycine. The particle size distribution was appropriate, and the average particle size was an order of magnitude smaller (d(0.5)=8-35 μm) than that achieved with conventional crystallization (d(0.5)=82-680 μm). The polymorphic forms of the products were influenced by the solvent ratio. The quantity of residual solvent in the crystallized products was in compliance with the requirements of the International Conference on Harmonization.

  19. Brachial plexus impingement: an unusual complication of bilateral breast augmentation.

    Science.gov (United States)

    Berry, M G; Stanek, J J

    2008-03-01

    Breast augmentation is one of the most commonly performed aesthetic procedures, with many studies documenting the early and long-term complications that might be expected. This report describes the case of an active young woman who experienced severe pain, particularly with movement. Surgical exploration showed the cause of this pain to be impingement of the patient's lower brachial plexus by the mammary prosthesis. Such a complication has not, to the authors' knowledge, been reported previously.

  20. Reliability, Readability and Quality of Online Information about Femoracetabular Impingement

    Directory of Open Access Journals (Sweden)

    Fatih Küçükdurmaz

    2015-07-01

    Conclusion: According to our results, the websites intended to attract patients searching for information regarding femoroacetabular impingement are providing a highly accessible, readable information source, but do not appear to apply a comparable amount of rigor to scientific literature or healthcare practitioner websites in regard to matters such as citing sources for information, supplying methodology and including a publication date. This indicates that while these resources are easily accessed by patients, there is potential for them to be a source of misinformation.

  1. MRI Evaluation of Femoroacetabular Impingement After Hip Preservation Surgery.

    Science.gov (United States)

    Li, Angela E; Jawetz, Shari T; Greditzer, Harry G; Burge, Alissa J; Nawabi, Danyal H; Potter, Hollis G

    2016-08-01

    This article reviews the surgical treatment options for femoroacetabular impingement (FAI), including labral repair and osteochondroplasty, and the expected postoperative appearance on MRI. Complications, including residual osseous deformities, chondral injury, adhesions, femoral neck stress fractures, osteonecrosis, instability, malpositioned suture anchors, and infection, will also be discussed. Knowledge of the surgical treatment of FAI can assist in improving our understanding of the expected postoperative MRI appearance and in evaluating surgical complications.

  2. Radiographic findings of femoroacetabular impingement in capoeira players.

    Science.gov (United States)

    Mariconda, Massimo; Cozzolino, Andrea; Di Pietto, Francesco; Ribas, Manuel; Bellotti, Vittorio; Soldati, Alessandra

    2014-04-01

    Capoeira is a Brazilian martial art that requires extreme movements of the hip to perform jumps and kicks. This study evaluated a group of capoeira players to assess the prevalence of femoroacetabular impingement (FAI) in athletes practicing this martial art. Twenty-four experienced capoeira players (14 men, 10 women) underwent a diagnostic assessment, including clinical examination and standard radiographs of the pelvis and hips. The α-angle, head-neck offset, crossover sign, acetabular index, lateral centre-edge angle, and the Tönnis grade were assessed using the radiographs. Clinical relationships for any radiographic abnormalities indicating FAI were also evaluated. Four subjects (17 %) reported pain in their hips. Forty-four hips (91.7 %) had at least one radiographic sign of CAM impingement, and 22 (45.8 %) had an α-angle of more than 60°. Eighteen hips (37.5 %) had at least one sign of pincer impingement and 16 (33.3 %) a positive crossover sign. Sixteen hips (33.3 %) had mixed impingement. There was a significant positive association between having an α-angle of more than 60° and the presence of groin pain (P = 0.002). A reduced femoral head-neck offset (P < 0.001) and an increased α-angle on the anteroposterior radiograph (P = 0.008) were independently associated with a higher Tönnis grade. High prevalence of radiographic CAM-type FAI among these skilled capoeira players was found. In these subjects, a negative clinical correlation for an increased α-angle was also detected. Additional caution should be exercised whenever subjects with past or present hip pain engage in capoeira.

  3. Apollo Video Photogrammetry Estimation Of Plume Impingement Effects

    Science.gov (United States)

    Immer, Christopher; Lane, John; Metzger, Philip T.; Clements, Sandra

    2008-01-01

    The Constellation Project's planned return to the moon requires numerous landings at the same site. Since the top few centimeters are loosely packed regolith, plume impingement from the Lander ejects the granular material at high velocities. Much work is needed to understand the physics of plume impingement during landing in order to protect hardware surrounding the landing sites. While mostly qualitative in nature, the Apollo Lunar Module landing videos can provide a wealth of quantitative information using modem photogrammetry techniques. The authors have used the digitized videos to quantify plume impingement effects of the landing exhaust on the lunar surface. The dust ejection angle from the plume is estimated at 1-3 degrees. The lofted particle density is estimated at 10(exp 8)- 10(exp 13) particles per cubic meter. Additionally, evidence for ejection of large 10-15 cm sized objects and a dependence of ejection angle on thrust are presented. Further work is ongoing to continue quantitative analysis of the landing videos.

  4. MRI for the preoperative evaluation of femoroacetabular impingement.

    Science.gov (United States)

    Li, Angela E; Jawetz, Shari T; Greditzer, Harry G; Burge, Alissa J; Nawabi, Danyal H; Potter, Hollis G

    2016-04-01

    Femoroacetabular impingement (FAI) refers to a condition characterized by impingement of the femoral head-neck junction against the acetabular rim, often due to underlying osseous and/or soft tissue morphological abnormalities. It is a common cause of hip pain and limited range of motion in young and middle-aged adults. Hip preservation surgery aims to correct the morphological variants seen in FAI, thereby relieving pain and improving function, and potentially preventing early osteoarthritis. The purpose of this article is to review the mechanisms of chondral and labral injury in FAI to facilitate an understanding of patterns of chondrolabral injury seen on MRI. Preoperative MRI evaluation of FAI should include assessment of osseous morphologic abnormalities, labral tears, cartilage status, and other associated compensatory injuries of the pelvis. As advanced chondral wear is the major relative contraindication for hip preservation surgery, MRI is useful in the selection of patients likely to benefit from surgery. Teaching points • The most common anatomical osseous abnormalities predisposing to FAI include cam and pincer lesions. • Morphological abnormalities, labral lesions, and cartilage status should be assessed. • In cam impingement, chondral wear most commonly occurs anterosuperiorly.• Pre-existing advanced osteoarthritis is the strongest predictor of poor outcomes after FAI surgery. • Injury to muscles and tendons or other pelvic structures can coexist with FAI.

  5. Shoulder impingement syndrome : evaluation of the causes with MRI

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong Ho; Song, In Sup; Chung, Hun Young; Yoon, Sang Jin; Kim, Yang Soo; Shim, Hyung Jin; Choi, Young Hee; Lee, Jong Beum; Lee, Yong Chul; Kim, Kun Sang [Chungang Univ. College of Medicine, Seoul (Korea, Republic of); Choi, Yun Sun [Eulji Hospital, College of Medicine, Seoul (Korea, Republic of)

    1999-12-01

    Various mechanical causes which induce shoulder impingement syndrome have been identified with the help of MRI. The aim of this study is to evaluate the incidence of such causes. A total of 54 patients with clinically confirmed shoulder impingement syndrome and a normal control group(n=20) without symptoms were included. We evaluated the incidence of hook shaped acromion, low lying acromion, downward slope of the acromion, subacromial spur, acromioclavicular joint hypertrophy, coracoacromial ligament hypertrophy, high cuff muscle bulk, and os acromiale. Among the 54 patients, the following conditions were present: acromioclavicular joint hypertrophy(n=36), coracoacromial ligament hypertrophy(n=20), subacromial spur(n=18), downward sloping of the acromion(n=16), hook shaped acromion(n=11), relatively high cuff muscle bulk(n=6), low lying acromion relative to the clavicle(n=3), and os acromiale(n=1). In the normal control group there were nine cases of acromioclavicular joint hypertrophy, nine of coracoacromial ligament hypertrophy, nine of downward sloping acromion, and three of low lying acromion, but hook shaped acromion, high cuff muscle bulk, and os acromiale were not found. Among 54 patients, the syndrome was due to five simultancous causes in one patient, four causes in two, three causes in 12, two causes in 22, and one cause in 17. Hook shaped acromion and subacromial spur are the statistically significant causes of shoulder impingement syndrome. In 69% of patients, the condition was due to more than one cause.

  6. Subacromial Impingement Syndrome Caused by a Voluminous Subdeltoid Lipoma

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Murray

    2014-01-01

    Full Text Available Subacromial impingement syndrome is a clinical diagnosis encompassing a spectrum of possible etiologies, including subacromial bursitis, rotator cuff tendinopathy, and partial- to full-thickness rotator cuff tears. This report presents an unusual case of subdeltoid lipoma causing extrinsic compression and subacromial impingement syndrome. The patient, a 60-year-old man, presented to our institution with a few years' history of nontraumatic, posteriorly localized throbbing pain in his right shoulder. Despite a well-followed 6-months physiotherapy program, the patient was still suffering from his right shoulder. The MRI scan revealed a well-circumscribed 6 cm × 2 cm × 5 cm homogenous lesion compatible with a subdeltoid intermuscular lipoma. The mass was excised en bloc, and subsequent histopathologic examination confirmed a benign lipoma. At 6-months follow-up, the patient was asymptomatic with a complete return to his activities. Based on this case and a review of the literature, a subacromial lipoma has to be included in the differential diagnosis of a subacromial impingement syndrome refractory to nonoperative treatment. Complementary imaging modalities are required only after a failed conservative management to assess the exact etiology and successfully direct the surgical treatment.

  7. Toward restrictions on boson stars as black hole mimickers

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, F S, E-mail: guzman@ifm.umich.mx [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C3, Cd. Universitaria, 58040 Morelia, Michoacan (Mexico)

    2011-09-22

    The status of boson stars as black hole mimickers is presented among other mimickers. We focus on the analysis of the emission spectrum of a simple accretion disk model. We describe the free parameters that allow a boson star to become a black hole mimicker and present an example of a particular astrophysical case.

  8. Effect of surface thickness on the wetting front velocity during jet impingement surface cooling

    Science.gov (United States)

    Agrawal, Chitranjan; Gotherwal, Deepesh; Singh, Chandradeep; Singh, Charan

    2017-02-01

    A hot stainless steel (SS-304) surface of 450 ± 10 °C initial temperature is cooled with a normally impinging round water jet. The experiments have been performed for the surface of different thickness e.g. 1, 2, 3 mm and jet Reynolds number in the range of Re = 26,500-48,000. The cooling performance of the hot test surface is evaluated on the basis of wetting front velocity. The wetting front velocity is determined for 10-40 mm downstream spatial locations away from the stagnation point. It has been observed that the wetting front velocity increase with the rise in jet flow rate, however, diminishes towards the downstream spatial location and with the rise in surface thickness. The proposed correlation for the dimensionless wetting front velocity predicts the experimental data well within the error band of ±30 %, whereas, 75 % of experimental data lies within the range of ±20 %.

  9. Soliton generation by internal tidal beams impinging on a pycnocline: laboratory experiments

    CERN Document Server

    Mercier, Matthieu J; Gostiaux, Louis; Gerkema, Theo; Magalhães, Jorge M; Da Silva, José C B; Dauxois, Thierry

    2015-01-01

    In this paper, we present the first laboratory experiments that show the generation of internal solitary waves by the impingement of a quasi-two-dimensional internal wave beam on a pycnocline. These experiments were inspired by observations of internal solitary waves in the deep ocean from synthetic aperture radar (SAR) imagery, where this so-called mechanism of 'local generation' was argued to be at work, here in the form of internal tidal beams hitting the thermocline. Nonlinear processes involved here are found to be of two kinds. First, we observe the generation of a mean flow and higher harmonics at the location where the principal beam reflects from the surface and pycnocline; their characteristics are examined using particle image velocimetry (PIV) measurements. Second, we observe internal solitary waves that appear in the pycnocline, detected with ultrasonic probes; they are further characterized by a bulge in the frequency spectrum, distinct from the higher harmonics. Finally, the relevance of our re...

  10. CFD analysis of rewetting vertical nuclear fuel rod by dispersed fluid jet impingement

    Directory of Open Access Journals (Sweden)

    Ajoy Debbarma

    2016-09-01

    Full Text Available Numerical analysis of cooling assessment in hot vertical fuel rod is carryout using ANSYS 14.0 – CFX Solver. Rewetting is the process of re-establishment of coolants with hot surfaces. Numerical validation exercise carried out with number of turbulence and shear stress turbulence model fairly predict the experimental data and used for further investigation. In the present paper, dispersed fluid is simulating with CFX solver to investigate the flow boiling process in emergency cooling of vertical fuel rod. When coolants come in contact on the hot surface this may not initiated the wetting patch. However, this paper introduces the unique jet impingement direction to remove the heat from the hot surface. In this report, the rewetting temperature and wetting delay also described during in progress of wetting front movement in hot vertical rod.

  11. Numerical Study of Impingement Location of Liquid Jet Poured from a Tilting Ladle with Lip Spout

    Science.gov (United States)

    Castilla, R.; Gamez-Montero, P. J.; Raush, G.; Khamashta, M.; Codina, E.

    2017-04-01

    A new approach for simulating liquid poured from a tilting lip spout is presented, using neither a dynamic mesh nor the moving solid solution method. In this case only the tilting ladle is moving, so we propose to rotate the gravitational acceleration at an angular velocity prescribed by a geometrical and dynamical calculation to keep the poured flow rate constant. This angular velocity is applied to modify the orientation of the gravity vector in computational fluid dynamics (CFD) simulations using the OpenFOAM® toolbox. Also, fictitious forces are considered. The modified solver is used to calculate the impingement location for six spout geometries and compare the jet dispersion there. This method could offer an inexpensive tool to calculate optimal spout geometries to reduce sprue size in the metal casting industry.

  12. Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications

    Science.gov (United States)

    Trinh, Huu P.; Bullard, Brad; Kopicz, Charles; Michaels, Scott

    2002-01-01

    To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concepts not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio (LD). This incentive can be translated to a convenience in the thrust chamber packaging. Variations of the vortex chamber concepts have been introduced in the past few decades. These investigations include an ongoing work at Orbital Technologies Corporation (ORBITEC). By injecting the oxidizer tangentially at the chamber convergence and fuel axially at the chamber head end, Knuth et al. were able to keep the wall relatively cold. A recent investigation of the low L/D vortex chamber concept for gel propellants was conducted by Michaels. He used both triplet (two oxidizer orifices and one fuel orifice) and unlike impinging schemes to inject propellants tangentially along the chamber wall. Michaels called the subject injection scheme an Impinging Stream Vortex Chamber (ISVC). His preliminary tests showed that high performance, with an Isp efficiency of 9295, can be obtained. MSFC and the U. S. Army are jointly investigating an application of the ISVC concept for the cryogenic oxygen/hydrocarbon propellant system. This vortex chamber concept is currently tested with gel propellants at AMCOM at Redstone Arsenal, Alabama. A version of this concept

  13. Diagnosis of shoulder impingement syndrome; Diagnostik des Schulterimpingementsyndroms

    Energy Technology Data Exchange (ETDEWEB)

    Hodler, J. [Orthopaedische Universitaetsklinik Balgrist, Zuerich (Switzerland)

    1996-12-01

    This article reviews the pathogenesis and clinical and imaging findings in shoulder impingement syndrome. Different stages of impingement syndrome are described. Stage I relates to edema and hemorrhage of the supraspinatus tendon. Stage II is characterized by bursal inflammation and fibrosis, as well as tendinopathy. In stage III there is a tear of the rotator cuff. Clinical signs many overlap. Moreover, calcifying tendinitis, fractures and pain originating from the cervical spine may mimic shoulder impingement syndrome. Imaging is important for the exact diagnosis. Standard radiographs are the basis of imaging in shoulder impingement syndrome. They may demonstrate subchondral sclerosis of the major tuberosity, subacromial spurs, and form anomalies of the acromion. They are also important in the differential diagnosis of shoulder impingement syndrome and demonstrate calcifying tendinitis, fractures and neoplasm. Ultrasonography has found acceptance as a screening tool and even as a final diagnostic method by many authors. However, there is a high interobserver variability in the demonstration of rotator cuff tears. Its usefulness has therefore been questioned. MR imaging is probably the method of choice in the evaluation of the rotator cuff and surrounding structures. Several investigations have demonstrated that differentiation of early findings, such as tendinopathy versus partial tears, may be difficult with MR imaging. However, reproducibility for fullthickness tears appears to be higher than for sonography. Moreover, specificity appears to be superior to sonography. MR arthrography is not universally accepted. However, it allows for more exact differentiation of discrete findings and may be indicated in preoperative planning. Standard arthrography and CT have a limited role in the current assessment of the rotator cuff. (orig.) [Deutsch] Grundlage des Impingementsyndroms ist eine Kompression des Supraspinatus am akromioklavikularen Bogen vor allem bei Flexion

  14. High-resolution hot-film measurement of surface heat flux to an impinging jet

    Science.gov (United States)

    O'Donovan, T. S.; Persoons, T.; Murray, D. B.

    2011-10-01

    To investigate the complex coupling between surface heat transfer and local fluid velocity in convective heat transfer, advanced techniques are required to measure the surface heat flux at high spatial and temporal resolution. Several established flow velocity techniques such as laser Doppler anemometry, particle image velocimetry and hot wire anemometry can measure fluid velocities at high spatial resolution (µm) and have a high-frequency response (up to 100 kHz) characteristic. Equivalent advanced surface heat transfer measurement techniques, however, are not available; even the latest advances in high speed thermal imaging do not offer equivalent data capture rates. The current research presents a method of measuring point surface heat flux with a hot film that is flush mounted on a heated flat surface. The film works in conjunction with a constant temperature anemometer which has a bandwidth of 100 kHz. The bandwidth of this technique therefore is likely to be in excess of more established surface heat flux measurement techniques. Although the frequency response of the sensor is not reported here, it is expected to be significantly less than 100 kHz due to its physical size and capacitance. To demonstrate the efficacy of the technique, a cooling impinging air jet is directed at the heated surface, and the power required to maintain the hot-film temperature is related to the local heat flux to the fluid air flow. The technique is validated experimentally using a more established surface heat flux measurement technique. The thermal performance of the sensor is also investigated numerically. It has been shown that, with some limitations, the measurement technique accurately measures the surface heat transfer to an impinging air jet with improved spatial resolution for a wide range of experimental parameters.

  15. Acoustic resolution photoacoustic Doppler velocimetry in blood-mimicking fluids

    Science.gov (United States)

    Brunker, Joanna; Beard, Paul

    2016-02-01

    Photoacoustic Doppler velocimetry provides a major opportunity to overcome limitations of existing blood flow measuring methods. By enabling measurements with high spatial resolution several millimetres deep in tissue, it could probe microvascular blood flow abnormalities characteristic of many different diseases. Although previous work has demonstrated feasibility in solid phantoms, measurements in blood have proved significantly more challenging. This difficulty is commonly attributed to the requirement that the absorber spatial distribution is heterogeneous relative to the minimum detectable acoustic wavelength. By undertaking a rigorous study using blood-mimicking fluid suspensions of 3 μm absorbing microspheres, it was discovered that the perceived heterogeneity is not only limited by the intrinsic detector bandwidth; in addition, bandlimiting due to spatial averaging within the detector field-of-view also reduces perceived heterogeneity and compromises velocity measurement accuracy. These detrimental effects were found to be mitigated by high-pass filtering to select photoacoustic signal components associated with high heterogeneity. Measurement under-reading due to limited light penetration into the flow vessel was also observed. Accurate average velocity measurements were recovered using “range-gating”, which furthermore maps the cross-sectional velocity profile. These insights may help pave the way to deep-tissue non-invasive mapping of microvascular blood flow using photoacoustic methods.

  16. Blood-Mimicking Fluid for Testing Ultrasonic Diagnostic Instrument

    Science.gov (United States)

    Tanaka, Kouhei; Yoshida, Tomoji; Sato, Kazuishi; Kondo, Toshio; Yasukawa, Kazuhiro; Miyamoto, Nobuaki; Taniguchi, Masahiko

    2012-07-01

    We present a blood-mimicking fluid (BMF) for the Doppler test object of medical diagnostic instruments. Accurate measurement in a flow Doppler test requires a BMF that has the acoustic velocity and density defined in the International Electrotechnical Commission (IEC) standard, and furthermore, they must be stable over time. To formulate a fluid with the desired density and acoustic velocity, we have developed a new fluid made of glycerine and water-soluble silicone oil. The new BMF includes dispersed polystyrene particles as scatterers. The density of the liquid can be adjusted to maintain it at the same value as that of the polystyrene particles, thus ensuring neutral buoyancy of the particles. The MBF was stable over a period of 2 weeks, during which the density and acoustic velocity did not change.

  17. The influence of the stagnation zone on the fluid dynamics at the nozzle exit of a confined and submerged impinging jet

    Science.gov (United States)

    Jeffers, Nicholas; Stafford, Jason; Conway, Ciaran; Punch, Jeff; Walsh, Edmond

    2016-02-01

    Low profile impinging jets provide a means to achieve high heat transfer coefficients while occupying a small quantity of space. Consequently, they are found in many engineering applications such as electronics cooling, annealing of metals, food processing, and others. This paper investigates the influence of the stagnation zone fluid dynamics on the nozzle exit flow condition of a low profile, submerged, and confined impinging water jet. The jet was geometrically constrained to a round, 16-mm diameter, square-edged nozzle at a jet exit to target surface spacing ( H/ D) that varied between 0.25 flow regimes is the main focus of this paper; however, laminar flow data are also presented between 1350 measurement facility was designed and commissioned to utilise particle image velocimetry in order to quantitatively measure the fluid dynamics both before and after the jet exits its nozzle. The velocity profiles are normalised with the mean velocity across the nozzle exit, and turbulence statistics are also presented. The primary objective of this paper is to present accurate flow profiles across the nozzle exit of an impinging jet confined to a low H/ D, with a view to guide the boundary conditions chosen for numerical simulations confined to similar constraints. The results revealed in this paper suggest that the fluid dynamics in the stagnation zone strongly influences the nozzle exit velocity profile at confinement heights between 0 0.5—where D is the inner diameter of the jet—in order to minimise modelling uncertainty.

  18. Spherical Boson Stars as Black Hole mimickers

    CERN Document Server

    Guzman, F S; 10.1103/PhysRevD.80.084023

    2010-01-01

    We present spherically symmetric boson stars as black hole mimickers based on the power spectrum of a simple accretion disk model. The free parameters of the boson star are the mass of the boson and the fourth order self-interaction coefficient in the scalar field potential. We show that even if the mass of the boson is the only free parameter it is possible to find a configuration that mimics the power spectrum of the disk due to a black hole of the same mass. We also show that for each value of the self-interaction a single boson star configuration can mimic a black hole at very different astrophysical scales in terms of the mass of the object and the accretion rate. In order to show that it is possible to distinguish one of our mimickers from a black hole we also study the deflection of light.

  19. Mimickers of breast malignancy on breast sonography.

    Science.gov (United States)

    Cho, So Hyun; Park, Sung Hee

    2013-11-01

    The aim of this article is to review benign breast lesions that can mimic carcinoma on sonography. Cases of benign lesions mimicking carcinoma on sonography were collected among lesions that were initially assessed as suspicious on sonography according to the American College of Radiology Breast Imaging Reporting and Data System category. Sonographically guided core needle biopsy was performed, and the pathologic types were confirmed to be benign. Cases of benign lesions mimicking carcinoma on sonography were shown to include fat necrosis, diabetic mastopathy, fibrocystic changes, sclerosing adenosis, ruptured inflammatory cysts, inflammatory abscesses, granulomatous mastitis, fibroadenomas, fibroadenomatous mastopathy, and apocrine metaplasia. Benign breast lesions may present with malignant features on imaging. A clear understanding of the range of appearances of benign breast lesions that mimic malignancy is important in radiologic-pathologic correlation to ensure that benign results are accepted when concordant with imaging and clinical features but, when discordant, there is no delay in further evaluation up to and including excisional biopsy.

  20. Cardiac sarcoidosis mimicking right ventricular dysplasia.

    Science.gov (United States)

    Shiraishi, Jun; Tatsumi, Tetsuya; Shimoo, Kazutoshi; Katsume, Asako; Mani, Hiroki; Kobara, Miyuki; Shirayama, Takeshi; Azuma, Akihiro; Nakagawa, Masao

    2003-02-01

    A 59-year-old woman with skin sarcoidosis was admitted to hospital for assessment of complete atrioventricular block. Cross-sectional echocardiography showed that the apical free wall of the right ventricle was thin and dyskinetic with dilation of the right ventricle. Thallium-201 myocardial imaging revealed a normal distribution. Both gallium-67 and technetium-99m pyrophosphate scintigraphy revealed no abnormal uptake in the myocardium. Right ventriculography showed chamber dilation and dyskinesis of the apical free wall, whereas left ventriculography showed normokinesis, mimicking right ventricular dysplasia. Cardiac sarcoidosis was diagnosed on examination of an endomyocardial biopsy specimen from the right ventricle. A permanent pacemaker was implanted to manage the complete atrioventricular block. After steroid treatment, electrocardiography showed first-degree atrioventricular block and echocardiography revealed an improvement in the right ventricular chamber dilation. Reports of cardiac sarcoidosis mimicking right ventricular dysplasia are extremely rare and as this case shows, right ventricular involvement may be one of its manifestations.

  1. Experimental and numerical investigations on the vortical structures of an impinging jet in crossflow%横流冲击射流涡旋结构的实验和数值研究

    Institute of Scientific and Technical Information of China (English)

    张燕

    2006-01-01

    @@ The objective of this dissertation is to investigate the impinging jet under the influence of crossflow.It has been known that there exist jet shear layer, impingement on the bottom wall, interactions between the induced wall jet and the ambient crossflow in near field.There are few intensive studies of the impinging jet in crossflow at home and abroad due to the complexities of flow, such as the formation and evolution of the vortical structures, interactions among vortices, while researches on the temporal and spatial evolution of these vortical structures can promote the practical applications in environment engineering, hydroelectricity engineering, etc., and provide the basis for flow control and improvement through revealing the inherent mechanism and development of the vortical structures.

  2. [Morgagni hernia mimicking intrathoracic lipomatous tumor].

    Science.gov (United States)

    Pinto, Carlos Silva; Bernardo, João; Eugénio, Luís; Antunes, Manuel J

    2013-01-01

    Morgagni hernia is the rarest type of diaphragmatic hernia, accounting for 2% of all cases. It consists in the thoracic protrusion of fat and/or abdominal viscera through a congenital defect in a retro or parasternal position. The clinical importance of this pathological entity is associated with the fact that it can be asymptomatic, mimicking other diseases, such as a large intrathoracic lipoma, as it happened in the case presented here. Incorrect diagnosis can cause catastrophic complications during surgery.

  3. Intradural extramedullary tuberculoma mimicking en plaque meningioma

    Directory of Open Access Journals (Sweden)

    Ozek Erdinc

    2009-01-01

    Full Text Available In this paper we report an 18 year old woman with an intradural extramedullary tuberculoma mimicking en plaque meningioma located in the thoracic region. The patient was operated via thoracic laminoplasty and tumor was totally resected. On the follow-up examination the magnetic resonance imaging demonstrated the total excision of the tumor. Here we describe a case of intradural extramedullary tuberculoma of the spinal cord as a complication of tuberculosis meningitis in a previously healthy young female.

  4. Benzalkonium Chloride Intoxication Mimicking Herpes Zoster Encephalitis

    OpenAIRE

    Güler, Ekrem; Olgar, Şeref; Davutoğlu, Mehmet; Garipardıç, Mesut; Karabiber, Hamza

    2011-01-01

    Benzalkonium chloride (BAC) is a frequently used disinfectant and its most well-known side effect is contact dermatitis. In this report, two children who had vesicular dermatitis, headache, lethargy, fever and encephalopathy mimicking Herpes zoster encephalitis were presented. Their consciousness level improved on the second day. From the medical history it was understood that the mother had applied 20% BAC solution to the scalps of two children. The aim of the presentation of this report is ...

  5. Benzalkonium Chloride Intoxication Mimicking Herpes Zoster Encephalitis

    OpenAIRE

    Ekrem Güler; Şeref Olgar; Mehmet Davutoğlu; Mesut Garipardıç; Hamza Karabiber

    2014-01-01

    Benzalkonium chloride (BAC) is a frequently used disinfectant and its most well-known side effect is contact dermatitis. In this report, two children who had vesicular dermatitis, headache, lethargy, fever and encephalopathy mimicking Herpes zoster encephalitis were presented. Their consciousness level improved on the second day. From the medical history it was understood that the mother had applied 20% BAC solution to the scalps of two children. The aim of the presentation of this report is...

  6. Hydroxychloroquine-Associated Hyperpigmentation Mimicking Elder Abuse

    OpenAIRE

    Cohen, Philip R

    2013-01-01

    Background Hydroxychloroquine may result in cutaneous dyschromia. Older individuals who are the victims of elder abuse can present with bruising and resolving ecchymoses. Purpose The features of hydroxychloroquine-associated hyperpigmentation are described, the mucosal and skin manifestations of elder abuse are reviewed, and the mucocutaneous mimickers of elder abuse are summarized. Case Report An elderly woman being treated with hydroxychloroquine for systemic lupus erythematosus developed d...

  7. Intra-abdominal gout mimicking pelvic abscess

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chia-Hui; Chen, Clement Kuen-Huang [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (Taiwan); National Yang-Ming University, School of Medicine, Taipei (Taiwan); Yeh, Lee-Ren; Pan, Huay-Ban; Yang, Chien-Fang [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (Taiwan)

    2005-04-01

    Gout is the most common crystal-induced arthritis. Gouty tophi typically deposit in the extremities, especially toes and fingers. We present an unusual case of intrapelvic tophaceous gout in a patient suffering from chronic gouty arthritis. CT and MRI of the abdomen and pelvic cavity disclosed calcified gouty tophi around both hips, and a cystic lesion with peripheral enhancement in the pelvic cavity along the course of the iliopsoas muscle. The intra-abdominal tophus mimicked pelvic abscess. (orig.)

