Four-jet impingement: Noise characteristics and simplified acoustic model

International Nuclear Information System (INIS)

Brehm, C.; Housman, J.A.; Kiris, C.C.; Barad, M.F.; Hutcheson, F.V.

2017-01-01

Highlights: • Large eddy simulation of unique four jet impingement configuration. • Characterization of flow features using POD, FFT, and wavelet decomposition. • Noise source identification utilizing causality method. • Development of simplified acoustic model utilizing equivalent source method. • Comparison with experimental data from BENS experiment. - Abstract: The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order weighted essentially non-oscillatory scheme. Although these types of impinging jet configurations have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition 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 vortical flow structures in the center of the four-jet impingement region. The causality method based on Lighthills 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 plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a simplified acoustic model of the four-jet impingement device by utilizing the equivalent source method. Finally, three linear acoustic four-jet impingement models of the four-jet impingement device are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data.

Fish impingement at Montecello Nuclear Plant

International Nuclear Information System (INIS)

Grotbeck, L.M.; Bechthold, J.L.

1975-01-01

To properly evaluate total impact of power generation facilities on aquatic systems, it is necessary to perform site specific fish impingement studies. Intake and screen approach velocities should not be averaged when considering potential screen impingement problems because of wide vertical and horizontal variation in velocity which tend to trap fish. It was estimated that 2,952 fish were impinged during 4 months of sampling with 90.9% of these comprised of black bullheads (Ictalurus melas) and black crappies (Pomoxis nigromaculatus). Distinct relationships can be found between number of impinging fish and river flow, percentage river diverted through the plant, water temperature, and the time of year. For the months of June, July, August, and September, approx 55% of all impingement occurs in June

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.

Investigation of impingement attack mechanism of copper alloy condenser tubes

Energy Technology Data Exchange (ETDEWEB)

Fukumura, Takuya; Nakajima, Nobuo; Arioka, Koji; Totsuka, Nobuo; Nakagawa, Tomokazu [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

In order to investigate generation and growth mechanisms of impingement attacks of sea water against copper alloy condenser tubes used in condensers of nuclear power plants, we took out condenser tubes from actual condensers, cut them into several pieces and carried out several material tests mainly for impinged spots. In addition water flow inside of a pit was analyzed. From the results of the investigation, it was found that all of impingement attacks were found in the marks left by sessile organisms and none were found in downstream of the marks as frequently proposed so far. At the pits generated inside the marks, iron coating was striped and zinc content was deficient in some cases. Combining these data and the result of flow analysis, we considered the following mechanism of the impingement attacks: sessile organisms clinging to the surface of the condenser tube and growth, occlusion of the tube, extinction and decomposition of sessile organisms, pollution corrosion under the organisms and cavity formation, occlusion removal by the cleaning, generation of impingement attacks by flow collision inside the cavity, growth of the impingement attacks. (author)

Performance of jet impingement in unglazed air collectors

Energy Technology Data Exchange (ETDEWEB)

Belusko, M.; Saman, W.; Bruno, F. [Institute for Sustainable Systems and Technologies, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095 (Australia)

2008-05-15

Jet impingement is effective at improving the heat transfer between air and a heated surface. Studies have shown that jet impingement can marginally improve the thermal efficiency of a glazed collector. However, little attention has been placed on applying jet impingement to an unglazed solar air collector. This paper presents a theoretical and experimental investigation identifying the performance characteristics of jet impingement. Overall, jet impingement was able to improve the thermal efficiency of the collector by 21%. An increase in the pressure loss was also measured but found to be small. The flow distribution of jets along the collector was the most significant factor in determining the efficiency. Increasing the hole spacing was found to improve the efficiency. (author)

Impinging jets - a short review on strategies for heat transfer enhancement

Science.gov (United States)

Nastase, Ilinca; Bode, Florin

2018-02-01

In industrial applications, heat and mass transfer can be considerably increased using impinging jets. A large number of flow phenomena will be generated by the impinging flow, such as: large scale structures, large curvature involving strong shear and normal stresses, stagnation in the wall boundary layers, heat transfer with the impinged wall, small scale turbulent mixing. All these phenomena are highly unsteady and even if nowadays a substantial number of studies in the literature are dedicated, the impinging jets are still not fully understood due to the highly unsteady nature and more over due to great difficulty of performing detailed numerical and experimental investigations.

Turbulent flow and heat transfer from a slot jet impinging on a moving plate

International Nuclear Information System (INIS)

Chattopadhyay, Himadri; Saha, Sujoy K.

2003-01-01

The flow field due to an impinging jet over a moving surface at a moderately high Reynolds number, emanating from a rectangular slot nozzle has been computed using the large eddy simulation technique. A dynamic subgrid-scale stress model has been used for the small scales of turbulence. The velocity of the impinging surface perpendicular to the jet velocity has been varied up to two times the jet velocity at the nozzle exit. Turbulence quantities such as kinetic energy, production rate of turbulent kinetic energy and the Reynolds stresses are calculated for different surface velocities. It has been observed that, while the turbulent kinetic energy increases with increasing velocity of the impinging surface, production rate of turbulence initially increases with increasing surface velocity and then comes down. By analyzing the components of turbulent production it was found that P 33 is the dominant term up to the surface velocity of one unit and when the surface velocity is two times the jet velocity at the nozzle exit, the major contribution to turbulence production comes from P 13 and partly from P 11 . Heat transfer from the plate initially increases with non-dimensional surface velocity up to 1.2 and then comes down

Investigation of vertical liquid film width upon impingement on flat plate

International Nuclear Information System (INIS)

Kim, Won J.; Son, Hyung M.; Suh, Kune Y.

2003-01-01

In the early, high pressure phase during a Large-Break Loss-Of-Coolant Accident (LBLOCA), the Emergency Core Cooling (ECC) water of the Direct Vessel Injection (DVI) system is supplied from the Safety Injection Tank (SIT). After the shortage of the SIT, the In-containment Refueling Water Storage Tank (IRWST) supplies water to the safety system. Velocity of the injection flow varies during the process from the initial value of over 10 m/s in the blowdown phase to 2∼3 m/s in the later phase of reflood. During the safety injection, such important phenomena are observed as impingement, bypass, entrainment and sweepout, and condensation. The impingement is referred to the case where the ECC water is injected to strike on the reactor inner vessel. Accordingly, the water generates a liquid film to form a ridge on the wall. The liquid film then flows down the wall due to gravity. This impingement is interrupted by the steam-water mixture bypass flow to the break. The bypass, in turn, is affected by the impingement. This study is intended to understand the impinged water flow behavior neglecting such secondary effects as the temperature-dependent thermodynamic properties and the reactor vessel curvature. An emphasis is put on interpreting the results of visual inspection to understand the underlying mechanism of rather complex turbulent flow in the downcomer

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

Numerical simulation of heat transfer and fluid flow of an impinging round jet of plasma into confined walls

International Nuclear Information System (INIS)

Ezato, Koichiro; Shimizu, Akihiko; Kunugi, Tomoaki.

1995-01-01

Numerical simulations are presented on the flow and heat transfer characteristics of an impinging round jet of argon plasma with atmospheric pressure. The target slab with finite thickness upon which plasma jet impinges is assumed to be as SiC which is a candidate material for plasma facing material of fusion reactor. The plasma jet is treated by use of a magnetohydrodynamics model that takes its two-temperature non-equilibrium state into account. The rear side of the target slab is assumed to be cooled by a gas-solid suspension impinging round jet. The result shows that the plasma is in non-equilibrium state in which the electron temperature is higher than the heavy particle in the outer region of plasma jet core and that the heat flux to the target slab is over 8 MW/m 2 in the region of the plasma jet core contacts. (author)

Effects of water chemistry on flow accelerated corrosion and liquid droplet impingement

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi; Lister, Derek H.

2009-01-01

Overlapping effects of flow dynamics and corrosion are important issues to determine reliability and lifetime of major structures and components in light water reactor plants. Flow accelerated corrosion (FAC) and liquid droplet impingement (LDI) are typical phenomena due to both interactions. In order to evaluation local wall thinning due to FAC and LDI, 6 step evaluation procedures have been proposed. (1) Flow pattern along the flow path was obtained with 1D computational flow dynamics (CFD) codes, (2) Corrosive conditions, e.g., oxygen concentration along the flow path were calculated with a hydrazine oxygen reaction code for FAC evaluation, while flow pattern of liquid droplets in high velocity steam and possibility of their collision to pipe inner surface were evaluated for LDI evaluation. (3) Mass transfer coefficient at the structure surface was calculated with 3D CFD codes for FAC evaluation, while frequency of oxide film rupture due to droplet collision was calculated for LDI evaluation. (4) High risk zones for FAC/LDI occurrence were evaluated by coupling major parameters, and then, (5) Wall thinning rates were calculated with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis at the identified high FAC/LDI risk zone. (author)

Femoroacetabular impingement

International Nuclear Information System (INIS)

Kassarjian, Ara; Brisson, Melanie; Palmer, William E.

2007-01-01

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

Supersonic impinging jet noise reduction using a hybrid control technique

Science.gov (United States)

Wiley, Alex; Kumar, Rajan

2015-07-01

Control of the highly resonant flowfield associated with supersonic impinging jet has been experimentally investigated. Measurements were made in the supersonic impinging jet facility at the Florida State University for a Mach 1.5 ideally expanded jet. Measurements included unsteady pressures on a surface plate near the nozzle exit, acoustics in the nearfield and beneath the impingement plane, and velocity field using particle image velocimetry. Both passive control using porous surface and active control with high momentum microjet injection are effective in reducing nearfield noise and flow unsteadiness over a range of geometrical parameters; however, the type of noise reduction achieved by the two techniques is different. The passive control reduces broadband noise whereas microjet injection attenuates high amplitude impinging tones. The hybrid control, a combination of two control methods, reduces both broadband and high amplitude impinging tones and surprisingly its effectiveness is more that the additive effect of the two control techniques. The flow field measurements show that with hybrid control the impinging jet is stabilized and the turbulence quantities such as streamwise turbulence intensity, transverse turbulence intensity and turbulent shear stress are significantly reduced.

Thermal-hydraulic performance of convective boiling jet array impingement

International Nuclear Information System (INIS)

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

2016-01-01

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 7 o C. 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. (paper)

Role of coherent structures in supersonic impinging jetsa)

Science.gov (United States)

Kumar, Rajan; Wiley, Alex; Venkatakrishnan, L.; Alvi, Farrukh

2013-07-01

This paper describes the results of a study examining the flow field and acoustic characteristics of a Mach 1.5 ideally expanded supersonic jet impinging on a flat surface and its control using steady microjets. Emphasis is placed on two conditions of nozzle to plate distances (h/d), of which one corresponds to where the microjet based active flow control is very effective in reducing flow unsteadiness and near-field acoustics and the other has minimal effectiveness. Measurements include unsteady pressures, nearfield acoustics using microphone and particle image velocimetry. The nearfield noise and unsteady pressure spectra at both h/d show discrete high amplitude impinging tones, which in one case (h/d = 4) are significantly reduced with control but in the other case (h/d = 4.5) remain unaffected. The particle image velocimetry measurements, both time-averaged and phase-averaged, were used to better understand the basic characteristics of the impinging jet flow field especially the role of coherent vortical structures in the noise generation and control. The results show that the flow field corresponding to the case of least control effectiveness comprise well defined, coherent, and symmetrical vortical structures and may require higher levels of microjet pressure supply for noise suppression when compared to the flow field more responsive to control (h/d = 4) which shows less organized, competing (symmetrical and helical) instabilities.

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

Energy Technology Data Exchange (ETDEWEB)

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.

Time resolved investigations on flow field and quasi wall shear stress of an impingement configuration with pulsating jets by means of high speed PIV and a surface hot wire array

International Nuclear Information System (INIS)

Janetzke, Timm; Nitsche, Wolfgang

2009-01-01

The effects of jet pulsation on flow field and quasi wall shear stress of an impingement configuration were investigated experimentally. The excitation Strouhal number and amplitude were varied as the most influential parameters. A line-array with three submerged air jets, and a confining plate were used. The flow field analysis by means of time resolved particle image velocimetry shows that the controlled excitation can considerably affect the near-field flow of an impinging jet array. These effects are visualized as organization of the coherent flow structures. Augmentation of the Kelvin-Helmholtz vortices in the jet shear layer depends on the Strouhal number and pulsation magnitude and can be associated with pairing of small scale vortices in the jet. A total maximum of vortex strength was observed when exciting with Sr = 0.82 and coincident high amplitudes. Time resolved interaction between impinging vortices and impingement plate boundary layer due to jet excitation was verified by using an array of 5 μm surface hot wires. Corresponding to the global flow field modification due to periodic jet pulsation, the impact of the vortex rings on the wall boundary layer is highly influenced by the above mentioned excitation parameters and reaches a maximum at Sr = 0.82.

Transverse jet-cavity interactions with the influence of an impinging shock

International Nuclear Information System (INIS)

Zare-Behtash, H.; Lo, K.H.; Kontis, K.; Ukai, T.; Obayashi, S.

2015-01-01

Highlights: • Experimental study of shock-jet-cavity in a supersonic freestream is conducted. • Shock impingement at the cavity leading edge lifts the shear layer, encouraging momentum transfer. • Shock impingement close to the jet location increases the number of smaller turbulent structures. - Abstract: For high-speed air breathing engines, fuel injection and subsequent mixing with air is paramount for combustion. The high freestream velocity poses a great challenge to efficient mixing both in macroscale and microscale. Utilising cavities downstream of fuel injection locations, as a means to hold the flow and stabilise the combustion, is one mechanism which has attracted much attention, requiring further research to study the unsteady flow features and interactions occurring within the cavity. In this study we combine the transverse jet injection upstream of a cavity with an impinging shock to see how this interaction influences the cavity flow, since impinging shocks have been shown to enhance mixing of transverse jets. Utilising qualitative and quantitative methods: schlieren, oilflow, PIV, and PSP the induced flowfield is analysed. The impinging shock lifts the shear layer over the cavity and combined with the instabilities generated by the transverse jet creates a highly complicated flowfield with numerous vertical structures. The interaction between the oblique shock and the jet leads to a relatively uniform velocity distribution within the cavity

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.

Jet array impingement flow distributions and heat transfer characteristics. Effects of initial crossflow and nonuniform array geometry. [gas turbine engine component cooling

Science.gov (United States)

Florschuetz, L. W.; Metzger, D. E.; Su, C. C.; Isoda, Y.; Tseng, H. H.

1982-01-01

Two-dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer surface. The configurations considered are intended to model those of interest in current and contemplated gas turbine airfoil midchord cooling applications. The effects of an initial crossflow which approaches the array through an upstream extension of the channel are considered. Flow distributions as well as heat transfer coefficients and adiabatic wall temperatures resolved to one streamwise hole spacing were measured as a function of the initial crossflow rate and temperature relative to the jet flow rate and temperature. Both Nusselt number profiles and dimensionless adiabatic wall temperature (effectiveness) profiles are presented and discussed. Special test results which show a significant reduction of jet orifice discharge coefficients owing to the effect of a confined crossflow are also presented, along with a flow distribution model which incorporates those effects. A nonuniform array flow distribution model is developed and validated.

Analysis of reactor material experiments investigating oxide fuel crust stability and heat transfer in jet impingement flow

International Nuclear Information System (INIS)

Sienicki, J.J.; Spencer, B.W.

1985-01-01

An analysis is presented of the crust stability and heat transfer behavior in the CSTI-1, CSTI-3, and CWTI-11 reactor material experiments in which a jet of molten oxide fuel at approx. 160 0 K above its freezing temperature was impinged normally upon stainless steel plates initially at 300 and 385 K. The major issue is the existence of nonexistence of a stable solidified layer of fuel, or crust, interstitial to the flowing hot fuel and the steel substrate, tending to insulate the steel from the hot molten fuel. A computer model was developed to predict the heatup of thermocouples imbedded immediately beneath the surface of the plate for both of the cases in which a stable crust is assumed to be either present or absent during the impingement phase. Comparison of the model calculations with the measured thermocouple temperatures indicates that a protective crust was present over nearly all of the plate surface area throughout the impingement process precluding major melting of the plate steel. However, the experiments also show evidence for very localized and isolated steel melting as revealed by localized and isolated pitting of the steel surface and the response of thermocouples located within the pitted region

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.

An analytical wall-function for recirculating and impinging turbulent heat transfer

International Nuclear Information System (INIS)

Suga, K.; Ishibashi, Y.; Kuwata, Y.

2013-01-01

Highlights: ► Improvement of the analytical wall-function is proposed. ► Strain parameter dependency is introduced to the prescribed eddy viscosity profile of the analytical wall-function. ► The model performance is evaluated in turbulent pipe, channel, back-step, abrupt expansion pipe and plane impinging flows. ► Generally improved heat transfer is obtained in all the test cases with the standard k-e model. -- Abstract: The performance of the analytical wall-function (AWF) of Craft et al. [Craft, T.J., Gerasimov, A.V., Iacovides, H., Launder, B.E., 2002, Progress in the generalisation of wall-function treatments. Int. J. Heat Fluid Flow 23, 148–160.] is improved for predicting turbulent heat transfer in recirculating and impinging flows. Since constant parameters of the eddy viscosity formula were used to derive the AWF, the prediction accuracy of the original AWF tends to deteriorate in complex flows where those parameters need changing according to the local turbulence. To overcome such shortcomings, the present study introduces a functional behaviour on the strain parameter into the coefficient of the eddy viscosity of the AWF. The presently modified version of the AWF is validated in turbulent heat transfer of pipe flows, channel flows, back-step flows, pipe flows with abrupt expansion and plane impinging slot jets. The results confirm that the present modification successfully improves the performance of the original AWF for all the flows and heat transfer tested

An experimental study of the supersonic, dual, coaxial jets impinging on an inclined flat plate

International Nuclear Information System (INIS)

Kim, Jung Bae; Lee, Jun Hee; Woo, Sun Hoon; Kim, Heuy Dong

2002-01-01

The impinging supersonic jets have been applied for rocket launching system, thrust control, gas turbine blade cooling, etc. Recently the supersonic, dual, coaxial jets are being extensively used in many diverse fields of industrial processes since they lead to more improved performance, compared with the conventional supersonic jets impinging on an object. In the present study, experimentation is carried out to investigate the supersonic, dual, coaxial jets impinging on an inclined flat plate. A convergent-divergent nozzle with a design Mach number of 2.0 and annular sonic nozzle are used to make the dual, coaxial jet flows. The angle of the impinging flat plate is varied from 30 .deg. to 60 .deg. and the distance between the dual coaxial nozzle and flat plate is also varied. Detailed pressures on the impinging plate are measured to analyze the flow fields, which are also visualized using Schlieren optical method

Properties of Supersonic Impinging Jets

Science.gov (United States)

Alvi, F. S.; Iyer, K. G.; Ladd, J.

1999-11-01

A detailed study examining the behavior of axisymmetric supersonic jets impinging on a ground plane is described. Our objective is to better understand the aeroacoustics governing this complex flowfield which commonly occurs in the vicinity of STOVL aircraft. Flow issuing through a Mach 1.5 C-D and a converging sonic nozzle is examined over a wide parametric range. For some cases a large diameter circular 'lift' plate, with an annular hole through which the jet is issued, is attached at the nozzle exit to simulate a generic airframe. The impinging jet flowfield was examined using Particle Image Velocimetry (PIV), which provides the velocity field for the entire region and shadowgraph visualization techniques. Near-field acoustic, as well as, mean and unsteady pressure measurements on the ground and lift plate surfaces were also obtained. The velocity field data, together with the surface flow measurements have resulted in a much better understanding of this flow from a fundamental standpoint while also identifying critical regions of interest for practical applications. Some of these findings include the presence of a stagnation bubble with recirculating flow; a very high speed (transonic/supersonic) radial wall jet; presence of large, spatially coherent turbulent structures in the primary jet and wall jet and high unsteady loads on the ground plane and lift plates. The results of a companion CFD investigation and its comparison to the experimental data will also be presented. Very good agreement has been found between the computational and experimental results thus providing confidence in the development of computational tools for the study of such flows.

Plume Impingement to the Lunar Surface: A Challenging Problem for DSMC

Science.gov (United States)

Lumpkin, Forrest; Marichalar, Jermiah; Piplica, Anthony

2007-01-01

The President's Vision for Space Exploration calls for the return of human exploration of the Moon. The plans are ambitious and call for the creation of a lunar outpost. Lunar Landers will therefore be required to land near predeployed hardware, and the dust storm created by the Lunar Lander's plume impingement to the lunar surface presents a hazard. Knowledge of the number density, size distribution, and velocity of the grains in the dust cloud entrained into the flow is needing to develop mitigation strategies. An initial step to acquire such knowledge is simulating the associated plume impingement flow field. The following paper presents results from a loosely coupled continuum flow solver/Direct Simulation Monte Carlo (DSMC) technique for simulating the plume impingement of the Apollo Lunar module on the lunar surface. These cases were chosen for initial study to allow for comparison with available Apollo video. The relatively high engine thrust and the desire to simulate interesting cases near touchdown result in flow that is nearly entirely continuum. The DSMC region of the flow field was simulated using NASA's DSMC Analysis Code (DAC) and must begin upstream of the impingement shock for the loosely coupled technique to succeed. It was therefore impossible to achieve mean free path resolution with a reasonable number of molecules (say 100 million) as is shown. In order to mitigate accuracy and performance issues when using such large cells, advanced techniques such as collision limiting and nearest neighbor collisions were employed. The final paper will assess the benefits and shortcomings of such techniques. In addition, the effects of plume orientation, plume altitude, and lunar topography, such as craters, on the flow field, the surface pressure distribution, and the surface shear stress distribution are presented.

Experimental study on boiling heat transfer to an impinging jet on a hot block

International Nuclear Information System (INIS)

Kamata, Choko

1997-01-01

Previous studies on boiling heat transfer by impinging jets are mainly concerned with the impinging point by using small heat transfer surfaces of about 20 mm. An experimental study of the boiling heat transfer to an impinging water jet on a massive hot block is made. The upward heating surface is made of copper. Its diameter and nozzle diameter are 80 mm and 2.2 mm, respectively. The velocity of the impinging jet was varied from 0.6 to 2.1 m/s. Saturated water normally impinged on the heating surface, flowed radially, and subsequently dispersed into the atmosphere. The present study clarifies that heat transfer characteristics vary with the temperature of heat transfer surface, and also with the distance from the impinging point. (author)

Investigation of Characteristics of Impinging Jet for 1/5-Scale ECC injection

Energy Technology Data Exchange (ETDEWEB)

Shin, Byung Soo; Ko, Yung Joo; Bae, Hwang; Kwon, Tae Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-05-15

In ECCS of SMART reactor, safety injection pump discharges cooling water into the core to maintain the water level by filling the amount of loss of coolant under emergency situation such as SBLOCA. Once the ECCS starts to operate, the injected water will be impinged to the upper wall of core support barrel (CBS). And the water will fall along the wall forming liquid film or droplets as shown in Fig. 1(b) due to high Reynolds number. The breakup and film flow will be bypassed by high temperature and pressure steam-water mixture cross flow from RCP discharge into the atmosphere through broken injection nozzle. Then, the flow phenomena in the downcomer is very complex situation with including jet impingement, jet breakup, liquid entrainment, steam condensation, counter-current flow and etc. In this study, the hydraulic features of impinging jet were investigated through visualization for full scale test for simulation of SMART ECC jet and SWAT test of 1/5 simulated test for ECCS of SMART reactor and measurement of the film width. And the scaling method for SWAT test was discussed considering jet break up and other phenomena

Active Control of Supersonic Impinging Jets Using Supersonic Microjets

National Research Council Canada - National Science Library

Alvi, Farrukh

2005-01-01

.... Supersonic impinging jets occur in many applications including in STOVL aircraft where they lead to a highly oscillatory flow with very high unsteady loads on the nearby aircraft structures and the landing surfaces...

Single-phase liquid jet impingement heat transfer

International Nuclear Information System (INIS)

Webb, B.W.; Ma, C.F.

1995-01-01

Impinging liquid jets have been demonstrated to be an effective means of providing high heat/mass transfer rates in industrial transport processes. When a liquid jet strikes a surface, thin hydrodynamic and thermal boundary layers from in the region directly beneath due to the jet deceleration and the resulting increase in pressure. The flow is then forced to accelerate in a direction parallel to the target surface in what is termed the wall jet or parallel flow zone. The thickness of the hydrodynamic and thermal boundary layers in the stagnation region may be of the order of tens of micrometers. Consequently, very high heat/mass transfer coefficients exist in the stagnation zone directly under the jet. Transport coefficients characteristic of parallel flow prevail in the wall jet region. The high heat transfer coefficients make liquid jet impingement an attractive cooling option where high heat fluxes are the norm. Some industrial applications include the thermal treatment of metals, cooling of internal combustion engines, and more recently, thermal control of high-heat-dissipation electronic devices. Both circular and planar liquid jets have attracted research attention. 180 refs., 35 figs., 11 tabs

Numerical study of metal foam heat sinks under uniform impinging flow

International Nuclear Information System (INIS)

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. (paper)

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

2017-12-01

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.

Investigation of Three-Dimensional Axisymmetric Unsteady Stagnation-Point Flow and Heat Transfer Impinging on an Accelerated Flat Plate

OpenAIRE

ali shokrgozar abbasi; Asghar Baradaran Rahimi; Hamidreza Mozayeni

2016-01-01

General formulation and solution of Navier-Stokes and energy equations are sought in the study of threedimensional axisymmetric unsteady stagnation-point flow and heat transfer impinging on a flat plate when the plate is moving with variable velocity and acceleration towards the main stream or away from it. As an application, among others, this accelerated plate can be assumed as a solidification front which is being formed with variable velocity. An external fluid, along z - directi...

A simplified analog for a rotorcraft-in-ground-effect flow using a forced impinging jet

Science.gov (United States)

Geiser, Jayson; Kiger, Ken

2010-11-01

The phenomenon of rotorcraft brown-out is defined as the intense suspension and re-ingestion of sand during the take-off and landing of a rotor-lifted aircraft. To mitigate the problem of rotorcraft brown-out, the non-equilibrium sediment suspension process that occurs within a typical rotorcraft wake must be understood. We attempt to understand the most basic aspects of this complex flow through the use of an axisymmetric forced impinging jet. While this flow neglects the swirl component associated with a rotorcraft, it does reproduce the typical coherent vortex structures, and permits their repeatable generation within an axisymmetric mean stagnation flow. The goal of the current work is to determine the forcing conditions that produce isolated, but intense and repeatable structures that can be followed through their interaction with the wall boundary. Stereo PIV imaging is applied to detail the breakdown of a vortex ring in the wall jet zone. The secondary vortex generation and decay are observed experimentally with 3-D vector fields, and their results are interpreted with respect to their significance in the context of sediment mobilization.

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

International Nuclear Information System (INIS)

Kibar, Ali

2017-01-01

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. (paper)

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

Energy Technology Data Exchange (ETDEWEB)

Kibar, Ali, E-mail: alikibar@kocaeli.edu.tr [Department of Mechanical and Material Technologies, Kocaeli University, Arslanbey Campus, 41285, Kocaeli (Turkey)

2017-02-15

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. (paper)

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.

Perspectives on fish impingement

International Nuclear Information System (INIS)

Sharma, R.K.

1977-01-01

Data on fish impingement and related parameters are being gathered at a large number of power stations throughout the country at substantial monetary and manpower costs. A national survey of fish impingement at power plants was conducted and much of the information compiled in a standardized format--an effort that we think will aid in planning improvements in the design, siting, and operation of the cooling-water intakes. This paper examines the objectives of the fish impingement studies, monitoring programs, variables affecting fish impingement, siting and design criteria, state-of-the-art of screening systems, and suggestions for meeting 316(b) requirements. It also discusses where the emphasis should be placed in future fish-impingement related activities

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)

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

International Nuclear Information System (INIS)

McKendrick, D.; Biggs, S.R.; Fairweather, M.; Rhodes, D.

2008-01-01

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)

Shear layer characteristics of supersonic free and impinging jets

Science.gov (United States)

Davis, T. B.; Kumar, R.

2015-09-01

The initial shear layer characteristics of a jet play an important role in the initiation and development of instabilities and hence radiated noise. Particle image velocimetry has been utilized to study the initial shear layer development of supersonic free and impinging jets. Microjet control employed to reduce flow unsteadiness and jet noise appears to affect the development of the shear layer, particularly near the nozzle exit. Velocity field measurements near the nozzle exit show that the initially thin, uncontrolled shear layer develops at a constant rate while microjet control is characterized by a rapid nonlinear thickening that asymptotes downstream. The shear layer linear growth rate with microjet control, in both the free and the impinging jet, is diminished. In addition, the thickened shear layer with control leads to a reduction in azimuthal vorticity for both free and impinging jets. Linear stability theory is used to compute unstable growth rates and convection velocities of the resultant velocity profiles. The results show that while the convection velocity is largely unaffected, the unstable growth rates are significantly reduced over all frequencies with microjet injection. For the case of the impinging jet, microjet control leads to near elimination of the impingement tones and an appreciable reduction in broadband levels. Similarly, for the free jet, significant reduction in overall sound pressure levels in the peak radiation direction is observed.

Impingement: an annotated bibliography

International Nuclear Information System (INIS)

Uziel, M.S.; Hannon, E.H.

1979-04-01

This bibliography of 655 annotated references on impingement of aquatic organisms at intake structures of thermal-power-plant cooling systems was compiled from the published and unpublished literature. The bibliography includes references from 1928 to 1978 on impingement monitoring programs; impingement impact assessment; applicable law; location and design of intake structures, screens, louvers, and other barriers; fish behavior and swim speed as related to impingement susceptibility; and the effects of light, sound, bubbles, currents, and temperature on fish behavior. References are arranged alphabetically by author or corporate author. Indexes are provided for author, keywords, subject category, geographic location, taxon, and title

Visualization and modeling of the hydrodynamics of an impinging microjet.

Science.gov (United States)

Bitziou, Eleni; Rudd, Nicola C; Edwards, Martin A; Unwin, Patrick R

2006-03-01

The use of fluorescence confocal laser scanning microscopy (CLSM) for flow visualization is described, with a focus on elucidating the pattern of flow in the microjet electrode (MJE). The MJE employs a nozzle, formed from a fine glass capillary, with an inner diameter of approximately 100 microm, to direct solution at an electrode surface, using high velocity but at moderate volume flow rates. For CLSM visualization, the jetted solution contains a fluorescent probe, fluorescein at high pH, which flows into a solution buffered at low pH, where the fluorescence is extinguished, thereby highlighting the flow field of the impinging microjet. The morphology of the microjet and the hydrodynamic boundary layer are shown to be highly sensitive to the volume flow rate, with a collimated jet and thin boundary layer formed at the faster flow rates (approximately 1 cm(3) min(-1)). In contrast, at lower flow rates and for relatively large substrates, an unusual recirculation zone is observed experimentally for the first time. This effect can be eliminated by employing small substrates. The experimental observations have been quantified through numerical solution of the Navier-Stokes equations of continuity and momentum balance. The new insights provided by CLSM imaging demonstrate that flow in the MJE, and impinging jets in general, are more complex than predicted by classical models but are well-defined and quantifiable.

Characteristics of steam jet impingement on annulus

International Nuclear Information System (INIS)

Yoon, Sang H.; Kim, Won J.; Suh, Kune Y.; Song, Chul H.

2004-01-01

The steam jet impingement occurs when the steam through the cold leg from the steam generator strikes the inner reactor barrel during the reflood phase of a loss-of-coolant accident (LOCA), which is a characteristic behavior for the APR1400 (Advanced Power Reactor 1400 MWe). In the cold leg break LOCA, the steam and water flows in the downcomer are truly multidimensional. The azimuthal velocity distribution of the steam flow has an important bearing on the thermal hydraulic phenomena such as the emergency coolant water direct bypass, sweepout, steam condensation, and so forth. The investigation of jet flow is required to determine the steam path and momentum reduction rate after the impingement. For the observation of the steam behavior near the break, the computational fluid dynamic (CFD) analysis has been carried out using CFX5.6. The flow visualization and analysis demonstrate the velocity profiles of the steam flow in the annulus region for the same boundary conditions. Pursuant to the CFD results, the micro-Pitot tubes were positioned at varying angles, and corrected for their sensitivity. The experiments were carried out to directly measure the pressure differential and to visualize the flow utilizing a smoke injection method. Results from this study are slated to be applied to MARS, which is a thermal hydraulic system code for the best-estimate analysis. The current one- or two-dimensional analysis in MARS was known to distort the local flow behavior. To enhance prediction capability of MARS, it is necessary to inspect the steam path in the break flow and mechanically simulate the momentum variation. The present experimental and analytical results can locally be applied to developing the engineering models of specific and essential phenomena. (author)

Steam exit flow design for aft cavities of an airfoil

Science.gov (United States)

Storey, James Michael; Tesh, Stephen William

2002-01-01

Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

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

Effect of guide wall on jet impingement cooling in blade leading edge channel

International Nuclear Information System (INIS)

Zhao, Qing-Yang; Chung, Heeyoon; Choi, Seok Min; Cho, Hyung Hee

2016-01-01

The characteristics of fluid flow and heat transfer, which are affected by the guide wall in a jet impinged leading edge channel, have been investigated numerically using three-dimensional Reynolds-averaged Navier-Stokes analysis via the shear stress transport turbulence model and gamma theta transitional turbulence model. A constant wall heat flux condition has been applied to the leading edge surface. The jet-to-surface distance is constant, which is three times that of the jet diameter. The arrangement of the guide wall near the jet hole is set as a variable. Results presented in this study include the Nusselt number contour, velocity vector, streamline with velocity, and local Nusselt number distribution along the central line on the leading edge surface. The average Nusselt number and average pressure loss between jet nozzle and channel exit are calculated to assess the thermal performance. The application of the guide wall is aimed at improving heat transfer uniformity on the leading edge surface. Results indicated that the streamwise guide wall ensures the vertical jet impingement flow intensity and prevents the flow after impingement to reflux into jet flow. Thus, a combined rectangular guide wall benefits the average heat transfer, thermal performance and heat transfer distribution uniformity

Flow Structure and Heat Transfer of Jet Impingement on a Rib-Roughened Flat Plate

Directory of Open Access Journals (Sweden)

Abdulrahman H. Alenezi

2018-06-01

Full Text Available The jet impingement technique is an effective method to achieve a high heat transfer rate and is widely used in industry. Enhancing the heat transfer rate even minimally will improve the performance of many engineering systems and applications. In this numerical study, the convective heat transfer process between orthogonal air jet impingement on a smooth, horizontal surface and a roughened uniformly heated flat plate is studied. The roughness element takes the form of a circular rib of square cross-section positioned at different radii around the stagnation point. At each location, the effect of the roughness element on heat transfer rate was simulated for six different heights and the optimum rib location and rib dimension determined. The average Nusselt number has been evaluated within and beyond the stagnation region to better quantify the heat transfer advantages of ribbed surfaces over smooth surfaces. The results showed both flow and heat transfer features vary significantly with rib dimension and location on the heated surface. This variation in the streamwise direction included both augmentation and decrease in heat transfer rate when compared to the baseline no-rib case. The enhancement in normalized averaged Nusselt number obtained by placing the rib at the most optimum radial location R/D = 2 was 15.6% compared to the baseline case. It was also found that the maximum average Nusselt number for each location was achieved when the rib height was close to the corresponding boundary layer thickness of the smooth surface at the same rib position.

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.

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.

Femoroacetabular impingement

International Nuclear Information System (INIS)

Anderson, Suzanne E.; Siebenrock, Klaus Arno; Tannast, Moritz

2012-01-01

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.

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.

Performance analysis of solar air heater with jet impingement on corrugated absorber plate

Directory of Open Access Journals (Sweden)

Alsanossi M. Aboghrara

2017-09-01

Full Text Available This paper deals with the experimental investigation outlet temperature and efficiency, of Solar Air heater (SAH. The experimental test set up designed and fabricated to study the effect of jet impingement on the corrugated absorber plate, through circular jets in a duct flow of solar air heater, and compared with conventional solar air heater on flat plat absorber. Under effect of mass flow rate (ṁ of air and solar radiation on outlet air temperature, and efficiency, are analyzed. Results show the flow jet impingement on corrugated plat absorber is a strong function of heat transfer enhancement. The present investigation concludes that the mass flow rate of air substantially influences the heat transfer on solar air heaters. And the thermal efficiency of proposed design duct is observed almost 14% more as compare to the smooth duct. At solar radiation 500–1000 (W/M2, 308 K ambient temperature and 0.01–0.03 (Kg/S mass flow rate

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.

Numerical study of heat transfer enhancement due to the use of fractal-shaped design for impingement cooling

Directory of Open Access Journals (Sweden)

Cai Lin

2017-01-01

Full Text Available This paper describes a numerical analysis of a heat transfer enhancement technique that introduces fractal-shaped design for impingement cooling. Based on the gas turbine combustion chamber cooling, a fractal-shaped nozzle is designed for the constant flow area in a single impingement cooling model. The incompressible Reynolds-averaged Navier-Stokes equations are applied to the system using CFD software. The numerical results are compared with the experiment results for array impingement cooling.

Study of microburst-induced wind flow and its effects on cube-shaped buildings using numerical and experimental simulations of an impinging jet

Science.gov (United States)

Sengupta, Anindya

Microbursts are a major cause of concern for structures both on ground as well as those in air, namely aircrafts. The velocity profile of a microburst is completely different compared to natural boundary-layer wind profiles. The current research is directed to simulation of microburst phenomenon using an impinging jet model. This research reports the first 3D numerical simulation of microbursts and its effects on buildings. Broadly the major accomplishments of the current research can be focused in three major directions. In the first case, extensive research on velocity profiles of the wall jet that is formed after jet impingement has been conducted experimentally. The main motivation was to develop empirical equations for boundary layer growth based on experimental data, using hot-wire, PIV and pressure rake. Numerical simulations were carried out with different turbulence models so as to find the best turbulence model to simulate this kind of flow. In the second case, both mean and peak loads on building models under static microburst wind loadings were studied, using both experimental as well as numerical techniques. Parametric study by varying the height of jet impingement, jet exit velocities and size of building models was conducted. It was found that the large eddy simulation (LES) produced results in excellent agreement with the experimental data. The flow field around the building model was obtained using PIV and comparisons were made with the LES results. Thirdly, and the most important part of this research work was to simulate a translating microburst and study the loads on buildings using a moving impinging jet. Numerical simulation was validated with the experimental data for one jet translation speed. LES results again matched the experimental data for translating microburst loads on building, with reference to the drag and lift coefficients. The peak loads predicted by LES were within experimental limits. Effects of increased jet translation speeds

Development of Augmented Spark Impinging Igniter System for Methane Engines

Science.gov (United States)

Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

2017-01-01

The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. NASA can share technology and expertise under the SAA for the benefit of the CATALYST partners. MSFC seeking to vacuum test Augmented Spark Impinging (ASI) igniter with methane and new exciter units to support CATALYST partners and NASA programs. ASI has previously been used/tested successfully at sea-level, with both O2/CH4 and O2/H2 propellants. Conventional ignition exciter systems historically experienced corona discharge issues in vacuum. Often utilized purging or atmospheric sealing on high voltage lead to remedy. Compact systems developed since PCAD could eliminate the high-voltage lead and directly couple the exciter to the spark igniter. MSFC developed Augmented Spark Impinging (ASI) igniter. Successfully used in several sea-level test programs. Plasma-assisted design. Portion of ox flow is used to generate hot plasma. Impinging flows downstream of plasma. Additional fuel flow down torch tube sleeve for cooling near stoichiometric torch flame. Testing done at NASA GRC Altitude Combustion Stand (ACS) facility 2000-lbf class facility with altitude simulation up to around 100,000 ft. (0.2 psia [10 Torr]) via nitrogen driven ejectors. Propellant conditioning systems can provide temperature control of LOX/CH4 up to test article.

Annular Impinging Jet Controlled by Radial Synthetic Jets

Czech Academy of Sciences Publication Activity Database

Trávníček, Zdeněk; Tesař, Václav; Broučková, Zuzana; Peszyński, K.

2014-01-01

Roč. 35, 16-17 (2014), s. 1450-1461 ISSN 0145-7632 R&D Projects: GA ČR GA14-08888S; GA AV ČR(CZ) IAA200760801 Institutional support: RVO:61388998 Keywords : impinging jet * hybrid synthetic jet * flow control Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts Impact factor: 0.814, year: 2014 http://dx.doi.org/10.1080/01457632.2014.889467

Numerical study of a hybrid jet impingement/micro-channel cooling scheme

International Nuclear Information System (INIS)

Barrau, Jérôme; Omri, Mohammed; Chemisana, Daniel; Rosell, Joan; Ibañez, Manel; Tadrist, Lounes

2012-01-01

A new hybrid jet impingement/micro-channel cooling scheme is studied numerically for use in high-heat-flux thermal management of electronic and power devices. The device is developed with the objective of improving the temperature uniformity of the cooled object. A numerical model based on the k–ω SST turbulent model is developed and validated experimentally. This model is used to carry out a parametrical characterization of the heat sink. The study shows that variations in key parameters of jet impingement and micro-channel technologies allow for the cooling scheme to obtain a wide range of temperature profiles for the cooled object. - Highlights: ► A new hybrid cooling scheme is numerically studied. ► The cooling scheme combines the benefits of jet impingement and micro-channel flows. ► The numerical model is validated by comparison with experimental results. ► The temperature distribution can be adapted to the needs of the cooled system.

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

International Nuclear Information System (INIS)

Figueiredo, Marcia A.O.; Eide, Ingvar; Reynier, Marcia; Villas-Bôas, Alexandre B.; Tâmega, Frederico T.S.

2015-01-01

Highlights: • Collection of rhodoliths and calcareous algae from Campos Basin, Brazil. • Impact of sediment mimicking drill cuttings on photosynthetic efficiency. • Exposure–response for photosynthetic efficiency as function of sediment coverage. • Factorial design and multivariate regression used for a structured approach. - Abstract: The impact of sediment coverage on two rhodolith-forming calcareous algae species collected at 100 m 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, ϕ PSIImax ) 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 1–2 weeks 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

Impinging jet spray formation using non-Newtonian liquids

Science.gov (United States)

Rodrigues, Neil S.

Over the past two decades there has been a heightened interest in implementing gelled propellants for rocket propulsion, especially for hypergolic bi-propellants such as monomethylhydrazine (MMH) and nitrogen tetroxide oxidizer (NTO). Due to the very high level of toxicity of hypergolic liquid rocket propellants, increasing safety is an important area of need for continued space exploration and defense operations. Gelled propellants provide an attractive solution to meeting the requirements for safety, while also potentially improving performance. A gelling agent can be added to liquid propellants exhibiting Newtonian behavior to transform the liquid into a non-Newtonian fluid with some solid-like behavior, i.e. a gel. Non-Newtonian jet impingement is very different from its Newtonian counterpart in terms of fluid flow, atomization, and combustion. This is due to the added agents changing physical properties such as the bulk rheology (viscosity) and interfacial rheology (surface tension). Spray characterization of jet impingement with Newtonian liquids has been studied extensively in existing literature. However, there is a scarcity in literature of studies that consider the spray characterization of jet impingement with gelled propellants. This is a rather critical void since a major tradeoff of utilizing gelled propellants is the difficulty with atomization due to the increased effective viscosity. However, this difficulty can be overcome by using gels that exhibit shear-thinning behavior---viscosity decreases with increasing strain rate. Shear-thinning fluids are ideal because they have the distinct advantage of only flowing easily upon pressure. Thereby, greatly reducing the amount of propellant that could be accidentally leaked during both critical functions such as liftoff or engagement in the battlefield and regular tasks like refilling propellant tanks. This experimental work seeks to help resolve the scarcity in existing literature by providing drop size

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.

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 I SC 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.

Impingement syndrome of the shoulder

International Nuclear Information System (INIS)

Mayerhoefer, M.E.; Breitenseher, M.J.

2004-01-01

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.) [de

Femoroacetabular impingement surgery

DEFF Research Database (Denmark)

Reiman, Michael P; Thorborg, Kristian

2015-01-01

both the examination and treatment of FAI does not appear to accommodate this exponential growth. In fact, the direction currently taken for FAI is similar to previously described paths of other orthopaedic and sports medicine pathologies (eg, shoulder impingement, knee meniscus tear) for which we have......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...

Hot air impingement on a flat plate using Large Eddy Simulation (LES) technique

Science.gov (United States)

Plengsa-ard, C.; Kaewbumrung, M.

2018-01-01

Impinging hot gas jets to a flat plate generate very high heat transfer coefficients in the impingement zone. The magnitude of heat transfer prediction near the stagnation point is important and accurate heat flux distribution are needed. This research studies on heat transfer and flow field resulting from a single hot air impinging wall. The simulation is carried out using computational fluid dynamics (CFD) commercial code FLUENT. Large Eddy Simulation (LES) approach with a subgrid-scale Smagorinsky-Lilly model is present. The classical Werner-Wengle wall model is used to compute the predicted results of velocity and temperature near walls. The Smagorinsky constant in the turbulence model is set to 0.1 and is kept constant throughout the investigation. The hot gas jet impingement on the flat plate with a constant surface temperature is chosen to validate the predicted heat flux results with experimental data. The jet Reynolds number is equal to 20,000 and a fixed jet-to-plate spacing of H/D = 2.0. Nusselt number on the impingement surface is calculated. As predicted by the wall model, the instantaneous computed Nusselt number agree fairly well with experimental data. The largest values of calculated Nusselt number are near the stagnation point and decrease monotonically in the wall jet region. Also, the contour plots of instantaneous values of wall heat flux on a flat plate are captured by LES simulation.

Excitational metamorphosis of surface flowfield under an impinging annular jet

Czech Academy of Sciences Publication Activity Database

Tesař, Václav; Trávníček, Zdeněk

2008-01-01

Roč. 144, č. 2 (2008), s. 312-316 ISSN 1385-8947 R&D Projects: GA ČR GA101/07/1499; GA AV ČR IAA200760705 Institutional research plan: CEZ:AV0Z20760514 Keywords : jets * impinging jets * flow topology * annular jets * stagnation points Subject RIV: BK - Fluid Dynamics Impact factor: 2.813, year: 2008 http://www.sciencedirect.com/

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 regi...

Imaging findings of femoroacetabular impingement syndrome

International Nuclear Information System (INIS)

Beall, Douglas P.; Sweet, Clifford F.; Martin, Hal D.; Lastine, Craig L.; Grayson, David E.; Ly, Justin Q.; Fish, Jon R.

2005-01-01

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.)

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.)

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.

On angled bounce-off impact of a drop impinging on a flowing soap film

Science.gov (United States)

Basu, Saikat; Yawar, Ali; Concha, Andres; Bandi, M. M.

2017-12-01

Small drops impinging obliquely on thin flowing soap films frequently demonstrate the rare emergence of bulk elastic effects working in-tandem with the more commonplace hydrodynamic interactions. Three collision regimes are observable: (a) drop piercing through the film, (b) it coalescing with the flow, and (c) it bouncing off the film surface. During impact, the drop deforms along with a bulk elastic deformation of the film. For impacts that are close-to-tangential, the bounce-off regime predominates. We outline a reduced order analytical framework assuming a deformable drop and a deformable three-dimensional film, and the idealization invokes a phase-based parametric study. Angular inclination of the film and the ratio of post and pre-impact drop sizes entail the phase parameters. We also perform experiments with vertically descending droplets (constituted from deionized water) impacting against an inclined soap film, flowing under constant pressure head. Model-predicted phase domain for bounce-off compares well to our experimental findings. Additionally, the experiments exhibit momentum transfer to the film in the form of shed vortex dipoles, along with propagation of free surface waves. On consulting prior published work, we note that for locomotion of water-walking insects using an impulsive action, the momentum distribution to the shed vortices and waves are both significant, taking up respectively 2/3 and 1/3 of the imparted streamwise momentum. Considering the visually similar impulse actions, this theory, despite its assumption of a quiescent liquid bath of infinite depth, is applied to the drop bounce-off experiments, and the resultant shed vortex dipole momenta are compared to the momenta of the coherent vortex structures computed from particle imaging velocimetry data. The magnitudes reveal identical order (10-7 N s), suggesting that notwithstanding the disparities, the bounce-off regime may be tapped as a toy analog for impulse-based interfacial

An Investigation of Fuel Mixing and Reaction in a CH4/Syngas/Air Premixed Impinging Flame with Varied H2/CO Proportion

Directory of Open Access Journals (Sweden)

Chih-Pin Chiu

2017-07-01

Full Text Available For industrial applications, we propose a concept of clean and efficient combustion through burning syngas on an impinging burner. We performed experimental measurements of particle image velocimetry, OH radical (OH* chemiluminescence, flame temperature, and CO emission to examine the fuel mixing and reaction of premixed impinging flames of CH4/syngas/air with H2/CO in varied proportions. The velocity distribution of the combustion flow field showed that a deceleration area in the main flow formed through the mutual impingement of two jet flows, which enhanced the mixing of fuel and air because of an increased momentum transfer. The deceleration area expanded with an increased CO proportion, which indicated that the mixing of fuel and air also increased with the increased CO proportion. Our examination of the OH* chemiluminescence demonstrated that its intensity increased with increased CO proportion, which showed that the reaction between fuel and air accordingly increased. CO provided in the syngas hence participated readily in the reaction of the CH4/syngas/air premixed impinging flames when the syngas contained CO in a large proportion. Although the volume flow rate of the provided CO quadrupled, the CO emission increased by only 12% to 15%. The results of this work are useful to improve the feasibility of fuel-injection systems using syngas as an alternative fuel.

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.

Fish impingement at Lake Michigan power plants

International Nuclear Information System (INIS)

Sharma, R.K.; Freeman, R.F.; Spigarelli, S.A.

1976-01-01

A study was initiated in 1974 to survey the magnitude and to evaluate the impact of fish impingement at 20 power plants on the Great Lakes. Data on impingement rates, site characteristics, intake designs and operational features have been collected and analyzed. Interpretive analyses of these data are in progress. The objectives of this study were: to summarize fish impingement data for Lake Michigan (16/20 plants surveyed are on Lake Michigan); to assess the significance of total and source-related mortalities on populations of forage and predator species; and to expand the assessment of power plant impingement to include all water intakes on Lake Michigan. Data are tabulated

Study on pipe wastage mechanism by liquid droplet impingement erosion

International Nuclear Information System (INIS)

Higashi, Yuma; Narabayashi, Tadashi; Shimazu, Yoichiro; Tsuji, Masashi; Ohmori, Shuichi; Mori, Michitsugu; Tezuka, Kenichi

2009-01-01

Evaluation of wastage speed for nuclear power plant maintains plant reliability and power up rating is important. There are two main cause of wastage flow accelerated corrosion (FAC) and mechanical erosion. This study is to develop evaluating the wastage speed by liquid droplet impingement erosion (LDIE). LDIE often occurs at downstream of corner of pipe or orifice. In this study, the liquid drop impinging tests were conducted with the test pieces mounted on a high speed rotating disk that cross thin water down jet and produced LDIE phenomena. The amount of the wastage by LDIE was evaluated by changing the rotational speed, the impingement frequency, and test piece materials. In addition, the generation mechanism of erosion was investigated by observing the surface of the test piece with a microscope. There is a method of evaluating by the mass difference before and after experiments. But this method is not correct because error becomes larger for mass measurement in the experiment, for the lost mass by LDIE is very little amount. Therefore, the method was developed to measure the volume in the erosion part. In this method, depth of LDIE was measured by the accuracy of ±0.01μm; therefore accurate measurement of the wastage can be improved. (author)

Temporally stratified sampling programs for estimation of fish impingement

International Nuclear Information System (INIS)

Kumar, K.D.; Griffith, J.S.

