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Sample records for acoustic ducts

  1. Acoustic Response of a Sinusoidally Perturbed Hard-Walled Duct

    Silvio Del Giudice; Giancarlo Bernasconi

    2013-01-01

    Acoustic wave propagation in hard-walled ducts is of interest in many fields including vehicle design, musical instruments acoustics, and architectural and environmental noise-control. For the case of small sinusoidal perturbation of the cross-section, it is possible to derive simple though approximate analytical formulas of its plane wave acoustic reflection and transmission spectral response that resembles the optical situation of uniform Bragg gratings. The proof is given here, starting fr...

  2. Acoustic Response of a Sinusoidally Perturbed Hard-Walled Duct

    Silvio Del Giudice

    2013-01-01

    Full Text Available Acoustic wave propagation in hard-walled ducts is of interest in many fields including vehicle design, musical instruments acoustics, and architectural and environmental noise-control. For the case of small sinusoidal perturbation of the cross-section, it is possible to derive simple though approximate analytical formulas of its plane wave acoustic reflection and transmission spectral response that resembles the optical situation of uniform Bragg gratings. The proof is given here, starting from the “horn equation” and then exploiting the coupled-modes theory. Examples of the results obtained with these analytical formulas are shown for some sinusoidally perturbed ducts and compared to results obtained through a numerical method, revealing a very good agreement.

  3. Studies of flow duct acoustics with applications to turbocharged engines

    Rämmal, Hans

    2009-01-01

    A number of experimental and theoretical studies, performed in the field of technical flow duct acoustics are presented in this thesis. The acoustical methods treated are implemented on turbocharged IC-engines and engine gas exchange system components. A new method based on the well-known two-load technique has been developed. The method was applied to characterise the source data of various piston-engines with non-linear behaviour including a 6 cylinder turbo-charged truck diesel engine. The...

  4. Duct wall impedance control as an advanced concept for acoustic impression

    Dean, P. D.; Tester, B. J.

    1975-01-01

    Models and tests on an acoustic duct liner system which has the property of controlled-variable acoustic impedance are described. This is achieved by a novel concept which uses the effect of steady air flow through a multi-layer, locally reacting, resonant-cavity absorber. The scope of this work was limited to a 'proof of concept.' The test of the concept was implemented by means of a small-scale, square-section flow duct facility designed specifically for acoustic measurements, with one side of the duct acoustically lined. The test liners were designed with the aid of previously established duct acoustic theory and a semi-empirical impedance model of the liner system. Over the limited range tested, the liner behaved primarily as predicted, exhibiting significant changes in resistance and reactance, thus providing the necessary concept validation.

  5. Development of Adaptive Acoustic Impedance Control Technologies of Acoustic Duct Liner

    Hiroshi Kobayashi

    2011-01-01

    Full Text Available This paper describes the development of adaptive acoustic impedance control (AAC technologies to achieve a larger fan noise reduction, by adaptively adjusting reactance and resistance of the acoustic liner impedance. For the actual proof of the AAC technology III performance, the advanced fan noise absorption control duct liner II was made on trial basis, with the simple control system and the plain device. And, then, the duct liner II was examined for the AAC technology I, II, and III models, using the high speed fan test facility. The test results made clear that the duct liner II of the AAC technology III model could achieve the fan noise reduction higher than O.A. SPL 10 dB (A at the maximum fan speed 6000 rpm, containing the reduction of fundamental BPF tone of 18 dB and 2nd BPF tone of 10 dB in response to the fan peed change from 3000 to 6000 rpm.

  6. A difference theory for noise propagation in an acoustically lined duct with mean flow.

    Baumeister, K. J.; Rice, E. J.

    1973-01-01

    A finite difference formulation is presented for sound propagation in a two-dimensional straight soft-walled duct with uniform flow. The difference analysis is developed in terms of complex notation. The governing acoustic difference equations and the appropriate displacement boundary conditions associated with uniform flow are presented. Example calculations are presented for the sound attenuation in straight hard and soft-walled ducts. At present the finite Mach number case is solved only for the one-dimensional hard walled duct.

  7. Acoustics flow analysis in circular duct using sound intensity and dynamic mode decomposition

    Sound intensity generation in hard-walled duct with acoustic flow (no mean-flow) is treated experimentally and shown graphically. In paper, numerous methods of visualization illustrating the vortex flow (2D, 3D) can graphically explain diffraction and scattering phenomena occurring inside the duct and around open end area. Sound intensity investigation in annular duct gives a physical picture of sound waves in any duct mode. In the paper, modal energy analysis are discussed with particular reference to acoustics acoustic orthogonal decomposition (AOD). The image of sound intensity fields before and above 'cut-off' frequency region are found to compare acoustic modes which might resonate in duct. The experimental results show also the effects of axial and swirling flow. However acoustic field is extremely complicated, because pressures in non-propagating (cut-off) modes cooperate with the particle velocities in propagating modes, and vice versa. Measurement in cylindrical duct demonstrates also the cut-off phenomenon and the effect of reflection from open end. The aim of experimental study was to obtain information on low Mach number flows in ducts in order to improve physical understanding and validate theoretical CFD and CAA models that still may be improved.

  8. Acoustic imaging of a duct spinning mode by the use of an in-duct circular microphone array.

    Wei, Qingkai; Huang, Xun; Peers, Edward

    2013-06-01

    An imaging method of acoustic spinning modes propagating within a circular duct simply with surface pressure information is introduced in this paper. The proposed method is developed in a theoretical way and is demonstrated by a numerical simulation case. Nowadays, the measurements within a duct have to be conducted using in-duct microphone array, which is unable to provide information of complete acoustic solutions across the test section. The proposed method can estimate immeasurable information by forming a so-called observer. The fundamental idea behind the testing method was originally developed in control theory for ordinary differential equations. Spinning mode propagation, however, is formulated in partial differential equations. A finite difference technique is used to reduce the associated partial differential equations to a classical form in control. The observer method can thereafter be applied straightforwardly. The algorithm is recursive and, thus, could be operated in real-time. A numerical simulation for a straight circular duct is conducted. The acoustic solutions on the test section can be reconstructed with good agreement to analytical solutions. The results suggest the potential and applications of the proposed method. PMID:23742352

  9. Numerical techniques in linear duct acoustics - A status report

    Baumeister, K. J.

    1980-01-01

    A review is presented covering both finite difference and finite element analysis of small amplitude (linear) sound propagation in straight and variable area ducts with flow, as might be found in a typical turbojet engine duct, muffer, or industrial ventilation system. Both 'steady' state and transient theories are discussed. Emphasis is placed on the advantages and limitations associated with the various numerical techniques. Examples of practical problems are given for which the numerical techniques have been applied.

  10. Periodic Time-Domain Nonlocal Nonreflecting Boundary Conditions for Duct Acoustics

    Watson, Willie R.; Zorumski, William E.

    1996-01-01

    Periodic time-domain boundary conditions are formulated for direct numerical simulation of acoustic waves in ducts without flow. Well-developed frequency-domain boundary conditions are transformed into the time domain. The formulation is presented here in one space dimension and time; however, this formulation has an advantage in that its extension to variable-area, higher dimensional, and acoustically treated ducts is rigorous and straightforward. The boundary condition simulates a nonreflecting wave field in an infinite uniform duct and is implemented by impulse-response operators that are applied at the boundary of the computational domain. These operators are generated by convolution integrals of the corresponding frequency-domain operators. The acoustic solution is obtained by advancing the Euler equations to a periodic state with the MacCormack scheme. The MacCormack scheme utilizes the boundary condition to limit the computational space and preserve the radiation boundary condition. The success of the boundary condition is attributed to the fact that it is nonreflecting to periodic acoustic waves. In addition, transient waves can pass rapidly out of the solution domain. The boundary condition is tested for a pure tone and a multitone source in a linear setting. The effects of various initial conditions are assessed. Computational solutions with the boundary condition are consistent with the known solutions for nonreflecting wave fields in an infinite uniform duct.

  11. Transmission of wave energy in curved ducts. [acoustic propagation within rigid walls

    Rostafinski, W.

    1974-01-01

    Investigation of the ability of circular bends to transmit acoustic energy flux. A formulation of wave-energy flow is developed for motion in curved ducts. A parametric study over a range of frequencies shows the ability of circular bends to transmit energy in the case of perfectly rigid walls.

  12. Acoustic transmission matrix of a variable area duct or nozzle carrying a compressible subsonic flow

    Miles, J. H.

    1980-01-01

    The differential equations governing the propagation of sound in a variable area duct or nozzle carrying a one-dimensional subsonic compressible fluid flow are derived and put in state variable form using acoustic pressure and particle velocity as the state variables. The duct or nozzle is divided into a number of regions. The region size is selected so that in each region the Mach number can be assumed constant and the area variation can be approximated by an exponential area variation. Consequently, the state variable equation in each region has constant coefficients. The transmission matrix for each region is obtained by solving the constant coefficient acoustic state variable differential equation. The transmission matrix for the duct or nozzle is the product of the individual transmission matrices of each region. Solutions are presented for several geometries with and without mean flow.

  13. High accuracy acoustic relative humidity measurement in duct flow with air

    Cees van der Geld; Twan Wernaart; Mart Grooten; Wilhelm van Schaik

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temp...

  14. Indirect calibration of a large microphone array for in-duct acoustic measurements

    Leclère, Q.; Pereira, A.; Finez, A.; Souchotte, P.

    2016-08-01

    This paper addresses the problem of in situ calibration of a pin hole-mounted microphone array for in-duct acoustic measurements. One approach is to individually measure the frequency response of each microphone, by submitting the probe to be calibrated and a reference microphone to the same pressure field. Although simple, this task may be very time consuming for large microphone arrays and eventually suffer from lack of access to microphones once they are installed on the test bench. An alternative global calibration procedure is thus proposed in this paper. The approach is based on the fact that the acoustic pressure can be expanded onto an analytically known spatial basis. A projection operator is defined allowing the projection of measurements onto the duct modal basis. The main assumption of the method is that the residual resulting from the difference between actual and projected measurements is mainly dominated by calibration errors. An iterative procedure to estimate the calibration factors of each microphone is proposed and validated through an experimental set-up. In addition, it is shown that the proposed scheme allows an optimization of physical parameters such as the sound speed and parameters associated to the test bench itself, such as the duct radius or the termination reflection coefficient.

  15. On waves in gases. Part I: Acoustics of jets, turbulence, and ducts

    Campos, L. M. B. C.

    1986-01-01

    This review on some aspects of waves in gases concentrates first (Part I) on modern research in the acoustics of fluids at rest or in steady or turbulent motion, in free space, in the presence of obstacles, or in ducts. The study of sound, for which the sole restoring force is pressure, will be extended in a later paper (Part II) to include the other three restoring forces, namely, gravity, electromagnetic, and Coriolis forces, leading to current research on internal, magnetic, and inertial waves and their couplings. The Introduction at the beginning of Part I, and the discussion at the end of Part II, concern all four types of waves in gases, and their relevance in physics and engineering. In Part I, the following areas of acoustics are addressed: the generation of noise by turbulence, inhomogeneities or bubbles, in natural and engineering flows, e.g., wind or jets; the scattering of sound by interfaces and diffraction by turbulence, and their effects on spectral and directional redistribution of energy; propagation in ducts, without or with mean flow, e.g., the horns of musical instruments and loudspeakers, and inlets and exhausts of engines; the effects of dissipation and nonlinearity on waves, e.g., in laboratory and engineering shock tubes, and in geophysical and astrophysical conditions. Underlying these topics is the interaction of acoustics with manking, ranging from the processes of human hearing and speech to the reproduction of desirable sounds (music) and reduction of undesirable sounds (noise).

  16. Influence of exit impedance on finite difference solutions of transient acoustic mode propagation in ducts

    Baumeister, K. J.

    1981-01-01

    The cutoff mode instability problem associated with a transient finite difference solution to the wave equation is explained. The steady-state impedance boundary condition is found to produce acoustic reflections during the initial transient, which cause finite instabilities in the cutoff modes. The stability problem is resolved by extending the duct length to prevent transient reflections. Numerical calculations are presented at forcing frequencies above, below, and nearly at the cutoff frequency, and exit impedance models are presented for use in the practical design of turbofan inlets.

  17. Global modes, receptivity, and sensitivity analysis of diffusion flames coupled with duct acoustics

    Magri, Luca

    2014-01-01

    In this theoretical and numerical paper, we derive the adjoint equations for a thermo-acoustic system consisting of an infinite-rate chemistry diffusion flame coupled with duct acoustics. We then calculate the thermo-acoustic system's linear global modes (i.e. the frequency/growth rate of oscillations, together with their mode shapes), and the global modes' receptivity to species injection, sensitivity to base-state perturbations, and structural sensitivity to advective-velocity perturbations. We then compare these with the Rayleigh index. The receptivity analysis shows the regions of the flame where open-loop injection of fuel or oxidizer will have most influence on the thermo-acoustic oscillation. We find that the flame is most receptive at its tip. The base-state sensitivity analysis shows the influence of each parameter on the frequency/growth rate. We find that perturbations to the stoichiometric mixture fraction, the fuel slot width, and the heat-release parameter have most influence, while perturbation...