  8. Intracranial capillary hemangioma mimicking a dissociative disorder

    Directory of Open Access Journals (Sweden)

    Alexander Lacasse

    2012-01-01

    Full Text Available Capillary hemangiomas, hamartomatous proliferation of vascular endothelial cells, are rare in the central nervous system (CNS. Intracranial capillary hemangiomas presenting with reversible behavioral abnormalities and focal neurological deficits have rarely been reported. We report a case of CNS capillary hemangioma presenting with transient focal neurological deficits and behavioral abnormalities mimicking Ganser’s syndrome. Patient underwent total excision of the vascular malformation, resulting in complete resolution of his symptoms.

  9. Optimization of a GO2/GH2 Impinging Injector Element

    Science.gov (United States)

    Tucker, P. Kevin; Shyy, Wei; Vaidyanathan, Rajkumar

    2001-01-01

    An injector optimization methodology, method i, is used to investigate optimal design points for a gaseous oxygen/gaseous hydrogen (GO2/GH2) impinging injector element. The unlike impinging element, a fuel-oxidizer- fuel (F-O-F) triplet, is optimized in terms of design variables such as fuel pressure drop, (Delta)P(sub f), oxidizer pressure drop, (Delta)P(sub o), combustor length, L(sub comb), and impingement half-angle, alpha, for a given mixture ratio and chamber pressure. Dependent variables such as energy release efficiency, ERE, wall heat flux, Q(sub w), injector heat flux, Q(sub inj), relative combustor weight, W(sub rel), and relative injector cost, C(sub rel), are calculated and then correlated with the design variables. An empirical design methodology is used to generate these responses for 163 combinations of input variables. Method i is then used to generate response surfaces for each dependent variable. Desirability functions based on dependent variable constraints are created and used to facilitate development of composite response surfaces representing some, or all, of the five dependent variables in terms of the input variables. Three examples illustrating the utility and flexibility of method i are discussed in detail. First, joint response surfaces are constructed by sequentially adding dependent variables. Optimum designs are identified after addition of each variable and the effect each variable has on the design is shown. This stepwise demonstration also highlights the importance of including variables such as weight and cost early in the design process. Secondly, using the composite response surface which includes all five dependent variables, unequal weights are assigned to emphasize certain variables relative to others. Here, method i is used to enable objective trade studies on design issues such as component life and thrust to weight ratio. Finally, specific variable weights are further increased to illustrate the high marginal cost of

  10. MAGNETIC RESONANCE IMAGING EVALUATION OF ROTATOR CUFF IMPINGEMENT

    Directory of Open Access Journals (Sweden)

    Chandrakanth K. S

    2017-06-01

    Full Text Available BACKGROUND Shoulder pain is a common clinical problem. Impingement syndrome of the shoulder is believed to be the most common cause of shoulder pain. The term ‘impingement syndrome’ was first used by Neer to describe a condition of shoulder pain associated with chronic bursitis and partial thickness tear of Rotator Cuff (RC. The incidence of Rotator Cuff (RC tear is estimated to be about 20.7% in the general population. This study is intended to analyse various extrinsic and intrinsic causes of shoulder impingement. MATERIALS AND METHODS 110 consecutive patients referred for MRI with clinical suspicion of shoulder impingement were prospectively studied. All the patients were evaluated for Rotator Cuff (RC degeneration and various extrinsic factors that lead to degeneration like acromial shape, down-sloping acromion, Acromioclavicular (AC joint degeneration and acromial enthesophyte. Intrinsic factors like degeneration and its correlation with age of the patients were evaluated. RESULTS Of the total 110 patients, 19 (17.3% patients had FT RC tear and 31 (28.2% had PT (both bursal and articular surface tears. There was no statistically significant correlation (p=0.76 between acromion types and RC tear. Down-sloping acromion and enthesophytes had statistically significant association with RC tear (p=0.008 and 0.008, respectively. Statistically significant (0.008 correlation between the severity of AC joint degeneration and RC tears was noted. AC joint degeneration and RC pathologies also showed a correlation with the age of the patients with p values of <0.001 and 0.001, respectively. CONCLUSION No statistically significant correlation between RC pathologies with hooked acromion was found, that makes the role played by hooked acromion in FT RC tear questionable. AC joint degeneration association with RC tear is due to the association of both RC tear and AC joint degeneration with age of the patient. Down-sloping acromion, AC joint degeneration

  11. Wall jets created by single and twin high pressure jet impingement

    Science.gov (United States)

    Miller, P.; Wilson, M.

    1993-03-01

    An extensive experimental investigation into the nature of the wall jets produced by single and twin normal jet impingement has been undertaken. Wall jet velocity profiles have been recorded up to 70 jet diameters from the impingement point, at pressures representative of current VStol technology. The tests used fixed convergent nozzles, with nozzle height and spacing and jet pressure being varied. Single jet impingement displays a consistent effect of nozzle height on wall jet development. For twin jet cases a powerful reinforcement exists along the wall jet interaction plane. Remote from the interaction plane the wall jets are weaker than those produced by a single jet impingement.

  12. Numerical simulation of liquid-layer breakup on a moving wall due to an impinging jet

    Science.gov (United States)

    Yu, Taejong; Moon, Hojoon; You, Donghyun; Kim, Dokyun; Ovsyannikov, Andrey

    2014-11-01

    Jet wiping, which is a hydrodynamic method for controlling the liquid film thickness in coating processes, is constrained by a rather violent film instability called splashing. The instability is characterized by the ejection of droplets from the runback flow and results in an explosion of the film. The splashing phenomenon degrades the final coating quality. In the present research, a volume-of-fluid (VOF)-based method, which is developed at Cascade Technologies, is employed to simulate the air-liquid multiphase flow dynamics. The present numerical method is based on an unstructured-grid unsplit geometric VOF scheme and guarantees strict conservation of mass of two-phase flow, The simulation results are compared with experimental measurements such as the liquid-film thickness before and after the jet wiping, wall pressure and shear stress distributions. The trajectories of liquid droplets due to the fluid motion entrained by the gas-jet operation, are also qualitatively compared with experimental visualization. Physical phenomena observed during the liquid-layer breakup due to an impinging jet is characterized in order to develop ideas for controlling the liquid-layer instability and resulting splash generation and propagation. Supported by the Grant NRF-2012R1A1A2003699, the Brain Korea 21+ program, POSCO, and 2014 CTR Summer Program.

  13. Simulations of impinging droplets with surfactant-dependent dynamic contact angle

    Science.gov (United States)

    Ganesan, Sashikumaar

    2015-11-01

    An arbitrary Lagrangian-Eulerian (ALE) finite element scheme for computations of soluble surfactant droplet impingement on a horizontal surface is presented. The numerical scheme solves the time-dependent Navier-Stokes equations for the fluid flow, scalar convection-diffusion equation for the surfactant transport in the bulk phase, and simultaneously, surface evolution equations for the surfactants on the free surface and on the liquid-solid interface. The effects of surfactants on the flow dynamics are included into the model through the surface tension and surfactant-dependent dynamic contact angle. In particular, the dynamic contact angle (θd) of the droplet is defined as a function of the surfactant concentration at the contact line and the equilibrium contact angle (θe0) of the clean surface using the nonlinear equation of state for surface tension. Further, the surface forces are included into the model as surface divergence of the surface stress tensor that allows to incorporate the Marangoni effects without calculating the surface gradient of the surfactant concentration on the free surface. In addition to a mesh convergence study and validation of the numerical results with experiments, the effects of adsorption and desorption surfactant coefficients on the flow dynamics in wetting, partially wetting and non-wetting droplets are studied in detail. It is observed that the effects of surfactants are more in wetting droplets than in the non-wetting droplets. Further, the presence of surfactants at the contact line reduces the equilibrium contact angle further when θe0 is less than 90°, and increases it further when θe0 is greater than 90°. Nevertheless, the presence of surfactants has no effect on the contact angle when θe0 = 90 °. The numerical study clearly demonstrates that the surfactant-dependent contact angle has to be considered, in addition to the Marangoni effect, in order to study the flow dynamics and the equilibrium states of surfactant

  14. Application of a novel type impinging streams reactor in solid-liquid enzyme reactions and modeling of residence time distribution using GDB model.

    Science.gov (United States)

    Fatourehchi, Niloufar; Sohrabi, Morteza; Dabir, Bahram; Royaee, Sayed Javid; Haji Malayeri, Adel

    2014-02-01

    Solid-liquid enzyme reactions constitute important processes in biochemical industries. The isomerization of d-glucose to d-fructose, using the immobilized glucose isomerase (Sweetzyme T), as a typical example of solid-liquid catalyzed reactions has been carried out in one stage and multi-stage novel type of impinging streams reactors. Response surface methodology was applied to determine the effects of certain pertinent parameters of the process namely axial velocity (A), feed concentration (B), nozzles' flow rates (C) and enzyme loading (D) on the performance of the apparatus. The results obtained from the conversion of glucose in this reactor were much higher than those expected in conventional reactors, while residence time was decreased dramatically. Residence time distribution (RTD) in a one-stage impinging streams reactor was investigated using colored solution as the tracer. The results showed that the flow pattern in the reactor was close to that in a continuous stirred tank reactor (CSTR). Based on the analysis of flow region in the reactor, gamma distribution model with bypass (GDB) was applied to study the RTD of the reactor. The results indicated that RTD in the impinging streams reactor could be described by the latter model.

  15. Current UK practices in the management of subacromial impingement

    Science.gov (United States)

    Drury, Colin; Tait, Gavin R

    2015-01-01

    Background Controversy presently exists surrounding the management of patients with subacromial impingement. This study aims to highlight current UK practices in the management of these patients. Methods BESS members were invited to complete a questionnaire and responses were received from 157 consultant shoulder surgeons. Results Physiotherapy is an integral part of management for 93% of surgeons with a minimum period of 12 weeks being most popular prior to consideration of arthroscopic subacromial decompression. Subacromial steroid injection is used by 95% and 86% repeat this if the patient has failed to respond to a previous injection by the general practioner. From initial presentation, 77% felt there should be at least 3 months of conservative management before proceeding to surgery. Good but transient response to subacromial injection was considered the best predictor of good surgical outcome by 77%. The coracoacromial ligament is fully released by 78%, although there was greater variation in how aggressive surgeons were with acromioplasty. Most (59%) do not include the nontender acromioclavicular joint to any extent in routine acromioplasty. Hospital physiotherapy protocols are used by 63% for postoperative rehabilitation. Conclusions Variation exists in the management regimes offered to patients with subacromial impingement, but most employ a minimum period of 12 weeks of conservative management incorporating physiotherapy and at least 2 subacromial steriod injections. PMID:27582972

  16. Laser impingement on bare and encased high explosives: safety limits

    Energy Technology Data Exchange (ETDEWEB)

    Roeske, F

    1999-03-15

    During the course of experiments involving high explosives, (HE), alignment lasers are often employed where the laser beam impinges upon a metal encased HE sample or on the bare HE itself during manned operations. While most alignment lasers are of low enough power so as not to be of concern, safety questions arise when considering the maximum credible power output of the laser in a failure mode, or when multiple laser spots are focused onto the experiment simultaneously. Safety questions also arise when the focused laser spot size becomes very small, on the order of 100 {micro}m or less. This paper addresses these concerns by describing a methodology for determining safety margins for laser impingement on metal encased HE as well as one for bare HE. A variety of explosives encased in Al, Cu, Ta and stainless steel were tested using the first of these techniques. Additional experiments were performed using the second method where the laser beam was focused directly on eight different samples of pressed-powder HE.

  17. Impingement of hollow cone spray on hot porous medium

    Institute of Scientific and Technical Information of China (English)

    Zhiguo ZHAO; Maozhao XIE

    2008-01-01

    To have a good understanding of the formation of homogenous mixture in a porous medium engine, the interaction between hollow cone spray and hot porous med-ium was studied numerically by using an improved version of KIVA-3V code. The improved KIVA-3V code is incor-porated with an impingement model, heat transfer model and linearized instability sheet atomization (LISA) model to simulate the hollow cone spray. The reasonability of the impingement model and heat transfer model was validated. With a simple model to describe the structure of the porous medium, the interaction between hollow cone spray and hot porous medium was simulated under different ambient pressures and spray cone angles. Computational results show that the fuel spray could be divided into smaller ones, which provides conditions for the quick evaporation of fuel droplets and the mixing of fuel vapor with air. Differences in ambient pressure and spray cone angle affect the distri-bution of droplets in the porous medium.

  18. Nontraumatic glenohumeral instability and coracoacromial impingement in swimmers.

    Science.gov (United States)

    Bak, K

    1996-06-01

    Competitive swimming is one of the most demanding and time-consuming sports. Swimmers at elite level practice 20-30 h per week. During 1 year's practice, the average top level swimmer performs more than 500,000 stroke revolutions per arm. These innumerable repetitions over many years of hard training together with an increasing muscular imbalance around the shoulder girdle seem to be the main etiological factors in the development of the over-use syndrome swimmer's shoulder. Shoulder pain in swimmers has in general been regarded as synonymous with coracoacromial impingement, i.e. anterior shoulder pain due to rotator cuff tendinitis, but new knowledge suggests that a concomitant glenohumeral instability plays an additional role. The diagnostic complexity of the problem is as challenging as the search for the gold standard of treatment. The condition should ideally be diagnosed as early as possible, and intensive functional rehabilitation of the shoulder girdle including the scapular muscles should be started in order to restore muscle balance. The surgical possibilities include subacromial decompression in cases of purely mechanical impingement. If a painful glenohumeral instability persists after intensive functional rehabilitation, anterior capsulolabral reconstruction can be performed. Still, however, short- and long-term results show that surgery is less successful in elite athletes involved in overhead sports. Prevention protocols include education of coaches in primary injury prophylaxis and the institution of resistance strength training in prepubescent swimmers. Emphasis should be made to improve muscular balance around the glenohumeral and scapulothoracic joints.

  19. Pulmonary tumour microembolism clinically mimicking alveolitis

    Science.gov (United States)

    Lo, A W I; Tse, G M K; Chu, W C W; Chan, A B W

    2003-01-01

    A 56 year old man with previously unsuspected recurrence of squamous cell carcinoma of the oesophagus presented with dyspnoea. Bronchoscopy and computed tomography suggested bronchopneumonic changes with an infectious cause. He suffered a rapidly deteriorating course and died despite active treatment, including antibiotics and mechanical ventilation. Necropsy revealed a florid pulmonary tumour microembolism mimicking alveolitis. No bronchopneumonia was seen. The emboli arose from loosely attached tumour vegetations in the tricuspid valve. In a patient with known malignancy, tumour microembolism should be considered as an uncommon cause of rapid respiratory failure, refractory to antibiotic treatment. PMID:14600135

  20. Hypertrophic Nonunion Humerus Mimicking an Enchondroma

    Directory of Open Access Journals (Sweden)

    N. K. Magu

    2014-01-01

    Full Text Available Introduction. Although fractures of humeral shaft show excellent results with conservative management, nonunion does occur. Case Report. We bring forth the case of a young male with a 1.5-year-old hypertrophic nonunion of the humerus mimicking an enchondroma. The initial X-ray images of the patient appeared to be an enchondroma, which only on further evaluation and histopathological analysis was diagnosed conclusively to be a hypertrophic nonunion. Discussion. Enchondromas are often incidentally diagnosed benign tumours. It is however not common to misdiagnose a hypertrophic nonunion to be an enchondroma. We present this case to highlight the unique diagnostic dilemma the treating team had to face.

  1. Benzalkonium Chloride Intoxication Mimicking Herpes Zoster Encephalitis

    Directory of Open Access Journals (Sweden)

    Ekrem Güler

    2011-06-01

    Full Text Available Benzalkonium chloride (BAC is a frequently used disinfectant and its most well-known side effect is contact dermatitis. In this report, two children who had vesicular dermatitis, headache, lethargy, fever and encephalopathy mimicking Herpes zoster encephalitis were presented. Their consciousness level improved on the second day. From the medical history it was understood that the mother had applied 20% BAC solution to the scalps of two children. The aim of the presentation of this report is to draw attention to the fact that BAC application to the scalp for treating pediculosis capitis may resemble the herpes encephalitis clinical picture.

  2. Acute Myopericarditis Mimicking Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Seval İzdeş

    2011-08-01

    Full Text Available Acute coronary syndromes among young adults are relatively low when compared with older population in the intensive care unit. Electrocardiographic abnormalities mimicking acute coronary syndromes may be caused by non-coronary syndromes and the differential diagnosis requires a detailed evaluation. We are reporting a case of myopericarditis presenting with acute ST elevation and elevated cardiac enzymes simulating acute coronary syndrome. In this case report, the literature is reviewed to discuss the approach to distinguish an acute coronary syndrome from myopericarditis. (Journal of the Turkish Society Intensive Care 2011; 9:68-70

  3. Central skeletal sarcoidosis mimicking metastatic disease

    Energy Technology Data Exchange (ETDEWEB)

    Talmi, Danit; Smith, Stacy; Mulligan, Michael E. [University of Maryland School of Medicine, Department of Radiology, Baltimore, MD (United States)

    2008-08-15

    Sarcoidosis is a systemic disease that histologically typically shows non-caseating granulomas. The most common radiologic finding is hilar and mediastinal adenopathy. Patients with widely disseminated disease may show involvement of the peripheral appendicular skeleton in 1-13% of such cases. A primary skeletal presentation without other manifestations typical of the disease is rare. We present a case of sarcoidosis in a middle-aged Caucasian man in whom the disease presented with widespread lytic lesions in the axial skeleton and long bones, mimicking metastatic disease. There was no involvement of the peripheral skeleton, skin or lungs. (orig.)

  4. Immunoglobulin G4-Related Disease Mimicking Asthma

    Directory of Open Access Journals (Sweden)

    Hiroshi Sekiguchi

    2013-01-01

    Full Text Available Immunoglobulin (Ig G4-related disease (also known as ‘IgG4-related sclerosing disease’, ‘IgG4-related systemic disease’ or ‘hyper-IgG4-disease’ is a recently recognized systemic fibroinflammatory disease associated with IgG4-positive plasma cells in tissue lesions. IgG4-related disease was initially described as autoimmune pancreatitis, but it is now known to affect virtually any organ. The authors describe a patient presenting with multi-organ manifestations, including airway inflammation mimicking asthma, pulmonary parenchymal infiltrates, intrathoracic lymphadenopathy, submandibular gland swelling and a kidney mass.

  5. Remote Cutaneous Breast Carcinoma Metastasis Mimicking Dermatitis

    Directory of Open Access Journals (Sweden)

    Annakan V Navaratnam

    2015-01-01

    Full Text Available Cutaneous metastases from primary internal malignancies are an uncommon presentation. Cutaneous metastases are more frequently seen in breast cancer than in any other visceral malignancy in women. Medical practitioners should be vigilant of the possibility of unusual presentations of metastatic disease in breast cancer patients with lobular carcinoma presenting as cutaneous lesions mimicking benign dermatological conditions. Herein, we present a case of a 75-year-old woman presenting with cutaneous lobular breast carcinoma metastases on her anterior right leg, which had previously been misdiagnosed as dermatitis for 9 years.

  6. Delayed traumatic diaphragmatic hernia mimicking hydropneumothorax

    Directory of Open Access Journals (Sweden)

    Rachna Wadhwa

    2014-01-01

    Full Text Available Traumatic diaphragmatic hernia (TDH is generally a consequence of thoraco-abdominal trauma. Anaesthetic problems arise due to herniation of abdominal contents into the thoracic cavity causing diaphragmatic dysfunction, lung collapse, mediastinal shift and haemodynamic instability. Diagnosis depends on history, clinical signs and radiological investigations. Sometimes, it may be misdiagnosed as hydropneumothorax due to the presence of air and fluid in the viscera lying in the pleural cavity. We report a case of TDH mimicking hydropneumothorax on radiological investigations and subsequent surgical management, which led to serious complications.

  7. Brucellosis in spondyloarthritis mimicking an exacerbation.

    Science.gov (United States)

    Garip, Y; Eser, F; Erten, S; Yilmaz, O; Yildirim, P

    2014-01-01

    Spondyloarthritis are a group of chronic inflammatory diseases that affect the axial skeleton, entheses and peripheral joints and may have extraarticular manifestations such as uveitis, psoriasis and inflammatory bowel disease. Brucellosis is a systemic infectious disease, endemic in Middle East, Latin America, and Mediterranean countries, which may present manifestations that resemble other diseases posing serious problems of differential diagnosis. Some hallmarks of Brucellosis may mimic a spondyloarthritis flare. In this paper, authors present a clinical case of brucellosis occurring in a patient with spondyloarthritis. Clinical symptoms initially mimicked exacerbation of spondyloarthritis.

  8. Post-pancreatitis Fat Necrosis Mimicking Carcinomatosis.

    Science.gov (United States)

    Smith, Joshua P; Arnoletti, J Pablo; Varadarajulu, Shyam; Morgan, Desiree E

    2008-01-01

    Acute pancreatitis can result in retroperitoneal fat necrosis, typically occurring in the peripancreatic region, with extension into the transverse mesocolon, omentum and mesenteric root. When evaluated with contrast enhanced computed tomography (CECT), acute peripancreatic post necrotic collections typically become lower in attenuation over time, and often appear as homogeneous fluid collections. Saponification as a complication of fat necrosis in patients with acute pancreatitis is a well recognized clinical entity. While retroperitonal fat necrosis is commonly seen on CECT, saponification is not a prominent imaging feature. We present a case of acute pancreatitis complicated by extensive saponification of fat throughout the retroperitoneum and peritoneal lining, mimicking carcinomatosis.

  9. Severe emphysematous pyelonephritis mimicking intestinal obstruction.

    Science.gov (United States)

    Sun, Ji Ning; Zhang, Bao Long; Yu, Hai Yan; Wang, Bin

    2015-12-01

    Emphysematous pyelonephritis is a severe necrotizing infection characterized by the presence of gas and/or fluid in the renal parenchyma, collecting system, or perirenal tissues. Emphysematous pyelonephritis with approximately 15 cm air-fluid level, diffused ureteral involvement, and the accumulation of gas in liver and peritoneal cavity is very rare. Here, we reported a severe emphysematous pyelonephritis with multiple huge air-fluid level mimicking intestinal obstruction and with the accumulation of gas in liver and ureter in computed tomography imaging. The patient was successfully managed by percutaneous nephrostomy combined with medical treatment.

  10. Investigation of heat transfer processes involved liquid impingement jets: a review

    Directory of Open Access Journals (Sweden)

    M. Molana

    2013-09-01

    Full Text Available This review reports research on liquid impingement jets and the abilities, limitations and features of this method of heat transfer. Some available and important correlations for Nusselt number are collected here. Also we demonstrate the capability of nanofluids to be applied in heat transfer processes involved liquid impingement jets.

  11. Wenzel to Cassie transition during droplet impingement on a superhydrophobic surface

    Science.gov (United States)

    Clavijo, Cristian E.; Crockett, Julie; Maynes, Daniel

    2016-11-01

    Superhydrophobic surfaces offer many industrial advantages such as drag reduction and self-cleaning behavior as long as the liquid remains suspended above the composite solid/gas interface (Cassie state). These advantages are hindered when liquid penetrates the gas cavities (Wenzel state), and this is commonly referred to as impalement. Current efforts to drive impaled liquid out of, or dewet, the cavities—such as boiling or mechanical vibrations—are locally disruptive to the flow. In this work, we reveal that passive dewetting is possible during droplet impingement on micropillar substrates under the right thermodynamical conditions. Exploration included substrates with pillar-to-pillar spacing of 8 and 16 μ m , pillar diameters of 3 and 6 μ m , and pillar heights of 4 to 8 μ m and 8 to 18 μ m , respectively. The substrate temperature range considered was 23 mechanism are formulated based on evaporation and surface energy. First-order models are consequently constructed, revealing that dewetting does not occur due to evaporation, but is caused by surface energy gradients at the interface. Dissipation in the flow is taken into account due to hydrodynamic and nonhydrodynamic mechanisms; the latter is found to dominate resistance.

  12. HEAT TRANSFER PERFORMANCE OF AN OIL JET IMPINGING ON A DOWNWARD-FACING STAINLESS STEEL PLATE

    Directory of Open Access Journals (Sweden)

    Roy J Issa

    2011-01-01

    Full Text Available An experimental study is carried out for the quenching of a stainless steel plate using a single oil jet impinging on the bottom surface of the plate. The objective of this study is to investigate the effect of the oil jet flow operating conditions onto the heat transfer effectiveness when the plate is heated to temperatures ranging from around 115 to 630 oC, and the oil is heated to temperatures ranging from 60 to 75 oC. Tests are conducted on the oil at various temperatures to determine its viscosity. Experiments are conducted for nozzle exit flow rates ranging from 113 to 381 ml/min, oil jet pressures from 3.1 to 12 psi, and nozzle-to-plate surface distances of 0.6 and 1 cm. The variation of the oil heat flux and heat transfer coefficient with the surface temperature for the different quenching parameters is calculated from the acquired temperature data. Tests results show the oil heat transfer effectiveness keeps increasing for increasing plate temperature. Oil jet pressure is shown to have a considerable effect on the oil heat transfer, while the nozzle-to-plate surface distance is shown to have a lesser effect. The results of this study shall lead to a better understanding of the parameters that play an important role in oil quenching for applications that are of interest to the metal process industry.

  13. Study on diesel cylinder-head cooling using nanofluid coolant with jet impingement

    Directory of Open Access Journals (Sweden)

    Su Zhong-Gen

    2015-01-01

    Full Text Available To improve the heat-transfer performance of a diesel-engine cylinder head, nanofluid coolant as a new fluid was investigated, and jet impingement technology was then used to study on how to better improve heat-transfer coefficient at the nose bridge area in the diesel-engine cylinder head. Computational fluid dynamic simulation and experiments results demonstrated that using the same jet impingement parameters, the different volume shares of nanofluids showed better cooling effect than traditional coolant, but the good effect of the new cooling method was unsuitable for high volume share of nanofluid. At the same volume share of nanofluid, different jet impingement parameters such as jet angles showed different heat-transfer performance. This result implies that a strong association exists between jet impingement parameters and heat-transfer coefficient. The increase in coolant viscosity of the nanofluid coolant using jet impingement requires the expense of more drive-power cost.

  14. Methods for obtaining and reducing experimental droplet impingement data on arbitrary bodies

    Science.gov (United States)

    Papadakis, Michael; Elangovan, R.; Freund, George A., Jr.; Breer, Marlin D.

    1991-01-01

    Experimental water droplet impingement data are used to validate particle trajectory computer codes used in the analysis and certification of aircraft de-icing/anti-icing systems. Water droplet impingement characteristics of aerodynamic surfaces are usually obtained from wind-tunnel dye tracer experiments. This paper presents a dye tracer method for measuring water droplet impingement characteristics on arbitrary geometries and a new data reduction method, based on laser reflectance measurements, for extracting impingement data. Extraction of impingement data has been a very time-consuming process in the past. The new data reduction method developed is at least an order of magnitude more efficient than the method previously used. The accuracy of the method is discussed and results obtained are presented.

  15. Immunohistological analysis of extracted anterior cruciate ligament graft impinged against posterior cruciate ligament

    Directory of Open Access Journals (Sweden)

    Kato So

    2011-11-01

    Full Text Available Abstract A young female athlete suffered from the residual instability of the knee after anterior cruciate ligament (ACL reconstruction with hamstring autograft. The 3-dimensional (3-D CT scan showed the "high noon" positioning of the primary femoral bone tunnel. The revision surgery with anatomic double-bundle technique was performed two years after the primary surgery and the femoral tunnels were created with the assistance of the 3-D fluoroscopy-based navigation. An arthroscopic examination confirmed the ACL graft impingement against posterior cruciate ligament (PCL when the knee was deeply flexed. The histological analysis of the resected primary ACL graft showed local inflammatory infiltration, enhanced synovial coverage and vascularization at the impinged site. The enhanced expression of vascular endothelial growth factor (VEGF at the impinged area when compared with non-impinged area was observed on immunohistochemical analysis. Abnormal mechanical stress by the impingement against PCL might have induced chronic inflammation and VEGF overexpression.