1977-01-01

Impingement monitoring programs often expend valuable and limited resources and fail to provide a dependable estimate of either total annual impingement or those biological and physicochemical factors affecting impingement. In situations where initial monitoring has identified ''problem'' fish species and the periodicity of their impingement, intensive sampling during periods of high impingement will maximize information obtained. We use data gathered at two nuclear generating facilities in the southeastern United States to discuss techniques of designing such temporally stratified monitoring programs and their benefits and drawbacks. Of the possible temporal patterns in environmental factors within a calendar year, differences among seasons are most influential in the impingement of freshwater fishes in the Southeast. Data on the threadfin shad (Dorosoma petenense) and the role of seasonal temperature changes are utilized as an example to demonstrate ways of most efficiently and accurately estimating impingement of the species

Hip morphology predicts posterior hip impingement in a cadaveric model.

Science.gov (United States)

Morris, William Z; Fowers, Cody A; Weinberg, Douglas S; Millis, Michael B; Tu, Leigh-Anne; Liu, Raymond W

2018-05-01

Posterior hip impingement is a recently-identified cause of hip pain. The purpose of this study is to characterise posterior femoroacetabular and ischiofemoral impingement and identify its predisposing morphologic traits. Two hundred and six cadaveric hips were randomly selected and taken through controlled motion in two pure axes associated with posterior hip impingement: external rotation (through the mechanical axis) and adduction (coronal plane). The range of motion and location of impingement was noted for each specimen. Morphologic traits including femoral/acetabular version, and true neck-shaft angle (TNSA) were also measured. External rotation impingement occurred between the femoral neck and acetabulum in 83.0% of hips, and between the lesser trochanter and ischial tuberosity in 17.0%. Adduction impingement occurred between the lesser trochanter and ischial tuberosity in 78.6% of hips, and between the femoral neck and acetabulum in 21.4%. Multiple regression revealed that increased femoral/acetabular version predicted earlier external rotation and adduction impingement. Unstandardised betas ranging from -0.39 to -0.64 reflect that each degree of increased femoral/acetabular version individually accounts for a loss of external rotation or adduction of approximately half a degree before impingement ( p < 0.001 for each). Increased TNSA was associated with earlier adduction impingement only (unstandardised beta -0.35, p = 0.005). Relative femoral/acetabular anteversion was associated with earlier posterior hip impingement. Coxa valga was associated with earlier adduction impingement, but protective against external rotation impingement. These findings highlight the importance of monitoring correction during femoral/acetabular osteotomies, as overcorrection of retroversion may predispose to earlier posterior impingement.

Experimental investigation on the performance of an impinging jet solar air heater

Directory of Open Access Journals (Sweden)

T. Rajaseenivasan

2017-03-01

Full Text Available Investigation on an impinging jet solar air heater is performed and reported in this work. The air is supplied through an impinging jet pipe which contains the nozzles to distribute the air in the solar air heater. The air is released from the jet strikes the absorber plate which increases the heat transfer rate by creating turbulent flow in the collector. This study is focused on the parameters that affect the heat transfer characteristics and compared with conventional solar air heater. The system is examined by varying the angle of attack (0°, 10°, 20°, 30°, 60° and 90° and the nozzle diameter (3 mm, 5 mm and 7 mm in the air mass flow rate range of 0.012–0.016 kg/s. The study revealed that the highest performance is achieved with the 30° angle of attack, and the lowest performance is recorded with the 0°. The reduction in jet diameter increases the pressure loss in the collector. The better system performance is observed with the 5 mm diameter hole. The maximum thermal enhancement factor of 2.19 and efficiency of 55.8% are reached with the flow rate of 0.016 kg/s.

Pollutant emission and noise radiation from open and impinging inverse diffusion flames

International Nuclear Information System (INIS)

Choy, Y.S.; Zhen, H.S.; Leung, C.W.; Li, H.B.

2012-01-01

Highlights: ► The effect of burner geometry (d air and S) on inverse diffusion flames is studied. ► With fixed air/fuel supplies, a smaller d air curtails NO x emission but augments noise radiation. ► With fixed air/fuel supplies, a larger S reduces NO x emission but increases noise radiation. ► Both NO x emission and noise radiation are maximum under stoichiometric combustion. ► Impinging flames are nosier than corresponding open flames due to the mirror effect of the plate. -- Abstract: This paper reports an experimental investigation of the pollutant emission and noise radiation characteristics of both open and impinging inverse diffusion flames (IDFs), produced by five burners of different air port diameter (d air = 5, 6 and 6.84 mm) and air-to-fuel spacing (S = 8, 11.5 and 15 mm). The effects of d air , S, overall equivalence ratio φ and nozzle-to-plate spacing H on the pollutant emissions of CO and NO x and the noise radiation are examined. The results show that at fixed air flow rate, a smaller d air curtails NO x emission but augments noise radiation, indicative of a role played by turbulence, which tends to decrease pollutant emission and increase noise radiation. A larger S reduces NO x emission but increases noise radiation, indicating that different flame zones may be responsible for pollutant emission and noise radiation. When the IDF is under stoichiometric φ = 1.6, both the NO x emission and noise radiation are highest, as a result of maximum heat release rate. A comparison of EINO x for the open and impinging IDFs shows that the impinging IDFs emit more NO x probably due to the absence of NO reburning. The impinging IDFs have higher noise radiation than the corresponding open IDFs. A higher level of noise radiation from the impinging IDFs is observed as the target plate is brought closer to the burner.

Buoyancy effects laminar slot jet impinging on a surface with constant heat flux

International Nuclear Information System (INIS)

Shokouhmand, H.; Esfahanian, V.; Masoodi, R.

2004-01-01

The two-dimensional laminar air jet issuing from a nozzle of half which terminates at height above a flat plate normal to the jet is numerically on the flow and thermal structure of the region near impingement. The impinging surface is maintained at a constant heat flux condition. The full Navier-Stocks and energy equations are solved by a finite difference method to evaluate the velocity profiles and temperature distribution. The governing parameters and their ranges are: Reynolds number Re, 10-50, Grashof number Gr, 0-50, Richardson number Ri=Gr/ Re 2 , Non dimensional nozzle height H,2-3. Results of the free streamline, local friction factor and heat transfer coefficient are graphically presented. It is found that enhancement of the heat transfer rate is substantial for high Richardson number conditions. Although the laminar jet impingement for isothermal condition has been already studied, however the constant heat flux has not been studied enough. the present paper will analyze a low velocity air jet, Which can be used for cooling of a simulated electronics package

Numerical study of the spray impingement onto a solid wall

OpenAIRE

Rodrigues, Christian Michel Gomes

2011-01-01

The modelling of turbulent multiphase flows has been gathering high interest in the last decades in the scientific community due to its relevance in several applications, such as in industrial and environmental processes or for chemical and biomedical purposes. In fact, regarding the industrial applications, the impingement of liquid fuel sprays onto engine surfaces has become a subject of interest due to its influence on the mixture preparation prior to combustion and, consequently, engine p...

Comparison study of exhaust plume impingement effects of small mono- and bipropellant thrusters using parallelized DSMC method.

Directory of Open Access Journals (Sweden)

Kyun Ho Lee

Full Text Available A space propulsion system is important for the normal mission operations of a spacecraft by adjusting its attitude and maneuver. Generally, a mono- and a bipropellant thruster have been mainly used for low thrust liquid rocket engines. But as the plume gas expelled from these small thrusters diffuses freely in a vacuum space along all directions, unwanted effects due to the plume collision onto the spacecraft surfaces can dramatically cause a deterioration of the function and performance of a spacecraft. Thus, aim of the present study is to investigate and compare the major differences of the plume gas impingement effects quantitatively between the small mono- and bipropellant thrusters using the computational fluid dynamics (CFD. For an efficiency of the numerical calculations, the whole calculation domain is divided into two different flow regimes depending on the flow characteristics, and then Navier-Stokes equations and parallelized Direct Simulation Monte Carlo (DSMC method are adopted for each flow regime. From the present analysis, thermal and mass influences of the plume gas impingements on the spacecraft were analyzed for the mono- and the bipropellant thrusters. As a result, it is concluded that a careful understanding on the plume impingement effects depending on the chemical characteristics of different propellants are necessary for the efficient design of the spacecraft.

Diagnosis of shoulder impingement syndrome

International Nuclear Information System (INIS)

Hodler, J.

1996-01-01

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.) [de

Influence of thermal gradient on gas turbine combustor wall using impingement/effusion cooling techniques: CHT CFD predictions

Directory of Open Access Journals (Sweden)

A. M. El-jummah

2017-04-01

Full Text Available Internal wall heat transfer relevant to impingement/effusion cooling techniques was investigated using conjugate heat transfer (CHT computational fluid dynamics (CFD with ANSYS Fluent and ICEM commercial software. This work concentrates on the development of CHT CFD design procedures that are applicable to combustor wall and turbine blade heat transfer optimisation in gas turbine (GT. It specifically modelled and compares two configuration which are specifically relevant to the impingement and effusion holes density n (m-2 and is the ratio of the hole pitch X2. The configurations investigated are equal and unequal impingement and effusion holes density n (m-2, respectively, whereby in each case the variation in the number of cooling holes were carried out. The ratio of impingement and effusion number of holes/m2 (or hole density n, investigated were impingement/effusion: 4306/4306 and 1076/4306, respectively. The geometries were for impingement wall, hole pitch X to diameter D, X/D ratio of ~ 11 but different number of holes N for both n geometries, at a constant offset effusion wall, hole X/D of 4.7 of the same N for both the two configurations. The model geometries have a constant impingement gap of 8 mm with both impingement and effusion walls at 6.35 mm thick Nimonic - 75 material and were computed for varied air mass flux G from 0.1 - 0.94 kg/sm2. Symmetrical applications were employed in modelling each of the geometry, whereby for the impingement hole, only quarter of one hole was modelled, while for the effusion side the holes were either quarter or half modelled. The two n geometries were computed with k - ɛ turbulence model using standard wall functions, which also applies to all G. The predicted locally surface X2 (or hole square area average heat transfer coefficient (HTC h values compared with with previously published experimental data showed good agreement. The reduced internal gap flow recirculation with reduced heat transfer to

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.

Impingement of juvenile and adult fishes during cooling water withdrawal

International Nuclear Information System (INIS)

McFarlane, R.W.

1978-01-01

Juvenile and adult fishes are impinged upon trash removal screens as Savannah River water is withdrawn for use on the Savannah River Plant (SRP). Thirty-six species of fish, representing half of all riverine species known from the area, were impinged on the screens at three SRP pumping stations during 1977. Based on the average of 11.2 fish impinged per day, annual impingement is estimated to be 4088 fish. SRP thus ranks third lowest for impingement recently reported for 33 electric power plants

Empirical model of impingement impact. Environmental Sciences Division publication No. 1289

International Nuclear Information System (INIS)

Barnthouse, L.W.; DeAngelis, D.L.; Christensen, S.W.

1979-01-01

A simple model, derived from Ricker's (1975) theory of fisheries dynamics, that can be used to estimate the impact of impingement of juvenile fish by power plants on year-class abundance in vulnerable species is described. The only data required are estimates of the initial number of impingeable juveniles, the number impinged, and the rate of total mortality during the period of vulnerability. The impact of impingement is expressed in the model as the conditional mortality rate, rather than the more commonly used exploitation rate. The conditional mortality rate is superior as a measure of impact for two reasons: it accounts for the differential impact of impinging fish of different ages, and it is numerically equivalent to the fractional reduction in year-class abundance due to impingement. We present an application of the model using the 1974 year-class of the Hudson River striped bass population as an example. We then show how the model can be modified to account for seasonal fluctuations in the rate of impingement, discuss the effect of these fluctuations on the calculated impact, and discuss the influence on model output of errors in the measurement of abundance, impingement, and total mortality. It is evident from this analysis that estimates of impingement impact are as sensitive to errors in estimates of population size and mortality as to estimates of the number of fish impinged. Thus, it is not possible to reliably estimate the impact of impingement on a vulnerable fish species unless a substantial effort is devoted to population studies

A study on post impingement effects of urea-water solution spray on the heated wall of automotive SCR systems

Science.gov (United States)

Shahariar, G. M. H.; Wardana, M. K. A.; Lim, O. T.

2018-04-01

The post impingement effects of urea-water solution spray on the heated wall of automotive SCR systems was numerically investigated in a constant volume chamber using STAR CCM+ CFD code. The turbulence flow was modelled by realizable k-ε two-layer model together with standard wall function and all y+ treatment was applied along with two-layer approach. The Eulerian-Lagrangian approach was used for the modelling of multi phase flow. Urea water solution (UWS) was injected onto the heated wall for the wall temperature of 338, 413, 473, 503 & 573 K. Spray development after impinging on the heated wall was visualized and measured. Droplet size distribution and droplet evaporation rates were also measured, which are vital parameters for the system performance but still not well researched. Specially developed user defined functions (UDF) are implemented to simulate the desired conditions and parameters. The investigation reveals that wall temperature has a great impact on spray development after impingement, droplet size distribution and evaporation. Increasing the wall temperature leads to longer spray front projection length, smaller droplet size and faster droplet evaporation which are preconditions for urea crystallization reduction. The numerical model and parameters are validated comparing with experimental data.

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.

Atomization of Impinging Droplets on Superheated Superhydrophobic Surfaces

Science.gov (United States)

Emerson, Preston; Crockett, Julie; Maynes, Daniel

2017-11-01

Water droplets impinging smooth superheated surfaces may be characterized by dynamic vapor bubbles rising to the surface, popping, and causing a spray of tiny droplets to erupt from the droplet. This spray is called secondary atomization. Here, atomization is quantified experimentally for water droplets impinging superheated superhydrophobic surfaces. Smooth hydrophobic and superhydrophobic surfaces with varying rib and post microstructuring were explored. Each surface was placed on an aluminum heating block, and impingement events were captured with a high speed camera at 3000 fps. For consistency among tests, all events were normalized by the maximum atomization found over a range of temperatures on a smooth hydrophobic surface. An estimate of the level of atomization during an impingement event was created by quantifying the volume of fluid present in the atomization spray. Droplet diameter and Weber number were held constant, and atomization was found for a range of temperatures through the lifetime of the impinging droplet. The Leidenfrost temperature was also determined and defined to be the lowest temperature at which atomization ceases to occur. Both atomization and Leidenfrost temperature increase with decreasing pitch (distance between microstructures).

Flowfield Behavior of Supersonic Impinging Jets

Science.gov (United States)

Iyer, K. G.; Alvi, F. S.

1998-11-01

A detailed study is being conducted which examines the behavior of normally impinging, supersonic jets, issuing from axisymmetric a Mach 1.5 C-D and a sonic nozzle. Our goal is to understand the physics of this flowfield (commonly observed in STOVL aircraft) and its influence on the acoustic and aerodynamic loading on the ground plane and the airframe. The airframe is simulated by a circular disc ('lift' plate) with an annular hole from which the jet is issued. Tests are carried out for a wide range of pressure ratios and the ground plane distance is varied from 1.5 to 60 nozzle diameters. Flowfield measurements include Particle Image Velocimetry (PIV) and schlieren/shadowgraph visualization. Surface measurements on the ground and lift plates include mean and unsteady surface pressure distributions and the surface streamline visualization. Near-field acoustic measurements using a microphone are also obtained. For certain cases, the PIV measurements -- first of their kind, to our knowledge -- clearly show the presence of large-scale coherent turbulent structures which, upon jet impingement, propagate into the resulting wall jet. These structures are believed to generate very high unsteady pressure loads on the ground plane thus leading to ground erosion. They are also suspected to be the source of acoustic waves which lead to a feedback loop causing violent oscillations of the primary jet and can result in increased acoustic loading and subsequent damage to the aircraft. As a result of this detailed study over a wide parametric space, we hope to gain a much better understanding of the physical mechanisms governing this complex flow.

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

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.)

Experimental investigation of submerged single jet impingement using Cu–water nanofluid

International Nuclear Information System (INIS)

Li Qiang; Xuan Yimin; Yu Feng

2012-01-01

Jet impingement cooling is a vital technique for thermal management of electronic devices of high-heat-flux by impinging fluid on a heater surface due to its high local heat transfer rates. In this paper, two types of Cu–water nanofluids (Cu particles with 25 nm diameter or 100 nm) are introduced into submerged single jet impingement cooling system as the working fluid. The heat transfer features of the nanofluids were experimentally investigated. The effects of the nanoparticle concentration, Reynolds number, nozzle-to-plate distance, fluid temperature, and nanoparticle diameter on the heat transfer performances of the jet impingement of nanofluids are discussed. The experimental results show that the suspended nanoparticles remarkably increase the convective heat transfer coefficient of the base fluid. The convective heat transfer coefficient of Cu–water nanofluid with the volume fraction of 3.0% has 52% higher than the pure water. The experiments also revealed that the suspended nanoparticles brought almost no extra addition of pressure drop in both submerged single jet impingement. In addition, by considering the effects of the suspended nanoparticles as well as the condition of impinging jet, a new heat transfer correlation of nanofluids for the submerged single jet impingement has been proposed. - Highlights: ► Cu–water nanofluids are introduced into submerged single jet impingement. ► The affecting parameters on the heat transfer performances of nanofluids are discussed. ► New heat transfer correlation of nanofluid for single jet impingement is proposed.

Flow transport and mixing induced by horizontal jets impinging on a vertical wall of the multi-compartment PANDA facility

International Nuclear Information System (INIS)

Paladino, Domenico; Zboray, Robert; Andreani, Michele; Dreier, Joerg

2010-01-01

In the frame of the OECD/NEA SETH project an experimental campaign has been carried out in the PANDA facility to investigate gas transport and mixing induced by a plume or a jet in the large-scale multi-compartment PANDA facility. The paper summarizes the results of the horizontal jet test series consisting of eight tests. Horizontal jets impinging on a vertical wall of one of the cylindrical PANDA containment vessels have been generated by changing various parameters, such as: type of injected fluid (steam or a mixture of steam and helium), fluid injection velocity, elevation (with respect to the containment vessel) of the injection exit, initial fluid composition in the vessels, and location of the vent line. The initial jet Froude number has been varied between 17 and 36 and in one of the test condensation occurred. The paper shows the effect of these parameters variation on the test evolution with respect to jet impingement location in the vertical curved wall and variation of impingement location as a function of buoyancy variation. Fluid mixing and stratification, characteristics of gas transport between the compartment and the effect of condensation on the overall phenomena evolution are analyzed in the paper.

Atmospheric H2O2 measurement: comparison of cold trap method with impinger bubbling method

Science.gov (United States)

Sakugawa, H.; Kaplan, I. R.

1987-01-01

Collection of atmospheric H2O2 was performed by a cold trap method using dry ice-acetone as the refrigerant. The air was drawn by a pump into a glass gas trap immersed in the dry ice-acetone slush in a dewar flask at a flow rate of 2.5 l min-1 for approximately 2 h. Collection efficiency was > 99% and negligible interferences by O3, SO2 or organic matter with the collected H2O2 in the trap were observed. This method was compared with the air impinger bubbling method which has been previously described (Kok et al., 1978a, b, Envir. Sci. Technol. 12, 1072-1080). The measured total peroxide (H2O2 + organic peroxide) values in a series of aim samples collected by the impinger bubbling method (0.06-3.7 ppb) were always higher than those obtained by the cold trap method (0.02-1.2 ppb). Laboratory experiments suggest that the difference in values between the two methods probably results from the aqueous phase generation of H2O2 and organic peroxide in the impinger solution by a reaction of atmospheric O3 with olefinic and aromatic compounds. If these O3-organic compound reactions which occur in the impinger also occur in aqueous droplets in the atmosphere, the process could be very important for aqueous phase generation of H2O2 in clouds and rainwater.

Direct Flame Impingement

Energy Technology Data Exchange (ETDEWEB)

None

2005-09-01

During the DFI process, high velocity flame jets impinge upon the material being heated, creating a high heat transfer rate. As a result, refractory walls and exhaust gases are cooler, which increases thermal efficiency and lowers NOx emissions. Because the jet nozzles are located a few inches from the load, furnace size can be reduced significantly.

Numerical Investigation of Jet Impingement Heat Transfer on a Flat plate

Directory of Open Access Journals (Sweden)

Asem Nabadavis

2016-12-01

Full Text Available The numerical investigation emphasizes on studying the heat transfer characteristics when a high velocity air jet impinges upon a flat plate having constant heat flux. Numerical analysis has been conducted by solving conservation equations of momentum, mass and energy with two equations based k- ε turbulence model to determine the wall temperature and Nu of the plate considering the flow to be incompressible. It was found from the investigation that the heat transfer rate increases with the increase of Reynolds number of the jet (Rej. It was also found that there is an optimum value for jet distance to nozzle diameter ratio (H/d for maximum heat transfer when all the other parameters were kept fixed. Similar results as above were found when two jets of air were used instead of one jet keeping the mass flow rate constant. For a two jets case it was also found that heat transfer rate over the surface increases when the jets are inclined outward compared to vertical and inward jets and also there exists an optimum angle of jet for maximum heat transfer. Further investigation was carried out for different jetto-jet separation distance for a twin jet impingement model where it was noted that heat transfer is more distributed in case of larger values of L and the rate of heat transfer increases as the separation between the jet increases till a certain point after which the rate of heat transfer decreases.

Shoulder Girdle Muscles Endurance in Subjects with and without Impingement Syndrome

Directory of Open Access Journals (Sweden)

Afsoun Nodehi-Moghadam

2011-07-01

Full Text Available Objective: Any minimal alteration in performance and coordination of scapular and glenohumeral muscles has the potential to lead to shoulder joint dysfunction. The impingement syndrome has been reported as is the most common diagnosis of shoulder pain. The purpose of this study was to determine whether endurance deficits could be detected in patients with shoulder impingement. Materials & Methods: By convenient sampling 15 patients with impingement syndrome at average of 45.3 years of age and 15 healthy persons (age 45.8 years through a case–control design participated in the study. Endurance of glenohumeral and scapulothoracic muscles were tested with a hand held dynamometer. Independent t–test was used to statistically analyze different groups. Results: Compared to non–impaired subjects, those with impingement syndrome demonstrated a significantly lower endurance of external rotation, scaption and scapular abduction and upward rotation movements (P<0.05. In impingement syndrome patients, the external–to–internal rotator muscles endurance ratio was significantly lower than the control group (P<0.05. Conclusion: The result of the study suggests that endurance deficit of rotator cuff and scapular upward rotator muscles may be an important aspect of the impingement syndrome. Shoulder girdle muscles endurance should be considered in evaluation and physical therapy of impingement syndrome patients.

Analysis of impingement impacts on Hudson River fish populations

International Nuclear Information System (INIS)

Barnthouse, L.W.; van Winkle, W.

1988-01-01

Impacts of impingement, expressed as reductions in year-class abundance, were calculated for six Hudson River fish populations. Estimates were made for the 1974 and 1975 year classes of white perch, striped bass, Atlantic tomcod, and American shad, and the 1974 year classes of alewife and blueback herring. The maximum estimated reductions in year-class abundance were less than 5% for all year classes except the 1974 and 1975 white perch year classes and the 1974 striped bass year class. Only for white perch were the estimates greater than 10% per year. For striped bass, the 146,000 fish from the 1974 year class that were killed by impingement could have produced 12,000-16,000 5-year-old fish or 270-300 10-year-olds. Also estimated were the reductions in mortality that could have been achieved had closed-cycle cooling systems been installed at one or more of three power plants (Bowline point, Indian Point, and Roseton) and had the screen-wash systems at Bowline Point and Indian Point been modified to improve the survival of impinged fish. Closed-cycle cooling at all three plants would have reduced impingement impacts on white perch, striped bass, and Atlantic tomcod by 75% or more; installation of closed-cycle cooling at Indian Point alone would have reduced impingement impacts on white perch and Atlantic tomcod by 50%-80%. Modified traveling screens would have been less effective than closed-cycle cooling, but still would have reduced impingement impacts on white perch by roughly 20%. 23 refs., 1 fig., 3 tabs

Trochanteric impingement: is it a source of pain after THR?

Directory of Open Access Journals (Sweden)

Mark J. Isaacson, DO

2015-09-01

Full Text Available While uncommon, trochanteric-pelvic impingement may lead to significant lateral hip pain. We defined “impingement distance” as the radiographic distance from the medial aspect of the greater trochanter and the corresponding lateral edge of the acetabular bone or component and compared this to the contralateral normal hip. We present two painful total hip replacement (THR cases, each featuring a patient with severe lateral hip pain when walking and sitting. Both patients had diminished femoral offset and trochanteric-pelvic clearance, compared to the contralateral normal hip. The impingement distance was increased an average of 10 mm with the exchange to a longer femoral head. Both patients had immediate and complete pain relief with operative treatment to increase the impingement distance.

Shouldering the blame for impingement: the rotator cuff continuum ...

African Journals Online (AJOL)

The aim of this article was to summarise recent research on shoulder impingement and rotator cuff pathology. A continuum model of rotator cuff pathology is described, and the challenges of accurate clinical diagnosis, imaging and best management discussed. Keywords: shoulder impingement syndrome, subacromial ...

Study on the characteristics of the impingement erosion-corrosion for Cu-Ni Alloy sprayed coating(I)

International Nuclear Information System (INIS)

Lee, Sang Yeol; Lim, Uh Joh; Yun, Byoung Du

1998-01-01

Impingement erosion-corrosion test and electrochemical corrosion test in tap water(5000Ω-cm) and seawater(25Ω-cm). Thermal spraying coated Cu-Ni alloy on the carbon steel was carried out. The impingement erosion-corrosion behavior and electrochemical corrosion characteristics of the substrate(SS41) and Cu-Ni thermal spray coating were investigated. The erosion-corrosion control efficiency of Cu-Ni coating to substrate was also estimated quantitatively. Main results obtained are as follows : 1) Under the flow velocity of 13m/s, impingement erosion-corrosion of Cu-Ni coating is under the control of electrochemical corrosion factor rather than that of mechanical erosion. 2) The corrosion potential of Cu-Ni coating becomes more noble than that of substrate, and the current density of Cu-Ni coating under the corrosion potential is drained lowly than that of substrate. 3) The erosion-corrosion control efficiency of Cu-Ni coating to substrate is excellent in the tap water of high specific resistance solution, but it becomes dull in the seawater of low specific resistance. 4) The corrosion control efficiency of Cu-Ni coating to substrate in the seawater appears to be higher than that in the tap water

Effect of applied potential on passivation and erosion–corrosion of a Fe-based amorphous metallic coating under slurry impingement

International Nuclear Information System (INIS)

Zheng, Z.B.; Zheng, Y.G.; Sun, W.H.; Wang, J.Q.

2014-01-01

Highlights: • The passive current density of coating increases with the increasing potential. • Preferential dissolution of high-valence oxides happens at high applied potential. • More chlorides exist in the passive film at high film formation potential. • Critical flow velocity under impingement is related to resistance of passive film. - Abstract: The passive behaviour and erosion–corrosion behaviour of a HVOF sprayed Fe-based amorphous metallic coating have been investigated in 3.5 wt.% NaCl solution by using potentiostatic polarisation, X-ray photoelectron spectroscopy and Mott–Schottky analysis. The fact that passive current density increased with rising potential might result from the preferential dissolution of high-valence oxides and the existence of more chlorides at a higher potential. The critical flow velocity decreased with rising potential because of the lower resistance of passive film at a higher potential. The reason why passive current density changed under jet impingement was discussed by a simple formula

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

Rotational effects on impingement cooling

Science.gov (United States)

Epstein, A. H.; Kerrebrock, J. L.; Koo, J. J.; Preiser, U. Z.

1987-01-01

The present consideration of rotation effects on heat transfer in a radially exhausted, impingement-cooled turbine blade model gives attention to experimental results for Reynolds and Rossby numbers and blade/coolant temperature ratio values that are representative of small gas turbine engines. On the basis of a model that encompasses the effects of Coriolis force and buoyancy on heat transfer, bouyancy is identified as the cause of an average Nusselt number that is 20-30 percent lower than expected from previous nonrotating data. A heuristic model is proposed which predicts that the impingement jets nearest the blade roots should deflect inward, due to a centripetal force generated by their tangential velocity counter to the blade motion. Potentially serious thermal stresses must be anticipated from rotation effects in the course of blade design.

Active control of supersonic impingement tones using steady and pulsed microjets

Energy Technology Data Exchange (ETDEWEB)

Choi, J.J.; Anaswamy, A.M. [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge (United States); Lou, H. [Department of Mechanical Engineering, FAMU - FSU, College of Engineering, Tallahassee, FL (United States); Alvi, F.S.

2006-12-15

In recent years, it has been demonstrated that direct microjet injection into the shear layer of the main jet disrupts the feedback loop inherent in high speed impinging jet flows, thereby significantly reducing the adverse effects. The amount of noise reduced by microjet actuation is known to be dependent on nozzle operating conditions. In this paper, two active control strategies using microjets are suggested to maintain a uniform, reliable, and optimal reduction of these tones over the entire range of operating conditions. In the first method, a quasi-closed loop control strategy is proposed using steady microjet injection and the proper orthogonal decomposition (POD) algorithm. The most energetic spatial mode of the unsteady pressure along the nozzle diameter is captured using the POD, which in turn is used to determine the distribution of microjet intensity along the nozzle exit. Preliminary experimental results from a STOVL supersonic jet facility at Mach 1.5 show that the quasi-closed loop control strategy, in some cases, provides an additional 8-10 dB reduction compared to axisymmetric injection at the desired operating conditions. The second method consists of a pulsed microjet injection, motivated by the need to further improve the noise suppression. It was observed that the pulsed microjet was able to bring about the same noise reduction as steady injection using approximately 40% of the corresponding mass flow rate of the steady microjet case. Moreover, as the duty cycle increased, the performance of pulsed injection was further enhanced and was observed to completely eliminate the impinging tones at all operating conditions. (orig.)

Practicality of profile-wire screen in reducing entrainment and impingement

International Nuclear Information System (INIS)

Hanson, B.N.; Bason, W.H.; Beitz, B.E.; Charles, K.E.

1978-01-01

Experimental studies indicated that 1.01-mm slot profile-wire well screen operated at an intake velocity of 15.24 cm/s virtually eliminated impingement of fishes larger than 15 mm fork length (FL). Intake velocities as high as 53.34 cm/s produced low impingement. Tests of fish less than 40 mm FL held near a functioning intake (15.24 cm/s) for as long as 3 hr yielded no impingement or stress. Many striped bass between 8 and 17 mm FL were capable of resisting impingement at more than 30.48 cm/s velocity for longer than 30 min; larger specimens (12 to 17 mm) showed excellent ability to escape when impinged. The screen excluded virtually all striped bass eggs from the cooling water. Preliminary egg mortality studies indicate that at least 95% survival can be expected at an approach velocity of 15.24 cm/s and impingement durations up to 2 min. Fouling studies showed that screens were highly resistant to clogging, essentially self-cleaning in a current, and easily backwashed. In-situ studies in the Chesapeake and Delaware Canal have shown that a 61.0- x 76.2-cm, 1.01-mm-slot screen is capable of providing its designed capacity for weeks without backwashing or cleaning. Biofouling proved to be the greatest operational problem. Entrainment samples from the in-situ intake have shown significant reductions in organisms/m 3 of filtered versus ambient water

Computer program for compressible flow network analysis

Science.gov (United States)

Wilton, M. E.; Murtaugh, J. P.

1973-01-01

Program solves problem of an arbitrarily connected one dimensional compressible flow network with pumping in the channels and momentum balancing at flow junctions. Program includes pressure drop calculations for impingement flow and flow through pin fin arrangements, as currently found in many air cooled turbine bucket and vane cooling configurations.

Experimental studies on transient water-steam impinging jet

International Nuclear Information System (INIS)

Kitade, Kozo; Nakatogawa, Tetsundo; Nishikawa, Hideo; Kawanishi, Kohei; Tsuruto, Chuichi.

1980-01-01

Blowdown experiments were carried out in order to clarify pipe reaction forces and jet forces at hypothetical pipe break accident in PWR. The experiments were carried out at the initial pressure of about 70 and 150 kg/cm 2 .G with subcooling temperature of 13 -- 41 0 C. The reaction force has a maximum value just after the rupture in such a manner to attain abruptly to a peak and gradually decreases after that time in proportion to the inner pressure of the pipe. A plane board was used as a target, on which two-phase flow jet impinged vertically. A distribution of pressure on the target is most wide just after break. On the other hand, the pressure has a maximum value after a short period of time from the rupture. (author)

ARTHROSCOPIC TREATMENT OF ANTERIOR IMPINGEMENT IN THE ANKLE

Directory of Open Access Journals (Sweden)

Martin Mikek

2004-12-01

Full Text Available Background. Anterior soft tissue impingement is a common cause of chronic pain in the ankle. The preferred method of operative treatment is an arthroscopic excision of hypertrophic fibrous and synovial tissue in the anterior part of the ankle joint.Methods. We present the results of arthroscopic treatment of anterior ankle impingement in group of 14 patients.Results. Subjective improvement after the procedure was observed in all patients and 13 of them (93% were without any symptoms after the operation. One patient reported of intermittent pain, especially when walking on uneven grounds.Conclusions. We conclude that arthroscopic excision of hypertrophic synovial tissue in the anterior part of the ankle which causes the symptoms of impingement is a minimally invasive procedure that is both safe and reliable. When used for appropriate indications, an improvement can be expected in over 90% of patients.

Clinical radiation diagnostics of shoulder joint impingement syndrome

International Nuclear Information System (INIS)

Litvin, Yu.P.; Logvinenko, V.V.

2014-01-01

46 patients about an impingement are investigated by a syndrome of a humeral joint. Among them men was 28 (60,9 %) the person, women 18 (39,1 %). Middle age of the surveyed has made 52,6 ± 2,0 year. The traditional roentgenography is executed to all patients, a spiral computer tomography - 5 (10,9 %), an ultrasonography - 44 (95,7 %), a magnetic resonance imaging - 11 (23,9 %). Operative treatment is spent 16 (34,8 %) by the patient. Direct radial symptoms are what specify an impingement of a syndrome of a humeral joint in the reasons, indirect - symptoms of an inflammation both degenerate and dystrophic changes of structures of area of a humeral joint which are involved in pathological process. The best results are given by complex radial research at which it is possible to find out direct and indirect symptoms a syndrome impingement

Impact of impingement on the Hudson River white perch population

International Nuclear Information System (INIS)

Barnthouse, L.W.; Van Winkle, W.

1980-01-01

The impact of power plant impingement on the 1974 and 1975 year classes of the Hudson River white perch population is assessed using a simple model derived from Ricker's theory of fisheries dynamics. The impact of impingement is expressed in the model as the conditional mortality rate, rather than as the more commonly used exploitation rate. Since the calculated impact is sensitive to errors in the estimation of population size and total mortality, ranges of probable values of these quantities are used to compute upper and lower bounds on the fractional reduction in abundance of each year class. Best estimates of abundance and mortality are used to compute the conditional impingement mortality rate separately for each plant and month. The results are used to assess the relative impacts of white perch impingement at six Hudson River power plants and to identify the seasons during which the impact is highest

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.)

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.

Open and Arthroscopic Surgical Treatment of Femoroacetabular Impingement

Directory of Open Access Journals (Sweden)

Benjamin D. Kuhns

2015-12-01

Full Text Available Femoroacetabular impingement (FAI is a common cause of hip pain, and when indicated, can be successfully managed through open surgery or hip arthroscopy. The goal of this review is to describe the different approaches to the surgical treatment of FAI. We present the indications, surgical technique, rehabilitation, and complications associated with (1 open hip dislocation, (2 reverse peri-acetabular osteotomy, (3 the direct anterior mini-open approach, and (4 arthroscopic surgery for femoroacetabular impingement.

Comparison of Endotoxin Exposure Assessment by Bioaerosol Impinger and Filter-Sampling Methods

OpenAIRE

Duchaine, Caroline; Thorne, Peter S.; Mériaux, Anne; Grimard, Yan; Whitten, Paul; Cormier, Yvon

2001-01-01

Environmental assessment data collected in two prior occupational hygiene studies of swine barns and sawmills allowed the comparison of concurrent, triplicate, side-by-side endotoxin measurements using air sampling filters and bioaerosol impingers. Endotoxin concentrations in impinger solutions and filter eluates were assayed using the Limulus amebocyte lysate assay. In sawmills, impinger sampling yielded significantly higher endotoxin concentration measurements and lower variances than filte...

Boundary layer theory approach to the concentration layer adjacent to the ceiling wall of a hydrogen leakage: Axisymmetric impinging and far regions

Energy Technology Data Exchange (ETDEWEB)

El-Amin, M.F.; Kanayama, H. [Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

2009-02-15

As hydrogen leaks into a partially open space with a ceiling wall, a boundary layer of hydrogen can be constructed under that wall due to the impingement on the wall and the buoyancy force. The resulting boundary layer can be divided into two regions, namely the stagnation-point region and the far region. When the geometry of the source of the hydrogen leak is circular, such as a pinhole or an o-ring, the behavior of leakage flow will be axisymmetric due to the resulting radial jet. In contrast, when the geometry of the source of the hydrogen leak is planar, such as a crack, the behavior of leakage flow will be planar due to the resulting planar jet. Previously, we studied the planar case in the context of both the stagnation-point flow region [El-Amin MF, Kanayama H. Boundary layer theory approach to the concentration layer adjacent to a ceiling wall at impinging region of a hydrogen leakage. Int J Hydrogen Energy 2008; 33(21): 6393-00] and the far region [El-Amin MF, Inoue M, Kanayama H. Boundary layer theory approach to the concentration layer adjacent to a ceiling wall of a hydrogen leakage: far region. Int J Hydrogen Energy 2008; 33(24):7642-7]. This paper is concerned with both the stagnation-point flow region and the far region of the axisymmetric concentration boundary layer adjacent to a ceiling wall. Flow in the stagnation-point region is treated as Hiemenz flow, while it is treated as Blasius flow in the far region. The current results are compared with the planar cases [El-Amin MF, Kanayama H. Boundary layer theory approach to the concentration layer adjacent to a ceiling wall at impinging region of a hydrogen leakage. Int J Hydrogen Energy 2008; 33(21): 6393-00; El-Amin MF, Inoue M, Kanayama H. Boundary layer theory approach to the concentration layer adjacent to a ceiling wall of a hydrogen leakage: far region. Int J Hydrogen Energy 2008; 33(24):7642-7] for both stagnation-point flow and far regions. Both momentum and concentration boundary layer

MR imaging of nerve root impingement in the lumbar spine

International Nuclear Information System (INIS)

Teresi, L.M.; Bradley, W.G. Jr.; Bloze, A.E.; Davis, S.J.; Amster, J.; Berger, P.E.

1990-01-01

This paper determines the relationship between MR imaging findings of nerve root impingement, presenting symptoms, and physical examination findings, and physiologic data (DSEP and EMG) in a population of patients presented with classic radicular symptoms. Fifty-eight patients presenting with classic radicular pain were studied with MR imaging, DSER, and EMG, MR imaging was performed with a GE Signa imaging system with use of T1- and T2-weighted sequences and 5-mm-thick sections. Nerve root impingement in the subarticular recess (the root exiting the next lowest level) was distinguished from nerve root impingement in the superior intervertebral foramen (the root exiting the same level)

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.

A study on the velocity characteristics of the spray formed by two impinging jets

International Nuclear Information System (INIS)

Choo, Yeon Jun; Seo, Kwi Hyun; Kang, Bo Seon

2001-01-01

In this study, the velocity characteristics of liquid elements formed by two impinging jets is analysed using double pulse image capturing technique. For the droplets formed by low speed impinging jets, the droplet velocities are higher with smaller azimuthal and impingement angle. The maximum droplet velocities are about 25% lower than jet velocity. With an increase of azimuthal angle, the shedding angles increases but remains lower than azimuthal angle. The velocities of ligaments formed by high speed impinging jets gradually decreases with an increase of azimuthal angle. The maximum ligament velocities are about 40% lower than jet velocity. Higher impingement angles produce lower ligament velocities. The shedding angles of ligament almost increases with the same value of azimuthal angle, which implies that the moving direction of ligaments is radial from the origin as the impingement point

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.

Trailing edge cooling using angled impingement on surface enhanced with cast chevron arrangements

Science.gov (United States)

Lee, Ching-Pang; Heneveld, Benjamin E.; Brown, Glenn E.; Klinger, Jill

2015-05-26

A gas turbine engine component, including: a pressure side (12) having an interior surface (34); a suction side (14) having an interior surface (36); a trailing edge portion (30); and a plurality of suction side and pressure side impingement orifices (24) disposed in the trailing edge portion (30). Each suction side impingement orifice is configured to direct an impingement jet (48) at an acute angle (52) onto a target area (60) that encompasses a tip (140) of a chevron (122) within a chevron arrangement (120) formed in the suction side interior surface. Each pressure side impingement orifice is configured to direct an impingement jet at an acute angle onto an elongated target area that encompasses a tip of a chevron within a chevron arrangement formed in the pressure side interior surface.

The jet impingement phase of molten core-concrete interactions

International Nuclear Information System (INIS)

Sienicki, J.J.; Spencer, B.W.

1986-01-01

Scoping calculations have been carried out demonstrating that a significant and abrupt reduction in the corium temperature may be realized when molten corium drains as a jet from a localized breach in the RPV lower head to impinge upon the concrete basemat. The temperature decrease may range from a value of ∼170 K (∼140 K) for limestone (basaltic) aggregate concrete to a value approaching the initial corium superheat depending upon whether the forced convection impingement heat flux is assumed to be controlled by either thermal conduction across a slag film layer or the temperature boundary condition represented by a corium crust. The magnitude of the temperature reduction remains significant as the initial corium temperature, impinging corium mass, and initial localized breach size are varied over their range of potential values

Burnout in a high heat-flux boiling system with an impinging jet

International Nuclear Information System (INIS)

Monde, M.; Katto, Y.

1978-01-01

An experimental study has been made on the fully-developed nucleate boiling at atmospheric pressure in a simple forced-convection boiling system, which consists of a heated flat surface and a small, high-speed jet of water or of freon-113 impinging on the heated surface. A generalized correlation for burnout heat flux data, that is applied to either water or freon-113 is successfully evolved, and it is shown that surface tension has an important role for the onset of burnout phenomenon, not only in the ordinary pool boiling, but also in the present boiling system with a forced flow. (author)

Bone tumor mimickers: A pictorial essay

International Nuclear Information System (INIS)

Mhuircheartaigh, Jennifer Ni; Lin, Yu-Ching; Wu, Jim S

2014-01-01

Focal lesions in bone are very common and many of these lesions are not bone tumors. These bone tumor mimickers can include numerous normal anatomic variants and non-neoplastic processes. Many of these tumor mimickers can be left alone, while others can be due to a significant disease process. It is important for the radiologist and clinician to be aware of these bone tumor mimickers and understand the characteristic features which allow discrimination between them and true neoplasms in order to avoid unnecessary additional workup. Knowing which lesions to leave alone or which ones require workup can prevent misdiagnosis and reduce patient anxiety

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

Modelling of soft impingement during solidification

Indian Academy of Sciences (India)

TECS

soft impingement problem and related to shape instability by constitutional supercooling theory. This analysis ... the context of the stir casting process, it has been pointed ... This transformation when applied to Fick's second law gives the ...

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.

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

International Nuclear Information System (INIS)

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

Comparative analysis of arthroscopic debridement in osseous versus soft tissue anterior ankle impingement.

Science.gov (United States)

Devgan, Ashish; Rohilla, Rajesh; Tanwar, Milind; Jain, Aditya; Siwach, Karan; Devgan, Radika

2016-01-01

Arthroscopic debridement has been a gold standard procedure for anterior ankle impingement, both in cases of osseous and soft tissue impingement. There is sparse literature on comparative outcome with respect to functional results between the two types of impingement post-arthroscopic debridement. Our study included 14 patients diagnosed as cases of anterior ankle impingement on the basis of clinical and radiological examination. They were segregated into two groups (on the basis of cause of impingement (osseous versus soft tissue)). Both groups were treated by arthroscopic debridement. Primary outcome was patient satisfaction, which was assessed by Likert scale and clinical outcomes were measured using AOFAS ankle-hind foot scale, VAS score, range of motion and time to return to pre-injury activity level in both groups. Mean follow-up was of 15 months where eleven patients reported an excellent recovery, two patients had good recovery while one patient reported poor outcome. Mean AOFAS ankle hind foot scale improved from 50.5 preoperatively to 85.71 postoperatively (statistically significant; p value - 0.0001). Mean Likert scale value post-operative was 4.21. VAS score showed significant improvement in patients of both the groups. Range of motion was slightly better in soft tissue impingement type with a relatively shorter time to return to sports or preinjury activity level as compared to osseous impingement group. The patients in both the groups had comparable outcomes with no statistically significant difference with regard to patient satisfaction and clinical outcome.

Shoulder impingement syndrome: diagnostic accuracy of magnetic resonance imaging and radiographic signs

International Nuclear Information System (INIS)

Williamson, M.P.; Chandnani, V.P.; Baird, D.E.; Deberardino, T.M.; Swenson, G.W.; Hansen, M.F.

1994-01-01

Shoulder impingement syndrome is commonly encountered in orthopaedics. In a blinded retrospective study, magnetic resonance imaging and roentgenographic signs in 41 patients with clinical signs of impingement syndrome were compared with 40 control patients. Statistically significant differences between the groups included the absence of subacromial fat, as well as the presence of a supraspinatus tear, subacromial osteophytes, and a decreased coracohumeral distance. Other signs reported to occur in patients with impingement syndrome did not vary significantly in the population studied. 20 refs., 12 figs

Performance Analysis of a Multiple Micro-Jet Impingements Cooling Model

Directory of Open Access Journals (Sweden)

A. Husain

2016-06-01

Full Text Available The present study investigates the thermal performance of a multiple micro-jet impingements model for electronics cooling. The fluid flow and heat transport characteristics were investigated for steady incompressible laminar flow by solving three-dimensional (3D Navier-Stokes equations. Several parallel and staggered micro-jet configurations (ie. inline 2 Å~ 2, 3 Å~ 3 and 4 Å~ 4 jets, and staggered five-jet and 13-jet arrays with the jet diameter to the channel height ratios from 0.25–0.5 were analyzed at various flow rates for the maximum temperature rise, pressure drop, heat-transfer coefficient, thermal resistance, and pumping power characteristics. The parametric investigation was carried out based on the number of jets and the jet diameters at various mass flow rates and jet Reynolds numbers. Temperature uniformity and coefficient of performance were evaluated to find out the trade-off among the various designs investigated in the present study. The maximum temperature rise and the pressure drop decreased with an increase in the number of jets except in the case of staggered five-jet array. A higher temperature uniformity was observed at higher flow rates with a decrease in the coefficient of performance. The performance parameters, such as thermal resistance and pumping power, showed a conflicting nature with respect to design variables (viz. jet diameter to stand-off ratio and interjet spacing or number of jets at various Reynolds numbers within the laminar regime.

The entrainment of air by water jet impinging on a free surface

Energy Technology Data Exchange (ETDEWEB)

Soh, Wee King [University of Wollongong, School of Mechanical, Materials and Mechatronics Engineering, Northfields Ave, NSW (Australia); Khoo, Boo Cheong [National University of Singapore, Department of Mechanical and Production Engineering, 10 Kent Ridge Crescent (Singapore); Yuen, W.Y. Daniel [BlueScope Steel Research, Port Kembla, NSW (Australia)

2005-09-01

High-speed cine and video photographs were used to capture the flow patterns of a column of water jet impinging into a pool of water. The impact results in air entrainment into water in the form of a void with no mixing between the water in the jet and the surrounding water. Conservation of fluid momentum shows that the rate of increase of the height of the air void depends on the drag coefficient of the jet front. By neglecting the frictional losses, the application of energy conservation yields an expression that relates the maximum height of the air void with the properties of the water jet. (orig.)

Physics of Particle Entrainment Under the Influence of an Impinging Jet

Science.gov (United States)

2008-12-01

Approved for public release; distribution unlimited 1 PHYSICS OF PARTICLE ENTRAINMENT UNDER THE INFLUENCE OF AN IMPINGING JET Robert Haehnel...Ing. Wesen. Heft 361). Phares, D.J., Smedley , G.T. and Flagan, R.C. (2000) "The wall shear stress produced by the normal impingement of a jet on a

Reliability of impingement sampling designs: An example from the Indian Point station

International Nuclear Information System (INIS)

Mattson, M.T.; Waxman, J.B.; Watson, D.A.

1988-01-01

A 4-year data base (1976-1979) of daily fish impingement counts at the Indian Point electric power station on the Hudson River was used to compare the precision and reliability of three random-sampling designs: (1) simple random, (2) seasonally stratified, and (3) empirically stratified. The precision of daily impingement estimates improved logarithmically for each design as more days in the year were sampled. Simple random sampling was the least, and empirically stratified sampling was the most precise design, and the difference in precision between the two stratified designs was small. Computer-simulated sampling was used to estimate the reliability of the two stratified-random-sampling designs. A seasonally stratified sampling design was selected as the most appropriate reduced-sampling program for Indian Point station because: (1) reasonably precise and reliable impingement estimates were obtained using this design for all species combined and for eight common Hudson River fish by sampling only 30% of the days in a year (110 d); and (2) seasonal strata may be more precise and reliable than empirical strata if future changes in annual impingement patterns occur. The seasonally stratified design applied to the 1976-1983 Indian Point impingement data showed that selection of sampling dates based on daily species-specific impingement variability gave results that were more precise, but not more consistently reliable, than sampling allocations based on the variability of all fish species combined. 14 refs., 1 fig., 6 tabs

Diagnostic imaging of shoulder impingement

International Nuclear Information System (INIS)

Merl, T.; Weinhardt, H.; Oettl, G.; Lenz, M.; Riel, K.A.

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 [de

Optimization of Dimples in Microchannel Heat Sink with Impinging Jets — Part A: Mathematical Model and the Influence of Dimple Radius

Science.gov (United States)

Ming, Tingzhen; Cai, Cunjin; Yang, Wei; Shen, Wenqing; Gan, Ting

2018-06-01

With increasing heat fluxes caused by electronic components, dimples have attracted wide attention by researchers and have been applied to microchannel heat sink in modern advanced cooling technologies. In this work, the combination of dimples, impinging jets and microchannel heat sink was proposed to improve the heat transfer performance on a cooling surface with a constant heat flux 500 W/cm2. A mathematical model was advanced for numerically analyzing the fluid flow and heat transfer characteristics of a microchannel heat sink with impinging jets and dimples (MHSIJD), and the velocity distribution, pressure drop, and thermal performance of MHSIJD were analyzed by varying the radii of dimples. The results showed that the combination of dimples and MHSIJ can achieve excellent heat transfer performance; for the MHSIJD model in this work, the maximum and average temperatures can be as low as 320 K and 305 K, respectively when mass flow rate is 30 g/s; when dimple radius is larger than 0.195 mm, both the heat transfer coefficient and the overall performance h/ΔP of MHSIJD are higher than those of MHSIJ.

The art and science of flow control - case studies using flow visualization methods

Science.gov (United States)

Alvi, F. S.; Cattafesta, L. N., III

2010-04-01

Active flow control (AFC) has been the focus of significant research in the last decade. This is mainly due to the potentially substantial benefits it affords. AFC applications range from the subsonic to the supersonic (and beyond) regime for both internal and external flows. These applications are wide and varied, such as controlling flow transition and separation over various external components of the aircraft to active management of separation and flow distortion in engine components and over turbine and compressor blades. High-speed AFC applications include control of flow oscillations in cavity flows, supersonic jet screech, impinging jets, and jet-noise control. In this paper we review some of our recent applications of AFC through a number of case studies that illustrate the typical benefits as well as limitations of present AFC methods. The case studies include subsonic and supersonic canonical flowfields such as separation control over airfoils, control of supersonic cavity flows and impinging jets. In addition, properties of zero-net mass-flux (ZNMF) actuators are also discussed as they represent one of the most widely studied actuators used for AFC. In keeping with the theme of this special issue, the flowfield properties and their response to actuation are examined through the use of various qualitative and quantitative flow visualization methods, such as smoke, shadowgraph, schlieren, planar-laser scattering, and Particle image velocimetry (PIV). The results presented here clearly illustrate the merits of using flow visualization to gain significant insight into the flow and its response to AFC.