  18. High accuracy acoustic relative humidity measurement in duct flow with air.

    van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments. PMID:22163610

  19. High Accuracy Acoustic Relative Humidity Measurement inDuct Flow with Air

    Cees van der Geld

    2010-08-01

    Full Text Available An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temperature 0–100 °C with an error of ±0.07 °C and relative humidity 0–100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.

  20. Concurrent identification of aero-acoustic scattering and noise sources at a flow duct singularity in low Mach number flow

    Sovardi, Carlo; Jaensch, Stefan; Polifke, Wolfgang

    2016-09-01

    A numerical method to concurrently characterize both aeroacoustic scattering and noise sources at a duct singularity is presented. This approach combines Large Eddy Simulation (LES) with techniques of System Identification (SI): In a first step, a highly resolved LES with external broadband acoustic excitation is carried out. Subsequently, time series data extracted from the LES are post-processed by means of SI to model both acoustic propagation and noise generation. The present work studies the aero-acoustic characteristics of an orifice placed in a duct at low flow Mach numbers with the "LES-SI" method. Parametric SI based on the Box-Jenkins mathematical structure is employed, with a prediction error approach that utilizes correlation analysis of the output residuals to avoid overfitting. Uncertainties of model parameters due to the finite length of times series are quantified in terms of confidence intervals. Numerical results for acoustic scattering matrices and power spectral densities of broad-band noise are validated against experimental measurements over a wide range of frequencies below the cut-off frequency of the duct.

  1. Adjoint problem in duct acoustics and its reciprocity to forward problem by the Time Domain Wave Packet method

    Kocaogul, Ibrahim; Hu, Fang; Li, Xiaodong

    2014-03-01

    Radiation of acoustic waves at all frequencies can be obtained by Time Domain Wave Packet (TDWP) method in a single time domain computation. Other benefit of the TDWP method is that it makes possible the separation of acoustic and instability wave in the shear flow. The TDWP method is also particularly useful for computations in the ducted or waveguide environments where incident wave modes can be imposed cleanly without a potentially long transient period. The adjoint equations for the linearized Euler equations are formulated for the Cartesian coordinates. Analytical solution for adjoint equations is derived by using Green's function in 2D and 3D. The derivation of reciprocal relations is presented for closed and open ducts. The adjoint equations are then solved numerically in reversed time by the TDWP method. Reciprocal relation between the duct mode amplitudes and far field point sources in the presence of the exhaust shear flow is computed and confirmed numerically. Applications of the adjoint problem to closed and open ducts are also presented.

  2. Identification of acoustic wave propagation in a duct line and its application to detection of impact source location based on signal processing

    For the detection of the impact location in a pipeline system, the correlation method has been the conventional method. For the application of the correlation method, the diameter of a duct should be small so that the acoustic wave inside the duct can propagate with nondispersive characteristics, in the form of, for example, a plane wave. This correlation method calculates the cross-correlation between acoustic waves measured at two acceleration sensors attached to a buried duct. It also gives information about the arrival time delay of an acoustic wave between two sensors. These arrival time delays are used for the estimation of the impact location. However, when the diameter of the duct is large, the acoustic waves inside the duct propagate with dispersive characteristics owing to the reflection of the acoustic wave off of the wall of the duct. This dispersive characteristic is related to the acoustic modes inside a duct. Therefore, the correlation method does not work correctly for the detection of the impact location. This paper proposes new methods of accurately measuring the arrival time delay between two sensors attached to duct line system. This method is based on the time-frequency analyses of the short time Fourier transform (STFT) and continuous wavelet transform (CWT). These methods can discriminate direct waves (non-dispersive waves) and reflective waves (dispersive waves) from the measured wave signals through the time-frequency analysis. The direct wave or the reflective wave is used to estimate the arrival time delay. This delay is used for the identification of the impact location. This systematic method can predict the impact location due to the impact forces of construction equipment with more accuracy than the correlation method

  3. Identification of acoustic wave propagation in a duct line and its application to detection of impact source location based on signal processing

    Shin, Yong Woo; Kim, Min Soo; Lee, Sang Kwon [Inha University, Seoul (Korea, Republic of)

    2010-12-15

    For the detection of the impact location in a pipeline system, the correlation method has been the conventional method. For the application of the correlation method, the diameter of a duct should be small so that the acoustic wave inside the duct can propagate with nondispersive characteristics, in the form of, for example, a plane wave. This correlation method calculates the cross-correlation between acoustic waves measured at two acceleration sensors attached to a buried duct. It also gives information about the arrival time delay of an acoustic wave between two sensors. These arrival time delays are used for the estimation of the impact location. However, when the diameter of the duct is large, the acoustic waves inside the duct propagate with dispersive characteristics owing to the reflection of the acoustic wave off of the wall of the duct. This dispersive characteristic is related to the acoustic modes inside a duct. Therefore, the correlation method does not work correctly for the detection of the impact location. This paper proposes new methods of accurately measuring the arrival time delay between two sensors attached to duct line system. This method is based on the time-frequency analyses of the short time Fourier transform (STFT) and continuous wavelet transform (CWT). These methods can discriminate direct waves (non-dispersive waves) and reflective waves (dispersive waves) from the measured wave signals through the time-frequency analysis. The direct wave or the reflective wave is used to estimate the arrival time delay. This delay is used for the identification of the impact location. This systematic method can predict the impact location due to the impact forces of construction equipment with more accuracy than the correlation method

  4. Numerical spatial marching techniques in duct acoustics. [noise source calculation from far field pressure measurements

    Baumeister, K. J.

    1979-01-01

    Direct calculation of the internal structure of a ducted noise source from farfield pressure measurements is regarded as an initial value problem, where the pressure and pressure gradient (farfield impedance) are assumed to be known along a line in the farfield. If pressure and impedance are known at the boundary of the farfield, the pressure can be uniquely determined in the vicinity of the inlet and inside the inlet ducting. A marching procedure is developed which, with this information obtained from measurements, enables a description of a ducted noise source. The technique uses a finite difference representation of the homogeneous Helmholtz equation.

  5. Numerical techniques in linear duct acoustics. [finite difference and finite element analyses

    Baumeister, K. J.

    1980-01-01

    Both finite difference and finite element analyses of small amplitude (linear) sound propagation in straight and variable area ducts with flow, as might be found in a typical turboject engine duct, muffler, or industrial ventilation system, are reviewed. Both steady state and transient theories are discussed. Emphasis is placed on the advantages and limitations associated with the various numerical techniques. Examples of practical problems are given for which the numerical techniques have been applied.

  6. Applications of velocity potential function to acoustic duct propagation and radiation from inlets using finite element theory

    Baumeister, K. J.; Majjigi, R. K.

    1979-01-01

    A finite element velocity potential program has been developed to study acoustic wave propagation in complex geometries. For irrotational flows, relatively low sound frequencies, and plane wave input, the finite element solutions show significant effects of inlet curvature and flow gradients on the attenuation of a given acoustic liner in a realistic variable area turbofan inlet. In addition, as shown in the paper, the velocity potential approach can not be used to estimate the effects of rotational flow on acoustic propagation since the potential acoustic disturbances propagate at the speed of the media in sheared flow. Approaches are discussed that are being considered for extending the finite element solution to include the far field as well as the internal portion of the duct. A new matrix partitioning approach is presented that can be incorporated in previously developed programs to allow the finite element calculation to be marched into the far field. The partitioning approach provides a large reduction in computer storage and running times.

  7. Active Control of Fan Noise: Feasibility Study. Volume 5; Numerical Computation of Acoustic Mode Reflection Coefficients for an Unflanged Cylindrical Duct

    Kraft, R. E.

    1996-01-01

    A computational method to predict modal reflection coefficients in cylindrical ducts has been developed based on the work of Homicz, Lordi, and Rehm, which uses the Wiener-Hopf method to account for the boundary conditions at the termination of a thin cylindrical pipe. The purpose of this study is to develop a computational routine to predict the reflection coefficients of higher order acoustic modes impinging on the unflanged termination of a cylindrical duct. This effort was conducted wider Task Order 5 of the NASA Lewis LET Program, Active Noise Control of aircraft Engines: Feasibility Study, and will be used as part of the development of an integrated source noise, acoustic propagation, ANC actuator coupling, and control system algorithm simulation. The reflection coefficient prediction will be incorporated into an existing cylindrical duct modal analysis to account for the reflection of modes from the duct termination. This will provide a more accurate, rapid computation design tool for evaluating the effect of reflected waves on active noise control systems mounted in the duct, as well as providing a tool for the design of acoustic treatment in inlet ducts. As an active noise control system design tool, the method can be used preliminary to more accurate but more numerically intensive acoustic propagation models such as finite element methods. The resulting computer program has been shown to give reasonable results, some examples of which are presented. Reliable data to use for comparison is scarce, so complete checkout is difficult, and further checkout is needed over a wider range of system parameters. In future efforts the method will be adapted as a subroutine to the GEAE segmented cylindrical duct modal analysis program.

  8. Inverse estimation of the temperature field within a gas-filled duct section by use of acoustic data

    Knowledge of the temperature distribution of an in-duct gaseous medium is essential in the monitoring of combustion status. To obtain the temperature distribution, an inverse relationship based on the Radon transform is formulated by using the measured time retardation data from a set of acoustic sensors and actuators. The entire spatial distribution can be obtained by interpolating the estimated discrete temperature data using either a path-based or spaced-based method. An interpolation method then determines the precision of the final imaging result. The characteristics and performance of two interpolation methods are investigated in a simulation study by reconstructing the temperature distribution of a rectangular cross-section. To calculate the temperature field, the path-based interpolation method adopts a direct expression of temperature variation along the propagation path, whereas the space-based interpolation method uses data obtained at predetermined points deployed inside the field. The average reconstruction accuracy of the space-based interpolation for temperature fields with 1 and 4 local maxima is 22% and 183% better than that of path-based interpolation, respectively. Also, the space-based interpolation method is more robust with regard to measurement noise than the path-based interpolation method. (paper)

  9. Application of dual reciprocity boundary element method for prediction of acoustic characteristics of ducts and silencers with three-dimensional potential flow

    WANG Xueren; JI Zhenlin

    2008-01-01

    The Dual Reciprocity Boundary Element Method(DRBEM)is applied to predict the acoustic characteristics of ducts and silencers with three-dimensional potential flow,and the basic principle and numerical procedure of the proposed method are introduced.Compared to the Conventional Boundary Element Method (CBEM),the DRBEM takes into account the second order terms of flow Mach number in the acoustic governing equation,which is suitable for the situations with higher Mach number subsonic flow.The four-pole parameters of a duct and a varying cross-sectional area expansion chamber are predicted with the DRBEM,and the predictions are compared with the one-dimensional analytical solutions and the CBEM results.The comparisons demonstrated that the present method is valid.Transmission loss of silencers with difierent structures was also calculated with the DRBEM.The results showed that the influence of the three-dimensional flow on the acoustic characteristics of silencers with complex structures is not negligible.

  10. Verification of an acoustic transmission matrix analysis of sound propagation in a variable area duct without flow

    Miles, J. H.

    1981-01-01

    A predicted standing wave pressure and phase angle profile for a hard wall rectangular duct with a region of converging-diverging area variation is compared to published experimental measurements in a study of sound propagation without flow. The factor of 1/2 area variation used is sufficient magnitude to produce large reflections. The prediction is based on a transmission matrix approach developed for the analysis of sound propagation in a variable area duct with and without flow. The agreement between the measured and predicted results is shown to be excellent.

  11. Acoustics

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  12. 海洋混合层结构对表面声道中声传播特性的影响分析%The effect of ocean mixed-layer structure on acoustic propagation in a surface duct environment

    张旭; 张永刚; 张健雪; 董楠

    2012-01-01

    Based on WOA05 climatological database and the measured hydrologic data in the northern Huanghai Sea, the effect of typical mixed-layer structures on the acoustic propagation in a surface duct environment in adjacent sea areas of China is discussed using the BELLHOP Gaussian beam model. The mixed-layer structures show distinct variations between different areas and seasons. In the deep sea, the mixed-layer depth is a main variable factor, which defines the vertical space of the surface duct. A obvious difference of acoustic energe level ? Appears when the propagation occurs in a surface channel inside the mixed-layer compared with that in a shadow zone outside the mixed-layer. In the shallow water, the mixed-layer depth and the sound speed grads are both streaky. More reversal rays are involved when the sound speed grads enhancing or the mixed-layer depth deepening, which make the energe level in the surface duct increased. Two groups of measured data show that the mixed-layer depth may yield or fade suddenly with time and distribute asymmetrically with range. Under a thermocline enviroment in the shallow water, the acoustic energy level near the surface can be evidently raising when the surface duct comes into being in condition of some specific oceanographic phenomena in the air-sea boundary layer.%利用WOA05气候态数据集和北黄海调查数据,应用BELLHOP高斯束射线模型分析了我国近海及西太平洋典型海区的混合层结构对表面声道中声传播特性的影响,结果表明:我国近海的混合层结构有显著的区域性和季节性变化;深海中主要表现为混合层深度变化,这种变化直接影响表面声道的空间分布,声波在混合层中的表面声道中传播与在混合层外的影区中传播产生的能量场差异较大;浅海中混合层深度与声速梯度的空间变化都很明显,声速梯度的增大和混合层的加深都能使更多声线以反转的形式传播,使表面声道声场增强

  13. Application of transmission loss concept in the evaluation of an acoustic filter for liquid-borne transverse resonance modes in a duct of circular cross section

    Iwanicki, L. R.; Chang, Y. M.