  16. Mimicked Web Page Detection over Internet

    Directory of Open Access Journals (Sweden)

    Y. Narasimha Rao

    2014-01-01

    Full Text Available Phishing is process of steeling valuable information such as ATM pins, Credit card details over internet. Where the attacker creates mimicked web pages from the legitimate web pages to fool users. In this paper, we propose an effective anti-phishing solution, by combining image based visual similarity based approach to detect plagiarized web pages. We used effective algorithms for our detection mechanism, speeded up Robust Features (SURF algorithm in order to generate signature based on extracting stable key points from the screen shot of the web page. When a legitimate web page is registered with our system, this algorithm applied on that web page in order to generate signatures, and these signatures are stored in the database for our trained system. When there is a suspected web page, this algorithm is applied to generate both the signatures of the suspected page and is verified against our database of corresponding legitimate web pages. Our results verified that our proposed system is very effective to detect the mimicked web pages with minimal false positives

  17. Doxycycline-induced ulceration mimicking esophageal cancer

    Science.gov (United States)

    Tahan, Veysel; Sayrak, Hakan; Bayar, Nevzat; Erer, Burak; Tahan, Gulgun; Dane, Faysal

    2008-01-01

    Introduction Doxycycline-induced esophageal ulcer patients are mostly young persons with no history of esophageal dysfunction. Heartburn, midsternal pain and dysphagia are the most common symptoms. It has generally a benign course. The present case is the first report of doxycycline-induced extensive ulcerations, mimicking esophageal cancer in two esophageal segments alongside, in the literature. Case presentation This report describes a 16-year-old Caucasian girl who, while taking doxycycline capsules100 mg twice a day for acne vulgaris for 3 months, developed these symptoms. An upper endoscopy revealed multiple circumferential deep ulcerations surrounding fragile, irregular, hyperemic and hypertrophic mucosa at the level of the mid-esophagus and concomitantly in the lower esophageal sphincter. The lesions were biopsied to exclude esophageal carcinoma because of the suspicious appearance in the endoscopic examination. The histopathological examination, haematoxylin and eosin stained sections showed ulceration with a mixed inflammatory infiltrate. Doxycycline was discontinued and she was given sucralfate 1 g qid and omeprazole 20 mg bid orally. All symptoms of the patient were resolved on the third day of the treatment. After 4 weeks of the therapy, an upper endoscopic control examination demonstrated normal findings. Conclusion The present case has been an uncommon presentation of doxycycline-induced extensive ulcerations, mimicking esophageal cancer in two esophageal segments, concomitantly. Even the lesions were biopsied to exclude esophageal carcinoma. A modification on the behavior of taking drugs can prevent these unpleasant complications. PMID:18778470

  18. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as solidif......Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... as solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

  19. Clinical and Histologic Mimickers of Celiac Disease.

    Science.gov (United States)

    Kamboj, Amrit K; Oxentenko, Amy S

    2017-08-17

    Celiac disease is an autoimmune disorder of the small bowel, classically associated with diarrhea, abdominal pain, and malabsorption. The diagnosis of celiac disease is made when there are compatible clinical features, supportive serologic markers, representative histology from the small bowel, and response to a gluten-free diet. Histologic findings associated with celiac disease include intraepithelial lymphocytosis, crypt hyperplasia, villous atrophy, and a chronic inflammatory cell infiltrate in the lamina propria. It is important to recognize and diagnose celiac disease, as strict adherence to a gluten-free diet can lead to resolution of clinical and histologic manifestations of the disease. However, many other entities can present with clinical and/or histologic features of celiac disease. In this review article, we highlight key clinical and histologic mimickers of celiac disease. The evaluation of a patient with serologically negative enteropathy necessitates a carefully elicited history and detailed review by a pathologist. Medications can mimic celiac disease and should be considered in all patients with a serologically negative enteropathy. Many mimickers of celiac disease have clues to the underlying diagnosis, and many have a targeted therapy. It is necessary to provide patients with a correct diagnosis rather than subject them to a lifetime of an unnecessary gluten-free diet.

  20. Radiologic analysis of femoral acetabular impingement: from radiography to MRI

    Energy Technology Data Exchange (ETDEWEB)

    Dwek, Jerry R. [University of California at San Diego, Department of Radiology, Rady Children' s Hospital and Health Center, San Diego, CA (United States); San Diego Imaging, San Diego, CA (United States); Monazzam, Shafagh [Rady Children' s Hospital and Health Center, Department of Orthopedics, San Diego, CA (United States); Chung, Christine B. [University of California at San Diego, Department of Radiology, San Diego, CA (United States)

    2013-03-15

    Femoral acetabular impingement is a set of morphologic abnormalities that are considered to be a major cause of degenerative disease in the hip joint. Early changes are already present in adolescence when it is the pediatric radiologist who must assess current damage with the aim of averting progression to more severe and debilitating osteoarthritis. A multimodality approach is used for diagnosis, that includes conventional radiography and CT to assess the osseous structures. MR arthrography is the primary advanced imaging modality for assessment of morphologic changes as well as injuries of the labrum and articular cartilage. Details of radiologic imaging are offered to guide the radiologist and provide an avenue for the accurate description of the osseous and articular alterations and injury. (orig.)

  1. The etiology of primary femoroacetabular impingement: genetics or acquired deformity?

    Science.gov (United States)

    Packer, Jonathan D; Safran, Marc R

    2015-10-01

    The etiology of primary femoroacetabular impingement (FAI) remains controversial. Both genetic and acquired causes have been postulated and studied. While recent studies suggest that genetic factors may have a role in the development of FAI, there is no conclusive evidence that FAI is transmitted genetically. Currently, the most popular theory for the development of cam-type deformities is that a repetitive injury to the proximal femoral physis occurs during a critical period of development. There is a correlation between a high volume of impact activities during adolescence and the development of cam-type deformities. Multiple studies have found a high prevalence of FAI in elite football, ice hockey, basketball and soccer players. In this article, we review the current literature relating to the etiology of primary FAI.

  2. The etiology of primary femoroacetabular impingement: genetics or acquired deformity?

    Science.gov (United States)

    Packer, Jonathan D.; Safran, Marc R.

    2015-01-01

    The etiology of primary femoroacetabular impingement (FAI) remains controversial. Both genetic and acquired causes have been postulated and studied. While recent studies suggest that genetic factors may have a role in the development of FAI, there is no conclusive evidence that FAI is transmitted genetically. Currently, the most popular theory for the development of cam-type deformities is that a repetitive injury to the proximal femoral physis occurs during a critical period of development. There is a correlation between a high volume of impact activities during adolescence and the development of cam-type deformities. Multiple studies have found a high prevalence of FAI in elite football, ice hockey, basketball and soccer players. In this article, we review the current literature relating to the etiology of primary FAI. PMID:27011846

  3. Current concepts in the diagnosis and treatment of shoulder impingement

    Directory of Open Access Journals (Sweden)

    Bijayendra Singh

    2017-01-01

    Full Text Available Subacromial impingement syndrome (SIS is a very common cause of shoulder pain in the young adults. It can cause debilitating pain, dysfunction, and affects the activities of daily living. It represents a spectrum of pathology ranging from bursitis to rotator cuff tendinopathy which can ultimately lead to degenerative tear of the rotator cuff. Various theories and concepts have been described and it is still a matter of debate. However, most published studies suggest that both extrinsic and intrinsic factors have a role in the development of SIS. The management is controversial as both nonoperative and operative treatments have shown to provide good results. This article aims to provide a comprehensive current concepts review of the pathogenesis, etiologies, clinical diagnosis, appropriate use of investigations, and discussion on the management of SIS.

  4. Heat transfer and phase change in an impinging droplet

    Science.gov (United States)

    Rangchian, Aysan; Shirazi, Nikki L.; Kavehpour, H. Pirouz

    2016-11-01

    Non isothermal droplet impact on solid surfaces has several industrial applications such as spray cooling and 3D printing. Impinging of a droplet on a surface involves an initial phase of spreading followed by a subsequent return to the equilibrium shape. Thermal energy exchanged within the droplet fluid as well as between liquid/solid during the impact has been studied using an ultra high speed infrared camera. Variable parameters in the experiment include droplet temperature and kinetic energy of the droplet during the impact. The evolution of droplet shape viewed by IR camera is similar to what previously observed by high speed photography. The thermal map of droplet over time in these experiments agrees with previously reported numerical simulation. In addition, spacial and temporal temperature variations of liquid droplets on a surface as they solidify are presented. IR camera provides an accurate temperature diagram as the phase change occurs, which is essential for understanding the physics of 3D printing.

  5. Muscle impingement: MR imaging of a painful complication of osteochondromas

    Energy Technology Data Exchange (ETDEWEB)

    Uri, D.S. [Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104 (United States); Dalinka, M.K. [Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104 (United States); Kneeland, J.B. [Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104 (United States)

    1996-10-01

    The purpose of this study was to describe the magnetic resonance (MR) appearance of a newly recognized complication of osteochondromas. Two patients presented with pain and swelling over known osteochondromas. Plain radiographic studies were unrevealing. MR examinations were obtained to characterize the exostoses further and evaluate areas of palpable fullness. Increased signal was present in the muscles on T2-weighted images, which correlated with physical findings and was believed to represent muscle injury due to the osteochondroma. Pain and fullness may result from a number of osteochondroma-related complications, the most worrisome of which is malignant degeneration. Muscular impingement and injury should be considered in the differential diagnosis of pain and swelling in the region of an exostosis. MR imaging allows distinction of this entity, which may be radiographically occult and confused clinically with fracture, bursitis, or malignant degeneration. (orig.). With 2 figs.

  6. The Use of Physiotherapy among Patients with Subacromial Impingement Syndrome

    DEFF Research Database (Denmark)

    Christiansen, David Høyrup; Frost, Poul; Frich, Lars Henrik

    2016-01-01

    BACKGROUND: Physiotherapy with exercises is generally recommended in the treatment of patients with subacromial impingement syndrome (SIS). OBJECTIVE: We aimed to investigate the use of physiotherapy in patients with SIS in Danish hospital settings as part of initial non-surgical treatment...... and after SIS-related surgery and to evaluate to which extent sex, socio-demographic and clinical factors predict the use of physiotherapy. METHODS: Using national health registers, we identified 57,311 patients who had a first hospital contact with a diagnosis of ICD-10, groups M75.1-75.9, 1 July 2007...... to 30 June 2011. Records of physiotherapy were extracted within 52 weeks after first contact (or until surgery), and for surgically treated patients within 26 weeks after surgery. Predictors of the use of physiotherapy after first contact and after surgery were analysed as time-to-event. RESULTS: Within...

  7. Arbitrary Lagrangian-Eulerian method for computation of impinging droplet with soluble surfactants and dynamic contact angle

    CERN Document Server

    Ganesan, Sashikumaar

    2014-01-01

    An arbitrary Lagrangian--Eulerian (ALE) finite element scheme for computations of soluble surfactant droplet impingement on a horizontal surface is presented. The numerical scheme solves the time-dependent Navier--Stokes equations for the fluid flow, scalar convection-diffusion equation for the surfactant transport in the bulk phase, and simultaneously, surface evolution equations for the surfactants on the free surface and on the liquid-solid interface. The effects of surfactants on the flow dynamics are included into the model through the surfactant-dependent surface tension and dynamic contact angle. In particular, the dynamic contact angle of the droplet is defined as a function of surfactants using the nonlinear equation of state for surface tension. Further, the surface forces are included in the model using the Boussinesq-Scriven law that allows to incorporate the Marangoni effects without evaluating the gradients of surfactant concentration on the free surface. In addition to a mesh convergence study ...

  8. Effect of nozzle-to-plate spacing on the development of a plane jet impinging on a heated plate

    Science.gov (United States)

    Rim, Ben Kalifa; Saïd, Nejla Mahjoub; Bournot, Hervé; Le Palec, Georges

    2016-09-01

    An experimental investigation was carried out to study the behavior of a turbulent air jet impinging on a heated plate. The study of the flow field was performed using a particle image velocimetry. A three-dimensional numerical model with Reynolds stress model has been conducted to examine the global flow. Numerical results agree well with experimental data. The main properties of the fluid occurring between the nozzle and the flat plate are presented. In addition, the effect of the distance between the nozzle exit and the plate (h/e = 14 and 28) were investigated and detailed analysis of the dynamic, turbulent distribution and temperature fields were performed. The wall shear stress and the pressure fields near the heated plate are then explored. Results showed that the mean velocity and the heat transfer characteristics of small nozzle-to-plate spacing are significantly different from those of large nozzle-to-plate spacing.

  9. Pseudocyclops: two cases of ACL graft partial tears mimicking cyclops lesions on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Simpfendorfer, Claus; Subhas, Naveen; Winalski, Carl S.; Ilaslan, Hakan [Cleveland Clinic, Department of Radiology, Cleveland, OH (United States); Miniaci, Anthony [Cleveland Clinic, Department of Orthopedics, Cleveland, OH (United States)

    2015-08-15

    Arthroscopic reconstruction of the anterior cruciate ligament (ACL) using autografts or allografts is a common surgical procedure, particularly in young athletes. Although the procedure has excellent success rates, complications such as mechanical impingement, graft rupture, and arthrofibrosis can occur, often necessitating additional surgery. Magnetic resonance (MR) imaging has become a valuable tool in evaluating complications after ACL reconstruction. We report two cases of ACL reconstruction complicated by arthroscopically proven partial graft tears. In both cases the torn anterior graft fibers were flipped into the intercondylar notch, mimicking anterior arthrofibrosis, i.e., a ''cyclops lesion,'' on MR imaging. Careful review of the direction of graft fibers on MR imaging in the ''pseudocyclops'' lesions can help differentiate these partial tears from the fibrosis of a true cyclops. The ''pseudocyclops'' lesion is a previously undescribed MR imaging sign of partial ACL graft tear. Larger studies are required to determine the sensitivity and specificity of the sign, as well as the clinical importance of these partial graft tears. (orig.)

  10. Molecular Characterization of Articular Cartilage from Young Adults with Femoroacetabular Impingement

    Science.gov (United States)

    Hashimoto, Shingo; Rai, Muhammad Farooq; Gill, Corey S.; Zhang, Zhiqi; Sandell, Linda J.; Clohisy, John C.

    2013-01-01

    Background: Femoroacetabular impingement is a frequent cause of hip pain and may lead to secondary osteoarthritis, yet little is known about the molecular events linking mechanical hip impingement and articular cartilage degeneration. The first goal of this study was to quantify the expression of inflammatory cytokine and chemokine, matrix-degrading, and extracellular matrix genes in articular cartilage harvested from control hips and hips with femoroacetabular impingement and end-stage osteoarthritis. The second goal was to analyze the relative expression of these genes in articular cartilage harvested at various stages of osteoarthritis. Methods: Cartilage samples were obtained from thirty-two hips undergoing hip preservation surgery for femoroacetabular impingement or hip arthroplasty. Three control cartilage samples were also analyzed. Specimens were graded intraoperatively with regard to the severity of cartilage damage, the radiographic osteoarthritis grade was recorded, and quantitative RT-PCR (real-time polymerase chain reaction) was performed to determine relative gene expression. Results: Except for interleukin-1β (IL-1β) and CXCL2, the mRNA (messenger RNA) expression of all other chemokine (IL-8, CXCL1, CXCL3, CXCL6, CCL3, and CCL3L1), matrix-degrading (matrix metalloproteinase [MMP]-13 and ADAMTS-4), and structural matrix (COL2A1 [collagen, type II, alpha] and ACAN [aggregan]) genes was higher overall in cartilage from hips with femoroacetabular impingement compared with hips with osteoarthritis and normal controls. The differences reached significance (p ≤ 0.05) for seven of these ten quantified genes, with CXCL3, CXCL6, and COL2A1 being elevated in the femoroacetabular impingement group compared with only the control group and IL-8, CCL3L1, ADAMTS-4, and ACAN being elevated compared with both the osteoarthritis and control groups. When samples were grouped according to the stage of the degenerative cascade, mRNA expression was relatively higher in

  11. Biomass and number of fish impinged at a nuclear power plant by the Baltic Sea.

    Science.gov (United States)

    Bryhn, Andreas C; Bergenius, Mikaela A J; Dimberg, Peter H; Adill, Anders

    2013-12-01

    The main aim of this study was to investigate the number and biomass of impinged fish at Forsmark Nuclear Power Plant in Sweden, located on the coast of the Baltic Sea. Of particular interest was the number of impinged individuals of the critically endangered European eel (Anguilla anguilla) which is regularly caught in the cooling system. Another aim was to determine the comparability of the results from Forsmark and results from impingement studies in other types of waters. Cross-systems studies make it possible to (1) estimate fish loss at plants where fish is not counted, and (2) to predict changes in fish loss from changes in electricity production or cooling water use. In 2010, 31,300,000 fish with a total biomass of 62,600 kg were impinged at Forsmark. In 2011, 27,300,000 fish weighing 38,500 kg were impinged. The maximum peak in total fish number and biomass occurred in spring. The most critical period for herring was in late summer and early autumn. Regarding eel, the largest impingement losses were recorded in November. The number of fish agreed with earlier established quantities of impinged fish in both freshwater and marine ecosystems. The study also estimated that 1,300 critically endangered eels could survive at Forsmark each year if a fish return system would be constructed to allow the passage of fish from the plant back to the Baltic Sea.

  12. A closed-loop electronics cooling by implementing single phase impinging jet and mini channels heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Bintoro, Jemmy S. [University of Maine, Laboratory for Surface Science and Technology (LASST), ESRB-Barrows, Orono, ME, 04469-5708 (United States); Akbarzadeh, Aliakbar [RMIT University, Bundoora East Campus, P.O. Box 71, Bundoora, Vic. 3083 (Australia); Mochizuki, Masataka [1-5-1, Kiba, Koto-ku, Tokyo 135-8512 (Japan)

    2005-12-01

    This paper reports our works in the design and testing of a closed-loop electronics cooling system that adopts bi-technologies: single phase impinging jet and mini channels heat exchanger. The system has the cooling capacity of 200W over a single chip with a hydraulic diameter of 12mm. The equivalent heat flux is 177W/cm{sup 2}. The cooling system maintains the chip's surface temperature below 95{sup o}C maximum when the ambient temperature is 30{sup o}C. De-ionized water is the working fluid of the system. For the impinging jet, two different nozzles are designed and tested. The hydraulic diameters (d{sub N}) are 0.5mm and 0.8mm. The corresponding volume flow rates are 280mL/min and 348mL/min. Mini channels heat exchanger has 6 (six) copper tubes with the inner diameter of 1.27mm and the total length of about 1m. The cooling system has a mini diaphragm pump and a DC electric fan with the maximum power consumptions of 8.4W and 0.96W respectively. The coefficient of performance of the system is 21.4. (author)

  13. Inherited cardiomyopathies mimicking arrhythmogenic right ventricular cardiomyopathy.

    Science.gov (United States)

    Roberts, Jason D; Veinot, John P; Rutberg, Julie; Gollob, Michael H

    2010-01-01

    Arrhythmogenic right ventricular cardiomyopathy (ARVC) represents an inherited cardiomyopathy that manifests clinically with malignant ventricular arrhythmias, sudden cardiac death, and less commonly heart failure. The condition is characterized by replacement of the myocardium, primarily of the right ventricle, with fibrofatty tissue. Extensive fibrofatty replacement of the myocardium has been previously thought to be pathognomonic of ARVC; however, this report details two other forms of inherited cardiomyopathy, namely hypertrophic cardiomyopathy (HCM) and the PRKAG2 cardiac syndrome, that were found to have significant fibrofatty myocardial replacement at pathologic examination. This report represents the first documentation of inherited cardiomyopathies mimicking ARVC and highlights the concept that other cardiac conditions can be associated with fibrofatty replacement of the myocardium. Copyright 2010 Elsevier Inc. All rights reserved.

  14. Tentorium schwannoma mimicking meningioma: an unusual location.

    Science.gov (United States)

    Calişaneller, Tarkan; Ozen, Ozlem; Altinörs, Nur; Caner, Hakan

    2008-07-01

    A 60-year-old female was admitted to our clinic complaining of a long-lasting headache. Cranial magnetic resonance imagining examination of the patient revealed a 22x24 mm extra-axial, well-demarcated, mass lesion based on the left tentorium. The patient underwent a craniotomy and the tumor was totally excised with the adjacent tentorium. The histopathological examination of the tumor complied with the diagnosis of schwannoma. The rest of the clinical course was uneventful and the patient was released from the hospital without any neurological deficit. Intracranial schwannomas can rarely originate from atypical dural locations and radiological techniques are not always helpful in distinguishing tentorial schwannoma from tentorial meningioma. We presented a patient with a tentorium schwannoma mimicking meningioma and discussed the current literature.

  15. Orbital Lymphoma Mimicking Lacrimal Gland Pleomorphic Adenoma

    Directory of Open Access Journals (Sweden)

    Diego Strianese

    2013-09-01

    Full Text Available Purpose: To describe the case of a patient affected by orbital lymphoma mimicking pleomorphic adenoma of the lacrimal gland. Methods: This was a retrospective case report. Results: We present the case of a patient with 15-year history of slowly progressive left proptosis and inferomedial bulbar dislocation who had the presumptive diagnosis of lacrimal gland pleomorphic adenoma based on clinical and radiological features. The patient underwent lateral orbitotomy and lacrimal gland excision. Postoperative histological features were consistent with low-grade B-cell non-Hodgkin lymphoma. Conclusion: The accepted clinico-radiological criteria used for the diagnosis of lacrimal gland fossa lesions might have a certain false-positive rate, even in recent years. The initial surgical approach with the appropriate choice between fine-needle aspiration biopsies, intraoperative biopsies and lacrimal gland excisions might be a challenge.

  16. Prolonged acute hepatitis A mimicking autoimmune hepatitis

    Institute of Scientific and Technical Information of China (English)

    Rintaro Mikata; Osamu Yokosuka; Fumio Imazeki; Kenichi Fukai; Tatsuo Kanda; Hiromitsu Saisho

    2005-01-01

    AIM: We report a case with a prolonged course of hepatitisA, with alanine aminotransferase (ALT) higher than 500 IU/Lfor more than 2 mo.METHODS: A middle-aged woman had an elevated IgG level of more than 2 000 mg/dL, positive arti-nudear antibodies (ANA) and anti-smooth muscle antibodies (ASMA), but no evidence of persistent hepatitis A virus (HAV) infection. Liver biopsy findings were compatible with prolonged acute hepatitis, although acute onset of autoimmune hepatitis could not be ruled out.RESULTS: It was assumed that she developed a course of hepatitis similar to autoimmune hepatitis triggered by HAV infection. Ursodeoxycholic acid (UDCA) treatment was initiated and a favorable outcome was obtained. CONCLUSION: We describe a case of a middle-aged woman who showed a prolonged course of acute hepatitis A mimicking autoimmune hepatitis. Treatment with UDCAproved to be effective.

  17. Case report. Pityriasis versicolor mimicking Pityriasis rotunda.

    Science.gov (United States)

    Aste, Nicola; Pau, Monica; Aste, Natalia; Biggio, P

    2002-04-01

    Pityriasis versicolor is a common dermatomycosis, occurring throughout the world, characterized by irregular, slightly scaly patches, varying in color from red/light brown to white. Pityriasis rotunda, on the other hand, is an uncommon disease, reported in specific ethnic groups, and characterized by perfectly round or oval patches of varying color, with a scaly surface. The histologic pattern is that of ichthyosis vulgaris. We report here the case of a male patient, aged 31, from Sardinia (Italy), affected by Pityriasis versicolor mimicking Pityriasis rotunda. Mycological examination allowed us to formulate the correct diagnosis, and ensuing treatment with antifungal drugs was entirely successful. The authors, while pointing out the rarity of this case, stress the possibility that Pityriasis versicolor mimics Pityriasis rotunda and vice-versa, especially in those countries in which the two diseases are endemic. More widespread recourse to microscopic examination can help avoid the risk of mistaken diagnosis and consequent incorrect treatment.

  18. A subtle mimicker in emergency department

    Science.gov (United States)

    Angelis, Maria Vittoria De; Giacomo, Roberta Di; Muzio, Antonio Di; Onofrj, Marco; Bonanni, Laura

    2016-01-01

    Abstract Background: Movement disorder emergencies include any movement disorder which develops over hours to days, in which failure to appropriately diagnose and manage can result in patient morbidity or mortality. Movement disorder emergencies include acute dystonia: sustained or intermittent muscle contractions causing abnormal, often repetitive, movements. Acute dystonia is a serious challenge for emergency room doctors and neurologists, because of the high probability of misdiagnosis, due to the presence of several mimickers including partial seizures, meningitis, localized tetanus, serum electrolyte level abnormalities, strychnine poisoning, angioedema, malingering, catatonia, and conversion. Methods: We describe 2 examples, accompanied by videos, of acute drug-induced oro-mandibular dystonia, both subsequent to occasional haloperidol intake. Results: Management and treatment of this movement disorder are often difficult: neuroleptics withdrawal, treatment with benzodiazepines, and anticholinergics are recommended. Conclusion: Alternative treatment options are also discussed. PMID:27741141

  19. Contiguous spinal metastasis mimicking infectious spondylodiscitis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chul Min; Lee, Seung Hun [Dept. of Radiology, Hanyang University Hospital, Seoul (Korea, Republic of); Bae, Ji Yoon [Dept. of Pathology, National Police Hospital, Seoul (Korea, Republic of)

    2015-12-15

    Differential diagnosis between spinal metastasis and infectious spondylodiscitis is one of the occasional challenges in daily clinical practice. We encountered an unusual case of spinal metastasis in a 75-year-old female breast cancer patient that mimicked infectious spondylodiscitis. Magnetic resonance imaging (MRI) showed diffuse bone marrow infiltrations with paraspinal soft tissue infiltrative changes in 5 contiguous cervical vertebrae without significant compression fracture or cortical destruction. These MRI findings made it difficult to differentiate between spinal metastasis and infectious spondylodiscitis. Infectious spondylodiscitis such as tuberculous spondylodiscitis was regarded as the more appropriate diagnosis due to the continuous involvement of > 5 cervical vertebrae. The patient's clinical presentation also supported the presumptive diagnosis of infectious spondylodiscitis rather than spinal metastasis. Intravenous antibiotics were administered, but clinical symptoms worsened despite treatment. After pathologic confirmation by computed tomography-guided biopsy, we were able to confirm a final diagnosis of spinal metastasis.

  20. Lumbar Epidural Varix Mimicking Perineural Cyst

    Science.gov (United States)

    Pusat, Serhat; Kural, Cahit; Aslanoglu, Atilla; Kurt, Bulent

    2013-01-01

    Lumbar epidural varices are rare and usually mimick lumbar disc herniations. Back pain and radiculopathy are the main symptoms of lumbar epidural varices. Perineural cysts are radiologically different lesions and should not be confused with epidural varix. A 36-year-old male patient presented to us with right leg pain. The magnetic resonance imaging revealed a cystic lesion at S1 level that was compressing the right root, and was interpreted as a perineural cyst. The patient underwent surgery via right L5 and S1 hemilaminectomy, and the lesion was coagulated and removed. The histopathological diagnosis was epidural varix. The patient was clinically improved and the follow-up magnetic resonance imaging showed the absence of the lesion. Lumbar epidural varix should be kept in mind in the differential diagnosis of the cystic lesions which compress the spinal roots. PMID:23741553

  1. How "healthy" is circuit resistance training following paraplegia? Kinematic analysis associated with shoulder mechanical impingement risk

    Directory of Open Access Journals (Sweden)

    Deborah A. Nawoczenski, PT, PhD

    2013-08-01

    Full Text Available The purpose of the study was to determine whether wheelchair-based circuit resistance training (CRT exercises place the shoulder at risk for mechanical impingement. Using a novel approach, we created a mechanical impingement risk score for each exercise by combining scapular and glenohumeral kinematic and exposure data. In a case series design, 18 individuals (25–76 yr old with paraplegia and without substantial shoulder pain participated. The mean mechanical impingement risk scores at 45–60 degrees humerothoracic elevation were rank-ordered from lowest to highest risk as per subacromial mechanical impingement risk: overhead press (0.6 +/– 0.5 points, lat pulldown (1.2 +/– 0.5 points, chest press (2.4 +/– 2.8 points, row (2.7 +/– 1.6 points, and rickshaw (3.4 +/– 2.3 points. The mean mechanical impingement risk scores at 105–120 degrees humerothoracic elevation were rank-ordered from lowest to highest risk as per internal mechanical impingement risk: lat pulldown (1.2 +/– 0.5 points and overhead press (1.3 +/– 0.5 points. In conclusion, mechanical impingement risk scores provided a mechanism to capture risk associated with CRT. The rickshaw had the highest subacromial mechanical risk, whereas the overhead press and lat pulldown had the highest internal mechanical impingement risk. The rickshaw was highlighted as the most concerning exercise because it had the greatest combination of magnitude and exposure corresponding with increased subacromial mechanical impingement risk.

  2. Peroneal spastic flatfoot in adolescents with accessory talar facet impingement: a preliminary report.

    Science.gov (United States)

    Niki, Hisateru; Aoki, Haruhito; Hirano, Takaaki; Akiyama, Yui; Fujiya, Hiroto

    2015-07-01

    This study analyzed imaging, arthroscopic findings, and treatment responses for peroneal spastic flatfoot (PSFF) caused by talocalcaneal impingement at the accessory anterolateral talar facet (AALTF) (accessory talar facet impingement) in 13 adolescents without histories of trauma and tarsal coalition. The AALTF was determined with computed tomography and MRI. Focal abutting bone marrow edema (FABME) on MRI around the AALTF was confirmed. In seven patients who underwent AALTF resection, subtalar arthroscopy was performed. All experienced alleviation PSFF after treatment; reduction in FABME was observed. AALTF resection alone is beneficial for PSFF caused by accessory talar facet impingement when peroneal spasms are restored by an injection of local anesthesia.

  3. Can Bracing Affect Altered Gait Patterns in Femoroacetabular Impingement

    Science.gov (United States)

    Safran, Marc R.; Rylander, Jonathan; Shu, Beatrice; Andriacchi, Thomas P.