Surgical criteria for femoroacetabular impingement syndrome

DEFF Research Database (Denmark)

Peters, Scott; Laing, Alisha; Emerson, Courtney

2017-01-01

BACKGROUND: The purpose of this review was to analyse and report criteria used for open and arthroscopic surgical treatment of femoroacetabular impingement syndrome (FAIS). METHODS: A librarian-assisted computer search of Medline, CINAHL and Embase for studies related to criterion for FAIS surgery...

Parametric Study of Swept Impinging Oblique Shock/Boundary Layer Interactions

Science.gov (United States)

Doehrmann, Adam; Threadgill, James; Little, Jesse

2017-11-01

Modern high-speed vehicles have increasingly complex 3D geometries featuring: surface curvature, variable aspect ratio inlet ducts and swept bodies. Such distortion to the flow field necessitates a further understanding of swept 3D Shock/Boundary Layer Interactions (SBLIs), where various regimes of spanwise interaction development have been observed. A parametric experimental study of swept oblique impinging SBLIs has been conducted comparing cylindrical and conical interaction structures to that of swept compression ramps in previous work. This investigation examines five shock generators with 2D deflection of θ = 12 .5° and varying degrees of sweep (ψ = 10 .0° , 15 .0° , 22 .5° , 30 .0° , 40 .0°), with an incoming turbulent flow at Mach 2.3 and 3.0. Parametric characterization of surface oil-flow visualizations has shown that the inception length of the interaction follows a similar trend to that seen in swept compression ramps as sweep is varied, namely that it increases as sweep approaches a critical angle. However, this criteria disagrees with direct observations of separation and reattachment angles. Similarities in mean pressures profiles have also been assessed and analyzed with respect to the onset of a cylindrical/conical interaction. Supported by the Air Force Office of Scientific Research (FA9550-15-1-0430).

Modeling and computation of heat exchanges in the configuration of an impinging jet on a hot plate

International Nuclear Information System (INIS)

Seiler, N.; Mimouni, S.; Simonin, O.; Gardin, P.; Seiler, J.M.

2003-01-01

The knowledge of the metal temperature history is essential, especially when strip leave the rolling mill, to get adequate final mechanical properties of steel. Some experiments have yet been carried out on the heat transfer associated with the impingement of a planar (1*9 mm 2 ) subcooled (5-16 K) water jet on a heated plate. Complete boiling curves were then obtained at different locations from the stagnation point and it was observed a phenomenon of 'shoulder of flux' in the transition boiling region near the impingement point. The aim of this work is to compute the heat flux transferred between a very hot plate and a subcooled liquid under a planar impinging jet to obtain the transient temperature distribution in the plate. To achieve this goal, a physical modelling of the phenomenon of 'shoulder of flux' has been carried out. This modelling is based on the assumption that the apparition of periodic bubble oscillations at the wall surface is due to the hydrodynamic fragmentation by the jet. The relation derived from this modelling is validated against experimental results from the literature obtained for a wide range of jet velocity, subcooling and jet diameter. This model is implemented in the new multiphase flow solver developed by EDF 'SATURNE polyphasique'. Numerical results are then compared to experimental heat fluxes obtained on previous experiments. (authors)

A computational study of highly viscous impinging jets

Energy Technology Data Exchange (ETDEWEB)

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

1998-11-01

Two commercially-available computational fluid dynamics codes, FIDAP (Fluent, Inc., Lebanon, NH) and FLOW-3D (Flow Science, Inc., Los Alamos, NM), were used to simulate the landing region of jets of highly viscous fluids impinging on flat surfaces. The volume-of-fluid method was combined with finite difference and finite element approaches to predict the jet behavior. Several computational models with varying degrees of physical realism were developed, and the results were compared with experimental observations. In experiments, the jet exhibited several complex behaviors. As soon as it exited the nozzle, the jet began to neck down and become narrower. When it impacted the solid surface, the jet developed an instability near the impact point and buckled to the side. This buckling became a spiraling motion, and the jet spiraled about the impact point. As the jet spiraled around, a cone-shaped pile was build up which eventually became unstable and slumped to the side. While all of these behaviors were occurring, air bubbles, or voids, were being entrapped in the fluid pool. The results obtained from the FLOW-3D models more closely matched the behavior of real jets than the results obtained from /the FIDAP models. Most of the FLOW-3D models predicted all of the significant jet behaviors observed in experiments: necking, buckling, spiraling, slumping, and void entrapment. All of the FIDAP models predicted that the jet would buckle relatively far from the point of impact, whereas the experimentally observed jet behavior indicates that the jets buckle much nearer the impact point. Furthermore, it was shown that FIDAP is incapable of incorporating heat transfer effects into the model, making it unsuitable for this work.

A computational study of highly viscous impinging jets

International Nuclear Information System (INIS)

Silva, M.W.

1998-11-01

Two commercially-available computational fluid dynamics codes, FIDAP (Fluent, Inc., Lebanon, NH) and FLOW-3D (Flow Science, Inc., Los Alamos, NM), were used to simulate the landing region of jets of highly viscous fluids impinging on flat surfaces. The volume-of-fluid method was combined with finite difference and finite element approaches to predict the jet behavior. Several computational models with varying degrees of physical realism were developed, and the results were compared with experimental observations. In experiments, the jet exhibited several complex behaviors. As soon as it exited the nozzle, the jet began to neck down and become narrower. When it impacted the solid surface, the jet developed an instability near the impact point and buckled to the side. This buckling became a spiraling motion, and the jet spiraled about the impact point. As the jet spiraled around, a cone-shaped pile was build up which eventually became unstable and slumped to the side. While all of these behaviors were occurring, air bubbles, or voids, were being entrapped in the fluid pool. The results obtained from the FLOW-3D models more closely matched the behavior of real jets than the results obtained from /the FIDAP models. Most of the FLOW-3D models predicted all of the significant jet behaviors observed in experiments: necking, buckling, spiraling, slumping, and void entrapment. All of the FIDAP models predicted that the jet would buckle relatively far from the point of impact, whereas the experimentally observed jet behavior indicates that the jets buckle much nearer the impact point. Furthermore, it was shown that FIDAP is incapable of incorporating heat transfer effects into the model, making it unsuitable for this work

Numerical modeling of normal turbulent plane jet impingement on solid wall

Energy Technology Data Exchange (ETDEWEB)

Guo, C.Y.; Maxwell, W.H.C.

1984-10-01

Attention is given to a numerical turbulence model for the impingement of a well developed normal plane jet on a solid wall, by means of which it is possible to express different jet impingement geometries in terms of different boundary conditions. Examples of these jets include those issuing from VTOL aircraft, chemical combustors, etc. The two-equation, turbulent kinetic energy-turbulent dissipation rate model is combined with the continuity equation and the transport equation of vorticity, using an iterative finite difference technique in the computations. Peak levels of turbulent kinetic energy occur not only in the impingement zone, but also in the intermingling zone between the edges of the free jet and the wall jet. 20 references.

Entrainment and impingement of aquatic fauna at cooling water system of Madras Atomic Power Station (MAPS)

International Nuclear Information System (INIS)

Barath Kumar, S.; Das, N.P.I.; Satpathy, K.K.

2015-01-01

Marine organisms get impinged to the intake screens of Madras Atomic Power Station (MAPS) due to the suction force of the cooling water system of the power plant. The present work has studied the loss of aquatic organism at MAPS due to impingement at cooling water screens. In total 67 species of marine faunas impinged on the water intake screens of MAPS during the study. The proportion of fish, shrimp, crab, jellyfish and others, with respect to the total biomass of impinged organisms are 1.59 % (33 species), 0.30% (9), 2.77 % (16), 95.10% (3) and 0.24% (4), respectively. Jellyfishes were observed to be the largest entrained group covering around 44.85% of individual and constituting almost 94.82 % of biomass recorded during the study period and sea nettle jelly (Chrysaora quinquecirrha) was impinged with highest frequency. The diel study shows higher impingement occurred during night time, on full moon day and at low tides in contrast to their counterparts. Fishes accounts for 14.84 % of individual count and mere 1.67 % of biomass. Totally 33 number of fish species were observed. The highest impinged species were pony fishes (Secutor ruconius, Secutor insidiator, Photopectoralis bindus, Alepes kleinii and Leiognathus equulus) (21% occurrence). These few entrained fishes are mostly very small in size and have less commercial value. The total loss of marine fauna by impingement during study period was estimated to be 4779 (or 463.46 kg). The present data when compared with the impingement data from other coastal power plants, shows that the impinged fish biomass at MAPS cooling water system is much less than the other temperate and tropical power plants. (author)

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.

IMPINGEMENT COOLING OF A SEMI-CIRCULAR CONCAVE CHANNEL BY 2D AIR-JET

Directory of Open Access Journals (Sweden)

Serhan KÜÇÜKA

1998-01-01

Full Text Available This study provides a numerical solution to the flow in a cylindrical cavity of which the upper wall contains a twodimensional slot. The air injected through the slot impinges and diffuses laterally on the lower wall. The jet enfluxed through the slot is assumed to have uniform velocity and temperature, and the temperature at the lower wall is kept constant. The resulting Navier-Stokes equations are solved by transforming simpler algorithm into a form useably in cylindrical co-ordinate system. The effect of cavity curvature, and the height ratio on velocity and pressure distribution is analyzed. The jet Reynolds number ranged from 100 to 1500 in the analysis.

Acromion types and role of corticosteroid with shoulder impingement syndrome

International Nuclear Information System (INIS)

Akram, M.; Gillani, S.F.U.S.; Awais, S.M.

2016-01-01

To determine the association between shoulder impingement and morphological characteristics of acromion and the role of sub-acromial injection of methylprednisolone in the short-term treatment for relieving pain and improve functional disability of these patients. Study Design: A descriptive study. Place and Duration of Study: Department of Orthopedic Surgery and Traumatology Unit-I (DOST-I), Mayo Hospital, Lahore, between November 2013 to June 2014. Methodology: All patients presented in OPD with shoulder pain were included as subjects and evaluated by clinical test and categorised using X-ray scapula Y-view. Patients with impingement syndrome were correlated with Bigliani types and offered intra-lesional injection into sub-acromial space with 2ml of xylocaine 2% and 40 mg of methylprednisolone using 22 gauge needle. The effectiveness was assessed in terms of relieving pain and good functional outcomes; and rotator cuff tear was clinically assessed among impingement positive patient. The pain was assessed using visual analogue score before and after the administration of the injection. Demographic variables for frequencies and their associations were analysed using SPSS version 20.0. Significance level was p<0.05. Among the 101 cases, there was no case of tear of rotator cuff tendon on clinical assessment. Majority of the patients (58.4%) were females with mean age of 31.38 +-1.13 years. Majority 57 (56.4%) of the patients had acromion type II (curved), which was the most common cause of shoulder impingement. Most had moderate pain. Thirty-four patients required intralesional steroid, which relieved the pain in 31 of them. Conclusion: Shoulder impingement syndrome without tear of rotator cuff tendon was found in younger age group between 40 to 45 years, which was relieved by intralesional corticosteroid administration. These patients had type II (curved) acromion, according to Bigliani classification. (author)

An experimental study on impingement wastage of Mod 9Cr 1Mo steel due to sodium water reaction

Energy Technology Data Exchange (ETDEWEB)

Kishore, S., E-mail: skishore@igcar.gov.in [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Ashok Kumar, A.; Chandramouli, S.; Nashine, B.K.; Rajan, K.K.; Kalyanasundaram, P.; Chetal, S.C. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Sodium heated steam generators are crucial components of fast breeder reactors. Black-Right-Pointing-Pointer A leak in steam generator tube will cause sodium water reaction that damages the tubes. Black-Right-Pointing-Pointer Experimental study was conducted to quantify the extent of damage on Mod 9Cr 1Mo tube due to a water leak. - Abstract: Sodium heated steam generator (SG) is a crucial component in the heat transport system of a fast breeder reactor (FBR). In case, one of its water/steam carrying tubes becomes defective, water/steam leaks into sodium, flowing in the shell side, causing sodium-water reaction, which is highly exothermic and producing corrosive NaOH. The reaction jet originating from a leaking tube may impinge on its adjacent tube, resulting in damage of the tube. Impingement wastage refers to this kind of damage, occurring to a tube of sodium heated SG, owing to a small water/steam leak from a neighboring tube. Extensive research works have been conducted all over the world to study various aspects of this phenomenon. Experimental studies were carried out in Indira Gandhi Centre for Atomic Research (IGCAR) to understand the effect of impingement wastage on Mod 9Cr 1Mo, which is the tube material of prototype fast breeder reactor (PFBR) SG. This paper brings out the data and experience gained through the experiments.

Coherent Vortex Simulation (CVS) of vortex-dipoles impinging on a no-slip wall

Science.gov (United States)

Schneider, Kai; Farge, Marie

2004-11-01

Recently, we have introduced a new wavelet-based method, called Coherent Vortex Simulation (CVS), to compute turbulent flows (Flow, Turbulence and Combustion 66(4), 2001). The main idea is to split the flow into two orthogonal parts, a coherent flow and an incoherent background flow, using a nonlinear wavelet filtering of vorticity (Phys. Fluids, 11(8), 1999). As the coherent flow is responsible for the nonlinear dynamics, its evolution is deterministically computed in an adaptive wavelet basis, while the incoherent background flow being noise-like, structureless and decorrelated, its influence on the coherent flow is statistically modelled. Since the coherent part is described by only few wavelets, it is possible to reduce the computational cost, both in terms of memory requirement and cpu time. In order to take into account no-slip boundary conditions, we coupled the adaptive wavelet solver with a volume penalization technique (ACHA, 12, 2002). Here, we present applications of the CVS method to compute vortex dipoles impinging on a no-slip wall in a square container at different Reynolds numbers, which is a challenging test case for numerical methods. We observe the creation of strong vorticity gradients and the production of enstrophy when the dipole hits the wall. We show that the computational grid is dynamically adapted to the dipole evolution, since the wavelet nonlinear filter automatically refines the grid in regions of strong gradients. Note that during the computation only 5% out of 1024^2 wavelet coefficients are thus used.

Anterior ankle impingement after tendo-Achilles lengthening for long-standing equinus deformity in residual poliomyelitis.

Science.gov (United States)

Sung, Ki Hyuk; Chung, Chin Youb; Lee, Kyoung Min; Lee, Seung Yeol; Park, Moon Seok

2013-09-01

This study was performed to investigate anterior ankle impingement after tendo-Achilles lengthening for long-standing equinus deformity in patients with residual poliomyelitis and to investigate whether the severity of preoperative equinus deformity affected the occurrence of symptomatic anterior impingement. Twenty-seven consecutive patients (mean age, 43.8 ± 9.4 years) with residual poliomyelitis who underwent tendo-Achilles lengthening for equinus foot deformity were included. On lateral foot-ankle weight-bearing radiographs, the tibiocalcaneal angle, plantigrade angle, and McDermott grade were measured and the presence of anterior blocking spur was evaluated. Eleven patients (40.7%) had anterior ankle impingement on radiographic findings preoperatively and 24 patients (88.9%) at latest follow-up. There was a significant difference in McDermott grade between preoperative and latest follow-up (P poliomyelitis had anterior ankle impingement after tendo-Achilles lengthening for long-standing equinus deformity, and the presence of symptomatic anterior ankle impingement was significantly associated with the severity of the equinus deformity. Therefore, for residual poliomyelitis patients with severe long-standing equinus deformity, surgeons should consider the possibility of a subsequent anterior procedure for anterior impingement after tendo-Achilles lengthening. Level IV, retrospective case series.

Heat transfer and flow structure evaluation of a synthetic jet emanating from a planar heat sink

International Nuclear Information System (INIS)

Manning, Paul; Persoons, Tim; Murray, Darina

2014-01-01

Direct impinging synthetic jets are a proven method for heat transfer enhancement, and have been subject to extensive research. However, despite the vast amount of research into direct synthetic jet impingement, there has been little research investigating the effects of a synthetic jet emanating from a heated surface, this forms the basis of the current research investigation. Both single and multiple orifices are integrated into a planar heat sink forming a synthetic jet, thus allowing the heat transfer enhancement and flow structures to be assessed. The heat transfer analysis highlighted that the multiple orifice synthetic jet resulted in the greatest heat transfer enhancements. The flow structures responsible for these enhancements were identified using a combination of flow visualisation, thermal imaging and thermal boundary layer analysis. The flow structure analysis identified that the synthetic jets decreased the thermal boundary layer thickness resulting in a more effective convective heat transfer process. Flow visualisation revealed entrainment of local air adjacent to the heated surface; this occurred from vortex roll-up at the surface of the heat sink and from the highly sheared jet flow. Furthermore, a secondary entrainment was identified which created a surface impingement effect. It is proposed that all three flow features enhance the heat transfer characteristics of the system.

Methods on simple radiogaphy of impingement syndrome in shoulder joint

International Nuclear Information System (INIS)

Kweon, Dae Cheol; Kim, Moon Sun; Kim, Yong Seob; Chung, Kyung Mo

2000-01-01

To evaluation of patients who have shoulder impingement syndrome is by diagnostic radiography. Shoulder impingement is a problem which occurs in young, active individuals as well as older individuals. In fact, the pain is probably caused by repetitive stress placed on the shoulder joint either through recreational activities of your occupation. Impingement series approach to radiographic examination of the shoulder is take five projections. First anteroposterior oblique projection. Second standard anteroposterior projection. Third superoinferior axial projection. Fourth supraspinatus outlet projection offers a view of the outlet of the supraspinatus tendon unit as it passes under the coraacromial arch. Fifth anteroposterior 30 deg caudal projection will adequately demonstrate the anterior acromial spur or ossification in the coraacromial ligament and more reliable to demonstrate spurring of the anterior acromion than supraspinatus outlet projection. This decreased the need for additional radiographic veiws, reduces the patient's exposure to x-ray radiation and decreases use of film. This can lower the cost of the evaluation and improve patient satisfaction.=20

Methods on simple radiogaphy of impingement syndrome in shoulder joint

Energy Technology Data Exchange (ETDEWEB)

Kweon, Dae Cheol; Kim, Moon Sun; Kim, Yong Seob; Chung, Kyung Mo [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

2000-06-01

To evaluation of patients who have shoulder impingement syndrome is by diagnostic radiography. Shoulder impingement is a problem which occurs in young, active individuals as well as older individuals. In fact, the pain is probably caused by repetitive stress placed on the shoulder joint either through recreational activities of your occupation. Impingement series approach to radiographic examination of the shoulder is take five projections. First anteroposterior oblique projection. Second standard anteroposterior projection. Third superoinferior axial projection. Fourth supraspinatus outlet projection offers a view of the outlet of the supraspinatus tendon unit as it passes under the coraacromial arch. Fifth anteroposterior 30 deg caudal projection will adequately demonstrate the anterior acromial spur or ossification in the coraacromial ligament and more reliable to demonstrate spurring of the anterior acromion than supraspinatus outlet projection. This decreased the need for additional radiographic veiws, reduces the patient's exposure to x-ray radiation and decreases use of film. This can lower the cost of the evaluation and improve patient satisfaction.=20.

Development of a clinically relevant impingement test method for a mobile bearing lumbar total disc replacement.

Science.gov (United States)

Siskey, Ryan; Peck, Jonathan; Mehta, Hitesh; Kosydar, Allison; Kurtz, Steven; Hill, Genevieve

2016-09-01

Total disc arthroplasty is an alternative therapy to spinal fusion for the treatment of neck or low back pain and is hypothesized to reduce the risk of disease progression to the adjacent spinal levels. Radiographic and retrieval analyses of various total disc replacements (TDRs) have shown evidence of impingement damage. Impingement of TDRs can occur when the device reaches the limits of its functional range of motion, causing contact between peripheral regions of the device. Impingement can be associated with increased wear and mechanical damage; however, impingement conditions are not simulated in current standardized mechanical bench test methods. This study explored the test conditions necessary to apply clinically relevant impingement loading to a lumbar TDR in vitro. An experimental protocol was developed and evaluated using in vivo retrievals for qualitative and quantitative validation. Retrieval analysis was conducted on a set of 11 size 3 retrieved Charité devices using American Society for Testing and Materials F561 as a guide. The impingement range of motion was determined using a combination of modeling and experiments, and was used as an input in vitro testing. A 1-million cycle in vitro test was then conducted, and the in vitro samples were characterized using methods similar to the retreived devices. All in vitro tested samples exhibited impingement regions and damage patterns consistent with retrieved devices. Consistent with the retrievals, the impingement damage on the rim was a combination of abrasive wear and plastic deformation. Micro computed tomography (microCT) was used to quantitatively assess rim damage due to impingement. Rim penetration was statistically lower in the retrievals when compared with both in vitro groups. Rim elongation was comparable among all groups. The simulated-facet group had statistically greater angular rim deformations than the retrieval group and the no-facet group. Results demonstrate that clinically relevant

Computed tomography assessment of hip joints in asymptomatic individuals in relation to femoroacetabular impingement.

Science.gov (United States)

Kang, Alan C L; Gooding, Andrew J; Coates, Mark H; Goh, Tony D; Armour, Paul; Rietveld, John

2010-06-01

Femoroacetabular impingement has become a well-recognized entity predisposing to acetabular labral tears and chondral damage, and subsequently development of osteoarthritis of the hip joint. In the authors' experience, it is common to see bony abnormalities predisposing to femoroacetabular impingement in the contralateral asymptomatic hips in patients with unilateral femoroacetabular impingement. This study was undertaken to investigate the prevalence of bony abnormalities predisposing to femoroacetabular impingement in asymptomatic individuals without exposing study participants to unnecessary radiation. Cross-sectional study; Level of evidence, 4. Fifty individuals (100 hip joints), ranging from 15 to 40 years of age, who were seen at a local hospital between March and August 2008 with abdominal trauma or nonspecific abdominal pain in whom abdominal computed tomography was performed to aid diagnosis were prospectively studied. These patients were not known to have any history of hip-related problems. Raw data from the abdominal computed tomography scan, performed on a 64-slice multidetector computed tomography scanner, were reformatted using bone algorithm into several different planes. Several measurements and observations of the hip joints were made in relation to femoroacetabular impingement. The 100 hip joints from 50 patients with no history of hip problems demonstrated that 39% of the joints (31% of female, 48% of male joints) have at least 1 morphologic aspect predisposing to femoroacetabular impingement. The majority (66% to 100% ) of the findings were bilateral; 33% of female and 52% of male asymptomatic participants in our study had at least 1 predisposing factor for femoroacetabular impingement in 1 or both of their hip joints. Based on the data collected from this study, the acetabular crossover sign had a 71% sensitivity and 88% specificity for detecting acetabular retroversion. Nonquantitative assessment of the femoral head at the anterior

Sampling designs and methods for estimating fish-impingement losses at cooling-water intakes

International Nuclear Information System (INIS)

Murarka, I.P.; Bodeau, D.J.

1977-01-01

Several systems for estimating fish impingement at power plant cooling-water intakes are compared to determine the most statistically efficient sampling designs and methods. Compared to a simple random sampling scheme the stratified systematic random sampling scheme, the systematic random sampling scheme, and the stratified random sampling scheme yield higher efficiencies and better estimators for the parameters in two models of fish impingement as a time-series process. Mathematical results and illustrative examples of the applications of the sampling schemes to simulated and real data are given. Some sampling designs applicable to fish-impingement studies are presented in appendixes

Analysis of factors influencing the impingement of threadfin shad (Dorosoma pretenense) at power plants in the southeastern United States

International Nuclear Information System (INIS)

Loar, J.M.; Griffith, J.S.; Kumar, K.D.

1977-01-01

Data on intake design and location, plant operating procedures, water quality, numbers of fish impinged, and sampling procedures were analyzed for 27 fossil-fueled and 5 nuclear power plants located on inland waters in the southeastern United States. Small (less than 9 cm) clupeids, especially threadfin shad (Dorosoma pretenense), comprised the majority of the fish impinged at these facilities. The parameter that was most strongly associated with shad impingement was water temperature. Maximum impingement rates occurred during the winter when intake temperatures dropped below 10 0 C. Analyses of differences in impingement rates between plants failed to adequately demonstrate that the magnitude of impingement at a particular plant was the result of any site-specific characteristics associated with intake design or location. High approach velocities at the traveling screens did not necessarily result in high levels of impingement. Results obtained from inter-unit comparisons at several plants indicate that unit and screen differences do exist, but it is unclear from existing data whether or not such inter-unit differences determine the magnitude of impingement losses or merely affect the distribution of impinged fish at a given intake structure. Recommendations for monitoring fish impingement include the identification of impinged fish by species, collection of data on water temperatures and various plant operational parameters, periodic analyses of localized velocity regimes near the intake, and frequent estimates of the relative density of the fish population in the vicinity of the intake

MR imaging in the diagnosis of impingement syndrome

International Nuclear Information System (INIS)

Seeger, L.L.; Gold, R.H.; Bassett, L.W.; Ellman, H.

1986-01-01

The impingement syndrome is entrapment of the supraspinatus tendon by either the acromion, or a subacromial or acromioclavicular spur. Arthrography is normal during stages I (tendon inflammation) and II (fibrosis). The lack of objective findings often delays diagnosis until stage III (ischemic rotator cuff tear) is present. The purpose was to determine if MR imaging is useful in diagnosing this condition. T1-weighted surface coil scans were obtained on eight patients using a 0.3-T MR system. An axial scout allowed oblique alignment for imaging the osseous-soft tissue relationship and the supraspinatus tendon. MR is capable of displaying the specific pathologic anatomy of this disorder. Impinging spurs can be seen, and the adjacent tendon shows inferior displacement and abnormal signal intensity

What is the impingement-free range of motion of the asymptomatic hip in young adult males?

Science.gov (United States)

Larkin, Brian; van Holsbeeck, Marnix; Koueiter, Denise; Zaltz, Ira

2015-04-01

Femoroacetabular impingement is a recognized cause of chondrolabral injury. Although surgical treatment for impingement seeks to improve range of motion, there are very little normative data on dynamic impingement-free hip range of motion (ROM) in asymptomatic people. Hip ultrasound demonstrates labral anatomy and femoral morphology and, when used dynamically, can assist in measuring range of motion. The purposes of this study were (1) to measure impingement-free hip ROM until labral deflection is observed; and (2) to measure the maximum degree of sagittal plane hip flexion when further flexion is limited by structural femoroacetabular abutment. Forty asymptomatic adult male volunteers (80 hips) between the ages of 21 and 35 years underwent bilateral static and dynamic hip ultrasound examination. Femoral morphology was characterized and midsagittal flexion passive ROM was measured at two points: (1) at the initiation of labral deformation; and (2) at maximum flexion when the femur impinged on the acetabular rim. The mean age of the subjects was 28 ± 3 years and the mean body mass index was 25 ± 4 kg/m(2). Mean impingement-free hip passive flexion measured from full extension to initial labral deflection was 68° ± 17° (95% confidence interval [CI], 65-72). Mean maximum midsagittal passive flexion, measured at the time of bony impingement, was 96° ± 6° (95% CI, 95-98). Using dynamic ultrasound, we found that passive ROM in the asymptomatic hip was much less than the motion reported in previous studies. Measuring ROM using ultrasound is more accurate because it allows anatomic confirmation of terminal hip motion. Surgical procedures used to treat femoroacetabular impingement are designed to restore or increase hip ROM and their results should be evaluated in light of precise normative data. This study suggests that normal passive impingement-free femoroacetabular flexion in the young adult male is approximately 95°.

Experimental observations and modelling of thermal history within a steel plate during water jet impingement

International Nuclear Information System (INIS)

Liu, Z.D.; Fraser, D.; Samarasekera, I.V.; Lockhart, G.T.

2002-01-01

In order to investigate heat transfer of steel plates under a water jet impingement and to further simulate runout table operation in a hot strip mill, a full-scale pilot runout table facility was designed and constructed at the University of British Columbia (UBC). This paper describes the experimental details, data acquisition and data handling techniques for steel plates during water jet impingement by one circular water jet from an industrial header. Recorded visual observations at the impinging surface were obtained. The effects of cooling water temperature and impingement velocity on the heat transfer from a steel plate were studied. A two-dimensional finite element method-based transient inverse heat conduction model was developed. With the help of the model, heat fluxes and heat transfer coefficients along the impinging surface under various cooling conditions were calculated. The microstructural evolution of the steel plate was also investigated for the varying cooling conditions. Samples were obtained from each plate, polished, etched and then photographed. (author)

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 choice of inlet boundary conditions in numerical models, and it was found that it is necessary to model a jet tube length {{ L}{/}{ D}} > 0.5—where D is the inner diameter of the jet—in order to minimise modelling uncertainty.

Spray Formation of Herschel-Bulkley Fluids using Impinging Jets

Science.gov (United States)

Rodrigues, Neil; Gao, Jian; Chen, Jun; Sojka, Paul E.

2015-11-01

The impinging jet spray formation of two non-Newtonian, shear-thinning, Herschel-Bulkley fluids was investigated in this work. The water-based gelled solutions used were 1.0 wt.-% agar and 1.0 wt.-% kappa carrageenan. A rotational rheometer and a capillary viscometer were used to measure the strain-rate dependency of viscosity and the Herschel-Bulkley Extended (HBE) rheological model was used to characterize the shear-thinning behavior. A generalized HBE jet Reynolds number Rej , gen - HBE was used as the primary parameter to characterize the spray formation. A like-on-like impinging jet doublet was used to produce atomization. Shadowgraphs were captured in the plane of the sheet formed by the two jets using a CCD camera with an Nd:YAG laser beam providing the back-illumination. Typical behavior for impinging jet atomization using Newtonian liquids was not generally observed due to the non-Newtonian, viscous properties of the agar and kappa carrageenan gels. Instead various spray patterns were observed depending on Rej , gen - HBE. Spray characteristics of maximum instability wavelength and sheet breakup length were extracted from the shadowgraphs. Multi-University Research Initiative Grant Number W911NF-08-1-0171.

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.

Simulation of attenuation of thermal fluctuations near a plate impinged by jets

International Nuclear Information System (INIS)

Simoneau, J.P.

2001-01-01

In nuclear reactors, and especially in liquid sodium cooled ones, the combination of temperature differences inside cooling fluid, turbulent flows and high heat transfer coefficients is a potential source of the thermal striping process. Such a phenomenon has been studied for several years by using Large Eddy Simulation models. The present paper focuses on the attenuation of the thermal fluctuations in the boundary layer. The knowledge of this amplitude reduction is of prime importance for subsequent mechanical analyses. A Large Eddy Simulation model is implemented in the Star-cd code, including discretization of the viscous sublayer. The numerical simulation of two parallel jets impinging a flat plate in water is then performed and positively compared to corresponding experimental results. (author)

Hip kinematics and kinetics in persons with and without cam femoroacetabular impingement during a deep squat task.

Science.gov (United States)

Bagwell, Jennifer J; Snibbe, Jason; Gerhardt, Michael; Powers, Christopher M

2016-01-01

Previous studies have indicated that hip and pelvis kinematics may be altered during functional tasks in persons with femoroacetabular impingement. The purpose of this study was to compare hip and pelvis kinematics and kinetics during a deep squat task between persons with cam femoroacetabular impingement and pain-free controls. Fifteen persons with cam femoroacetabular impingement and 15 persons without cam femoroacetabular impingement performed a deep squat task. Peak hip flexion, abduction, and internal rotation, and mean hip extensor, adductor, and external rotator moments were quantified. Independent t-tests (αsquat descent compared to the control group, resulting in a more anteriorly tilted pelvis at the time peak hip flexion (12.5° (SD 17.1°) vs. 23.0° (SD 12.4°); P=0.024). The decreased hip internal rotation observed in persons with cam femoroacetabular impingement may be the result of bony impingement. Furthermore, the decrease in posterior pelvis tilt may contribute to impingement by further approximating the femoral head-neck junction with the acetabulum. Additionally, decreased hip extensor moments suggest that diminished hip extensor muscle activity may contribute to decreased posterior pelvis tilt. Copyright © 2015 Elsevier Ltd. All rights reserved.

Heat flux characteristics of spray wall impingement with ethanol, butanol, iso-octane, gasoline and E10 fuels

International Nuclear Information System (INIS)

Serras-Pereira, J.; Aleiferis, P.G.; Walmsley, H.L.; Davies, T.J.; Cracknell, R.F.

2013-01-01

. In addition, high-speed images of single droplets of fuel impinging onto the array of the heat flux sensor were acquired with simultaneous sampling of the heat flux signal in an attempt to provide further interpretation. The single droplet tests showed ability of the signals to quantify droplet mass impinged on the sensor. Analysis of the peak heat flux at static engine conditions quantified values of fuel temperature at impingement in agreement with the wet bulb temperatures predicted by the droplet evaporation model. Comparison of the static and motoring engine heat flux signals around the bore showed the effect of the intake flow on the spray’s pattern at impingement and demonstrated fuel presence on the liner that survived at exhaust valve open timing. The general behaviour was different for the alcohols to that of the hydrocarbons, with ethanol exhibiting the effect of its high latent heat on the signals and butanol exhibiting effects related to poor atomization and slow evaporation

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

Effectiveness of Kinesiotaping and Subacromial Corticosteroid Injection in Shoulder Impingement Syndrome.

Science.gov (United States)

Şahin Onat, Şule; Biçer, Seda; Şahin, Zehra; Küçükali Türkyilmaz, Ayşegül; Kara, Murat; Özbudak Demir, Sibel

2016-08-01

The aim of this study was to investigate whether kinesiotaping or subacromial corticosteroid injection provides additional benefit when used with nonsteroidal anti-inflammatory drugs (NSAIDs) in patients with shoulder impingement syndrome. Patients with shoulder impingement syndrome were divided into 3 groups as follows: NSAID group (n = 33), kinesiotaping group (kinesiotaping + NSAID) (n = 33), and injection group (subacromial corticosteroid injection + NSAID) (n = 33). Outcome measures including visual analog scale, shoulder ranges of motion, Shoulder Disability Questionnaire, and University of California-Los Angeles (UCLA) scale were evaluated before and after the treatment (fourth week). A total of 99 patients (21 male and 78 female patients) were enrolled in this study. Demographic and baseline clinical characteristics of the groups (except for body mass index and visual analog scale at night, both P = 0.05) were similar between the groups (all P > 0.05). Clinical parameters were found to have improved in the 3 groups (all P kinesiotaping and injection groups showed similar improvements (all P > 0.05), each group had better outcome than did the NSAID group as regards pain (activity visual analog scale), ranges of motion, and Shoulder Disability Questionnaire and UCLA scale scores (all P kinesiotaping or subacromial corticosteroid injection to NSAID treatment seems to have better/similar effectiveness in patients with shoulder impingement syndrome. Therefore, kinesiotaping might serve as an alternative treatment in case (injection of) corticosteroids are contraindicated. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES:: Upon completion of this article, the reader should be able to: (1) Delineate appropriate treatment options for shoulder impingement syndrome; (2) Identify treatment benefits of kinesiotaping and corticosteroid injections in shoulder impingement syndrome; and (3) Incorporate

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.

Numerical study of turbulent heat transfer from confined impinging jets using a pseudo-compressibility method

Energy Technology Data Exchange (ETDEWEB)

Rahman, M.; Rautaheimo, P.; Siikonen, T.

1997-12-31

A numerical investigation is carried out to predict the turbulent fluid flow and heat transfer characteristics of two-dimensional single and three impinging slot jets. Two low-Reynolds-number {kappa}-{epsilon} models, namely the classical model of Chien and the explicit algebraic stress model of Gatski and Speziale, are considered in the simulation. A cell-centered finite-volume scheme combined with an artificial compressibility approach is employed to solve the flow equations, using a diagonally dominant alternating direction implicit (DDADI) time integration method. A fully upwinded second order spatial differencing is adopted to approximate the convective terms. Roe`s damping term is used to calculate the flux on the cell face. A multigrid method is utilized for the acceleration of convergence. On average, the heat transfer coefficients predicted by both models show good agreement with the experimental results. (orig.) 17 refs.

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....

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

Quantitative and qualitative analyses of subacromial impingement by kinematic open MRI.

Science.gov (United States)

Tasaki, Atsushi; Nimura, Akimoto; Nozaki, Taiki; Yamakawa, Akira; Niitsu, Mamoru; Morita, Wataru; Hoshikawa, Yoshimitsu; Akita, Keiichi

2015-05-01

Quantitative and qualitative kinematic analyses of subacromial impingement by 1.2T open MRI were performed to determine the location of impingement and the involvement of the acromioclavicular joint. In 20 healthy shoulders, 10 sequential images in the scapular plane were taken in a 10-s pause at equal intervals from 30° to maximum abduction in neutral and internal rotation. The distances between the rotator cuff (RC) and the acromion and the acromioclavicular joint were measured. To comprehend the positional relationships, cadaveric specimens were also observed. Although asymptomatic, the RC came into contact with the acromion and the acromioclavicular joint in six and five cases, respectively. The superior RC acted as a depressor for the humeral head against the acromion as the shoulder elevated. The mean elevation angle and distance at the closest position between the RC and the acromion in neutral rotation were 93.5° and 1.6 mm, respectively, while those between the RC and the acromioclavicular joint were 86.7° and 2.0 mm. When comparing this distance and angle, there was no significant difference between the RC to the acromion and to the acromioclavicular joint. The minimum distance between the RC and the acromion was significantly shorter than that between the greater tuberosity and the acromion. The location of RC closest to the acromion and the acromioclavicular joint differed significantly. Although asymptomatic, contact was found between the RC and the acromion and the acromioclavicular joint. The important role of the RC to prevent impingement was observed, and hence, dysfunction of the RC could lead to impingement that could result in a RC lesion. The RC lesions may differ when they are caused by impingement from either the acromion or the acromioclavicular joint.

A review of recent developments on turbulent entrainment in stratified flows

International Nuclear Information System (INIS)

Cotel, Aline J

2010-01-01

Stratified interfaces are present in many geophysical flow situations, and transport across such an interface is an essential factor for correctly evaluating the physical processes taking place at many spatial and temporal scales in such flows. In order to accurately evaluate vertical and lateral transport occurring when a turbulent flow impinges on a stratified interface, the turbulent entrainment and vorticity generation mechanisms near the interface must be understood and quantified. Laboratory experiments were performed for three flow configurations: a vertical thermal, a sloping gravity current and a vertical turbulent jet with various tilt angles and precession speeds. All three flows impinged on an interface separating a two-layer stably stratified environment. The entrainment rate is quantified for each flow using laser-induced fluorescence and compared to predictions of Cotel and Breidenthal (1997 Appl. Sci. Res. 57 349-66). The possible applications of transport across stratified interfaces include the contribution of hydrothermal plumes to the global ocean energy budget, turbidity currents on the ocean floor, the design of lake de-stratification systems, modeling gas leaks from storage reservoirs, weather forecasting and global climate change.

A computational study of the impingement region of an unsteady subsonic jet

Science.gov (United States)

Jalamani, Zakaria A.; Nakamura, Shoichiro; Van Dalsem, William R.

1990-01-01

Vertical/Short Take-Off and Landing (V/STOL) aircraft may encounter operating difficulties while hovering near the ground. Lift loss, hot gas and debris ingestion, and landing surface damage are some of the potential problems which can result from the interaction of the propulsive jets with the airframe and ground. The purpose of the present work is to develop a detailed understanding of a flowfield, a jet exiting from a flat plate impacting a ground plane, that contains much of the essential physics of the complex flows encountered by V/STOL aircraft in hover. To achieve this, a high-resolution time-accurate numerical simulation of the impinging jet flow was performed. The numerical simulation is based on the solution of the laminar compressible Navier-Stokes equations using the Beam-Warming algorithm. Complex start-up and periodic jet and jet-induced vortex structures were captured, including the formation of primary and secondary jet-induced vortices and wall-jet separation. The formation and development of these phenomena are supported by experimental measurements and smoke visualization. Results are compared with appropriate experiments.

Current standard rules of combined anteversion prevent prosthetic impingement but ignore osseous contact in total hip arthroplasty.

Science.gov (United States)

Weber, Markus; Woerner, Michael; Craiovan, Benjamin; Voellner, Florian; Worlicek, Michael; Springorum, Hans-Robert; Grifka, Joachim; Renkawitz, Tobias

2016-12-01

In this prospective study of 135 patients undergoing cementless total hip arthroplasty (THA) we asked whether six current definitions of combined anteversion prevent impingement and increase postoperative patient individual impingement-free range-of-motion (ROM). Implant position was measured by an independent, external institute on 3D-CT performed six weeks post-operatively. Post-operative ROM was calculated using a CT-based algorithm detecting osseous and/or prosthetic impingement by virtual hip movement. Additionally, clinical ROM was evaluated pre-operatively and one-year post-operatively by a blinded observer. Combined component position of cup and stem according to the definitions of Ranawat, Widmer, Dorr, Hisatome and Yoshimine inhibited prosthetic impingement in over 90 %, while combined osseous and prosthetic impingement still occurred in over 40 % of the cases. The recommendations by Jolles, Widmer, Dorr, Yoshimine and Hisatome enabled higher flexion (p ≤ 0.001) and internal rotation (p ≤ 0.006). Clinically, anteversion rules of Widmer and Yoshimine provided one-year post-operatively statistically but not clinically relevant higher internal rotation (p ≤0.034). Standard rules of combined anteversion detect prosthetic but fail to prevent combined osseous and prosthetic impingement in THA. Future models will have to account for the patient-individual anatomic situation to ensure impingement-free ROM.

Impingement and entrainment of fishes at the Savannah River Plant: an NPDES 316b demonstration

International Nuclear Information System (INIS)

McFarlane, R.W.; Frietsche, R.F.; Miracle, R.D.

1978-02-01

Environmental impacts of the Savannah River Plant's withdrawal of Savannah River water include impingement of juvenile and adult fish on trash removal screens, and entrainment of planktonic fish eggs and larval fish into the pumping system. The Savannah River Plant (SRP) has the capacity to pump 3.6 million cubic meters of water per day--25% of the minimal river discharge--for cooling and other purposes. Present removal is 7% of the actual river discharge. In the river and intake canals reside sixty-nine species of fishes. The species composition of the resident fish community of the intake canals is similar to the species composition in the river, but different in relative species abundance. The dominant sunfishes tend to reside in the canals for long periods and seldom go from canal to canal. The fish impingement rate at the plant ranks very low in comparison with electric power plants on inland waters. Thirty-five species of fishes were impinged during 1977. The average impingement rate of 7.3 fish per day extrapolates to 2,680 fish per year. No single species comprised more than 10% of the sample. The most commonly impinged species were bluespotted sunfish, warmouth, channel catfish, and yellow perch. The relative abundance of those species impinged deviates from their relative abundance in the canal fish population

Cryogenic Impinging Jets Subjected to High Frequency Transverse Acoustic Forcing in a High Pressure Environment

Science.gov (United States)

2016-07-27

impingement sheet – Probably due to a impingement point physically moving Distribution A: Approved for Public Release; Distribution Unlimited. PA# 16333 22...AIAA-92- 0458 30th ASM 7. N. Bremond and E. Villermaux, “Atomization by jet impact”, J. Fluid Mech 2006, vol.549, 273-306 8. W.E. Anderson, H. M. Ryan...Sheets formed by Impinging Jets in High Pressure Environments,” AIAA-2004-3526 40th ASM 11. X. Chen, D. Ma, and V. Yang, “Mechanism Study of Impact Wave

[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.

Impingement syndrome and rotator cuff tears: US findings in 140 patients

International Nuclear Information System (INIS)

Malvestiti, Oreste; Scorsolini, Alessandro; Ratti, Francesco; Ferraris, Giuseppe; Columbaro, Guido; Mariani, Claudio

1997-01-01

The authors investigated the role of rotator cuff impingement in causing tears of supraspinatus and biceps tendons and the comparative reliability of plain radiography and sonography (US). One hundred forty patients with symtoms referrable to the rotator cuff were examined with plain radiography and US of the shoulder. The differential diagnosis must distinguish all these common causes of shoulder dysfunction and cuff problems from other conditions. The authors conclude that US and plain radiography are accurate routine tests of rotator cuff integrity and rotator cuff impingement

Anterolateral ankle impingement in adolescents: outcomes of nonoperative and operative treatment.

Science.gov (United States)

Edmonds, Eric W; Chambers, Reid; Kaufman, Elizabeth; Chambers, Henry G

2010-03-01

Ankle sprains in adolescents usually resolve with conservative management but a few patients may develop ankle impingement syndrome. There have been adult studies addressing surgical treatment of this pathology, but our study evaluated the surgical management of anterolateral ankle impingement in adolescents by comparing their outcomes after nonoperative treatment and subsequent surgical intervention. Thirteen patients (children and adolescents) diagnosed with ankle impingement by history, physical examination, and magnetic resonance imaging during a 9-year period at our institution underwent eventual arthroscopic debridement. A retrospective chart review of these patients was performed and they were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) functional rating scale on 3 separate occasions: (1) initial presentation, (2) termination of nonoperative management, and (3) final postoperative follow-up visit. Thirteen adolescents (11 girls and 2 boys; 14 ankles) with a mean age of 15.6 (11.9-18.3) years met the inclusion criteria; of these, all had arthroscopic surgery. Mean duration of reported symptoms was 9.6 (4-15) months and mean duration of nonoperative management (physical therapy, activity modifications) was 6.9 (2-12) months. The mean AOFAS rating (out of 100 total) at initial presentation was 68.4 (40-84) and after nonoperative management was no better with a mean of 68.2 (63-76). The mean AOFAS rating at final follow-up was 90.6 (52-100), which was statistically significant (Pankle impingement in the adolescent population.

The influence of material hardness on liquid droplet impingement erosion

International Nuclear Information System (INIS)

Fujisawa, Nobuyuki; Yamagata, Takayuki; Takano, Shotaro; Saito, Kengo; Morita, Ryo; Fujiwara, Kazutoshi; Inada, Fumio

2015-01-01

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

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.

Gastric Adenomyoma: The Unexpected Mimicker

Directory of Open Access Journals (Sweden)

Marcela Adriana Duran Álvarez

2017-01-01

Full Text Available Gastric adenomyoma is a rare benign tumor composed of epithelial structures and smooth muscle stroma. Here, we report an unusual case of gastric adenomyoma mostly composed of smooth muscle that was incidentally found during a laparoscopic intervention. On radiology, it mimicked an acquired hypertrophic pyloric stenosis in an adult patient, and pathologically it resembled a pure smooth muscle hamartoma. Complete submission of the lesion for histology was necessary to find the epithelial component and make the right diagnosis. As a mimicker of benign and malignant entities, gastric adenomyoma is usually an unexpected finding after surgery. The aim of this report is to analyze this adenomyoma variant in the setting of an unexplained thickening of the gastric wall, with explanations concerning histogenesis and biological potential.

Imaging evaluation of the hip after arthroscopic surgery for femoroacetabular impingement

Energy Technology Data Exchange (ETDEWEB)

Crim, Julia [University of Missouri at Columbia, Columbia, MO (United States)

2017-10-15

Arthroscopic surgery for femoroacetabular impingement (FAI) is increasingly frequently performed. Initial reports were that complications were very low, but as experience has increased, a number of long-term complications, in addition to factors related to poor clinical outcomes, have been identified. This review describes the normal and abnormal postoperative imaging appearance of the hip after arthroscopy for FAI. Abnormalities discussed include incomplete resection or over-resection of the impingement lesion, heterotopic ossification, cartilage damage, chondrolysis, instability and dislocation, recurrent labral tear, adhesions, psoas atrophy, infection, and avascular necrosis. (orig.)

Imaging evaluation of the hip after arthroscopic surgery for femoroacetabular impingement

International Nuclear Information System (INIS)

Crim, Julia

2017-01-01

Arthroscopic surgery for femoroacetabular impingement (FAI) is increasingly frequently performed. Initial reports were that complications were very low, but as experience has increased, a number of long-term complications, in addition to factors related to poor clinical outcomes, have been identified. This review describes the normal and abnormal postoperative imaging appearance of the hip after arthroscopy for FAI. Abnormalities discussed include incomplete resection or over-resection of the impingement lesion, heterotopic ossification, cartilage damage, chondrolysis, instability and dislocation, recurrent labral tear, adhesions, psoas atrophy, infection, and avascular necrosis. (orig.)

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.

[Primary central nervous system lymphoma mimicking ventriculitis].

Science.gov (United States)

Yamamoto, Shiro; Nagano, Seiji; Shibata, Sumiya; Kunieda, Takeharu; Imai, Yukihiro; Kohara, Nobuo

2013-01-01

A 66-year-old man presented with deteriorated bradykinesia, gait disturbance, disorientation, and urinary incontinence for three weeks. Magnetic resonance imaging (MRI) showed dilatation of the ventricles. Cerebrospinal fluid (CSF) examination demonstrated lymphocytic pleocytosis, elevation of protein levels, and decreased of glucose levels. A gadolinium-enhanced MRI revealed lesions in the ventricular wall and choroid plexus, mimicking ventriculitis. No evidence of bacterial, fungal, mycobacterial, or viral infections were observed in the CSF. Flow cytometry of CSF showed predominance of CD20+, λ+ cells. PCR examination of CSF revealed positive IgH gene rearrangement, suggesting B cell lymphoma. Endoscopic brain biopsy showed diffuse large B cell lymphoma. As the patient had no evidence of lymphoma in the other organs, we made a diagnosed of primary central nervous system lymphoma (PCNSL). A limited intraventricular spread of PCNSL is rare but important as one of differential diagnosis of ventriculitis.

Impingement wastage experiments with 9Cr 1Mo steel

Energy Technology Data Exchange (ETDEWEB)

Kishore, S., E-mail: skishore@igcar.gov.in [IGCAR (India); Beauchamp, François; Allou, Alexandre [CEA (France); Kumar, A. Ashok; Chandramouli, S.; Rajan, K.K. [IGCAR (India)

2016-02-15

Highlights: • Sodium heated steam generators are crucial components of fast breeder reactors. • A leak in steam generator tube will cause sodium water reaction that damages the tubes. • A collaborative study by CEA and IGCAR was conducted to quantify the extent of damage on 9Cr 1Mo tube due to a steam/water leak. • It was compared against the predictions of PROPANA code. - Abstract: Steam Generator (SG) is one of the vital components of sodium cooled fast reactor (SFR). The main safety concern with SG is a probable sodium–water reaction. In case, one of its water/steam carrying tubes leaks, water/steam gets into contact with sodium causing sodium-water reaction, which is highly exothermic and producing corrosive NaOH and hydrogen. The ejecting reaction products at high temperature, impinges upon adjacent tubes by a process called impingement wastage. It could damage one of the neighboring tubes in a short time, if the detection and protection systems are failing. IGCAR and CEA carried out a collaborative study on impingement wastage of 9Cr 1Mo steel, which is one of the candidate materials for SFR SG tubes. The studies comprise of experimental works at IGCAR and simulation works with PROPANA code at CEA. This paper brings out the data and experience gained through this cooperative work.

Rapid preparation of high electrochemical performance LiFePO4/C composite cathode material with an ultrasonic-intensified micro-impinging jetting reactor.

Science.gov (United States)

Dong, Bin; Huang, Xiani; Yang, Xiaogang; Li, Guang; Xia, Lan; Chen, George

2017-11-01

A joint chemical reactor system referred to as an ultrasonic-intensified micro-impinging jetting reactor (UIJR), which possesses the feature of fast micro-mixing, was proposed and has been employed for rapid preparation of FePO 4 particles that are amalgamated by nanoscale primary crystals. As one of the important precursors for the fabrication of lithium iron phosphate cathode, the properties of FePO 4 nano particles significantly affect the performance of the lithium iron phosphate cathode. Thus, the effects of joint use of impinging stream and ultrasonic irradiation on the formation of mesoporous structure of FePO 4 nano precursor particles and the electrochemical properties of amalgamated LiFePO 4 /C have been investigated. Additionally, the effects of the reactant concentration (C=0.5, 1.0 and 1.5molL -1 ), and volumetric flow rate (V=17.15, 51.44, and 85.74mLmin -1 ) on synthesis of FePO 4 ·2H 2 O nucleus have been studied when the impinging jetting reactor (IJR) and UIJR are to operate in nonsubmerged mode. It was affirmed from the experiments that the FePO 4 nano precursor particles prepared using UIJR have well-formed mesoporous structures with the primary crystal size of 44.6nm, an average pore size of 15.2nm, and a specific surface area of 134.54m 2 g -1 when the reactant concentration and volumetric flow rate are 1.0molL -1 and 85.74mLmin -1 respectively. The amalgamated LiFePO 4 /C composites can deliver good electrochemical performance with discharge capacities of 156.7mAhg -1 at 0.1C, and exhibit 138.0mAhg -1 after 100 cycles at 0.5C, which is 95.3% of the initial discharge capacity. Copyright © 2017. Published by Elsevier B.V.