    1980-01-01

    The transmission loss concept is used in the evaluation of an acoustic filter for liquid-borne transverse modes. Tests are conducted to determine the nature of filter element designs required to suppress transverse modes, to verify the presence of transverse modes in the test assembly, to define the acoustic wave incident, and to establish data recording, processing and analysis techniques providing transmission wave filter data. The first, second, and third tangential modes, and the first radial mode are found at frequencies of 2150, 3330, 4420, and 4110 Hz, respectively, and peaks of the tangential modes recede while the radial mode peak remains, demonstrating agreement with theoretical nodal patterns. The present design is found applicable to a liquid-oxygen system, and allows the easy-to-fabricate filter to fit within the available space envelope.

  14. Ducted turbine theory with right angled ducts

    This paper describes the use of an inviscid approach to model a ducted turbine – also known as a diffuser augmented turbine – and a comparison of results with a particular one-dimensional theory. The aim of the investigation was to gain a better understanding of the relationship between a real duct and the ideal diffuser, which is a concept that is developed in the theory. A range of right angled ducts, which have a rim for a 90° exit angle, were modelled. As a result, the performance of right angled ducts has been characterised in inviscid flow. It was concluded that right angled ducts cannot match the performance of their associated ideal diffuser and that the optimum rotor loading for these turbines varies with the duct dimensions

  15. Preconditioning the Helmholtz Equation for Rigid Ducts

    Baumeister, Kenneth J.; Kreider, Kevin L.

    1998-01-01

    An innovative hyperbolic preconditioning technique is developed for the numerical solution of the Helmholtz equation which governs acoustic propagation in ducts. Two pseudo-time parameters are used to produce an explicit iterative finite difference scheme. This scheme eliminates the large matrix storage requirements normally associated with numerical solutions to the Helmholtz equation. The solution procedure is very fast when compared to other transient and steady methods. Optimization and an error analysis of the preconditioning factors are present. For validation, the method is applied to sound propagation in a 2D semi-infinite hard wall duct.

  16. Early bile duct cancer

    Jae Myung Cha; Myung-Hwan Kim; Se Jin Jang

    2007-01-01

    Bile duct cancers are frequently diagnosed as advanced diseases. Over half of patients with advanced bile duct cancer present with unresectable malignancies and their prognosis has been very poor even after curative resections. Although there has been a need to diagnose bile duct cancer at its early stage, it has been a difficult goal to achieve due to our lack of knowledge regarding this disease entity. Early bile duct cancer may be defined as a carcinoma whose invasion is confined within the fibromuscular layer of the extrahepatic bile duct or intrahepatic large bile duct without distant metastasis irrespective of lymph node involvement. Approximately 3%-10% of resected bile duct cancers have been reported to be early cancers in the literature. The clinicopathological features of patients with early bile duct cancer differ from those of patients with advanced bile duct cancer, with more frequent asymptomatic presentation, characteristic histopathological findings,and excellent prognosis. This manuscript is organized to emphasize the need for convening an international consensus to develop the concept of early bile duct cancer.

  17. Slow sound in lined flow ducts

    Auregan, Yves

    2015-01-01

    We consider the acoustic propagation in lined flow duct with a purely reactive impedance at the wall. This reacting liner has the capability to reduce the speed of sound, and thus to enhance the interaction between the acoustic propagation and the low Mach number flow ($M\\simeq0.3$). At the lower frequencies, there are typically 4 acoustic or hydrodynamic propagating modes, with 3 of them propagating in the direction of the flow. Above a critical frequency, there are only 2 propagating modes that all propagate in the direction of the flow. From the exact 2D formulation an approximate 1D model is developed to study the scattering of acoustic waves in a straight duct with varying wall impedance. This simple system, with a uniform flow and with a non-uniform liner impedance at the wall, permits to study the scattering between regions with different waves characteristics. Several situations are characterized to show the importance of negative energy waves, strong interactions between acoustic and hydrodynamic mod...

  18. Patent arterial duct

    Martin Robin P; Elmasry Ola A; Forsey Jonathan T

    2009-01-01

    Abstract Patent arterial duct (PAD) is a congenital heart abnormality defined as persistent patency in term infants older than three months. Isolated PAD is found in around 1 in 2000 full term infants. A higher prevalence is found in preterm infants, especially those with low birth weight. The female to male ratio is 2:1. Most patients are asymptomatic when the duct is small. With a moderate-to-large duct, a characteristic continuous heart murmur (loudest in the left upper chest or infraclavi...

  19. Sound Radiation from a Supersonic Jet Passing Through a Partially Open Exhaust Duct

    Kandula, Max

    2011-01-01

    The radiation of sound from a perfectly expanded Mach 2.5 cold supersonic jet of 25.4 mm exit diameter flowing through a partially open rigid-walled duct with an upstream i-deflector has been studied experimentally. In the experiments, the nozzle is mounted vertically, with the nozzle exit plane at a height of 73 jet diameters above ground level. Relative to the nozzle exit plane (NEP), the location of the duct inlet is varied at 10, 5, and -1 jet diameters. Far-field sound pressure levels were obtained at 54 jet diameters above ground with the aid of acoustic sensors equally spaced around a circular arc of radius equal to 80 jet diameters from the jet axis. Data on the jet acoustic field for the partially open duct were obtained and compared with those with a free jet and with a closed duct. The results suggest that for the partially open duct the overall sound pressure level (OASPL) decreases as the distance between the NEP and the duct inlet plane decreases, while the opposite trend is observed for the closed duct. It is also concluded that the observed peak frequency in the partially open duct increases above the free jet value as the angle from the duct axis is increased, and as the duct inlet plane becomes closer to the NEP.

  20. Curved-Duct

    Je Hyun Baekt

    2000-01-01

    Full Text Available A numerical study is conducted on the fully-developed laminar flow of an incompressible viscous fluid in a square duct rotating about a perpendicular axis to the axial direction of the duct. At the straight duct, the rotation produces vortices due to the Coriolis force. Generally two vortex cells are formed and the axial velocity distribution is distorted by the effect of this Coriolis force. When a convective force is weak, two counter-rotating vortices are shown with a quasi-parabolic axial velocity profile for weak rotation rates. As the rotation rate increases, the axial velocity on the vertical centreline of the duct begins to flatten and the location of vorticity center is moved near to wall by the effect of the Coriolis force. When the convective inertia force is strong, a double-vortex secondary flow appears in the transverse planes of the duct for weak rotation rates but as the speed of rotation increases the secondary flow is shown to split into an asymmetric configuration of four counter-rotating vortices. If the rotation rates are increased further, the secondary flow restabilizes to a slightly asymmetric double-vortex configuration. Also, a numerical study is conducted on the laminar flow of an incompressible viscous fluid in a 90°-bend square duct that rotates about axis parallel to the axial direction of the inlet. At a 90°-bend square duct, the feature of flow by the effect of a Coriolis force and a centrifugal force, namely a secondary flow by the centrifugal force in the curved region and the Coriolis force in the downstream region, is shown since the centrifugal force in curved region and the Coriolis force in downstream region are dominant respectively.

  1. Acoustic image typing of thyroglossal duct cyst by high frequency ultrasonography and its diagnosis value%高频超声对甲状舌管囊肿的分型及诊断价值

    叶琴; 林礼务; 薛恩生; 林学英; 何以敉; 吴丽足; 梁荣喜

    2009-01-01

    Objective To probe the clinical diagnosis value of high frequency ultrasonography (HFUS) in thyroglossal duct cyst(TDC). Methods Forty-one TDC were taken HFUS and the location, boundary,shape,interal echo of lesions and the relation to hyoid bone were observed. The periphery and internal blood flow signal were detected by color Doppler flow imaging. The results of HFUS were compared with those of pathology after operation. The cases were divided into groups according to pathological types and were compared with acoustic image shows. Results All cases were diagnosed TDC by pathology after operation. Internal walls of 9 TDC consist of cilium columnar epithelium, 19 consist of stratified pavement epithelium and 13 consist of this two epitheliums. HFUS showed different pathological types had different ultrasonic appearances. In this study, 77.8%(7/9) TDC with columnar epithelium showed echoless,84.2 (16/19) TDC with pavement epithelium showed similar solid echopattern and TDC with two epitheliums mainly showed similar solid echopattern and multi-room cyst. Hyperechogenicity of hyoid bone displayed around the lesion in 80.5%(33/41)TDC. No blood flow signal showed in 41 TDC and a little punctiform blood flow signal showed in the periphery of 5 TDC. The diagnose accordance rate of HFUS in TDC was 95.1%(39/41). Conclusions HFUS can clearly show the location, boundary, shape,interal echo of TDC and its relation to hyoid bone. HFUS is important for diagnosis and differential diagnosis of TDC.%目的 探讨高频超声检查对甲状舌管囊肿(TDC)的临床诊断价值.方法 应用高频超声检查41例TDC,观察病变的位置、边界、形态、内部回声及其与舌骨的关系,并应用彩色多普勒血流显像观察肿物边缘与内部的血流信号.超声检查结果 与手术病理诊断对照,将所有资料按照病理类型分组并分别与声像图表现对比.结果 全部病例均经手术病理证实为TDC,其中9例TDC内衬纤毛柱状上皮,19

  2. Patent arterial duct

    Martin Robin P

    2009-07-01

    Full Text Available Abstract Patent arterial duct (PAD is a congenital heart abnormality defined as persistent patency in term infants older than three months. Isolated PAD is found in around 1 in 2000 full term infants. A higher prevalence is found in preterm infants, especially those with low birth weight. The female to male ratio is 2:1. Most patients are asymptomatic when the duct is small. With a moderate-to-large duct, a characteristic continuous heart murmur (loudest in the left upper chest or infraclavicular area is typical. The precordium may be hyperactive and peripheral pulses are bounding with a wide pulse pressure. Tachycardia, exertional dyspnoea, laboured breathing, fatigue or poor growth are common. Large shunts may lead to failure to thrive, recurrent infection of the upper respiratory tract and congestive heart failure. In the majority of cases of PAD there is no identifiable cause. Persistence of the duct is associated with chromosomal aberrations, asphyxia at birth, birth at high altitude and congenital rubella. Occasional cases are associated with specific genetic defects (trisomy 21 and 18, and the Rubinstein-Taybi and CHARGE syndromes. Familial occurrence of PAD is uncommon and the usual mechanism of inheritance is considered to be polygenic with a recurrence risk of 3%. Rare families with isolated PAD have been described in which the mode of inheritance appears to be dominant or recessive. Familial incidence of PAD has also been linked to Char syndrome, familial thoracic aortic aneurysm/dissection associated with patent arterial duct, and familial patent arterial duct and bicuspid aortic valve associated with hand abnormalities. Diagnosis is based on clinical examination and confirmed with transthoracic echocardiography. Assessment of ductal blood flow can be made using colour flow mapping and pulsed wave Doppler. Antenatal diagnosis is not possible, as PAD is a normal structure during antenatal life. Conditions with signs and symptoms of

  3. THYROGLOSSAL DUCT CYST

    E. Târcoveanu

    2009-02-01

    Full Text Available The thyroglossal duct cyst (TDC results from a failure in obliterating the embryogenic duct produced during thyroid migration and it represents the most common type of developmental cyst encountered in the neck region. Ectopic thyroid tissue neoplasias are rare, and even rarer when associated with the TDC. Methods: During the period 1998-2008, in the First Surgical Clinic, University Hospital “St. Spiridon” Iasi, 14 patients with thyroglossal duct cyst were diagnosed and treated. All records were reviewed for age and sex, diagnostic methods, sizes, surgical management and recurrences. Results: All patients with thyroglossal duct cysts are described as midline cysts of the neck. The ratio females/males was 6/1 with mean age 37.6 years (13-60 years. One case was with an external fistula. The treatment performed was a variant of Sistrunk’s procedure in which the thyroglossal tract was excised to a variable extent, but in all cases with central hyoidectomy. The size of the cyst ranged from 1.2 to 4 cm (mean 2.6 cm. Postoperative course was unventful in all cases. No recurrence was recorded in this series. We describe a case, a 19 years old female with thyroid papillary carcinoma evolving from a TDC. The literature is reviewed. Conclusion: The standard surgical approach to TDC is Sistrunk's operation with low recurrence rates. Malignancy within a thyroglossal duct cyst is very rare but should be included in the differential diagnosis of a neck mass. In such cases total thyroidectomy with removal of the tumour of thyroglossal duct and the body of the hyoid bone are recommended – because the carcinoma may be multifocal and because a lymphatic invasion of the thyroid may take place – in order to ensure a correct follow-up.