    2013-01-01

    Objectives: Altered gait patterns have been identified in patients with Femoroacetabular impingement (FAI), a 2nd order reversal in mid stance, that has been shown to be corrected with arthroscopic FAI surgery. Currently, most feel there is no adequate conservative treatment for this malady. The goal of this study is to determine if the gait abnormalities seen with femoroacetabular impingement (FAI) can be modified with bracing. Methods: Eight individuals (4 Male, 34.5 ± 12.8 y.o., 24.0±2.3 BMI) who were diagnosed with FAI after reporting to clinic with groin pain were enrolled in this study. The study was approved by the University Internal Review Board before participants were enrolled. History, clinical exam, and imaging including an AP pelvis and cross table lateral radiograph of the affected hip and MR-arthrogram of the affected hip were utilized to make the diagnosis. Participants who enrolled had primarily unilateral hip symptoms, had positive impingement and labral stress tests on the affected side and were free of other lower extremity, back, and spine disorders. Three dimensional lower limb kinematics were collected using a camera and forceplate system with the subjects wearing reflective markers on anatomical landmarks. Participants were tested prior to surgery. Hip kinematics were collected for the symptomatic limb while the patients walked at a self selected normal walking speed, slowly jogged, and ascended a two stair setup. Three trials for each activity were completed with and without wearing a brace that was designed to externally rotate the femur in the treatment of patellofemoral disorders for a total of 6 trials per activity. Peak hip flexion, extension, abduction, adduction, internal rotation, and external rotation were calculated over the stance phase for each trial. Averages were calculated over the 3 trials for each activity both with and without the brace. Intra-subject differences were compared between the braced and unbraced trials

  4. Subacromial Tenoxicam Injection in the Treatment of Impingement Syndrome

    Science.gov (United States)

    Çift, Hakan; Özkan, Feyza Ünlü; Şeker, Ali; İşyar, Mehmet; Ceyhan, Erman; Mahiroğulları, Mahir

    2014-01-01

    Objectives: As subacromial bursa injection is widely used for pain relief and functional improvements in patients with periarticular shoulder disorder, we aimed to present our results of subacromial tenoxicam injection in the treatment of impingement syndrome. Methods: Patients presented to the Department of Orthopaedics and Traumatology, Istanbul Medipol University with the primary complaints of shoulder pain from January 2012 to June 2013 were selected. Those who met the following inclusion criteria were finally considered: 1) who had a clinical sign of a painful arc and positive in Hawkins test and/or Neer impingement sign; 2) who had a precise rotator cuff injury including partial cuff tears, or subacromial bursitis detected during ultrasonography or MRI. The exclusion criteria were as follows: 1) who underwent shoulder surgery; 2) who had full thickness rotator cuff rupture; 3) who had hemiplegic shoulder pain; and 4) who displayed any suspected fracture on X-ray or had a recent shoulder trauma; 5) who showed limited active ROM and stiffness due to adhesive capsulitis. Thirty one shoulders out of thirty patients were treated with subacromial tenoxicam injection. Ten of them were left shoulders. Fifteen of the patients were women.. Patients had a mean age of 51.6 (30-73). Patients were evaluated 4 times. Before the first injection, 1 week after the first injection, 2 weeks after the second injection and 3 weeks after the third injection. In every injection 20 mg tenoxicam was performed. Results: In order to relieve the pain; two patients were given only one injection, thirteen patients were given two injections and “3 injections protocol” were done to fifteen patients. The mean pre- and posttreatment VAS scores were 7.9 (between, 7-9) and 2.7 (between, 2-4) points respectively. The average pre and posttreatment DASH scores were 59.41 (between, 45-80) and 14 (between, 8.3-25.8) points respectively. The mean pre and posttreatment range of motion were 106

  5. Modified Regression Rate Formula of PMMA Combustion by a Single Plane Impinging Jet

    Directory of Open Access Journals (Sweden)

    Tsuneyoshi Matsuoka

    2017-01-01

    Full Text Available A modified regression rate formula for the uppermost stage of CAMUI-type hybrid rocket motor is proposed in this study. Assuming a quasi-steady, one-dimensional, an energy balance against a control volume near the fuel surface is considered. Accordingly, the regression rate formula which can calculate the local regression rate by the quenching distance between the flame and the regression surface is derived. An experimental setup which simulates the combustion phenomenon involved in the uppermost stage of a CAMUI-type hybrid rocket motor was constructed and the burning tests with various flow velocities and impinging distances were performed. A PMMA slab of 20 mm height, 60 mm width, and 20 mm thickness was chosen as a sample specimen and pure oxygen and O2/N2 mixture (50/50 vol.% were employed as the oxidizers. The time-averaged regression rate along the fuel surface was measured by a laser displacement sensor. The quenching distance during the combustion event was also identified from the observation. The comparison between the purely experimental and calculated values showed good agreement, although a large systematic error was expected due to the difficulty in accurately identifying the quenching distance.

  6. Numerical modeling of a turbulent semi-confined slot jet impinging on a concave surface

    Directory of Open Access Journals (Sweden)

    Ahmadi Hadi

    2015-01-01

    Full Text Available This article presents results from a numerical study of a turbulent slot jet impinging on a concave surface. Five different low Reynolds number k-ε models were evaluated to predict the heat transfer under a two dimensional steady turbulent jet. The effects of flow and geometrical parameters (e.g. jet Reynolds number and jet-to-target separation distance have been investigated. The Yap correction is applied for reducing the over-prediction of Nusselt number in the near wall region. It is shown that among the models tested in this study, the LS-Yap model is capable of predicting local Nusselt number in good agreement with the experimental data in both stagnation and wall jet region. Moreover, after implementation of Yap correction, no significant effect of the nozzle-to-surface distance, h/B, on the predicted stagnation Nusselt number has been found. Finally it is demonstrated that the higher values of turbulent Prandtl number reduces the heat diffusion along the wall and consequently the predicted local Nusselt number is reduced especially in the wall jet region.

  7. [Effectiveness of physiotherapy on painful shoulder impingement syndrome].

    Science.gov (United States)

    Gomora-García, Mónica; Rojano-Mejía, David; Solis-Hernández, José Luis; Escamilla-Chávez, Carolina

    2016-01-01

    Painful shoulder impingement syndrome is one of the first reasons for care in rehabilitation centres. As the evidence regarding the effectiveness of physical measures as adjuvant treatment is limited, the aim of this study was to determine the effectiveness of physiotherapy on shoulder pain. A retrospective and analytical study was conducted using the medical records of patients with shoulder pain who attended in a rehabilitation centre from October 2010 to September 2011. The demographic and clinical data were collected, and the clinical improvement was determined as: complete, incomplete, or no improvement. Chi squared was used to determine whether there were differences between the different modalities of physiotherapy, as well as the level of improvement. The study included a total of 181 patients, with a mean age of 54.3 years, and a mean of 4.6 months of onset of pain. The physiotherapy treatments included: warm compresses plus interferential current (60.2%), and warm compresses plus ultrasound (17.1%). Just over half (53.6%) obtained a moderate recovery, 36.4% slight improvement, and 9.9% no improvement. No significant differences were found between the different forms of therapy. The supervised rehabilitation program consists of 9 sessions of physiotherapy. A functional improvement of 90% was obtained, without finding any statistical differences between the therapies used. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

  8. Low extreme-ultraviolet luminosities impinging on protoplanetary disks

    Energy Technology Data Exchange (ETDEWEB)

    Pascucci, I.; Hendler, N. P. [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Ricci, L. [Department of Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Gorti, U.; Hollenbach, D. [SETI Institute, 189 Bernardo Ave., Mountain View, CA 94043 (United States); Brooks, K. J.; Contreras, Y., E-mail: pascucci@lpl.arizona.edu [Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia)

    2014-11-01

    The amount of high-energy stellar radiation reaching the surface of protoplanetary disks is essential to determine their chemistry and physical evolution. Here, we use millimetric and centimetric radio data to constrain the extreme-ultraviolet (EUV) luminosity impinging on 14 disks around young (∼2-10 Myr) sun-like stars. For each object we identify the long-wavelength emission in excess to the dust thermal emission, attribute that to free-free disk emission, and thereby compute an upper limit to the EUV reaching the disk. We find upper limits lower than 10{sup 42} photons s{sup –1} for all sources without jets and lower than 5 × 10{sup 40} photons s{sup –1} for the three older sources in our sample. These latter values are low for EUV-driven photoevaporation alone to clear out protoplanetary material in the timescale inferred by observations. In addition, our EUV upper limits are too low to reproduce the [Ne II] 12.81 μm luminosities from three disks with slow [Ne II]-detected winds. This indicates that the [Ne II] line in these sources primarily traces a mostly neutral wind where Ne is ionized by 1 keV X-ray photons, implying higher photoevaporative mass loss rates than those predicted by EUV-driven models alone. In summary, our results suggest that high-energy stellar photons other than EUV may dominate the dispersal of protoplanetary disks around sun-like stars.

  9. CFD Approaches for Modelling Bubble Entrainment by an Impinging Jet

    Directory of Open Access Journals (Sweden)

    Martin Schmidtke

    2009-01-01

    Full Text Available This contribution presents different approaches for the modeling of gas entrainment under water by a plunging jet. Since the generation of bubbles happens on a scale which is smaller than the bubbles, this process cannot be resolved in meso-scale simulations, which include the full length of the jet and its environment. This is why the gas entrainment has to be modeled in meso-scale simulations. In the frame of a Euler-Euler simulation, the local morphology of the phases has to be considered in the drag model. For example, the gas is a continuous phase above the water level but bubbly below the water level. Various drag models are tested and their influence on the gas void fraction below the water level is discussed. The algebraic interface area density (AIAD model applies a drag coefficient for bubbles and a different drag coefficient for the free surface. If the AIAD model is used for the simulation of impinging jets, the gas entrainment depends on the free parameters included in this model. The calculated gas entrainment can be adapted via these parameters. Therefore, an advanced AIAD approach could be used in future for the implementation of models (e.g., correlations for the gas entrainment.

  10. Absorption of impinging water droplet in porous stones.

    Science.gov (United States)

    Lee, J B; Radu, A I; Vontobel, P; Derome, D; Carmeliet, J

    2016-06-01

    This paper presents an experimental investigation and numerical analysis of the absorption of water droplets impacting porous stones. The absorption process of an impinging droplet is here fully characterized from spreading to evaporation in terms of absorbed mass during droplet depletion and moisture content distribution in a time-resolved manner for three different natural stones. High-speed imaging and neutron radiography are used to quantify moisture absorption in porous stones of varying moisture properties from deposition until depletion. During impact and spreading, the droplet exhibits a dynamic non-wetting behavior. At maximum spreading, the droplet undergoes pinning, resulting into the contact radius remaining constant until droplet depletion. Absorption undergoes two phases: initially, absorption is hindered due a contact resistance attributed to entrapped air; afterwards, a more perfect capillary contact occurs and absorption goes on until depletion, concurrently with evaporation and further redistribution. A finite-element numerical model for isothermal unsaturated moisture transport in porous media captures the phases of mass absorption in good agreement with the experimental data. Droplet spreading and absorption are highly determined by the impact velocity of the droplet, while moisture content redistribution after depletion is much less dependent on impact conditions.

  11. Subacromial impingement syndrome: the role of posture and muscle imbalance.

    Science.gov (United States)

    Lewis, Jeremy S; Green, Ann; Wright, Christine

    2005-01-01

    Changes in upper body posture, colloquially termed forward head posture (FHP), are considered to be an etiologic factor in the pathogenesis of subacromial impingement syndrome (SIS). The literature suggests that postural deviations associated with FHP follow distinct patterns involving an increase in the thoracic kyphosis angle and a downwardly rotated, anteriorly tilted, and protracted scapula, which in turn leads to increased compression in the subacromial space. These postural changes are thought to occur concurrently with an imbalance of the musculature, and conservative rehabilitation commonly involves addressing both posture and muscle imbalance. There is a paucity of evidence supporting the hypothesis that posture and muscle imbalance are involved in the etiology of SIS. The purpose of this study was to investigate whether FHP was associated with an increased thoracic kyphosis, an altered position of the scapula; and a reduction in glenohumeral elevation range. Selected sagittal and frontal plane postural measurements were made in 60 asymptomatic subjects and 60 subjects with SIS. The findings suggested that upper body posture does not follow the set patterns described in the literature, and further research is required to determine whether upper body and scapular posture and muscle imbalance are involved in the pathogenesis of SIS.

  12. Quantifying shoulder rotation weakness in patients with shoulder impingement.

    Science.gov (United States)

    Tyler, Timothy F; Nahow, Rachael C; Nicholas, Stephen J; McHugh, Malachy P

    2005-01-01

    The purpose of this study was to determine whether strength deficits could be detected in individuals with and without shoulder impingement, all of whom had normal shoulder strength bilaterally according to grading of manual muscle testing. Strength of the internal rotators and external rotators was tested isokinetically at 60 degrees /s and 180 degrees /s, as well as manually with a handheld dynamometer (HHD) in 17 patients and 22 control subjects. Testing was performed with the shoulder positioned in the scapular plane and in 90 degrees of shoulder abduction with 90 degrees of elbow flexion (90-90). The peak torque was determined for each movement. The strength deficit between the involved and uninvolved arms (patients) and the dominant and nondominant arms (control subjects) was calculated for each subject. Comparisons were made for the scapular-plane and 90-90 positions between isokinetic and HHD testing. Despite a normal muscle grade, patients had marked weakness (28% deficit, P weakness was not evident with isokinetic testing at the 90-90 position (60 degrees /s and 180 degrees /s, 0% deficit, P = .99). In control subjects, greater internal rotator strength in the dominant compared with the nondominant arm was evident with the HHD at the 90-90 position (11%, P muscle testing can quantify shoulder strength deficits that may not be apparent with isokinetic testing. By using an HHD during shoulder testing, clinicians can identify weakness that may have been presumed normal.

  13. Kinetic strategies of patients with shoulder impingement syndrome.

    Science.gov (United States)

    Doiron, Yan; Delacroix, Sébastien; Denninger, Marc; Simoneau, Martin

    2010-01-01

    Our aim was to determine whether subjects with shoulder impingement syndrome (SIS) have abnormal multijoint torque patterns compared to healthy subjects during normalized isometric force along specific directions. Subjects had to generate an isometric force corresponding to 40% of the maximal pain-free force. Eight targets were displayed on a monitor (0, 45, 90, 135, 180, 225, 270, and 315 degrees ). We calculated shoulder and elbow torques (kinetic strategies) using a biomechanical model. Regardless of the target location, the SIS group succeeded in reaching the target; however, when compared to the healthy subjects, they needed more time to do so, suggesting that SIS may slow down the execution of the kinetic strategies. Moreover, the SIS group produced lower shoulder external/internal torque to reach the targets located at 0 degrees and 225 degrees, and they generated greater abduction/adduction torque for targets located at 0, 135, and 180 degrees. In addition, they had lower elbow extension/flexion torque for the target located at 315 degrees. The investigation of atypical kinetic strategies is essential to provide an understanding of the pathomechanics of the SIS and to develop more effective treatment strategies.

  14. Editorial Commentary: Radiographic Inclusion and Exclusion Diagnostic Criteria for Femoroacetabular Impingement Require Confirmation.

    Science.gov (United States)

    Lubowitz, James H

    2015-07-01

    Femoroacetabular impingement radiographic diagnosis is a hot topic because sensitivity and specificity, and intraobserver and interobserver observational consistency, require confirmation. As a result, hip arthroscopic surgeons must rely on expert clinical examination.

  15. A SIMULATION STUDY OF DEPOSITION UNDER TWO TYPES OF IMPINGING TRAJECTORIES

    Institute of Scientific and Technical Information of China (English)

    X.Q. Wei; L. Zhou

    2004-01-01

    A model coupling particle aggregation and randomwalk surface diffusion has been developed for 2D simulation of depositionalgrowth, in which impinging particles follow either a straight-line trajectory of cosine distribution, representing typically sputter deposition, or a scattered trajectory, representing typically electrochemical deposition.Simulations of the growth under various impinging conditions and effective surface diffusivity have been carried out. Pattern and defect development in deposition on flat,trenched and ridged substrates have been investigated. We found that on flat and ridged substrates, both types of trajectories yield similar features, including formation of cone-like defects on surface ridges. While on trenched substrate, the straight-line impingement yielded more uniform step coverage than the scattered impingement.

  16. Clinical trials in orthopaedics and the future direction of clinical investigations for femoroacetabular impingement

    DEFF Research Database (Denmark)

    Clohisy, John C; Kim, Young-Jo; Lurie, Jon

    2013-01-01

    Femoroacetabular impingement (FAI) represents a heterogeneous group of disorders that affect a diverse patient population. The natural history of the disease, the role of nonsurgical management, the indications for surgery, optimal surgical techniques, and the predictors of treatment outcomes nee...

  17. Inter-examiner reproducibility of clinical tests and criteria to identify subacromial impingement syndrome

    DEFF Research Database (Denmark)

    Vind, Mikkel; Bogh, Søren Bie; Larsen, Camilla Marie;

    2011-01-01

    Abstract Introduction A specific algorithm has been proposed for classifying impingement related shoulder pain in athletes with overhead activity. Data on the inter-examiner reproducibility of the suggested clinical tests and criteria and their mutual dependencies for identifying subacromial...

  18. Impingement of lesser trochanter on ischium as a potential cause for hip pain

    Energy Technology Data Exchange (ETDEWEB)

    Patti, Jay W.; Ouellette, Hugue; Bredella, Miriam A.; Torriani, Martin [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Radiology, Boston, MA (United States)

    2008-10-15

    The bony anatomy of the hip leads to a limited array of impingement syndromes, more frequently resulting from abnormal contact between the femoral neck and acetabulum. We report an unusual case of osseous impingement between the lesser trochanter and ischium, with involvement of the intervening quadratus femoris muscle. While the prevalence and etiology of this finding is unclear, it may represent a cause for hip pain. (orig.)

  19. Shoulder Impingement, An Uncommon Complication of Distal Clavicle Fracture Treated Arthroscopically: A Case Report

    Directory of Open Access Journals (Sweden)

    CS Wang

    2013-11-01

    Full Text Available Clavicle fracture is commonly treated conservatively. However uncommon complication can arise causing impingement. We report a patient who sustained distal clavicle fracture and was treated conservatively. However he developed persistent shoulder pain that affected his daily life. Shoulder impingement was diagnosed and arthroscopic subacromioclavicular decompression was done. Following early physiotherapy the early recovery was good with full range of motion of the shoulder.

  20. Characterization of Reaerosolization From Impingers in an Effort to Improve Airborne Virus Sampling

    Science.gov (United States)

    2009-04-01

    the resultant deposition is therefore dictated by αi. A study on reaerosolization of Bacillus cereus bacterial spores from liquid impingers...impinger collection liquid can be expected to antagonize airborne virus collection efficiency, although the extent of this effect is not known. Therefore...concentration of Pseudomonas fluorescens vegetative cells and Bacillus subtilis spores from the BioSampler was about 20% of that from the AGI-30. The

  1. Stagnation-point flow of the Walters' B' fluid with slip

    OpenAIRE

    Labropulu, F.; Husain, I; Chinichian, M.

    2004-01-01

    The steady two-dimensional stagnation point flow of a non-Newtonian Walters' B' fluid with slip is studied. The fluid impinges on the wall either orthogonally or obliquely. A finite difference technique is employed to obtain solutions.

  2. Subacromial impingement in patients with whiplash injury to the cervical spine

    Directory of Open Access Journals (Sweden)

    Giddins Grey E

    2008-06-01

    Full Text Available Abstract Background Impingement syndrome and shoulder pain have been reported to occur in a proportion of patients following whiplash injuries to the neck. In this study we aim to examine these findings to establish the association between subacromial impingement and whiplash injuries to the cervical spine. Methods and results We examined 220 patients who had presented to the senior author for a medico-legal report following a whiplash injury to the neck. All patients were assessed for clinical evidence of subacromial impingement. 56/220 patients (26% had developed shoulder pain following the injury; of these, 11/220 (5% had clinical evidence of impingement syndrome. Only 3/11 patients (27% had the diagnosis made prior to evaluation for their medico-legal report. In the majority, other clinicians had overlooked the diagnosis. The seatbelt shoulder was involved in 83% of cases (p Conclusion After a neck injury a significant proportion of patients present with shoulder pain, some of whom have treatable shoulder pathology such as impingement syndrome. The diagnosis is, however, frequently overlooked and shoulder pain is attributed to pain radiating from the neck resulting in long delays before treatment. It is important that this is appreciated and patients are specifically examined for signs of subacromial impingement after whiplash injuries to the neck. Direct seatbelt trauma to the shoulder is one possible explanation for its aetiology.

  3. Hydrodynamics and PIV study in the impingement zone formed by a droplet train

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza; Zhang, Taolue; Muthusamy, Jayaveera; Alvarado, Jorge; Texas A; M University at Qatar Collaboration; Texas A; M University College Station Collaboration

    2016-11-01

    Droplet impingement is encountered in numerous technical applications, such as ink jet printing, spray cooling, and fuel injection in internal combustion engines. Even though many studies in droplet impingement were conducted in past, not many have measured the near-wall velocities in the droplet impingement zone. With the goal of gaining a better understanding of the hydrodynamics in the impingement zone, well-controlled experiments are performed in combination with micro-PIV measurements and numerical simulations. Hydrodynamics of HFE-7100 droplets generated using a piezoelectric droplet generator, impinging on a pre-wetted surface is investigated. Micro-PIV studies in the high-velocity impingement zone are performed using one-micron meter fluorescent particles dispersed in HFE-7100 along with the double exposed images. Three-dimensional and 2D-axisymmetric numerical modeling for a transient droplet crown development is performed. The interface between the gas and the liquid is modeled using a Volume of Fluid (VOF) method. Numerical simulation results obtained are observed to be in good agreement with that of the experimental observations. Supported by National Priority Research Program (NPRP) of Qatar National Research Fund (QNRF), Grant No.: NPRP 6-1304-2-525.

  4. Herniation pits and their renaissance in association with femoroacetabular impingement; Herniation Pits und ihre Renaissance im Zusammenhang mit femoroazetabulaerem Impingement

    Energy Technology Data Exchange (ETDEWEB)

    Panzer, Stephonie [Unfallklinik Murnau (Germany). Radiologie; Augat, P. [Unfallklinik Murnau (Germany). Radiologie; Paracelsus Univ. Salzburg (Austria). Biomechanisches Labor; Scheidler, J. [Radiologischs Zentrum Muenchen-Pasing (Germany). Radiologie

    2010-07-15

    Hernitation pits (HPs) of the femoral neck were first described in 1982. The purpose of this paper is to summarize the information concerning HPs published since then and to show their association with the diagnosis of femoroacetabular impingement (FAI) which has occurred within the last years. HPs are predominantly located at the anterior-superior femoral neck with a typical radiological appearance, which makes it possible to differentiate them from the numerous differential diagnoses mentioned. In the early publications HPs were described as a separate entity, while recent studies increasingly assign them to intra-osseous ganglia. In contrast to the early publications depicting HPs as an incidental finding, they are currently mainly mentioned in association with FAI and at the same time are partly considered to be a radiological indicator of FAI. In summary, HPs should always be recognized and documented because they may contribute to the diagnosis of FAI which is essential for preventing or delaying osteoarthritis of the hip joint in the early stage. (orig.)

  5. Hyperdense dots mimicking microcalcifications : Mammographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam Hyeon; Park, Jeong Mi; Goo, Hyun Woo; Bang, Sun Woo [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    1996-12-01

    To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy.

  6. Cervical spinal meningioma mimicking intramedullary spinal tumor.

    Science.gov (United States)

    Senturk, Senem; Guzel, Aslan; Guzel, Ebru; Bayrak, Aylin Hasanefendioğlu; Sav, Aydin

    2009-01-01

    Case report. To report a very unusual spinal meningioma, mimicking an intramedullary spinal tumor. Spinal meningiomas, usually associated with signs and symptoms of cord or nerve root compression, are generally encountered in women aged over 40. Radiologic diagnosis is often established by their intradural extramedullary location on magnetic resonance images. A 60-year-old woman had a 6-month history of progressive weakness in her upper extremities, difficulty in walking, and cervical pain radiating through both arms. Neurologic examination revealed motor strength deficiency in all her extremities, with extensor reflexes, clonus, and bilateral hyper-reflexiveness. A sensory deficit was present all over her body. Magnetic resonance images revealed that the spinal cord appeared expanded with an ill-defined, homogeneously contrast-enhanced, lobulated, eccentric mass at the C1-C3 level. The patient was operated with a preliminary diagnosis of an intramedullary tumor. At surgery, the mass was found to be extramedullary, and gross total resection was performed. Histopathological examination revealed a meningioma characterized by the presence of fibrous and meningothelial components. The patient was able to ambulate with a cane, and extremity strength and sensation improved 2 months after surgery. Spinal meningiomas can mimic intramedullary tumors, and should be considered in differential diagnosis of intradural tumors with atypical appearance.

  7. Lymphocitic infundibuloneurohypophysitis mimicking a pituitary adenoma

    Directory of Open Access Journals (Sweden)

    Hubertus Maximilian Mehdorn

    2011-04-01

    Full Text Available A rare case of infundibulo-neurohypophysitis mimicking a pituitary adenoma is presented. A 69-years-old female patient developed polyuria and polydipsia. Laboratory analysis revealed central diabetes insipidus. No hormonal abnormalities. Cranial-magnetic resonance imaging (MRI showed a left sided mass in the adenohypophysis presuming a pituitary adenoma. The mass had contact to both internal carotids. Admission to our department for neurosurgical treatment followed. Ophthalmo - logic examination and neurological examination yielded normal findings. A second MRI focussing on the sellar-region showed a leftsided (T2-MRI.hyperintense, distended adenohypophysis, without contrast enhancement in T1. The stalk appeared thickened. T1- weighted sequences of the neurohypophysis showed loss of signal intensity. We diagnosed an infundibulo-neurohypophysitis and abstai - ned from surgical removal. The patient was discharged under treatment with corticosteroids and desmopressin. Hypophysitis is rare and shows special clinical characteristics. Despite defined radiological features to differentiate between hypophysitis and adenoma the possibility of misdiagnosis, and unnecessary surgical procedures, should always kept in mind.

  8. Microfabricated adhesive mimicking gecko foot-hair

    Science.gov (United States)

    Geim, A. K.; Dubonos, S. V.; Grigorieva, I. V.; Novoselov, K. S.; Zhukov, A. A.; Shapoval, S. Yu.

    2003-07-01

    The amazing climbing ability of geckos has attracted the interest of philosophers and scientists alike for centuries. However, only in the past few years has progress been made in understanding the mechanism behind this ability, which relies on submicrometre keratin hairs covering the soles of geckos. Each hair produces a miniscule force ~10-7 N (due to van der Waals and/or capillary interactions) but millions of hairs acting together create a formidable adhesion of ~10 N cm-2: sufficient to keep geckos firmly on their feet, even when upside down on a glass ceiling. It is very tempting to create a new type of adhesive by mimicking the gecko mechanism. Here we report on a prototype of such 'gecko tape' made by microfabrication of dense arrays of flexible plastic pillars, the geometry of which is optimized to ensure their collective adhesion. Our approach shows a way to manufacture self-cleaning, re-attachable dry adhesives, although problems related to their durability and mass production are yet to be resolved.

  9. Hydroxychloroquine-associated hyperpigmentation mimicking elder abuse.

    Science.gov (United States)

    Cohen, Philip R

    2013-12-01

    Hydroxychloroquine may result in cutaneous dyschromia. Older individuals who are the victims of elder abuse can present with bruising and resolving ecchymoses. The features of hydroxychloroquine-associated hyperpigmentation are described, the mucosal and skin manifestations of elder abuse are reviewed, and the mucocutaneous mimickers of elder abuse are summarized. An elderly woman being treated with hydroxychloroquine for systemic lupus erythematosus developed drug-associated black and blue pigmentation of her skin. The dyschromia was misinterpreted by her clinician as elder abuse and Adult Protective Services was notified. The family was eventually cleared of suspected elder abuse. A skin biopsy of the patient's dyschromia confirmed the diagnosis of hydroxychloroquine-associated hyperpigmentation. Hyperpigmentation of skin, mucosa, and nails can be observed in patients treated with antimalarials, including hydroxychloroquine. Elder abuse is a significant and underreported problem in seniors. Cutaneous findings can aid in the discovery of physical abuse, sexual abuse, and self-neglect in elderly individuals. However, medication-associated effects, systemic conditions, and accidental external injuries can mimic elder abuse. Therefore, a complete medical history and appropriate laboratory evaluation, including skin biopsy, should be conducted when the diagnosis of elder abuse is suspected.

  10. Controlled Deposition of HAp Mimicking Tooth Enamel

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Chemical compositions and microsturcture of mature human tooth enamel were investigated by XRD , FTIR and SEM to further understand the characteristics of tooth enamel. In order to obtain apatite crystals chemically and structurally similar to those in tooth enamel, biomimetic way was employed. Selfassembled monolyers terminated with-SO3 H groups were used as deposition substrates and 1.5 SBF ( the concentrations of Ca2+ and PO43- ions 1.5 times than those in simulated body fluid ) with and without 5 ppm F- were used as soaking medium. The XRD and FTIR results showed that both the deposited fluoride-substituted hydroxyapatite( F-HAp ) crystals in 1.5 SBF with F- and hydroxyapatite ( HAp ) crystals in 1.5 SBF were carbonate-containing, mimicking human tooth enamel in chemical compositions. The SEM photos showed that needle-like F-HAp crystals bad large aspect ratios and grew in bundles, which were similar to the crystals in human tooth enamel.The results provide available information on dental restoration.

  11. Mimicking Bone - Chemical and Physical Challenges

    Directory of Open Access Journals (Sweden)

    Sophie C Cox

    2014-08-01

    Full Text Available It is known that chemical and physical features of bone contribute to its functionality, reactivity and mechanical performance. This fundamental rationale underpins the author’s research strategy. This paper presents a summary of efforts to fabricate a synthetic structure, referred to as a scaffold, that both chemically and physical emulates the intricate structure of bone. An understanding of key features of bone tissue that contribute to its remarkable properties is presented as a background to this work. Novel work aimed at improving the understanding of the synthesis of a ceramic biomaterial, namely hydroxyapatite, that is chemically similar to bone mineral is discussed. A case study involving the manufacture of porous scaffolds by 3D printing is also presented. In summary, this article highlights a number of on-going challenges that multidisciplinary tissue engineers aim to solve to get one step closer to mimicking bone, which clinically could improve the quality of life for millions of people worldwide.  Photo credit: By Doc. RNDr. Josef Reischig, CSc. (Author's archive [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0], via Wikimedia Commons

  12. Imaging of Posttraumatic Arthritis, Avascular Necrosis, Septic Arthritis, Complex Regional Pain Syndrome, and Cancer Mimicking Arthritis.