Polymerization of a divalent/tetravalent metal-storing atom-mimicking dendrimer

OpenAIRE

Albrecht, Ken; Hirabayashi, Yuki; Otake, Masaya; Mendori, Shin; Tobari, Yuta; Azuma, Yasuo; Majima, Yutaka; Yamamoto, Kimihisa

2016-01-01

The phenylazomethine dendrimer (DPA) has a layer-by-layer electron density gradient that is an analog of the Bohr atom (atom mimicry). In combination with electron pair mimicry, the polymerization of this atom-mimicking dendrimer was achieved. The valency of the mimicked atom was controlled by changing the chemical structure of the dendrimer. By mimicking a divalent atom, a one-dimensional (1D) polymer was obtained, and by using a planar tetravalent atom mimic, a 2D polymer was obtained. Thes...

Impinging jets controlled by fluidic input signal

Czech Academy of Sciences Publication Activity Database

Tesař, Václav; Trávníček, Zdeněk; Peszyński, K.

2016-01-01

Roč. 249, October (2016), s. 85-92 ISSN 0924-4247 R&D Projects: GA ČR GA13-23046S; GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : fluidics * jets * impinging jets * coanda effect Subject RIV: BK - Fluid Dynamics Impact factor: 2.499, year: 2016 http://www.sciencedirect.com/science/article/pii/S0924424716303880

Assessment of congruence and impingement of the hip joint in professional ballet dancers: a motion capture study.

Science.gov (United States)

Charbonnier, Caecilia; Kolo, Frank C; Duthon, Victoria B; Magnenat-Thalmann, Nadia; Becker, Christoph D; Hoffmeyer, Pierre; Menetrey, Jacques

2011-03-01

Early hip osteoarthritis in dancers could be explained by femoroacetabular impingements. However, there is a lack of validated noninvasive methods and dynamic studies to ascertain impingement during motion. Moreover, it is unknown whether the femoral head and acetabulum are congruent in typical dancing positions. The practice of some dancing movements could cause a loss of hip joint congruence and recurrent impingements, which could lead to early osteoarthritis. Descriptive laboratory study. Eleven pairs of female dancer's hips were motion captured with an optical tracking system while performing 6 different dancing movements. The resulting computed motions were applied to patient-specific hip joint 3-dimensional models based on magnetic resonance images. While visualizing the dancer's hip in motion, the authors detected impingements using computer-assisted techniques. The range of motion and congruence of the hip joint were also quantified in those 6 recorded dancing movements. The frequency of impingement and subluxation varied with the type of movement. Four dancing movements (développé à la seconde, grand écart facial, grand écart latéral, and grand plié) seem to induce significant stress in the hip joint, according to the observed high frequency of impingement and amount of subluxation. The femoroacetabular translations were high (range, 0.93 to 6.35 mm). For almost all movements, the computed zones of impingement were mainly located in the superior or posterosuperior quadrant of the acetabulum, which was relevant with respect to radiologically diagnosed damaged zones in the labrum. All dancers' hips were morphologically normal. Impingements and subluxations are frequently observed in typical ballet movements, causing cartilage hypercompression. These movements should be limited in frequency. The present study indicates that some dancing movements could damage the hip joint, which could lead to early osteoarthritis.

Cavitation phenomena in mechanical heart valves: studied by using a physical impinging rod system.

Science.gov (United States)

Lo, Chi-Wen; Chen, Sheng-Fu; Li, Chi-Pei; Lu, Po-Chien

2010-10-01

When studying mechanical heart valve cavitation, a physical model allows direct flow field and pressure measurements that are difficult to perform with actual valves, as well as separate testing of water hammer and squeeze flow effects. Movable rods of 5 and 10 mm diameter impinged same-sized stationary rods to simulate squeeze flow. A 24 mm piston within a tube simulated water hammer. Adding a 5 mm stationary rod within the tube generated both effects simultaneously. Charged-coupled device (CCD) laser displacement sensors, strobe lighting technique, laser Doppler velocimetry (LDV), particle image velocimetry (PIV) and high fidelity piezoelectric pressure transducers measured impact velocities, cavitation images, squeeze flow velocities, vortices, and pressure changes at impact, respectively. The movable rods created cavitation at critical impact velocities of 1.6 and 1.2 m/s; squeeze flow velocities were 2.8 and 4.64 m/s. The isolated water hammer created cavitation at 1.3 m/s piston speed. The combined piston and stationary rod created cavitation at an impact speed of 0.9 m/s and squeeze flow of 3.2 m/s. These results show squeeze flow alone caused cavitation, notably at lower impact velocity as contact area increased. Water hammer alone also caused cavitation with faster displacement. Both effects together were additive. The pressure change at the vortex center was only 150 mmHg, which cannot generate the magnitude of pressure drop required for cavitation bubble formation. Cavitation occurred at 3-5 m/s squeeze flow, significantly different from the 14 m/s derived by Bernoulli's equation; the temporal acceleration of unsteady flow requires further study.

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.

Mimicking anti-correlations with classical interference

International Nuclear Information System (INIS)

Godoy, S; Seifert, B; Wallentowitz, S

2013-01-01

It is shown how classical laser light impinging on a beam splitter with internal reflections may mimic anti-correlations of the detected outputs, similar to those observed for anti-bunched light. The experimentally observed anti-correlation may be interpreted as a classical Hong–Ou–Mandel dip. (paper)

Numerical analysis of droplet impingement using the moving particle semi-implicit method

International Nuclear Information System (INIS)

Xiong, Jinbiao; Koshizuka, Seiichi; Sakai, Mikio

2010-01-01

Droplet impingement onto a rigid wall is simulated in two and three dimensions using the moving particle semi-implicit method. In two-dimensional calculations, the convergence is achieved and the propagation of a shockwave in a droplet is captured. The average pressure on the contact area decreases gradually after the maximum value. The numerically obtained maximum average impact pressure agrees with the Heymann correlation. A large shear stress appears at the contact edge due to jetting. A parametric study shows that the droplet diameter has only a minor effect on the pressure load due to droplet impingement. When the impingement takes place from an impact angle of π/4 rad, the pressure load and shear stress show a dependence only on the normal velocity to the wall. A comparison between the three-dimensional and two-dimensional results shows that consideration of the three-dimensional effect can decrease the average impact pressure by about 12%. (author)

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.

Mapping of local argon impingement on a virtual surface: an insight for gas injection during FEBID

Energy Technology Data Exchange (ETDEWEB)

Wanzenboeck, H.D.; Hochleitner, G.; Mika, J.; Shawrav, M.M.; Gavagnin, M.; Bertagnolli, E. [Vienna University of Technology, Institute for Solid State Electronics, Vienna (Austria)

2014-12-15

During the last decades, focused electron beam induced deposition (FEBID) has become a successful approach for direct-write fabrication of nanodevices. Such a deposition technique relies on the precursor supply to the sample surface which is typically accomplished by a gas injection system using a tube-shaped injector nozzle. This precursor injection strategy implies a position-dependent concentration gradient on the surface, which affects the geometry and chemistry of the final nanodeposit. Although simulations already proposed the local distribution of nozzle-borne gas molecules impinging on the surface, this isolated step in the FEBID process has never been experimentally measured yet. This work experimentally investigates the local distribution of impinging gas molecules on the sample plane, isolating the direct impingement component from surface diffusion or precursor depletion by deposition. The experimental setup used in this work maps and quantifies the local impinging rate of argon gas over the sample plane. This setup simulates the identical conditions for a precursor molecule during FEBID. Argon gas was locally collected with a sniffer tube, which is directly connected to a residual gas analyzer for quantification. The measured distribution of impinging gas molecules showed a strong position dependence. Indeed, a 300-μm shift of the deposition area to a position further away from the impingement center spot resulted in a 50 % decrease in the precursor impinging rate on the surface area. With the same parameters, the precursor distribution was also simulated by a Monte Carlo software by Friedli and Utke and showed a good correlation between the empirical and the simulated precursor distribution. The results hereby presented underline the importance of controlling the local precursor flux conditions in order to obtain reproducible and comparable deposition results in FEBID. (orig.)

Mapping of local argon impingement on a virtual surface: an insight for gas injection during FEBID

International Nuclear Information System (INIS)

Wanzenboeck, H.D.; Hochleitner, G.; Mika, J.; Shawrav, M.M.; Gavagnin, M.; Bertagnolli, E.

2014-01-01

During the last decades, focused electron beam induced deposition (FEBID) has become a successful approach for direct-write fabrication of nanodevices. Such a deposition technique relies on the precursor supply to the sample surface which is typically accomplished by a gas injection system using a tube-shaped injector nozzle. This precursor injection strategy implies a position-dependent concentration gradient on the surface, which affects the geometry and chemistry of the final nanodeposit. Although simulations already proposed the local distribution of nozzle-borne gas molecules impinging on the surface, this isolated step in the FEBID process has never been experimentally measured yet. This work experimentally investigates the local distribution of impinging gas molecules on the sample plane, isolating the direct impingement component from surface diffusion or precursor depletion by deposition. The experimental setup used in this work maps and quantifies the local impinging rate of argon gas over the sample plane. This setup simulates the identical conditions for a precursor molecule during FEBID. Argon gas was locally collected with a sniffer tube, which is directly connected to a residual gas analyzer for quantification. The measured distribution of impinging gas molecules showed a strong position dependence. Indeed, a 300-μm shift of the deposition area to a position further away from the impingement center spot resulted in a 50 % decrease in the precursor impinging rate on the surface area. With the same parameters, the precursor distribution was also simulated by a Monte Carlo software by Friedli and Utke and showed a good correlation between the empirical and the simulated precursor distribution. The results hereby presented underline the importance of controlling the local precursor flux conditions in order to obtain reproducible and comparable deposition results in FEBID. (orig.)

Mapping of local argon impingement on a virtual surface: an insight for gas injection during FEBID

Science.gov (United States)

Wanzenboeck, H. D.; Hochleitner, G.; Mika, J.; Shawrav, M. M.; Gavagnin, M.; Bertagnolli, E.

2014-12-01

During the last decades, focused electron beam induced deposition (FEBID) has become a successful approach for direct-write fabrication of nanodevices. Such a deposition technique relies on the precursor supply to the sample surface which is typically accomplished by a gas injection system using a tube-shaped injector nozzle. This precursor injection strategy implies a position-dependent concentration gradient on the surface, which affects the geometry and chemistry of the final nanodeposit. Although simulations already proposed the local distribution of nozzle-borne gas molecules impinging on the surface, this isolated step in the FEBID process has never been experimentally measured yet. This work experimentally investigates the local distribution of impinging gas molecules on the sample plane, isolating the direct impingement component from surface diffusion or precursor depletion by deposition. The experimental setup used in this work maps and quantifies the local impinging rate of argon gas over the sample plane. This setup simulates the identical conditions for a precursor molecule during FEBID. Argon gas was locally collected with a sniffer tube, which is directly connected to a residual gas analyzer for quantification. The measured distribution of impinging gas molecules showed a strong position dependence. Indeed, a 300-µm shift of the deposition area to a position further away from the impingement center spot resulted in a 50 % decrease in the precursor impinging rate on the surface area. With the same parameters, the precursor distribution was also simulated by a Monte Carlo software by Friedli and Utke and showed a good correlation between the empirical and the simulated precursor distribution. The results hereby presented underline the importance of controlling the local precursor flux conditions in order to obtain reproducible and comparable deposition results in FEBID.

Improvement of a wall thinning rate model for liquid droplet impingement erosion. Implementation of liquid film thickness model with consideration of film behavior

International Nuclear Information System (INIS)

Morita, Ryo

2014-01-01

Liquid droplet impingement erosion (LDI) is defined as an erosion phenomenon caused by high-speed droplet attack in a steam flow. Pipe wall thinning by LDI is sometimes observed in a steam piping system of a power plant. As LDI usually occurs very locally and is difficult to detect, predicting LDI location is required for safe operation of power plant systems. Therefore, we have involved in the research program to develop prediction tools that will be used easily in actual power plants. Our previous researches developed a thinning rate evaluation model due to LDI (LDI model) and the evaluation system of the thinning rate and the thinning shape within a practically acceptable time (LDI evaluation system). Though the LDI model can include a cushioning effect of liquid film which is generated on the material surface by droplet impingement as an empirical equation with fluid parameter, the liquid film thickness is not clarified due to complex flow condition. In this study, to improve the LDI model and the LDI evaluation system, an analytical model of the liquid film thickness was proposed with consideration of the liquid film flow behavior on the material surface. The mass balance of the liquid film was considered, and the results of CFD calculations and existing researches were applied to obtain the liquid film thickness in this model. As a result of the LDI evaluation of the new LDI model with liquid film model, improvement of the LDI model was achieved. (author)

Hair flow sensors: from bio-inspiration to bio-mimicking—a review

International Nuclear Information System (INIS)

Tao, Junliang; Yu, Xiong

2012-01-01

A great many living beings, such as aquatics and arthropods, are equipped with highly sensitive flow sensors to help them survive in challenging environments. These sensors are excellent sources of inspiration for developing application-driven artificial flow sensors with high sensitivity and performance. This paper reviews the bio-inspirations on flow sensing in nature and the bio-mimicking efforts to emulate such sensing mechanisms in recent years. The natural flow sensing systems in aquatics and arthropods are reviewed to highlight inspirations at multiple levels such as morphology, sensing mechanism and information processing. Biomimetic hair flow sensors based on different sensing mechanisms and fabrication technologies are also reviewed to capture the recent accomplishments and to point out areas where further progress is necessary. Biomimetic flow sensors are still in their early stages. Further efforts are required to unveil the sensing mechanisms in the natural biological systems and to achieve multi-level bio-mimicking of the natural system to develop their artificial counterparts. (topical review)

Cam Femoroacetabular Impingement as a Possible Explanation of Recalcitrant Anterior Knee Pain

OpenAIRE

Sanchis-Alfonso, Vicente; Tey, Marc; Monllau, Joan Carles

2016-01-01

We present a case of a patient with chronic anterior knee pain (AKP) recalcitrant to conservative treatment who returned to our office for severe hip pain secondary to Cam femoroacetabular impingement (Cam FAI) at 10 months after the onset of knee pain. This case highlights the fact that the main problem is not in the patella but in the hip in some patients with AKP. We hypothesize that there is an external femoral rotation in order to avoid the impingement and therefore the hip pain in patie...

A denuder-impinger system with in situ derivatization followed by gas chromatography-mass spectrometry for the determination of gaseous iodine-containing halogen species.

Science.gov (United States)

Huang, Ru-Jin; Hoffmann, Thorsten

2008-11-14

Reactive iodine species have been suggested to play an important role in the atmosphere (e.g. tropospheric ozone depletion, coastal new particle formation). However, there still exist major uncertainties about their atmospheric chemistry, mostly due to the lack of analytical approaches for the accurate speciation of certain key compounds. In this study, 1,3,5-trimethoxybenzene (1,3,5-TMB)-coated denuder proved to be suitable for the differentiation between gaseous interhalogens (iodine monochloride (ICl), iodine monobromide (IBr)) and molecular iodine (I2) based on a selective collection/derivatization method. The results of the denuder sampling were compared with the results of impinger sampling in water, methanol and carbon tetrachloride solutions of 1,3,5-TMB. ICl and IBr are converted into 1-iodo-2,4,6-trimethoxybenzene (1-iodo-2,4,6-TMB) and 1-bromo-2,4,6-trimethoxybenzene (1-bromo-2,4,6-TMB), respectively, in the denuder systems. The respective collection efficiency is 99.2% for ICl and 92.6% for IBr, at 500mLmin(-1) gas flow rate. The collection efficiency for I2 is lower than 1% in the same denuder system, but significantly increases to about 90% in the aqueous 1,3,5-TMB loaded impinger. The denuder-impinger coupled system was then used to differentiate and to collect the ICl, IBr and I2 gas mixtures, followed by gas chromatography-ion trap mass spectrometry (GC-MS) determination. The precision of the method is in general better than 9.1%. The parameters affecting denuder operation including sampling flow rate, sampling duration, and relative humidity have been evaluated. The presented method provides an attractive protocol for iodine species analysis for atmospheric chemistry research.

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

OpenAIRE

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

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 ce...

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.

Shoulder impingement syndrome : evaluation of the causes with MRI

International Nuclear Information System (INIS)

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; Choi, Yun Sun

1999-01-01

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

Clinical application of arthroscopy in the diagnosis and treatment of anterior impingement syndrome of the ankle joint in physical workers.

Science.gov (United States)

Wu, Wen-Te; Chen, Zhi-Wei; Zhou, Yu-Cheng

2012-10-01

To evaluate the clinical application of arthroscopy in the diagnosis and treatment of anterior impingement syndrome of the ankle joint in physical workers. A retrospective study was carried out at the Department of Orthopedics, the First Hospital affiliated to Nanhua University, Hengyang, China from March 2005 to December 2011. Seventeen cases of anterior impingement syndrome of the ankle joint were confirmed, and treated through arthroscopy. All these patients conformed to regular follow-up postoperatively, and clinical details, as well as postoperative prognosis were retrieved and analyzed retrospectively. The efficacy was evaluated by the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot-ankle scoring system, and pain relief was assessed by visual analogue scoring (VAS). Anterolateral impingement syndrome was found in 11 patients, anteromedial impingement syndrome in 4, while anterior impingement syndrome in 2 via arthroscopic examination. The VAS was reduced from 5.2-1.1, and the AOFAS score was elevated from 76.4-95.8 postoperatively; both of which demonstrated statistical differences when compared to preoperative scores. It was also found that concomitant cartilage damage was an indicator of poor prognosis in arthroscopic treatment of impingement syndrome of the ankle joint. Satisfactory results could be achieved for physical workers with anterior impingement syndrome treated by arthroscopy. As the cartilage damage is an indicator of poor prognosis, an early operation is advocated when the prognosis of anterior impingement syndrome is confirmed.

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.

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.

Low-Gravity Mimicking Simulants and Evaluation of Simulant Flow, Phase I

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...

The Effect of Impingement Velocity and Angle Variation on the Erosion Corrosion Performance of API 5L-X65 Carbon Steel in a Flow Loop

Directory of Open Access Journals (Sweden)

Ihsan UlHaq Toor

2018-05-01

Full Text Available Erosion corrosion performance of API 5L-X65 carbon steel was investigated at three different impingement velocities (3, 6 & 12 m/s, five different angles (15, 30, 45, 60, & 90°, and with/without solid particles (average particle size of 314 µm. The experiments were conducted in 0.2 M NaCl solution at room temperature for a duration of 24 h and the results showed that the maximum erosion corrosion rate was observed at 45° irrespective of the velocity. The highest erosion corrosion rate at 45° was due to the balance between the shear and normal impact stress at this angle. Ploughing, deep craters, and micro-forging/plastic deformation were found to be the main erosion corrosion mechanisms. The maximum wear scar depth measured using optical profilometery was found to be 51 µm (average at an impingement angle of 45°.

Investigation on flow oscillation modes and aero-acoustics generation mechanism in cavity

Science.gov (United States)

Yang, Dang-Guo; Lu, Bo; Cai, Jin-Sheng; Wu, Jun-Qiang; Qu, Kun; Liu, Jun

2018-05-01

Unsteady flow and multi-scale vortex transformation inside a cavity of L/D = 6 (ratio of length to depth) at Ma = 0.9 and 1.5 were studied using the numerical simulation method of modified delayed detached eddy simulation (DDES) in this paper. Aero-acoustic characteristics for the cavity at same flow conditions were obtained by the numerical method and 0.6 m by 0.6 m transonic and supersonic wind-tunnel experiments. The analysis on the computational and experimental results indicates that some vortex generates from flow separation in shear-layer over the cavity, and the vortex moves from forward to downward of the cavity at some velocity, and impingement of the vortex and the rear-wall of the cavity occurs. Some sound waves spread abroad to the cavity fore-wall, which induces some new vortex generation, and the vortex sheds, moves and impinges on the cavity rear-wall. New sound waves occur. The research results indicate that sound wave feedback created by the impingement of the shedding-vortices and rear cavity face leads to flow oscillations and noise generation inside the cavity. Analysis on aero-acoustic characteristics inside the cavity is feasible. The simulated self-sustained flow-oscillation modes and peak sound pressure on typical frequencies inside the cavity agree well with Rossiter’s and Heller’s predicated results. Moreover, the peak sound pressure occurs in the first and second flow-oscillation modes and most of sound energy focuses on the low-frequency region. Compared with subsonic speed (Ma = 0.9), aerodynamic noise is more intense at Ma = 1.5, which is induced by compression wave or shock wave in near region of fore and rear cavity face.

Quantifying cell adhesion through impingement of a controlled microjet

NARCIS (Netherlands)

Visser, C.W.; Gielen, Marise V.; Gielen, Marise Vera; Hao, Zhenxia; le Gac, 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

Clear cell carcinoma of the ovary mimicking struma ovarii and carcinoid tumor.

Science.gov (United States)

Alduaij, Ahmad; Quddus, M Ruhul

2011-04-01

Clear cell carcinomas are considered as high-grade tumor often with poor prognosis. We describe 2 cases of clear cell carcinomas of the ovary mimicking benign or less aggressive tumors encountered in the female genital track. The first case is mimicking a benign monodermal teratoma, the so-called struma ovarii, and the second mimicking a carcinoid tumor. Copyright © 2011 Elsevier Inc. All rights reserved.

Comparison of methods for detection and enumeration of airborne microorganisms collected by liquid impingement.

OpenAIRE

Terzieva, S; Donnelly, J; Ulevicius, V; Grinshpun, S A; Willeke, K; Stelma, G N; Brenner, K P

1996-01-01

Bacterial agents and cell components can be spread as bioaerosols, producing infections and asthmatic problems. This study compares four methods for the detection and enumeration of aerosolized bacteria collected in an AGI-30 impinger. Changes in the total and viable concentrations of Pseudomonas fluorescens in the collection fluid with respect to time of impingement were determined. Two direct microscopic methods (acridine orange and BacLight) and aerodynamic aerosol-size spectrometry (Aeros...

Preliminary study of image findings of femoroacetabular impingement

International Nuclear Information System (INIS)

Guo Zhe; Zhang Jing; Hong Nan; Cheng Xiaoguang

2010-01-01

Objective: To assess the image findings of femoroacetabular impingement (FAI). Methods: Image findings of 9 patients with surgically proved femoroacetabular impingement were retrospectively reviewed for characteristic image findings of FAI. All 9 patients underwent X-ray examinations and MRI of affected hip, and 1 patient underwent MR arthrography (MRA) additionally. Results: X-ray examinations of all 9 patients showed bump at femoral head-neck junction or overcoverage of the acetabular. MRI showed various degrees of injury of anterosuperior labrum in all 9 patients. The injuries were stage Ⅰ A in 2 cases, stage Ⅰ B in 3, stage Ⅱ A in 2, and stage Ⅱ B in 2. MRA of the case showed tears of anterosuperior labrum, with contrast media entering into the teared labrum. There were sclerosis and cystic degeneration of subchondral bone of femoral head in 2 cases, and these findings were confirmed as cartilage delamination by surgery. Conclusions: MRI can display the injures of labrum and articular cartilage, which is helpful to the early diagnosis of' FAI. (authors)

The jet impingement cell: A valuable device for investigating CO{sub 2} corrosion

Energy Technology Data Exchange (ETDEWEB)

Kinsella, Brian; John, Douglas; Bailey, Stuart; De Marco, Roland [Western Australian Corrosion Research Group, School of Applied Chemistry, Curtin University of Technology, GPO Box U1987, Perth WA, 6845 (Australia)

2004-07-01

The jet impingement cell (JIC) is a valuable technique for the investigation of carbon dioxide corrosion of steel and its inhibition under high flow conditions or high wall shear stress. Despite the use of the JIC in corrosion testing laboratories not a great deal has been published on the design and calibration of these cells. In the evaluation of corrosion inhibitors, the type of corrosion and relative performance of the inhibitors depends on the metallurgy of the steel used to manufacture electrodes and measure the corrosion rate. This paper covers aspects of cell design and the determination of mass transfer and wall shear stress at electrodes used in the cell. The performance of different generic type corrosion inhibitors and their affect on the type of corrosion (i.e, uniform, pitting and crevice corrosion) is shown and discussed. (authors)

Study on Design Change of a Pipe Affected by Liquid Droplet Impingement Erosion

International Nuclear Information System (INIS)

Hwang, Kyeong Mo; Lee, Chan Gyu; Bhang, Keug Jin; Yim, Young Sig

2011-01-01

Liquid droplet impingement erosion (LDIE) is caused by the impact of high-velocity droplets entrained in steam or air on metal. The degradation caused by the LDIE has been experienced in steam turbine internals and high-velocity airplane components (particularly canopies). Recently, LDIE has also been observed in the pipelines of nuclear plants. LDIE among the pipelines occurs when two-phase steam experiences a high pressure drop (e.g., across an orifice in a line to the condenser). In 2011, a nuclear power plant in Korea experienced a steam leak caused by LDIE in a pipe through which a two-phase fluid was flowing. This paper describes a study on the design change of a pipe affected by LDIE in order to mitigate the damage. The design change has been reviewed in terms of fluid dynamics by using the FLUENT code

Study on Design Change of a Pipe Affected by Liquid Droplet Impingement Erosion

Energy Technology Data Exchange (ETDEWEB)

Hwang, Kyeong Mo; Lee, Chan Gyu [KEPCO Engineering and Construction Co., Daejeon (Korea, Republic of); Bhang, Keug Jin; Yim, Young Sig [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

2011-10-15

Liquid droplet impingement erosion (LDIE) is caused by the impact of high-velocity droplets entrained in steam or air on metal. The degradation caused by the LDIE has been experienced in steam turbine internals and high-velocity airplane components (particularly canopies). Recently, LDIE has also been observed in the pipelines of nuclear plants. LDIE among the pipelines occurs when two-phase steam experiences a high pressure drop (e.g., across an orifice in a line to the condenser). In 2011, a nuclear power plant in Korea experienced a steam leak caused by LDIE in a pipe through which a two-phase fluid was flowing. This paper describes a study on the design change of a pipe affected by LDIE in order to mitigate the damage. The design change has been reviewed in terms of fluid dynamics by using the FLUENT code.

Open versus arthroscopic treatment of chronic rotator cuff impingement

NARCIS (Netherlands)

Schröder, J.; van Dijk, C. N.; Wielinga, A.; Kerkhoffs, G. M.; Marti, R. K.

2001-01-01

We report the results of 238 consecutive patients who underwent in total 261 acromioplasties because of chronic rotator cuff impingement. The procedure was performed either in conventional open technique (80) or arthroscopically (181). Two years (1-10) after the operation 68% of the patients treated

Effect of a novel mobilization with movement procedure on anterolateral ankle impingement - A case report.

Science.gov (United States)

Anandkumar, Sudarshan

2018-07-01

This case report describes a 50-year-old male who presented with right anterolateral ankle pain managed unsuccessfully with rest, medications, bracing, injection, physical therapy, and massage therapy. Clinical diagnosis of anterolateral ankle impingement was based on concordant symptom reproduction with palpatory tenderness and a positive lateral synovial impingement test. This case report is a potential first time description of the successful management of anterolateral ankle impingement utilizing a novel Mulligan's mobilization with movement procedure (consisting of internal rotation of the distal tibia) and taping with immediate improvements noted in pain, range of motion, and function. The patient was seen twice a week and was discharged after four treatment sessions. A follow-up after 4 months revealed that the patient was pain free and fully functional.

Discharge characteristics and hydrodynamics behaviors of atmospheric plasma jets produced in various gas flow patterns

Science.gov (United States)

Setsuhara, Yuichi; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Koga, Kazunori; Shiratani, Masaharu

2015-09-01

Atmospheric nonequilibrium plasma jets have been widely employed in biomedical applications. For biomedical applications, it is an important issue to understand the complicated mechanism of interaction of the plasma jet with liquid. In this study, we present analysis of the discharge characteristics of a plasma jet impinging onto the liquid surface under various gas flow patterns such as laminar and turbulence flows. For this purpose, we analyzed gas flow patters by using a Schlieren gas-flow imaging system in detail The plasma jet impinging into the liquid surface expands along the liquid surface. The diameter of the expanded plasma increases with gas flow rate, which is well explained by an increase in the diameter of the laminar gas-flow channel. When the gas flow rate is further increased, the gas flow mode transits from laminar to turbulence in the gas flow channel, which leads to the shortening of the plasm-jet length. Our experiment demonstrated that the gas flow patterns strongly affect the discharge characteristics in the plasma-jet system. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

Controlled antisolvent precipitation of spironolactone nanoparticles by impingement mixing.

Science.gov (United States)

Dong, Yuancai; Ng, Wai Kiong; Shen, Shoucang; Kim, Sanggu; Tan, Reginald B H

2011-05-30

Continuous antisolvent precipitation of spironolactone nanoparticles were performed by impingement mixing in this work. In the range of Reynolds numbers (Re) 2108-6325 for the antisolvent water stream and 1771-5313 for the solvent stream, i.e. acetonic drug solution, 302-360 nm drug nanoparticles were achieved. Increasing drug concentration from 25 to 50 and 100 mg/ml led to a significant size increase from 279.0±2.6 to 302.7±4.9 and 446.0±17.3 nm, respectively. "Two-step crystallization" was first observed for spironolactone in the water/acetone system: the drug was precipitated initially as spherical cluster, which rearranged into ordered cuboidal nanocrystals finally. The nanoformulation showed faster dissolution rate in comparison with the raw drug. By combining the impingement mixing and an on-line spray drying, a fully continuous process may be developed for mass-production of dried drug nanoparticles. Copyright © 2011 Elsevier B.V. All rights reserved.

Shock and vibration protection of submerged jet impingement cooling systems: Theory and experiment

International Nuclear Information System (INIS)

Haji Hosseinloo, Ashkan; Tan, Siow Pin; Yap, Fook Fah; Toh, Kok Chuan

2014-01-01

In the recent years, advances in high power density electronics and computing systems have pushed towards more advanced thermal management technologies and higher-capacity cooling systems. Among different types of cooling systems, jet impingement technology has gained attention and been widely used in different industries for its adaptability, cooling uniformity, large heat capacity, and ease of its localization. However, these cooling systems may not function properly in dynamically harsh environment inherent in many applications such as land, sea and air transportation. In this research article, a novel double-chamber jet impingement cooling system is fabricated and its performance is studied in harsh environment. Using the authors' previous studies, isolators with optimum properties are selected to ruggedize the chassis containing the cooling chamber against shock and random vibration. Experiments are conducted on both hard-mounted and isolated chassis and the cooling performance of the system is assessed using the inlet, and impingement surface temperatures of the cooling chamber. The experimental results show the isolation system prevents any failure that otherwise would occur, and also does not compromise the thermal performance of the system. - Highlights: • A novel double-chamber jet impingement cooling system was designed and fabricated. • Comprehensive set of random vibration and shock tests are conducted. • The isolation system proved to protect the cooling system properly against mechanical failure. • Cooling system performance was not significantly affected by the input random vibration and shock

Gas turbine bucket with impingement cooled platform

Science.gov (United States)

Jones, Raphael Durand

2002-01-01

In a turbine bucket having an airfoil portion and a root portion, with a substantially planar platform at an interface between the airfoil portion and root portion, a platform cooling arrangement including at least one bore in the root portion and at least one impingement cooling tube seated in the bore, the tube extending beyond the bore with an outlet in close proximity to a targeted area on an underside of the platform.

Tissue mimicking materials for a multi-imaging modality prostate phantom

International Nuclear Information System (INIS)

D'Souza, Warren D.; Madsen, Ernest L.; Unal, Orhan; Vigen, Karl K.; Frank, Gary R.; Thomadsen, Bruce R.

2001-01-01

Materials that simultaneously mimic soft tissue in vivo for magnetic resonance imaging (MRI), ultrasound (US), and computed tomography (CT) for use in a prostate phantom have been developed. Prostate and muscle mimicking materials contain water, agarose, lipid particles, protein, Cu ++ , EDTA, glass beads, and thimerosal (preservative). Fat was mimicked with safflower oil suffusing a random mesh (network) of polyurethane. Phantom material properties were measured at 22 deg. C. (22 deg. C is a typical room temperature at which phantoms are used.) The values of material properties should match, as well as possible, the values for tissues at body temperature, 37 deg. C. For MRI, the primary properties of interest are T1 and T2 relaxations times, for US they are the attenuation coefficient, propagation speed, and backscatter, and for CT, the x-ray attenuation. Considering the large number of parameters to be mimicked, rather good agreement was found with actual tissue values obtained from the literature. Using published values for prostate parenchyma, T1 and T2 at 37 deg. C and 40 MHz are estimated to be about 1100 and 98 ms, respectively. The CT number for in vivo prostate is estimated to be 45 HU (Hounsfield units). The prostate mimicking material has a T1 of 937 ms and a T2 of 88 ms at 22 deg. C and 40 MHz; the propagation speed and attenuation coefficient slope are 1540 m/s and 0.36 dB/cm/MHz, respectively, and the CT number of tissue mimicking prostate is 43 HU. Tissue mimicking (TM) muscle differs from TM prostate in the amount of dry weight agarose, Cu ++ , EDTA, and the quality and quantity of glass beads. The 18 μm glass beads used in TM muscle increase US backscatter and US attenuation; the presence of the beads also has some effect on T1 but no effect on T2. The composition of tissue-mimicking materials developed is such that different versions can be placed in direct contact with one another in a phantom with no long term change in US, MRI, or CT

Configurable double-sided modular jet impingement assemblies for electronics cooling

Science.gov (United States)

Zhou, Feng; Dede, Ercan Mehmet

2018-05-22

A modular jet impingement assembly includes an inlet tube fluidly coupled to a fluid inlet, an outlet tube fluidly coupled to a fluid outlet, and a modular manifold having a first distribution recess extending into a first side of the modular manifold, a second distribution recess extending into a second side of the modular manifold, a plurality of inlet connection tubes positioned at an inlet end of the modular manifold, and a plurality of outlet connection tubes positioned at an outlet end of the modular manifold. A first manifold insert is removably positioned within the first distribution recess, a second manifold insert is removably positioned within the second distribution recess, and a first and second heat transfer plate each removably coupled to the modular manifold. The first and second heat transfer plates each comprise an impingement surface.

Breakup characteristics of power-law liquid sheets formed by two impinging jets

International Nuclear Information System (INIS)

Bai, Fuqiang; Diao, Hai; Chang, Qing; Wang, Endong; Du, Qing; Zhang, Mengzheng

2014-01-01

The breakup characteristics of the shear-thinning power-law liquid sheets formed by two impinging jets have been investigated with the shadowgraph technique. This paper focuses on the effects of spray parameters (jet velocity), physical parameters (viscosity) and geometry parameters (impinging angle and nozzle cross-sectional shape) on the breakup behaviors of liquid sheets. The breakup mode, sheet length and expansion angle of the sheet are extracted from the spray images obtained by a high speed camera. Impinging angle and Weber number play the similar roles in promoting the breakup of liquid sheets. With the increase of jet velocity, five different breakup modes are observed and the expansion angle increases consistently after the closed-rim mode while the sheet length first increases and then decreases. But there exists a concave consisting of a fierce drop and a second rising process on the sheet length curve for the fluid with smaller viscosity. Different nozzle cross-sectional shapes emphasize significant effects on the sheet length and expansion angle of liquid sheets. At a fixed Weber number, the liquid sheet with greater viscosity has a greater sheet length and a smaller expansion angle due to the damping effect of viscosity. (papers)

Fish impingement at estuarine power stations and its significance to commercial fishing

International Nuclear Information System (INIS)

Turnpenny, A.W.H.

1989-01-01

The abstraction of cooling water (CW) at power stations sited on tidal waters inevitably leads to mortalities of some fish which are drawn in with the CW supply and become impinged on the intake screens. These fish are predominantly 0- or 1-group juveniles which, owing to their small size, are unable to resist intake currents. Commercial fishermen often object to the fact that juvenile fish are killed in this way. Their concern stems from the fact that in order to protect stocks, commercial fishing is restricted to fish which are above a statutory minimum landing size, whereas the majority of fish killed by impingement are below this size. This Report considers the significance of impingement mortalities at four estuarine sites in Britain for six commercially important species. Life tables are used to establish expected survival trajectories for each species and to compute reproductive potential. Each fish killed on intake screens is then considered in terms of the fraction of the reproductive potential of a single adult at maturity, and is ascribed an 'adult equivalent' value. Total catches of mixed juveniles and adults are then presented as 'adult equivalent' values. (author)

Pixel signal intensity analysis of anterior cruciate ligament grafts in knees with and without intercondylar roof impingement

International Nuclear Information System (INIS)

Howell, S.M.; Berns, G.S.; Farley, T.E.; Clark, J.A.

1990-01-01

This paper determines if intercondylar roof (IR) impingement produces quantitative, regionalized, and time-dependent differences in the pixel signal intensity (PSI) of anterior cruciate ligament (ACL) grafts. Patients with hamstring autografts were placed into two groups: inpinged (n = 14) and unimpinged (n = 18). MR images were obtained at 3, 6, 9, and over 12 months after operation in the unimpinged group and at 22 months in the impinged group. The PSI was measured along the proximal, middle, and distal thirds of the graft. The PSI was greater in the impinged knees in the distal (P < .008) and middle thirds (P < .009) of the graft, but there was no difference in the proximal third. In the unimpinged group, the signal in all three zones did not change from 3 to 12 months after operation. The tibial tunnel placement was more anterior in the impinged knees (P < .001). Stability (P < .012) and knee extension (P < .003) were better in the unimpinged knees

Indirect carotid cavernous fistula mimicking ocular myasthenia.

Science.gov (United States)

Leishangthem, Lakshmi; Satti, Sudhakar Reddy

2017-10-19

71-year-old woman with progressive left-sided, monocular diplopia and ptosis. Her symptoms mimicked ocular myasthenia, but she had an indirect carotid cavernous fistula (CCF). She was diagnosed with monocular myasthenia gravis (negative acetylcholinesterase antibody) after a positive ice test and started on Mestinon and underwent a thymectomy complicated by a brachial plexus injury. Months later, she developed left-sided proptosis and ocular bruit. She was urgently referred to neuro-interventional surgery and was diagnosed with an indirect high-flow left CCF, which was treated with Onyx liquid and platinum coil embolisation. Mestinon was discontinued. Her ophthalmic symptoms resolved. However, she was left with a residual left arm and hand hemiparesis and dysmetria secondary to a brachial plexus injury. Indirect CCF usually can present with subtle and progressive symptoms leading to delayed diagnosis or misdiagnosis. It is important for ophthalmologists to consider this differential in a patient with progressive ocular symptoms. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Microjet impingement followed by scanning electron microscopy as a qualitative technique to compare cellular adhesion to various biomaterials.

Science.gov (United States)

Richards, R G; ap Gwynn, I; Bundy, K J; Rahn, B A

1995-12-01

Adhesion of cells to biomaterial surfaces is one of the major factors which mediates their biocompatibility. Quantitative or qualitative cell adhesion measurements would be useful for screening new implant materials. Microjet impingement has been evaluated by scanning electron microscopy, to determine to what extent it measures cell adhesion. The shear forces of the impingement, on the materials tested here, are seen to be greater than the cohesive strength of the cells in the impinged area, causing their rupture. The cell bodies are removed during impingement, leaving the sites of adhesion and other cellular material behind. Thus the method is shown not to provide quantification of cell adhesion forces for the metals and culture plastic tested. It is suggested that with highly adherent biomaterials, the distribution and patterns of these adhesion sites could be used for qualitative comparisons for screening of implant surfaces.

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.

A visual study of radial inward choked flow of liquid nitrogen.

Science.gov (United States)

Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.

1973-01-01

Data and high speed movies were acquired on pressurized subcooled liquid nitrogen flowing radially inward through a 0.0076 cm gap. The stagnation pressure ranged from 0.7 to 4 MN/sq m. Steady radial inward choked flow appears equivalent to steady choked flow through axisymmetric nozzles. Transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets. The critical mass flow rate data for the transient case appear different from those for the steady case. On the mass flow rate vs pressure map, the slope and separation of the isotherms appear to be less for transient than for steady radial choked flow.

"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.

Temperature-field measurements of a premixed butane/air circular impinging-flame using reference-beam interferometry

International Nuclear Information System (INIS)

Qi, J.A.; Leung, C.W.; Wong, W.O.; Probert, S.D.

2006-01-01

Reference-beam interferometry (RBI) was applied to study the axisymmetric temperature fields of a small-scale, low Reynolds-number, low-pressure and fuel-rich premixed butane/air circular-flame jet, when it was impinging vertically upwards onto a horizontal copper plate. By maintaining a Reynolds number, Re, of 500 and an equivalence ratio, φ, of 1.8, interferograms of the impinging-flame jet were obtained for various nozzle-to-plate-distances. Temperature fields of the flame were then determined using the inverse Abel transformation from the obtained interferograms. Temperatures at several locations were measured experimentally with a T-type thermocouple: they were used as a reference to help in the determination as well as the validation. In the present study, a non-contact method has been successfully developed to measure the temperature fields of a circular impinging gas-fired flame jet

IMPINGEMENT-SYNDROME OF PERONEUS BREVIS TENDON AFTER CALCANEAL FRACTURES (MORPHOLOGICAL ASPECTS

Directory of Open Access Journals (Sweden)

N. S. Konovalchuk

2017-01-01

Full Text Available Background. One of the main causes of pain in patients with consequences of calcaneal fractures is the lateral impingement syndrome. This term means lateral displacement of outer calcaneal wall at the moment of fracture, narrowing of anatomical space under the lateral malleolus and compression of soft tissues in this region, including tendons of short and long peroneal muscles. This leads to chronic traumatization of tendons, alteration of their normal tracking and development of tendinitis and tenosynovitis. At this moment there are no articles in foreign or Russian literature describing how prolonged traumatization influences the internal structure of the tendons. The purpose of this study was to evaluate the morphological changes in structure of peroneus brevis tendon after different duration of compression between outer wall of calcaneus and the tip of the lateral malleolus in patients with calcaneal malunion.Materials and methods. Fifteen patients with calcaneal malunion and lateral impingement syndrome were treated operatively between 2016 and 2017. To confirm the lateral impingement syndrome, the authors performed clinical examination and AP x-rays of ankle joint. Two peroneus brevis tendon specimens were obtained intraoperatively in each of 15 patients: one specimen from compressed and one from non-compressed area. Obtained specimens were histologically examined according to standard protocol.Results. Microscopically all specimens showed separation of collagen bundles with loose connective tissue degeneration, increase of vascularization and inflammation. The degree of these changes differed according to the compression duration. This allowed us to analyze the dynamics of these changes.Conclusion. The morphological changes in structure of peroneus brevis tendon during the compression between outer wall of calcaneus and the tip of the lateral malleolus correspond with dynamics of common pathologic reactions. Early stages showed signs of

Multiple hereditary exostoses and ischiofemoral impingement: a case-control study

International Nuclear Information System (INIS)

Yoong, Philip; Mansour, Ramy; Teh, James L.

2014-01-01

To assess whether there is a significant difference in the ischiofemoral space in patients with multiple hereditary exostoses affecting the proximal femora compared to normal patients. Ischiofemoral impingement is an increasingly recognized cause of hip and buttock pain. This causes narrowing of the ischiofemoral space resulting in an abnormal quadratus femoris muscle. We performed a retrospective search for individuals with MHE with proximal femoral involvement on pelvic MRI over a 7-year period (2006-2013). Suitable patients were age- and sex-matched with a control group. The minimum ischiofemoral space (MIFS) was recorded in each hip, as was the presence of edema and atrophy of quadratus femoris and concomitant hip osteoarthrosis. MRI features suggestive of ischiofemoral impingement were defined as MIFS less than 10 mm or an abnormal quadratus femoris muscle. Twenty-one hips in 11 individuals with MHE were included in the study. A total of 42 hips were analyzed. The mean age was 37 years (range, 13-72 years) and 55 % were male. There was a significant difference (p < 0.05) in the MIHS in individuals with MHE (mean, 10.7 mm, range, 0-21 mm) compared to a control group (mean, 18.1 mm, range, 10.5-26.5 mm). MRI features suggestive of ischiofemoral impingement were seen in 13/21 (62 %) hips in the MHE group and 0/21 (0 %) in the control group. The reduced ischiofemoral space and associated quadratus femoris abnormalities in patients with MHE involving the proximal femora may account for hip/buttock symptoms in the absence of significant degenerative change. (orig.)

Multiple hereditary exostoses and ischiofemoral impingement: a case-control study

Energy Technology Data Exchange (ETDEWEB)

Yoong, Philip; Mansour, Ramy; Teh, James L. [Nuffield Orthopaedic Centre, Department of Radiology, Oxford (United Kingdom)

2014-09-15

To assess whether there is a significant difference in the ischiofemoral space in patients with multiple hereditary exostoses affecting the proximal femora compared to normal patients. Ischiofemoral impingement is an increasingly recognized cause of hip and buttock pain. This causes narrowing of the ischiofemoral space resulting in an abnormal quadratus femoris muscle. We performed a retrospective search for individuals with MHE with proximal femoral involvement on pelvic MRI over a 7-year period (2006-2013). Suitable patients were age- and sex-matched with a control group. The minimum ischiofemoral space (MIFS) was recorded in each hip, as was the presence of edema and atrophy of quadratus femoris and concomitant hip osteoarthrosis. MRI features suggestive of ischiofemoral impingement were defined as MIFS less than 10 mm or an abnormal quadratus femoris muscle. Twenty-one hips in 11 individuals with MHE were included in the study. A total of 42 hips were analyzed. The mean age was 37 years (range, 13-72 years) and 55 % were male. There was a significant difference (p < 0.05) in the MIHS in individuals with MHE (mean, 10.7 mm, range, 0-21 mm) compared to a control group (mean, 18.1 mm, range, 10.5-26.5 mm). MRI features suggestive of ischiofemoral impingement were seen in 13/21 (62 %) hips in the MHE group and 0/21 (0 %) in the control group. The reduced ischiofemoral space and associated quadratus femoris abnormalities in patients with MHE involving the proximal femora may account for hip/buttock symptoms in the absence of significant degenerative change. (orig.)

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.

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.

Two or more impingement and/or instability deformities are often present in patients with hip pain.

Science.gov (United States)

Tibor, Lisa M; Liebert, Gunnar; Sutter, Reto; Impellizzeri, Franco M; Leunig, Michael

2013-12-01

Damage to the hip can occur due to impingement or instability caused by anatomic factors such as femoral and acetabular version, neck-shaft angle, alpha angle, and lateral center-edge angle (CEA). The associations between these anatomic factors and how often they occur in a painful hip are unclear but if unaddressed might explain failed hip preservation surgery. We determined (1) the influence of sex on the expression of impingement-related or instability-related factors, (2) the associations among these factors, and (3) how often both impingement and/or instability factors occur in the same hip. We retrospectively reviewed a cohort of 170 hips (145 patients) undergoing MR arthrography of the hip for any reason. We excluded 58 hips with high-grade dysplasia, Perthes' sequelae, previous surgery, or incomplete radiographic information, leaving 112 hips (96 patients). We measured femoral version and alpha angles on MR arthrograms. Acetabular anteversion, lateral CEA, and neck-shaft angle were measured on pelvic radiographs. We observed a correlation between sex and alpha angle. Weak or no correlations were observed between the other five parameters. In 66% of hips, two or more (of five) impingement parameters, and in 51% of hips, two or more (of five) instability parameters were found. Patients with hip pain frequently have several anatomic factors potentially contributing to chondrolabral damage. To address pathologic hip loading due to impingement and/or instability, all of the anatomic influences should be known. As we found no associations between anatomic factors, we recommend an individualized assessment of each painful hip.

Physical examination tests for the diagnosis of femoroacetabular impingement. A systematic review.

Science.gov (United States)

Pacheco-Carrillo, Aitana; Medina-Porqueres, Ivan

2016-09-01

Numerous clinical tests have been proposed to diagnose FAI, but little is known about their diagnostic accuracy. To summarize and evaluate research on the accuracy of physical examination tests for diagnosis of FAI. A search of the PubMed, SPORTDiscus and CINAHL databases was performed. Studies were considered eligible if they compared the results of physical examination tests to those of a reference standard. Methodological quality and internal validity assessment was performed by two independent reviewers using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. The systematic search strategy revealed 298 potential articles, five of which articles met the inclusion criteria. After assessment using the QUADAS score, four of the five articles were of high quality. Clinical tests included were Impingement sign, IROP test (Internal Rotation Over Pressure), FABER test (Flexion-Abduction-External Rotation), Stinchfield/RSRL (Resisted Straight Leg Raise) test, Scour test, Maximal squat test, and the Anterior Impingement test. IROP test, impingement sign, and FABER test showed the most sensitive values to identify FAI. The diagnostic accuracy of physical examination tests to assess FAI is limited due to its heterogenecity. There is a strong need for sound research of high methodological quality in this area. Copyright © 2016 Elsevier Ltd. All rights reserved.

Invasive Aspergillosis Mimicking Metastatic Lung Cancer

Directory of Open Access Journals (Sweden)

Michiel J. E. G. W. Vanfleteren

2018-06-01

Full Text Available In a patient with a medical history of cancer, the most probable diagnosis of an 18FDG-avid pulmonary mass combined with intracranial abnormalities on brain imaging is metastasized cancer. However, sometimes a differential diagnosis with an infectious cause such as aspergillosis can be very challenging as both cancer and infection are sometimes difficult to distinguish. Pulmonary aspergillosis can present as an infectious pseudotumour with clinical and imaging characteristics mimicking lung cancer. Even in the presence of cerebral lesions, radiological appearance of abscesses can look like brain metastasis. These similarities can cause significant diagnostic difficulties with a subsequent therapeutic delay and a potential adverse outcome. Awareness of this infectious disease that can mimic lung cancer, even in an immunocompetent patient, is important. We report a case of a 65-year-old woman with pulmonary aspergillosis disseminated to the brain mimicking metastatic lung cancer.

Impingement studies at the 100-N reactor water intake

International Nuclear Information System (INIS)

Page, T.L.; Neitzel, D.A.; Gray, R.H.

1977-09-01

Fish impingement and traveling screen passage were studied at the 100-N reactor water intake structure, Columbia River mile 380, from late April to August 1977. Species and numbers of fish affected were determined and compared to those at the adjacent Hanford Generating Project (HGP). Fish protection procedures previously developed for HGP were evaluated for application at 100-N

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.

A Comparative Analysis of Ability of Mimicking Portfolios in Representing the Background Factors

OpenAIRE

Asgharian, Hossein

2004-01-01

Our aim is to give a comparative analysis of ability of different factor mimicking portfolios in representing the background factors. Our analysis contains a cross-sectional regression approach, a time-series regression approach and a portfolio approach for constructing factor mimicking portfolios. The focus of the analysis is the power of mimicking portfolios in the asset pricing models. We conclude that the time series regression approach, with the book-to-market sorted portfolios as the ba...

Impact of entrainment and impingement on fish populations in the Hudson River Estuary. Volume II. Impingement impact analyses, evaluations of alternative screening devices, and critiques of utility testimony relating to density-dependent growth, the age-composition of the striped bass spawning stock, and the LMS real-time life cycle model

International Nuclear Information System (INIS)

Barnthouse, L.W.; Van Winkle, W.; Golumbek, J.; Cada, G.F.; Goodyear, C.P.; Christensen, S.W.; Cannon, J.B.; Lee, D.W.