  4. Particle deposition in ventilation ducts

    Sippola, Mark R.

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 {micro}m were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on

  5. Application of finite difference techniques to noise propagation in jet engine ducts

    Baumeister, K. J.

    1973-01-01

    A finite difference formulation is presented for wave propagation in a rectangular two-dimensional duct without steady flow. The difference technique, which should be used in the study of acoustically treated inlet and exhausts ducts used in turbofan engines, can readily handle acoustical flow field complications such as axial variations in wall impedance and cross-section area. In the numerical analysis, the continuous acoustic field is lumped into a series of grid points in which the pressure and velocity at each grid point are separated into real and imaginary terms. An example calculation is also presented for the sound attenuation in a two-dimensional straight soft-walled suppressor.

  6. Time dependent difference theory for sound propagation in axisymmetric ducts with plug flow

    Baumeister, K. J.

    1980-01-01

    The time dependent governing/acoustic-difference equations and boundary conditions are developed and solved for sound propagation in an axisymmetric (cylindrical) hard wall duct with a plug mean flow and spinning acoustic modes. The analysis begins with a harmonic sound source radiating into a quiescent duct. This explicit iteration method then calculates stepwise in real time to obtain the transient as well as the 'steady' state solutions of the acoustic field. The time dependent finite difference analysis has two advantages over the steady state finite difference and finite element techniques: (1) the elimination of large matrix storage requirements, and (2) shorter solution times under most conditions.

  7. Application of finite difference techniques to noise propagation in jet engine ducts

    Baumeister, K. J.

    1973-01-01

    A finite difference formulation is presented for wave propagation in a rectangular two-dimensional duct without steady flow. The difference technique, which should be useful in the study of acoustically treated inlet and exhausts ducts used in turbofan engines, can readily handle acoustical flow field complications such as axial variations in wall impedance and cross section area. In the numerical analysis, the continuous acoustic field is lumped into a series of grid points in which the pressure and velocity at each grid point are separated into real and imaginary terms. An example calculation is also presented for the sound attenuation in a two-dimensional straight soft-walled suppressor.

  8. Gallblader and bile duct

    2009-01-01

    2009215 Construction of the specific MUC5AC-siRNA expression plasmid and effect of siRNA on proliferation and apoptosis in human bile duct cancer line HCCC-9810.HUANG Qing(黄强),et al.Dept General Surg,Affili Prov Hosp,Anhui Med Univ,Hefei 230001.World Chin J Digestol.2009;17(6):566-572.

  9. Magnetohydrodynamics in rectangular ducts

    Magnetohydrodynamic flow in straight ducts or bends is a key issue, which has to be investigated for developing self-cooled liquid metal blankets of fusion reactors. The code presented solves the full set of governing equations and simulates all phenomena of such flows, including inertial effects. The range of application is limited by computer storage only. (orig./WL)

  10. Duct Leakage Repeatability Testing

    Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques for duct leakage using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards. The three duct leak measurement methods assessed in this report are the two duct pressurization methods that are commonly used by many practitioners and the DeltaQ technique. These are methods B, C and A, respectively of the ASTM E1554 standard. Although it would be useful to evaluate other duct leak test methods, this study focused on those test methods that are commonly used and are required in various test standards, such as BPI (2010), RESNET (2014), ASHRAE 62.2 (2013), California Title 24 (CEC 2012), DOE Weatherization and many other energy efficiency programs.

  11. Design Optimization of Propeller Duct

    Aasebø, Steinar Martin

    2009-01-01

    This Master Thesis ends up in a design optimization of a propeller duct profile as an example of multi-objective optimization with computationally expensive objective function evaluation. Computational Fluid Dynamics simulation of the ducted propeller is then done as objective evaluation. Response surface methods are employed in the propeller duct profile optimization.

  12. Compressive sensing based spinning mode detections by in-duct microphone arrays

    Yu, Wenjun; Huang, Xun

    2016-05-01

    This paper presents a compressive sensing based experimental method for detecting spinning modes of sound waves propagating inside a cylindrical duct system. This method requires fewer dynamic pressure sensors than the number required by the Shannon–Nyquist sampling theorem so long as the incident waves are sparse in spinning modes. In this work, the proposed new method is firstly validated by preparing some of the numerical simulations with representative set-ups. Then, a duct acoustic testing rig with a spinning mode synthesiser and an in-duct microphone array is built to experimentally demonstrate the new approach. Both the numerical simulations and the experiment results are satisfactory, even when the practical issue of the background noise pollution is taken into account. The approach is beneficial for sensory array tests of silent aeroengines in particular and some other engineering systems with duct acoustics in general.

  13. Rare bile duct anomaly: B3 duct draining to gallbladder

    Seung Eun Lee

    2016-01-01

    Full Text Available A 10-year-old girl presented with recurrent right upper abdominal pain and dyspepsia. Magnetic resonance cholangiopancreatography revealed a dilated common channel of intrahepatic bile duct of segment 3 (B3 and segment 4 (B4 drained into the gallbladder directly. The patient underwent laparoscopic cholecystectomy and Roux-en Y hepaticojejunostomy (B3-jejunostomy. Among the anatomical variability of the biliary system, the cholecystohepatic ducts are controversial in existence and incidence. We report a very rare variant of a cholecystohepatic duct in which the B3 duct drained into gallbladder directly and to the best of our knowledge this is the first report.

  14. Bile duct malignancies.

    Tucek, S; Tomasek, J; Halámkova, J; Kiss, I; Andrasina, T; Hemmelová, B; Adámková-Krákorová, D; Vyzula, R

    2010-01-01

    Bile duct malignancies include intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma (ECC), gall bladder carcinoma (GC) and carcinoma of Vater's ampulla (ampulloma). Bile duct neoplasms are rare tumours with overall poor prognosis. The overall incidence affects up to 12.5 per 100,000 persons in the Czech Republic. The mortality rate has risen recently to 9.5 per 100,000 persons. The incidence and mortality have been remarkably stable over the past 3 decades. The survival rate of patients with these tumours is poor, usually not exceeding 12 months. The diagnostic process is complex, uneasy and usually late. Most cases are diagnosed when unresectable, and palliative treatment is the main approach of medical care for these tumours. The treatment remains very challenging. New approaches have not brought much improvement in this field. Standards of palliative care are lacking and quality of life assessments are surprisingly not common. From the scarce data it seems, however, that multimodal individually tailored treatment can prolong patients'survival and improve the health-related quality of life. The care in specialized centres offers methods of surgery, interventional radiology, clinical oncology and high quality supportive care. These methods are discussed in the article in greater detail. Improvements in this field can be sought in new diagnostic methods and new procedures in surgery and interventional radiology. Understanding the tumour biology on the molecular level could shift the strategy to a more successful one, resulting in more cured patients. Further improvements in palliative care can be sought by defining new targets and new drug development. The lack of patients with bile duct neoplasms has been the limiting factor for any improvements. A new design of larger randomized international multicentric clinical trials with prompt data sharing could help to overcome this major problem. Defining standards of palliative care is a necessity

  15. Gallbladder and bile duct

    1993-01-01

    930559 An experimental study on effective hep-atic blood flow and hepatic energy metabolismfollowing acute obstructive cholangitis and bil-iary obstruction.SUN Wenbing (孙文兵),et al.Hepatobili Surg,Center,Southwest Hosp,Chongqing 630000.Chin J Digest 1992;12(5):261—263.The changes of effective hepatic blood flow(E-HBF)and hepatic energy metabolism were stud-ied following acutc obstructive cholangitis(AOC)and bile duct ligation(BDL)in rats.The resultsshowed that EHBF was significantly decreased at24hs after and further decreased at 48hs afterBDL.And EHBF was significantly decreased at

  16. Duct Remediation Program

    The Duct Remediation Program was established in March of 1990 to identify and remediate sections of plutonium contaminated ductwork in existing Plutonium Fabrication and Recovery Facilities at Rocky Flats near Golden, Colorado. The program was implemented as a result of non-destructive assay measurements which identified areas of significant holdup accumulations. These facilities housed plutonium operations for over 30 years and included processes such as foundries, machining, and plutonium transfer/storage. The Secretary of Energy defined the criteria for remediation success as ''...as low as practicable, but in no case greater than 400 grams of plutonium in any single upward flow path in a glovebox exhaust system...'' This criteria was additionally restricted to include a non-destructive measurement uncertainty of 100 percent. The remediation project also had to comply with the Defense Nuclear Facility Safety Board (DNFSB) Recommendation 90-6. The ''As Low As Practicable'' criteria became the programmatic goal and the basis of the research and operation that occurred over a two year period. Department of Energy (DOE) Orders provided design and safety criteria bounding the engineering methods used in program development. A Mockup and Test Facility was established for the conception and refinement of holdup material characterization, tool manipulation, remediation equipment, duct access, and operational procedures. With these items in place the remediation operation was implemented and carried through to completion

  17. Propagation of sound waves in ducts

    Jacobsen, Finn

    2000-01-01

    Plane wave propagation in ducts with rigid walls, radiation from ducts, classical four-pole theory for composite duct systems, and three-dimentional waves in wave guides of various cross-sectional shape are described.......Plane wave propagation in ducts with rigid walls, radiation from ducts, classical four-pole theory for composite duct systems, and three-dimentional waves in wave guides of various cross-sectional shape are described....

  18. Ascariasis of the pancreatic duct.

    Klimovskij, Michail; Dulskas, Audrius; Kraulyte, Zita; Mikalauskas, Saulius

    2015-01-01

    Ascariasis is a common helminthic disease worldwide, although Lithuania and other European countries are not considered endemic areas. The presence of the Ascaris worm in the biliary tree causes choledocholithiasis-like symptoms. We report a case of pancreatic duct ascariasis causing such symptoms. A 73-year-old Lithuanian woman underwent endoscopic retrograde cholangiopancreatography (ERCP) suspecting choledocholithiasis. Contrast injection into the common bile duct demonstrated a slightly dilated biliary tree without any filling defects, and the tail of an Ascaris worm protruding from the opening of the papilla Vater. The worm was captured by a snare but escaped deep into the duct. After a small wirsungotomy the worm was retrieved from the pancreatic duct. The patient received a 150 mg dose of levamisole orally repeated 7 days later and was discharged after complete resolution of symptoms. This first reported sporadic case of pancreatic duct ascariasis in Lithuania was successfully treated with ERCP and Levamisole. PMID:26374772

  19. Lecture Notes On Acoustics

    This book mentions string vibration and wave, one-dimension wave and wave equation, characteristic impedance, governing equation of string, and wave energy from string, wave equation of wave and basic physical quantity like one-dimension wave equation, sound unit, sound intensity and energy, sound movement in a surface of discontinuity with transmission loss of sound by partition, and Snell's law, radiation, scatter and diffraction and sound in closed space with Sabine's theory, sound characteristic of closed space and duct acoustics.

  20. Ground duct ventilation in greenhouses

    Riera Sayol, Guiu

    2014-01-01

    A greenhouse climate control system is simulated in MATLAB and Simulink. The model calculates for every 20 minutes the temperatures and energy consumption over a whole year. Ground ducts are used in order to save energy which is stored in the ground when there is an excess of heat during the day. This energy is used when the temperature is not high enough, generally in the early morning. Additionally, the ground ducts reduce the usage of windows, due to better dehumidification and...

  1. Duct Leakage Repeatability Testing

    Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-01-01

    Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

  2. Isogeometric analysis of sound propagation through laminar flow in 2-dimensional ducts

    Nørtoft, Peter; Gravesen, Jens; Willatzen, Morten

    2015-01-01

    We consider the propagation of sound through a slowly moving fluid in a 2-dimensional duct. A detailed description of a flow-acoustic model of the problem using B-spline based isogeometric analysis is given. The model couples the non-linear, steady-state, incompressible Navier-Stokes equation in ...

  3. The detectable double atmospheric ducts for RFC

    Douvenot, Rémi; Fabbro, Vincent; Hurtaud, Yvonick

    2014-01-01

    International audience Refractivity from clutter (RFC) systems are defined for retrieving the atmospheric ducts from the sea clutter echo of a radar in open sea or coastal environment. However, some ducts hardly have an effect on the clutter echo. Consequently, the RFC technique suffers inherent limitations and is unable to provide information about these ducts. To identify these ducts, one important parameter is the range at which a duct modifies the received power. This paper introduces ...

  4. Cervical thoracic duct cyst: a case report

    Park, Sang Hyun; Han, Jong Kyu; Lee, Chi Kyu; Jo, Sung Sik; Kim, Hyung Hwan; Bae, Won Kyung; Kim, Il Yung [Chunan Hospital Soonchunhyang University, Chunan (Korea, Republic of)

    2007-06-15

    Thoracic duct cysts are uncommon lesions that most commonly occur in the abdominal and thoracic portion of the thoracic duct: the cervical portion is the rarest location. The main causes of thoracic duct cyst are surgical injuries such as neck dissection and blunt trauma. We report here on a rare case of spontaneous cervical thoracic duct cyst that was noted on ultrasonography and CT. The thoracic duct cyst was confirmed by fine needle aspiration and it was treated by sclerotherapy.