    Science.gov (United States)

    Rupasov, Andrey; Cain, Usa; Montoya, Simone; Blickman, Johan G

    2017-09-01

    This article focuses on the imaging of 5 discrete entities with a common end result of disability: posttraumatic arthritis, a common form of secondary osteoarthritis that results from a prior insult to the joint; avascular necrosis, a disease of impaired osseous blood flow, leading to cellular death and subsequent osseous collapse; septic arthritis, an infectious process leading to destructive changes within the joint; complex regional pain syndrome, a chronic limb-confined painful condition arising after injury; and cases of cancer mimicking arthritis, in which the initial findings seem to represent arthritis, despite a more insidious cause. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Hip Arthroscopy in athletes with Femoroacetabular Impingement: functional outcomes

    Science.gov (United States)

    Magi, Gonzalo; Carucci, Juan Pablo; Berro, Manuel; Bergues, Sebastián

    2017-01-01

    Introduction: Hip pathology is being recognized with more frequency as source of disability and functional limitation in athletes. It has been stated that the overload made with certain positions during some sports activities can develop condral damage. Moreover, the sum of bone deformity and repetitive movements of the hip requiered in sports may increase the risk of causing injuries. These can be treated with hip arthroscopy. Despite of this, there is a lack of evidence about the time taken to return to sports activity and the level reached afterwards by those patients treated with this procedure. Objective: Describe the clinical evolution, the time taken to return to sports activity and the level reached a year after the treatment of femoroacetabular impingement (FAI) with hip arthroscopy in 23 athletes. Method: 23 athletes were included in the study, defined as those patients with a minimum of 6 hours a week of sports practice, who were treated for FAI with hip arthroscopy between 2010 and 2015 by the same surgeon at our institution. The diagnosis was clinical (positive impingement test, hip pain and functional limitation of the hip), radiological (cam and pincer) and with magnetic nuclear resonance (labral tears). Preoperative modified Harris hip score was registered in all cases. Tonnis radiographic score was used. All patients had type 0 or 1 Tonnis hips. After 3 months of ineffective non operative treatment the arthroscopy was performed. Patients were treated in dorsal decubitus with orthopedic table. Labral reconstruction with anchors and femoral and acetabular osteoplasty was made. After surgery, patients were able to walk with support for 4 weeks and began physiotherapy. A year after surgery, all patients were questioned about the time taken to return to sports activity and the level of activity reached at that time compared to the one they had before symptoms appeared. The modified Harris hip score was also registered. Results: Ten patients played

  14. Non-harmful insertion of data mimicking computer network attacks

    Science.gov (United States)

    Neil, Joshua Charles; Kent, Alexander; Hash, Jr, Curtis Lee

    2016-06-21

    Non-harmful data mimicking computer network attacks may be inserted in a computer network. Anomalous real network connections may be generated between a plurality of computing systems in the network. Data mimicking an attack may also be generated. The generated data may be transmitted between the plurality of computing systems using the real network connections and measured to determine whether an attack is detected.

  15. Infrasellar craniopharyngioma mimicking a clival chordoma : a case report.

    Directory of Open Access Journals (Sweden)

    Kachhara R

    2002-04-01

    Full Text Available An unusual case of entirely infrasellar craniopharyngioma mimicking a clival chordoma is described. Only 22 cases of craniopharyngioma with nasopharyngeal extension have been reported in the literature. Of the reported cases, most were primarily intracranial with secondary downward extension; only two were thought to originate from an infrasellar location. The present case is another example of an entirely infrasellar craniopharyngioma, with extensive clival destruction, mimicking a clival chordoma. Relevant literature on the subject is reviewed.

  16. Water Impingement Erosion of Deep-Rolled Ti64

    Directory of Open Access Journals (Sweden)

    Dina Ma

    2015-08-01

    Full Text Available In this work, the Liquid Impingement Erosion (LIE performances of deep-rolling (DR treated and non-treated Ti64 were investigated. Various erosion stages, from the incubation to the terminal erosion stages, could be observed. A full factorial design of experiments was used to study the effect of DR process parameters (Feed Rate, Spindle Velocity, Number of Passes, Pressure on the residual stress distribution, microhardness and surface roughness of the treated Ti64 specimens. The DR-treated Ti64 specimens exhibited improved surface microhardness, surface roughness, and large magnitude of compressive residual stresses, which were attributed to the amount of cold work induced by the DR process. Although DR improved the mechanical properties of the Ti64, the results showed that the treatment has little or no effect on the LIE performance of Ti64 but different damage modes were observed in these two cases. Evolution of the erosion stages was described based on water-hammer pressure, stress waves, radial wall jetting, and hydraulic penetration modes. The initial erosion stages were mainly influenced by water-hammer pressure and stress waves, whereas the intermediate erosion stages were influenced by the combination of the four modes together. The final erosion stages contain the four modes, however the erosion was greatly driven by the radial jetting and hydraulic penetration modes, where more material was removed. The failure mechanism of the final stages of the LIE test of both DR-treated and non-treated Ti64 was characterized as fatigue fracture. However, a brittle fracture behavior was observed in the initial and intermediate erosion stages of the DR-treated Ti64, whereas a ductile fracture behavior was observed in the non-treated Ti64. This was concluded from the micrographs of the LIE damage through different erosion stages.

  17. Severe impingement of lumbar disc replacements increases the functional biological activity of polyethylene wear debris.

    Science.gov (United States)

    Baxter, Ryan M; Macdonald, Daniel W; Kurtz, Steven M; Steinbeck, Marla J

    2013-06-05

    Wear, oxidation, and particularly rim impingement damage of ultra-high molecular weight polyethylene total disc replacement components have been observed following surgical revision. However, neither in vitro testing nor retrieval-based evidence has shown the effect(s) of impingement on the characteristics of polyethylene wear debris. Thus, we sought to determine (1) differences in polyethylene particle size, shape, number, or biological activity that correspond to mild or severe rim impingement and (2) in an analysis of all total disc replacements, regardless of impingement classification, whether there are correlations between the extent of regional damage and the characteristics of polyethylene wear debris. The extent of dome and rim damage was characterized for eleven retrieved polyethylene cores obtained at revision surgery after an average duration of implantation of 9.7 years (range, 4.6 to 16.1 years). Polyethylene wear debris was isolated from periprosthetic tissues with use of nitric acid and was imaged with use of environmental scanning electron microscopy. Subsequently, particle size, shape, number, biological activity, and chronic inflammation scores were determined. Grouping of particles by size ranges that represented high biological relevance (<0.1 to 1-μm particles), intermediate biological relevance (1 to 10-μm particles), and low biological relevance (>10-μm particles) revealed an increased volume fraction of particles in the <0.1 to 1-μm and 1 to 10-μm size ranges in the mild-impingement cohort as compared with the severe-impingement cohort. The increased volume fractions resulted in a higher specific biological activity per unit particle volume in the mild-impingement cohort than in the severe-impingement cohort. However, functional biological activity, which is normalized by particle volume (mm3/g of tissue), was significantly higher in the severe-impingement cohort. This increase was due to a larger volume of particles in all three size

  18. Severe Impingement of Lumbar Disc Replacements Increases the Functional Biological Activity of Polyethylene Wear Debris

    Science.gov (United States)

    Baxter, Ryan M.; MacDonald, Daniel W.; Kurtz, Steven M.; Steinbeck, Marla J.

    2013-01-01

    Background: Wear, oxidation, and particularly rim impingement damage of ultra-high molecular weight polyethylene total disc replacement components have been observed following surgical revision. However, neither in vitro testing nor retrieval-based evidence has shown the effect(s) of impingement on the characteristics of polyethylene wear debris. Thus, we sought to determine (1) differences in polyethylene particle size, shape, number, or biological activity that correspond to mild or severe rim impingement and (2) in an analysis of all total disc replacements, regardless of impingement classification, whether there are correlations between the extent of regional damage and the characteristics of polyethylene wear debris. Methods: The extent of dome and rim damage was characterized for eleven retrieved polyethylene cores obtained at revision surgery after an average duration of implantation of 9.7 years (range, 4.6 to 16.1 years). Polyethylene wear debris was isolated from periprosthetic tissues with use of nitric acid and was imaged with use of environmental scanning electron microscopy. Subsequently, particle size, shape, number, biological activity, and chronic inflammation scores were determined. Results: Grouping of particles by size ranges that represented high biological relevance (10-μm particles) revealed an increased volume fraction of particles in the <0.1 to 1-μm and 1 to 10-μm size ranges in the mild-impingement cohort as compared with the severe-impingement cohort. The increased volume fractions resulted in a higher specific biological activity per unit particle volume in the mild-impingement cohort than in the severe-impingement cohort. However, functional biological activity, which is normalized by particle volume (mm3/g of tissue), was significantly higher in the severe-impingement cohort. This increase was due to a larger volume of particles in all three size ranges. In both cohorts, the functional biological activity correlated with the

  19. Use of an ultrasound blood-mimicking fluid for Doppler investigations of turbulence in vitro.

    Science.gov (United States)

    Thorne, Meghan L; Poepping, Tamie L; Rankin, Richard N; Steinman, David A; Holdsworth, David W

    2008-07-01

    Turbulence is an important factor in the assessment of stenotic disease and a possible causative mechanism for thromboembolism. Previous Doppler studies of turbulence have typically used whole-blood preparations or suspensions of erythrocytes. Recently, a water-glycerol based blood-mimicking fluid (BMF) has been developed for use in Doppler ultrasound studies. This fluid has desirable ultrasound properties but it has not previously been described during in vitro investigations of turbulence intensity. We report on investigations of grid-generated and constrained-jet turbulence in an in vitro test system. The BMF was found to generate significant levels of turbulence during steady flow at physiological flow rates, producing turbulent patterns in the distal region that were consistent with previous studies. Turbulence intensity increased significantly with flow rate (p fluid during in vitro investigations of turbulence using Doppler ultrasound.

  20. Noncavernous arteriovenous shunts mimicking carotid cavernous fistulae

    Science.gov (United States)

    Kobkitsuksakul, Chai; Jiarakongmun, Pakorn; Chanthanaphak, Ekachat; Singhara Na Ayudya, Sirintara (Pongpech)

    2016-01-01

    PURPOSE The classic symptoms and signs of carotid cavernous sinus fistula or cavernous sinus dural arteriovenous fistula (AVF) consist of eye redness, exophthalmos, and gaze abnormality. The angiography findings typically consist of arteriovenous shunt at cavernous sinus with ophthalmic venous drainage with or without cortical venous reflux. In rare circumstances, the shunts are localized outside the cavernous sinus, but mimic symptoms and radiography of the cavernous shunt. We would like to present the other locations of the arteriovenous shunt, which mimic the clinical presentation of carotid cavernous fistulae, and analyze venous drainages. METHODS We retrospectively examined the records of 350 patients who were given provisional diagnoses of carotid cavernous sinus fistulae or cavernous sinus dural AVF in the division of Interventional Neuroradiology, Ramathibodi Hospital, Bangkok between 2008 and 2014. Any patient with cavernous arteriovenous shunt was excluded. RESULTS Of those 350 patients, 10 patients (2.85%) were identified as having noncavernous sinus AVF. The angiographic diagnoses consisted of three anterior condylar (hypoglossal) dural AVF, two traumatic middle meningeal AVF, one lesser sphenoid wing dural AVF, one vertebro-vertebral fistula (VVF), one intraorbital AVF, one direct dural artery to cortical vein dural AVF, and one transverse-sigmoid dural AVF. Six cases (60%) were found to have venous efferent obstruction. CONCLUSION Arteriovenous shunts mimicking the cavernous AVF are rare, with a prevalence of only 2.85% in this series. The clinical presentation mainly depends on venous outflow. The venous outlet of the arteriovenous shunts is influenced by venous afferent-efferent patterns according to the venous anatomy of the central nervous system and the skull base, as well as by architectural disturbance, specifically, obstruction of the venous outflow. PMID:27767958

  1. On jet impingement and thin film breakup on a horizontal superhydrophobic surface

    Science.gov (United States)

    Prince, Joseph F.; Maynes, Daniel; Crockett, Julie

    2015-11-01

    When a vertical laminar jet impinges on a horizontal surface, it will spread out in a thin film. If the surface is hydrophobic and a downstream depth is not maintained, the film will radially expand until it breaks up into filaments or droplets. We present the first analysis and model that describes the location of this transition for both isotropic and anisotropic structured superhydrophobic (SH) surfaces. All surfaces explored are hydrophobic or SH, where the SH surfaces exhibit an apparent slip at the plane of the surface due to a shear free condition above the air filled cavities between the structures. The influence of apparent slip on the entire flow field is significant and yields behavior that deviates notably from classical behavior for a smooth hydrophilic surface where a hydraulic jump would form. Instead, break up into droplets occurs where the jet's outward radial momentum is balanced by the inward surface tension force of the advancing film. For hydrophobic surfaces, or SH surfaces with random micropatterning, the apparent slip on the surface is uniform in all directions and droplet breakup occurs in a circular pattern. When alternating rib/cavity microstructures are used to create the SH surface, the apparent slip varies as a function of the azimuthal coordinate, and thus, the breakup location is elliptically shaped. The thin film dynamics are modeled by a radial momentum analysis for a given jet Weber number and specified slip length and the location of breakup for multiple surfaces over a range of jet Weber numbers and realistic slip length values is quantified. The results of the analysis show that the breakup radius increases with increasing Weber number and slip length. The eccentricity of the breakup ellipse for the rib/cavity SH structures increases with increasing Weber number and slip length as well. A generalized model that allows prediction of the transition (break-up) location as a function of all influencing parameters is presented

  2. Impingement-free hip motion: the 'normal' angle alpha after osteochondroplasty.

    Science.gov (United States)

    Neumann, Mirjam; Cui, Quanjun; Siebenrock, Klaus A; Beck, Martin

    2009-03-01

    Femoroacetabular impingement is considered a cause of hip osteoarthrosis. In cam impingement, an aspherical head-neck junction is squeezed into the joint and causes acetabular cartilage damage. The anterior offset angle alpha, observed on a lateral crosstable radiograph, reflects the location where the femoral head becomes aspheric. Previous studies reported a mean angle alpha of 42 degrees in asymptomatic patients. Currently, it is believed an angle alpha of 50 degrees to 55 degrees is normal. The aim of this study was to identify that angle alpha which allows impingement-free motion. In 45 patients who underwent surgical treatment for femoroacetabular impingement, we measured the angle alpha preoperatively, immediately postoperatively, and 1 year postoperatively. All hips underwent femoral correction and, if necessary, acetabular correction. The correction was considered sufficient when, in 90 degrees hip flexion, an internal rotation of 20 degrees to 25 degrees was possible. The angle alpha was corrected from a preoperative mean of 66 degrees (range, 45 degrees - 79 degrees) to 43 degrees (range, 34 degrees - 60 degrees) postoperatively. Because the acetabulum is corrected to normal first, the femoral correction is tested against a normal acetabulum. We therefore concluded an angle alpha of 43 degrees achieved surgically and with impingement-free motion, represents the normal angle alpha, an angle lower than that currently considered sufficient.

  3. The plain beta-angle measured on radiographs in the assessment of femoroacetabular impingement.

    Science.gov (United States)

    Brunner, A; Hamers, A T; Fitze, M; Herzog, R F

    2010-09-01

    The beta-angle is a radiological tool for measuring the distance between the pathological head-neck junction and the acetabular rim with the hip in 90 degrees of flexion in patients with femoroacetabular impingement. Initially it was measured using an open-chamber MRI. We have developed a technique to measure this angle on plain radiographs. Correlation analysis was undertaken to determine the relationship between the range of movement and the beta-angle in 50 patients with femoroacetabular impingement and 50 asymptomatic control subjects. Inter- and intra-observer reliability of the beta-angle was also evaluated. Patients with femoroacetabular impingement had a significantly smaller (p angle (15.6 degrees, 95% confidence interval (CI) 13.3 to 17.7) compared with the asymptomatic group (38.7 degrees, 95% CI 36.5 to 41.0). Correlation between internal rotation and the beta-angle was high in the impingement group and moderate in the asymptomatic group. The beta-angle had excellent inter- and intra-observer reliability in both groups. Our findings suggest that the measurement of the beta-angle on plain radiography may represent a valid, reproducible and cost-effective alternative to open MRI in the assessment of the pathological bony anatomy in patients with cam, pincer and mixed femoroacetabular impingement.

  4. Is there a relationship between psoas impingement and increased trochanteric retroversion?

    Science.gov (United States)

    Gómez-Hoyos, Juan; Schröder, Ricardo; Reddy, Manoj; Palmer, Ian J; Khoury, Anthony; Martin, Hal David

    2015-07-01

    The concept of psoas impingement secondary to a tight or inflamed iliopsoas tendon causing impingement of the anterior labrum during hip extension has been suggested. The purpose of this study was to assess the relationship between the lesser trochanteric version (LTV) in symptomatic patients with psoas impingement as compared with asymptomatic hips. The femoral neck version (FNV) and LTV were evaluated on axial magnetic resonance imaging, as well as the angle between LTV and FNV. Data from 12 symptomatic patients and 250 asymptomatic patients were analysed. The mean, range and standard deviations were calculated. Independent t-tests were used to determine differences between groups. The lesser trochanteric retroversion was significantly increased in patients with psoas impingement as compared with asymptomatic hips (-31.1° SD ± 6.5 versus -24.2° ± 11.5, P  0.05) and the angle between FNV and LTV (40.2° ± 9.7 versus 38.3° ± 9.6, P > 0.05) were not significantly different between groups. In conclusion, the lesser trochanteric retroversion is significantly increased in patients with psoas impingement as compared with asymptomatic hips.

  5. Isometric contractions combined with eccentric contractions and stretching exercises on patient with subacromial impingement syndrome

    Directory of Open Access Journals (Sweden)

    Efstratiadis Anastasios

    2015-10-01

    Full Text Available Many people with shoulder pain and disability have signs of subacromial impingement syndrome. The subacromial impingement syndrome of the shoulder is a general term, which is often used to describe pain and dysfunction in the area around the shoulder. The aim of the present report is to find the effect of isometric contractions combined with eccentric contractions and stretching exercises on a patient with subacromial impingement syndrome. A patient with subacromial impingement syndrome for 1 year was included in the case report. The patient followed an exercise program consisted of stretching exercises of shoulder muscles extensors, isometric contractions of shoulder extensors and eccentric exercises of shoulder extensors, 4 times per week. The exercise program was individualized according to pain and symptoms of the patient. Outcome measures were pain, pain rest, pain activity, pain night measured on a visual analogue scale (VAS, disability index (DASH score and range of motion (Goniometer. The patient was evaluated at baseline and after 4 weeks. At the end of the program, there was a significant improvement pain, disability and range of motion. In this clinical case the patient was improved significantly in all outcome measures. Further studies based on better design, are needed to investigate the effect of those methods on a random population group with subacromial impingement syndrome.

  6. Impact of impingement on the Hudson River white perch population. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Barnthouse, L.W.; Van Winkle, W.; Kirk, B.L.; Vaughan, D.S.

    1982-02-01

    This report summarizes a series of analyses of the magnitude and biological significance of the impingement of white perch at the Indian Point Nuclear Generating Station and other Hudson River power plants. Included in these analyses were evaluations of: (1) two independent lines of evidence relating to the magnitude of impingement impacts on the Hudson River white perch population; (2) the additional impact caused by entrainment of white perch; (3) data relating to density-dependent growth among young-of-the-year white perch; (4) the feasibility of performing population-level analyses of impingement impacts on the white perch populations of Chesapeake Bay and the Delaware River; and (5) the feasibility of using simple food chain and food web models to evaluate community-level effects of impingement and entrainment. Estimated reductions in the abundances of the 1974 and 1975 white perch year classes, caused by impingement and entrainment, were high enough that the possibility of adverse long-term effects cannot be excluded.

  7. Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a slot air jet

    Science.gov (United States)

    Adimurthy, M.; Katti, Vadiraj V.

    2016-06-01

    Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a normal slot air jet is experimental investigated. Present study focuses on the influence of jet-to-plate spacing (Z/D h ) (0.5-10) and Reynolds number (2500-20,000) on the fluid flow and heat transfer distribution. A single slot jet with an aspect ratio (l/b) of about 22 is chosen for the current study. Infrared Thermal Imaging technique is used to capture the temperature data on the target surface. Local heat transfer coefficients are estimated from the thermal images using `SMART VIEW' software. Wall static pressure measurement is carried out for the specified range of Re and Z/D h . Wall static pressure coefficients are seen to be independent of Re in the range between 5000 and 15,000 for a given Z/D h . Nu values are higher at the stagnation point for all Z/D h and Re investigated. For lower Z/D h and higher Re, secondary peaks are observed in the heat transfer distributions. This may be attributed to fluid translating from laminar to turbulent flow on the target plate. Heat transfer characteristics are explained based on the simplified flow assumptions and the pressure data obtained using Differential pressure transducer and static pressure probe. Semi-empirical correlation for the Nusselt number in the stagnation region is proposed.

  8. Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a slot air jet

    Science.gov (United States)

    M, Adimurthy; Katti, Vadiraj V.

    2017-02-01

    Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a normal slot air jet is experimental investigated. Present study focuses on the influence of jet-to-plate spacing ( Z/D h ) (0.5-10) and Reynolds number (2500-20,000) on the fluid flow and heat transfer distribution. A single slot jet with an aspect ratio ( l/b) of about 22 is chosen for the current study. Infrared Thermal Imaging technique is used to capture the temperature data on the target surface. Local heat transfer coefficients are estimated from the thermal images using `SMART VIEW' software. Wall static pressure measurement is carried out for the specified range of Re and Z/D h . Wall static pressure coefficients are seen to be independent of Re in the range between 5000 and 15,000 for a given Z/D h . Nu values are higher at the stagnation point for all Z/D h and Re investigated. For lower Z/D h and higher Re, secondary peaks are observed in the heat transfer distributions. This may be attributed to fluid translating from laminar to turbulent flow on the target plate. Heat transfer characteristics are explained based on the simplified flow assumptions and the pressure data obtained using Differential pressure transducer and static pressure probe. Semi-empirical correlation for the Nusselt number in the stagnation region is proposed.

  9. Deriving a blood-mimicking fluid for particle image velocimetry in Sylgard-184 vascular models.

    Science.gov (United States)

    Yousif, Majid Y; Holdsworth, David W; Poepping, Tamie L

    2009-01-01

    A new blood-mimicking fluid (BMF) has been developed for particle image velocimetry (PIV), which enables flow studies in vascular models (phantoms). A major difficulty in PIV that affects measurement accuracy is the refraction and distortion of light passing through the interface between the model and the fluid, due to the difference in refractive index (n) between the two materials. The problem can be eliminated by using a fluid with a refractive index matching that of the model. Such fluids are not commonly available, especially for vascular research where the fluid should also have a viscosity similar to human blood. In this work, a blood-mimicking fluid, composed of water (47.38% by weight), glycerol (36.94% by weight) and sodium iodide salt (15.68% by weight), was developed for compatibility with our silicone (Sylgard 184; n = 1.414) phantoms. The fluid exhibits a dynamic viscosity of 4.31+/-0.03 cP which lies within the range of human blood viscosity (4.4+/-0.6 cP). Both refractive index and viscosity were attained at 22.2+/-0.2 degrees C, which is a feasible room temperature, thus eliminating the need for a temperature-control system. The fluid will be used to study hemodynamics in vascular flow models fabricated from Sylgard 184.

  10. Restless legs syndrome mimicking S1 radiculopathy.

    Science.gov (United States)

    Zambelis, Th; Wolgamuth, B R; Papoutsi, S N; Economou, N T

    2016-01-01

    mimicking several pathological conditions, Restless Legs Syndrome prevalence on general population according to various large epidemiological studies and pathogenic hypotheses on the issue of Restless Legs Syndrome are discussed. Finally, by presenting another possible "RLS-mimic" our aim is to highlight the common misdiagnosis of Restless Legs Syndrome, which can mimic a variety of disorders, some of which are very common, such as an S1 radiculopathy, thus raising concern among doctors of various specialties addressed to by Restless Legs Syndrome sufferers, on the importance of proper diagnosis of the syndrome.

  11. Modeling of the Flow, Temperature and Concentration Fields in an Arc Plasma Reactor with Argon-Nitrogen Atmosphere

    National Research Council Canada - National Science Library

    Fudolig, Agustin M; Nogami, Hiroshi; Yagi, Jun-ichiro

    1996-01-01

    A mathematical formulation was developed for describing the flow behavior, temperature profile and concentration fields in pure or mixed argon and nitrogen arc plasmas impinging on a metal target inside a reactor...

  12. Mimicking the humpback whale: An aerodynamic perspective

    Science.gov (United States)

    Aftab, S. M. A.; Razak, N. A.; Mohd Rafie, A. S.; Ahmad, K. A.

    2016-07-01

    This comprehensive review aims to provide a critical overview of the work on tubercles in the past decade. The humpback whale is of interest to aerodynamic/hydrodynamic researchers, as it performs manoeuvres that baffle the imagination. Researchers have attributed these capabilities to the presence of lumps, known as tubercles, on the leading edge of the flipper. Tubercles generate a unique flow control mechanism, offering the humpback exceptional manoeuverability. Experimental and numerical studies have shown that the flow pattern over the tubercle wing is quite different from conventional wings. Research on the Tubercle Leading Edge (TLE) concept has helped to clarify aerodynamic issues such as flow separation, tonal noise and dynamic stall. TLE shows increased lift by delaying and restricting spanwise separation. A summary of studies on different airfoils and reported improvement in performance is outlined. The major contributions and limitations of previous work are also reported.

  13. Long-term monitoring dataset of fish assemblages impinged at nuclear power plants in northern Taiwan.

    Science.gov (United States)

    Chen, Hungyen; Liao, Yun-Chih; Chen, Ching-Yi; Tsai, Jeng-I; Chen, Lee-Sea; Shao, Kwang-Tsao

    2015-12-08

    The long-term species diversity patterns in marine fish communities are garnering increasing attention from ecologists and conservation biologists. However, current databases on quantitative abundance information lack consistent long-term time series, which are particularly important in exploring the possible underlying mechanism of community changes and evaluating the effectiveness of biodiversity conservation measures. Here we describe an impinged fish assemblage dataset containing 1, 283, 707 individuals from 439 taxa. Once a month over 19 years (1987-1990 and 2000-2014), we systematically collected the fish killed by impingement upon cooling water intake screens at two nuclear power plants on the northern coast of Taiwan. Because impingement surveys have low sampling errors and can be carried out over many years, they serve as an ideal sampling tool for monitoring how fish diversity and community structure vary over an extended period of time.

  14. "Simultaneous measurement of flame impingement and piston surface temperatures in an optically accessible spark ignition engine"

    Science.gov (United States)

    Ding, Carl-Philipp; Honza, Rene; Böhm, Benjamin; Dreizler, Andreas

    2017-04-01

    This paper shows the results of spatially resolved temperature measurements of the piston surface of an optically accessible direct injection spark ignition engine during flame impingement. High-speed thermographic phosphor thermometry (TPT), using Gd3Ga5O12:Cr,Ce, and planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) were used to investigate the temperature increase and the time and position of flame impingement at the piston surface. Measurements were conducted at two operating cases and showed heating rates of up to 16,000 K/s. The OH-PLIF measurements were used to localize flame impingement and calculate conditioned statistics of the temperature profiles. The TPT coating was characterized and its influence on the temperature measurements evaluated.

  15. Nanofluid jet impingement heat transfer characteristics in the rectangular mini-fin heat sink

    Science.gov (United States)

    Naphon, Paisarn; Nakharintr, Lursukd

    2012-11-01

    The nanofluid jet impingement heat transfer characteristics in a rectangular mini-fin heat sink are studied. The heat sink is fabricated from aluminum by a wire electrical discharge machine. The nanofluid is a mixture of deionized water and nanoscale TiO2 particles with a volume nanoparticle concentration of 0.2%. The results obtained for nanofluid jet impingement cooling in the rectangular mini-fin heat sink are compared with those found in the water jet impingement cooling. The effects of the inlet temperature of the nanofluid, its Reynolds number, and the heat flux on the heat transfer characteristics of the rectangular mini-fin heat sink are considered. It is found that the average heat transfer rates for the nanofluid as coolant are higher than those for deionized water.

  16. Pheochromocytoma mimicking an acute myocardial infarction.

    NARCIS (Netherlands)

    Menke-van der Houven van Oordt, C.W.; Twickler, T.B.; Asperdt, F.G. van; Ackermans, P.; Timmers, H.J.L.M.; Hermus, A.R.M.M.

    2007-01-01

    We report a 42-year-old female who presented with retrosternal pain, dyspnoea and nausea. Electrocardiography suggested a recent anterior myocardial infarction. However, emergency coronary angiography showed normal blood flow through all the coronary arteries. Paroxysmal hypertension raised the susp

  17. Trunk and lower limb biomechanics during stair climbing in people with and without symptomatic femoroacetabular impingement.

    Science.gov (United States)

    Hammond, Connor A; Hatfield, Gillian L; Gilbart, Michael K; Garland, S Jayne; Hunt, Michael A

    2017-02-01

    Femoroacetabular impingement is a pathomechanical hip condition leading to pain and impaired physical function. It has been shown that those with femoroacetabular impingement exhibit altered gait characteristics during level walking and stair climbing, and decreased muscle force production during isometric muscle contractions. However, no studies to-date have looked at trunk kinematics or muscle activation during dynamic movements such as stair climbing in this patient population. The purpose of this study was to compare biomechanical outcomes (trunk and lower limb kinematics as well as lower limb kinetics and muscle activation) during stair climbing in those with and without symptomatic femoroacetabular impingement. Trunk, hip, knee and ankle kinematics, as well as hip, knee and ankle kinetics and muscle activity of nine lower limb muscles were collected during stair climbing for 20 people with clinical and radiographic femoroacetabular impingement and compared to 20 age- and sex-matched pain-free individuals. Those with femoroacetabular impingement ascended the stairs slower (effect size=0.82), had significantly increased peak trunk forward flexion angles (effect size=0.99) and external hip flexion moments (effect size=0.94) and had decreased peak external knee flexion moments (effect size=0.90) compared to the control group. Findings from this study indicate that while those with and without femoroacetabular impingement exhibit many biomechanical similarities when ascending stairs, differences in trunk forward flexion and joint kinetics indicate some important differences. Further longitudinal research is required to elucidate the cause of these differences as well as the clinical relevance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Flow coherent structures and frequency signature: application of the dynamic modes decomposition to open cavity flow

    Energy Technology Data Exchange (ETDEWEB)

    Lusseyran, F; Gueniat, F; Basley, J; Douay, C L; Pastur, L R; Faure, T M [LIMSI-CNRS BP 133, F-91403 Orsay Cedex (France); Schmid, P J [LadHyX, Ecole Polytechnique, F-91128 Palaiseau (France)

    2011-12-22

    The dynamic dimension of an impinging flow may be significantly reduced by its boundary conditions and self-sustained oscillations they induce. The spectral signature is associated with remarkable spatial coherent structures. Dynamic modes decomposition (DMD) makes it possible to directly extract the dynamical properties of a non-linearly saturated flow. We apply DMD to highlight the spectral contribution of the longitudinal and transverse structures of an experimental open-cavity flow.