1982-04-01

This volume includes a series of four exhibits relating to impacts of impingement on fish populations, together with a collection of critical evaluations of testimony prepared for the utilities by their consultants. The first exhibit is a quantitative evaluation of four sources of bias (collection efficiency, reimpingement, impingement on inoperative screens, and impingement survival) affecting estimates of the number of fish killed at Hudson River power plants. The two following exhibits contain, respectively, a detailed assessment of the impact of impingement on the Hudson River white perch population and estimates of conditional impingement mortality rates for seven Hudson River fish populations. The fourth exhibit is an evaluation of the engineering feasibility and potential biological effectiveness of several types of modified intake structures proposed as alternatives to cooling towers for reducing impingement impacts. The remainder of Volume II consists of critical evaluations of the utilities' empirical evidence for the existence of density-dependent growth in young-of-the-year striped bass and white perch, of their estimate of the age-composition of the striped bass spawning stock in the Hudson River, and of their use of the Lawler, Matusky, and Skelly (LMS) Real-Time Life Cycle Model to estimate the impact of entrainment and impingement on the Hudson River striped bass population

Effect of coating material on heat transfer and skin friction due to impinging jet onto a laser producedhole

Science.gov (United States)

Shuja, S. Z.; Yilbas, B. S.

2013-07-01

Jet impingement onto a two-layer structured hole in relation to laser drilling is investigated. The hole consists of a coating layer and a base material. The variations in the Nusselt number and the skin friction are predicted for various coating materials. The Reynolds stress turbulent model is incorporated to account for the turbulence effect of the jet flow and nitrogen is used as the working fluid. The study is extended to include two jet velocities emanating from the conical nozzle. It is found that coating material has significant effect on the Nusselt number variation along the hole wall. In addition, the skin friction varies considerably along the coating thickness in thehole.

Subacute posteromedial impingement of the ankle in athletes: MR imaging evaluation and ultrasound guided therapy

International Nuclear Information System (INIS)

Messiou, Christina; Robinson, Philip; O'Connor, Philip J.; Grainger, Andrew

2006-01-01

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.)

Simulation of aerosol flow interaction with a solid body on molecular level

Science.gov (United States)

Amelyushkin, Ivan A.; Stasenko, Albert L.

2018-05-01

Physico-mathematical models and numerical algorithm of two-phase flow interaction with a solid body are developed. Results of droplet motion and its impingement upon a rough surface in real gas boundary layer simulation on the molecular level obtained via molecular dynamics technique are presented.

Cam Femoroacetabular Impingement as a Possible Explanation of Recalcitrant Anterior Knee Pain.

Science.gov (United States)

Sanchis-Alfonso, Vicente; Tey, Marc; Monllau, Joan Carles

2016-01-01

We present a case of a patient with chronic anterior knee pain (AKP) recalcitrant to conservative treatment who returned to our office for severe hip pain secondary to Cam femoroacetabular impingement (Cam FAI) at 10 months after the onset of knee pain. This case highlights the fact that the main problem is not in the patella but in the hip in some patients with AKP. We hypothesize that there is an external femoral rotation in order to avoid the impingement and therefore the hip pain in patients with Cam FAI. This functional femoral rotation could provoke a patellofemoral imbalance that may be, in theory, responsible for patellofemoral pain in this particular patient. In our case, Cam FAI resolution was related to the resolution of AKP.

Numerical analysis of jet impingement heat transfer at high jet Reynolds number and large temperature difference

DEFF Research Database (Denmark)

Jensen, Michael Vincent; Walther, Jens Honore

2013-01-01

was investigated at a jet Reynolds number of 1.66 × 105 and a temperature difference between jet inlet and wall of 1600 K. The focus was on the convective heat transfer contribution as thermal radiation was not included in the investigation. A considerable influence of the turbulence intensity at the jet inlet...... to about 100% were observed. Furthermore, the variation in stagnation point heat transfer was examined for jet Reynolds numbers in the range from 1.10 × 105 to 6.64 × 105. Based on the investigations, a correlation is suggested between the stagnation point Nusselt number, the jet Reynolds number......, and the turbulence intensity at the jet inlet for impinging jet flows at high jet Reynolds numbers. Copyright © 2013 Taylor and Francis Group, LLC....

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.

Time-resolved large-scale volumetric pressure fields of an impinging jet from dense Lagrangian particle tracking

Science.gov (United States)

Huhn, F.; Schanz, D.; Manovski, P.; Gesemann, S.; Schröder, A.

2018-05-01

Time-resolved volumetric pressure fields are reconstructed from Lagrangian particle tracking with high seeding concentration using the Shake-The-Box algorithm in a perpendicular impinging jet flow with exit velocity U=4 m/s (Re˜ 36,000) and nozzle-plate spacing H/D=5. Helium-filled soap bubbles are used as tracer particles which are illuminated with pulsed LED arrays. A large measurement volume has been covered (cloud of tracked particles in a volume of 54 L, ˜ 180,000 particles). The reconstructed pressure field has been validated against microphone recordings at the wall with high correlation coefficients up to 0.88. In a reduced measurement volume (13 L), dense Lagrangian particle tracking is shown to be feasable up to the maximal possible jet velocity of U=16 m/s.

Experimental investigation of the velocity distribution of the attached plane jet after impingement with the corner in a high room

Energy Technology Data Exchange (ETDEWEB)

Cao, Guangyu [Department of Energy Technology, Helsinki University of Technology, Otakaari 4, 02150 Espoo (Finland); Ruponen, Mika [Halton Oy, Haltonintie 1-3, 47400 Kausala (Finland); Kurnitski, Jarek [Finnish Innovation Fund, Itaemerentori 2, 00181 Helsinki (Finland)

2010-06-15

Supplying air into rooms properly without causing a sensation of draught is a challenging task. Airflow patterns and the air velocity of attached plane jets should be predicted and designed accurately before the airflow enters an occupied zone in different applications. The objective of this study is to identify the airflow patterns of attached plane jets and set up an efficient model to predict the maximum jet velocity decay of an attached plane jet after its impingement with the corner in a high room. A full-scale test chamber was used to measure the jet velocity with a plane jet supply device. The attached plane jet is bounded initially by the ceiling and the insulated wall after being discharged from the jet slot. Three velocities from the slot, 0.5, 1.0, and 2.0 m/s, are used as the initial jet velocities with three Reynolds numbers, 1000, 2000, and 4000, respectively. The results show that the behaviours of the attached plane jet differ from earlier studies carried out in a relatively low room. The virtual origin model setup in this study can be used to predict the maximum jet velocity decay for jet flow design with impingement in the corners of rooms. (author)

Oblique radiograph for the detection of bone spurs in anterior ankle impingement

International Nuclear Information System (INIS)

Dijk, Niek C. van; Wessel, Ronald N.; Tol, Johannes L.; Maas, M.

2002-01-01

Objective: The aim of this study was to develop a radiographic view to detect anteromedial talotibial osteophytes that remain undetected on standard radiographs. Design and patients: In 10 cadaver specimens the maximal size was measured of anteromedial tibial osteophytes that remain undetected on a standard lateral radiograph projection, due to the presence of the anteromedial tibial rim. The average projection of the most prominent anterolateral tibial rim over the anteromedial rim was found to be 7.3 mm. A 7 mm barium-clay osteophyte was attached to this anteromedial rim of the distal tibia. Anteromedial osteophytes become most prominent on an oblique view, in which the radiographic beam is tilted into a 45 craniocaudal direction with the leg in 30 external rotation. This oblique view was compared with the findings of arthroscopic surgery in 25 consecutive patients with anterior ankle impingement syndrome. Results: Medially located tibial and talar osteophytes remained undetected on a standard lateral projection and became visible on the oblique anteromedial impingement (AMI) radiograph. Anterolateral tibial and talar osteophytes were well detected on a standard lateral radiograph projection but were invisible on the AMI view. There was a high correlation between the location of the osteophyte and the location of symptoms and the findings at arthroscopy. Conclusion: A combination of lateral and oblique radiographs can be used to differentiate between anteromedial and anterolateral bony ankle impingement. (orig.)

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.

Development of iodine based impinger solutions for the efficient capture of Hg{sup 0} using direct injection nebulization-inductively coupled plasma mass spectrometry analysis

Energy Technology Data Exchange (ETDEWEB)

Hedrick, E.; Lee, T.G.; Biswas, P.; Zhuang, Y. [US Environmental Protection Agency, Cincinnati, OH (USA). National Exposure Research Laboratory

2001-09-15

Inductively coupled plasma mass spectrometry (ICP/MS) with direct injection nebulization (DIN) was used to evaluate novel impinger solution compositions capable of capturing elemental mercury (Hg{sup 0}) in EPA Method 5 type sampling. An iodine based impinger solution proved to be very efficient for Hg{sup 0} capture and was amenable to direct analysis by DIN-ICP/MS. Hg{sup 0} capture efficiency using aqueous iodine (I{sub 3}{sup -}) was comparable to Hg{sup 0} capture using acidified potassium permanganate impinger solutions which were analyzed by cold vapor atomic absorption spectrometry (CVAAS) with greater than 98% capture of Hg{sup 0} in the oxidizing impinger. Using DIN-ICP/MS, it was demonstrated for the first time that iodine can be generated just prior to impinger sampling for efficiently oxidizing Hg{sup 0} and retailing it in solution as HgI{sub 4}{sup 2-}. Due to the increased interest in Hg speciation from combustion sources and the potential for using DIN-ICP/MS for multiple metals analyses, an impinger sampling train for gaseous Hg speciation and multiple metals analyses using DIN-ICP/MS analyses is presented. The unique feature of such a sampling train is that each impinger solution in the series is amenable to direct analysis by DIN-ICP/MS. A bituminous coal was combusted in a bench scale coal system, and gaseous Hg species (oxidized and elemental) were determined using the proposed impinger train. The DIN-ICP/Ms instrumental detection limit was 0.003 ppb, and MDLs ranged from 0.007 to 0.116 {mu}g/L (ppb) in a variety of impinger solutions used for Hg capture. 33 refs., 5 figs., 7 tabs.

The importance of bony impingement in restricting flexion after total knee arthroplasty: computer simulation model with clinical correlation.

Science.gov (United States)

Mizu-Uchi, Hideki; Colwell, Clifford W; Fukagawa, Shingo; Matsuda, Shuichi; Iwamoto, Yukihide; D'Lima, Darryl D

2012-10-01

We constructed patient-specific models from computed tomography data after total knee arthroplasty to predict knee flexion based on implant-bone impingement. The maximum flexion before impingement between the femur and the tibial insert was computed using a musculoskeletal modeling program (KneeSIM; LifeModeler, Inc, San Clemente, California) during a weight-bearing deep knee bend. Postoperative flexion was measured in a clinical cohort of 21 knees (low-flex group: 6 knees with 125° of flexion at 2 years). Average predicted flexion angles were within 2° of clinical measurements for the high-flex group. In the low-flex group, 4 cases had impingement involving the bone cut at the posterior condyle, and the average predicted knee flexion was 102° compared with 93° measured clinically. These results indicate that the level of the distal femoral resection should be carefully planned and that exposed bone proximal to the tips of the posterior condyles of the femoral component should be removed if there is risk of impingement. Copyright © 2012 Elsevier Inc. All rights reserved.

Mimicking the Interfacial Dynamics of Flowing White Blood Cells

Science.gov (United States)

Santore, Maria

2015-03-01

The rolling of particles on surfaces, facilitated by hydrodynamic forces combined with localized surface interactions of the appropriate strengths, spatial arrangements, and ranges, is a technologically useful means of transporting and manipulating particles. One's intuition for the rolling of a marble or a car tire cannot be extrapolated down to microparticle length scales because the microparticle interactions are dominated by electrostatic, van der Waals, and hydrogen bonding interactions rather than a friction that depends on an imposed normal force. Indeed, our microparticle rolling systems are inspired by the rolling of white blood cells on the inner walls of venules as part of the innate immune response: Selectin molecules engage with their counterparts on the opposing surfaces to slow cell motion relative to that for freely flowing cells. In the resulting rolling signature, ligand-receptor binding and crack closing on the front of the cell are balanced with molecular dis-bonding and crack opening at the rear. The contact region is relatively static, allowing other interactions (for instance signaling) to occur for a finite duration. Thus, achieving particle rolling in synthetic systems is important because it facilitates particle-surface interactions in a continuous nonfouling fashion where the contact surface is continually renewed. In developing a synthetic model for this system, we employ polymers to modify flowing particles and /or planar collectors, producing heterogeneous interfaces which can support rolling or produce other motion signatures such as skipping, arrest, or free flow. We identify, in the synthetic system, combinations of variables that produce rolling and demonstrate how the distinction between rolling and arrest is not a simple matter of the adhesion strength between the particles and the collector. Rolling is a cooperative process and the coordination of binding in one location with dis-bonding in another requires appropriate length

Novel two-phase jet impingement heat sink for active cooling of electronic devices

International Nuclear Information System (INIS)

Oliveira, Pablo A. de; Barbosa, Jader R.

2017-01-01

Highlights: • Novel jet-based heat sink integrates the evaporator and the expansion device. • The system was tested with a small-scale oil-free R-134a compressor. • The thermodynamic performance of the cooling system was evaluated experimentally. • The single-jet maximum cooling capacity was 160 W, with a COP of 2.3 and a η 2nd of 8%. • Maximum heat transfer coefficient of 15 kW m −2 K −1 and surface temperature of 30 °C. - Abstract: This work presents a compact vapor compression cooling system equipped with a small-scale oil-free R-134a compressor and a jet-impingement-based heat sink that integrates the evaporator and the expansion device into a single unit. At the present stage of the development, a single orifice was used to generate the high-speed two-phase impinging jet on the heated surface. The effects of the compressor piston stroke, applied thermal load and orifice diameter on the system performance were quantified. The thermodynamic performance of the system was evaluated in terms of the temperature of the heated surface, impinging jet heat transfer coefficient, several system thermal resistances, coefficient of performance, second-law efficiency and second-law ratio. The coefficient of performance of the new refrigeration system increased with the cooling capacity, justifying its application in the removal of large thermal loads. The maximum system cooling capacity with a single jet was approximately 160 W, which was achieved with an orifice diameter of 500 μm and operation at a full compressor piston stroke. This condition corresponded to a COP of 2.3, a second-law efficiency of 8.0%, a jet impingement heat transfer coefficient above 15 kW m −2 K −1 and a heater surface temperature of approximately 30 °C.

Self-induced oscillation of free surface in a tank with circulating flow, 2

International Nuclear Information System (INIS)

Okamoto, Koji; Madarame, Haruki; Hagiwara, Tsuyoshi

1991-01-01

An energy supply mechanism to self-induced sloshing in a tank with circulating flow is proposed. The circulating flow impinges on the free surface making it swell partially. The amount of swell increases with increasing water level under the condition of growing sloshing. The change of the free surface contour by this effect supplies sufficient energy to the sloshing. The dependency of the sloshing growth on the flow rate and the water level is explained well by this model. (author)

Arthroscopic treatment of impingement of the ankle reduces pain and enhances function

DEFF Research Database (Denmark)

Rasmussen, S; Hjorth Jensen, C

2002-01-01

A consecutive series of 105 patients with a median age of 35 (16-62) years who were operated on with arthroscopic resection for impingement of the ankle using standardized technique without distraction is presented. All patients complained of painful dorsiflexion and had failed to respond to cons...... synovectomy and intravenous antibiotics. In one patient persistent symptoms were recorded. Ankle arthroscopy yielded good results in the treatment of anterior impingement of the ankle as it effectively reduced pain and enhanced function....... of pain. Gait was improved in 30/41 patients and 22 resumed sporting activities. The results were graded excellent in 67, good in 25, fair in six and poor in seven patients. There were four deep infections and one synovial fistula in this series. The deep infections all responded well to arthroscopic...

Cam Femoroacetabular Impingement as a Possible Explanation of Recalcitrant Anterior Knee Pain

Directory of Open Access Journals (Sweden)

Vicente Sanchis-Alfonso

2016-01-01

Full Text Available We present a case of a patient with chronic anterior knee pain (AKP recalcitrant to conservative treatment who returned to our office for severe hip pain secondary to Cam femoroacetabular impingement (Cam FAI at 10 months after the onset of knee pain. This case highlights the fact that the main problem is not in the patella but in the hip in some patients with AKP. We hypothesize that there is an external femoral rotation in order to avoid the impingement and therefore the hip pain in patients with Cam FAI. This functional femoral rotation could provoke a patellofemoral imbalance that may be, in theory, responsible for patellofemoral pain in this particular patient. In our case, Cam FAI resolution was related to the resolution of AKP.

Effect of wall impingement on ambient gas entrainment, fuel evaporation and mixture formation of diesel spray

Energy Technology Data Exchange (ETDEWEB)

Nishida, Keiya [Department of Mechanical Physics Engineering, University of Hiroshima (Japan); Matsumoto, Yuhei; Zhang, Wu [Mazda Motor Corp. (Japan); Gao, Jian [University of Wisconsin (United States); Moon, Seoksu [Argonne National Laboratory (United States)

2010-07-01

In the energy sector, with the implementation of stringent regulations on combustion emissions and the depletion of conventional fuels, there is a pressing need to improve the performance of engines. The purpose of this paper is to determine the impact of wall impingement on several characteristics of diesel spray. Experiments were carried out with both a small and a large amount of diesel spray injected and ambient gas entrainment, fuel evaporation and mixture formation were evaluated using an LAS optical system. Results showed that wall impingement has the same effects for small or large amounts of diesel spray injected; these are: a larger volume spray after the impingement and a smaller volume after it, the suppression of ambient gas entrainment and fuel evaporation, and the shift of the PDF peak of the vapor equivalent ratio. This study provided useful information but further work is needed to address the remaining issues.

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.

Leiomyoma of the distal oesophagus mimicking achalasia

NARCIS (Netherlands)

Idenburg, F. J.; Akkermans, L. M.; Smout, A. J.; Kooijman, C. D.; Obertop, H.

1991-01-01

An unusual case of a patient with symptoms suggestive of oesophageal achalasia is described. Most oesophageal tumour growths causing secondary achalasia are associated with malignant tumours. This patient had a large oesophageal leiomyoma closely mimicking achalasia. Treatment consisted of

Etiology of the anterior ankle impingement syndrome: A descriptive anatomical study

NARCIS (Netherlands)

Tol, Johannes L.; van Dijk, C. Niek

2004-01-01

Background: In the anterior ankle impingement syndrome, recurrent traction to the anterior joint capsule is stated to be the cause of formation of talotibial osteophytes. This hypothesis involves the assumption that the osteophytes originate at the site where a capsular attachment is located. A soft

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.

The Natural History of Femoroacetabular Impingement

Directory of Open Access Journals (Sweden)

Benjamin D. Kuhns

2015-11-01

Full Text Available Femoroacetabular impingement (FAI is a clinical syndrome resulting from abnormal hip joint morphology and is a common cause of hip pain in young adults. FAI has been posited as a precursor to hip osteoarthritis, however, conflicting evidence exists and the true natural history of the disease is unclear. The purpose of this article is to review the current understanding of how FAI damages the hip joint by highlighting its pathomechanics and etiology. We then review the current evidence relating FAI to osteoarthritis. Lastly, we will discuss the potential of hip preservation surgery to alter the natural history of FAI, reduce the risk of developing osteoarthritis and the need for future arthroplasty.

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...

Visualization and mass transfer with a bistable two-slot impinging jet

Czech Academy of Sciences Publication Activity Database

Trávníček, Zdeněk; Maršík, František

2003-01-01

Roč. 6, č. 4 (2003), s. 337-441 ISSN 1343-8875 R&D Projects: GA AV ČR IAA2076203 Institutional research plan: CEZ:AV0Z2076919 Keywords : visualization * mass transfer * impinging jet Subject RIV: BK - Fluid Dynamics Impact factor: 0.279, year: 2002

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.

Preoperative physical examination and imaging of femoroacetabular impingement prior to hip arthroscopy-a systematic review.

Science.gov (United States)

Haldane, Chloe E; Ekhtiari, Seper; de Sa, Darren; Simunovic, Nicole; Ayeni, Olufemi R

2017-08-01

The purpose of this systematic review is to report current preoperative assessment for femoroacetabular impingement (FAI) including physical examination and imaging modalities prior to hip arthroscopy, and report current imaging measures used in the diagnosis of FAI. The electronic databases MEDLINE, EMBASE and PubMed were searched and screened in duplicate for relevant studies. Data regarding patient demographics, non-operative treatment, preoperative assessment including physical examination and imaging prior to hip arthroscopy were abstracted. Study quality was assessed in duplicate using the Methodological Index for Non-Randomized Studies criteria. Sixty-eight studies of fair quality evidence that involved a total of 5125 patients (5400 hips) were included. In total, 56% of all patients were male and mean age was 36 years (SD ± 10.0). Within physical examination, FADIR impingement testing was reported in 57% of patients. All included studies reported plain radiographic imaging as a component of preoperative assessment with anterior-posterior pelvis view being the most commonly reported view, followed by the cross-table lateral and Dunn views. Magnetic resonance imaging was obtained for 52% of included patients and computed tomography for 26% of patients. The most commonly reported measure within imaging for the diagnosis of cam type impingement was alpha angle (66%), whereas for pincer type impingement, the cross-over sign (48%) was most reported. Preoperative assessment is underreported in the FAI literature. Improved reporting is warranted to develop a more consistent and validated diagnostic algorithm for FAI to enhance patient selection. Level of evidence : Level IV, Systematic Review of Level I-IV Studies.

Preoperative physical examination and imaging of femoroacetabular impingement prior to hip arthroscopy—a systematic review

Science.gov (United States)

Haldane, Chloe E.; Ekhtiari, Seper; de SA, Darren; Simunovic, Nicole

2017-01-01

Abstract The purpose of this systematic review is to report current preoperative assessment for femoroacetabular impingement (FAI) including physical examination and imaging modalities prior to hip arthroscopy, and report current imaging measures used in the diagnosis of FAI. The electronic databases MEDLINE, EMBASE and PubMed were searched and screened in duplicate for relevant studies. Data regarding patient demographics, non-operative treatment, preoperative assessment including physical examination and imaging prior to hip arthroscopy were abstracted. Study quality was assessed in duplicate using the Methodological Index for Non-Randomized Studies criteria. Sixty-eight studies of fair quality evidence that involved a total of 5125 patients (5400 hips) were included. In total, 56% of all patients were male and mean age was 36 years (SD ± 10.0). Within physical examination, FADIR impingement testing was reported in 57% of patients. All included studies reported plain radiographic imaging as a component of preoperative assessment with anterior–posterior pelvis view being the most commonly reported view, followed by the cross-table lateral and Dunn views. Magnetic resonance imaging was obtained for 52% of included patients and computed tomography for 26% of patients. The most commonly reported measure within imaging for the diagnosis of cam type impingement was alpha angle (66%), whereas for pincer type impingement, the cross-over sign (48%) was most reported. Preoperative assessment is underreported in the FAI literature. Improved reporting is warranted to develop a more consistent and validated diagnostic algorithm for FAI to enhance patient selection. Level of evidence: Level IV, Systematic Review of Level I–IV Studies. PMID:28948032

Impingement syndrome of the shoulder following double row suture anchor technique for arthroscopic rotator cuff repair: a case report

Directory of Open Access Journals (Sweden)

Rambani Rohit

2009-06-01

Full Text Available Abstract Introduction Arthroscopic repair of the rotator cuff is a demanding surgery. Accurate placement of anchors is key to success. Case presentation A 38-year-old woman received arthroscopic repair of her rotator cuff using a double row suture anchor technique. Postoperatively, she developed impingement syndrome which resulted from vertical displacement of a suture anchor once the shoulder was mobilised. The anchor was removed eight weeks following initial surgery and the patient had an uneventful recovery. Conclusion Impingement syndrome following arthroscopic repair of the rotator cuffs using double row suture anchor has not been widely reported. This is the first such case where anchoring has resulted in impingement syndrome.

Measurement of guided mode wavenumbers in soft tissue–bone mimicking phantoms using ultrasonic axial transmission

International Nuclear Information System (INIS)

Chen Jiangang; Su Zhongqing; Cheng Li; Foiret, Josquin; Minonzio, Jean-Gabriel; Talmant, Maryline; Laugier, Pascal

2012-01-01

Human soft tissue is an important factor that influences the assessment of human long bones using quantitative ultrasound techniques. To investigate such influence, a series of soft tissue–bone phantoms (a bone-mimicking plate coated with a layer of water, glycerol or silicon rubber) were ultrasonically investigated using a probe with multi-emitter and multi-receiver arrays in an axial transmission configuration. A singular value decomposition signal processing technique was applied to extract the frequency-dependent wavenumbers of several guided modes. The results indicate that the presence of a soft tissue-mimicking layer introduces additional guided modes predicted by a fluid waveguide model. The modes propagating in the bone-mimicking plate covered by the soft-tissue phantom are only slightly modified compared to their counterparts in the free bone-mimicking plate, and they are still predicted by an elastic transverse isotropic two-dimensional waveguide. Altogether these observations suggest that the soft tissue–bone phantoms can be modeled as two independent waveguides. Even in the presence of the overlying soft tissue-mimicking layer, the modes propagating in the bone-mimicking plate can still be extracted and identified. These results suggest that our approach can be applied for the purpose of the characterization of the material and structural properties of cortical bone. (paper)

Schwannoma of the left brachial plexus mimicking a ...

African Journals Online (AJOL)

Schwannoma of the left brachial plexus mimicking a cervicomediastinal ... Her voice was hoarse but there was no eye signs suggestive of thyrotoxicosis. ... A presumptive diagnosis of thyroid carcinoma with retrosternal extension was made.

Characteristics of compressed natural gas jet and jet-wall impingement using the Schlieren imaging technique

International Nuclear Information System (INIS)

Ismael, M A; Heikal, M R; Baharom, M B

2013-01-01

An experimental study was performed to investigate the compressed natural gas jet characteristics and jet-wall impingement using the Schlieren imaging technique and image processing. An injector driver was used to drive the natural gas injector and synchronized with camera triggering. A constant-volume optical chamber was designed to facilitate maximum optical access for the study of the jet macroscopic characteristics and jet-wall impingement at different injection pressures and injectors-wall distances. Measurement of the jet tip penetration and cone angle at different conditions are presented in this paper together with temporal presentation of the jet radial travel along the wall.

Current UK practices in the management of subacromial impingement.

Science.gov (United States)

Bryceland, James K; Drury, Colin; Tait, Gavin R

2015-07-01

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. BESS members were invited to complete a questionnaire and responses were received from 157 consultant shoulder surgeons. 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. 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.

Specific or general exercise strategy for subacromial impingement syndrome-does it matter?

DEFF Research Database (Denmark)

Shire, Alison R; Stæhr, Thor A B; Overby, Jesper B

2017-01-01

Background Exercise is frequently suggested as a treatment option for patients presenting with symptoms of subacromial impingement syndrome. Some would argue implementing a specific exercise strategy with special focus on correction of kinematic deficits would be superior to general exercise stra...

Combined Anterolateral, Anterior, and Anteromedial Ankle Impingement in an Adolescent Soccer Player-A Case Report and Review of the Literature.

Science.gov (United States)

Cosma, Dan I; Vasilescu, Dana E; Corbu, Andrei; Todor, Adrian; Valeanu, Madalina; Ulici, Alexandru

2018-01-24

A unique case of combined anterolateral, anterior, and anteromedial ankle impingement in an adolescent soccer player is presented in this article. To the best of our knowledge, this is the only report of circumferential, massive, anterior ankle impingement in children described in the literature. The importance of proper diagnosis and treatment of such a lesion is illustrated in this case report. We also emphasize that clinical examination combined with 3D computed tomography scan reconstruction is an excellent and cost-effective imaging modality that can help with the diagnosis of anterior ankle impingement. Finally, open surgical treatment showed excellent results in an elite athlete.

[Efficacies of arthroscopic debridement and olecranon fossa plasty in the treatment of osteoarthritis and posterior elbow impingement].

Science.gov (United States)

Liu, Yu-jie; Wang, Jun-liang; Li, Hai-feng; Qi, Wei; Wang, Ning

2012-07-17

To evaluate the efficacies of arthroscopic debridement and removal of osteophyma for olecroanon and olecranon fossa plasty for posterior impingement of elbow joint. Between 1999 and 2008, a total of 21 cases were diagnosed with osteoarthritis and posterior elbow impingement. There were 15 males and 6 females. And there were 16 right and 15 left cases. They included volleyball players (n = 7), tennis players (n = 7), golf enthusiasts (n = 4) and fencers (n = 3). The average duration of onset-operation was 3.5 years (range: 2.5 - 8). Arthroscopic exploration revealed synovial hyperplasia hypertrophy, cartilage degeneration and olecranon fossa hyperplasia with deformed olecranon fossa. Debridement and plasty were performed. Loose bodies were removed from elbow joint in 6 patients. Partial resection of posterior olecranon tip was performed and osteophytes or fibrous tissue removed in this area. Dynamic observation showed no posterior elbow impingement. Postoperative follow-up was conducted in 19 cases and 2 cases became lost to follow-up. The average follow-up period was 25.3 months (range: 18 - 42). All patients were evaluated preoperatively and postoperatively with the Hospital for Special Surgery Elbow Assessment Scale. The outcomes were excellent (n = 12), good (n = 7) and fair (n = 2). Postoperative patients elbow swelling and pain relieve, sports and life function returns to normal, elbow flexion and rotating mobility obviously improved. With the elbow radiological films to measure the range of motion, the average range of motion was 90.5° preoperatively and improved to 130° postoperatively. There was significant improvement in all cases. Posterior elbow impingement is caused by hyperextension trauma and elbow overuse during specific sporting activities. Arthroscopic debridement and olecroanon or olecranon fossa plasty demonstrates excellent results for posterior impingement of elbow joint.

Experimentally induced cam impingement in the sheep hip.

Science.gov (United States)

Siebenrock, Klaus A; Fiechter, Ruth; Tannast, Moritz; Mamisch, Tallal C; von Rechenberg, Brigitte

2013-04-01

Sheep hips have a natural non-spherical femoral head similar to a cam-type deformity in human beings. By performing an intertrochanteric varus osteotomy, cam-type femoro-acetabular impingement (FAI) during flexion can be created. We tested the hypotheses that macroscopic lesions of the articular cartilage and an increased Mankin score (MS) can be reproduced by an experimentally induced cam-type FAI in this ovine in vivo model. Furthermore, we hypothesized that the MS increases with longer ambulatory periods. Sixteen sheep underwent unilateral intertrochanteric varus osteotomy of the hip with the non-operated hip as a control. Four sheep were sacrificed after 14, 22, 30, and 38-weeks postoperatively. We evaluated macroscopic chondrolabral alterations, and recorded the MS, based on histochemical staining, for each ambulatory period. A significantly higher prevalence of macroscopic chondrolabral lesions was found in the impingement zone of the operated hips. The MS was significantly higher in the acetabular/femoral cartilage of the operated hips. Furthermore, these scores increased as the length of the ambulatory period increased. Cam-type FAI can be induced in an ovine in vivo model. Localized chondrolabral degeneration of the hip, similar to that seen in humans (Tannast et al., Clin Orthop Relat Res 2008; 466: 273-280; Beck et al., J Bone Joint Surg Br 2005; 87: 1012-1018), can be reproduced. This experimental sheep model can be used to study cam-type FAI. Copyright © 2012 Orthopaedic Research Society.

Tongue metastasis mimicking an abscess.

Science.gov (United States)

Mavili, Ertuğrul; Oztürk, Mustafa; Yücel, Tuba; Yüce, Imdat; Cağli, Sedat

2010-03-01

Primary tumors metastasizing to the oral cavity are extremely rare. Lung is one of the most common primary sources of metastases to the tongue. Although the incidence of lung cancer is increasing, tongue metastasis as the initial presentation of the tumor remains uncommon. Due to the rarity of tongue metastasis, little is known about its imaging findings. Herein we report the magnetic resonance imaging and clinical findings of a lingual metastasis, mimicking an abscess, from a primary lung cancer.

Iliacus Abscess with Radiculopathy Mimicking Herniated Nucleus ...

African Journals Online (AJOL)

2016-05-02

May 2, 2016 ... radiculopathy mimicking herniated nucleus pulposus: Aadditional diagnostic value of magnetic resonance imaging. Niger J Clin Pract. 2017;20:392-3. This is an open access article distributed under the terms of the Creative Commons. Attribution-Non Commercial-Share Alike 3.0 License, which allows ...

Subscapulais injuries associated with acromiohumeral instability in patients with shoulder impingement syndrome

Energy Technology Data Exchange (ETDEWEB)

Moon, Tae Young; Jeong, Hee Seok; Lee, Seung Jun; Jeong, Yeo Jin [Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of)

2017-07-15

To evaluate the association of subscapularis (SSC) injuries with acromiohumeral instability (AHI) in patients with shoulder impingement syndrome with supraspinatus (SSP) tears. Pre-operative shoulder magnetic resonance images of 106 patients with subsequent arthroscopic confirmation of shoulder impingement syndrome were reviewed retrospectively. Patients with SSC injuries were divided into the following 3 groups: 1) those with no injury symbolized to the SSC[0] (n = 38), 2) those with partial injuries to the SSC[1] (n = 41), and 3) those with complete disruption of the SSC[2] (n = 27). AHI was categorized into 5 stages depending on the SSP lesions: partial tear or pretear tendinosis symbolized to the SSP[0] (n = 24) and according to retraction severity of the SSP tendon with complete tear such as SSP[1] (n = 19), SSP[2] (n = 27), SSP[3] (n = 29), and SSP[4] (n = 7). Also, AHI was divided into two groups such as the mild group summed with SSP plus SSP plus SSP and the severe group summed with SSP plus SSP, including 70 patients and 36 patients, respectively. Twenty-nine patients (63.0%) among 46 patients with SSC[0] and thirty-two patients (78.0%) among 41 patients with SSC[1] were related to mild AHI. Eighteen patients (66.7%) among 27 patients with SSC[2] were associated with severe AHI. The SSC injury groups were statistically significantly associated with AHI (estimate 0.207, standard error 0.057, p < 0.01). SSC injuries could be related to AHI in patients with shoulder impingement syndrome.

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.

Clozapine Intoxication Mimicking Acute Stroke

Directory of Open Access Journals (Sweden)

Joshua D. Villarreal

2018-04-01

Full Text Available Clozapine is an atypical antipsychotic drug prescribed for treatment-resistant schizophrenia. The risk of adverse hematologic, cardiovascular, and neurologic effects has tempered its use, and reports of overdoses remain rare. We report a case of accidental acute clozapine intoxication in a clozapine-naïve patient, who presented with symptoms mimicking acute stroke and later developed status epilepticus. Clozapine intoxication is a rare presentation in the emergency department with potential for iatrogenic harm if not correctly identified.

Scapular Notching on Kinematic Simulated Range of Motion After Reverse Shoulder Arthroplasty Is Not the Result of Impingement in Adduction

Science.gov (United States)

Lädermann, Alexandre; Gueorguiev, Boyko; Charbonnier, Caecilia; Stimec, Bojan V.; Fasel, Jean H.D.; Zderic, Ivan; Hagen, Jennifer; Walch, Gilles

2015-01-01

Abstract Impingement after reverse shoulder arthroplasty (RSA) is believed to occur from repetitive contact in adduction between the humeral component and the inferior scapular pillar. The primary purpose of this biomechanical study was to confirm the presence of different types of impingement and to examine which daily-life movements are responsible for them. A secondary aim was to provide recommendations on the type of components that would best minimize notching and loss of range of motion (ROM). The study included 12 fresh frozen shoulder specimens; each had a computed tomography (CT) image of the entire scapula and humerus in order to acquire topological information of the bones before RSA implantation. Cyclic tests were run postimplantation with 3 shoulders in each modalities. To quantify bone loss due to impingement, 3-dimensional anatomical models of the scapula were reconstructed from the CT scans and compared to their intact states. We found 8 bony impingements in 7 specimens: 2 at the lateral acromion, 1 at the inferior acromion, 4 scapular notching, and 1 with the glenoid resulting to wear at the 3:00 to 6:00 clock-face position. Impingements occurred in all kinds of tested motions, except for the internal/external rotation at 90° of abduction. The 3 specimens tested in abduction/adduction presented bone loss on the acromion side only. Scapular notching was noted in flexion/extension and in internal/external rotation at 0° of abduction. The humeral polyethylene liner was worn in 2 specimens—1 at the 6:00 to 8:00 clock-face position during internal/external rotation at 0° of abduction and 1 at the 4:00 clock-face position during flexion/extension. The present study revealed that 2 types of impingement interactions coexist and correspond to a frank abutment or lead to a scapular notching (friction-type impingement). Scapular notching seems to be caused by more movements or combination of movements than previously considered, and in particular by

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

Deep Granuloma Annulare Mimicking Inflamed Cysts in a Teenager.

Science.gov (United States)

Guo, Emily L; Degesys, Catherine A; Jahan-Tigh, Richard; Chan, Audrey

2017-07-01

We describe deep granuloma annulare (DGA) of the forehead mimicking inflamed cysts. Reactive inflammation and sterile purulent drainage may be an underrecognized feature of DGA. © 2017 Wiley Periodicals, Inc.

Cam-type femoral-acetabular impingement: is the alpha angle the best MR arthrography has to offer?

International Nuclear Information System (INIS)

Lohan, Derek G.; Seeger, Leanne L.; Motamedi, Kambiz; Sayre, James; Hame, Sharon

2009-01-01

In our institutional experience, determination of the alpha (α) angle at MR arthrography as an indicator of the likelihood of cam-type femoroacetabular impingement (FAI) is fraught with inconsistency. The aims of this study were to quantify the degree of variability in and calculate the diagnostic accuracy of the α angle in suggesting a diagnosis of cam impingement, to determine the accuracy of a positive clinical impingement test, and to suggest alternative MR arthrographic measures of femoral head-neck overgrowth and determine their diagnostic utilities. We carried out a retrospective analysis of MR arthrographic studies performed during a 4-year period, combined with chart analysis, which allowed identification of 78 patients in whom surgical correlation was also available. The status of a preoperative clinical impingement test was also noted. Patients were designated as having cam-type FAI (Group A, n = 39) if intra-operative femoral head-neck junction bony osteochondroplasty/arthoscopic femoral debridement was performed. Group B (n = 39) acted as controls. Three radiologists independently and blindly performed a series of measurements (α angle and two newly proposed measurements) in each patient on two separate occasions. An α angle of greater than 55 was considered indicative of the presence of cam-type FAI. Performance values for α angle measurement were poor for each observer. There was considerable (up to 30% of the mean value) intra-observer variability between the first and second α angle measurements for each subject. Binary logistic regression analysis confirmed that the α angle is of no value in predicting the presence or absence of cam-FAI. A statistically significant difference existed between Groups A and B with regard to the newly proposed anterior femoral distance (AFD; p = 0.004). Using an AFD value of 3.60 mm or greater as being indicative of the presence of cam-FAI yields a 0.67 performance measure (95% confidence interval 0

Numerical study of unsteady MHD oblique stagnation point flow and heat transfer due to an oscillating stream

Science.gov (United States)

Javed, T.; Ghaffari, A.; Ahmad, H.

2016-05-01

The unsteady stagnation point flow impinging obliquely on a flat plate in presence of a uniform applied magnetic field due to an oscillating stream has been studied. The governing partial differential equations are transformed into dimensionless form and the stream function is expressed in terms of Hiemenz and tangential components. The dimensionless partial differential equations are solved numerically by using well-known implicit finite difference scheme named as Keller-box method. The obtained results are compared with those available in the literature. It is observed that the results are in excellent agreement with the previous studies. The effects of pertinent parameters involved in the problem namely magnetic parameter, Prandtl number and impinging angle on flow and heat transfer characteristics are illustrated through graphs. It is observed that the influence of magnetic field strength increases the fluid velocity and by the increase of obliqueness parameter, the skin friction increases.

Heat/mass transfer on effusion plate with circular pin fins for impingement/effusion cooling system with initial crossflow

International Nuclear Information System (INIS)

Hong, Sung Kook; Rhee, Dong Ho; Cho, Hyung Hee

2005-01-01

Impingement/effusion cooling technique is used for combustor liner or turbine parts cooling in gas turbine engine. In the impingement/effusion cooling system, the crossflow generated in the cooling channel induces an adverse effect on the cooling performance, which consequently affects the durability of the cooling system. In the present study, to reduce the adverse effect of the crossflow and improve the cooling performance, circular pin fins are installed in impingement/effusion cooling system and the heat transfer characteristics are investigated. The pin fins are installed between two perforated plates and the crossflow passes between these two plates. A blowing ratio is changed from 0.5 to 1.5 for the fixed jet Reynolds number of 10,000 and five circular pin fin arrangements are considered in this study. The local heat/mass transfer coefficients on the effusion plate are measured using a naphthalene sublimation method. The results show that local distributions of heat/mass transfer coefficient are changed due to the installation of pin fins. Due to the generation of vortex and wake by the pin fin, locally low heat/mass transfer regions are reduced. Moreover, the pin fin prevents the wall jet from being swept away, resulting in the increase of heat/mass transfer. When the pin fin is installed in front of the impinging jet, the blockage effect on the crossflow enhances the heat/mass transfer. However, the pin fin installed just behind the impinging jet blocks up the wall jet, decreasing the heat/mass transfer. As the blowing ratio increases, the pin fins lead to the higher Sh value compared to the case without pin fins, inducing 16%∼22% enhancement of overall Sh value at high blowing ratio of M=1.5

The sagittal stem alignment and the stem version clearly influence the impingement-free range of motion in total hip arthroplasty: a computer model-based analysis.

Science.gov (United States)

Müller, Michael; Duda, Georg; Perka, Carsten; Tohtz, Stephan

2016-03-01

The component alignment in total hip arthroplasty influences the impingement-free range of motion (ROM). While substantiated data is available for the cup positioning, little is known about the stem alignment. Especially stem rotation and the sagittal alignment influence the position of the cone in relation to the edge of the socket and thus the impingement-free functioning. Hence, the question arises as to what influence do these parameters have on the impingement-free ROM? With the help of a computer model the influence of the sagittal stem alignment and rotation on the impingement-free ROM were investigated. The computer model was based on the CT dataset of a patient with a non-cemented THA. In the model the stem version was set at 10°/0°/-10° and the sagittal alignment at 5°/0°/-5°, which resulted in nine alternative stem positions. For each position, the maximum impingement-free ROM was investigated. Both stem version and sagittal stem alignment have a relevant influence on the impingement-free ROM. In particular, flexion and extension as well as internal and external rotation capability present evident differences. In the position intervals of 10° sagittal stem alignment and 20° stem version a difference was found of about 80° in the flexion and 50° in the extension capability. Likewise, differences were evidenced of up to 72° in the internal and up to 36° in the external rotation. The sagittal stem alignment and the stem torsion have a relevant influence on the impingement-free ROM. To clarify the causes of an impingement or accompanying problems, both parameters should be examined and, if possible, a combined assessment of these factors should be made.

Advanced Imaging in Femoroacetabular Impingement: Current State and Future Prospects

OpenAIRE

Bittersohl, Bernd; Hosalkar, Harish S.; Hesper, Tobias; Tiderius, Carl Johan; Zilkens, Christoph; Krauspe, R?diger

2015-01-01

Symptomatic femoroacetabular impingement (FAI) is now a known precursor of early osteoarthritis (OA) of the hip. In terms of clinical intervention, the decision between joint preservation and joint replacement hinges on the severity of articular cartilage degeneration. The exact threshold during the course of disease progression when the cartilage damage is irreparable remains elusive. The intention behind radiographic imaging is to accurately identify the morphology of osseous structural abn...

Scapula kinematics of pull-up techniques: Avoiding impingement risk with training changes.

Science.gov (United States)

Prinold, Joe A I; Bull, Anthony M J

2016-08-01

Overhead athletic activities and scapula dyskinesia are linked with shoulder pathology; pull-ups are a common training method for some overhead sports. Different pull-up techniques exist: anecdotally some are easier to perform, and others linked to greater incidences of pathology. This study aims to quantify scapular kinematics and external forces for three pull-up techniques, thus discussing potential injury implications. An observational study was performed with eleven participants (age=26.8±2.4 years) who regularly perform pull-ups. The upward motions of three pull-up techniques were analysed: palms facing anterior, palms facing posterior and wide-grip. A skin-fixed scapula tracking technique with attached retro-reflective markers was used. High intra-participant repeatability was observed: mean coefficients of multiple correlations of 0.87-1.00 in humerothoracic rotations and 0.77-0.90 for scapulothoracic rotations. Standard deviations of hand force was low: kinematics were observed between the pull-up techniques. The reverse technique has extreme glenohumeral internal-external rotation and large deviation from the scapula plane. The wide technique has a reduced range of pro/retraction in the same HT plane of elevation and 90° of arm abduction with 45° external rotation was observed. All these factors suggest increased sub-acromial impingement risk. The scapula tracking technique showed high repeatability. High arm elevation during pull-ups reduces sub-acromial space and increases pressure, increasing the risk of impingement injury. Wide and reverse pull-ups demonstrate kinematics patterns linked with increased impingement risk. Weight-assisted front pull-ups require further investigation and could be recommended for weaker participants. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Experimental investigation on heat transfer of HEMJ type divertor with narrow gap between nozzle and impingement surface

International Nuclear Information System (INIS)

Yokomine, Takehiko; Oohara, Ken; Kunugi, Tomoaki

2016-01-01

Highlights: • We performed heat transfer experiment on HEMJ-type multiple jet impingement. • For narrow gap case, degradation of heat transfer performance was observed. • The re-laminarization was anticipated if the temperature level is high. • For actual design of divertor cooling, the re-laminarization must be considered. - Abstract: In order to explore the possibility of improvement of the He-cooled modular divertor with multiple jet cooling (HEMJ) concept including optimization of design parameter, an experimental study on heat transfer performance of the HEMJ divertor was performed by means of helium loop at Georgia Tech, in which the pressure, flow rate and temperature of helium pressure is up to 10 MPa, 8 g/s and 300 °C, respectively, under heat flux of 6 MW/m"2 loaded by means of induction heater. Although the non-dimensional distance between jet nozzle and impingement surface H normalized by typical nozzle diameter D, H/D is 0.9 in the reference design of HEMJ, heat transfer experiments were carried out under the condition of H/D = 0.5 and 0.25 to enhance the heat transfer performance. In the case of H/D = 0.25, the averaged Nusselt number was increased by about 20% from the value for H/D = 0.5 in the case that the jet temperature less than 100 °C. By contraries, the averaged Nusselt number was decreased with increase in jet temperature which is larger than 200 °C in the H/D = 0.25 case. It is expected that the degradation of heat transfer performance with increasing the jet temperature is caused by the re-laminarization occurred near heat transfer surface.

THE DEVELOPMENT OF IODINE BASED IMPINGER SOLUTIONS FOR THE EFFICIENT CAPTURE OF HG USING DIRECT INJECTION NEBULIZATION - INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY ANALYSIS

Science.gov (United States)

Inductively coupled plasma mass spectrometry (ICP/MS) with direct injection nebulization (DIN) was used to evaluate novel impinger solution compositions capable of capturing elemental mercury (Hgo) in EPA Method 5 type sampling. An iodine based impinger solutoin proved to be ver...

Quantitative Measurements using Ultrasound Vector Flow Imaging

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt

2016-01-01

scanner for pulsating flow mimicking the femoral artery from a CompuFlow 1000 pump (Shelley Medical). Data were used in four estimators based on directional transverse oscillation for velocity, flow angle, volume flow, and turbulence estimation and their respective precisions. An adaptive lag scheme gave...... the ability to estimate a large velocity range, or alternatively measure at two sites to find e.g. stenosis degree in a vessel. The mean angle at the vessel center was estimated to 90.9◦±8.2◦ indicating a laminar flow from a turbulence index being close to zero (0.1 ±0.1). Volume flow was 1.29 ±0.26 mL/stroke...... (true: 1.15 mL/stroke, bias: 12.2%). Measurements down to 160 mm were obtained with a relative standard deviation and bias of less than 10% for the lateral component for stationary, parabolic flow. The method can, thus, find quantitative velocities, angles, and volume flows at sites currently...

Flow simulation of a Pelton bucket using finite volume particle method

International Nuclear Information System (INIS)

Vessaz, C; Jahanbakhsh, E; Avellan, F

2014-01-01

The objective of the present paper is to perform an accurate numerical simulation of the high-speed water jet impinging on a Pelton bucket. To reach this goal, the Finite Volume Particle Method (FVPM) is used to discretize the governing equations. FVPM is an arbitrary Lagrangian-Eulerian method, which combines attractive features of Smoothed Particle Hydrodynamics and conventional mesh-based Finite Volume Method. This method is able to satisfy free surface and no-slip wall boundary conditions precisely. The fluid flow is assumed weakly compressible and the wall boundary is represented by one layer of particles located on the bucket surface. In the present study, the simulations of the flow in a stationary bucket are investigated for three different impinging angles: 72°, 90° and 108°. The particles resolution is first validated by a convergence study. Then, the FVPM results are validated with available experimental data and conventional grid-based Volume Of Fluid simulations. It is shown that the wall pressure field is in good agreement with the experimental and numerical data. Finally, the torque evolution and water sheet location are presented for a simulation of five rotating Pelton buckets

Erosion of a grooved surface caused by impact of particle-laden flow

Science.gov (United States)

Jung, Sohyun; Yang, Eunjin; Kim, Ho-Young

2016-11-01

Solid erosion can be a life-limiting process for mechanical elements in erosive environments, thus it is of practical importance in many industries such as construction, mining, and coal conversion. Erosion caused by particle-laden flow occurs through diverse mechanisms, such as cutting, plastic deformation, brittle fracture, fatigue and melting, depending on particle velocity, total particle mass and impingement angle. Among a variety of attempts to lessen erosion, here we investigate the effectiveness of millimeter-sized grooves on the surface. By experimentally measuring the erosion rates of smooth and triangular-grooved surfaces under various impingement angles, we find that erosion can be significantly reduced within a finite range of impingement angles. We show that such erosion resistance is attributed to the swirls of air within grooves and the differences in erosive strength of normal and slanted impact. In particular, erosion is mitigated when we increase the effective area under normal impact causing plastic deformation and fracture while decreasing the area under slanted impact that cuts the surface to a large degree. Our quantitative model for the erosion rate of grooved surfaces considering the foregoing effects agrees with the measurement results.

Survival of fishes after impingement on traveling screens at Hudson River power plants

International Nuclear Information System (INIS)

Muessig, P.H.; Hutchison, J.B.; King, L.R.; Ligotino, R.J.; Daley, M.

1988-01-01

The survival of Hudson River fishes, juveniles and adults, after they had been impinged on continuously rotated traveling screens at the Bowline Point and Danskammer Point power plants was examined. Survival of principal species was similar at the two plants, and estimates of survival improved as monitoring stress was reduced. Adjusted for survival of control fish, survival over 84-108 h after fish were recovered from the screens was highest for Atlantic tomcod, striped bass, and white perch (50-90%) and lowest for bay anchovy, alewife, and blueback herring; other species showed intermediate survival. Survival of striped bass and white perch was positively correlated with water temperature in winter and with conductivity in spring and fall. Continual rotation of the screens, which shortens the average time that fish are impinged, increased survival over that associated with intermittent rotation. 24 refs., 9 figs., 4 tabs

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...

Orthokeratinised odontogenic cyst mimicking periapical cyst

OpenAIRE

Rajalakshmi, R; Sreeja, C; Vijayalakshmi, D; Leelarani, V

2013-01-01

Orthokeratinised odontogenic cyst (OOC) denotes the odontogenic cyst that microscopically has an orthokeratinised epithelial lining. OOC is characterised by a less-aggressive behaviour and a low rate of recurrence. This report describes a case of OOC involving posterior part of the mandible that mimicked periapical cyst in a 14-year-old boy. The initial clinical diagnosis was given as periapical cyst based on the clinical and radiographical features. Enucleation of the cyst was performed and ...