  5. A method for a numeric prediction of gas turbine exhaust ducts out door noise

    Guivarch, M.

    1995-10-01

    When Electricite de France (EDF) ordered a 216 MWe gas turbine in 1986, the preliminary evaluation of the noise radiated by the exhaust duct had been a difficult problem. Therefore, EDF has developed an acoustic model of the exhaust duct of the turbine in order to compare the solutions proposed by different builders and to test the influence of the exhaust duct geometry modification on the environmental sound level. This model is based on bidimensional modelling of the exhaust duct and is developed in three main steps: a computation of the flow in the exhaust duct using a k - {epsilon} code. This computation provides the basic data needed for modeling the noise generated downstream the silencers and the convected field for the computation of sound propagation; a computation of the noise generated by the flow turbulence downstream the silencers. It is based on the Ribner modelling of noise radiated by turbulent subsonic free jets and uses the results of the flow computation. In this way, we compute the turbulent noise levels and assume that the total noise levels throughout the duct exit is the sum of the turbulent noise and of the turbine noise; a computation of sound propagation in the exhaust duct. This computation takes into account the flow and the attenuation of sound due to the silencers. In a first stage, it is validated by measurements taken when the machine is out of operating condition. The second stage provides the turbine noise levels throughout the tack exit. (author) 8 refs.

  6. Single Mode Theory for Impedance Eduction in Large-Scale Ducts with Grazing Flow

    Watson, Willie R.; Gerhold, Carl H.; Jones, Michael G.; June, Jason C.

    2014-01-01

    An impedance eduction theory for a rigid wall duct containing an acoustic liner with an unknown impedance and uniform grazing flow is presented. The unique features of the theory are: 1) non-planar waves propagate in the hard wall sections of the duct, 2) input data consist solely of complex acoustic pressures acquired on a wall adjacent to the liner, and 3) multiple higher-order modes may exist in the direction perpendicular to the liner and the opposite rigid wall. The approach is to first measure the axial propagation constant of a dominant higher-order mode in the liner sample section. This axial propagation constant is then used in conjunction with a closed-form solution to a reduced form of the convected Helmholtz equation and the wall impedance boundary condition to educe the liner impedance. The theory is validated on a conventional liner whose impedance spectrum is educed in two flow ducts with different cross sections. For the frequencies and Mach numbers of interest, no higher-order modes propagate in the hard wall sections of the smaller duct. A benchmark method is used to educe the impedance spectrum in this duct. A dominant higher-order vertical mode propagates in the larger duct for similar test conditions, and the current theory is applied to educe the impedance spectrum. Results show that when the theory is applied to data acquired in the larger duct with a dominant higher-order vertical mode, the same impedance spectra is educed as that obtained in the small duct where only the plane wave mode is present and the benchmark method is used. This result holds for each higher-order vertical mode that is considered.

  7. Analysis of Dual Rotating Rake Data from the NASA Glenn Advanced Noise Control Fan Duct with Artificial Sources

    Dahl, Milo D.; Sutliff, Daniel L.

    2014-01-01

    The Rotating Rake mode measurement system was designed to measure acoustic duct modes generated by a fan stage. Initially, the mode amplitudes and phases were quantified from a single rake measurement at one axial location. To directly measure the modes propagating in both directions within a duct, a second rake was mounted to the rotating system with an offset in both the axial and the azimuthal directions. The rotating rake data analysis technique was then extended to include the data measured by the second rake. The analysis resulted in a set of circumferential mode levels at each of the two rake microphone locations. Radial basis functions were then least-squares fit to this data to obtain the radial mode amplitudes for the modes propagating in both directions within the duct. Validation experiments have been conducted using artificial acoustic sources. Results are shown for the measurement of the standing waves in the duct from sound generated by one and two acoustic sources that are separated into the component modes propagating in both directions within the duct. Measured reflection coefficients from the open end of the duct are compared to analytical predictions.

  8. Communication Acoustics

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....

  9. The Prediction of Noise Scattered by a Wing/Ducted Fan Configuration

    Tweed, John; Dunn, Mark H.

    1999-01-01

    In this proof of concept research, a computational method was developed for predicting the sound field created by the scattering of ducted fan engine noise by a blended wing-body (BWB). It was assumed that all acoustic processes were linear and time harmonic with excitation frequency co. Inflow effects were neglected and no penetration boundary conditions were applied to the engine nacelle and BWB surfaces. A scattering approach was adopted in which the total acoustic field is written as the sum of known incident (from the engine duct) and unknown scattered parts. We further assume that the incident field is independent of the scattered field. Application of the above conditions to the equations of linearized acoustics yields the Helmholtz equation (reduced wave equation) for the scattered pressure with Neumann boundary conditions.

  10. Evaporation duct communication: Test Plan

    Anderson, K. D.

    1991-02-01

    The Evaporation Duct Communication (EDCOM) project is an effort to provide an alternative ship-to-ship communications channel using the natural environment. A microwave communication link can be used on an over-the-water, over-the-horizon path through the evaporation duct. This report shows how a microwave communication link, operating at a range separation of more than twice the line-of-sight range, can be constructed. This link can achieve about 80-percent availability at a transmission frequency of 14.5 GHz and can be constructed using off-the-shelf RF equipment. Operation of this link will provide the first set of measurements of channel capacity that can be critically dependent on the existence of an oceanic evaporation duct. Construction of this link presents a unique opportunity to study and evaluate an alternative communications channel that can be used to alleviate naval battlegroup communications load.

  11. Acoustic Neuroma

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  12. Acoustic Neuroma

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. The tumor ... press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the symptoms ...

  13. What's New in Bile Duct Cancer Research and Treatment?

    ... bile duct cancer What’s new in bile duct cancer research and treatment? Bile duct cancer is an uncommon ... Doctor After Treatment What`s New in Bile Duct Cancer Research? Other Resources and References Cancer Information Cancer Basics ...

  14. Spontaneous Bile Duct Rupture in Pregnancy

    Piotrowski, Joseph J.; Greg Van Stiegmann; R. Dale Liechty

    1990-01-01

    Spontaneous bile duct rupture occurred in a 23-year-old who required emergency Cesarean section for fetal distress. This condition has not been reported in association with pregnancy. Only forty cases of spontaneous bile duct perforation in adults have been previously reported. Seventy percent of these perforations were related to biliary calculi. Sites of perforation were evenly distributed between common hepatic duct and common bile duct. Recommended treatment includes cholecystectomy, comm...

  15. Roentgendiagnostic of the operated bile duct system

    The roentgendiagnostic after bile duct surgery shall demonstrate postoperative complications, recurrencys of the primary disease and other complications. Planning the diagnostic procedures one has to consider the preceeding operation: surgery of the gall-bladder, the common bile duct, the papilla Vateri, biliodigestive anastomosis, bile duct drainage by plastic tube, and duodenopancreatectomy. (orig.)

  16. Time-dependent difference theory for noise propagation in a two-dimensional duct

    Baumeister, K. J.

    1980-01-01

    A time-dependent numerical formulation is derived for sound propagation in a two-dimensional straight soft-walled duct in the absence of mean flow. The time-dependent governing acoustic-difference equations and boundary conditions are developed along with the maximum stable time increment. Example calculations are presented for sound attenuation in hard- and soft-wall ducts. The time-dependent analysis has been found to be superior to the conventional steady numerical analysis because of much shorter solution times and the elimination of matrix storage requirements.

  17. Minimum-Volume Conversion Duct

    The authors consider, in connection with an MHD conversion duct with known upstream and downstream stagnation conditions, what conditions will give the minimum volume, which is thought to correspond largely to the most economic conditions. On this basis, the problem of the optimum for the duct and the optima for the other components of the power plant are separated. The authors therefore discuss the most general problem of the optimum specific power σU2B2K(1 - K) for a segmented-electrode Faraday duct in the absence of thermal losses and friction, without the usual arbitrary separation of the optimization of the factor K(1 - K) and that of the product σU2; the magnetic field is assumed to be constant. The conversion equations are written in a simple form which makes it possible to utilize the calculus of variations. A system of two differential equations is obtained characterizing the evolution of the fluid. It is shown that the Mach number and the load factor are no longer independent. The integration of the differential system is performed numerically for a perfect gas in the case of thermodynamic equilibrium, the load factor at the inlet being varied for given initial conditions. It is ascertained that the evolution is different depending on whether the inlet load factor is more or less than 0.5. If a diagram is drawn showing the mean specific power-efficiency, the scatter of points representing all the optimum ducts possible, it is found that this scatter has an envelope. Similarly, all the figurate points of the ducts with constant velocities and load factors are found in an envelope inside the first. The differential equations for the optimization of a real gas are set forth in an annex, but no numerical treatment is given. (author)

  18. Optimized multisectioned acoustic liners

    Baumeister, K. J.

    1979-01-01

    A critical examination is presented of the use of optimized axially segmented acoustic liners to increase the attenuation of a liner. New calculations show that segmenting is most efficient at high frequencies with relatively long duct lengths where the attenuation is low for both uniform and segmented liners. Statistical considerations indicate little advantage in using optimized liners with more than two segments while the bandwidth of an optimized two-segment liner is shown to be nearly equal to that of a uniform liner. Multielement liner calculations show a large degradation in performance due to changes in assumed input modal structure. Finally, in order to substantiate previous and future analytical results, in-house (finite difference) and contractor (mode matching) programs are used to generate theoretical attenuations for a number of liner configurations for liners in a rectangular duct with no mean flow. Overall, the use of optimized multisectioned liners (sometimes called phased liners) fails to offer sufficient advantage over a uniform liner to warrant their use except in low frequency single mode application.

  19. Acoustic cloaking and transformation acoustics

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  20. Acoustic cloaking and transformation acoustics

    Chen Huanyang [School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006 (China); Chan, C T, E-mail: kenyon@ust.h, E-mail: phchan@ust.h [Department of Physics and the William Mong Institute of NanoScience and Technology, The Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong)

    2010-03-24

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  1. Acoustical Imaging

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  2. HAARP-Induced Ionospheric Ducts

    It is well known that strong electron heating by a powerful HF-facility can lead to the formation of electron and ion density perturbations that stretch along the magnetic field line. Those density perturbations can serve as ducts for ELF waves, both of natural and artificial origin. This paper presents observations of the plasma density perturbations caused by the HF-heating of the ionosphere by the HAARP facility. The low orbit satellite DEMETER was used as a diagnostic tool to measure the electron and ion temperature and density along the satellite orbit overflying close to the magnetic zenith of the HF-heater. Those observations will be then checked against the theoretical model of duct formation due to HF-heating of the ionosphere. The model is based on the modified SAMI2 code, and is validated by comparison with well documented experiments.

  3. Formation of artificial ionospheric ducts

    Milikh, G. M.; Papadopoulos, K.; Shroff, H; Chang, C. L.; Wallace, T; E. V. Mishin; Parrot, Michel; Berthelier, Jean-Jacques

    2008-01-01

    International audience It is well known that strong electron heating by a powerful HF-facility can lead to the formation of electron and ion density perturbations that stretch along the magnetic field line. Those density perturbations can serve as ducts for ELF waves, both of natural and artificial origin. This paper presents the first experimental evidence of plasma modifications associated with ion outflows due to HF heating. The experiments were conducted using the HAARP heater during t...

  4. Small duct primary sclerosing cholangitis without inflammatory bowel disease is genetically different from large duct disease

    Næss, Sigrid; Björnsson, Einar; Anmarkrud, Jarl A.; Al Mamari, Said; Juran, Brian D.; Lazaridis, Konstantinos N.; Chapman, Roger; Bergquist, Annika; Melum, Espen; Marsh, Steven G. E.; Schrumpf, Erik; Lie, Benedicte A.; Boberg, Kirsten Muri; Karlsen, Tom H.; Hov, Johannes R.

    2014-01-01

    Background & aims Small duct primary sclerosing cholangitis (PSC) is phenotypically a mild version of large duct PSC, but it is unknown whether these phenotypes share aetiology. We aimed to characterize their relationship by investigating genetic associations in the HLA complex, which represent the strongest genetic risk factors in large duct PSC. Methods Four classical HLA loci (HLA-A, HLA-B, HLA-C, HLA-DRB1) were genotyped in 87 small duct PSC patients, 485 large duct PSC patients and 1117 controls across three geographical regions. Results HLA-DRB1*13:01 (OR=2.0, 95% CI 1.2–3.4, P=0.01) and HLA-B*08 (OR=1.6, 95% CI 1.1–2.4, P=0.02) were significantly associated with small duct PSC compared with healthy controls. Based on the observed frequency of HLA-B*08 in small duct PSC, the strongest risk factor in large duct PSC, an estimated 32% (95% CI 4%–65%) of this population can be hypothesized to represent early stages or mild variants of large duct PSC. This subgroup may be constituted by small duct PSC patients with inflammatory bowel disease (IBD), which greatly resembled large duct PSC in its HLA association. In contrast, small duct PSC without IBD was only associated with HLA-DRB1*13:01(P=0.03) and was otherwise distinctly dissimilar from large duct PSC. Conclusions Small duct PSC with IBD resembles large duct PSC in its HLA association and may represent early stages or mild variants of large duct disease. Different HLA associations in small duct PSC without IBD could indicate that this subgroup is a different entity. HLA-DRB1*13:01 may represent a specific risk factor for inflammatory bile duct disease. PMID:24517468

  5. A state feedback electro-acoustic transducer for active control of acoustic impedance

    Samejima, Toshiya

    2003-03-01

    In this paper, a new control system in which the acoustic impedance of an electro-acoustic transducer diaphragm can be actively varied by modifying design parameters is presented and its effectiveness is theoretically investigated. The proposed control system is based on a state-space description of the control system derived from an electrical equivalent circuit of an electro-acoustic transducer to which a differentiating circuit is connected, and is designed using modern control theory. The optimal quadratic regulator is used in the control system design, with its quadratic performance index formulated for producing desired acoustic impedance. Computer simulations indicate that the acoustic impedance of the diaphragm can be significantly varied over a wide frequency range that includes the range below the resonance frequency of the electro-acoustic transducer. A computer model of the proposed control system is used to illustrate its application to semi-active noise control in a duct. It is demonstrated that the proposed control system provides substantial reductions in the noise radiating from the outlet of the duct, both in the stiffness control range and in the mass control range.