  19. Exploration of Impinging Water Spray Heat Transfer at System Pressures Near the Triple Point

    Science.gov (United States)

    Golliher, Eric L.; Yao, Shi-Chune

    2013-01-01

    The heat transfer of a water spray impinging upon a surface in a very low pressure environment is of interest to cooling of space vehicles during launch and re-entry, and to industrial processes where flash evaporation occurs. At very low pressure, the process occurs near the triple point of water, and there exists a transient multiphase transport problem of ice, water and water vapor. At the impingement location, there are three heat transfer mechanisms: evaporation, freezing and sublimation. A preliminary heat transfer model was developed to explore the interaction of these mechanisms at the surface and within the spray.

  20. An unusual cause of the quadrilateral space impingement syndrome by a bone spike

    Energy Technology Data Exchange (ETDEWEB)

    Amin, Mohammed F.; Berst, Matthew; El-Khoury, George Y. [University of Iowa Hospitals and Clinics, Radiology, Iowa City, IO (United States)

    2006-12-15

    The quadrilateral space impingement syndrome is a clinical syndrome resulting from compression of the axillary nerve and the posterior circumflex humeral artery, with subsequent focal atrophy of the teres minor, with or without involvement of portions of the deltoid muscle. This entity has many etiologies. We are reporting a case of this syndrome caused by a bone spike from a malunited old scapular fracture following a motor vehicle accident. The bone spike impinged on the axillary nerve as it passes through the quadrilateral space, causing focal atrophy of the teres minor muscle. The abnormality was well demonstrated by MD-CT. (orig.)

  1. The role of femoroacetabular impingement in core muscle injury/athletic pubalgia: diagnosis and management

    Directory of Open Access Journals (Sweden)

    Thomas eEllis

    2016-02-01

    Full Text Available Chronic groin pain in athletes represents a major diagnostic and therapeutic challenge in sports medicine. Two recognized causes of inguinal pain in the young adult athlete are core muscle injury/athletic pubalgia (CMI/AP and femoroacetabular impingement (FAI. CMI/AP and FAI were previously considered to be two distinct entities, however recent studies have suggested both entities to frequently coincide in the athlete with groin pain. This article briefly discusses the role of femoroacetabular impingement in core muscle injury/athletic pubalgia, and the diagnosis and management of this complex disease.

  2. Glyceryl trinitrate patches—An alternative treatment for shoulder impingement syndrome

    Directory of Open Access Journals (Sweden)

    Yusuf Assem

    2015-01-01

    Full Text Available Transdermal glyceryl trinitrate patches have been investigated as an alternative therapeutic intervention for a range of tendinopathies, due to the ease of titration of dosage and the ease of their application. Glyceryl trinitrate has been inferred to reduce pain and inflammation secondary to their nitric oxide-producing action. Shoulder impingement syndrome is a soft tissue condition that manifests as anterior shoulder pain, weakness, and difficulty in daily activities. This review will evaluate the efficacy of glyceryl trinitrate patches in treating a variety of rotator cuff tendinopathies related to shoulder impingement, based on human and animal trials, and suggest its practical application in future trials and management.

  3. Mimicking liver sinusoidal structures and functions using a 3D-configured microfluidic chip.

    Science.gov (United States)

    Du, Yu; Li, Ning; Yang, Hao; Luo, Chunhua; Gong, Yixin; Tong, Chunfang; Gao, Yuxin; Lü, Shouqin; Long, Mian

    2017-02-28

    Physiologically, four major types of hepatic cells - the liver sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, and hepatocytes - reside inside liver sinusoids and interact with flowing peripheral cells under blood flow. It is hard to mimic an in vivo liver sinusoid due to its complex multiple cell-cell interactions, spatiotemporal construction, and mechanical microenvironment. Here we developed an in vitro liver sinusoid chip by integrating the four types of primary murine hepatic cells into two adjacent fluid channels separated by a porous permeable membrane, replicating liver's key structures and configurations. Each type of cells was identified with its respective markers, and the assembled chip presented the liver-specific unique morphology of fenestration. The flow field in the liver chip was quantitatively analyzed by computational fluid dynamics simulations and particle tracking visualization tests. Intriguingly, co-culture and shear flow enhance albumin secretion independently or cooperatively, while shear flow alone enhances HGF production and CYP450 metabolism. Under lipopolysaccharide (LPS) stimulations, the hepatic cell co-culture facilitated neutrophil recruitment in the liver chip. Thus, this 3D-configured in vitro liver chip integrates the two key factors of shear flow and the four types of primary hepatic cells to replicate key structures, hepatic functions, and primary immune responses and provides a new in vitro model to investigate the short-duration hepatic cellular interactions under a microenvironment mimicking the physiology of a liver.

  4. Mesalamine treatment mimicking relapse in a child with ulcerative colitis

    Institute of Scientific and Technical Information of China (English)

    Iva Hojsak; Ana M Pavić; Sanja Kolaček

    2014-01-01

    Background: There are reports on mesalamine-induced bloody diarrhea mimicking ulcerative colitis (UC) relapse, mostly in adults. Methods: Herein we present a case of a child with UC who developed relapse of hemorrhagic colitis related to mesalamine. Results: A 10-year-old girl developed severe symptoms mimicking UC relapse 3 weeks after introduction of mesalamine therapy. After mesalamine was withdrawn, her symptoms improved, but deteriorated again during the challenge of mesalamine despite concomitant use of corticosteroids. Conclusion: This is the fi rst case report on such a young child during the concomitant use of corticosteroids.

  5. Design of Gages for Direct Skin Friction Measurements in Complex Turbulent Flows with Shock Impingement Compensation

    Science.gov (United States)

    2007-06-07

    www.ansys.com/ 30 Figliola, p. 87-91. 31 Pilkey, p. 564. 32 Fogiel, p. 1112. 33 Hibbeler , R.C. Engineering Mechanics Static and Dynamics 5th Edition...Macmillan Publishing Company, Inc., New York, 1989 pp. 486, 511. 34 Hibbeler , pp. 486, 511. 35 Figliola, p. 89. 36 Fogiel, p. 258. 37

  6. Detailed flowfield and surface properties for high Knudsen number planar jet impingement at an inclined flat plate

    Science.gov (United States)

    Cai, Chunpei; He, Xin

    2016-05-01

    This paper presents two sets of analytical exact solutions for collisionless gas flows from a planar exit, impinging at an inclined flat plate. These analytical results are obtained by using gaskinetic theories. The first set of solutions are for a diffuse reflective plate surface, and the other set of solutions are for a specular reflective plate surface. A virtual nozzle exit is adopted to aid analyzing the specular reflective plate scenario. New formulas for plate surface properties, including velocity slips, pressure, shear stress, and heat flux distributions, are provided. For both problems, the flowfield exact solutions are investigated as well. Numerical simulations with the direct simulation Monte Carlo method are performed to validate these new analytical results, and good agreement is obtained for flows with high Knudsen numbers. The results consider effects from many factors, such as the plate inclination angle, geometry ratios, and exit gas and plate properties (such as exit gas bulk density, gas speed ratio, and exit gas and plate temperatures). Compared with past work, these new solutions are more comprehensive and practical. The results also illustrate that if the plate is quite close to the nozzle exit, it is improper to adopt the traditional treatments of a point source and a simple cosine function.

  7. Observations on the use of membrane filtration and liquid impingement to collect airborne microorganisms in various atmospheric environments

    Science.gov (United States)

    Griffin, Dale W.; Gonzalez, C.; Teigell, N.; Petrosky, T.; Northup, D.E.; Lyles, M.

    2011-01-01

    The influence of sample-collection-time on the recovery of culturable airborne microorganisms using a low-flow-rate membrane-filtration unit and a high-flow-rate liquid impinger were investigated. Differences in recoveries were investigated in four different atmospheric environments, one mid-oceanic at an altitude of ~10.0 m, one on a mountain top at an altitude of ~3,000.0 m, one at ~1.0 m altitude in Tallahassee, Florida, and one at ~1.0 m above ground in a subterranean-cave. Regarding use of membrane filtration, a common trend was observed: the shorter the collection period, the higher the recovery of culturable bacteria and fungi. These data also demonstrated that lower culturable counts were common in the more remote mid-oceanic and mountain-top atmospheric environments with bacteria, fungi, and total numbers averaging (by sample time or method categories) filtration for aeromicrobiology studies if start-up costs are not an issue and temperature permits use; (2) although membrane filtration is more cost friendly and has a 'typically' wider operational range, its limits include loss of cell viability with increased sample time and issues with effectively extracting nucleic acids for community-based analyses; (3) the ability to recover culturable microorganisms is limited in 'extreme' atmospheric environments and thus the use of a 'limited' methodology in these environments must be taken into account; and (4) the atmosphere culls, i.e., everything is not everywhere. ?? 2010 US Government.

  8. Funiculitis mimicking appendicitis: A rare culprit

    Directory of Open Access Journals (Sweden)

    Lindsey L. Perea

    2017-01-01

    Full Text Available Acute appendicitis is an extremely common cause for pediatric admissions, most notably presenting with right lower quadrant pain. There are few other etiologies for a young male to have pain aside from appendicitis. We present a young boy who presented with right lower quadrant abdominal pain and fevers, but was found to have funiculitis. Funiculitis, or inflammation of the spermatic cord, is a very rare condition in the pediatric population, almost always occurring in the elderly with urinary flow conditions. We share our case to remind providers the importance of a full differential diagnosis.

  9. Computational Analysis of Droplet Mass and Size Effect on Mist/Air Impingement Cooling Performance

    Directory of Open Access Journals (Sweden)

    Zhenglei Yu

    2013-01-01

    Full Text Available Impingement cooling has been widely employed to cool gas turbine hot components such as combustor liners, combustor transition pieces, turbine vanes, and blades. A promising technology is proposed to enhance impingement cooling with water droplets injection. However, previous studies were conducted on blade shower head film cooling, and less attention was given to the transition piece cooling. As a continuous effort to develop a realistic mist impingement cooling scheme, this paper focuses on simulating mist impingement cooling under typical gas turbine operating conditions of high temperature and pressure in a double chamber model. Furthermore, the paper presents the effect of cooling effectiveness by changing the mass and size of the droplets. Based on the heat-mass transfer analogy, the results of these experiments prove that the mass of 3E – 3 kg/s droplets with diameters of 5–35 μm could enhance 90% cooling effectiveness and reduce 122 K of wall temperature. The results of this paper can provide guidance for corresponding experiments and serve as the qualification reference for future more complicated studies with convex surface cooling.

  10. A new radiological index for assessing asphericity of the femoral head in cam impingement

    DEFF Research Database (Denmark)

    Gosvig, K K; Jacobsen, S; Palm, H;

    2007-01-01

    Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip. The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (alpha) angle and the tria...

  11. An Experimental Method for Measuring Water Droplet Impingement Efficiency on Two- and Three-dimensional Bodies

    Science.gov (United States)

    Papadakis, M.; Zumwalt, G. W.; Elangonan, R.; Freund, G. A., Jr.; Breer, M.; Whitmer, L.

    1989-01-01

    An experimental method was developed to determine the droplet impingement characteristics on 2-D and 3-D bodies. The experimental results provide the essential droplet impingement data required to validate water droplet trajectory codes, which are used in the analysis of aircraft icing. A body, whose water droplet impingement characteristics are required, is covered at strategic locations by thin strips of moisture absorbing (blotter) paper, and is exposed to an air stream containing a water dye solution spray cloud. Water droplet impingement data are extracted from the dyed blotter strips by measuring the optical reflectance of the dye deposit on the strips, using an automated reflectometer. Models tested include a 4-inch diameter cylinder, a NACA 652015 airfoil section, a MS(1)-0317 supercritical airfoil section, three simulated ice shapes, an axisymmetric inlet and a Boeing 737-300 inlet model. Detailed descriptions of the dye tracer technique, instrumentation, data reduction method and the results obtained are presented. Analytical predictions of collection efficiency characteristics for most test configurations are included for comparison.

  12. Electron emission yields from boron-like Ar ions impinging on Au(100)

    NARCIS (Netherlands)

    Bodewits, E.; Bekker, H.; de Nijs, A. J.; Hoekstra, R.; Winklehner, D.; Daniel, B.; Kowarik, G.; Dobes, K.; Aumayr, F.

    2011-01-01

    Using a new experimental station to be installed at the HITRAP facility at GSI we studied electron emission yields of Ar13+ ions impinging on a clean Au(1 00) surface. By taking data under different incidence angles and at different initial kinetic energies, contributions from kinetic and potential

  13. Analysis of disagreement between numerically predicted and experimental heat transfer data of impinging jet

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ping; YE Liang-chun; ZHOU Jie-min; YANG Ying

    2006-01-01

    The method of numerical simulation was applied to investigate the effects of jet impinging plate thickness and its thermal conductivity on the local heat flux distribution along the impinging plate. The results show that the two factors have great effects on the heat flux distribution. The non-uniformity of the local heat-flux on the impinging plate surface gets more profound as the plate becomes thicker and thermal conductivity gets larger. When Reynand even for the plate with only 25 μm in thickness, the non-uniformity of the heat flux cannot be neglected. When approximately treated as an iso-heat-flux boundary. In the experimental research, a real non-iso-heat-flux boundary is treated as an iso-heat-flux boundary, which would result in under-estimated Nusselt number value in the stagnation zone and an over-estimated value outside. Such an experimental Nusselt number distribution is taken to evaluate turbulent model, and the conclusion would be drawn that the turbulent model over-predicts the stagnation heat transfer. This is one of the important reasons why many literatures reported that k-ε turbulent model dramatically over-predicts the impinging jet heat transfer in the stagnation region.

  14. Role of kinetic energy of impinging molecules in the α-sexithiophene growth

    NARCIS (Netherlands)

    Tonezzer, M.; Rigo, E.; Gottardi, S.; Bettotti, P.; Pavesi, L.; Iannotta, S.; Toccoli, T.

    2011-01-01

    We report on the α-sexithiophene sub-monolayer growth with supersonic molecular beam deposition by investigating how the kinetic energy of the impinging molecules influences the growth on substrates with different surface wettabilities and temperatures. The results show that the energy of the

  15. A new radiological index for assessing asphericity of the femoral head in cam impingement

    DEFF Research Database (Denmark)

    Gosvig, K K; Jacobsen, S; Palm, H

    2007-01-01

    Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip. The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (alpha) angle and the tria...

  16. Role of the confinement of a root canal on jet impingement during endodontic irrigation

    NARCIS (Netherlands)

    Verhaagen, B.; Boutsioukis, C.; Heijnen, G. L.; van der Sluis, L. W. M.; Versluis, M.

    2012-01-01

    During a root canal treatment the root canal is irrigated with an antimicrobial fluid, commonly performed with a needle and a syringe. Irrigation of a root canal with two different types of needles can be modeled as an impinging axisymmetric or non-axisymmetric jet. These jets are investigated exper

  17. Subacute posteromedial impingement of the ankle in athletes: MR imaging evaluation and ultrasound guided therapy

    Energy Technology Data Exchange (ETDEWEB)

    Messiou, Christina; Robinson, Philip; O' Connor, Philip J.; Grainger, Andrew [Leeds Teaching Hospitals, St. James University Hospital, Department of Radiology, Leeds (United Kingdom)

    2006-02-15

    To describe the use of MR imaging and efficacy of ultrasound-guided steroid injection in the diagnosis and management of athletes with clinical posteromedial impingement of the ankle. A retrospective analysis of imaging findings on MR was undertaken in nine elite athletes with clinical posteromedial ankle impingement. MR studies from six professional athletes with posterolateral pain were also reviewed as an imaging control group. The two reviewing radiologists were blinded to the clinical details and the proportion of control and study subjects. The nine study athletes also underwent diagnostic ultrasound and ultrasound-guided injection of steroid and anaesthetic into the posteromedial capsular abnormality. Follow-up was by telephone interview. Posteromedial capsular thickening was seen only in athletes with posteromedial impingement (7/9). Posteromedial synovitis was present in all athletes with posteromedial impingement; however, posterior and posterolateral synovitis was also seen in these athletes. Mild posteromedial synovitis was present in two control athletes. Ultrasound identified abnormal posteromedial soft tissue thickening deep to tibialis posterior between the medial malleolus and talus in all nine athletes. After injection all athletes returned to their previous level of sport, with eight of the nine not experiencing any residual or recurrent symptoms. If MR imaging excludes significant coexistent abnormality, ultrasound can localise posteromedial soft tissue abnormality and guide injection therapy, allowing return to athletic activity without surgical intervention. (orig.)

  18. Detection of airborne Legionella while showering using liquid impingement and fluorescent in situ hybridization (FISH).

    Science.gov (United States)

    Deloge-Abarkan, Magali; Ha, Thi-Lan; Robine, Enric; Zmirou-Navier, Denis; Mathieu, Laurence

    2007-01-01

    Aerosols of water contaminated with Legionella bacteria constitute the only mode of exposure for humans. However, the prevention strategy against this pathogenic bacteria risk is managed through the survey of water contamination. No relationship linked the Legionella bacteria water concentration and their airborne abundance. Therefore, new approaches in the field of the metrological aspects of Legionella bioaerosols are required. This study was aimed at testing the main principles for bioaerosol collection (solid impaction, liquid impingement and filtration) and the in situ hybridization (FISH) method, both in laboratory and field assays, with the intention of applying such methodologies for airborne Legionella bacteria detection while showering. An aerosolization chamber was developed to generate controlled and reproducible L. pneumophila aerosols. This tool allowed the identification of the liquid impingement method as the most appropriate one for collecting airborne Legionella bacteria. The culturable fraction of airborne L. pneumophila recovered with the liquid impingement principle was 4 and 700 times higher compared to the impaction and filtration techniques, respectively. Moreover, the concentrations of airborne L. pneumophila in the impinger fluid were on average 7.0 x 10(5) FISH-cells m(-3) air with the fluorescent in situ hybridization (FISH) method versus 9.0 x 10(4) CFU m(-3) air with the culture method. These results, recorded under well-controlled conditions, were confirmed during the field experiments performed on aerosols generated by hot water showers in health institutions. This new approach may provide a more accurate characterization of aerobiocontamination by Legionella bacteria.

  19. Iliopsoas impingement after revision total hip arthroplasty treated with iliopsoas muscle transection.

    Science.gov (United States)

    Morohashi, Itaru; Homma, Yasuhiro; Kanda, Akio; Yamamoto, Yasuhiro; Obata, Hiroyuki; Mogami, Atsuhiko; Obayashi, Osamu; Kaneko, Kazuo

    2016-05-01

    Iliopsoas tendinitis after revision total hip arthroplasty (THA) is rare and its etiology and optimal treatment are still unclear. We report a case of iliopsoas impingement after revision THA with a Kerboull acetabular reinforcement device requiring two-level iliopsoas muscle transection. A 70-year-old woman presented to our hospital complaining of debilitating right groin pain after revision THA with a Kerboull reinforcement device. She had undergone multiple hip operations after experiencing a pelvic fracture in a motor vehicle accident. A lidocaine nerve block at the level of the Kerboull device resulted in temporary but marked reduction in pain and a diagnosis of psoas impingent. We performed surgery via an anterior approach to release the iliopsoas muscle from the lesser trochanter. After iliopsoas tenotomy was performed, the muscle was still under high tension because of dense adhesions. Repeat transection of the iliopsoas muscle at the level of the anterior branch of the Kerboull device resulted in loosening of the iliopsoas muscle and resolution of impingement. Postoperatively, the patient's groin pain completely disappeared, and she can now walk with a single cane and is satisfied with her result. Adhesions around the iliopsoas muscle likely contributed to the patient's groin pain. Open surgery to perform complete release of iliopsoas muscle impingement should be considered in patients with pain after revision THA. We reported a patient with Iliopsoas tendinitis after revision THA requiring two-level iliopsoas muscle transection.

  20. Modeling of soft impingement effect during solid-state partitioning phase transformations in binary alloys

    NARCIS (Netherlands)

    Chen, H.; Van der Zwaag, S.

    2010-01-01

    The soft impingement effect at the later stage of partitioning phase transformations has been modeled both for the diffusion-controlled growth model and for the mixed-mode model. Instead of the linear and exponential approximations for the concentration gradient in front of the interface used in the

  1. Clinical outcomes assessment in clinical trials to assess treatment of femoroacetabular impingement

    DEFF Research Database (Denmark)

    Harris-Hayes, Marcie; McDonough, Christine M; Leunig, Michael

    2013-01-01

    Patient-reported outcome measures are an important component of outcomes assessment in clinical trials to assess the treatment of femoroacetabular impingement (FAI). This review of disease-specific measures and instruments used to assess the generic quality of life and physical activity levels...

  2. Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome

    DEFF Research Database (Denmark)

    Larsen, C M; Søgaard, Karen; Chreiteh, S S

    2013-01-01

    Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population with and w...

  3. Primary Papillary Mucinous Adenocarcinoma of the Ureter Mimicking Genitourinary Tuberculosis

    Directory of Open Access Journals (Sweden)

    Hanni Gulwani

    2010-01-01

    Full Text Available Primary adenocarcinomas of the renal pelvis and ureter are rare and account for less than 1% of all malignancies at this site. We report a case of primary papillary mucinous adenocarcinoma of the ureter that clinically mimicked genitourinary tuberculosis. Early diagnosis is important for the better outcome.

  4. Osteoid osteoma of the radial styloid mimicking de quervain tenosynovitis.

    Science.gov (United States)

    Chloros, George D; Themistocleous, George S; Papagelopoulos, Panayiotis J; Khaldi, Lubna; Efstathopoulos, Dimitrios G; Soucacos, Panayotis N

    2007-10-01

    A very unusual location of osteoid osteoma arising in the radial styloid is presented, which strongly mimicked de Quervain tenosynovitis, thereby resulting in the patient undergoing an additional unnecessary operation and a substantial delay of more than 2 years in diagnosis.

  5. Spinal MRI of vincristine neuropathy mimicking Guillain-Barre syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yun Woo; Yoon, Hye-Kyung; Cho, Jae Min [Department of Radiology, Samsung Medical Centre, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Kangnam-gu, Seoul 135-710 (Korea); Sung, Ki Woong [Department of Paediatrics, Samsung Medical Centre, Seoul 135-710 (Korea)

    2003-11-01

    A 4.3-year-old girl with acute leukaemia, who was being treated with chemotherapy (including vincristine), developed paraplegia. Spinal MRI showed diffusely enhancing nerve roots on contrast-enhanced images. Spinal fluid analysis showed a normal protein level. Vincristine neuropathy mimicking Guillain-Barre syndrome is thought to be the cause of the MRI abnormalities. (orig.)

  6. Calcified Klatskin tumor mimicking intrahepatic stone: case report.

    Science.gov (United States)

    Park, H S; Han, J K; Lee, H S; Lee, K H; Kim, S H; Kim, K W; Kim, Y J; Kim, H-C; Choi, B I

    2005-01-01

    Calcification is a relatively uncommon manifestation of malignant liver neoplasm. Calcifications in peripheral cholangiocarcinomas but not in Klatskin tumor have been reported. We present a rare case of Klatskin tumor that had dystrophic calcification mimicking a intrahepatic stone in a 65-year-old man.

  7. Achromobacter xylosoxidans infection presenting as a pulmonary nodule mimicking cancer.

    Science.gov (United States)

    Claassen, Stephanie L; Reese, Jason M; Mysliwiec, Vincent; Mahlen, Steven D

    2011-07-01

    Achromobacter xylosoxidans is typically isolated from pulmonary sources, presenting as pneumonia in immunosuppressed individuals. We describe a novel clinical presentation of A. xylosoxidans infection presenting as multiple spiculated, pulmonary nodules mimicking cancer for which the patient underwent a wedge resection of the lung for diagnosis and staging of presumptive cancer.

  8. Cutaneous lymphoid hyperplasia mimicking cutaneous lymphoma in a hyperthyroid cat.

    Science.gov (United States)

    Snead, Elisabeth; Kerr, Moira; Macdonald, Valerie

    2013-10-01

    A 12-year-old neutered male domestic shorthair cat presented for chronic, localized, swelling and crusting of the left upper lip, weight loss, sporadic vomiting, and focal alopecia between the scapulae was diagnosed with hyperthyroidism and regional eosinophilic lymphadenitis. Treatment with methimazole exacerbated an underlying hypersensitivity disorder leading to marked generalized lymphadenopathy that histologically mimicked lymphoma.

  9. Diffuse Large B Cell Lymphoma Mimicking Granulomatosis with Polyangiitis

    Science.gov (United States)

    Horowitz, Netanel; Ben-Itzhak, Ofer; Braun-Moscovici, Yolanda

    2016-01-01

    In a patient with systemic multiorgan disease with overlapping features, the differential diagnosis included infectious diseases, malignancies, and systemic autoimmune or inflammatory diseases. We present an unusual case of a young male with B cell lymphoma who presented with symptoms mimicking systemic vasculitis and review the existing literature. PMID:27293945

  10. Adenomatoid odontogenic tumour mimicking a periapical cyst in pregnant woman

    DEFF Research Database (Denmark)

    Kothari, Mohit; Bhandari, Neha

    2010-01-01

    EJ, Murrah VA. Adenomatoid odontogenic tumor presenting as periapical disease. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:557-60) and is associated with the crown of an impacted tooth, commonly the maxillary canine. We present a rare case of extrafollicular AOT mimicking a periapical...

  11. Trichophyton Schoenleinii-induced widespread tinea corporis mimicking parapsoriasis.

    Science.gov (United States)

    Mansouri, P; Farshi, S; Khosravi, A R; Naraghi, Z S; Chalangari, R

    2012-06-01

    We report a case of extensive tinea corporis in an 80-year-old woman on her forearms, thighs, legs, buttocks and trunk, mimicking parapsoriasis due to Trichophyton schoenleinii, without scalp involvement. Diagnosis of Trichophyton schoenleinii was confirmed by microscopy and mycological culture specimens.

  12. Calcific Tendinosis: A Potential Mimicker of Malignancy on PET

    OpenAIRE

    Vogel-Claussen, Jens; Morrison, William; Zoga, Adam; Bergin, Diane; Gopez, Angela; Fayad, Laura M.

    2015-01-01

    We report a case of a 53 year old female with breast cancer and elevated glucose activity at the left greater trochanter on PET imaging. Further imaging with CT and MRI showed that this focus of increased FDG activity on PET was calcific tendinosis of the gluteus medius tendon, which mimicked metastatic disease in this patient.

  13. Headache attributed to unruptured saccular aneurysm, mimicking hemicrania continua.

    Science.gov (United States)

    Vikelis, Michail; Xifaras, Michail; Magoufis, Georgios; Gekas, Georgios; Mitsikostas, Dimos Dimitrios

    2005-06-01

    Unruptured cerebral arterial aneurysms most often remain asymptomatic, but they may cause headache or other symptoms or signs. We describe herewith a case of headache attributed to an unruptured internal carotid artery aneurysm, clearly mimicking the phenotype of hemicrania continua. Potential pathophysiological explanations and recommendations for recognition of similar cases are discussed.

  14. Diffuse Large B Cell Lymphoma Mimicking Granulomatosis with Polyangiitis

    Directory of Open Access Journals (Sweden)

    Mohammad E. Naffaa

    2016-01-01

    Full Text Available In a patient with systemic multiorgan disease with overlapping features, the differential diagnosis included infectious diseases, malignancies, and systemic autoimmune or inflammatory diseases. We present an unusual case of a young male with B cell lymphoma who presented with symptoms mimicking systemic vasculitis and review the existing literature.

  15. Ablation characteristics of special concrete due to an impinging zirconium-dioxide melt jet

    Energy Technology Data Exchange (ETDEWEB)

    An, S.M., E-mail: sangmoan@kaeri.re.kr; Ha, K.S.; Min, B.T.; Kim, H.Y.; Song, J.H.

    2015-04-01

    Highlights: • The jet impingement tests were performed for a special concrete of core-catcher. • The ablation rate and depth were measured 1.59 mm/s and 4.33 mm, respectively. • The experimental results were estimated well between the model prediction bounds. • The material ablation was described reasonably by a convective heat transfer model. - Abstract: Jet impingement experiments were performed to investigate the ablation characteristics of special concrete, which has been developed as one of the candidate protecting materials for the EU-APR1400 ex-vessel core catcher. In order to simulate the jet impingement phenomenon owing to the reactor vessel failure during a severe core meltdown accident, the experimental facility was established and the experimental conditions were determined based on parametric studies. The special concrete specimen was manufactured in accordance with the standard procedures, and its microstructures and physicochemical properties were analyzed to verify the requirements for the qualification. An induction melting technique in a cold crucible was employed to generate the zirconium-dioxide melt as a simulant of the corium melt. The special concrete was ablated uniformly over the impact area by jet impingement, and the average ablation depth was measured to be 4.33 mm. The average ablation rate in depth was evaluated as 1.59 mm/s using the temperature measurements of the specimen. As compared with the predictions by the models based on the convective and radiative heat transfer analysis, both the measured ablation rate and depth were estimated appropriately within the bounds of their limits. However, the convective heat transfer model turned out to predict the ablation characteristics of the special concrete more reasonably during the jet impingement even though some water content within the special concrete could lead to a sudden generation of the steam layer through which the material ablation is attenuated substantially by the

  16. Unusual Diaphragmatic Hernias Mimicking Cardiac Masses

    Science.gov (United States)

    Kim, Si Hun; Kim, Myoung Gun; Kim, Su Ji; Moon, Jeonggeun; Kang, Woong Chol; Shin, Mi-Seung

    2015-01-01

    Hiatal hernia and Morgagni hernia are sorts of diaphragmatic hernias that are rarely detected on transthoracic echocardiography. Although echocardiographic findings have an important role for differential diagnosis of cardiac masses, we often might overlook diaphragmatic hernia. We report three cases of diaphragmatic hernias having specific features. The first case is huge hiatal hernia that encroaches left atrium with internal swirling flow on transthoracic echocardiography. The second case is a hiatal hernia that encroaches on both atria, incidentally detected on preoperative echocardiography. The third case is Morgagni hernia which encroaches on the right atrium only. So, we need to consider possibility of diaphragmatic hernia when we find a cardiac mass with specific echocardiographic features. PMID:26140154

  17. Laboratory studies of stagnating plasma flows with applications to inner solar system and stellar bow shocks

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2016-10-01

    Supercritical magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe by converting flow kinetic energy to other forms such as thermal and supra-thermal populations, magnetic field enhancement, turbulence, and energetic particles. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those of inner solar system and stellar bow shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to 100s of km/s; resulting in β 1, collisionless plasma flows with Msonic and MAlfvén 10. The drifting FRC can be made to impinge upon a variety of static obstacles including: a strong mirror or cusp magnetic field (mimicking magnetically excited shocks such as the Earth's bow shock), plasma pileup from a solid obstacle (similar to the bow shocks of Mercury and the Moon), and a neural gas puff (bow shocks of Venus or the comets). Characteristic shock length and time scales that are both large enough to observe yet small enough to fit within the experiment, enabling study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental program will be presented, including recent results. This work is supported by the U.S. DOE, Office of Science, Office of Fusion Energy Sciences under Contract No. DE-AC52-06NA25369.