Calibrating Doppler imaging of preterm intracerebral circulation using a microvessel flow phantom

Directory of Open Access Journals (Sweden)

Fleur A. Camfferman

2015-01-01

Full Text Available Introduction. Preterm infants are born during critical stages of brain development, in which the adaptive capacity of the fetus to extra-uterine environment is limited. Inadequate brain perfusion has been directly linked to preterm brain damage. Advanced high-frequency ultrasound probes and processing algorithms allow visualization of microvessels and depiction of regional variation. To assess whether visualization and flow velocity estimates of preterm cerebral perfusion using Doppler techniques is accurate, we conducted an in vitro experiment using a microvessel flow phantom.Materials and Methods. An in-house developed flow phantom containing two microvessels (inner diameter 200 and 700 microns with attached syringe pumps, filled with blood-mimicking fluid, was used to generate non-pulsatile perfusion of variable flow. Measurements were performed using an Esaote MyLab70 scanner.Results. Microvessel mimicking catheters with velocities as low as 1cm/sec were adequately visualized with a linear ultrasound probe. With a convex probe velocities <2 cm/sec could not be depicted. Within settings, velocity and diameter measurements were highly reproducible (intra class correlation 0.997 (95% CI 0.996-0.998 and 0.914 (0.864-0.946. Overall, mean velocity was overestimated up to 3-fold, especially in high velocity ranges. Significant differences were seen in velocity measurements when using steer angle correction and in vessel diameter estimation (p<0.05.Conclusion. Visualization of microvessel size catheters mimicking small brain vessels is feasible. Reproducible velocity and diameter results can be obtained, although important overestimation of the values is observed. Before velocity estimates of microcirculation can find its use in clinical practice, calibration of the ultrasound machine for any specific Doppler purpose is essential. The ultimate goal is to develop a sonographic tool that can be used for objective study of regional perfusion in routine

Numerical simulation of flow characteristics of lean jet to cross-flow in safety injection of reactor cooling system

International Nuclear Information System (INIS)

Wang Haijun; He Huining; Luo Yushan; Wang Weishu

2011-01-01

In the present work, a numerical simulation was performed to study the flow characteristics of lean jet to cross flow in a main tube in the safety injection of reactor cooling system. The influence scope and mixing characteristics of the confined lean jet in cross-flow were studied. It can be concluded that three basic flow regimes are marked, namely the attached lean jet, lift-off lean jet and impinging lean jet. The velocity ratio V R is the key factor in the flow state. The depth and region of jet to main flow are enhanced with the increase of the velocity ratio. The jet flow penetrates through the main flow with the increase of the velocity ratio. At higher velocity ratio, the jet flow strikes the main flow bottom and circumfluence happens in upriver of main flow. The vortex flow characteristics dominate the flow near region of jet to cross-flow and the mixture of jet to cross-flow. At different velocity ratio V R , the vortex grows from the same displacement, but the vortex type and the vortex is different. At higher velocity ratio, the vortex develops fleetly, wears off sharp and dies out sharp. The study is very important to the heat transfer experiments of cross-flow jet and thermal stress analysis in the designs of nuclear engineering. (authors)

Ectopic decidual reaction mimicking inguinal lymphoma on ultrasound

DEFF Research Database (Denmark)

Lorentzen, C.; Prangsgaard, Tina; Lorentzen, Torben

2014-01-01

Ectopic decidual reaction has been described in various intraperitoneal locations. We present a case of unusual ectopic decidual reaction in the groin mimicking inguinal lymphoma on ultrasound in a pregnant woman. This case contributes evidence illustrating the variability of the clinical...... presentation of ectopic decidual reaction....

Rare extraskeletal Ewing's sarcoma mimicking as adenocarcinoma of the sigmoid.

Science.gov (United States)

Mertens, Michelle; Haenen, Filip W N; Siozopoulou, Vasiliki; Van Cleemput, Marc

2017-06-01

Extraskeletal Ewing's sarcoma (EES) is a rare finding in comparison with Ewing's sarcoma of bone and usually manifests in young patients. However, even in older patients, one must consider the diagnosis. In this case, we describe a 52-year-old woman diagnosed with EES, mimicking as adenocarcinoma of the sigmoid. The tumor was not visualized by a multi-slice spiral computed tomography of the abdomen and pelvis with intravenous contrast, and eventually the diagnosis was made by positive immunohistochemical staining for CD99 and by molecular testing for EWSR1 translocation. This combination of the patient's age and the localization of the tumor mimicking an adenocarcinoma of the sigmoid has never been described before.

Evaluation of a barrier net used to mitigate fish impingement at a Hudson River power plant intake

International Nuclear Information System (INIS)

Hutchison, J.B.; Matousek, J.A.

1988-01-01

A multifilament nylon net of 0.95-cm bar mesh was deployed as a physical barrier to fish in front of the Bowline Point power plant cooling water intake on the Hudson River from 1976 to 1985. The barrier net was deployed during the historical peak impingement months of October-May. The primary species impinged on the intake screens during this period were young-of-year and yearling white perch, striped bass, rainbow smelt, alewife, blue-back herring, and American shad, generally ranging from 5 to 10 cm in total length. When the barrier net was deployed, median impingement of all fish was 91% lower than during comparable periods before the net was installed. A mark-recapture population estimate indicated that 230,000 yearling striped bass and white perch were in the embayment outside the net in April 1982; over a 9-d study period, only 1.6% of this estimated population was impinged. Concurrent survival probability studies of fish marked and released at locations inside and outside the barrier net showed that fish released inside had 72% lower survival (P

Effect of trailing edge ramp on cavity flow structures and pressure drag

International Nuclear Information System (INIS)

Pey, Yin Yin; Chua, Leok Poh; Siauw, Wei Long

2014-01-01

Highlights: • Trailing edge ramps were used to reduce unsteadiness and pressure drag of a cavity. • Proper Orthogonal Decomposition was used to educe the coherent structures. • The 30° ramp was successful in redistributing the energy content within the cavity. • The 30° ramp guides the flow smoothly out of the cavity, reducing flow impingement. • A substantial reduction of pressure drag was achieved by the 30° ramp. -- Abstract: The effects of trailing edge ramp modifications on time-averaged velocity and pressure distributions within a cavity with a length to depth ratio of 2, at a speed of 15 m/s were investigated. The ramp angles were varied at 30°, 45° and 60° and ramp heights were varied at 0.25 times and 0.5 times of cavity depth. The mean flow within the cavity differed significantly from the baseline case when ramp angle was 30° and 45° with ramp height 0.5 times of cavity depth. At these 2 configurations, moment about the center of the cavity floor was reduced significantly. These could be attributed to the more steady flow within the cavity as compared to the baseline case. Spatial correlation of velocity in the cavity of ramp angle 30° showed that internal cavity flow was less sensitive to flow changes in the shear layer as compared to the baseline case. In the same cavity, snapshot Proper Orthogonal Decomposition revealed a redistribution of energy content where energetic structures exist only in the shear layer as opposed to energetic structures in both the shear layer and internal cavity for the baseline case. A reduction of pressure drag was also observed as the gentle ramp angle of 30° guides the flow smoothly out of the cavity and reduces trailing edge impingement

Tension pneumocephalus mimicking septic shock: a case report.

Science.gov (United States)

Miranda, Caroline; Mahta, Ali; Wheeler, Lee Adam; Tsiouris, A John; Kamel, Hooman

2018-02-01

Tension pneumocephalus can lead to rapid neurologic deterioration. We report for the first time its association with aseptic systemic inflammatory response syndrome mimicking septic shock and the efficacy of prompt neurosurgical intervention and critical care support in treating this condition. A 64-year-old man underwent 2-stage olfactory groove meningioma resection. The patient developed altered mental status and gait instability on postoperative day 6. Imaging showed significant pneumocephalus. The patient subsequently developed worsening mental status, respiratory failure, and profound shock requiring multiple vasopressors. Bedside needle decompression, identification and repair of the cranial fossa defect, and critical care support led to improved mental status and reversal of shock and multiorgan dysfunction. Thorough evaluation revealed no evidence of an underlying infection. In this case, tension pneumocephalus incited an aseptic systemic inflammatory response syndrome mimicking septic shock. Prompt neurosurgical correction of pneumocephalus and critical care support not only improved neurologic status, but also reversed shock. Such a complication indicates the importance of close monitoring of patients with progressive pneumocephalus.

Numerical analysis of high-speed Lithium jet flow under vacuum conditions

International Nuclear Information System (INIS)

Gordeev, Sergej; Groeschel, Friedrich; Stieglitz, Robert

2016-01-01

The EVEDA Li test loop (ELTL) [1] is aimed at validating the hydraulic stability of the Lithium (Li) target at a velocity up to 20 m/s at vacuum (≈10 −3 Pa). The ELTL has been designed to demonstrate the feasibility of the major components providing a neutron production liquid Li target for IFMIF. The rectangular shaped Li jet (cross-section 25 mm × 100 mm) necessitates for heat removal flow velocities of 15–20 m/s along a concave shaped back wall (curvature radius 250 mm) towards the outlet pipe, where the Li jet is subjected to vacuum before it finally enters the collecting quench tank. During the validation experiments within the ELTL acoustic waves within the target outlet pipe have been recorded, indicating potential cavitation processes in the jet impinging region, which may cause premature failures. In order to identify potential cavitation phenomena in correlation with the free jet flow in the outlet pipe a numerical study has been performed. The comparison measured and simulated acoustic emissions exhibits that experimentally deduced cavitation area coincides with the location of the jet wall impingement. The simulations further reveal that a part of the fluid after striking the wall even flows opposite to the gravity vector. This reversed flow is inherently unstable and characterized by waves at first growing and then bursting into droplets. The intense generation of small droplets increases significantly the Li free surface area and lead to a production of Li vapour, which is captured by the jet flow and reintroduced in the main flow. As the static pressure is recovered downstream due to jet impact, the vapour bubbles collapse and hence cavitation likely occurs.

Numerical analysis of high-speed Lithium jet flow under vacuum conditions

Energy Technology Data Exchange (ETDEWEB)

Gordeev, Sergej, E-mail: sergej.gordeev@kit.edu; Groeschel, Friedrich; Stieglitz, Robert

2016-11-01

The EVEDA Li test loop (ELTL) [1] is aimed at validating the hydraulic stability of the Lithium (Li) target at a velocity up to 20 m/s at vacuum (≈10{sup −3} Pa). The ELTL has been designed to demonstrate the feasibility of the major components providing a neutron production liquid Li target for IFMIF. The rectangular shaped Li jet (cross-section 25 mm × 100 mm) necessitates for heat removal flow velocities of 15–20 m/s along a concave shaped back wall (curvature radius 250 mm) towards the outlet pipe, where the Li jet is subjected to vacuum before it finally enters the collecting quench tank. During the validation experiments within the ELTL acoustic waves within the target outlet pipe have been recorded, indicating potential cavitation processes in the jet impinging region, which may cause premature failures. In order to identify potential cavitation phenomena in correlation with the free jet flow in the outlet pipe a numerical study has been performed. The comparison measured and simulated acoustic emissions exhibits that experimentally deduced cavitation area coincides with the location of the jet wall impingement. The simulations further reveal that a part of the fluid after striking the wall even flows opposite to the gravity vector. This reversed flow is inherently unstable and characterized by waves at first growing and then bursting into droplets. The intense generation of small droplets increases significantly the Li free surface area and lead to a production of Li vapour, which is captured by the jet flow and reintroduced in the main flow. As the static pressure is recovered downstream due to jet impact, the vapour bubbles collapse and hence cavitation likely occurs.

Electrocardiogram artifact caused by rigors mimicking narrow complex tachycardia: a case report.

Science.gov (United States)

Matthias, Anne Thushara; Indrakumar, Jegarajah

2014-02-04

The electrocardiogram (ECG) is useful in the diagnosis of cardiac and non-cardiac conditions. Rigors due to shivering can cause electrocardiogram artifacts mimicking various cardiac rhythm abnormalities. We describe an 80-year-old Sri Lankan man with an abnormal electrocardiogram mimicking narrow complex tachycardia during the immediate post-operative period. Electrocardiogram changes caused by muscle tremor during rigors could mimic a narrow complex tachycardia. Identification of muscle tremor as a cause of electrocardiogram artifact can avoid unnecessary pharmacological and non-pharmacological intervention to prevent arrhythmias.

Spatially-resolved, three-dimensional spray characterization of impinging jets by digital in-line holography

Science.gov (United States)

Gao, Jian; Rodrigues, Neil; Sojka, Paul; Chen, Jun

2014-11-01

The impinging jet injector is a preferred method for the atomization of liquid rocket propellants. The majority of experimental studies in literature are not spatially-resolved due to the limitations of widely available point-wise and two-dimensional (2D) diagnostic techniques such as phase Doppler anemometry (PDA), which requires significant experimental repetitions to give spatially-resolved measurements. In the present study, digital in-line holography (DIH) is used to provide spatially-resolved, three-dimensional (3D) characteristics of impinging jet sprays. A double-exposure DIH setup is configured to measure droplet 3D, three-component velocity as well as the size distribution. The particle information is extracted by the hybrid method, which is recently proposed as a particle detection method. To enlarge the detection volume, two parallel, collimated laser beams are used to simultaneously probe the spray at two locations, and two identical cameras are used to record the corresponding holograms. Such a setup has a detection volume of approximately 20 cm by 3.6 cm by 4.8 cm. Sprays of both Newtonian and non-Newtonian liquids corresponding to regimes at relatively lower jet Reynolds and Weber numbers are investigated. Measurements from DIH are further verified by comparison with experimental data obtained from shadowgraph and PDA. It is revealed that DIH is particularly suitable to provide spatially-resolved, 3D measurements of impinging jet sprays that are not particularly dense.

Diagnostic accuracy of clinical tests for the diagnosis of hip femoroacetabular impingement/labral tear

DEFF Research Database (Denmark)

Reiman, M P; Goode, A P; Cook, C E

2015-01-01

BACKGROUND: Surgery for hip femoroacetabular impingement/acetabular labral tear (FAI/ALT) is exponentially increasing despite lacking investigation of the accuracy of various diagnostic measures. Useful clinical utility of these measures is necessary to support diagnostic imaging and subsequent...

Intra-abdominal gout mimicking pelvic abscess

International Nuclear Information System (INIS)

Chen, Chia-Hui; Chen, Clement Kuen-Huang; Yeh, Lee-Ren; Pan, Huay-Ban; Yang, Chien-Fang

2005-01-01

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.)

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.)

Nucleus-staining with biomolecule-mimicking nitrogen-doped carbon dots prepared by a fast neutralization heat strategy.

Science.gov (United States)

Kang, Yan-Fei; Fang, Yang-Wu; Li, Yu-Hao; Li, Wen; Yin, Xue-Bo

2015-12-11

Biomolecule-mimicking nitrogen-doped carbon dots (N-Cdots) were synthesized from dopamine by a neutralization heat strategy. Fluorescence imaging of various cells validated their nucleus-staining efficiency. The dopamine-mimicking N-Cdots "trick" nuclear membranes to achieve nuclear localization and imaging.

Hip arthroscopy for femoroacetabular impingement

Science.gov (United States)

Nasser, Rima; Domb, Benjamin

2018-01-01

The purpose of this article is to give a general overview of femoroacetabular impingement (FAI) and how it could be treated arthroscopically, with some details about indications, the procedure itself and some of the complications associated with the surgery. FAI is a dynamic condition of the hip that can be a source of pain and disability and could potentially lead to arthritis. When symptomatic, and if conservative treatment fails, FAI can be addressed surgically. The goal of surgical treatment for FAI is to recreate the spherical contour of the femoral head, improve femoral offset, normalize coverage of the acetabulum, repair/reconstruct chondral damage and repair/reconstruct the labrum to restore normal mechanics and joint sealing. Advances in equipment and technique have contributed to an increase in the number of hip arthroscopy procedures performed worldwide and have made it one of the more common treatment options for symptomatic FAI. Hip arthroscopy is a procedure with an extremely steep and long learning curve. Cite this article: EFORT Open Rev 2018;3:121-129. DOI: 10.1302/2058-5241.3.170041 PMID:29780619

Imaging findings of mimickers of hepatocellular carcinoma

Directory of Open Access Journals (Sweden)

Tae Kyoung Kim

2015-12-01

Full Text Available Radiological imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC as the noninvasive diagnosis of HCC in high-risk patients by typical imaging findings alone is widely adopted in major practice guidelines for HCC. While imaging techniques have markedly improved in detecting small liver lesions, they often detect incidental benign liver lesions and non-hepatocellular malignancy that can be misdiagnosed as HCC. The most common mimicker of HCC in cirrhotic liver is nontumorous arterioportal shunts that are seen as focal hypervascular liver lesions on dynamic contrast-enhanced cross-sectional imaging. Rapidly enhancing hemangiomas can be easily misdiagnosed as HCC especially on MR imaging with liver-specific contrast agent. Focal inflammatory liver lesions mimic HCC by demonstrating arterial-phase hypervascularity and subsequent washout on dynamic contrast-enhanced imaging. It is important to recognize the suggestive imaging findings for intrahepatic cholangiocarcinoma (CC as the management of CC is largely different from that of HCC. There are other benign mimickers of HCC such as angiomyolipomas and focal nodular hyperplasia-like nodules. Recognition of their typical imaging findings can reduce false-positive HCC diagnosis.

Is there any value to arthroscopic debridement of ankle osteoarthritis and impingement?

Science.gov (United States)

Phisitkul, Phinit; Tennant, Joshua N; Amendola, Annunziato

2013-09-01

This article summarizes the current literature regarding the use of arthroscopy for the various types of ankle osteoarthritis with impingement symptoms. Discussion includes the role of diagnostic arthroscopy and adjunctive use of arthroscopy with other modalities. The section on the authors' preferred technique describes our current operative and perioperative strategies in detail. Published by Elsevier Inc.

Osteoid osteoma and osteoid osteoma-mimicking lesions: biopsy findings, distinctive MDCT features and treatment by radiofrequency ablation

Energy Technology Data Exchange (ETDEWEB)

Becce, Fabio [Centre Hospitalier Universitaire Vaudois, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland); Universite Paris Descartes, Department of Radiology B, Hopital Cochin, AP-HP, Paris (France); Theumann, Nicolas [Centre Hospitalier Universitaire Vaudois, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland); Rochette, Antoine; Campagna, Raphael; Drape, Jean-Luc; Feydy, Antoine [Universite Paris Descartes, Department of Radiology B, Hopital Cochin, AP-HP, Paris (France); Larousserie, Frederique [Universite Paris Descartes, Department of Anatomic Pathology, Hopital Cochin, AP-HP, Paris (France); Cherix, Stephane; Mouhsine, Elyazid [Centre Hospitalier Universitaire Vaudois, Department of Orthopaedic and Traumatologic Surgery, Lausanne (Switzerland); Guillou, Louis [University Institute of Pathology, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Anract, Philippe [Universite Paris Descartes, Department of Orthopaedic Surgery, Hopital Cochin, AP-HP, Paris (France)

2010-10-15

To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA). In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated. Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%. Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA. (orig.)

Osteoid osteoma and osteoid osteoma-mimicking lesions: biopsy findings, distinctive MDCT features and treatment by radiofrequency ablation

International Nuclear Information System (INIS)

Becce, Fabio; Theumann, Nicolas; Rochette, Antoine; Campagna, Raphael; Drape, Jean-Luc; Feydy, Antoine; Larousserie, Frederique; Cherix, Stephane; Mouhsine, Elyazid; Guillou, Louis; Anract, Philippe

2010-01-01

To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA). In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated. Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%. Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA. (orig.)

Peroxidase-Mimicking Nanozyme with Enhanced Activity and High Stability Based on Metal-Support Interactions.

Science.gov (United States)

Li, Zhihao; Yang, Xiangdong; Yang, Yanbing; Tan, Yaning; He, Yue; Liu, Meng; Liu, Xinwen; Yuan, Quan

2018-01-09

Peroxidase-mimicking nanozymes offer unique advantages in terms of high stability and low cost over natural peroxidase for applications in bioanalysis, biomedicine, and the treatment of pollution. However, the design of high-efficiency peroxidase-mimicking nanozymes remains a great challenge. In this study, we adopted a structural-design approach through hybridization of cube-CeO 2 and Pt nanoparticles to create a new peroxidase-mimicking nanozyme with high efficiency and excellent stability. Relative to pure cube-CeO 2 and Pt nanoparticles, the as-hybridized Pt/cube-CeO 2 nanocomposites display much improved activities because of the strong metal-support interaction. Meanwhile, the nanocomposites also maintain high catalytic activity after long-term storage and multiple recycling. Based on their excellent properties, Pt/cube-CeO 2 nanocomposites were used to construct high-performance colorimetric biosensors for the sensitive detection of metabolites, including H 2 O 2 and glucose. Our findings highlight opportunities for the development of high-efficiency peroxidase-mimicking nanozymes with potential applications such as diagnostics, biomedicine, and the treatment of pollution. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Parametric Study on the Thermal Performance and Optimal Design Elements of Solar Air Heater Enhanced with Jet Impingement on a Corrugated Absorber Plate

Directory of Open Access Journals (Sweden)

Alsanossi M. Aboghrara

2018-01-01

Full Text Available Previous works revealed that cross-corrugated absorber plate design and jet impingement on a flat absorber plate resulted in a significant increase in the performance of a solar air heater (SAH. Involving these two designs into one continuous design to improve the SAH performance remains absent in the literature. This study aimed to evaluate the achieved enhancement on performance parameters of a SAH with jet impingement on a corrugated absorber plate. An energy balance model was developed to compare the performance parameters of the proposed SAH with the other two SAHs. At a clear sky day and a mass flow rate of 0.04 kg/s, the hourly results revealed that the max fluid outlet temperatures for the proposed SAH, jet-to-flat plate SAH, and cross-corrugated plate SAH are 321, 317, and 313 K, respectively; the max absorber plate temperatures are 323.5, 326.5, and 328 K, respectively; the maximum temperature differences between the absorber plate and fluid outlet are ~3, 9, and 15 K, respectively; the max efficiencies are 65.7, 64.8, and 60%, respectively. Statistical t-test results confirmed significant differences between the mean efficiency of the proposed SAH and SAH with jet-to-flat plate. Hence, the proposed design is considered superior in improving the performance parameters of SAH compared to other designs.

Mycobacterium intracellulare Infection Mimicking Progression of Scleroderma

DEFF Research Database (Denmark)

Krabbe, Simon; Engelhart, Merete; Thybo, Sören

2017-01-01

This case report describes a patient with scleroderma who developed Mycobacterium intracellulare infection, which for more than a year mimicked worsening of her connective tissue disorder. The patient was diagnosed with scleroderma based on puffy fingers that developed into sclerodactyly, abnormal......, unfortunately with significant scarring. Immunodeficiency testing was unremarkable. In summary, an infection with Mycobacterium intracellulare was mistaken for an unusually severe progression of scleroderma....

Experimental and numerical investigations of the impingement of an oblique liquid jet onto a superhydrophobic surface: energy transformation

Energy Technology Data Exchange (ETDEWEB)

Kibar, Ali, E-mail: alikibar@kocaeli.edu.tr [Department of Mechanical and Material Technologies, Kocaeli University, 41285, Arslanbey Campus, Kocaeli (Turkey)

2016-02-15

This study presents the theory of impinging an oblique liquid jet onto a vertical superhydrophobic surface based on both experimental and numerical results. A Brassica oleracea leaf with a 160° apparent contact angle was used for the superhydrophobic surface. Distilled water was sent onto the vertical superhydrophobic surface in the range of 1750–3050 Reynolds number, with an inclination angle of 20°−40°, using a circular glass tube with a 1.75 mm inner diameter. The impinging liquid jet spread onto the surface governed by the inertia of the liquid and then reflected off the superhydrophobic surface due to the surface energy of the spreading liquid. Two different energy approaches, which have time-scale and per-unit length, were performed to determine transformation of the energy. The kinetic energy of the impinging liquid jet was transformed into the surface energy with an increasing interfacial surface area between the liquid and air during spreading. Afterwards, this surface energy of the spreading liquid was transformed into the reflection kinetic energy. (paper)

Survey of fish impingement at power plants in the United States. Volume II. Inland waters

International Nuclear Information System (INIS)

Freeman, R.F. III; Sharma, R.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

Fish-inspired self-powered microelectromechanical flow sensor with biomimetic hydrogel cupula

Science.gov (United States)

Bora, M.; Kottapalli, A. G. P.; Miao, J. M.; Triantafyllou, M. S.

2017-10-01

Flow sensors inspired from lateral line neuromasts of cavefish have been widely investigated over decades to develop artificial sensors. The design and function of these natural sensors have been mimicked using microelectromechanical systems (MEMS) based sensors. However, there is more to the overall function and performance of these natural sensors. Mimicking the morphology and material properties of specialized structures like a cupula would significantly help to improve the existing designs. Toward this goal, the paper reports development of a canal neuromast inspired piezoelectric sensor and investigates the role of a biomimetic cupula in influencing the performance of the sensor. The sensor was developed using microfabrication technology and tested for the detection of the steady-state and oscillatory flows. An artificial cupula was synthesized using a soft hydrogel material and characterized for morphology and mechanical properties. Results show that the artificial cupula had a porous structure and high mechanical strength similar to the biological canal neuromast. Experimental results show the ability of these sensors to measure the steady-state flows accurately, and for oscillatory flows, an increase in the sensor output was detected in the presence of the cupula structure. This is the first time a MEMS based piezoelectric sensor is demonstrated to detect steady-state flows using the principle of vortex-induced vibrations. The bioinspired sensor developed in this work would be investigated further to understand the role of the cupula structure in biological flow sensing mechanisms, thus contributing toward the design of highly sensitive and efficient sensors for various applications such as underwater robotics, microfluidics, and biomedical devices.

Interaction of Liquid Film Flow of Direct Vessel Injection Under the Cross Directional Gas Flow

Energy Technology Data Exchange (ETDEWEB)

Kim, Han-sol; Lee, Jae-young [Handong Global University, Pohang (Korea, Republic of); Euh, Dong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

In order to obtain a proper scaling law of the flow, local information of the flow was investigated experimentally and also numerically. A series of experiments were conducted in the 1/20 modified linear scaled plate type test rig to analyze a liquid film from ECC water injection through the DVI nozzle to the downcomer wall. The present study investigates liquid film flow generated in a downcomer of direct vessel injection (DVI) system which is employed as an emergency core cooling (ECC) system during a loss of coolant accident in the Korea nuclear power plant APR1400. During the late reflooding, complicated multi-phase flow phenomena including the wavy film flow, film breakup, entrainment, liquid film shift due to interfacial drag and gas jet impingement occur. A confocal chromatic sensor was used to measure the local instantaneous liquid film thickness and a hydraulic jump in the film flow and boundaries of the film flow. It was found that CFD analysis results without surface tension model showed some difference with the data in surface tension dominated flow region. For the interaction between a liquid film and gas shear flow, CFD results make a good agreement with the real liquid film dynamics in the case of low film Reynolds number or low Weber number flow. In the 1/20 scaled plate type experiment and simulation, the deformed spreading profile results seem to accord with each other at the relatively low We and Re regime.

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.

Impinging Water Droplets on Inclined Glass Surfaces

Energy Technology Data Exchange (ETDEWEB)

Armijo, Kenneth Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lance, Blake [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ho, Clifford K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

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 (0°, 10°, and 45°), droplet velocities (1 m/s and 3 m/s), and wetting characteristics (wetting=47° contact angle and non-wetting = 93° 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 ~3 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 45° 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

Effects of mimicking: Acting prosocially by being emotionally moved

NARCIS (Netherlands)

Stel, M.; Baaren, R.B. van; Vonk, R.

2008-01-01

Mimicry is functional for empathy and bonding purposes. Studies on the consequences of mimicry at a behavioral level demonstrated that mimicry increases prosocial behavior. However, these previous studies focused on the mimickee. In the present paper, we investigated whether mimickers also become

MR-imaging of anterior tibiotalar impingement syndrome: Agreement, sensitivity and specificity of MR-imaging and indirect MR-arthrography

Energy Technology Data Exchange (ETDEWEB)

Haller, Joerg [Department of Radiology, Hanusch Hospital, Heinrich Collin-Strasse 30, A-1140 Vienna (Austria); Ludwig Boltzmann Institute for Osteology, Hanusch Hospital, Heinrich Collin-Strasse 30, A-1140 Vienna (Austria); Bernt, Reinhard [Department of Radiology, Hanusch Hospital, Heinrich Collin-Strasse 30, A-1140 Vienna (Austria)]. E-mail: reinhard.bernt@wgkk.sozvers.at; Seeger, Thomas [Department of Trauma Surgery, Hanusch Hospital, Heinrich Collin-Strasse 30, A-1140 Vienna (Austria); Weissenbaeck, Alexander [Department of Trauma Surgery, Hanusch Hospital, Heinrich Collin-Strasse 30, A-1140 Vienna (Austria); Tuechler, Heinrich [Ludwig Boltzmann Institute for Hematology, Hanusch Hospital, Heinrich Collin-Strasse 30, A-1140 Vienna (Austria); Resnick, Donald [Department of Radiology, VA Medical Center, UCSD, 3350 La Jolla Village Dr, San Diego, CA 92161 (United States)

2006-06-15

Objective: To clarify the role of MR-imaging in the diagnosis of anterior ankle impingement syndromes. Materials and methods: We prospectively examined 51 consecutive patients with chronic ankle pain by MR-imaging. Arthroscopy was performed in 29 patients who previously underwent non-enhanced MR-imaging; in 11 patients, indirect MR-arthrography additionally was performed. MR-examinations were correlated with clinical findings; MR and arthroscopy scores were statistically compared, agreement was measured. Results: Arthroscopy demonstrated granulation tissue in the lateral gutter (38%) and anterior recess (31%), lesions of the anterior tibiofibular (31%) and the anterior talofibular ligament (21%) as well as intraarticular bodies (10%). Stenosing tenosynovitis and a ganglionic cyst were revealed as extraarticular causes for chronic ankle pain by MR-examination (17%). Agreement of MR-imaging and arthroscopy was fair for the anterior talofibular ligament and the anterior joint cavity (kappa 0.40). Major discrepancy was found for non-enhanced MR scans (kappa 0.49) when compared with indirect MR-arthrography (kappa 0.03) in the anterior cavity. The sensitivity for lesions of the anterior talofibular and calcaneofibular ligament and the anterior cavity (0.91-0.87) detected by MR-imaging was superior in comparison to lesions of the anterior tibiofibular ligament and anteromedial cavity (0.50-0.24). Conclusion: MR-imaging provides additional information about the mechanics of chronic ankle impingement rather than an accurate diagnosis of this clinical entity. The method is helpful in differentiating extra- from intra-articular causes of ankle impingement. Indirect MR-arthrography has little or no additional value in patients with ankle impingement syndrome.

MR-imaging of anterior tibiotalar impingement syndrome: Agreement, sensitivity and specificity of MR-imaging and indirect MR-arthrography

International Nuclear Information System (INIS)

Haller, Joerg; Bernt, Reinhard; Seeger, Thomas; Weissenbaeck, Alexander; Tuechler, Heinrich; Resnick, Donald

2006-01-01

Objective: To clarify the role of MR-imaging in the diagnosis of anterior ankle impingement syndromes. Materials and methods: We prospectively examined 51 consecutive patients with chronic ankle pain by MR-imaging. Arthroscopy was performed in 29 patients who previously underwent non-enhanced MR-imaging; in 11 patients, indirect MR-arthrography additionally was performed. MR-examinations were correlated with clinical findings; MR and arthroscopy scores were statistically compared, agreement was measured. Results: Arthroscopy demonstrated granulation tissue in the lateral gutter (38%) and anterior recess (31%), lesions of the anterior tibiofibular (31%) and the anterior talofibular ligament (21%) as well as intraarticular bodies (10%). Stenosing tenosynovitis and a ganglionic cyst were revealed as extraarticular causes for chronic ankle pain by MR-examination (17%). Agreement of MR-imaging and arthroscopy was fair for the anterior talofibular ligament and the anterior joint cavity (kappa 0.40). Major discrepancy was found for non-enhanced MR scans (kappa 0.49) when compared with indirect MR-arthrography (kappa 0.03) in the anterior cavity. The sensitivity for lesions of the anterior talofibular and calcaneofibular ligament and the anterior cavity (0.91-0.87) detected by MR-imaging was superior in comparison to lesions of the anterior tibiofibular ligament and anteromedial cavity (0.50-0.24). Conclusion: MR-imaging provides additional information about the mechanics of chronic ankle impingement rather than an accurate diagnosis of this clinical entity. The method is helpful in differentiating extra- from intra-articular causes of ankle impingement. Indirect MR-arthrography has little or no additional value in patients with ankle impingement syndrome

Endometriosis of the mesoappendix mimicking appendicitis: A case report

Directory of Open Access Journals (Sweden)

Suman Mewa Kinoo

2016-09-01

Full Text Available Although appendicitis is largely a clinical diagnosis, on occasions diagnostic modalities may be needed to aid with the diagnosis. Despite the use of adjuncts and exploratory surgery, the diagnosis may not be clear until a histological diagnosis is achieved. Endometriosis of the appendix mimicking appendicitis is one of these diagnoses described in several case reports. Endometriosis of the meso-appendix has been described in association with intussusception of the appendix in several case reports. However, to our knowledge, endometriosis of the meso-appendix mimicking appendicitis has not been reported to date. We present the case of a 33-year-old woman with classic clinical signs and symptoms of appendicitis endorsed on computed tomography imaging. The patient underwent a laparoscopic appendicectomy with the postoperative histology demonstrating a normal appendix with endometriosis of the meso-appendix.

Extracapsular approach for arthroscopic treatment of femoroacetabular impingement: clinical and radiographic results and complications

Directory of Open Access Journals (Sweden)

Bruno Dutra Roos

2015-08-01

Full Text Available ABSTRACTOBJECTIVES: To evaluate the clinical and radiographic results and complications relating to patients undergoing arthroscopic treatment for femoroacetabular impingement by means of an extracapsular approach. METHODS: Between January 2011 and March 2012, 49 patients (50 hips underwent arthroscopic treatment for femoroacetabular impingement, performed by the hip surgery team of the Orthopedic Hospital of Passo Fundo, Rio Grande do Sul. Forty patients (41 hips fulfilled all the requirements for this study. The mean follow-up was 29.1 months. The patients were assessed clinically by means of the Harris Hip score, as modified by Byrd (MHHS, the Non-Arthritic Hip score (NAHS and the internal rotation of the hip. Their hips were also evaluated radiographically, with measurement of the CE angle, dimensions of the joint space, alpha angle, neck-head index, degree of arthrosis and presence of heterotopic ossification of the hip. RESULTS: Out of the 41 hips treated, 31 (75.6% presented good or excellent clinical results. There was a mean postoperative increase of 22.1 points for the MHHS, 21.5 for the NAHS and 16.4° for the internal rotation of the hip ( p< 0.001. Regarding the radiographic evaluation, correction to normal values was observed for the alpha angle and neck-head index, with a mean postoperative decrease of 32.9° and mean increase of 0.10, respectively ( p< 0.001. CONCLUSION: Arthroscopic treatment of femoroacetabular impingement by means of an extracapsular approach presented satisfactory clinical and radiographic results over a mean follow-up of 29.1 months, with few complications.

Tension pneumocephalus mimicking septic shock: a case report

Directory of Open Access Journals (Sweden)

Caroline Miranda, MD

2018-02-01

Full Text Available Tension pneumocephalus can lead to rapid neurologic deterioration. We report for the first time its association with aseptic systemic inflammatory response syndrome mimicking septic shock and the efficacy of prompt neurosurgical intervention and critical care support in treating this condition. A 64-year-old man underwent 2-stage olfactory groove meningioma resection. The patient developed altered mental status and gait instability on postoperative day 6. Imaging showed significant pneumocephalus. The patient subsequently developed worsening mental status, respiratory failure, and profound shock requiring multiple vasopressors. Bedside needle decompression, identification and repair of the cranial fossa defect, and critical care support led to improved mental status and reversal of shock and multiorgan dysfunction. Thorough evaluation revealed no evidence of an underlying infection. In this case, tension pneumocephalus incited an aseptic systemic inflammatory response syndrome mimicking septic shock. Prompt neurosurgical correction of pneumocephalus and critical care support not only improved neurologic status, but also reversed shock. Such a complication indicates the importance of close monitoring of patients with progressive pneumocephalus.

A mountain among molehills: removing an impinging large femoral neck osteochondroma in a man with hereditary multiple exostoses.

LENUS (Irish Health Repository)

Fitzgerald, Conall W R

2014-01-01

A 31-year-old man with a history of hereditary multiple exostoses (HME) presented with persistent right groin pain and reduced hip range of movement. Examination demonstrated a positive FADIR (flexion, adduction and internal rotation) test suggesting femoroacetabular impingement (FAI). Investigations showed multiple sessile osteochondromata of the right femur with a dominant anterolateral femoral neck osteochondroma causing flexion block. The patient underwent an uncomplicated proximal femoral exostectomy. Six-week postoperative pain, range of movement and daily activity had greatly improved. This case highlights that even in the setting of multiple osteochondromata, excellent impingement relief can be achieved following selective proximal femoral exostectomy.

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.

Os acromiale causing shoulder impingement syndrome: a case report

International Nuclear Information System (INIS)

Romero, I.; Rodriguez, A.; Roca, M.; Garcia, Y.

2001-01-01

Shoulder impingement syndrome is caused by repeated mechanical trauma to the rotator cuff due to encroachment of the coracoacromial ligament; 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

Survey of fish impingement at power plants in the United States. Volume I. The Great Lakes

International Nuclear Information System (INIS)

Sharma, R.K.; Freeman, R.F. III.

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

A combined CFD-experimental method for developing an erosion equation for both gas-sand and liquid-sand flows

Science.gov (United States)

Mansouri, Amir

The surface degradation of equipment due to consecutive impacts of abrasive particles carried by fluid flow is called solid particle erosion. Solid particle erosion occurs in many industries including oil and gas. In order to prevent abrupt failures and costly repairs, it is essential to predict the erosion rate and identify the locations of the equipment that are mostly at risk. Computational Fluid Dynamics (CFD) is a powerful tool for predicting the erosion rate. Erosion prediction using CFD analysis includes three steps: (1) obtaining flow solution, (2) particle tracking and calculating the particle impact speed and angle, and (3) relating the particle impact information to mass loss of material through an erosion equation. Erosion equations are commonly generated using dry impingement jet tests (sand-air), since the particle impact speed and angle are assumed not to deviate from conditions in the jet. However, in slurry flows, a wide range of particle impact speeds and angles are produced in a single slurry jet test with liquid and sand particles. In this study, a novel and combined CFD/experimental method for developing an erosion equation in slurry flows is presented. In this method, a CFD analysis is used to characterize the particle impact speed, angle, and impact rate at specific locations on the test sample. Then, the particle impact data are related to the measured erosion depth to achieve an erosion equation from submerged testing. Traditionally, it was assumed that the erosion equation developed based on gas testing can be used for both gas-sand and liquid-sand flows. The erosion equations developed in this work were implemented in a CFD code, and CFD predictions were validated for various test conditions. It was shown that the erosion equation developed based on slurry tests can significantly improve the local thickness loss prediction in slurry flows. Finally, a generalized erosion equation is proposed which can be used to predict the erosion rate in

Evaluation of liquid droplet impingement erosion by micro-scale fracture analysis

International Nuclear Information System (INIS)

Kitajima, Yasumi; Hagiwara, Tsuyoshi; Jimbo, Masakazu; Endo, Tetsuo

2008-01-01

Several estimation methods based on round-robin experiments and/or actual plant experiences have been used to estimate erosion by liquid drop impingement (LDI). However, in recent years, due to developments on computer technology, it is possible to utilize large scale computational analyses. This study proposes a method for the evaluation of LDI erosion by means of computational fracture analysis using results (diameters, velocity, or speed of drops) of fluid dynamics analysis. (author)

Studies on Impingement Effects of Low Density Jets on Surfaces — Determination of Shear Stress and Normal Pressure

Science.gov (United States)

Sathian, Sarith. P.; Kurian, Job

2005-05-01

This paper presents the results of the Laser Reflection Method (LRM) for the determination of shear stress due to impingement of low-density free jets on flat plate. For thin oil film moving under the action of aerodynamic boundary layer the shear stress at the air-oil interface is equal to the shear stress between the surface and air. A direct and dynamic measurement of the oil film slope is measured using a position sensing detector (PSD). The thinning rate of oil film is directly measured which is the major advantage of the LRM over LISF method. From the oil film slope history, direct calculation of the shear stress is done using a three-point formula. For the full range of experiment conditions Knudsen numbers varied till the continuum limit of the transition regime. The shear stress values for low-density flows in the transition regime are thus obtained using LRM and the measured values of shear show fair agreement with those obtained by other methods. Results of the normal pressure measurements on a flat plate in low-density jets by using thermistors as pressure sensors are also presented in the paper. The normal pressure profiles obtained show the characteristic features of Newtonian impact theory for hypersonic flows.

Secondary Subacromial Impingement after Valgus Closing-Wedge Osteotomy for Proximal Humerus Varus

Directory of Open Access Journals (Sweden)

Hirotaka Sano

2015-01-01

Full Text Available A 31-year-old construction worker had been suffering from both the motion pain and the restriction of elevation in his right shoulder due to severe varus deformity of humeral neck, which occurred after proximal humeral fracture. The angle for shoulder flexion and abduction was restricted to 50 and 80 degrees, respectively. Valgus closing-wedge osteotomy followed by the internal fixation using a locking plate was carried out at 12 months after injury. Postoperatively, the head-shaft angle of the humerus improved from 65 to 138 degrees. Active flexion and abduction angles improved from 80 to 135 degrees and from 50 to 135 degrees, respectively. However, the patient complained from a sharp pain with a clicking sound during shoulder abduction even after removal of the locking plate. Since subacromial steroid injection temporarily relieved his shoulder pain, we assumed that the secondary subacromial impingement was provoked after osteotomy. Thus, arthroscopic subacromial decompression was carried out at 27 months after the initial operation, which finally relieved his symptoms. In the valgus closing-wedge osteotomy, surgeons should pay attention to the condition of subacromial space to avoid causing the secondary subacromial impingement.

Brown tumor mimicking maxillary sinus mucocele as the first manifestation of primary hyperparathyroidism

DEFF Research Database (Denmark)

Guldfred, Liviu-Adelin; Daugaard, Søren; von Buchwald, Christian

2012-01-01

We describe the first case of brown tumor mimicking a maxillary sinus mucocele as the first manifestation of the patient's primary hyperparathyroidism. A 34-year old woman presented with a 14 days history of elevation of the right orbit, retrobulbar pain and cheek anesthesia. The CT and MR evalua...... either giant cell granuloma or brown tumor. The finding of hyperparathyroidism confirmed the diagnosis of brown tumor. To our knowledge, this is the first report of cystic brown tumor mimicking a mucocele of the maxillary sinus....

Levitation of a drop over a film flow

Science.gov (United States)

Sreenivas, K. R.; de, P. K.; Arakeri, Jaywant H.

1999-02-01

A vertical jet of water impinging on a horizontal surface produces a radial film flow followed by a circular hydraulic jump. We report a phenomenon where fairly large (1 ml) drops of liquid levitate just upstream of the jump on a thin air layer between the drop and the film flow. We explain the phenomenon using lubrication theory. Bearing action both in the air film and the water film seems to be necessary to support large drops. Horizontal support is given to the drop by the hydraulic jump. A variety of drop shapes is observed depending on the volume of the drop and liquid properties. We show that interaction of the forces due to gravity, surface tension, viscosity and inertia produces these various shapes.

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.

Preoperative conventional magnetic resonance images versus magnetic resonance arthrography of subacromial impingement syndrome

International Nuclear Information System (INIS)

Ahn, Sang Hyuk; Park, Jung Hwan; Moon, Tae Yong; Lee, In Sook; Lee, Seung Jun

2012-01-01

To evaluate the usefulness of conventional magnetic resonance images (MRI) for arthroscopic surgery in subacromial impingement syndrome of the shoulder, as an alternative to MR arthrography with additional T2 fat saturation images (MRA). The preoperative MRI of 77 patients (45 females, 32 males) (52 right, 25 left) and MRA of 34 patients (14 females, 20 males) (24 right, 10 left) with subsequent arthroscopic confirmation of subacromial impingement syndrome were reviewed retrospectively. The lesions requiring arthroscopic surgery were 95 subacromial spurs, 101 subacromial bursitis, and 51 full-thickness and 44 partial thickness tears of the supraspinatus among 111 cases for both studies. A two by two table was constructed in order to calculate the sensitivity and specificity of both studies against arthroscopic outcomes. Also we analyzed the false positive and false negative cases of the full-thickness tears individually. The detection rates of subacromial spur and bursitis and full and partial thickness tears of the supraspinatus were 91%, 94%, 77%, and 65% in MRI and 93%, 100%, 83%, and 77% in MRA respectively. Their specificities were 33%, 33%, 90%, and 76% in MRI and 50%, 75%, 100%, and 71% in MRA respectively. Eleven false negative cases in regards to MRI resulted in Ellman's grade 3 partial thickness tear (72.7%), mild bursitis (63.6%), greater tuberosity erosion (45.5%), and negative fluid signal of the glenohumeral joint (81.8%). Three false positive cases on the MRI were induced from errors with lower window depth and width on the imagings. Two false negative cases on MRA were induced from the adhesion between Ellman's grade 3 rim rent tear and the glenohumeral joint cavity. Conventional MR images could be used to decide the arthroscopic surgery in subacromial impingement syndrome, as an alternative to MR arthrography with additional T2 fat saturation images

The effect of dynamic femoroacetabular impingement on pubic symphysis motion: a cadaveric study.

Science.gov (United States)

Birmingham, Patrick M; Kelly, Bryan T; Jacobs, Robert; McGrady, Linda; Wang, Mei

2012-05-01

A link between femoroacetabular impingement and athletic pubalgia has been reported clinically. One proposed origin of athletic pubalgia is secondary to repetitive loading of the pubic symphysis, leading to instability and parasymphyseal tendon and ligament injury. Hypothesis/ The purpose of this study was to investigate the effect of simulated femoral-based femoroacetabular impingement on rotational motion at the pubic symphysis. The authors hypothesize that the presence of a cam lesion leads to increased relative symphyseal motion. Controlled laboratory study. Twelve hips from 6 fresh-frozen human cadaveric pelvises were used to simulate cam-type femoroacetabular impingement. The hips were held in a custom jig and maximally internally rotated at 90° of flexion and neutral adduction. Three-dimensional motion of the pubic symphysis was measured by a motion-tracking system for 2 states: native and simulated cam. Load-displacement plots were generated between the internal rotational torque applied to the hip and the responding motion in 3 anatomic planes of the pubic symphysis. As the hip was internally rotated, the motion at the pubic symphysis increased proportionally with the degrees of the rotation as well as the applied torque measured at the distal femur for both states. The primary rotation of the symphysis was in the transverse plane and on average accounted for more than 60% of the total rotation. This primary motion caused the anterior aspect of the symphyseal joint to open or widen, whereas the posterior aspect narrowed. At the torque level of 18.0 N·m, the mean transverse rotation in degrees was 0.89° ± 0.35° for the native state and 1.20° ± 0.41° for cam state. The difference between cam and the native groups was statistically significant (P pubalgia.

Preoperative conventional magnetic resonance images versus magnetic resonance arthrography of subacromial impingement syndrome

Energy Technology Data Exchange (ETDEWEB)

Ahn, Sang Hyuk; Park, Jung Hwan; Moon, Tae Yong [Pusan National Univ. Yangsan Hospital, Yangsan (Korea, Republic of); Lee, In Sook; Lee, Seung Jun [Pusan National Univ. Hospital, Busan (Korea, Republic of)

2012-09-15

To evaluate the usefulness of conventional magnetic resonance images (MRI) for arthroscopic surgery in subacromial impingement syndrome of the shoulder, as an alternative to MR arthrography with additional T2 fat saturation images (MRA). The preoperative MRI of 77 patients (45 females, 32 males) (52 right, 25 left) and MRA of 34 patients (14 females, 20 males) (24 right, 10 left) with subsequent arthroscopic confirmation of subacromial impingement syndrome were reviewed retrospectively. The lesions requiring arthroscopic surgery were 95 subacromial spurs, 101 subacromial bursitis, and 51 full-thickness and 44 partial thickness tears of the supraspinatus among 111 cases for both studies. A two by two table was constructed in order to calculate the sensitivity and specificity of both studies against arthroscopic outcomes. Also we analyzed the false positive and false negative cases of the full-thickness tears individually. The detection rates of subacromial spur and bursitis and full and partial thickness tears of the supraspinatus were 91%, 94%, 77%, and 65% in MRI and 93%, 100%, 83%, and 77% in MRA respectively. Their specificities were 33%, 33%, 90%, and 76% in MRI and 50%, 75%, 100%, and 71% in MRA respectively. Eleven false negative cases in regards to MRI resulted in Ellman's grade 3 partial thickness tear (72.7%), mild bursitis (63.6%), greater tuberosity erosion (45.5%), and negative fluid signal of the glenohumeral joint (81.8%). Three false positive cases on the MRI were induced from errors with lower window depth and width on the imagings. Two false negative cases on MRA were induced from the adhesion between Ellman's grade 3 rim rent tear and the glenohumeral joint cavity. Conventional MR images could be used to decide the arthroscopic surgery in subacromial impingement syndrome, as an alternative to MR arthrography with additional T2 fat saturation images.

Impingement heat/mass transfer to hybrid synthetic jets and other reversible pulsating jets

Czech Academy of Sciences Publication Activity Database

Trávníček, Zdeněk; Vít, T.

2015-01-01

Roč. 85, June (2015), s. 473-487 ISSN 0017-9310 R&D Projects: GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : impinging jet * reversible pulsating jet * synthetic jet Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts Impact factor: 2.857, year: 2015 http://www.sciencedirect.com/science/article/pii/S001793101500143X

Experimental study of the turbulent flow around a single wall-mounted cube exposed to a cross-flow and an impinging jet

International Nuclear Information System (INIS)

Masip, Yunesky; Rivas, Alejandro; Larraona, Gorka S.; Anton, Raúl; Ramos, Juan Carlos; Moshfegh, Bahram

2012-01-01

Highlights: ► We measured the instantaneous flow velocity using 2D-Particle Image Velocimetry. ► Recirculation bubbles, vortices, detachment and reattachment zones are showed. ► The influence of the Re H and Re j /Re H was studied. ► The Re j /Re H determines the effects produced around the component. - Abstract: The air flow around a cubic obstacle mounted on one wall of a rectangular channel was studied experimentally. The obstacle represents an electronic component and the channel the space between two parallel printed circuit boards (PCBs). The flow was produced by the combination of a channel stream and a jet which issued from a circular nozzle placed at the wall opposite from where the component is mounted. With this aim, a test rig was designed and built to carry out experiments with both the above mentioned configurations and other cooling arrangements. Planar Particle Image Velocimetry (PIV) was employed to measure the instantaneous flow velocity on several planes covering the space around the component. The mean velocity and the Reynolds stresses were obtained from averaging the instantaneous velocity, and the mean flow showed a complex pattern with different features such as recirculation bubbles, vortices, detachment and reattachment zones. The influence of two parameters, namely the channel Reynolds number and the jet-to-channel Reynolds number ratio, on these flow features was studied considering nine cases that combined three values of the channel Reynolds number (3410, 5752 and 8880) and three values of the ratio (0.5, 1.0 and 1.5). The results show that the Reynolds number ratio determines the drag produced on the jet and the deflection from its geometric axis due to the channel stream. In all the cases corresponding to the lowest value of the ratio, the jet was dragged and did not impact the component. This fact accounts for the non-existence of the Upper Horseshoe Vortex and changes in the flow characteristics at the region over the

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

Ultrasound measurement of rotator cuff thickness and acromio-humeral distance in the diagnosis of subacromial impingement syndrome of the shoulder.