  6. Radiation acoustics

    Lyamshev, Leonid M

    2004-01-01

    Radiation acoustics is a developing field lying at the intersection of acoustics, high-energy physics, nuclear physics, and condensed matter physics. Radiation Acoustics is among the first books to address this promising field of study, and the first to collect all of the most significant results achieved since research in this area began in earnest in the 1970s.The book begins by reviewing the data on elementary particles, absorption of penetrating radiation in a substance, and the mechanisms of acoustic radiation excitation. The next seven chapters present a theoretical treatment of thermoradiation sound generation in condensed media under the action of modulated penetrating radiation and radiation pulses. The author explores particular features of the acoustic fields of moving thermoradiation sound sources, sound excitation by single high-energy particles, and the efficiency and optimal conditions of thermoradiation sound generation. Experimental results follow the theoretical discussions, and these clearl...

  7. Pancreatoduodenectomy for bile duct and ampullary cancer

    Yamaguchi, Koji

    2011-01-01

    Pylorus-preserving pancreatoduodenectomy has become a standard operation for distal and middle bile duct cancers. Bile duct cancer typically extends longitudinally and invades vertically. It frequently metastasizes to the lymph nodes and infiltrates the perineural spaces. The presence of residual cancer in the bile duct stump and lymph node metastases are significant prognostic factors. Negative surgical margins and D2 lymph node dissection are necessary for curative resection. The clinical c...

  8. Traumatic injury of the thoracic duct.

    Guzman, A E; Rossi, L; Witte, C L; Smyth, S

    2002-03-01

    Injuries to the thoracic duct are infrequent but may become life-threatening when chylous leakage persists. This report describes 6 patients with such injuries in whom the leakage resolved spontaneously in one, was corrected using microsurgical lymphatic repair or lymphatic-venous anastomosis in two, successfully treated either by ligation of the thoracic duct or insertion of a peritoneovenous shunt in two, and was eventually controlled after bilateral pleurodesis and thoracic duct ligation by insertion of a peritoneo-venous shunt in one. Conventional lymphography is superior to lymphoscintigraphy and is usually required to document disruption of the thoracic duct. PMID:11939572

  9. Methods of evaluating cleanliness of ventilation ducts

    曹勇; 罗运有; 于丹; 甘丽斯

    2009-01-01

    A testing system for evaluating cleanliness of ventilation ducts was constructed. Comparisons of four evaluation methods for quantifying the amount of dust on the inner surface of ventilation ducts are presented. The experimental results show that the wiping by solvent method is more efficient than that by the wiping method,especially used on low cleanliness duct surface. The gravimetric tape method is an efficient method of collecting dust samples on the duct surface with low amounts of dust,particularly used to check the cleanliness level after the cleaning work. The optical method can be set up rapidly and is useful for fieldwork measurements.

  10. Acoustic waveguide characteristics of the Indian Ocean - north of equator

    PrasannaKumar, S.; Murty, T.V.R.; Somayajulu, Y.K.; Murty, C.S.

    The acoustic characteristics of the waters of the Arabian Sea and Bay of Bengal, constituting the northern Indian Ocean, are analysed based on a climatological mean sound speed field. In the upper 30-40 m in the Bay of Bengal a weak surface duct...

  11. Measure Guideline: Sealing and Insulating of Ducts in Existing Homes

    Aldrich, R.; Puttagunta, S.

    2011-12-01

    This document begins with a discussion on potential cost and performance benefits of duct sealing and insulating. It continues with a review of typical duct materials and components and the overall procedures for assessing and improving the duct system.

  12. Measure Guideline. Sealing and Insulating Ducts in Existing Homes

    Aldrich, R. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Puttagunta, S. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2011-12-01

    This document begins with a discussion on potential cost and performance benefits of duct sealing and insulating. It continues with a review of typical duct materials and components and the overall procedures for assessing and improving the duct system.

  13. Acoustical Imaging

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  14. Acoustic telemetry

    National Oceanic and Atmospheric Administration, Department of Commerce — To determine movements of green turtles in the nearshore foraging areas, we deployed acoustic tags and determined their movements through active and passive...

  15. Acoustics Research

    National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....

  16. Battlefield acoustics

    Damarla, Thyagaraju

    2015-01-01

    This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

  17. Iatrogenic bile duct injuries – clinical problems

    Głuszek Stanisław

    2014-01-01

    Full Text Available Laparoscopic cholecystectomy is one of the most frequently performed surgical procedures in surgical wards. Iatrogenic bile duct injuries (IBDI incurred during the procedures are among postoperative complications that are most difficult to treat. The risk of bile duct injury is 0.2-0.4%, and their consequences are unpleasant both for the surgeon and for the patient.

  18. Attenuation of neutrons through ducts and labyrinths

    Mauro, Egidio

    2009-01-01

    Monte Carlo simulations have been performed for the attenuation of neutron radiation produced at proton accelerators through ducts and labyrinths of various design, and the results are compared with the predictions made by analytical expressions available in the literature. The results show that the so-called universal transmission curves are an appropriate and simple tool applicable in many situations, when the radiation source is not in direct view of the duct mouth. This is not the case for point sources located in front of the duct. The simulations showed that it is not possible to apply the same models because the transmission factor is strongly dependent on the cross-sectional area of the duct. A universal expression has been derived to estimate the neutron transmission through a straight duct of length d and cross-sectional area A in direct view of the source, which only depends on A and on a small set of numerical coefficients.

  19. Clinical significance of main pancreatic duct dilation on computed tomography: Single and double duct dilation

    Mark D Edge; Maarouf Hoteit; Amil P Patel; Xiaoping Wang; Deborah A Baumgarten; Qiang Cai

    2007-01-01

    AIM: To study the patients with main pancreatic duct dilation on computed tomography (CT) and thereby to provide the predictive criteria to identify patients at high risk of significant diseases, such as pancreatic cancer, and to avoid unnecessary work up for patients at low risk of such diseases.METHODS: Patients with dilation of the main pancreatic duct on CT at Emory University Hospital in 2002 were identified by computer search. Clinical course and ultimate diagnosis were obtained in all the identified patients by abstraction of their computer database records.RESULTS: Seventy-seven patients were identified in this study. Chronic pancreatitis and pancreatic cancer were the most common causes of the main pancreatic duct dilation on CT. Although the majority of patients with isolated dilation of the main pancreatic duct (single duct dilation) had chronic pancreatitis, one-third of patients with single duct dilation but without chronic pancreatitis had pancreatic malignancies, whereas most of patients with concomitant biliary duct dilation (double duct dilation) had pancreatic cancer.CONCLUSION: Patients with pancreatic double duct dilation need extensive work up and careful follow up since a majority of these patients are ultimately diagnosed with pancreatic cancer. Patients with single duct dilation, especially such patients without any evidence of chronic pancreatitis, also need careful follow-up since the possibility of pancreatic malignancy, including adenocarcinoma and intraductal papillary mucinous tumors, is still high.

  20. Bile Duct Adenoma with Oncocytic Features

    E. J. Johannesen

    2014-01-01

    Full Text Available Bile duct adenomas are benign bile duct proliferations usually encountered as an incidental finding. Oncocytic bile duct neoplasms are rare and the majority are malignant. A 61-year-old male with a diagnosis of colorectal adenocarcinoma was undergoing surgery when a small white nodule was discovered on the surface of the right lobe of his liver. This lesion was composed of cytologically bland cells arranged in tightly packed glands. These cells were immunopositive for cytokeratin 7, negative for Hep Par 1, contained mucin, and had a Ki67 proliferation index of 8%. The morphology, immunophenotype, presence of mucin, and normal appearing bile ducts, as well as the increased Ki67 proliferation rate, were consistent with a bile duct adenoma with oxyphilic (oncocytic change. Oncocytic tumors in the liver are rare; the first described in 1992. Only two bile duct adenomas with oncocytic change have been reported and neither of them had reported mucin production or the presence of normal appearing bile ducts within the lesion.

  1. Duct Remediation Program: Remediation operations and implementation

    Beckman, T.d.; Davis, M.M.; Karas, T.M.

    1992-11-01

    Plutonium holdup material has accumulated in the process ventilation duct systems at Rocky Flats. Non-Destructive Assay (NDA) measurements identified ducts containing this material. The Defense Nuclear Facility Safety Board and the Department of Energy established the criteria for remediation of these ducts. A remediation team was assembled and a program plan created. This program plan included activities such as fissile material accumulation identification, criticality safety assessments, radiation dose determinations, facility safety evaluations, prevention of future accumulation, and removal of holdup material. Several operational considerations had to be evaluated in determining completion of remediation.

  2. Duct Remediation Program: Remediation operations and implementation

    Plutonium holdup material has accumulated in the process ventilation duct systems at Rocky Flats. Non-Destructive Assay (NDA) measurements identified ducts containing this material. The Defense Nuclear Facility Safety Board and the Department of Energy established the criteria for remediation of these ducts. A remediation team was assembled and a program plan created. This program plan included activities such as fissile material accumulation identification, criticality safety assessments, radiation dose determinations, facility safety evaluations, prevention of future accumulation, and removal of holdup material. Several operational considerations had to be evaluated in determining completion of remediation

  3. Acoustic emission

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  4. A time dependent difference theory for sound propagation in ducts with flow

    Baumeister, K. J.

    1979-01-01

    A time dependent numerical solution of the linearized continuity and momentum equation is developed for sound propagation in a two-dimensional straight hard or soft wall duct with a sheared mean flow. The time dependent governing acoustic-difference equations and boundary conditions are developed along with a numerical determination of the maximum stable time increments. The analysis begins with a harmonic noise source radiating into a quiescent duct. This explicit iteration method then calculates stepwise in real time to obtain the transient as well as the 'steady' state solution of the acoustic field. Example calculations are presented for sound propagation in hard and soft wall ducts, with no flow and with plug flow. Although the problem with sheared flow has been formulated and programmed, sample calculations have not yet been examined. So far, the time dependent finite difference analysis has been found to be superior to the steady state finite difference and finite element techniques because of shorter solution times and the elimination of large matrix storage requirements.

  5. The first case of pediatric bile duct adenoma

    Zhi Li; Xiaoyi Sun; Jiexiong Feng

    2015-01-01

    Intrahepatic bile duct adenoma (BDA) is a rare benign epithelial liver tumor derived from bile duct cells. We report the first case of pediatric bile duct adenoma in the world. Furthermore, we review the diagnosis, pathology, treatment and prognosis of bile duct adenoma.

  6. Primary hepatocellular carcinoma in extrahepatic bile duct

    Jeong, Seok Tae; Ham, Soo Youn; Park, Cheol Min; Kim, Jung Hyuk; Cha, In Ho; Chung, Kyoo Byung; Suh, Woon Hyuck; Lee, Chang Hong [College of Medicine, Korea University, Seoul (Korea, Republic of)

    1991-03-15

    Obstructive jaundice due to hepatocellular carcinoma in an extrahepatic bile duct, without a mass lesion in the liver parenchyma, is extremely rare. We experienced two cases of primary hepatocellular carcinoma arising from an extrahepatic bile duct: one in a 53-year-old man whose {alpha} -fetoprotein value was 800 ng/ml, and another in a 39-year-old woman, in whom the mass lesion was found to be attached to an extrahepatic bile duct. These tumors had a well-marginated sausage-like shape on CT and US, and the contrast media passed freely along their margins on both PTC and ERCP. Recurrences of these tumors were observed in the extrahepatic bile duct 6 and 2 months after surgery, respectively.

  7. Pipe crawler development for duct elbow removal

    This paper describes the development of equipment for removing an elbow in a 36 inch diameter ventilation line by cutting from the inside. Radiation levels, high air flow and physical constraints preclude any manual rework of the ventilation system. A remotely operated pipe crawler was developed. Testing has been performed in a full-scale mockup which models the ventilation duct configuration with the exception of radiation levels. The results gathered from the testing are discussed, and illustrate the strengths and weaknesses of the crawler and plasma arc torch system. To date, the equipment has successfully completed the tasks of maneuvering through the duct geometry, performing the two required cuts, and backing out of the duct mockup. The elbow successfully fell away from the main duct, showing that the line would be clear of obstructions

  8. [Isolated neurofibroma of the common bile duct].