  18. Acoustic Assessment of a Konjac–Carrageenan Tissue-Mimicking Material at 5–60 MHz

    Science.gov (United States)

    Kenwright, David A.; Sadhoo, Neelaksh; Rajagopal, Srinath; Anderson, Tom; Moran, Carmel M.; Hadoke, Patrick W.; Gray, Gillian A.; Zeqiri, Bajram; Hoskins, Peter R.

    2014-01-01

    The acoustic properties of a robust tissue-mimicking material based on konjac–carrageenan at ultrasound frequencies in the range 5–60 MHz are described. Acoustic properties were characterized using two methods: a broadband reflection substitution technique using a commercially available preclinical ultrasound scanner (Vevo 770, FUJIFILM VisualSonics, Toronto, ON, Canada), and a dedicated high-frequency ultrasound facility developed at the National Physical Laboratory (NPL, Teddington, UK), which employed a broadband through-transmission substitution technique. The mean speed of sound across the measured frequencies was found to be 1551.7 ± 12.7 and 1547.7 ± 3.3 m s−1, respectively. The attenuation exhibited a non-linear dependence on frequency, f (MHz), in the form of a polynomial function: 0.009787f2 + 0.2671f and 0.01024f2 + 0.3639f, respectively. The characterization of this tissue-mimicking material will provide reference data for designing phantoms for preclinical systems, which may, in certain applications such as flow phantoms, require a physically more robust tissue-mimicking material than is currently available. PMID:25438864

  19. Os acromiale causing shoulder impingement syndrome: a case report; Os acromiale como causa de impingement del hombro: a proposito de un caso

    Energy Technology Data Exchange (ETDEWEB)

    Romero, I.; Rodriguez, A.; Roca, M.; Garcia, Y. [Hospital Universitario Miguel Servet. Zaragoza (Spain)

    2001-07-01

    Shoulder impingement syndrome is caused by repeated mechanical trauma to the rotator cuff due to encroachment of the coracoacromial ligement; in most cases, it is a primary lesion. Os acromiale, an anatomic variant of the shoulder structures, is one of the predisposing factors for the development of this entity. We present a case of os acromiale complicated by complete rupture of the tendon of the supraspinatus muscle and luxation of the long head of the biceps tendon. We stress the importance of magnetic resonance in the study of this anatomic variant and in the detection of complications or associated lesions. (Author) 10 refs.

  20. Giant arachnoid granulation mimicking dural sinus thrombosis.

    Science.gov (United States)

    Ayaz, Ercan; Atalay, Basak; Baysal, Begumhan; Senturk, Senem; Aslan, Ahmet

    2017-01-01

    Arachnoid granulations (AG) are composed of dense, collagenous connective tissue that includes clusters of arachnoid cells. They tend to invaginate into the dural sinuses, through which cerebrospinal fluid enters the venous system. AG are most commonly seen at the junction between the middle and lateral thirds of the transverse sinuses near the entry sites of the superficial veins. Presently described is the case of a 21-year-old female who presented at the clinic with recurrent headaches. Magnetic resonance (MR) imaging revealed a 3.5-cm lesion, which extended from confluens sinuum through the superior sagittal sinus. The lesion had created a scallop-shaped area of erosion in the neighboring occipital bone. To exclude sinus thrombosis, MR venography was performed, which displayed a maintained venous flow around the lesion. Headaches were treated symptomatically with medical therapy. Giant AG can be misdiagnosed as dural sinus thrombosis. MR imaging combined with MR venography is the most useful diagnostic tool to differentiate giant AG from dural sinus thrombosis.

  1. Osteoblastic Metastases Mimickers on Contrast Enhanced CT

    Directory of Open Access Journals (Sweden)

    Fahad Al-Lhedan

    2017-01-01

    Full Text Available Secondary osseous involvement in lymphoma is more common compared to primary bone lymphoma. The finding of osseous lesion can be incidentally discovered during the course of the disease. However, osseous metastases are infrequently silent. Detection of osseous metastases is crucial for accurate staging and optimal treatment planning of lymphoma. The aim of imaging is to identify the presence and extent of osseous disease and to assess for possible complications such as pathological fracture of the load-bearing bones and cord compression if the lesion is spinal. We are presenting two patients with treated lymphoma who were in complete remission. On routine follow-up contrast enhanced CT, there were new osteoblastic lesions in the spine worrisome for metastases. Additional studies were performed for further evaluation of both of them which did not demonstrate any corresponding suspicious osseous lesion. The patients have a prior history of chronic venous occlusive thrombosis that resulted in collaterals formation. Contrast enhancement of the vertebral body marrow secondary to collaterals formation and venous flow through the vertebral venous plexus can mimic the appearance of spinal osteoblastic metastases.

  2. A Case of Acute Motor Axonal Neuropathy Mimicking Brain Death and Review of the Literature.

    Science.gov (United States)

    Ravikumar, Sandhya; Poysophon, Poysophon; Poblete, Roy; Kim-Tenser, May

    2016-01-01

    We describe a case report of fulminant Guillain-Barré syndrome (GBS) mimicking brain death. A previously healthy 60-year-old male was admitted to the neurointensive care unit after developing rapidly progressive weakness and respiratory failure. On presentation, the patient was found to have absent brainstem and spinal cord reflexes resembling that of brain death. Acute motor axonal neuropathy, a subtype of GBS, was diagnosed by cerebrospinal fluid and nerve conduction velocity testing. An electroencephalogram showed that the patient had normal, appropriately reactive brain function. Transcranial Doppler (TCD) ultrasound showed appropriate blood flow to the brain. GBS rarely presents with weakness so severe as to mimic brain death. This article provides a review of similar literature. This case demonstrates the importance of performing a proper brain death examination, which includes evaluation for irreversible cerebral injury, exclusion of any confounding conditions, and performance of tests such as electroencephalography and TCDs when uncertainty exists about the reliability of the clinical exam.

  3. Numerical investigation on the flow structures in a narrow confined channel with staggered jet array arrangement

    Directory of Open Access Journals (Sweden)

    Liu Haiyong

    2015-12-01

    Full Text Available A series of numerical analyses have been performed to investigate the flow structures in a narrow confined channel with 12 staggered circular impingement holes and one bigger exit hole. The flow enters the channel through the impingement holes and exits through the far end outlet. The flow fields corresponding to two jet Reynolds numbers (25000 and 65000 and three channel configurations with different ratios of the channel height to the impingement hole diameter (Zr = 1, 3, 5 are analyzed by solving the Reynolds averaged Navier–Stokes equations with the realizable k–ε turbulence model. Detailed flow field information including the secondary flow, the interaction between the jets and the cross flow, and flow distribution along the channel has been obtained. Comparisons between the numerical and experimental results of the flow fields at the four planes along the channel are performed to validate the numerical method. The calculated impingement pattern, high velocity flow distribution, low velocity separation region and vortices are in good agreement with the experimental data, implying the validity and effectiveness of the employed numerical approach for analyzing relevant flow field.

  4. Numerical heat transfer during partially-confined, confined, and free liquid jet impingement with rotation and chemical mechanical planarization process modeling

    Science.gov (United States)

    Lallave Cortes, Jorge C.

    This work presents the use of numerical modeling for the analysis of transient and steady state liquid jet impingement for cooling application of electronics, and energy dissipation during a CMP process under the influence of a series of parameters that controls the transport phenomena mechanism. Seven thorough studies were done to explore how the flow structure and conjugated heat transfer in both the solid and fluid regions was affected by adding a secondary rotational flow during the jet impingement process. Axis-symmetrical numerical models of round jets with a spinning or static nozzle were developed using the following configurations: confined, partially-confined, and free liquid jet impingement on a rotating or stationary uniformly heated disk of finite thickness and radius. Calculations were done for various materials, namely copper, silver, Constantan, and silicon with a solid to fluid thermal conductivity ratio covering a range of 36.91.2222, at different laminar Reynolds numbers ranging from 220 to 2,000, under a broad rotational rate range of 0 to 1,000 RPM (Ekman number=infinity--3.31x10--5), nozzle-to-plate spacing (beta=0.25.5.0), dimensionless disk thicknesses (b/dn=0.167.1.67), confinement ratio (rp/rd=0.2.0.75), and Prandtl number (1.29.124.44) using NH3, H2O, FC.77 and MIL.7808 as working fluids. An engineering correlation relating the average Nusselt number with the above parameters was developed for the prediction of system performance. The simulation results compared reasonably well with previous experimental studies. The second major contribution of this research was the development of a three dimensional CMP model that shows the temperature distributions profile as an index of energy dissipation at the wafer and pad surfaces, and slurry interface. A finite element analysis was done with FIDAP 8.7.4 package under the influence of physical parameters, such as slurry flow rates (0.5.1.42 cc/s), polishing pressures (17.24.41.37 kPa), pad

  5. Thermal Characteristics of Air-Water Spray Impingement Cooling of Hot Metallic Surface under Controlled Parametric Conditions

    Institute of Scientific and Technical Information of China (English)

    Santosh Kumar Nayak; Purna Chandra Mishra

    2016-01-01

    Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper.The controlling input parameters investigated were the combined air and water pressures,plate thickness,water flow rate,nozzle height from the target surface and initial temperature of the hot surface.The effects of these input parameters on the important thermal characteristics such as heat transfer rate,heat transfer coefficient and wetting front movement were measured and examined.Hot flat plate samples of mild steel with dimension 120 mm in length,120 mm breadth and thickness of 4 mm,6 mm,and 8 mm respectively were tested.The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface.Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e,4 mm thick plates.Increase in the nozzle height reduced the heat transfer efficiency of spray cooling.At an inlet water pressure of 4 bar and air pressure of 3 bar,maximum cooling rates 670℃/s and average cooling rate of 305.23℃/s were achieved for a temperature of 850℃ of the steel plate.

  6. Density Models for Velocity Analysis of Jet Impinged CEDM Missile

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Won Ho; Kang, Tae Kyo; Cho, Yeon Ho; Chang, Sang Gyoon; Lee, Dae Hee [KEPCO EnC, Daejeon (Korea, Republic of)

    2015-05-15

    A control element drive mechanism (CEDM) can be a potential missile in the reactor head area during one of the postulated accidents. The CEDM is propelled by the high speed water jet discharged from a broken upper head nozzle. The jet expansion models to predict the missile velocity have been investigated by Kang et al. The previous work of Kang et al. showed a continuous increase in missile velocity as the CEDM missile travels. But it is not natural in that two phase flow from the nozzle break exit tends to disperse and the thrust force on the missile decreases along the distance of the travel. The jet flow also interacts with the air surrounding itself. Therefore, the density change has to be included in the estimation of the missile velocity. In this paper, two density change models of the water jet are introduced for the jet expansion models along with the distance from the nozzle break location. The first one is the direct approximation model. Two density approximation models are introduced to predict the CEDM missile velocity. For each model, the effects of the expanded jet area were included as the area ratio to the exit nozzle area. In direct approximation model, the results have showed rapid decrease in both density and missile velocity. In pressure approach model, the density change is assumed perfectly proportional to the pressure change, and the results showed relatively smooth change in both density and missile velocity comparing to the direct approximation model. Using the model developed by Kang et al.., the maximum missile velocity is about 4 times greater comparing to the pressure approach model since the density is constant as the jet density at the nozzle exit in their model. Pressure approach model has benefits in that this model adopted neither curve fitting nor extrapolation unlike the direct approximation model, and included the effects of density change which are not considered in the model developed by Kang et al. So, this model is

  7. Granuloma inguinale mimicking as squamous cell carcinoma of penis

    Directory of Open Access Journals (Sweden)

    Abhishek Pilani

    2014-01-01

    Full Text Available Granuloma inguinale (GI is an acquired chronic, slowly progressive, mildly contagious disease of venereal origin, characterized by granulomatous ulceration of the genitalia and neighboring sites, with little or no tendency to spontaneous healing caused by Klebsiella (Calymmatobacterium granulomatis. A 55-year-old male presented with fissured, foul smelling, fungating growth over prepuce with phimosis mimicking squamous cell carcinoma (SCC without lymphadenopathy. It started with painless papulonodular showed pseudoepitheliomatous hyperplasia, infiltration in dermis, acanthosis and vacuolated macrophages suggestive of GI and not showing any histopathological features of SCC. Patient was successfully treated by giving cotrimoxazole twice a day for 21 days. Here, we presented a case of GI mimicking SCC of penis, which was diagnosed on basis of histopathology and treated with excision followed by medical therapy with cotrimoxazole.

  8. Addison's Disease Mimicking as Acute Pancreatitis: A Case Report.

    Science.gov (United States)

    Chaudhuri, Sayani; Rao, Karthik N; Patil, Navin; Ommurugan, Balaji; Varghese, George

    2017-04-01

    Over past two decades there has been significant improvement in medical field in elucidating the underlying pathophysiology and genetics of Addison's disease. Adrenal insufficiency (Addison's disease) is a rare disease with an incidence of 0.8/100,000 cases. The diagnosis may be delayed if the clinical presentation mimics a gastrointestinal disorder or psychiatric illness. We report a case of Addison's disease presenting as acute pain in abdomen mimicking clinical presentation of acute pancreatitis.

  9. Osteofibrous dysplasia of clavicle clinically mimicking chronic osteomyelitis

    Directory of Open Access Journals (Sweden)

    Nirmal Raj Gopinathan

    2016-01-01

    Full Text Available Osteofibrous dysplasia or ossifying fibroma is an uncommon benign fibro-osseous lesion of childhood, commonly described in the maxilla and the mandible. Among long bones, it usually presents in the tibia as a painless swelling or anterior bowing. Ossifying fibroma of clavicle has never been reported in English literature, to the best of our knowledge. Here, we would like to present an unusual case of osteofibrous dysplasia of clavicle clinically mimicking chronic osteomyelitis.

  10. Localized IgG4-related Cholecystitis Mimicking Gallbladder Cancer.

    Science.gov (United States)

    Inoue, Tadahisa; Okumura, Fumihiro; Mizushima, Takashi; Nishie, Hirotada; Iwasaki, Hiroyasu; Anbe, Kaiki; Ozeki, Takanori; Kachi, Kenta; Fukusada, Shigeki; Suzuki, Yuta; Watanabe, Kazuko; Sano, Hitoshi

    2015-01-01

    We encountered a case of localized IgG4-cholecystitis mimicking gallbladder cancer with focal/segmental type1 autoimmune pancreatitis (AIP). In this case, we were unable to exclude a diagnosis of gallbladder cancer and thus performed radical cholecystectomy. Type1 AIP is often associated with gallbladder lesions, accompanied by generally diffuse, circumferential thickening of the gallbladder wall. Although localized IgG4-related cholecystitis is extremely rare, differentiating this condition from gallbladder cancer is often very difficult.

  11. An Adolescent Patient with Scabies Mimicking Gottron Papules

    OpenAIRE

    Eiji Yoshinaga; Naoki Oiso; Shigeru Kawara; Akira Kawada

    2009-01-01

    Atypical features of scabies occur in infants and children and patients with prolonged use of corticosteroids or immunosuppression. We report a non-immunosuppressed 15-year-old female case of scabies showing scaly reddish papules over the proximal interphalangeal joints mimicking Gottron papules in classic dermatomyositis. Periungal erythema was also seen. Four months’ topical corticosteroids from previous clinics had been used. Dermoscopic findings were consistent with typical pictures of sc...

  12. Embryonal rhabdomyosarcoma of the biliary tree mimicking a choledochal cyst

    Directory of Open Access Journals (Sweden)

    Nemade Bhushan

    2007-01-01

    Full Text Available Embryonal rhabdomyosarcoma (ERMS of biliary tree is a rare type of mesenchymal neoplasm diagnosed at surgery or by preoperative liver biopsy. We present a one year eight months old child who mimicked a choledochal cyst and was eventually treated with surgery, chemotherapy with IRS IV protocol and adjuvant postoperative radiotherapy to surgical bed with 6 MV photons to a dose of 5040cGy in 28 fractions.

  13. Spitz Nevus on the Earlobe Mimicking Cutaneous Leishmaniasis

    Directory of Open Access Journals (Sweden)

    İbrahim Özmen

    2010-06-01

    Full Text Available Spitz nevus is a benign, usually acquired melanocytic tumor which is seen especially in children and adolescents. It usually appears as a pink or light-brown, smooth-surfaced, well-circumscribed and asymptomatic papulonodular lesion. A large group of dermatologic disorders should be considered in the differential diagnosis. Herein we present a case of Spitz nevus with a two month history of a nodular lesion on the earlobe which mimicks cutaneous leishmaniasis clinically.

  14. Mimicking biological functionality with polymers for biomedical applications

    Science.gov (United States)

    Green, Jordan J.; Elisseeff, Jennifer H.

    2016-12-01

    The vast opportunities for biomaterials design and functionality enabled by mimicking nature continue to stretch the limits of imagination. As both biological understanding and engineering capabilities develop, more sophisticated biomedical materials can be synthesized that have multifaceted chemical, biological and physical characteristics designed to achieve specific therapeutic goals. Mimicry is being used in the design of polymers for biomedical applications that are required locally in tissues, systemically throughout the body, and at the interface with tissues.

  15. Acutely calcified hematoma mimicking a displaced medial epicondyle fracture

    Directory of Open Access Journals (Sweden)

    Majed Addie

    2009-01-01

    Full Text Available We present an interesting and unusual case of an acutely calcified pin-site infection hematoma mimicking a displaced cartilaginous medial epicondyle, in a child with a Gartland type III fracture. The treatment of such pathology could be confusing and may interfere with the correct clinical decision-making process. To our knowledge, this is the first presentation of such a case.

  16. Osteolytic nasal polyp of the maxillary sinus mimicking malignancy

    Directory of Open Access Journals (Sweden)

    Arvind Karikal

    2014-01-01

    Full Text Available We present an osteolytic nasal polyp of the maxillary sinus with clinical features and radiographic features mimicking that of a malignancy. Maxillary sinusitis being a common inflammatory condition progressed to cause destruction of the maxillary bone and spread into the facial soft tissue, which is quite a rare occurrence. We have discussed in detail the clinical, radiological, histopathology and management of this uncommon presentation of a common case.

  17. Juvenile Myelomonocytic Leukemia in a Premature Neonate Mimicking Neonatal Sepsis

    Directory of Open Access Journals (Sweden)

    Ming-Luen Lee

    2016-04-01

    Full Text Available Juvenile myelomonocytic leukemia (JMML is a rare hematologic malignancy in children. Its presentations include anemia, thrombocytopenia, monocytosis, skin rash, marked hepatomegaly, and/or splenomegaly. Fever and respiratory involvement are common. Here, we report a case of a premature neonate with initial symptoms of respiratory distress. She gradually developed clinical manifestations of JMML that mimicked neonatal sepsis. Three weeks after birth, JMML was diagnosed. This is the first reported case of JMML presenting in a premature infant in Taiwan.

  18. A Case of Hidroacanthoma Simplex Mimicking Bowen s Disease

    Directory of Open Access Journals (Sweden)

    Pinar Ozuguz

    2013-10-01

    Full Text Available Hidroacanthoma simplex is a rare benign tumor that originates from eccrine sweet gland ducts. The lesions are characterized by slowly-growing, flat or slightly elevated, skin-colored, brown or erythematous, verrucous papules or plaques. Clinically, plaques may resemble seborrheic keratosis, basal cell carcinoma and Bowen%u2019s disease. Here, we present a case of atypically localized hidroacanthoma simplex mimicking Bowen%u2019s disease.

  19. A case of gallbladder mass: Malakoplakia (The tumor mimicker

    Directory of Open Access Journals (Sweden)

    Kanwaljeet Singh

    2017-01-01

    Full Text Available Diagnosis of malakoplakia presenting as gall bladder mass is a diagnostic dilemma faced by pathologists, radiologists, and surgeons. Malakoplakia is a rare inflammatory disorder and tumor mimicker usually occurring in the urinary tract, may occasionally be found in gall bladder. Here, we present a rare case, presenting as gall bladder mass in a known case of gallstone disease, clinically suspected as carcinoma and later turned out to be malakoplakia in gall bladder.

  20. Tuberculosis of the skull mimicking a bony tumor

    OpenAIRE

    2016-01-01

    We present a rare case of calvarial tuberculosis mimicking a solitary bone tumor, which was surgically removed. A 52-year-old female presented with a right forehead swelling, which gradually enlarged over the course of 2 years, with no symptoms or raised intracranial pressure or neurological deficits. Plain and contrast-enhanced brain computed tomography scans were done, revealing a punched-out lesion of the right frontal bone, with a nonenhancing lytic mass. With an initial diagnosis of an i...

  1. A Q fever case mimicking crimean-congo haemorrhagic fever

    Directory of Open Access Journals (Sweden)

    O Karabay

    2011-01-01

    Full Text Available Coxiella burnetii is the bacterium that causes Q fever. Human infection is mainly transmitted from cattle, goats and sheep. The disease is usually self-limited. Pneumonia and hepatitis are the most common clinical manifestations. In this study, we present a case of Q fever from the western part of Turkey mimicking Crimean-Congo haemorrhagic fever (CCHF in terms of clinical and laboratory findings.

  2. Sciatic Hernia Mimicking Perianal Abscess in a Cirrhotic Patient

    Directory of Open Access Journals (Sweden)

    Wellington Andraus

    2012-01-01

    Full Text Available Abdominal hernias are very frequent in cirrhotic patients with ascites. The hernias usually present as umbilical, inguinal, incisional, or femoral. However, these patients can also develop uncommon hernias such as pelvic hernias because of pelvic floor weakness and high abdominal pressure due to ascites. We present the first case of a cirrhotic patient with ascites that developed a giant sciatic hernia mimicking a perianal abscess.

  3. Relationship between calcifying tendinitis and subacromial impingement: a prospective radiography and magnetic resonance imaging study.

    Science.gov (United States)

    Loew, M; Sabo, D; Wehrle, M; Mau, H

    1996-01-01

    In a prospective study radiographs and magnetic resonance images of 75 patients with calcifying tendinitis of the rotator cuff were analyzed. The aim was to evaluate any relation between calcifying tendinitis and subacromial impingement. A total of 83% of the calcifications were located in the supraspinatus or the adjoining part of the subscapularis tendon. On T1-weighted images they could be demonstrated with high accuracy as areas of decreased signal intensity. A magnetic resonance imaging categorization of the calcium deposits was carried out by means of a differentiation of form, outline, and density. A partial rotator cuff tear was found in one shoulder; in 11% variable aspects of degenerative alteration of the affected tendon were seen. By analysis of the radiographic outlet view 16% of the cases had a type III acromion. In conclusion, little correlation exists between calcifying tendinitis and additional findings associated with subacromial impingement.

  4. Experimental investigation of impingement heat transfer from a round rib-roughened surface

    Science.gov (United States)

    Isman, Mustafa Kemal; Can, Muhiddin

    2017-04-01

    An experimental investigation on impingement heat transfer from a rib-roughened surface is performed. Single, double, and triple rib configurations are tested. The rib is also located at three different positions for a single rib case. The Reynolds number is varied from 10,000 to 50,000 whereas the dimensionless jet-to-surface distance (z/D) is kept constant as 8. Results show that, the Nusselt number decreases just before a rib. After the rib, however, the Nusselt number decreases by a larger amount. Since ribs cause a reincreasing in the Nusselt number after the stagnation point and since the stagnation point Nusselt number is not affected by ribs, they can be used to enhance heat transfer especially for spot cooling applications. It is also obtained that using ribs is more useful for low speed impinging jets, when heat transfer from the whole surface is considered.

  5. LARGE-SCALE VORTICAL STRUCTURES PRODUCED BY AN IMPINGING DENSITY JET IN SHALLOW CROSSFLOW

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The large-scale vortical structures produced by an impinging density jet in shallow crossflow were numerically investigated in detail using RNG turbulence model.The scales, formation mechanism and evolution feature of the upstream wall vortex in relation to stagnation point and the Scarf vortex in near field were analyzed. The computed characteristic scales of the upstream vortex show distinguished three-dimensionality and vary with the velocity ratio and the water depth. The Scarf vortex in the near field plays an important role in the lateral concentration distributions of the impinging jet in crossflow. When the velocity ratio is relatively small, there exists a distinct lateral high concentration aggregation zone at the lateral edge between the bottom layer wall jet and the ambient crossflow, which is dominated by the Scarf vortex in the near field.

  6. Water Droplet Impingement on Simulated Glaze, Mixed, and Rime Ice Accretions

    Science.gov (United States)

    Papadakis, Michael; Rachman, Arief; Wong, See-Cheuk; Yeong, Hsiung-Wei; Hung, Kuohsing E.; Vu, Giao T.; Bidwell, Colin S.

    2007-01-01

    Water droplet impingement data were obtained at the NASA Glenn Icing Research Tunnel (IRT) for a 36-in. chord NACA 23012 airfoil with and without simulated ice using a dye-tracer method. The simulated ice shapes were defined with the NASA Glenn LEWICE 2.2 ice accretion program and including one rime, four mixed and five glaze ice shapes. The impingement experiments were performed with spray clouds having median volumetric diameters of 20, 52, 111, 154, and 236 micron. Comparisons to the experimental data were generated which showed good agreement for the rime and mixed shapes at lower drop sizes. For larger drops sizes LEWICE 2.2 over predicted the collection efficiencies due to droplet splashing effects which were not modeled in the program. Also for the more complex glaze ice shapes interpolation errors resulted in the over prediction of collection efficiencies in cove or shadow regions of ice shapes.

  7. Standard test method for conducting erosion tests by solid particle impingement using gas jets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This test method covers the determination of material loss by gas-entrained solid particle impingement erosion with jetnozzle type erosion equipment. This test method may be used in the laboratory to measure the solid particle erosion of different materials and has been used as a screening test for ranking solid particle erosion rates of materials in simulated service environments (1,2 ). Actual erosion service involves particle sizes, velocities, attack angles, environments, and so forth, that will vary over a wide range (3-5). Hence, any single laboratory test may not be sufficient to evaluate expected service performance. This test method describes one well characterized procedure for solid particle impingement erosion measurement for which interlaboratory test results are available. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determi...

  8. Numerical simulation on submerged gas jet scouring pit morphology in impingement water bath dust removers

    Institute of Scientific and Technical Information of China (English)

    GAO Huijie; WU Xuan; ZHAO Yuxiang; WU Wenfei; LI Baowei

    2014-01-01

    The VOF interface tracking method was adopted to simulate the two-dimensional submerged gas jet scouring pit morphology in an impingement water bath dust remover.The interaction of gas/liquid two-phase was obtained by force balance and momentum exchange.On the self-designed impingement water bath dust remover test bench,the submerged gas jet flushing with different gas velocities was simulated. The results show that,the gas inlet velocity is one of the main factors affecting the submerged gas jet scou-ring pit characteristics.The unique nature of gas/liquid two-phase determines their unique way of move-ment,thus affects the morphological character of the scouring pit in the expansion lag phase.Within the study range,the characteristic radius and impact depth of the scouring pit increases with the gas velocity, and so are their growth rates.

  9. Survey of fish impingement at power plants in the United States. Volume I. The Great Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Rajendra K.; Freeman, III, Richard F.

    1977-03-01

    Impingement of fish at cooling-water intakes of 20 power plants located on the Great Lakes has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV.

  10. Survey of fish impingement at power plants in the United States. Volume II. Inland waters

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, III, Richard F.; Sharma, Rajendra K.

    1977-03-01

    Impingement of fish at cooling-water intakes of 33 power plants located on inland waters other than the Great Lakes has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV.

  11. On the slip number choice in computations of liquid droplet impinging on a hydrophilic surface

    CERN Document Server

    Ganesan, Sashikumaar

    2015-01-01

    A mesh-dependent relation for the slip number in the Navier-slip with friction boundary condition for computations of impinging droplets is proposed. The relation is obtained as a function of the Reynolds number, the Weber number and the mesh size. The proposed relation is validated for several test cases by comparing the numerically obtained wetting diameter with the experimental results. Further, the computationally obtained maximum wetting diameter using the proposed slip relation is verified with the theoretical predictions. The relative error between the computationally obtained maximum wetting diameter and the theoretical predictions is less than 10\\% for impinging droplet on a hydrophilic surface, and the error increases in the case of hydrophobic surface.

  12. Droplet impinging behavior on surfaces: Part II - Water on aluminium and cast iron surfaces

    Science.gov (United States)

    Sangavi, S.; Balaji, S.; Mithran, N.; Venkatesan, M.