Science.gov (United States)

Cholewinski, Jerzy J; Kusz, Damian J; Wojciechowski, Piotr; Cielinski, Lukasz S; Zoladz, Miroslaw P

2008-04-01

The usefulness of ultrasound measurements in the diagnosis of the subacromial impingement syndrome of the shoulder was evaluated. Fifty-seven patients with unilateral symptoms of the impingement syndrome underwent ultrasound examination of both shoulder joints, which included assessment of rotator cuff integrity, measurement of rotator cuff thickness and the distance between the infero-lateral edge of acromion and the apex of the greater tuberosity of humerus (AGT distance) in the standard ultrasonographic positions. As a control group, 36 volunteers (72 shoulders) with no history of shoulder pain were examined sonographically. Ultrasonographic assessment of humeral head elevation, measured as the AGT distance, proved to be useful in establishing the diagnosis of the subacromial impingement syndrome of the shoulder. A difference in rotator cuff thickness of more than 1.1 mm and a difference in the AGT distance of more than 2.1 mm between both shoulder joints may reflect dysfunction of rotator cuff muscles.

Bio-Inspired PVDF-Based, Mouse Whisker Mimicking, Tactile Sensor

Directory of Open Access Journals (Sweden)

Mohsin Islam Tiwana

2016-10-01

Full Text Available The design and fabrication of a Polyvinylidene fluoride (PVDF based, mouse (or rodent whisker mimicking, tactile sensor is presented. Unlike previous designs reported in the literature, this sensor mimics the mouse whisker not only mechanically, but it also makes macro movements just like a real mouse whisker in a natural environment. We have developed a mathematical model and performed finite element analysis using COMSOL, in order to optimise the whisker to have the same natural frequency as that of a biological whisker. Similarly, we have developed a control system that enables the whisker mimicking sensor to vibrate at variable frequencies and conducted practical experiments to validate the response of the sensor. The natural frequency of the whisker can be designed anywhere between 35 and 110 Hz, the same as a biological whisker, by choosing different materials and physical dimensions. The control system of this sensor enables the whisker to vibrate between 5 and 236 Hz.

Large and Small Droplet Impingement Data on Airfoils and Two Simulated Ice Shapes

Science.gov (United States)

Papadakis, Michael; Wong, See-Cheuk; Rachman, Arief; 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 four wings and one wing with two simulated ice shapes. The wings tested include three 36-in. chord wings (MS(1)-317, GLC-305, and a NACA 652-415) and a 57-in. chord Twin Otter horizontal tail section. The simulated ice shapes were 22.5- and 45-min glaze ice shapes for the Twin Otter horizontal tail section generated using the LEWICE 2.2 ice accretion program. The impingement experiments were performed with spray clouds having median volumetric diameters of 11, 21, 79, 137, and 168 mm. Comparisons to the experimental data were generated which showed good agreement for the clean wings and ice shapes at lower drop sizes. For larger drop 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 and shadow regions of ice shapes.

Instrumentation to Monitor Transient Periodic Developing Flow in Non-Newtonian Slurries

Energy Technology Data Exchange (ETDEWEB)

Bamberger, Judith A.; Enderlin, Carl W.

2013-11-15

Staff at Pacific Northwest National Laboratory have conducted mixing and mobilization experiments with non-Newtonian slurries that exhibit Bingham plastic and shear thinning behavior and shear strength. This paper describes measurement techniques applied to identify the interface between flowing and stationary regions of non-Newtonian slurries that are subjected to transient, periodic, developing flows. Techniques were developed to identify the boundary between the flowing and stationary regions, time to mix, characteristic velocities of the flow field produced by the symmetrically spaced nozzles, and the velocity of the upwell formed in the center of the tank by the intersection of flow from four symmetrically spaced nozzles that impinge upon the tank floor. Descriptions of the instruments and instrument performance are presented. These techniques were an effective approach to characterize mixing phenomena, determine mixing energy required to fully mobilize vessel contents and to determine mixing times for process evaluation.

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.

[The relationship between chronic hip pain and femoroacetabular impingement: an evaluation with clinical signs and radiography].

Science.gov (United States)

Sahin, Namik; Atici, Teoman; Oztürk, Alpaslan; Ozkaya, Güven; Avcu, Bülent; Ozkan, Yüksel

2011-12-01

In this study, we investigated the rate of the clinical and radiographic findings of femoroacetabular impingement (FAI) in patients with chronic hip pain and compared the findings with those of a control group. The clinical and radiographic findings of FAI in 38 patients (group 1) having hip pain for more than three months were analyzed and compared with 42 controls (group 2). Internal rotation degrees were measured while the hips were at 90° flexion and impingement test was performed by rotating the hips internally at 90° flexion and adduction. The FAI findings were investigated on anteroposterior pelvis radiographs and cross-table lateral radiographs of the hip joint in both groups. The collum-diaphyseal angle, alpha angle and anterior offset ratio on the femoral side and the center-edge angle, acetabular index, extrusion index and crossover sign on the acetabular side were evaluated. The internal rotation degree of the painful hips were less than 20 degree in 18 (47.4%) patients in group 1 and in one (2.4%) patient in group 2 (pcam type FAI was 76.3% (n=29) in group 1 and 42.9% (n=18) in group 2 (p=0.002). Femoroacetabular impingement is one of the causes of chronic hip pain and if evaluated with suitable clinical and radiographic parameters, the rates of diagnosis may increase.

The Effect of Platelet-Rich Plasma (PRP on Improvement in Pain and Symptoms of Shoulder Subacromial Impingement Syndrome

Directory of Open Access Journals (Sweden)

Parisa Nejati

2015-08-01

Full Text Available Abstract Background: Subacromial impingement is one of the most common complaints of shoulder. Treatments include avoiding of painful activities, oral anti-pain drugs, physical therapy modalities, corticosteroid injection and exercise therapy. Some studies have shown that platelet- rich plasma(PRP is effective on tendinitis and tearing of tendons, ligaments and muscles, but evidence that has proved PRP as a conservative treatment in shoulder pathologies is very limited. This study aims to investigate the effect of PRP injection on relieving pain and improving daily function of patients with shoulder impingement syndrome. Materials and Methods: In this clinical trial study, patients older than 40 with pain more than three months were included. If they had three of four positive diagnostic clinical tests of shoulder impingement that were confirmed by shoulder MRI, could be injected PRP twice. The time between injections was 1 month. Pain was measured by visual analog scale (VAS and function was measured by two questionnaires named disabilities of the arm, shoulder and hand (DASH and western Ontario rotator cuff index (WORC. Range of motion (ROM of shoulder was measured in five directions by goniometry . All of these parameters were evaluated before intervention and in 1, 3, 6 months later. Results: with due attention to a six-month folloe-up, PRR injection was effective in pain reduction and improvement of patient's function (p<0.05. Shoulder Rom increased in all directions except external rotation and the power of shoulder muscles was evidently improved statistically in flexion, abduction and internal toration. Conclusion: PRP injection could effectively reduce pain and improve daily activities in patients with shoulder impingement syndrome.

Experimental investigation of impingement cooling with turbulators or surface enlarging elements

Energy Technology Data Exchange (ETDEWEB)

Persson, Johan

2000-02-01

For the materials in modern gas turbines to sustain, a considerable amount of cooling is required. In cases where large amounts of heat need to be removed, impingement cooling with its high heat transfer coefficients may be the only alternative. In this work the possibilities of enhancing impingement cooling by introducing surface enlarging - turbulence enhancing elements are examined experimentally. A configuration consisting of a staggered array of 45 impingement jets distributed over 10 rows is used for the purpose. A thermo camera is used to measure the temperature distribution on the target plate, giving an opportunity to separately evaluate the Nusselt number enhancement for different areas. Experiments are conducted for five different area enlarging geometries: triangle, wing, cylinder, dashed rib, and angel, all made from aluminium. Comparison between each area enlarged surface and a flat plate is made, with results presented as Nusselt number enhancement factors. The effect of pumping power required is also investigated in order to maximize the cooling efficiency. Parameters varied are Reynolds number and jet to plate distance. Overall Nusselt number enhancement factors show values of 1 to 1.3, the trend being decreasing with increased jet to plane distance and Reynolds number. When taking into account pumping power the enhancement factors drop to 0.4 to 1.2. The best results are achieved with the rib geometry and when not using a too large value of enlarger height over jet to plate distance (h/z). Row wise evaluation of Nusselt number enhancement shows an increased enhancement with row number and thereby crossflow ratio (Gc/Gj). Typical increases in enhancement of 1 to 1.5 with Gc/Gj from 0 to 0.8 are found. The thermo camera pictures reveal that the enhancement is found in three different areas, on the enlarger base area, the area just downstream the enlarger and in diagonal streaks with increased turbulence caused by the enlargers. Tests using an

Subependymal Heterotopia Mimicking Mass in Conventional Magnetic Resonance Imaging: Demonstration With 3T Advanced Neuroimages.

Science.gov (United States)

Aktas, Filiz; Ogul, Hayri

2017-10-01

The authors reported a rare patient with large subependymal heterotopia mimicking cerebral neoplasia. A 22-year-old female was admitted with a history of right-sided paresthesia accompanied by progressive headache. Cerebral magnetic resonance (MR) imaging showed a large solid lesion in the left frontal lobe. Advanced MR images proved that the lesion was compatible with subependymal heterotopia. Large subependymal heterotopia may mimick cerebral neoplasia.

Autoimmunity to Tropomyosin-Specific Peptides Induced by Mycobacterium leprae in Leprosy Patients: Identification of Mimicking Proteins.

Science.gov (United States)

Singh, Itu; Yadav, Asha Ram; Mohanty, Keshar Kunja; Katoch, Kiran; Sharma, Prashant; Pathak, Vinay Kumar; Bisht, Deepa; Gupta, Umesh D; Sengupta, Utpal

2018-01-01

It has been shown earlier that there is a rise in the levels of autoantibodies and T cell response to cytoskeletal proteins in leprosy. Our group recently demonstrated a rise in both T and B cell responses to keratin and myelin basic protein in all types of leprosy patients and their associations in type 1 reaction (T1R) group of leprosy. In this study, we investigated the association of levels of autoantibodies and lymphoproliferation against myosin in leprosy patients across the spectrum and tried to find out the mimicking proteins or epitopes between host protein and protein/s of Mycobacterium leprae . One hundred and sixty-nine leprosy patients and 55 healthy controls (HC) were enrolled in the present study. Levels of anti-myosin antibodies and T-cell responses against myosin were measured by ELISA and lymphoproliferation assay, respectively. Using 2-D gel electrophoresis, western blot and MALDI-TOF/TOF antibody-reactive spots were identified. Three-dimensional structure of mimicking proteins was modeled by online server. B cell epitopes of the proteins were predicted by BCPREDS server 1.0 followed by identification of mimicking epitopes. Mice of inbred BALB/c strain were hyperimmunized with M. leprae soluble antigen (MLSA) and splenocytes and lymph node cells of these animals were adoptively transferred to naïve mice. Highest level of anti-myosin antibodies was noted in sera of T1R leprosy patients. We observed significantly higher levels of lymphoproliferative response ( p  leprae . We found four mimicking epitopes between these sequences. These data suggest that these mimicking proteins tropomyosin and ATP-dependent Clp protease ATP-binding subunit of M. leprae or more precisely mimicking epitopes (four B cell epitopes) might be responsible for extensive tissue damage during type1 reaction in leprosy.

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

Friedreich's ataxia mimicking hereditary motor and sensory neuropathy.

Science.gov (United States)

Panas, Marios; Kalfakis, Nikolaos; Karadima, Georgia; Davaki, Panagiota; Vassilopoulos, Demetris

2002-11-01

Four patients from three unrelated families, with clinical and electrophysiological findings compatible with the diagnosis of hereditary motor and sensory neuropathy, are presented. The molecular analysis showed that the affected individuals were homozygous for the mutation in the X25 gene, characteristic of Friedreich's ataxia. These patients seem to represent a form of Friedreich's ataxia mimicking Charcot-Marie-Tooth disease.

Shoulder MR arthrography of the posterior labrocapsular complex in overhead throwers with pathologic internal impingement and internal rotation deficit

International Nuclear Information System (INIS)

Tuite, Michael J.; Petersen, Brian D.; Wise, Steven M.; Fine, Jason P.; Kaplan, Lee D.; Orwin, John F.

2007-01-01

To determine if overhead-throwing athletes with internal impingement pain and internal rotation deficit have thickening of the posterior inferior labrocapsular complex on MR arthrogram images. This study was approved and a waiver of consent granted by our institutional review board. Twenty-six overhead-throwing athletes with internal impingement pain and internal rotation deficit, and 26 controls who had undergone MR arthrograms, were retrospectively examined. The MR studies were combined and read in a blind fashion. On an axial image through the posteroinferior glenoid rim, the readers measured the labral length, capsule-labrum length, and the posterior recess angle. A t-test was used to determine statistical significance. The mean labral length was 4.9 mm [standard deviation (SD) 1.4 mm] for the controls, and 6.4 mm (SD 1.6 mm) for the athletes (P = 0.001). The mean capsule-labrum length was 5.4 mm (SD 2.1 mm) for the controls, and 8.8 mm (SD 2.9 mm) for the athletes (P < 0.001). The mean posterior recess angle measured 65 (SD 27 ) for the controls and 94 (SD 38 ) for the athletes (P = 0.002). Overhead-throwing athletes with internal impingement pain and internal rotation deficit tend to have a thicker labrum and a shallower capsular recess in the posterior inferior shoulder joint than do non-overhead-throwing athletes. In many, the posteroinferior capsule is also thickened. These MR findings should alert the radiologist to closely inspect the posterior cuff and posterosuperior labrum for the tears associated with internal impingement. (orig.)

Shoulder MR arthrography of the posterior labrocapsular complex in overhead throwers with pathologic internal impingement and internal rotation deficit

Energy Technology Data Exchange (ETDEWEB)

Tuite, Michael J; Petersen, Brian D; Wise, Steven M [University of Wisconsin Hospital and Clinics, Department of Radiology, Madison, WI (United States); Fine, Jason P [University of Wisconsin Hospital and Clinics, Department of Biostatistics, Madison, WI (United States); Kaplan, Lee D; Orwin, John F [University of Wisconsin Hospital and Clinics, Department of Orthopedic Surgery, Madison, WI (United States)

2007-06-15

To determine if overhead-throwing athletes with internal impingement pain and internal rotation deficit have thickening of the posterior inferior labrocapsular complex on MR arthrogram images. This study was approved and a waiver of consent granted by our institutional review board. Twenty-six overhead-throwing athletes with internal impingement pain and internal rotation deficit, and 26 controls who had undergone MR arthrograms, were retrospectively examined. The MR studies were combined and read in a blind fashion. On an axial image through the posteroinferior glenoid rim, the readers measured the labral length, capsule-labrum length, and the posterior recess angle. A t-test was used to determine statistical significance. The mean labral length was 4.9 mm [standard deviation (SD) 1.4 mm] for the controls, and 6.4 mm (SD 1.6 mm) for the athletes (P = 0.001). The mean capsule-labrum length was 5.4 mm (SD 2.1 mm) for the controls, and 8.8 mm (SD 2.9 mm) for the athletes (P < 0.001). The mean posterior recess angle measured 65 (SD 27 ) for the controls and 94 (SD 38 ) for the athletes (P = 0.002). Overhead-throwing athletes with internal impingement pain and internal rotation deficit tend to have a thicker labrum and a shallower capsular recess in the posterior inferior shoulder joint than do non-overhead-throwing athletes. In many, the posteroinferior capsule is also thickened. These MR findings should alert the radiologist to closely inspect the posterior cuff and posterosuperior labrum for the tears associated with internal impingement. (orig.)

Numerical investigation into the unsteady effects of non-axisymmetric turbine endwall contouring on secondary flows

CSIR Research Space (South Africa)

Dunn, Dwain I

2011-08-01

Full Text Available with the rotor leading edge, i.e. the location that the wake impinges on the leading edge of the rotor. It can be seen that there was not much fluctuation in time in the pressure profiles. With regards to the annular case the pressure surface shows... and lighter for a given b) (1) (A) (b) (1) (A) 2 thrust rating, the stronger secondary flows become. Therefore a reduction in secondary flow leads to an increase in performance of the turbine engine. One of the methods currently being investigated...

Autoimmunity to Tropomyosin-Specific Peptides Induced by Mycobacterium leprae in Leprosy Patients: Identification of Mimicking Proteins

Directory of Open Access Journals (Sweden)

Itu Singh

2018-04-01

Full Text Available BackgroundIt has been shown earlier that there is a rise in the levels of autoantibodies and T cell response to cytoskeletal proteins in leprosy. Our group recently demonstrated a rise in both T and B cell responses to keratin and myelin basic protein in all types of leprosy patients and their associations in type 1 reaction (T1R group of leprosy.ObjectivesIn this study, we investigated the association of levels of autoantibodies and lymphoproliferation against myosin in leprosy patients across the spectrum and tried to find out the mimicking proteins or epitopes between host protein and protein/s of Mycobacterium leprae.MethodologyOne hundred and sixty-nine leprosy patients and 55 healthy controls (HC were enrolled in the present study. Levels of anti-myosin antibodies and T-cell responses against myosin were measured by ELISA and lymphoproliferation assay, respectively. Using 2-D gel electrophoresis, western blot and MALDI-TOF/TOF antibody-reactive spots were identified. Three-dimensional structure of mimicking proteins was modeled by online server. B cell epitopes of the proteins were predicted by BCPREDS server 1.0 followed by identification of mimicking epitopes. Mice of inbred BALB/c strain were hyperimmunized with M. leprae soluble antigen (MLSA and splenocytes and lymph node cells of these animals were adoptively transferred to naïve mice.ResultsHighest level of anti-myosin antibodies was noted in sera of T1R leprosy patients. We observed significantly higher levels of lymphoproliferative response (p < 0.05 with myosin in all types of leprosy patients compared to HC. Further, hyperimmunization of inbred BALB/c strain of female mice and rabbit with MLSA revealed that both hyperimmunized rabbit and mice evoked heightened levels of antibodies against myosin and this autoimmune response could be adoptively transferred from hyperimmunized to naïve mice. Tropomyosin was found to be mimicking with ATP-dependent Clp protease ATP

Flow Patterns in an Open Channel Confluence with Increasingly Dominant Tributary Inflow

Directory of Open Access Journals (Sweden)

Laurent Schindfessel

2015-08-01

Full Text Available Despite the ratio of incoming discharges being recognized as a key parameter in open-channel confluence hydrodynamics, little is known about the flow patterns when the tributary provides more than 90% of the total discharge. This paper offers a systematic study of flow features when the tributary becomes increasingly dominant in a 90° confluence with a fixed concordant bed. Large-eddy simulations are used to investigate the three-dimensional complex flow patterns for three different discharge ratios. It is found that the tributary flow impinges on the opposing bank when the tributary flow becomes sufficiently dominant, causing a recirculating eddy in the upstream channel of the confluence, which induces significant changes in the incoming velocity distribution. Moreover, it results in stronger helicoidal cells in the downstream channel, along with zones of upwelling flow. In turn, the changed flow patterns also influence the mixing layer and the flow recovery. Finally, intermittent events of stronger upwelling flow are discerned. Improved understanding of flow patterns at confluences where the tributary is dominant is applicable to both engineering and earth sciences.

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.

Survey of fish impingement at power plants in the United States. Volume III. Estuaries and coastal waters

International Nuclear Information System (INIS)

Stupka, R.C.; Sharma, R.K.

1977-03-01

Impingement of fish at cooling-water intakes of 32 power plants, located on estuaries and coastal waters 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

Survey of fish impingement at power plants in the United States. Volume III. Estuaries and coastal waters

Energy Technology Data Exchange (ETDEWEB)

Stupka, Richard C.; Sharma, Rajendra K.

1977-03-01

Impingement of fish at cooling-water intakes of 32 power plants, located on estuaries and coastal waters 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.

Jet impinging onto a laser drilled tapered hole: Influence of tapper location on heat transfer and skin friction at hole surface

Science.gov (United States)

Shuja, S. Z.; Yilbas, B. S.

2013-02-01

Jet emerging from a conical nozzle and impinging onto a tapered hole in relation to laser drilling is investigated and the influence taper location on the heat transfer and skin friction at the hole wall surface is examined. The study is extended to include four different gases as working fluid. The Reynolds stress model is incorporated to account for the turbulence effect in the flow field. The hole wall surface temperature is kept at 1500 K to resemble the laser drilled hole. It is found that the location of tapering in the hole influences the heat transfer rates and skin friction at the hole wall surface. The maximum skin friction coefficient increases for taper location of 0.25 H, where H is the thickness of the workpiece, while Nusselt number is higher in the hole for taper location of 0.75 H.

Important clinical descriptors to include in the examination and assessment of patients with femoroacetabular impingement syndrome

DEFF Research Database (Denmark)

Reiman, M P; Thorborg, K; Covington, K

2017-01-01

PURPOSE: Determine which examination findings are key clinical descriptors of femoroacetabular impingement syndrome (FAIS) through use of an international, multi-disciplinary expert panel. METHODS: A three-round Delphi survey utilizing an international, multi-disciplinary expert panel operationally...

Study on flow phenomena at a mixing tee pipe in plants

International Nuclear Information System (INIS)

Maeda, Shogo; Kubota, Hiroki; Sugimoto, Katsumi; Takenaka, Nobuyuki; Miyoshi, Koji

2016-01-01

Thermal fatigue cracking may initiate at a tee pipe in plants where high and low temperature fluids flow in. The thermal stress fluctuation is caused by the wall temperature fluctuation due to heat transfer of the fluid temperature fluctuation near the wall. In order to elucidate the flow phenomena at a mixing tee pipe to cause temperature fluctuation, a visualization experiment of the flow in mixing section was conducted using a rectangular test section made of acrylic. As a result, the flow pattern was classified by momentum ratio M_R of the main and branch pipes, and it changed from wall jet to deflecting jet on M_R=3.70, and from deflecting jet to impinging jet on M_R=0.64. The jet flow from the branch pipe is swaying at a period of from about 5 s to 10 s. The relationship between the periods of fluctuation and M_R was investigated. The period decreased as M_R increased. (author)

Cam and Pincer Type of Femoroacetabular Impingement.

Science.gov (United States)

Ersoy, Hale; Trane, R Nicholas; Pomeranz, Stephen J

Femoroacetabular impingement (FAI) has gained considerable attention for the past 20 years and has been accepted as a predisposing factor for early osteoarthritis in young patients, particularly in the population participating in sports. Patients with FAI typically present with deep, intermittent groin discomfort during or after activities involving repetitive or persistent hip flexion. Symptomatic improvement can be achieved from arthroscopic debridement of unstable cartilage flaps, shaving of cartilage irregularities, and surgical correction of deformity of the femoral head\\endash neck junction. Early and correct diagnosis of FAI has paramount importance for appropriate and timely management of the disorder before the development of osteoarthritis. Magnetic resonance (MR) imaging offers a noninvasive means of assessing the degree of damage to cartilage and adjacent labrum and bone and also evaluating the effectiveness of treatment. This article describes the morphologic types of FAI with emphasis on MR findings.

Central skeletal sarcoidosis mimicking metastatic disease

International Nuclear Information System (INIS)

Talmi, Danit; Smith, Stacy; Mulligan, Michael E.

2008-01-01

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.)

Film cooling air pocket in a closed loop cooled airfoil

Science.gov (United States)

Yu, Yufeng Phillip; Itzel, Gary Michael; Osgood, Sarah Jane; Bagepalli, Radhakrishna; Webbon, Waylon Willard; Burdgick, Steven Sebastian

2002-01-01

Turbine stator vane segments have radially inner and outer walls with vanes extending between them. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. To provide for air film cooing of select portions of the airfoil outer surface, at least one air pocket is defined on a wall of at least one of the cavities. Each air pocket is substantially closed with respect to the cooling medium in the cavity and cooling air pumped to the air pocket flows through outlet apertures in the wall of the airfoil to cool the same.

Film cooling for a closed loop cooled airfoil

Science.gov (United States)

Burdgick, Steven Sebastian; Yu, Yufeng Phillip; Itzel, Gary Michael

2003-01-01

Turbine stator vane segments have radially inner and outer walls with vanes extending therebetween. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. At least one film cooling hole is defined through a wall of at least one of the cavities for flow communication between an interior of the cavity and an exterior of the vane. The film cooling hole(s) are defined adjacent a potential low LCF life region, so that cooling medium that bleeds out through the film cooling hole(s) reduces a thermal gradient in a vicinity thereof, thereby the increase the LCF life of that region.

Evaluation of tomosynthesis elastography in a breast-mimicking phantom

International Nuclear Information System (INIS)

Engelken, Florian Jan; Sack, Ingolf; Klatt, Dieter; Fischer, Thomas; Fallenberg, Eva Maria; Bick, Ulrich; Diekmann, Felix

2012-01-01

Objective: To evaluate whether measurement of strain under static compression in tomosynthesis of a breast-mimicking phantom can be used to distinguish tumor-simulating lesions of different elasticities and to compare the results to values predicted by rheometric analysis as well as results of ultrasound elastography. Materials and methods: We prepared three soft breast-mimicking phantoms containing simulated tumors of different elasticities. The phantoms were imaged using a wide angle tomosynthesis system with increasing compression settings ranging from 0 N to 105 N in steps of 15 N. Strain of the inclusions was measured in two planes using a commercially available mammography workstation. The elasticity of the phantom matrix and inclusion material was determined by rheometric analysis. Ultrasound elastography of the inclusions was performed using two different ultrasound elastography algorithms. Results: Strain at maximal compression was 24.4%/24.5% in plane 1/plane 2, respectively, for the soft inclusion, 19.6%/16.9% for the intermediate inclusion, and 6.0%/10.2% for the firm inclusion. The strain ratios predicted by rheometrical testing were 0.41, 0.83 and 1.26 for the soft, intermediate, and firm inclusions, respectively. The strain ratios obtained for the soft, intermediate, and firm inclusions were 0.72 ± 0.13, 1.02 ± 0.21 and 2.67 ± 1.70, respectively for tomosynthesis elastography, 0.91, 1.64 and 2.07, respectively, for ultrasound tissue strain imaging, and 0.97, 2.06 and 2.37, respectively, for ultrasound real-time elastography. Conclusions: Differentiation of tumor-simulating inclusions by elasticity in a breast mimicking phantom may be possible by measuring strain in tomosynthesis. This method may be useful for assessing elasticity of breast lesions tomosynthesis of the breast

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.)

Spinal MRI of vincristine neuropathy mimicking Guillain-Barre syndrome

International Nuclear Information System (INIS)

Chang, Yun Woo; Yoon, Hye-Kyung; Cho, Jae Min; Sung, Ki Woong

2003-01-01

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.)

Primary intraosseous squamous cell carcinoma mimicking periapical disease: a case report

Energy Technology Data Exchange (ETDEWEB)

Choi, Yoon Joo; Oh, Song Hee; Kang, Ju Han; Choi, Hwa Young; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of); Yu, Jae June [Dept. of Oral and Maxillofacial Radiology, Kangdong Sacred Heart Hospital, Hallym Medical Center, Seoul (Korea, Republic of)

2012-09-15

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare carcinoma, which arises within the jaws without connection to the oral mucosa and presumably develops from a remnant of odontogenic epithelium. We present a case of solid type PIOSCC in a 52-year-old male patient complaining of dull pain on his left lower molar. In this case, early stage PIOSCC mimicking a periapical lesion might lead to a one-year delay in treatment due to the misdiagnosis of osteomyelitis after extraction of the third molar. The clinical, radiological, and histologic features are described. In this case, there was initial radiographic evidence for PIOSCC mimicking a periapical lesion. Incautious radiographic interpretation and treatment procedures had delayed the correct diagnosis and resulted in extensive bony destruction during the patient's disease progression.

Numerical modelling of heat transfer in a cavity due to liquid jet impingement for liquid supported stretch blow moulding

Science.gov (United States)

Smyth, Trevor; Menary, Gary; Geron, Marco

2018-05-01

Impingement of a liquid jet in a polymer cavity has been modelled numerically in this study. Liquid supported stretch blow moulding is a nascent polymer forming process using liquid as the forming medium to produce plastic bottles. The process derives from the conventional stretch blow moulding process which uses compressed air to deform the preform. Heat transfer away from the preform greatly increases when a liquid instead of a gas is flowing over a solid; in the blow moulding process the temperature of the preform is tightly controlled to achieve optimum forming conditions. A model was developed with Computational Fluid Dynamics code ANSYS Fluent which allows the extent of heat transfer between the incoming liquid and the solid preform to be determined in the initial transient stage, where a liquid jet enters an air filled preform. With this data, an approximation of the extent of cooling through the preform wall can be determined.

Adefovir-Induced Hypophosphatemic Osteomalacia Mimicking Bone Metastases From Primary Hepatocarcinoma.

Science.gov (United States)

Wei, Wei-Jun; Sun, Zhen-Kui; Shen, Chen-Tian; Qiu, Zhong-Ling; Luo, Quan-Yong

2017-09-01

Adefovir-induced hypophosphatemic osteomalacia in the context of hepatocarcinoma is rare and needs to be differentiated from metastatic hepatocarcinoma. We here report a case of severe osteomalacia whose focal uptakes of radiotracer on the Tc-MDP SPECT/CT images mimicked that of metastatic hepatocarcinoma.

Bilateral iliopsoas muscle contracture and spinous process impingement in a German Shepherd dog.

Science.gov (United States)

Ragetly, Guillaume R; Griffon, Dominique J; Johnson, Ann L; Blevins, William E; Valli, Victor E

2009-12-01

To report diagnosis and treatment of bilateral iliopsoas muscle contracture in a dog with spinous process impingement. Case report. German Shepherd dog. A dog with chronic progressive lameness, flexion contracture of the coxofemoral joints, severe pain, and decreased femoral reflexes had severe spondylosis bridging the vertebral bodies from L1 to L4 and enlarged dorsal spinous processes from T8 to L6 with impingement and bony proliferation. Ultrasonographic and magnetic resonance imaging (MRI) findings were consistent with fibrosis, mineralization, and atrophy of the iliopsoas muscles bilaterally which was treated by staged tenectomy of the insertions of the iliopsoas muscles. Because of severe perivascular fibrosis, the femoral vessels required ligation. Bilateral iliopsoas muscle tenectomy improved gait and provided pain relief. Histologic findings were consistent with fibrotic myopathy. Slow progression of severe clinical signs observed bilaterally in this dog differs from previous reports of iliopsoas myopathy. Findings were similar to the fibrotic myopathy of the gracilis or semitendinosus muscles described in dogs. Iliopsoas muscle abnormalities should be considered in dogs with limited hip extension and pain. MRI is useful for diagnosing muscle fibrosis. Iliopsoas tenectomy may improve clinical function in dogs with fibrotic myopathy.

Mucosal deformation from an impinging transonic gas jet and the ballistic impact of microparticles

International Nuclear Information System (INIS)

Hardy, M P; Kendall, M A F

2005-01-01

By means of a transonic gas jet, gene guns ballistically deliver microparticle formulations of drugs and vaccines to the outer layers of the skin or mucosal tissue to induce unique physiological responses for the treatment of a range of conditions. Reported high-speed imaging experiments show that the mucosa deforms significantly while subjected to an impinging gas jet from a biolistic device. In this paper, the effect of this tissue surface deformation on microparticle impact conditions is simulated with computational fluid dynamics (CFD) calculations. The microparticles are idealized as spheres of diameters 26.1, 39 and 99 μm and a density of 1050 kg m -3 . Deforming surface calculations of particle impact conditions are compared directly with an immobile surface case. The relative velocity and obliquity of the deforming surface decrease the normal component of particle impact velocity by up to 30% at the outer edge of the impinging gas jet. This is qualitatively consistent with reported particle penetration profiles in the tissue. It is recommended that these effects be considered in biolistic studies requiring quantified particle impact conditions

SU-F-T-433: Evaluation of a New Dose Mimicking Application for Clinical Flexibility and Reliability

International Nuclear Information System (INIS)

Hoffman, D; Nair, C Kumaran; Wright, C; Yamamoto, T; Mayadev, J; Valicenti, R; Benedict, S; Rong, Y; Markham, J

2016-01-01

Purpose: Clinical workflow and machine down time occasionally require patients to be temporarily treated on a system other than the initial treatment machine. A new commercial dose mimicking application provides automated cross-platform treatment planning to expedite this clinical flexibility. The aim of this work is to evaluate the feasibility of automatic plan creation and establish a robust clinical workflow for prostate and pelvis patients. Methods: Five prostate and five pelvis patients treated with helical plans were selected for re-planning with the dose mimicking application, covering both simple and complex scenarios. Two-arc VMAT and 7- and 9-field IMRT plans were generated for each case, with the objective function of achieving similar dose volume histogram from the initial helical plans. Dosimetric comparisons include target volumes and organs at risk (OARs) (rectum, bladder, small bowel, femoral heads, etc.). Dose mimicked plans were evaluated by a radiation oncologist, and patient-specific QAs were performed to validate delivery. Results: Overall plan generation and transfer required around 30 minutes of dosimetrist’s time once the dose-mimicking protocol is setup for each site. The resulting VMAT and 7- and 9-field IMRT plans achieved equivalent PTV coverage and homogeneity (D99/DRx = 97.3%, 97.2%, 97.2% and HI = 6.0, 5.8, and 5.9, respectively), compared to helical plans (97.6% and 4.6). The OAR dose discrepancies were up to 6% in rectum Dmean, but generally lower in bladder, femoral heads, bowel and penile bulb. In the context of 1–5 fractions, the radiation oncologist evaluated the dosimetric changes as not clinically significant. All delivery QAs achieved >90% pass with a 3%/3mm gamma criteria. Conclusion: The automated dose-mimicking workflow offers a strategy to avoid missing treatment fractions due to machine down time with non-clinically significant changes in dosimetry. Future work will further optimize dose mimicking plans and

SU-F-T-433: Evaluation of a New Dose Mimicking Application for Clinical Flexibility and Reliability

Energy Technology Data Exchange (ETDEWEB)

Hoffman, D; Nair, C Kumaran; Wright, C; Yamamoto, T; Mayadev, J; Valicenti, R; Benedict, S; Rong, Y [University of California Davis Medical Center, Sacramento, CA (United States); Markham, J [Raysearch Laboratories, Garden City, NY (United States)

2016-06-15

Purpose: Clinical workflow and machine down time occasionally require patients to be temporarily treated on a system other than the initial treatment machine. A new commercial dose mimicking application provides automated cross-platform treatment planning to expedite this clinical flexibility. The aim of this work is to evaluate the feasibility of automatic plan creation and establish a robust clinical workflow for prostate and pelvis patients. Methods: Five prostate and five pelvis patients treated with helical plans were selected for re-planning with the dose mimicking application, covering both simple and complex scenarios. Two-arc VMAT and 7- and 9-field IMRT plans were generated for each case, with the objective function of achieving similar dose volume histogram from the initial helical plans. Dosimetric comparisons include target volumes and organs at risk (OARs) (rectum, bladder, small bowel, femoral heads, etc.). Dose mimicked plans were evaluated by a radiation oncologist, and patient-specific QAs were performed to validate delivery. Results: Overall plan generation and transfer required around 30 minutes of dosimetrist’s time once the dose-mimicking protocol is setup for each site. The resulting VMAT and 7- and 9-field IMRT plans achieved equivalent PTV coverage and homogeneity (D99/DRx = 97.3%, 97.2%, 97.2% and HI = 6.0, 5.8, and 5.9, respectively), compared to helical plans (97.6% and 4.6). The OAR dose discrepancies were up to 6% in rectum Dmean, but generally lower in bladder, femoral heads, bowel and penile bulb. In the context of 1–5 fractions, the radiation oncologist evaluated the dosimetric changes as not clinically significant. All delivery QAs achieved >90% pass with a 3%/3mm gamma criteria. Conclusion: The automated dose-mimicking workflow offers a strategy to avoid missing treatment fractions due to machine down time with non-clinically significant changes in dosimetry. Future work will further optimize dose mimicking plans and

An abdominal tuberculosis case mimicking an abdominal mass

African Journals Online (AJOL)

An abdominal tuberculosis case mimicking an abdominal mass. Derya Erdog˘ an a. , Yasemin Ta ¸scı Yıldız b. , Esin Cengiz Bodurog˘lu c and Naciye Go¨nu¨l Tanır d. Abdominal tuberculosis is rare in childhood. It may be difficult to diagnose as it mimics various disorders. We present a 12-year-old child with an unusual ...

Characterization of ossification of the posterior rim of acetabulum in the developing hip and its impact on the assessment of femoroacetabular impingement.

Science.gov (United States)

Morris, William Z; Chen, Jason Y; Cooperman, Daniel R; Liu, Raymond W

2015-02-04

Many radiographic indices that are used to assess adolescents for femoroacetabular impingement rely on an ossified posterior acetabular wall. A recent study identified a secondary ossification center in the posterior rim of the acetabulum, the ossification of which may affect perceived acetabular coverage. The purpose of this study was to characterize ossification of the posterior rim of the acetabulum with use of a longitudinal radiographic study and quantify its impact on the radiographic assessment of femoroacetabular impingement. In this study, we utilized a historical collection of annual radiographs made in a population of healthy adolescents. Six hundred and twelve anteroposterior radiographs of the left hip of ninety-eight patients were reviewed to identify the appearance, duration, and fusion of the secondary ossification center in the posterior rim of the acetabulum. The center-edge angle was then measured before appearance and after fusion of the secondary ossification center in a subset of ten patients who had 40°), the use of radiographs in adolescents with incompletely ossified hips may lead to misinterpretation of acetabular coverage. In patients with open triradiate cartilage, magnetic resonance imaging may be considered for the assessment of femoroacetabular impingement. The posterior rim ossification sign is a normal finding in adolescent hip development and has important implications for the proper evaluation of femoroacetabular impingement. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Anomalous Power Flow and ``Ghost'' Sources

Science.gov (United States)

Monzon, Cesar

2008-08-01

It is demonstrated that EM radiation from complex sources can result in real power in restricted regions of space flowing back towards the sources, thereby mimicking “ghost” sources. This counterintuitive mechanism of radiation does not rely on backward waves, as ordinary waves carry the power. Ways to harness the effect by making it directional are presented, together with selected applications, of which deception is a prime example due to the nature of the phenomenon. The concept can be applied to other areas, such as mechanics, acoustics, etc., and can be realized with available technology.

The activity pattern of shoulder muscles in subjects with and without subacromial impingement

DEFF Research Database (Denmark)

Diederichsen, Louise Pyndt; Nørregaard, Jesper; Dyhre-Poulsen, Poul

2009-01-01

Altered shoulder muscle activity is frequently believed to be a pathogenetic factor of subacromial impingement (SI) and therapeutic interventions have been directed towards restoring normal motor patterns. Still, there is a lack of scientific evidence regarding the changes in muscle activity in p...... that the different motor patterns might be a pathogenetic factor of SI, perhaps due to inappropriate neuromuscular strategies affecting both shoulders....

Risk of surgery for subacromial impingement syndrome in relation to neck-shoulder complaints and occupational biomechanical exposures

DEFF Research Database (Denmark)

Svendsen, Susanne Wulff; Dalbøge, Annett; Andersen, JH

2013-01-01

OBJECTIVES: The aim of this longitudinal study was to evaluate the risk of surgery for subacromial impingement syndrome (SIS) in relation to neck-shoulder complaints and occupational biomechanical shoulder exposures. METHODS: The study was based on the Musculoskeletal Research Database at the Dan......OBJECTIVES: The aim of this longitudinal study was to evaluate the risk of surgery for subacromial impingement syndrome (SIS) in relation to neck-shoulder complaints and occupational biomechanical shoulder exposures. METHODS: The study was based on the Musculoskeletal Research Database....... Using no neck-shoulder complaints and low shoulder load at baseline as a reference, no neck-shoulder complaints and high shoulder load showed an adjusted hazard ratio (HR adj) of 2.55 [95% confidence interval (95% CI) 1.59-4.09], while neck-shoulder complaints in combination with high shoulder load...

Neoplastic stomach lesions and their mimickers: spectrum of imaging manifestations

OpenAIRE

Virmani, Vivek; Khandelwal, Ashish; Sethi, Vineeta; Fraser-Hill, Margret; Fasih, Najla; Kielar, Ania

2012-01-01

Abstract This review illustrates a wide spectrum of gastric neoplasms with emphasis on imaging findings helpful in characterizing various gastric neoplasms. Both the malignant and benign neoplasms along with focal gastric masses mimicking tumour are illustrated. Moreover, imaging clues to reach an accurate diagnosis are emphasized.

Mimicking expressiveness of movements by autistic children in game play

NARCIS (Netherlands)

Tetteroo, D.; Shirzad, A.; Serras Pereira, M.; Zwinderman, M.J.; Duy, L.; Barakova, E.I.

2012-01-01

Children with Autistic Spectrum Disorder (ASD)have marked impairments in social interaction. Imitation is a basic social interaction behavior, and mimicking as an element of imitation can be a diagnostic marker for autism and thus a skill that can be targeted by behavioral training. In a comparative

Heparin-mimicking multilayer coating on polymeric membrane via LbL assembly of cyclodextrin-based supramolecules.

Science.gov (United States)

Deng, Jie; Liu, Xinyue; Ma, Lang; Cheng, Chong; Shi, Wenbin; Nie, Chuanxiong; Zhao, Changsheng

2014-12-10

In this study, multifunctional and heparin-mimicking star-shaped supramolecules-deposited 3D porous multilayer films with improved biocompatibility were fabricated via a layer-by-layer (LbL) self-assembly method on polymeric membrane substrates. Star-shaped heparin-mimicking polyanions (including poly(styrenesulfonate-co-sodium acrylate; Star-PSS-AANa) and poly(styrenesulfonate-co-poly(ethylene glycol)methyl ether methacrylate; Star-PSS-EGMA)) and polycations (poly(methyl chloride-quaternized 2-(dimethylamino)ethyl methacrylate; Star-PMeDMA) were first synthesized by atom transfer radical polymerization (ATRP) from β-cyclodextrin (β-CD) based cores. Then assembly of 3D porous multilayers onto polymeric membrane surfaces was carried out by alternating deposition of the polyanions and polycations via electrostatic interaction. The surface morphology and composition, water contact angle, blood activation, and thrombotic potential as well as cell viability for the coated heparin-mimicking films were systematically investigated. The results of surface ATR-FTIR spectra and XPS spectra verified successful deposition of the star-shaped supramolecules onto the biomedical membrane surfaces; scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations revealed that the modified substrate had 3D porous surface morphology, which might have a great biological influence on the biointerface. Furthermore, systematic in vitro investigation of protein adsorption, platelet adhesion, human platelet factor 4 (PF4, indicates platelet activation), activate partial thromboplastin time (APTT), thrombin time (TT), coagulation activation (thrombin-antithrombin III complex (TAT, indicates blood coagulant)), and blood-related complement activation (C3a and C5a, indicates inflammation potential) confirmed that the heparin-mimicking multilayer coated membranes exhibited ultralow blood component activations and excellent hemocompatibility. Meanwhile, after surface coating

Arterial pseudoaneurysms of the shoulder mimicking other entities: utilization of pulsation artifact on musculoskeletal MR for accurate diagnosis in 2 cases

Energy Technology Data Exchange (ETDEWEB)

Samim, Mohammad [New York University, Department of Radiology, Hospital for Joint Disease, New York, NY (United States); Mandell, Jacob; Smith, Stacy; Kapoor, Neena; Czuczman, Gregory [Harvard Medical School, Department of Radiology, Brigham and Women' s Hospital, Boston, MA (United States)

2017-08-15

We present two cases of pseudoaneurysm (PSA) about the shoulder mimicking more common clinical entities - soft tissue neoplasm and septic arthritis - for which biopsy of the mass and joint aspiration were requested respectively. We review the imaging findings of PSA with emphasis on findings in musculoskeletal protocol MRI, including the identification of pulsation artifact in both cases, which was critical to establishing the correct diagnosis. In the proper clinical setting, with imaging findings demonstrating a complex mass or fluid collection, MR images should be scrutinized for the presence of pulsation artifact, which can help diagnose a high-flow vascular lesion and avoid a potentially harmful invasive procedure such as biopsy. (orig.)

Tratamento artroscópico do impacto femoroacetabular Arthroscopic treatment of femoroacetabular impingement

Directory of Open Access Journals (Sweden)

Giancarlo C. Polesello

2009-06-01

Full Text Available OBJETIVOS: O propósito deste estudo é avaliar os resultados em curto prazo do tratamento artroscópico do impacto femoroacetabular. A hipótese é a de que os resultados do tratamento artroscópico são favoráveis. MÉTODOS: Entre agosto de 2003 e agosto de 2007, 28 quadris foram submetidos ao tratamento do impacto femoroacetabular pela via artroscópica. A idade média dos pacientes foi de 34 anos, com média de seguimento de 27 meses. Quanto à melhora clínica, os pacientes foram avaliados pré e pósoperatoriamente pelo Harris Hip Score (HHS modificado por Byrd. Os pacientes foram avaliados pré e pós-operatoriamente em relação à rotação interna do quadril acometido. Os valores obtidos nos índices acima foram analisados estatisticamente através do método de Wilcoxon para a avaliação de variáveis não paramétricas. RESULTADOS: O Harris Hip Score médio pré-operatório foi de 54,2 e o pós-operatório, de 94,8 (p OBJECTIVE: The purpose of this study is to evaluate the short-term follow-up results of arthroscopic treatment of femoroacetabular impingement. Our hypothesis is that arthroscopic treatment results are favorable. METHODS: Between August 2003 and August 2007, 28 hips had femoroacetabular impingement treated by hip arthroscopy. The mean age was 34 years, with mean follow-up period of 27 months. Clinical results were graded with the modified Harris hip score, which was measured pre-and postoperatively. Patients had also their internal rotation analyzed. These parameters were calculated by using Wilcoxon's t test for analysis of nonparametric paired samples performed. RESULTS: The mean preoperative Harris Hip Score was 54.2, improving to 94.8 postoperatively (p<0,001. The mean increase was 37.5 points. We had 4 good results (15% and 24 excellent results (85%. Preoperatively, the patients had a mean internal rotation of 17º, and, postoperatively, 36º. The average internal rotation increase was 19º (p<0,001. CONCLUSIONS

Fibromatosis of the breast mimicking an abscess: case report of unusual sonographic features.

Science.gov (United States)

Lee, So Min; Lee, Ji Young; Lee, Byung Hoon; Kim, Su Young; Joo, Mee; Kim, Jae Il

2015-01-01

Fibromatosis of the breast, also known as a desmoid tumor, is extremely rare and most often appears as an aggressive lesion mimicking breast carcinoma. It lacks metastatic potential but can grow aggressively in a localized area. Ultrasonography often shows an irregular spiculated hypoechoic mass with posterior acoustic shadowing. We discuss a case of breast fibromatosis that presented as a painful palpable breast mass in a 32-year-old woman and mimicked an abscess in the sonogram. We found that this lesion displayed atypical sonographic features such as a heterogeneous echoic mass with an internal anechoic area. Copyright © 2015 Elsevier Inc. All rights reserved.

Primary Benign Intraosseous Meningioma on {sup 18}F-FDG PET/CT Mimicking Malignancy

Energy Technology Data Exchange (ETDEWEB)

Kim, Ho Seong; Kim, Seok Hwi; Kim, Hyung Jin; Kang, Se Woong; Kim, Soo Jeong; Lee, Joo Hee; Hong, Sun Pyo; Cho, Young Seok; Choi, Joon Young [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

2014-06-15

We present a case of primary benign intraosseous meningioma in the sphenoid bone mimicking malignancy. A 44-year-old female patient who had a protruding right eye and headache came to our hospital. MRI showed a large, destructive, heterogeneously well-enhancing soft tissue mass in the right sphenoid bone suggesting malignancy. {sup 18}F-FDG PET/CT showed a hypermetabolic mass in the same site with an SUV{sub max} of 9.1 The pathological diagnosis by surgery revealed that this tumor was a WHO grade I transitional meningioma. This case suggests that primary benign intraosseous meningioma may show high {sup 18}F-FDG uptake mimicking a malignancy.

Influence of plasma-generated negative oxygen ion impingement on magnetron sputtered amorphous SiO2 thin films during growth at low temperatures

International Nuclear Information System (INIS)

Macias-Montero, M.; Garcia-Garcia, F. J.; Alvarez, R.; Gil-Rostra, J.; Gonzalez, J. C.; Gonzalez-Elipe, A. R.; Palmero, A.; Cotrino, J.

2012-01-01

Growth of amorphous SiO 2 thin films deposited by reactive magnetron sputtering at low temperatures has been studied under different oxygen partial pressure conditions. Film microstructures varied from coalescent vertical column-like to homogeneous compact microstructures, possessing all similar refractive indexes. A discussion on the process responsible for the different microstructures is carried out focusing on the influence of (i) the surface shadowing mechanism, (ii) the positive ion impingement on the film, and (iii) the negative ion impingement. We conclude that only the trend followed by the latter and, in particular, the impingement of O - ions with kinetic energies between 20 and 200 eV, agrees with the resulting microstructural changes. Overall, it is also demonstrated that there are two main microstructuring regimes in the growth of amorphous SiO 2 thin films by magnetron sputtering at low temperatures, controlled by the amount of O 2 in the deposition reactor, which stem from the competition between surface shadowing and ion-induced adatom surface mobility.

Rotor boundary layer development with inlet guide vane (IGV) wake impingement

Science.gov (United States)

Jia, Lichao; Zou, Tengda; Zhu, Yiding; Lee, Cunbiao

2018-04-01

This paper examines the transition process in a boundary layer on a rotor blade under the impingement of an inlet guide vane wake. The effects of wake strengths and the reduced frequency on the unsteady boundary layer development on a low-speed axial compressor were investigated using particle image velocimetry. The measurements were carried out at two reduced frequencies (fr = fIGVS0/U2i, fr = 1.35, and fr = 0.675) with the Reynolds number, based on the blade chord and the isentropic inlet velocity, being 97 500. At fr = 1.35, the flow separated at the trailing edge when the wake strength was weak. However, the separation was almost totally suppressed as the wake strength increased. For the stronger wake, both the wake's high turbulence and the negative jet behavior of the wake dominated the interaction between the unsteady wake and the separated boundary layer on the suction surface of the airfoil. The boundary layer displacement thickened first due to the negative jet effect. Then, as the disturbances developed underneath the wake, the boundary layer thickness reduced gradually. The high disturbance region convected downstream at a fraction of the free-stream velocity and spread in the streamwise direction. The separation on the suction surface was suppressed until the next wake's arrival. Because of the long recovery time at fr = 0.675, the boundary layer thickened gradually as the wake convected further downstream and finally separated due to the adverse pressure gradient. The different boundary layer states in turn affected the development of disturbances.

Subdural Hematoma Mimickers: A Systematic Review.

Science.gov (United States)

Catana, Dragos; Koziarz, Alex; Cenic, Aleksa; Nath, Siddharth; Singh, Sheila; Almenawer, Saleh A; Kachur, Edward

2016-09-01

A variety of subdural pathologies that may mimic hematomas are reported in the literature. We aimed to identify the atypical clinical and radiologic presentations of subdural masses that may mimic subdural hematomas. A systematic review of MEDLINE and Embase was conducted independently by 2 reviewers to identify articles describing subdural hematoma mimickers. We also present a patient from our institution with a subdural pathology mimicking a subdural hematoma. We analyzed patient clinical presentations, underlying pathologies, radiologic findings, and clinical outcomes. We included 43 articles totaling 48 patients. The mean ± SD patient age was 55.7 ± 16.8 years. Of the 45 cases describing patient history, 13 patients (27%) had a history of trauma. The underlying pathologies of the 48 subdural collections were 10 metastasis (21%), 14 lymphoma (29%), 7 sarcoma (15%), 4 infectious (8%), 4 autoimmune (8%), and 9 miscellaneous (19%). Findings on computed tomography (CT) scan were 18 hyperdense (41%), 11 hypodense (25%), 9 isodense (20%), 3 isodense/hyperdense (7%), and 3 hypodense/isodense (7%). Thirty-four patients (71%) were treated surgically; among these patients, 65% had symptom resolution. Neither the pathology (P = 0.337) nor the management strategy (P = 0.671) was correlated with improved functional outcomes. Identification of atypical history and radiologic features should prompt further diagnostic tests, including magnetic resonance imaging (MRI), to elucidate the proper diagnosis, given that certain pathologies may be managed nonsurgically. A subdural collection that is hyperdense on CT scan and hyperintense on T2-weighted MRI, along with a history of progressive headache with no trauma, may raise the suspicion of an atypical subdural pathology. Copyright © 2016 Elsevier Inc. All rights reserved.