    Carbia, S; Pagola, J; Flaster, N; Guida, A; Jufe, L; González, B; Caniparoli, A

    1995-01-01

    The neurogenic tumors in the biliary tract are rare and usually are amputation neuroma that occur after cholecystectomy. We describe a case of isolated neurofibroma of the common bile duct in a young man not cholecystectomized. The patient suffered recurrent episodes of abdominal pain, vomiting and weight loss without clinical signs of Von Recklinghausen's disease or jaundice. The hepatogram was normal. The echography indicated a solid formation with obstruction of the proximal common bile duct. In the ERCP the stenosis was found. Surgical excision of the tumor and anastomosis of bilateral hepatic ducts and jejunum were carried out. At microscopic examination intraparietal neurofibroma of the common bile duct was found. As isolated entity, we know of only one reported case. PMID:8731581

  9. Transmission of wave energy in curved ducts

    Rostafinski, W.

    1973-01-01

    A formation of wave energy flow was developed for motion in curved ducts. A parametric study over a range of frequencies determined the ability of circular bends to transmit energy for the case of perfectly rigid walls.

  10. Investigation of heat transfer in porous duct

    Athani, Abdulgaphur; Khan, T. M. Yunus

    2016-05-01

    Investigation of heat transfer in a square porous duct is carried out. The porous medium is sandwiched between inner and outer surface of a square duct. The flow is assumed to follow the Darcy law. The governing momentum and energy equations are non-dimensionalised and then converted to algebraic form of equations using finite element method. Galerkin method is used to transform the partial differential equations into simpler algebraic equations then solved in a iterative manner to arrive at the solution. The results are presented with respect to various geometric and physical parameters such as depth of porous medium, Rayleigh number etc. It is found that the isotherms and the streamlines take symmetrical position along the vertical central line of square duct. The isotherms are penetrated into deeper area at upper half of duct as compared to lower half.

  11. Reference values of MRI measurements of the common bile duct and pancreatic duct in children

    Magnetic resonance imaging/cholangiopancreatography (MRI/MRCP) is now an essential imaging modality for the evaluation of biliary and pancreatic pathology in children, but there are no data depicting the normal diameters of the common bile duct (CBD) and pancreatic duct. Recognition of abnormal duct size is important and the increasing use of MRCP necessitates normal MRI measurements. To present normal MRI measurements for the common bile duct and pancreatic duct in children. In this retrospective study we searched all children ages birth to 10 years in our MR urography (MRU) database from 2006 until 2013. We excluded children with a history of hepatobiliary or pancreatic surgery. We stratified 204 children into five age groups and retrospectively measured the CBD and the pancreatic duct on 2-D axial and 3-D coronal T2-weighted sequences. We performed statistical analysis, using logistic and linear regressions to detect the age association of the visibility and size of the duct measurements. We used non-parametric tests to detect gender and imaging plane differences. Our study included 204 children, 106 (52%) boys and 98 (48%) girls, with a median age of 33 months (range 0-119 months). The children were distributed into five age groups. The common bile duct was visible in all children in all age groups. The pancreatic duct was significantly less visible in the youngest children, group 1 (54/67, 80.5%; P = 0.003) than in the oldest children, group 5 (22/22, 100%). In group 2 the pancreatic duct was seen in 19/21 (90.4%), in group 3 52/55 (94.5%), and in group 4 39/39 (100%). All duct measurements increased with age (P < 0.001; r-value > 0.423), and the incremental differences between ages were significant. The measurement variations between the axial and coronal planes were statistically significant (P < 0.001); however these differences were fractions of millimeters. For example, in group 1 the mean coronal measurement of the CBD was 2.1 mm and the axial

  12. Reference values of MRI measurements of the common bile duct and pancreatic duct in children

    Gwal, Kriti; Bedoya, Maria A.; Patel, Neal; Darge, Kassa; Anupindi, Sudha A. [University of Pennsylvania Perelman School of Medicine, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Rambhatla, Siri J. [Beth Israel Medical Center, Department of Pediatrics, Newark, NJ (United States); Sreedharan, Ram R. [University of Pennsylvania, Departments of Gastroenterology, Hepatology and Nutrition, The Children' s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA (United States)

    2015-08-15

    Magnetic resonance imaging/cholangiopancreatography (MRI/MRCP) is now an essential imaging modality for the evaluation of biliary and pancreatic pathology in children, but there are no data depicting the normal diameters of the common bile duct (CBD) and pancreatic duct. Recognition of abnormal duct size is important and the increasing use of MRCP necessitates normal MRI measurements. To present normal MRI measurements for the common bile duct and pancreatic duct in children. In this retrospective study we searched all children ages birth to 10 years in our MR urography (MRU) database from 2006 until 2013. We excluded children with a history of hepatobiliary or pancreatic surgery. We stratified 204 children into five age groups and retrospectively measured the CBD and the pancreatic duct on 2-D axial and 3-D coronal T2-weighted sequences. We performed statistical analysis, using logistic and linear regressions to detect the age association of the visibility and size of the duct measurements. We used non-parametric tests to detect gender and imaging plane differences. Our study included 204 children, 106 (52%) boys and 98 (48%) girls, with a median age of 33 months (range 0-119 months). The children were distributed into five age groups. The common bile duct was visible in all children in all age groups. The pancreatic duct was significantly less visible in the youngest children, group 1 (54/67, 80.5%; P = 0.003) than in the oldest children, group 5 (22/22, 100%). In group 2 the pancreatic duct was seen in 19/21 (90.4%), in group 3 52/55 (94.5%), and in group 4 39/39 (100%). All duct measurements increased with age (P < 0.001; r-value > 0.423), and the incremental differences between ages were significant. The measurement variations between the axial and coronal planes were statistically significant (P < 0.001); however these differences were fractions of millimeters. For example, in group 1 the mean coronal measurement of the CBD was 2.1 mm and the axial

  13. Evaporation duct communication: Test plan, part 2

    Anderson, K. D.; Rogers, L. T.

    1991-11-01

    This document is a continuation and expansion of an earlier study that examines the feasibility of using the evaporation duct to support an alternative high-speed communication system for Navy applications. This Evaporation Duct Communication (EDCOM) experiment is a unique opportunity to evaluate another communication channel that can alleviate Navy ship-to-ship communication problems. Therefore, it is strongly recommended to proceed with this measurement program.

  14. Ultrasonographic findings of intrahepatic bile duct stone

    Kim, Yoon Suk; Na, Hae Kyung; Yoon, Chong Hyun [National Medical Center, Seoul (Korea, Republic of)

    1989-10-15

    The intrahepatic duct stones are prevalent in East Asia and pose serious health problem because of the frequent recurrence and often associated suppurative cholangitis. Accurate diagnosis and localization of intrahepatic duct stones are essential to good prognosis and selection of adequate therapeutic method. We studied 112 cases of intrahepatic duct stones diagnosed with ultrasound and confirmed by operation or other radiologic studies for recent 3 years from May 1986 to May 1989 at Department Of Radiology, National Medical Center, and analysed ultrasonographic findings. The results were as follows: 1. Among 112 cases, 73 (65%) were female, 39 (35%) were male with predominancy in 5th decade. 2. The most common location of intrahepatic duct stones was left intrahepatic duct in 48 cases (43%), followed by right intrahepatic duct in 42 cases (37.5%) and both intrahepatic ducts in 22 cases (19.5%). In respect of segmental distribution, left lateral segment is the most common location (53 cases, 34%), followed by right posterior segment (43 cases, 27%). 3. Ultrasonographic findings were as follows: Nodular pattern is the most common (59 cases, 53%), followed by tubular or linear impacted pattern (23 cases, 20%), irregular heterogenous conglomerated mass (13 cases, 12%), smooth homogenous single mass (10 cases, 9%) and mixed (7 cases, 6%) in orders. Ductal dilatations were classified by diffuse dilatation (16 cases, 14%), localized dilatation (50 case, 45%) and no dilatation (46 cases, 41%). Many of the tubular impacted stones showed no ductal dilatation and single mass showed ductal dilatations in all cases. 4. In 53 cases (47%), combined extrahepatic duct stones were present. 5. As associated findings, liver cirrhosis in 11 cases (10%), cholangitis in 9 cases (8%), cholecystitis in 7 cases (6%), hepatic and pericholangitic abscess in 3 cases(3%) and CBD cancer, GB cancer, acute pancreatitis in 2 cases (2%) respectively.

  15. Palliative irradiation of the bile ducts

    Kutzner, J.; Klose, K.; Keller, E.

    1985-11-01

    Carcinoma of the common hepatic bile duct or common bile duct were treated by interstitial irradiation with gold seeds using the percutaneous transhepatic drainage partly boosted by external irradiation. The interstitial dose of 50 Gy was given in two applications and 40 Gy by linac. Twice histological examination showed wide tumor destruction of local irradiation, but also much more tumor extension than seen before by diagnostic investigation. Mostly the therapy is only palliative because of the infiltration of liver and lymphnodes. (orig.).

  16. Radiotherapy of bile duct carcinoma

    Twenty-six patients with cholangiocarcinoma and nineteen patients with carcinoma of the gallbladder treated with external radiotherapy were analyzed. Of the twenty-six patients, eighteen had cancer of the hepatic hilus (Klatskin), four intrahepatic and the remaining four extrahepatic cholangiocarcinoma. All but two of the patients had advanced disease. Thirty-three patients received primary irradiation for unresectable tumors, ten patients adjuvant irradiation after non-curative gross tumor resection, and two patients preoperative radiotherapy. Patients with cholangiocarcinoma who underwent radiotherapy with relatively small radiation field tolerated the treatment well, but there was no significant difference in survival according to field size or radiation doses (TDF). On the other hand, patients with carcinoma of gallbladder were treated with larger field size and lower dose. In the patients without gross tumor resection, those receiving radiation doses≥90 TDF had significantly longer survival than 2) had longer survival (p=0.07). The patients with gross tumor resection had significantly longer survival than that without resection in both cholangiocarcinoma and carcinoma of gallbladder. Postmortem examination revealed tumor recurrence even in the patients with gross tumor resection, but widespread distant metastases were present simultaneously. Cholangitis and liver abscess were special and lethal conditions related to these carcinomas, and intensive therapy must be developed for these conditions. External radiotherapy may be effective in the treatment of bile duct carcinoma in terms of palliation and survival. (author)

  17. A Comparison of Simulation Capabilities for Ducts

    Miller, William A [ORNL; Smith, Matt K [ORNL; Gu, Lixing [Florida Solar Energy Center (FSEC); New, Joshua Ryan [ORNL

    2014-11-01

    Typically, the cheapest way to install a central air conditioning system in residential buildings is to place the ductwork in the attic. Energy losses due to duct-attic interactions can be great, but current whole-house models are unable to capture the dynamic multi-mode physics of the interactions. The building industry is notoriously fragmented and unable to devote adequate research resources to solve this problem. Builders are going to continue to put ducts in the attic because floor space is too expensive to closet them within living space, and there are both construction and aesthetic issues with other approaches such as dropped ceilings. Thus, there is a substantial need to publicly document duct losses and the cost of energy used by ducts in attics so that practitioners, builders, homeowners and state and federal code officials can make informed decisions leading to changes in new construction and additional retrofit actions. Thus, the goal of this study is to conduct a comparison of AtticSim and EnergyPlus simulation algorithms to identify specific features for potential inclusion in EnergyPlus that would allow higher-fidelity modeling of HVAC operation and duct transport of conditioned air. It is anticipated that the resulting analysis from these simulation tools will inform energy decisions relating to the role of ducts in future building energy codes and standards.

  18. Double common bile duct: A case report

    Srdjan P Djuranovic; Milenko B Ugljesic; Nenad S Mijalkovic; Viktorija A Korneti; Nada V Kovacevic; Tamara M Alempijevic; Slaven V Radulovic; Dragan V Tomic; Milan M Spuran

    2007-01-01

    Double common bile duct (DCBD) is a rare congenital anomaly in which two common bile ducts exist. One usually has normal drainage into the papilla duodeni major and the other usually named accessory common bile duct (ACBD) opens in different parts of upper gastrointestinal tract (stomach, duodenum, ductus pancreaticus or septum). This anomaly is of great importance since it is often associated with biliary lithiasis, choledochal cyst, anomalous pancreaticobiliary junction (APBJ) and upper gastrointestinal tract malignancies. We recently recognized a rare case of DCBD associated with APBJ with lithiasis in better developed common bile duct. The opening site of ACBD was in the pancreatic duct. The anomaly was suspected by transabdominal ultrasonography and finally confirmed by endoscopic retrograde cholangiopancreatography (ERCP) followed by endoscopic sphincterotomy and stone extraction. According to the literature, the existence of DCBD with the opening of ACBD in the pancreatic duct is most frequently associated with APBJ and gallbladder carcinoma. In case of DCBD, the opening site of ACBD is of greatest clinical importance because of its close implications with concomitant pathology. The adequate diagnosis of this rare anomaly is significant since the operative complications may occur in cases with DCBD which is not recognized prior to surgical treatment.