    2016-09-01

    Droplet cooling of metal surfaces is an important area of research in industrial applications such as material quenching, nozzle spraying, etc. Fluids (water) act as an excellent agent in heat transfer to remove excess heat in various processes by convection and conduction. Such cooling process varies the material properties. The bubbles formed during droplet impinging on the surface act as heat sink and causes variation of height and spreading radius of the droplet with increase in temperature. In the present work, an experimental study of the droplet impinging behavior on Aluminium and Cast iron surfaces is reported. The water droplets are made to fall on the surface of the specimens from a specific height, which also influences the spreading radius. The effect of temperature on droplet height and droplet spreading radius is detailed.

  13. AN EXPERIMENTAL OBSERVATION OF A SOLITARY WAVE IMPINGEMENT, RUN-UP AND OVERTOPPING ON A SEAWALL

    Institute of Scientific and Technical Information of China (English)

    LIN Ting-Chieh; HWANG Kao-Shu; HSIAO Shih-Chun; YANG Ray-Yeng

    2012-01-01

    A sequence of laboratory experiments using solitary waves was performed to model the effect of leading form of three types of tsunamis (a bore,an impinging wave and an overtopping wave) on a seawall on a sloping beach.The wave evolution process,impinging pressure along the seawall surface,total overtopping discharge behind the seawall and the maximum run-up height on the rear slope were measured and compared.Laboratory data were employed to re-examine relevant empirical formulae in the literature.The effect of the presence of the seawall in reducing maximum run-up height using the present setup was briefly discussed.The present data can be used for calibrating numerical and mathematical models.

  14. Dengue fever mimicking acute appendicitis: A case report.

    Science.gov (United States)

    McFarlane, M E C; Plummer, J M; Leake, P A; Powell, L; Chand, V; Chung, S; Tulloch, K

    2013-01-01

    Dengue fever is an acute viral disease, which usually presents as a mild febrile illness. Patients with severe disease present with dengue haemorrhagic fever or dengue toxic shock syndrome. Rarely, it presents with abdominal symptoms mimicking acute appendicitis. We present a case of a male patient presenting with right iliac fossa pain and suspected acute appendicitis that was later diagnosed with dengue fever following a negative appendicectomy. A 13-year old male patient presented with fever, localized right-sided abdominal pain and vomiting. Abdominal ultrasound was not helpful and appendicectomy was performed due to worsening abdominal signs and an elevated temperature. A normal appendix with enlarged mesenteric nodes was found at surgery. Complete blood count showed thrombocytopenia with leucopenia. Dengue fever was now suspected and confirmed by IgM enzyme-linked immunosorbent assay against dengue virus. This unusual presentation of dengue fever mimicking acute appendicitis should be suspected during viral outbreaks and in patients with atypical symptoms and cytopenias on blood evaluation in order to prevent unnecessary surgery. This case highlights the occurrence of abdominal symptoms and complications that may accompany dengue fever. Early recognition of dengue fever mimicking acute appendicitis will avoid non-therapeutic operation and the diagnosis may be aided by blood investigations indicating a leucopenia, which is uncommon in patients with suppurative acute appendicitis. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Heparin-Mimicking Polymers: Synthesis and Biological Applications.

    Science.gov (United States)

    Paluck, Samantha J; Nguyen, Thi H; Maynard, Heather D

    2016-11-14

    Heparin is a naturally occurring, highly sulfated polysaccharide that plays a critical role in a range of different biological processes. Therapeutically, it is mostly commonly used as an injectable solution as an anticoagulant for a variety of indications, although it has also been employed in other forms such as coatings on various biomedical devices. Due to the diverse functions of this polysaccharide in the body, including anticoagulation, tissue regeneration, anti-inflammation, and protein stabilization, and drawbacks of its use, analogous heparin-mimicking materials are also widely studied for therapeutic applications. This review focuses on one type of these materials, namely, synthetic heparin-mimicking polymers. Utilization of these polymers provides significant benefits compared to heparin, including enhancing therapeutic efficacy and reducing side effects as a result of fine-tuning heparin-binding motifs and other molecular characteristics. The major types of the various polymers are summarized, as well as their applications. Because development of a broader range of heparin-mimicking materials would further expand the impact of these polymers in the treatment of various diseases, future directions are also discussed.

  16. Heparin-Mimicking Polymers: Synthesis and Biological Applications

    Science.gov (United States)

    2016-01-01

    Heparin is a naturally occurring, highly sulfated polysaccharide that plays a critical role in a range of different biological processes. Therapeutically, it is mostly commonly used as an injectable solution as an anticoagulant for a variety of indications, although it has also been employed in other forms such as coatings on various biomedical devices. Due to the diverse functions of this polysaccharide in the body, including anticoagulation, tissue regeneration, anti-inflammation, and protein stabilization, and drawbacks of its use, analogous heparin-mimicking materials are also widely studied for therapeutic applications. This review focuses on one type of these materials, namely, synthetic heparin-mimicking polymers. Utilization of these polymers provides significant benefits compared to heparin, including enhancing therapeutic efficacy and reducing side effects as a result of fine-tuning heparin-binding motifs and other molecular characteristics. The major types of the various polymers are summarized, as well as their applications. Because development of a broader range of heparin-mimicking materials would further expand the impact of these polymers in the treatment of various diseases, future directions are also discussed. PMID:27739666

  17. Cryogenic Impinging Jets Subjected to High Frequency Transverse Acoustic Forcing in a High Pressure Environment

    Science.gov (United States)

    2016-07-27

    Forcing in a High Pressure Environment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Mario Roa, S. Alex Schumaker...disclose the work. PA Clearance Number: 16308 Clearance Date: 6/17/2016 13. SUPPLEMENTARY NOTES For presentation at AIAA Propulsion and Energy; Salt...the coupling between the impact waves created by impinging jets and high frequency acoustic pressure perturbations. High speed, backlit imaging was

  18. An experimental method for measuring droplet impingement efficiency on two- and three-dimensional bodies

    Science.gov (United States)

    Papadakis, M.; Zumwalt, G. W.; Kim, J. J.; Elangovan, R.; Freund, G. A., Jr.

    1986-01-01

    An efficient and accurate method is described for extracting water droplet impingement efficiency data from dye impregnated blotter paper samples obtained by employing a dye-tracer technique in wind tunnel spray tests. The method is based on laser reflectance spectroscopy. A brief description of the test method, instrumentation, and data reduction system is also presented. Preliminary test results and analyses are included for a cylinder and a 65(2)015 airfoil.

  19. Zero Secular Torque on Asteroids from Impinging Solar Photons in the YORP Effect: A Simple Proof

    Science.gov (United States)

    Rubincam, David Perry; Paddack, Stephen J.

    2010-01-01

    YORP torques, where "YORP" stands for "Yarokovsky-O'Keefe-Radzievskii-Paddack." arise mainly from sun light reflected off a Solar System object and the infrared radiation emi tted by it. We show here, through the most elementary demonstration that we Can devise, that secular torques from impinging solar photons are generally negligible and thus cause little secular evolution of an asteroid's obliquity or spin rate.

  20. The Role of Femoroacetabular Impingement in Core Muscle Injury/Athletic Pubalgia: Diagnosis and Management

    OpenAIRE

    Thomas eEllis; David eRenton; David eStrosberg

    2016-01-01

    Chronic groin pain in athletes represents a major diagnostic and therapeutic challenge in sports medicine. Two recognized causes of inguinal pain in the young adult athlete are core muscle injury/athletic pubalgia (CMI/AP) and femoroacetabular impingement (FAI). CMI/AP and FAI were previously considered to be two distinct entities, however recent studies have suggested both entities to frequently coincide in the athlete with groin pain. This article briefly discusses the role of femoroaceta...

  1. Assessment of analytical techniques for predicting solid propellant exhaust plumes and plume impingement environments

    Science.gov (United States)

    Tevepaugh, J. A.; Smith, S. D.; Penny, M. M.

    1977-01-01

    An analysis of experimental nozzle, exhaust plume, and exhaust plume impingement data is presented. The data were obtained for subscale solid propellant motors with propellant Al loadings of 2, 10 and 15% exhausting to simulated altitudes of 50,000, 100,000 and 112,000 ft. Analytical predictions were made using a fully coupled two-phase method of characteristics numerical solution and a technique for defining thermal and pressure environments experienced by bodies immersed in two-phase exhaust plumes.

  2. Numerical simulation on the intensification of mass transfer of wastewater treatment by advanced oxidation coupling impinging stream%高级氧化耦合撞击流技术强化废水降解过程的数值模拟

    Institute of Scientific and Technical Information of China (English)

    黄健光; 钟理

    2011-01-01

    为了探讨应用撞击流技术强化废水高级氧化降解过程,采用控制容积数值分析法通过FLUENT软件分别模拟了气相和液相单相撞击流的流场,为模拟气液两相流的撞击流流场,建立了k1-ε1-kb-εb双流体数学模型,并模拟了气液双流体撞击过程.模拟结果表明,撞击过程形成强烈的湍动,为强化传递提供很好的条件.气液撞击过程中强烈的相互渗透作用表明,应用撞击流强化废水高级氧化降解过程,是有效而且是可行的.%To study the effect of impinging stream technology on the degradation of organic pollutants in wastewater by advanced oxidation,numerical simulations were performed to study the flow characteristics of gas and water impinging streams through the FLUENT software by controlled volume numerical analysis. A two-phase-fluid mathematic model of k1-ε1-kb-εb method was also established to further study the flow characteristics of a two-phase-fluid impinging stream. The simulating results showed that strong turbulent flow is formed during the impinging process which provides excellent conditions for mass transfer intensification. The strong mutual-permeability of gas and water also indicated that the impinging stream technology is effective and viable to intensify the mass transfer process of wastewater treatment by advanced oxidation.

  3. The Effect of Reaction Control System Thruster Plume Impingement on Orion Service Module Solar Array Power Production

    Science.gov (United States)

    Bury, Kristen M.; Kerslake, Thomas W.

    2008-01-01

    NASA's new Orion Crew Exploration Vehicle has geometry that orients the reaction control system (RCS) thrusters such that they can impinge upon the surface of Orion's solar array wings (SAW). Plume impingement can cause Paschen discharge, chemical contamination, thermal loading, erosion, and force loading on the SAW surface, especially when the SAWs are in a worst-case orientation (pointed 45 towards the aft end of the vehicle). Preliminary plume impingement assessment methods were needed to determine whether in-depth, timeconsuming calculations were required to assess power loss. Simple methods for assessing power loss as a result of these anomalies were developed to determine whether plume impingement induced power losses were below the assumed contamination loss budget of 2 percent. This paper details the methods that were developed and applies them to Orion's worst-case orientation.

  4. Heat transfer in the flow of a cold, two-dimensional vertical liquid jet against a hot, horizontal plate

    CERN Document Server

    Shu, Jian-Jun

    2014-01-01

    A cold, thin film of liquid impinging on an isothermal hot, horizontal surface has been investigated. An approximate solution for the velocity and temperature distributions in the flow along the horizontal surface is developed, which exploits the hydrodynamic similarity solution for thin film flow. The approximate solution may provide a valuable basis for assessing flow and heat transfer in more complex settings.

  5. [Hip arthroscopy in males younger than 40 with femoroacetabular impingement: short-term outcomes].

    Science.gov (United States)

    Más Martínez, J; Morales-Santías, M; Bustamante Suarez Suarez de Puga, D; Sanz-Reig, J

    2014-01-01

    Femoroacetabular impingement is probably the most common mechanism that leads to the development of early cartilage and labral damage in the non-dysplastic hip. The objective was to evaluate the outcomes of hip arthroscopy as a treatment for femoroacetabular impingement in patients with high level of function. A prospective study was performed on 41 patients younger than 40 years old undergoing hip arthroscopy for femoroacetabular impingement. Modified Harris Hip Score and HOS and IHOT questionnaires were used for clinical assessment. Radiological evaluation was made for joint space and alpha angle. The mean age of patients was 32.7 years. Labrum injury was detected in 78%, and acetabular cartilage injury in 56% of cases. The average follow-up was 31.3 months. There was a significantly improvement in the mean score in the clinical questionnaires. Radiologically there was no change in the mean joint space, with significantly reduction to normal values of the alpha angle. All patients returned to sports at their pre-injury level of function. Hip arthroscopy resulted in improvement in hip functional outcomes with correction of the underlying osseous deformity and treatment of the associated labral and cartilage pathology, with the return of patients to their pre-injury sports. Further follow-up is essential to confirm the stability of the clinical and radiological outcomes. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

  6. Heat transfer of impinging jet-array over convex-dimpled surface

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shyy Woei [Thermal Fluids Laboratory, National Kaohsiung Marine University, No. 142, Haijhuan Road, Nanzih District, Kaohsiung City 81143, Taiwan (China); Jan, Yih Jena; Chang, Shuen Fei [Department of Marine Engineering, National Kaohsiung Marine University, No. 142, Haijhuan Road, Nanzih District, Kaohsiung City 81143, Taiwan (China)

    2006-08-15

    A detailed heat transfer measurement over a convex-dimpled surface of impinging jet-array with three eccentricities (E/H) between jet-centre and dimple-centre is performed. These surface dimples considerably modify heat transfers from smooth-walled scenarios due to different impinging topologies for jet array with modified inter-jet reactions. Heat transfer variations caused by adjusting jet Reynolds number (Re) and separation distance (S/D{sub j}) over the ranges of 5000=impinging surface. (author)

  7. [The relationship between quality of life and functional status measurements in shoulder impingement syndrome].

    Science.gov (United States)

    Ozcan, Ayşe; Tulum, Zeliha; Bacakoğlu, A Kadir

    2003-01-01

    We compared three questionnaires that are used in the assessment of function and quality of life of patients with shoulder impingement syndrome. The study included 54 patients (42 females, 12 males; mean age 54 years) with a diagnosis of stage I or II shoulder impingement syndrome. All the patients were administered a standard questionnaire regarding their general health status (Short-Form 36 / SF-36). Functional evaluations were made using the UCLA (University of California at Los Angeles) and Constant scoring systems. The results of the UCLA and Constant scores were compared with those of SF-36 with the use of Pearson correlation analysis. A strong correlation was found between the UCLA and Constant scores (p=0.006). SF-36 parameters of physical function, vitality, and social function showed a strong correlation with the UCLA scores (p<0.005), whereas parameters of general health and role emotional exhibited a moderate correlation (p<0.05). When compared with the Constant scores, SF-36 showed a strong correlation only in parameters of pain and general health (p<0.005). The parameter of role emotional was negatively correlated with the Constant scores. Demonstration of correlations between some parameters of SF-36 and the UCLA and Constant scoring systems suggests that SF-36 can be used to assess quality of life of patients with shoulder impingement syndrome.

  8. Spray-Wall Impingement of Diesel-CNG Dual Fuel Jet using Schlieren Imaging Technique

    Directory of Open Access Journals (Sweden)

    Ismael Mhadi Abaker

    2014-07-01

    Full Text Available Natural gas is a low cost fuel with high availability in nature. However, it cannot be used by itself in conventional diesel engines due to its low flame speed and high ignition temperature. The addition of a secondary fuel to enhance the mixture formation and combustion process facilitate its wider use as an alternative fuel. An experimental study was performed to investigate the diesel-CNG dual fuel jet-wall impingement. A constant volume optical chamber was designed to facilitate maximum optical access for the study of the jet-wall impingement at different injection pressures, temperatures and injector-wall distances. The bottom plate of the test rig was made of aluminum (piston material and it was heated up to 500 K at ambient pressure. An injector driver was used to control the single-hole nozzle diesel injector combined with a natural gas injector. The injection timing of both injectors was synchronized with a camera trigger. The jet-wall impingement of diesel and diesel-CNG dual fuel jets was recorded with a high speed camera using Schlieren imaging technique and associated image processing software. The measurements of the jet radial penetration were higher in diesel-CNG dual fuel while the jet height travel along were higher in the case of diesel single fuel.

  9. NUMERICAL SIMULATION OF THE FORMATION OF NANOPARTICLES IN AN IMPINGING TWIN-JET

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Large Eddy Simulation (LES) method has been used to solve the fluid momentum equations coupled with a convection-diffusion equation to study the formation of pollutant nanoparticles in a vehicular exhaust with impinging twin-jet. The functions of the space (S) between the two jets and the distance (H) from the exit of nozzle to the impingement plane are evaluated according to the distributions of pollutant nanoparticles. The results show that the nucleation produces a large number of nanoparticles, and gas-to-nanoparticle conversion mostly takes place in the interface region of the two jets, the circumambience of the jets, and region near the plane. The maximal particle size and maximal number concentration produced by both nucleation and coagulation appear around the region of free jet and the region near the plane, respectively. The significant differences for various spaces between the two jets are the number concentration and size distributions in the interface region of the two jets. For the case with larger space, more nanoparticles are produced by nucleation and coagulation. The more the distance from the exit of nozzle to the impingement plane, the lower is the number concentration and the fewer the particles distribute near the plane. Increasing the distance from nozzle to plane is beneficial to the reduction of nanoparticle formation.

  10. Surgical dislocation of the hip in patients with femoroacetabular impingement: Surgical techniques and our experience

    Directory of Open Access Journals (Sweden)

    Mladenović Marko

    2015-01-01

    Full Text Available Background/Aim. Arthrosis of the hip is the most common cause of a hip joint disorders. The aim of this study was to present our experience in the application of a safe surgical dislocation of the hip in patients with minor morphological changes in the hip joint, which, through the mechanism of femoroacetabular impingement, cause damage to the acetabular labrum and adjacent cartilage as an early sign of the hip arthrosis. Methods. We have operated 51 patients with different morphological bone changes in the hip area and resultant soft tissue damage of the acetabular labrum and its adjacent cartilage. Surgical technique that we applied in this group of patients, was adapted to our needs and capabilities and it was minimaly modified compared to the original procedure. Results. The surgical technique presented in this paper, proved to be a good method of treatment of bone and soft tissue pathomorphological changes of the hip in patients with femoroacetabular impingement. We had no cases with avascular necrosis of the femoral head, and two patients had nonunion of the greater trochanter, 9 patients developed paraarticular ossification, without subjective symptoms, while 3 patients suffered from postoperative pain in the groin during more energetic physical activities. Conclusion. Utilization of our partly modified surgical technique of controlled and safe dislocation of the hip can solve all the bone and soft tissue problems in patients with femoroacetibular impingement to stop already developed osteoarthritis of the hip or to prevent mild form of it.

  11. Femur-mounted navigation system for the arthroscopic treatment of femoroacetabular impingement

    Science.gov (United States)

    Park, S. H.; Hwang, D. S.; Yoon, Y. S.

    2013-07-01

    Femoroacetabular impingement stems from an abnormal shape of the acetabulum and proximal femur. It is treated by resection of damaged soft tissue and by the shaping of bone to resemble normal features. The arthroscopic treatment of femoroacetabular impingement has many advantages, including minimal incisions, rapid recovery, and less pain. However, in some cases, revision is needed owing to the insufficient resection of damaged bone from a misreading of the surgical site. The limited view of arthroscopy is the major reason for the complications. In this research, a navigation method for the arthroscopic treatment of femoroacetabular impingement is developed. The proposed navigation system consists of femur attachable measurement device and user interface. The bone mounted measurement devices measure points on head-neck junction for registration and position of surgical instrument. User interface shows the three-dimensional model of patient's femur and surgical instrument position that is tracked by measurement device. Surgeon can know the three-dimensional anatomical structure of hip joint and surgical instrument position on surgical site using navigation system. Surface registration was used to obtain relation between patient's coordinate at the surgical site and coordinate of three-dimensional model of femur. In this research, we evaluated the proposed navigation system using plastic model bone. It is expected that the surgical tool tracking position accuracy will be less than 1 mm.

  12. Obturator nerve impingement as a severe late complication of bilateral triple pelvic osteotomy.

    Science.gov (United States)

    Tong, K; Hayashi, K

    2012-01-01

    A four-year-old female spayed Labrador Retriever, which had undergone bilateral triple pelvic osteotomy (TPO) at the age of eight months, was presented with severe progressive shifting pelvic limb lameness for a duration of three months prior to presentation. The dog had multiple episodes of showing signs of excruciating pain, as well as an inability to rise or ambulate, inappetance, and lethargy. Orthopaedic examination revealed severe bilateral pelvic limb muscular atrophy, and signs of severe pain on abduction of the pelvic limbs, on rectal palpation ventrally, and on palpation of the region of the iliopsoas and pectineus muscles bilaterally. Surgery was indicated to explore the region and to release the pectineus and iliopsoas muscles. During surgery, callus tissue and the free section of pubic bone were found to be impinging on the obturator nerve at the previous TPO pubic osteotomy site bilaterally. On both sides, a 1 to 2 cm segment of pubis and fibrous callus tissue were excised and the obturator nerves were freed from the impingement. Immediately after the surgery, the patient's stance and gait were dramatically improved. The dog could maintain a much broader based stance and make longer strides with the pelvic limbs. At the two month follow-up examination, there were not any signs of lameness noted. Obturator nerve impingement can be a serious potential complication of TPO and may manifest clinically as marked pelvic limb lameness years after surgery.

  13. Fyzioterapeutická péče u pacienta s diagnózou impingement syndrom

    OpenAIRE

    2014-01-01

    This thesis deals with the issue of physiotherapeutical care of patients diagnosed with impingement syndrome of arteculatio humeri. Impingement syndrome means an oppression or distress in the area of arteculatio humeri. That signifies an oppression of tendon m. supraspinatus in the subacromial area.It is clinically demonstrated by pain and functional limitation of movement and is caused by an overload of rotator cuff and its oppression with traumatic changes in the area of subacromial area.Th...

  14. Kazuistika fyzioterapeutické péče o pacienta s diagnózou impingement syndrom

    OpenAIRE

    Vontorová, Simona

    2012-01-01

    Title: The case report of physiotherapy care of a patient with the diagnosis of impingement syndrom. The objective of this bachelor thesis is introduction of physiotherapy of upper limb girdle with impingement syndrom. The thesis is dividend in two main parts. In the first part is described the girdle of the upper limb in the view of anatomy, kinesiology and biomechanics. There are listed procedures for testing and treatment and point of view of physiotherapy and surgical treatment by arthros...

  15. Launch Environment Water Flow Simulations Using Smoothed Particle Hydrodynamics

    Science.gov (United States)

    Vu, Bruce T.; Berg, Jared J.; Harris, Michael F.; Crespo, Alejandro C.

    2015-01-01

    This paper describes the use of Smoothed Particle Hydrodynamics (SPH) to simulate the water flow from the rainbird nozzle system used in the sound suppression system during pad abort and nominal launch. The simulations help determine if water from rainbird nozzles will impinge on the rocket nozzles and other sensitive ground support elements.

  16. Investigation of extraction fraction in confined impinging jet reactors for tri-butyl-phosphate extracting butyric acid process☆

    Institute of Scientific and Technical Information of China (English)

    Zhengming Gao; Manting Zhao; Yun Yu; Zhipeng Li; Jing Han

    2016-01-01

    The extraction fraction E and overall volumetric mass transfer coefficient kLa of TBP extracting butyric acid pro-cess in confined impinging jet reactors (CIJR) with two jets were investigated. The main variables tested were the concentration of tri-butyl-phosphate (TBP) and butyric acid, the impinging velocity V, the impinging velocity ratio of two phases Vorg/Vaq, the nozzle inner diameter di and the distance L between the jet axes and the top wall of the impinging chamber. The results showed that E and kLa increase with an increase of the impinging ve-locity V, the concentration of TBP Corg, and the impinging velocity ratio Vorg/Vaq. However, E and kLa decrease with an increase of the inner diameter di from 1 to 2 mm, the concentration of butyric acid Caq from 0.5%(v/v) to 2%(v/v). The factor L ranging from 3 to 11 mm has a negligible effect on E and kLa. A correlation on these variables and kLa was proposed based on the experimental data. These results indicated good mass transfer performance of CIJR in the extraction operation.

  17. Analysis of Impingement between Patella Bone and Bearing Post in Cruciate-Substituting High-Flexion Total Knee Arthroplasty.

    Science.gov (United States)

    Chon, Jegyun; Lee, Bongju; Shin, Sangyeop; Jang, Gunil; Jeon, Taehyeon

    2016-06-01

    We investigated the causes of impingement between the patella bone and the bearing post during high flexion in cruciate-substituting total knee arthroplasty and proposed a treatment strategy. This prospective cohort study included 218 cases that had undergone cruciate-substituting total knee arthroplasty from February 2014 to January 2015; a single surgeon performed the operation using the same method without patellar resurfacing in all patients. In these patients, the occurrence of impingement was determined by performing more than 120° high knee flexion after inserting a bearing perioperatively. The incidence of impingement was significantly associated with bearing design, femoral implant size, patella bone length, and patella inferior pole angle (p patella bone. In the cruciate-substituting high-flexion total knee arthroplasty, impingement between the patella bone and bearing post was more common in patients with mobile bearing, small-size femoral component, and a long patella or a large inferior pole angle. In cases of intraoperative impingement between the patella bone and the bearing post, resection in the lower portion of the patella prevented impingement of the bearing with soft tissue or the patella by widening the space between the patella and the bearing post, which in turn prevented postoperative reduction in range of motion.

  18. Micrometer-sized water droplet impingement dynamics and evaporation on a flat dry surface.

    Science.gov (United States)

    Briones, Alejandro M; Ervin, Jamie S; Putnam, Shawn A; Byrd, Larry W; Gschwender, Lois

    2010-08-17

    A comprehensive numerical and experimental investigation on micrometer-sized water droplet impact dynamics and evaporation on an unheated, flat, dry surface is conducted from the standpoint of spray-cooling technology. The axisymmetric time-dependent governing equations of continuity, momentum, energy, and species are solved. Surface tension, wall adhesion effect, gravitational body force, contact line dynamics, and evaporation are accounted for in the governing equations. The explicit volume of fluid (VOF) model with dynamic meshing and variable-time stepping in serial and parallel processors is used to capture the time-dependent liquid-gas interface motion throughout the computational domain. The numerical model includes temperature- and species-dependent thermodynamic and transport properties. The contact line dynamics and the evaporation rate are predicted using Blake's and Schrage's molecular kinetic models, respectively. An extensive grid independence study was conducted. Droplet impingement and evaporation data are acquired with a standard dispensing/imaging system and high-speed photography. The numerical results are compared with measurements reported in the literature for millimeter-size droplets and with current microdroplet experiments in terms of instantaneous droplet shape and temporal spread (R/D(0) or R/R(E)), flatness ratio (H/D(0)), and height (H/H(E)) profiles, as well as temporal volume (inverted A) profile. The Weber numbers (We) for impinging droplets vary from 1.4 to 35.2 at nearly constant Ohnesorge number (Oh) of approximately 0.025-0.029. Both numerical and experimental results show that there is air bubble entrapment due to impingement. Numerical results indicate that Blake's formulation provides better results than the static (SCA) and dynamic contact angle (DCA) approach in terms of temporal evolution of R/D(0) and H/D(0) (especially at the initial stages of spreading) and equilibrium flatness ratio (H(E)/D(0)). Blake's contact line

  19. Psoas impingement causing labrum tear: a series from three tertiary hip arthroscopy centers.

    Science.gov (United States)

    Cascio, Brett M; King, David; Yen, Yi-Meng

    2013-01-01

    The term hip impingement is usually associated with psoas impingement after arthroplasty or femoroacetabular impingement (FAI). A recently, less commonly described mechanism of impingement and labrum pathology is the psoas tendon applying pressure to the acetabular labrum more medial to the typical FAI labrum lesion. Much is still unkown about the anatomy, pathology, and treatment of this entity. This paper describes the successful arthroscopic treatment of a series of patients with a recently recognized cause of hip pain in the young athletic population without significant bony pathology or coxa saltans. Awareness of this entity is important to allow appropriate treatment of the labrum and psoas tendon. Seven hundred hip arthroscopies by three surgeons at different centers were retrospectively reviewed. Athletes with labrum tears from the two to three o'clock position were evaluated for inclusion in the study. Patients with osteoarthritis, crossover sign, coxa profunda, CAM lesion, acute trauma, or coxa saltans were excluded. All authors were the primary surgeons and are fellowship-trained hip arthroscopists working in tertiary hip arthroscopy centers. Pre- and postoperative Harris Hip scores were obtained. Patients underwent diagnostic and therapeutic hip arthroscopy. The psoas tendon was released in all patients at the level of the capsule via a transcapsular approach. Labrum repairs were performed when deemed beneficial by the operative surgeon. Twenty-two patients (26 hips, 4 bilateral) were identified with a labrum tear apparently caused by psoas impingement and had no other significant hip abnormalities. All but one were female. Average age was 19 (12-25 years). Labral repair was performed in all but two patients. Average anchors used were 1.2 per hip. Pre- and postoperative Harris hip scores were obtained with a minimum follow-up of six months for 16 patients. Average Harris hip score improved from 70 preop to 94 postop. There were no significant

  20. Analysis of a Free Surface Film from a Controlled Liquid Impinging Jet over a Rotating Disk Including Conjugate Effects, with and without Evaporation

    Science.gov (United States)

    Sankaran, Subramanian (Technical Monitor); Rice, Jeremy; Faghri, Amir; Cetegen, Baki M.

    2005-01-01

    A detailed analysis of the liquid film characteristics and the accompanying heat transfer of a free surface controlled liquid impinging jet onto a rotating disk are presented. The computations were run on a two-dimensional axi-symmetric Eulerian mesh while the free surface was calculated with the volume of fluid method. Flow rates between 3 and 15 1pm with rotational speeds between 50 and 200 rpm are analyzed. The effects of inlet temperature on the film thickness and heat transfer are characterized as well as evaporative effects. The conjugate heating effect is modeled, and was found to effect the heat transfer results the most at both the inner and outer edges of the heated surface. The heat transfer was enhanced with both increasing flow rate and increasing rotational speeds. When evaporative effects were modeled, the evaporation was found to increase the heat transfer at the lower flow rates the most because of a fully developed thermal field that was achieved. The evaporative effects did not significantly enhance the heat transfer at the higher flow rates.