Primary Papillary Mucinous Adenocarcinoma of the Ureter Mimicking Genitourinary Tuberculosis

Science.gov (United States)

Gulwani, Hanni; Jain, Aruna

2010-01-01

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. PMID:21151719

Estimation of urinary flow velocity in models of obstructed and unobstructed urethras by decorrelation of ultrasound radiofrequency signals

NARCIS (Netherlands)

Arif, M.; Idzenga, T.; Mastrigt, R. van; Korte, C.L. de

2014-01-01

The feasibility of estimating urinary flow velocity from the decorrelation of radiofrequency (RF) signals was investigated in soft tissue-mimicking models of obstructed and unobstructed urethras. The decorrelation was studied in the near field, focal zone and far field of the ultrasound beam.

Can hip impingement be mistaken for tendon pain in the groin? A long-term follow-up of tenotomy for groin pain in athletes.

Science.gov (United States)

Sansone, Mikael; Ahldén, Mattias; Jonasson, Pall; Thomeé, Roland; Falk, Anders; Swärd, Leif; Karlsson, Jón

2014-04-01

There are several reports on the association between pubalgia and intra-articular hip disorders. The purpose of this study was to evaluate the long-term outcome in athletes who underwent tenotomy due to long-standing groin pain. A secondary purpose was evaluating the frequency of femoro-acetabular impingement (FAI) and its impact on the long-term outcome. Thirty-two high-level male athletes treated with adductor tenotomy, rectus abdominis tenotomy or both were included. At a median follow-up time of 6 years after the tenotomy, the subjects underwent standardised clinical examination, plain radiographs, completed web-based health-related patient-reported outcomes, including iHOT12, HAGOS (six subscales), EQ-5D (two subscales), HSAS for physical activity level and a VAS for overall hip function. Furthermore, patient satisfaction and return to sports were documented. Twenty-four of the 32 (75 %) athletes were satisfied with the outcome of the tenotomy, and 22 of the athletes (69 %) were able to return to their pre-injury sport. Before the long-term follow-up, two of these satisfied athletes had undergone repeat surgery (one hip arthroscopy due to FAI and one repeat tenotomy). Of the 24 satisfied athletes, eight (33 %) had a positive hip impingement test at the follow-up. Of the remaining eight athletes not satisfied with the outcome, only one returned to their pre-injury sport and three had undergone hip arthroscopy prior to follow-up. Five had positive hip impingement tests which was significantly more frequently than in the satisfied group (p = 0.008). The group with a positive hip impingement test reported significantly more pain and symptoms, more hip problems during sports and physical activity, as well as lower hip-related quality of life according to the HAGOS scores (p pubalgia yielded a satisfactory long-term outcome, with three of four athletes being able to return to their pre-injury sport. The athletes that did not return to their pre-injury sport had

Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies: A systematic review.

Science.gov (United States)

Mayne, E; Memarzadeh, A; Raut, P; Arora, A; Khanduja, V

2017-01-01

The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field. The Cochrane and PubMed libraries were searched for any publications using the terms 'hip', 'muscle', 'strength', and 'measurement' in the 'Title, Abstract, Keywords' field. A further search was performed using the terms 'femoroacetabular' or 'impingement'. The search was limited to recent literature only. A total of 29 articles were reviewed to obtain information on a number of variables. These comprised the type of device used for measurement, rater standardisation, the type of movements tested, body positioning and comparative studies of muscle strength in FAI versus normal controls. The studies found that hip muscle strength is lower in patients with FAI; this is also true for the asymptomatic hip in patients with FAI. Current literature on this subject is limited and examines multiple variables. Our recommendations for achieving reproducible results include stabilising the patient, measuring isometric movements and maximising standardisation by using a single tester and familiarising the participants with the protocol. Further work must be done to demonstrate the reliability of any new testing method.Cite this article: E. Mayne, A. Memarzadeh, P. Raut, A. Arora, V. Khanduja. Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies: A systematic review. Bone Joint Res 2017;6:66-72. DOI: 10.1302/2046-3758.61.BJR-2016-0081. © 2017 Khanduja et al.

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.

Cogan's syndrome mimicking acute Lyme arthritis.

Science.gov (United States)

Schwegmann, J P; Enzenauer, R J

1995-05-01

A pediatric case of Cogan's syndrome mimicking acute Lyme arthritis is described. A 12-year-old black boy was admitted to the pediatric service for presumed right knee septic arthritis. Symptoms included acute pain and swelling with decreased range-of-motion. Although the patient's right knee symptoms and positive Lyme serology were consistent with a diagnosis of Lyme arthritis, the presence of sensorineural hearing loss and interstitial keratitis with inflammatory arthritis suggested a diagnosis of Cogan's syndrome. Subsequent Western blot analysis was negative for Borrelia burgdorferi antigens. The patient had dramatic clinical improvement of musculoskeletal and ophthalmologic complaints shortly after receiving high-dose corticosteroids, although residual sensorineural hearing loss persisted.

NASA Langley Low Speed Aeroacoustic Wind Tunnel: Background Noise and Flow Survey Results Prior to FY05 Construction of Facilities Modifications

Science.gov (United States)

Booth, Earl R., Jr.; Henderson, Brenda S.

2005-01-01

The NASA Langley Research Center Low Speed Aeroacoustic Wind Tunnel is a premier facility for model-scale testing of jet noise reduction concepts at realistic flow conditions. However, flow inside the open jet test section is less than optimum. A Construction of Facilities project, scheduled for FY 05, will replace the flow collector with a new design intended to reduce recirculation in the open jet test section. The reduction of recirculation will reduce background noise levels measured by a microphone array impinged by the recirculation flow and will improve flow characteristics in the open jet tunnel flow. In order to assess the degree to which this modification is successful, background noise levels and tunnel flow are documented, in order to establish a baseline, in this report.

Remote Cutaneous Breast Carcinoma Metastasis Mimicking Dermatitis

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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.

Being Mimicked Increases Prosocial Behavior in 18-Month-Old Infants

Science.gov (United States)

Carpenter, Malinda; Uebel, Johanna; Tomasello, Michael

2013-01-01

Most previous research on imitation in infancy has focused on infants' learning of instrumental actions on objects. This study focused instead on the more social side of imitation, testing whether being mimicked increases prosocial behavior in infants, as it does in adults (van Baaren, Holland, Kawakami, & van Knippenberg, 2004).…

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.

The flow and spray characteristics of gelled fluids; Die Stroemungs- und Verspruehungseigenschaften gelfoermiger Fluide

Energy Technology Data Exchange (ETDEWEB)

Madlener, K.

2008-07-01

In the present study gelled fluids are investigated concerning their application as propellants in storable and thrust controllable rocket propulsion systems. The correlations between the non-Newtonian viscosity properties and the flow and spray characteristics are discussed. Based on the proposed viscosity model Herschel-Bulkley-Extended (HBE) the laminar pipe flow is calculated for the investigated propellants. With the introduction of a generalized form of the Reynolds number and the presentation of a possibility to determine the critical values of this number it is possible to calculate the laminar-turbulent transition in a pipe flow. The theoretical results are evaluated with experimental data. The spray characteristics of various gelled fluids are examined using an experimental setup with impinging-jet-injectors. (orig.)

Mechanism of jet-flutter: self-induced oscillation of an upward plane jet impinging on a free surface

International Nuclear Information System (INIS)

Madarame, Haruki; Iida, Masao

1998-01-01

An upward plane jet impinging on the free surface of a shallow rectangular tank oscillates without any external periodic force. The movement of the impinging point leaves additional fluid mass on the surface behind the point, which does not balance the momentum supplied by the jet. The imbalance generates propagating waves, and a surface level gap appears there. The level gap is flattened not by the waves but by the vertical motion of water columns. The imbalance causes lateral displacement of jet, which in turn causes the imbalance, forming a positive feedback loop. The above model explains well why the frequency corresponds to that of water column oscillation in a partitioned tank with the same water depth, and the oscillation region has a wide range above a certain velocity limit determined by the water depth. (author)

Stem Cell Enrichment with Selectin Receptors: Mimicking the pH Environment of Trauma

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Michael R. King

2013-09-01

Full Text Available The isolation of hematopoietic stem and progenitor cells (HSPCs is critical for transplantation therapy and HSPC research, however current isolation techniques can be prohibitively expensive, time-consuming, and produce variable results. Selectin-coated microtubes have shown promise in rapidly isolating HSPCs from human bone marrow, but further purification of HSPCs remains a challenge. Herein, a biomimetic device for HSPC isolation is presented to mimic the acidic vascular microenvironment during trauma, which can enhance the binding frequency between L-selectin and its counter-receptor PSGL-1 and HSPCs. Under acidic pH conditions, L-selectin coated microtubes enhanced CD34+ HSPC adhesion, as evidenced by decreased cell rolling velocity and increased rolling flux. Dynamic light scattering was utilized as a novel sensor to confirm an L-selectin conformational change under acidic conditions, as previously predicted by molecular dynamics. These results suggest that mimicking the acidic conditions of trauma can induce a conformational extension of L-selectin, which can be utilized for flow-based, clinical isolation of HSPCs.

Gout: radiographic findings mimicking infection

International Nuclear Information System (INIS)

Rousseau, I.; Raymond-Tremblay, D.; Cardinal, E.; Beauregard, C.G.; Braunstein, E.M.; Saint-Pierre, A.

2001-01-01

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.)

Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages

International Nuclear Information System (INIS)

Hoshiba, Takashi; Tanaka, Masaru

2013-01-01

Highlights: •Models mimicking ECM in tumor with different malignancy were prepared. •Cancer cell proliferation was suppressed on benign tumor ECM. •Benign tumor cell proliferation was suppressed on cancerous ECM. •Chemoresistance of cancer cell was enhanced on cancerous ECM. -- Abstract: Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared “staged tumorigenesis-mimicking matrices” which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression

Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages

Energy Technology Data Exchange (ETDEWEB)

Hoshiba, Takashi [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510 (Japan); International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Tanaka, Masaru, E-mail: tanaka@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510 (Japan)

2013-09-20

Highlights: •Models mimicking ECM in tumor with different malignancy were prepared. •Cancer cell proliferation was suppressed on benign tumor ECM. •Benign tumor cell proliferation was suppressed on cancerous ECM. •Chemoresistance of cancer cell was enhanced on cancerous ECM. -- Abstract: Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared “staged tumorigenesis-mimicking matrices” which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression.

Impingement and entrainment: an updated annotated bibliography. Final report

International Nuclear Information System (INIS)

Yost, F.E.; Uziel, M.S.

1981-05-01

Presented as an annotated bibliography are 1343 references dealing with entrainment and impingement effects on aquatic organisms passing through the cooling systems of thermal power plants. The references were obtained from open literature and from environmental reports and impact statements prepared by or for the electric utility industry. Two earlier bibliographies contain literature from 1950 through 1976. This update contains additional literature acquired since 1976. Topics covered are site-specific field studies at facilities located on lakes, reservoirs, rivers, or estuaries. The studies include special engineering studies, laboratory studies, studies of biological effects, reviews and methodologies, and studies of the mitigation of effects. References are arranged alphabetically by author, and indexes are provided to personal and corporate authors, and to facility, waterbody, and taxonomic names

Aerodynamic and mass transfer characteristicsof an annular bistable impinging jet with a fluidic flip-flop control

Czech Academy of Sciences Publication Activity Database

Trávníček, Zdeněk; Peszynsky, K.; Hošek, Jan; Wawrzyniak, S.

2003-01-01

Roč. 46, č. 7 (2003), s. 1265-1278 ISSN 0017-9310 R&D Projects: GA AV ČR IBS2076301 Institutional research plan: CEZ:AV0Z2076919 Keywords : impinging jet * visualization * mass transfer Subject RIV: BK - Fluid Dynamics Impact factor: 1.293, year: 2003

Experimental study of curvature effects on jet impingement heat transfer on concave surfaces

Directory of Open Access Journals (Sweden)

Ying Zhou

2017-04-01

Full Text Available Experimental study of the local and average heat transfer characteristics of a single round jet impinging on the concave surfaces was conducted in this work to gain in-depth knowledge of the curvature effects. The experiments were conducted by employing a piccolo tube with one single jet hole over a wide range of parameters: jet Reynolds number from 27000 to 130000, relative nozzle to surface distance from 3.3 to 30, and relative surface curvature from 0.005 to 0.030. Experimental results indicate that the surface curvature has opposite effects on heat transfer characteristics. On one hand, an increase of relative nozzle to surface distance (increasing jet diameter in fact enhances the average heat transfer around the surface for the same curved surface. On the other hand, the average Nusselt number decreases as relative nozzle to surface distance increases for a fixed jet diameter. Finally, experimental data-based correlations of the average Nusselt number over the curved surface were obtained with consideration of surface curvature effect. This work contributes to a better understanding of the curvature effects on heat transfer of a round jet impingement on concave surfaces, which is of high importance to the design of the aircraft anti-icing system.

Cutaneous Silicone Granuloma Mimicking Breast Cancer after Ruptured Breast Implant

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Waseem Asim Ghulam El-Charnoubi

2011-01-01

Full Text Available Cutaneous manifestations due to migration of silicone from ruptured implants are rare. Migrated silicone with cutaneous involvement has been found in the chest wall, abdominal wall, and lower extremities. We describe a case of cutaneous silicone granuloma in the breast exhibiting unusual growth mimicking breast cancer after a ruptured implant.

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 conditions applied is given in Figure 2. Figures 3 to 7 give an overview of the final mesh and some idea of the block structured approach and refinement in the main area of interest, that is, the impingement zone and metering holes at the lower part... 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...

A pacemaker powered by an implantable biofuel cell operating under conditions mimicking the human blood circulatory system--battery not included.

Science.gov (United States)

Southcott, Mark; MacVittie, Kevin; Halámek, Jan; Halámková, Lenka; Jemison, William D; Lobel, Robert; Katz, Evgeny

2013-05-07

Biocatalytic electrodes made of buckypaper were modified with PQQ-dependent glucose dehydrogenase on the anode and with laccase on the cathode and were assembled in a flow biofuel cell filled with serum solution mimicking the human blood circulatory system. The biofuel cell generated an open circuitry voltage, Voc, of ca. 470 mV and a short circuitry current, Isc, of ca. 5 mA (a current density of 0.83 mA cm(-2)). The power generated by the implantable biofuel cell was used to activate a pacemaker connected to the cell via a charge pump and a DC-DC converter interface circuit to adjust the voltage produced by the biofuel cell to the value required by the pacemaker. The voltage-current dependencies were analyzed for the biofuel cell connected to an Ohmic load and to the electronic loads composed of the interface circuit, or the power converter, and the pacemaker to study their operation. The correct pacemaker operation was confirmed using a medical device - an implantable loop recorder. Sustainable operation of the pacemaker was achieved with the system closely mimicking human physiological conditions using a single biofuel cell. This first demonstration of the pacemaker activated by the physiologically produced electrical energy shows promise for future electronic implantable medical devices powered by electricity harvested from the human body.

Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.

Science.gov (United States)

Henkel, S; Beyrau, F; Hardalupas, Y; Taylor, A M K P

2016-02-08

This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated.

A Q fever case mimicking crimean-congo haemorrhagic fever

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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.

The anti-corrosion behavior under multi-factor impingement of Hastelloy C22 coating prepared by multilayer laser cladding

Science.gov (United States)

Chen, Lin; Bai, Shu-Lin

2018-04-01

Hastelloy C22 coating was prepared on substrate of Q235 steel by high power multilayer laser cladding. The microstructure, hardness and anti-corrosion properties of coating were investigated. The corrosion tests in 3.5% NaCl solution were carried out with variation of impingement angle and velocity, and vibration frequency of sample. The microstructure of coating changes from equiaxed grain at the top surface to dendrites oriented at an angle of 60° to the substrate inside the coating. The corrosion rate of coating increases with the increase of impingement angle and velocity, and vibrant frequency of sample. Corrosion mechanisms relate to repassivation and depassivation of coating according to electrochemical measurements. Above results show that multilayer laser cladding can endow Hastelloy C22 coating with fine microstructures, high hardness and good anti-corrosion performances.

Estimation of energy saving thanks to a reduced-model-based approach: Example of bread baking by jet impingement

International Nuclear Information System (INIS)

Alamir, M.; Witrant, E.; Della Valle, G.; Rouaud, O.; Josset, Ch.; Boillereaux, L.

2013-01-01

In this paper, a reduced order mechanistic model is proposed for the evolution of temperature and humidity during French bread baking. The model parameters are identified using experimental data. The resulting model is then used to estimate the potential energy saving that can be obtained using jet impingement technology when used to increase the heat transfer efficiency. Results show up to 16% potential energy saving under certain assumptions. - Highlights: ► We developed a mechanistic model of heat and mass transfer in bread including different and multiple energy sources. ► An optimal control system permits to track references trajectories with a minimization of energy consuming. ► The methodology is evaluated with jet impingement technique. ► Results show a significant energy saving of about 17% of energy with reasonable actuator variations

Conservative management of an elite ice hockey goaltender with femoroacetabular impingement (FAI): a case report

Science.gov (United States)

MacIntyre, Kyle; Gomes, Brendan; MacKenzie, Steven; D’Angelo, Kevin

2015-01-01

Objective: To detail the presentation of an elite male ice hockey goaltender with cam-type femoroacetabular impingement (FAI) and acetabular labral tears. This case will outline the prevalence, clinical presentation, imaging criteria, pathomechanics, and management of FAI, with specific emphasis on the ice hockey goaltender. Clinical Features: A 22-year old retired ice hockey goaltender presented to a chiropractor after being diagnosed by an orthopaedic surgeon with MRI confirmed left longitudinal and chondral flap acetabular labral tears and cam-type femoroacetabular impingement (FAI). As the patient was not a candidate for surgical intervention, a multimodal conservative treatment approach including manual therapy, electroacupuncture and rehabilitation exercises were implemented. Summary: FAI is prevalent in ice hockey players, particularly with goaltenders. Both skating and position-dependent hip joint mechanics involved in ice hockey may exacerbate or contribute to acquired and congenital forms of symptomatic FAI. As such, practitioners managing this population must address sport-specific demands in manual therapy, rehabilitation and physical training, to improve functional outcomes and prevent future injury. PMID:26816416

Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies

OpenAIRE

Mayne, E; Memarzadeh, A; Raut, P; Arora, A; Khanduja, Vikas

2017-01-01

$\\textbf{Objectives}$ The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field. $\\textbf{Methods}$ The Cochrane and PubMed libraries were searched for any publications using the terms ‘hip’, ‘muscle’, ‘strength’, and ‘measurement’ in the ‘Title, Abstract, Keywords’ field. A further sea...

Sparganosis of the Breast that Mimicked Metastasis: A Case Report

International Nuclear Information System (INIS)

Kim, Jae Woon; Hwang, Mi Soo

2011-01-01

Sparganosis of the breast is a rare parasitic infection of humans. If the breast is involved, then this condition presents as soft tissue masses that mimic breast cancer. We report here on the radiologic feature of sparganosis in a patient with gastric cancer and this mimicked metastasis. We also briefly review the relevant literature

Orthokeratinised odontogenic cyst mimicking periapical cyst.

Science.gov (United States)

Rajalakshmi, R; Sreeja, C; Vijayalakshmi, D; Leelarani, V

2013-10-07

Orthokeratinised odontogenic cyst (OOC) denotes the odontogenic cyst that microscopically has an orthokeratinised epithelial lining. OOC is characterised by a less-aggressive behaviour and a low rate of recurrence. This report describes a case of OOC involving posterior part of the mandible that mimicked periapical cyst in a 14-year-old boy. The initial clinical diagnosis was given as periapical cyst based on the clinical and radiographical features. Enucleation of the cyst was performed and the specimen was sent for histopathological examination. A definite diagnosis of OOC was made by histopathological examination of the biopsy specimen. This case emphases on including OOC in the differential diagnosis of radiolucencies occurring in the periapical region of non-vital tooth.

CFD study of fluid flow changes with erosion

Science.gov (United States)

López, Alejandro; Stickland, Matthew T.; Dempster, William M.

2018-06-01

For the first time, a three dimensional mesh deformation algorithm is used to assess fluid flow changes with erosion. The validation case chosen is the Jet Impingement Test, which was thoroughly analysed in previous works by Hattori et al. (Kenichi Sugiyama and Harada, 2008), Gnanavelu et al. in (Gnanavelu et al., 2009, 2011), Lopez et al. in (Lopez et al., 2015) and Mackenzie et al. in (Mackenzie et al., 2015). Nguyen et al. (2014) showed the formation of a new stagnation area when the wear scar is deep enough by performing a three-dimensional scan of the wear scar after 30 min of jet impingement test. However, in the work developed here, this stagnation area was obtained solely by computational means. The procedure consisted of applying an erosion model in order to obtain a deformed geometry, which, due to the changes in the flow pattern lead to the formation of a new stagnation area. The results as well as the wear scar were compared to the results by Nguyen et al. (2014) showing the same trend. OpenFOAM® was the software chosen for the implementation of the deforming mesh algorithm as well as remeshing of the computational domain after deformation. Different techniques for mesh deformation and approaches to erosion modelling are discussed and a new methodology for erosion calculation including mesh deformation is developed. This new approach is independent of the erosion modelling approach, being applicable to both Eulerian and Lagrangian based equations for erosion calculation. Its different applications such as performance decay in machinery subjected to erosion as well as modelling of natural erosion processes are discussed here.

Hip arthroscopy with labral repair for femoroacetabular impingement

DEFF Research Database (Denmark)

Dippmann, Christian; Thorborg, Kristian; Kraemer, Otto

2014-01-01

PURPOSE: The purpose of this study was to examine the progression of clinical outcomes 3, 6 and 12 months after hip arthroscopy with labral repair for femoroacetabular impingement (FAI). METHODS: From May 2009 to December 2011, 87 consecutive patients [55 females (median age 38, range 17-63) and 32...... males (median age 38, range 15-59)] underwent hip arthroscopy and labral repair, by the same experienced surgeon. Standardised, but unstructured, post-operative rehabilitation instructions were provided. Function and pain were evaluated using modified Harris Hip Score (mHHS) and visual analogue scale...... months with no additional changes from 6 to 12 months [22.6 (2.6)-27.9 (2.6), (n.s.)]. CONCLUSIONS: Improvements in function (mHHS) and pain (VAS) were seen in patients after hip arthroscopy with labral repair for FAI at 3, 6, and 12 months. While significant improvements occurred from 3 to 6 months...

Sports hernia and femoroacetabular impingement in athletes: A systematic review.

Science.gov (United States)

Munegato, Daniele; Bigoni, Marco; Gridavilla, Giulia; Olmi, Stefano; Cesana, Giovanni; Zatti, Giovanni

2015-09-16

To investigate the association between sports hernias and femoroacetabular impingement (FAI) in athletes. PubMed, MEDLINE, CINAHL, Embase, Cochrane Controlled Trials Register, and Google Scholar databases were electronically searched for articles relating to sports hernia, athletic pubalgia, groin pain, long-standing adductor-related groin pain, Gilmore groin, adductor pain syndrome, and FAI. The initial search identified 196 studies, of which only articles reporting on the association of sports hernia and FAI or laparoscopic treatment of sports hernia were selected for systematic review. Finally, 24 studies were reviewed to evaluate the prevalence of FAI in cases of sports hernia and examine treatment outcomes and evidence for a common underlying pathogenic mechanism. FAI has been reported in as few as 12% to as high as 94% of patients with sports hernias, athletic pubalgia or adductor-related groin pain. Cam-type impingement is proposed to lead to increased symphyseal motion with overload on the surrounding extra-articular structures and muscle, which can result in the development of sports hernia and athletic pubalgia. Laparoscopic repair of sports hernias, via either the transabdominal preperitoneal or extraperitoneal approach, has a high success rate and earlier recovery of full sports activity compared to open surgery or conservative treatment. For patients with FAI and sports hernia, the surgical management of both pathologies is more effective than sports pubalgia treatment or hip arthroscopy alone (89% vs 33% of cases). As sports hernias and FAI are typically treated by general and orthopedic surgeons, respectively, a multidisciplinary approach for diagnosis and treatment is recommended for optimal treatment of patients with these injuries. The restriction in range of motion due to FAI likely contributes to sports hernias; therefore, surgical treatment of both pathologies represents an optimal therapy.

Role of the confinement of a root canal on jet impingement during endodontic irrigation

Science.gov (United States)

Verhaagen, B.; Boutsioukis, C.; Heijnen, G. L.; van der Sluis, L. W. M.; Versluis, M.

2012-12-01

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 experimentally with high-speed Particle Imaging Velocimetry, inside and outside the confinement (concave surface) of a root canal, and compared to theoretical predictions for these jets. The efficacy of irrigation fluid refreshment with respect to the typical reaction time of the antimicrobial fluid with a biofilm is characterized with a non-dimensional Damköhler number. The pressure that these jets induce on a wall or at the apex of the root canal is also measured. The axisymmetric jet is found to be stable and its velocity agrees with the theoretical prediction for this type of jet, however, a confinement causes instabilities to the jet. The confinement of the root canal has a pronounced influence on the flow, for both the axisymmetric and non-axisymmetric jet, by reducing the velocities by one order of magnitude and increasing the pressure at the apex. The non-axisymmetric jet inside the confinement shows a cascade of eddies with decreasing velocities, which at the apex does not provide adequate irrigation fluid refreshment.

Cutaneous lymphoid hyperplasia mimicking cutaneous lymphoma in a hyperthyroid cat

OpenAIRE

Snead, Elisabeth; Kerr, Moira; MacDonald, Valerie

2013-01-01

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.

Giant Spermatocele Mimicking Hydrocele: A Case Report

Directory of Open Access Journals (Sweden)

Hsin-Chih Yeh

2007-07-01

Full Text Available Spermatoceles are usually asymptomatic and often found incidentally during physical examination. We report a case of giant spermatocele that mimicked a hydrocele. A 55-year-old man suffered from right scrotal enlargement for several years. As the heavy sensation and scrotal soreness worsened in recent months, he came to our outpatient clinic for help. Hydrocele was suspected due to transilluminating appearance of the scrotal content. Surgical exploration was arranged and a giant spermatocele was found. Total excision of the spermatocele was performed and the patient recovered well. The specimen was sent for pathology and spermatocele with spermatozoa was noted.

Floating retained root lesion mimicking apical periodontitis.

Science.gov (United States)

Chung, Ming-Pang; Chen, Chih-Ping; Shieh, Yi-Shing

2009-10-01

A case of a retained root tip simulating apical periodontitis on radiographic examination is described. The retained root tip, originating from the left lower first molar, floated under the left lower second premolar apical region mimicking apical periodontitis. It appeared as an ill-defined periapical radiolucency containing a smaller radiodense mass on radiograph. The differential diagnosis included focal sclerosing osteomyelitis (condensing osteitis) and ossifying fibroma. Upon exicisional biopsy, a retained root associated with granulation tissue was found. After 1-year follow-up, the patient was asymptomatic and the periradicular lesion was healing. Meanwhile, the associated tooth showed a normal response to stimulation testing.

Unusual presentation of chondroblastoma mimicking Trevor's disease

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Y Karkhur

2017-01-01

Full Text Available Chondroblastoma is a benign bone tumor, represents 1%–2% of all primary bone tumors, typically seen in patients 10–25-year-old and more common in males. It occurs most frequently in the distal femur, proximal tibia, and proximal humerus. Soft tissue extension is extremely rare. Adjacent joints may develop effusions, but the tumor mass protruding into the joint has never been seen in case of chondroblastoma. We report a rare case of intra-articular chondroblastoma arising from proximal tibia in a 16-year-old boy and growing into the knee joint mimicking an intra-articular osteochondroma.

Outcome of pinning in patients with slipped capital femoral epiphysis: risk factors associated with avascular necrosis, chondrolysis, and femoral impingement.

Science.gov (United States)

Ulici, Alexandru; Carp, Madalina; Tevanov, Iulia; Nahoi, Catalin Alexandru; Sterian, Alin Gabriel; Cosma, Dan

2018-06-01

Objective This study aimed to assess the principal risk factors that could lead to the most common long-term complications of slipped capital femoral epiphysis, such as avascular necrosis, chondrolysis, and hip impingement. Methods We conducted a single-centre, retrospective study and evaluated patients (70 patients, 81 hips) who were treated for slipped capital femoral epiphysis from 2010 to 2015 and who underwent pinning. We measured the severity of displacement radiologically using the Southwick angle. Postoperative radiographs were evaluated for the most frequent long-term complications of avascular necrosis (AVN), chondrolysis, and femoral acetabular impingement (FAI). Results We found seven cases of AVN, 14 cases of chondrolysis, and 31 hips had an α angle of 60°. Sex, ambulation, and symptoms did not affect development of these complications. Patients with a normal weight were almost two times more likely to develop FAI. Patients with moderate and severe slips had a similar percentage of AVN. In severe slips, 85.7% of patients had an α angle higher than 60°. Conclusions This study shows that severe slips have a higher risk of developing AVN and hip impingement. Every patient who suffers from SCFE (even the mildest forms) should be regularly checked for FAI.

Range of impingement-free abduction and adduction deficit after reverse shoulder arthroplasty. Hierarchy of surgical and implant-design-related factors.

Science.gov (United States)

Gutiérrez, Sergio; Comiskey, Charles A; Luo, Zong-Ping; Pupello, Derek R; Frankle, Mark A

2008-12-01

Evaluations of functional outcomes of reverse shoulder arthroplasty have revealed variable improvements in the range of motion and high rates of scapular notching. The purpose of this study was to systematically examine the impact of surgical factors (location of the glenosphere on the glenoid and tilt angle of the glenosphere on the glenoid) and implant-related factors (implant size, center-of-rotation offset, and humeral neck-shaft angle) on impingement-free abduction motion. A computer model was developed to virtually simulate abduction/adduction motion and its dependence on five surgical and implant-related factors. Three conditions were tested for each factor, resulting in a total of 243 simulated combinations. The overall motion was determined from 0 degrees of abduction until maximum abduction, which would be limited by impingement of the humerosocket on the scapula. In those combinations in which 0 degrees of abduction could not be achieved, the adduction deficit was recorded. The largest average increase in the range of impingement-free abduction motion resulted from a more lateral center-of-rotation offset: the average increase was 31.9 degrees with a change in the center-of-rotation offset from 0 to 10 mm, and this change resulted in an increase in abduction motion in eighty of the eighty-one combinations. The position of the glenosphere on the glenoid was associated with the second largest average increase in abduction motion (28.1 degrees when the glenosphere position was changed from superior to inferior, with the change resulting in an increase in seventy-one of the eighty-one combinations). These factors were followed by glenosphere tilt, humeral neck-shaft angle, and prosthetic size in terms of their effects on abduction motion. The largest effect in terms of avoiding an adduction deficit was provided by a humeral neck-shaft angle of 130 degrees (the deficit was avoided in forty-nine of the eighty-one combinations in which this angle was used

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...... developed recently and have not been established in the literature. Although currently used generic and activity-level measures have limitations, as well, they should be considered, depending on the specific goals of the study. Additional research is needed to assess the properties of these measures fully...

Cartilage Delamination Flap Mimicking a Torn Medial Meniscus

Directory of Open Access Journals (Sweden)

Gan Zhi-Wei Jonathan

2016-01-01

Full Text Available We report a case of a chondral delamination lesion due to medial parapatellar plica friction syndrome involving the medial femoral condyle. This mimicked a torn medial meniscus in clinical and radiological presentation. Arthroscopy revealed a chondral delamination flap, which was debrided. Diagnosis of chondral lesions in the knee can be challenging. Clinical examination and MRI have good accuracy for diagnosis and should be used in tandem. Early diagnosis and treatment of chondral lesions are important to prevent progression to early osteoarthritis.

Software documentation and user's manual for fish-impingement sampling design and estimation method computer programs

International Nuclear Information System (INIS)

Murarka, I.P.; Bodeau, D.J.

1977-11-01

This report contains a description of three computer programs that implement the theory of sampling designs and the methods for estimating fish-impingement at the cooling-water intakes of nuclear power plants as described in companion report ANL/ES-60. Complete FORTRAN listings of these programs, named SAMPLE, ESTIMA, and SIZECO, are given and augmented with examples of how they are used

Modification of Aortic Cannula With an Inlet Chamber to Induce Spiral Flow and Improve Outlet Flow.

Science.gov (United States)

Darlis, Nofrizalidris; Osman, Kahar; Padzillah, Muhamad Hasbullah; Dillon, Jeswant; Md Khudzari, Ahmad Zahran

2018-05-01

Physiologically, blood ejected from the left ventricle in systole exhibited spiral flow characteristics. This spiral flow has been proven to have several advantages such as lateral reduction of directed forces and thrombus formation, while it also appears to be clinically beneficial in suppressing neurological complications. In order to deliver spiral flow characteristics during cardiopulmonary bypass operation, several modifications have been made on an aortic cannula either at the internal or at the outflow tip; these modifications have proven to yield better hemodynamic performances compared to standard cannula. However, there is no modification done at the inlet part of the aortic cannula for inducing spiral flow so far. This study was carried out by attaching a spiral inducer at the inlet of an aortic cannula. Then, the hemodynamic performances of the new cannula were compared with the standard straight tip end-hole cannula. This is achieved by modeling the cannula and attaching the cannula at a patient-specific aorta model. Numerical approach was utilized to evaluate the hemodynamic performance, and a water jet impact experiment was used to demonstrate the jet force generated by the cannula. The new spiral flow aortic cannula has shown some improvements by reducing approximately 21% of impinging velocity near to the aortic wall, and more than 58% reduction on total force generated as compared to standard cannula. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Radiological diagnosis of femoroacetabular impingement

International Nuclear Information System (INIS)

Mamisch, T.C.; Werlen, S.; Trattnig, S.; Zilkens, C.; Kim, Y.J.; Siebenrock, K.A.; Bittersohl, B.

2009-01-01

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.) [de

Huge Dermatofibrosarcoma Protuberans Mimicking a Breast Malignant Tumor with Abscess

Directory of Open Access Journals (Sweden)

Han-Kun Chen

2014-12-01

Full Text Available Dermatofibrosarcoma protuberans (DFSP is an uncommon skin cancer that most commonly occurs on the trunk and extremities. DFSP of the breast has rarely been reported, and then is almost always of small size. We report a case of rapid-growing DFSP of the breast with abscess formation mimicking breast cancer, and also make a review of related literature.

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.

A case of gallbladder mass: Malakoplakia (The tumor mimicker

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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.

Contribution of full-thickness supraspinatus tendon tears to acquired subcoracoid impingement

Energy Technology Data Exchange (ETDEWEB)

MacMahon, P.J. [Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin (Ireland)]. E-mail: petermacmahon@yahoo.com; Taylor, D.H. [Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin (Ireland); Duke, D. [Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin (Ireland); Brennan, D.D. [Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin (Ireland); O' Brien, J. [Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin (Ireland); Eustace, S.J. [Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin (Ireland)

2007-06-15

Aim: To assess the relationship between the severity of full-thickness supraspinatus tendon tears and the development of subcoracoid impingement. Materials and methods: Fifty-one magnetic resonance imaging (MRI) shoulder examination reports with full-thickness supraspinatus tears were retrospectively identified and reviewed by two dedicated musculoskeletal radiologists. The appearances of the rotator cuff muscles, biceps tendon and the lesser tubercle were recorded. The acromio-humeral distance and the axial coraco-humeral distance were measured. The data were recorded and analysed electronically. Results: The kappa values for inter-observer agreement were: 0.91 for acromio-humeral distance and 0.85 for coraco-humeral distance measurements. Twenty-six patients had significant retraction of the supraspinatus tendon, 85% (22 cases) of this group had imaging evidence of tear or tendonopathy of the subscapularis tendon. Twenty-five patients had no significant retraction of the supraspinatus, 56% (14 cases) of this group had imaging evidence of a subscapularis tear or tendonopathy. The acromio-humeral distance was significantly less in patients with supraspinatus tears and retraction (p < 0.05). The subscapularis tendon was significantly more likely to be abnormal if the supraspinatus was retracted than if no retraction was present (p < 0.05). There were no significant differences in coraco-humeral distances between the groups. Conclusion: Subscapularis tendon signal and structural changes are frequently associated with full-thickness supraspinatus tendon tears, particularly if the supraspinatus is significantly retracted. In this static MRI series, the data do not support the occurrence of classical subcoracoid impingement as an aetiology; however, they may support the possibility of a dynamic mechanism, to which future studies could be directed.

Contribution of full-thickness supraspinatus tendon tears to acquired subcoracoid impingement

International Nuclear Information System (INIS)

MacMahon, P.J.; Taylor, D.H.; Duke, D.; Brennan, D.D.; O'Brien, J.; Eustace, S.J.

2007-01-01

Aim: To assess the relationship between the severity of full-thickness supraspinatus tendon tears and the development of subcoracoid impingement. Materials and methods: Fifty-one magnetic resonance imaging (MRI) shoulder examination reports with full-thickness supraspinatus tears were retrospectively identified and reviewed by two dedicated musculoskeletal radiologists. The appearances of the rotator cuff muscles, biceps tendon and the lesser tubercle were recorded. The acromio-humeral distance and the axial coraco-humeral distance were measured. The data were recorded and analysed electronically. Results: The kappa values for inter-observer agreement were: 0.91 for acromio-humeral distance and 0.85 for coraco-humeral distance measurements. Twenty-six patients had significant retraction of the supraspinatus tendon, 85% (22 cases) of this group had imaging evidence of tear or tendonopathy of the subscapularis tendon. Twenty-five patients had no significant retraction of the supraspinatus, 56% (14 cases) of this group had imaging evidence of a subscapularis tear or tendonopathy. The acromio-humeral distance was significantly less in patients with supraspinatus tears and retraction (p < 0.05). The subscapularis tendon was significantly more likely to be abnormal if the supraspinatus was retracted than if no retraction was present (p < 0.05). There were no significant differences in coraco-humeral distances between the groups. Conclusion: Subscapularis tendon signal and structural changes are frequently associated with full-thickness supraspinatus tendon tears, particularly if the supraspinatus is significantly retracted. In this static MRI series, the data do not support the occurrence of classical subcoracoid impingement as an aetiology; however, they may support the possibility of a dynamic mechanism, to which future studies could be directed

Femoroacetabular impingement: bone marrow oedema associated with fibrocystic change of the femoral head and neck junction

Energy Technology Data Exchange (ETDEWEB)

James, S.L.J. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom) and Department of Radiology, Royal Orthopaedic Hospital, Birmingham (United Kingdom)]. E-mail: jamesslj@email.com; Connell, D.A. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom); O' Donnell, P. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom); Saifuddin, A. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom)

2007-05-15

Aim: To describe the association of bone marrow oedema adjacent to areas of fibrocystic change at the femoral head and neck junction in patients with femoroacetabular impingement. Materials and methods: The clinical and imaging findings in six patients with bone marrow oedema adjacent to an area of fibrocystic change at the femoral head and neck junction are presented. There were five males and one female (age range 19-42 years, mean age 34.5 years). Three patients were referred with a clinical suspicion of femoroacetabular impingement, two with suspected osteoid osteoma and one with a clinical diagnosis of sciatica. The volume of bone marrow oedema (grade 1: 0-25%, grade 2: 26-50%, grade 3: 51-75% and grade 4: 76-100% of the femoral neck width), presence of labral and articular cartilage abnormality, joint effusion, and femoral head and neck morphology were recorded. Results: Magnetic resonance imaging (MRI) identified fibrocystic change in the anterolateral aspect of the femoral head and neck junction in all cases (mean size 9 mm, range 5-14 mm, three multilocular and three unilocular cysts). The volume of oedema was variable (one grade 1, two grade 2, one grade 3 and two grade 4). All patients had abnormality of the anterosuperior labrum with five patients demonstrating chondral loss. An abnormal femoral head and neck junction was identified in five patients. Conclusion: The radiological finding of fibrocystic change at the anterosuperior femoral neck with or without bone marrow oedema should prompt the search for femoroacetabular impingement. Bone marrow oedema may rarely be identified adjacent to these areas of cystic change and should be considered in the differential diagnosis of bone marrow oedema in the femoral neck.

Femoroacetabular impingement: bone marrow oedema associated with fibrocystic change of the femoral head and neck junction

International Nuclear Information System (INIS)

James, S.L.J.; Connell, D.A.; O'Donnell, P.; Saifuddin, A.

2007-01-01

Aim: To describe the association of bone marrow oedema adjacent to areas of fibrocystic change at the femoral head and neck junction in patients with femoroacetabular impingement. Materials and methods: The clinical and imaging findings in six patients with bone marrow oedema adjacent to an area of fibrocystic change at the femoral head and neck junction are presented. There were five males and one female (age range 19-42 years, mean age 34.5 years). Three patients were referred with a clinical suspicion of femoroacetabular impingement, two with suspected osteoid osteoma and one with a clinical diagnosis of sciatica. The volume of bone marrow oedema (grade 1: 0-25%, grade 2: 26-50%, grade 3: 51-75% and grade 4: 76-100% of the femoral neck width), presence of labral and articular cartilage abnormality, joint effusion, and femoral head and neck morphology were recorded. Results: Magnetic resonance imaging (MRI) identified fibrocystic change in the anterolateral aspect of the femoral head and neck junction in all cases (mean size 9 mm, range 5-14 mm, three multilocular and three unilocular cysts). The volume of oedema was variable (one grade 1, two grade 2, one grade 3 and two grade 4). All patients had abnormality of the anterosuperior labrum with five patients demonstrating chondral loss. An abnormal femoral head and neck junction was identified in five patients. Conclusion: The radiological finding of fibrocystic change at the anterosuperior femoral neck with or without bone marrow oedema should prompt the search for femoroacetabular impingement. Bone marrow oedema may rarely be identified adjacent to these areas of cystic change and should be considered in the differential diagnosis of bone marrow oedema in the femoral neck

Full experimental modelling of a liver tissue mimicking phantom for medical ultrasound studies employing different hydrogels.

Science.gov (United States)

Casciaro, Sergio; Conversano, Francesco; Musio, Stefano; Casciaro, Ernesto; Demitri, Christian; Sannino, Alessandro

2009-04-01

Tissue mimicking phantoms have been widely reported to be an important tool for development, optimisation and performance testing of ultrasound-based diagnostic techniques. In particular, modern applications of tissue mimicking phantoms often include characterisation of the nonlinear behaviour of experimental ultrasound contrast agents. In such cases, the tissue-mimicking materials should be chosen not only based on the values of their density, speed of sound and attenuation coefficient, but also considering their effect on the appearance of "native harmonics" due to nonlinear distortion of ultrasound signal during propagation. In a previous paper it was demonstrated that a cellulose-based hydrogel is suitable to simulate nonlinear acoustical behaviour of liver tissue for thicknesses up to 8 cm. In this paper we present the experimental characterisation of the nonlinear acoustical behaviour of a different polyethylene glycol diacrylate (PEGDA)-based hydrogel, in order to assess whether and how it can improve the performances and overcome some limitations of the cellulose-based hydrogel as liver tissue-mimicking material. Samples of pig liver tissue, cellulose-based hydrogel and PEGDA-based hydrogel were insonified in a through-transmission set-up, employing 2.25-MHz pulses with different mechanical index (MI) values. Second harmonic and first harmonic amplitudes were extracted from the spectra of received signals and their difference was then used to compare sample behaviours. Obtained results show how a new more accurate and combined experimental model of linear and nonlinear acoustical behaviour of liver tissue is feasible. In fact, a further confirmation of the cellulose-based hydrogel effectiveness to precisely simulate the liver tissue for penetration depths up to 8 cm was provided, and it was also shown that the employment of the PEGDA-based hydrogel can extend the range of useful tissue-mimicking material thicknesses up to 11 cm, moreover allowing a

Wave structure in the radial film flow with a circular hydraulic jump

Science.gov (United States)

Rao, A.; Arakeri, J. H.

A circular hydraulic jump is commonly seen when a circular liquid jet impinges on a horizontal plate. Measurements of the film thickness, jump radius and the wave structure for various jet Reynolds numbers are reported. Film thickness measurements are made using an electrical contact method for regions both upstream and downstream of the jump over circular plates without a barrier at the edge. The jump radius and the separation bubble length are measured for various flow rates, plate edge conditions, and radii. Flow visualization using high-speed photography is used to study wave structure and transition. Waves on the jet amplify in the film region upstream of the jump. At high flow rates, the waves amplify enough to cause three-dimensional breakdown and what seems like transition to turbulence. This surface wave induced transition is different from the traditional route and can be exploited to enhance heat and mass transfer rates.

Nephrogenic rests mimicking Wilms' tumor on CT

International Nuclear Information System (INIS)

Subhas, Naveen; Siegelman, Stanley S.; Argani, Pedram; Gearhart, John P.

2004-01-01

Nephrogenic rests (NR) are persistent benign remnants of embryonic renal tissue. A small percentage of these may develop into Wilms' tumor (WT). Radiologic imaging is relied upon to differentiate between these entities, with the hallmark of malignant transformation being growth on serial imaging studies. There is, however, considerable overlap in their imaging characteristics. The authors present a case of two biopsy-proven NR in a 2-year-old girl with sporadic aniridia that were indistinguishable from WT on initial radiologic studies. One of the NR grew on serial imaging studies mimicking a WT, but after resection was confirmed to be a benign hyperplastic NR on pathologic examination. (orig.)

The Role of Femoroacetabular Impingement in Core Muscle Injury/Athletic Pubalgia: Diagnosis and Management

OpenAIRE

Strosberg, David S.; Ellis, Thomas J.; Renton, David B.

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...

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.)

Core Muscle Injury/Sports Hernia/Athletic Pubalgia, and Femoroacetabular Impingement.

Science.gov (United States)

Ross, James R; Stone, Rebecca M; Larson, Christopher M

2015-12-01

Core muscle injury/sports hernia/athletic pubalgia is an increasingly recognized source of pain, disability, and time lost from athletics. Groin pain among athletes, however, may be secondary to various etiologies. A thorough history and comprehensive physical examination, coupled with appropriate diagnostic imaging, may improve the diagnostic accuracy for patients who present with core muscular injuries. Outcomes of nonoperative management have not been well delineated, and multiple operative procedures have been discussed with varying return-to-athletic activity rates. In this review, we outline the clinical entity and treatment of core muscle injury and athletic pubalgia. In addition, we describe the relationship between athletic pubalgia and femoroacetabular impingement along with recent studies that have investigated the treatment of these related disorders.

Pleural pneumatocoeles mimicking congenital cystic adenomatoid malformation of the lung. A case report

International Nuclear Information System (INIS)

Aurora, P.; McHugh, K.

1998-01-01

We present the plain radiographic and CT appearances of large intrapleural pneumatocoeles in a 13-week-old infant, resulting in compression atelectasis of the left upper and lower lobes, and mimicking congenital cystic adenomatoid malformation. (orig.)

Effect of baseplate size on primary glenoid stability and impingement-free range of motion in reverse shoulder arthroplasty.

Science.gov (United States)

Chae, Soo-Won; Kim, Soung-Yon; Lee, Haea; Yon, Joung-Ro; Lee, Juneyoung; Han, Seung-Ho

2014-12-09

Use of a baseplate with a smaller diameter in reverse shoulder arthroplasty is increasing, especially in patients with a small glenoid or glenoid wear. However, the effect of a smaller baseplate on stability of the glenoid component has not been evaluated. Thus, the purpose of this study was to determine whether a smaller baseplate (25 mm) is beneficial to the initial stability of the glenoid component compared to that with a baseplate of a commonly used size (29 mm). Micromotion of glenoid components attached to 14 scapulae of fresh-frozen cadavers was measured and compared between 25- and 29-mm baseplates in biomechanical testing. Impingement-free range of motion in abduction, adduction, internal rotation, and external rotation was evaluated by using a simulated computer model constructed based on the same fresh-frozen cadavers used in biomechanical testing. Micromotion at the inferior third of the glenoid-glenosphere interface was higher in the 29-mm baseplate group than in the 25-mm baseplate group during both 0.7- and 1-body weight cyclic loading in biomechanical testing. Adduction deficit was smaller, and total impingement-free range of motion from abduction to adduction and rotation were greater in the 25-mm baseplate group than in the 29-mm baseplate group in the simulated computer model. Use of a baseplate with a smaller diameter (25 mm) in reverse shoulder arthroplasty is suitable for improving the primary stability of the glenoid component. With a smaller baseplate, impingement-free range of motion is optimized in a smaller glenoid.

A Lagrangian parcel based mixing plane method for calculating water based mixed phase particle flows in turbo-machinery

Science.gov (United States)

Bidwell, Colin S.

2015-05-01

A method for calculating particle transport through turbo-machinery using the mixing plane analogy was developed and used to analyze the energy efficient engine . This method allows the prediction of temperature and phase change of water based particles along their path and the impingement efficiency and particle impact property data on various components in the engine. This methodology was incorporated into the LEWICE3D V3.5 software. The method was used to predict particle transport in the low pressure compressor of the . The was developed by NASA and GE in the early 1980s as a technology demonstrator and is representative of a modern high bypass turbofan engine. The flow field was calculated using the NASA Glenn ADPAC turbo-machinery flow solver. Computations were performed for a Mach 0.8 cruise condition at 11,887 m assuming a standard warm day for ice particle sizes of 5, 20 and 100 microns and a free stream particle concentration of . The impingement efficiency results showed that as particle size increased average impingement efficiencies and scoop factors increased for the various components. The particle analysis also showed that the amount of mass entering the inner core decreased with increased particle size because the larger particles were less able to negotiate the turn into the inner core due to particle inertia. The particle phase change analysis results showed that the larger particles warmed less as they were transported through the low pressure compressor. Only the smallest 5 micron particles were warmed enough to produce melting with a maximum average melting fraction of 0.18. The results also showed an appreciable amount of particle sublimation and evaporation for the 5 micron particles entering the engine core (22.6 %).

Solid-phase synthesis of an apoptosis-inducing tetrapeptide mimicking the Smac protein

DEFF Research Database (Denmark)

Le Quement, Sebastian Thordal; Ishøy, Mette; Petersen, Mette Terp

2011-01-01

An approach for the solid-phase synthesis of apoptosis-inducing Smac peptidomimetics is presented. Using a Rink linker strategy, tetrapeptides mimicking the N-4-terminal residue of the Smac protein [(N-Me)AVPF sequence] were synthesized on PEGA resin in excellent purities and yields. Following two...

Subaortic membrane mimicking hypertrophic cardiomyopathy.

Science.gov (United States)

Anderson, Mark Joseph; Arruda-Olson, Adelaide; Gersh, Bernard; Geske, Jeffrey

2015-11-04

A 34-year-old man was referred for progressive angina and exertional dyspnoea refractory to medical therapy, with a presumptive diagnosis of hypertrophic cardiomyopathy (HCM). Transthoracic echocardiography (TTE) revealed asymmetric septal hypertrophy without systolic anterior motion of the mitral valve leaflet and with no dynamic left ventricular outflow tract (LVOT) obstruction. However, the LVOT velocity was elevated at rest as well as with provocation, without the characteristic late peaking obstruction seen in HCM. Focused TTE to evaluate for suspected fixed obstruction demonstrated a subaortic membrane 2.2 cm below the aortic valve. Coronary CT angiography confirmed the presence of the subaortic membrane and was negative for concomitant coronary artery disease. Surgical resection of the subaortic membrane and septal myectomy resulted in significant symptomatic relief and lower LVOT velocities on postoperative TTE. This case reminds the clinician to carefully evaluate for alternative causes of LVOT obstruction, especially subaortic membrane, as a cause of symptoms mimicking HCM. 2015 BMJ Publishing Group Ltd.

Odontogenic Keratocyst Mimicking Paradental Cyst

Directory of Open Access Journals (Sweden)

Andrea Enrico Borgonovo

2014-01-01