  19. Computed tomography and the dilated pancreatic duct: An ominous sign

    Palmer Gold, R.; Seaman, W.B.

    1981-01-15

    The main pancreatic duct has been visualized with both ultrasound and computed tomography. A normal pancreatic duct has been reported using CT, and controversy persists over whether a normal duct can be routinely imaged with ultrasound. The dilated pancreatic duct has always been associated with disease - usually pancreatitis or a proximal obstructing pancreatic carcinoma. In the patient with no clinical history or laboratory data suggesting pancreatitis, a dilated pancreatic duct implies a proximal tumor.

  20. Modeling the effects of wind tunnel wall absorption on the acoustic radiation characteristics of propellers

    Baumeister, K. J.; Eversman, W.

    1986-01-01

    Finite element theory is used to calculate the acoustic field of a propeller in a soft walled circular wind tunnel and to compare the radiation patterns to the same propeller in free space. Parametric solutions are present for a 'Gutin' propeller for a variety of flow Mach numbers, admittance values at the wall, microphone position locations, and propeller to duct radius ratios. Wind tunnel boundary layer is not included in this analysis. For wall admittance nearly equal to the characteristic value of free space, the free field and ducted propeller models agree in pressure level and directionality. In addition, the need for experimentally mapping the acoustic field is discussed.

  1. Effect of duct shape, Mach number, and lining construction on measured suppressor attenuation and comparison with theory

    Olsen, W. A.; Krejsa, E. A.; Coats, J. W.

    1972-01-01

    Noise attenuation was measured for several types of cylindrical suppressors that use a duct lining composed of honeycomb cells covered with a perforated plate. The experimental technique used gave attenuation data that were repeatable and free of noise floors and other sources of error. The suppressor length, the effective acoustic diameter, suppressor shape and flow velocity were varied. The agreement among the attenuation data and two widely used analytical models was generally satisfactory. Changes were also made in the construction of the acoustic lining to measure their effect on attenuation. One of these produced a very broadband muffler.

  2. A radiographic study of nasopalatine duct cysts

    The purpose of this study was to evaluate the clinical and radiographic features of 35 cases of nasopalatine duct cyst by means of the analysis of periapical and/or occlusal radiograms in 35 persons visited the Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University and Chonbuk National University. The obtained results were as follows: 1. The incidence of nasopalatine duct cysts was higher in males (74.3%) than in females (25.7%). 2. The nasopalatine duct cysts were the most frequently occurred in the 4th decades (34.3%). The 6th and 7th decades (17.1%, 17.1%) were next in order to frequency followed by the 5th decades (14.3%), the 3rd decades (8.6%), the 2nd decades (5.7%), and 8th decades (2.9%). 3. In the signs and symptoms of nasopalatine duct cysts, 25.7% were swelling, 17.1% were swelling and tenderness, 20.0% were swelling and pain, and 37.2% were a symptom. 4. In the shape of nasopalatine duct cysts, 40.0% were round type, 48.6% 11.8% were heart type. 5. In symmetry of the nasopalatine duct cysts, 11.4% were 6-10 mm, 48.6% were 11-20 mm, 25.7% were 21-30 mm, and 14.3% were 31-40 mm. 6. In the periphery of nasopalatine duct cysts, 82.9% were distinct, 17.1% were relatively distinct. 7. In the change of root, 51.5% were intact, 17.1% were root divergence, 20.0% were root resorption, and 11.4% were root divergence and resorption.

  3. Ultrasound appearance of chronic mammary duct ectasia

    Mammary duct ectasia (MDE), also called periductal mastitis, mammary dysplasia, or plasma cell mastitis, is a benign condition of the mammary gland first described by Haagensen in 1951. The etiology of MDE is unknown and its pathogenesis still controversial; the periductal inflammation could be either the cause or the result of dilated damaged ducts. The process is usually bilateral and asymptomatic, with only a small percentage of patients presenting with symptoms that may include long course of tumour formation, usually subareolar breast lumps, nipple discharge, nipple retraction, mastalgia, and mammary abscess or fistulas. Mammographic presentation of MDE is well known; its features include periductal calcification, benign intraductal calcification, and retroareolar duct dilatation. The periductal calcification results from dystrophic calcification and forms calcified rings or very dense, oval, elongated calcifications, each with a central lucency representing the dilated duct. Intraductal calcifications of duct ectasia represent inspissated intraductal material and are typically of uniform high density, often needle-like, and occasionally branching. Occasionally, there are no mammographic findings, and the diagnosis must rely on sonographic features. Appearance of MDE on ultrasonography (US) depends on the stage of the disease and the contents of the dilated ducts. The acute presentation has been demonstrated in the literature more often than has its chronic counterpart. In the former, duct content can vary from anechoic to isoechoic with surrounding fatty tissue. In chronic MDE, episodes of inflammation are longer. This tends to result in secretions that have a more solid, cheesy texture, partly due to cholesterol crystals, foam cells, and inflammatory cells. For both types of MDE, the appearance can mimic high-grade ductal carcinoma in situ (DCIS) on US. In this essay, 2 chronic MDE cases are presented and their US appearance discussed. Our goal is to explore

  4. Ultrasound appearance of chronic mammary duct ectasia

    Duchesne, N. [Ottawa Hospital, Dept. of Radiology, Ottawa, Ontario (Canada)]. E-mail: nathalie_duchesne_22@yahoo.ca; Skolnik, S. [Univ. of Toronto, Dept. of Family Medicine, Toronto, Ontario (Canada); Bilmer, S. [Ottawa Hospital, Dept. of Radiology, Ottawa, Ontario (Canada)

    2005-12-15

    Mammary duct ectasia (MDE), also called periductal mastitis, mammary dysplasia, or plasma cell mastitis, is a benign condition of the mammary gland first described by Haagensen in 1951. The etiology of MDE is unknown and its pathogenesis still controversial; the periductal inflammation could be either the cause or the result of dilated damaged ducts. The process is usually bilateral and asymptomatic, with only a small percentage of patients presenting with symptoms that may include long course of tumour formation, usually subareolar breast lumps, nipple discharge, nipple retraction, mastalgia, and mammary abscess or fistulas. Mammographic presentation of MDE is well known; its features include periductal calcification, benign intraductal calcification, and retroareolar duct dilatation. The periductal calcification results from dystrophic calcification and forms calcified rings or very dense, oval, elongated calcifications, each with a central lucency representing the dilated duct. Intraductal calcifications of duct ectasia represent inspissated intraductal material and are typically of uniform high density, often needle-like, and occasionally branching. Occasionally, there are no mammographic findings, and the diagnosis must rely on sonographic features. Appearance of MDE on ultrasonography (US) depends on the stage of the disease and the contents of the dilated ducts. The acute presentation has been demonstrated in the literature more often than has its chronic counterpart. In the former, duct content can vary from anechoic to isoechoic with surrounding fatty tissue. In chronic MDE, episodes of inflammation are longer. This tends to result in secretions that have a more solid, cheesy texture, partly due to cholesterol crystals, foam cells, and inflammatory cells. For both types of MDE, the appearance can mimic high-grade ductal carcinoma in situ (DCIS) on US. In this essay, 2 chronic MDE cases are presented and their US appearance discussed. Our goal is to explore

  5. A radiographic study of nasopalatine duct cysts

    Jun, Chan Duck; Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral Radiology, College of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    1993-02-15

    The purpose of this study was to evaluate the clinical and radiographic features of 35 cases of nasopalatine duct cyst by means of the analysis of periapical and/or occlusal radiograms in 35 persons visited the Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University and Chonbuk National University. The obtained results were as follows: 1. The incidence of nasopalatine duct cysts was higher in males (74.3%) than in females (25.7%). 2. The nasopalatine duct cysts were the most frequently occurred in the 4th decades (34.3%). The 6th and 7th decades (17.1%, 17.1%) were next in order to frequency followed by the 5th decades (14.3%), the 3rd decades (8.6%), the 2nd decades (5.7%), and 8th decades (2.9%). 3. In the signs and symptoms of nasopalatine duct cysts, 25.7% were swelling, 17.1% were swelling and tenderness, 20.0% were swelling and pain, and 37.2% were a symptom. 4. In the shape of nasopalatine duct cysts, 40.0% were round type, 48.6% 11.8% were heart type. 5. In symmetry of the nasopalatine duct cysts, 11.4% were 6-10 mm, 48.6% were 11-20 mm, 25.7% were 21-30 mm, and 14.3% were 31-40 mm. 6. In the periphery of nasopalatine duct cysts, 82.9% were distinct, 17.1% were relatively distinct. 7. In the change of root, 51.5% were intact, 17.1% were root divergence, 20.0% were root resorption, and 11.4% were root divergence and resorption.

  6. Acoustic lenses

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  7. Evaluating the Acoustic Effect of Over-the-Rotor Foam-Metal Liner Installed on a Low Speed Fan Using Virtual Rotating Microphone Imaging

    Sutliff, Daniel L.; Dougherty, Robert P.; Walker, Bruce E.

    2010-01-01

    An in-duct beamforming technique for imaging rotating broadband fan sources has been used to evaluate the acoustic characteristics of a Foam-Metal Liner installed over-the-rotor of a low-speed fan. The NASA Glenn Research Center s Advanced Noise Control Fan was used as a test bed. A duct wall-mounted phased array consisting of several rings of microphones was employed. The data are mathematically resampled in the fan rotating reference frame and subsequently used in a conventional beamforming technique. The steering vectors for the beamforming technique are derived from annular duct modes, so that effects of reflections from the duct walls are reduced.

  8. The "flying" bile duct: avulsion of the common bile duct in a plane crash survivor.

    Mohan, H

    2012-02-01

    Blunt trauma is an unusual cause of extrahepatic bile duct injury. This is a case of a 51-year-old gentleman who sustained a significant seatbelt injury in a plane crash. Laparotomy, performed due to persistent abdominal pain, revealed that the common bile duct (CBD) was completely avulsed from the duodenum. Following insertion of drains and transfer to a hepatobiliary centre, the devascularised CBD was excised and replaced with a roux-en-y hepaticojejunostomy. Necrotic tissue was debrided from the pancreatic head. A persistent bile leak developed from the sub-hepatic drain. Repeat laparotomy revealed a bile leak from small ducts on the liver surface. Ligation of the ducts and bioglue sealing of the area were successfully performed. Subsequent to this a pancreatic fistula developed from the main pancreatic duct, which has since resolved. This unusual case illustrates the need for prompt recognition and early repair to optimise outcomes in traumatic CBD injury.

  9. ITER L 6 equatorial maintenance duct remote handling study

    The status and conclusions of a preliminary study of equatorial maintenance duct remote handling is reported. Due to issues with the original duct design a significant portion of the study had to be refocused on equatorial duct layout studies. The study gives an overview of some of the options for design of these ducts and the impact of the design on the equipment to work in the duct. To develop a remote handling concept for creating access through the ducts the following design tasks should be performed: define the operations sequences for equatorial maintenance duct opening and closing; review the remote handling requirements for equatorial maintenance duct opening and closing; design concept for door and pipe handling equipment and to propose preliminary procedures for material handling outsides the duct. 35 figs

  10. In-duct identification of a rotating sound source with high spatial resolution

    Heo, Yong-Ho; Ih, Jeong-Guon; Bodén, Hans

    2015-11-01

    To understand and reduce the flow noise generation from in-duct fluid machines, it is necessary to identify the acoustic source characteristics precisely. In this work, a source identification technique, which can identify the strengths and positions of the major sound radiators in the source plane, is studied for an in-duct rotating source. A linear acoustic theory including the effects of evanescent modes and source rotation is formulated based on the modal summation method, which is the underlying theory for the inverse source reconstruction. A validation experiment is conducted on a duct system excited by a loudspeaker in static and rotating conditions, with two different speeds, in the absence of flow. Due to the source rotation, the measured pressure spectra reveal the Doppler effect, and the amount of frequency shift corresponds to the multiplication of the circumferential mode order and the rotation speed. Amplitudes of participating modes are estimated at the shifted frequencies in the stationary reference frame, and the modal amplitude set including the effect of source rotation is collected to investigate the source behavior in the rotating reference frame. By using the estimated modal amplitudes, the near-field pressure is re-calculated and compared with the measured pressure. The obtained maximum relative error is about -25 and -10 dB for rotation speeds at 300 and 600 rev/min, respectively. The spatial distribution of acoustic source parameters is restored from the estimated modal amplitude set. The result clearly shows that the position and magnitude of the main sound source can be identified with high spatial resolution in the rotating reference frame.

  11. Size limitations in semicircular duct systems

    Muller

    1999-06-01

    The present article discusses mechanical requirements and limitations which are applicable to the construction of the system of semicircular ducts, especially to its size. The simplified case of a single, uniform duct system has been considered which can be described by a second order equation of motion. The principal functional quantities for this rotation-sensor are: (1) response speed; (2) sensitivity; and (3) regular flow. The response speed of a single, uniform semicircular duct is characterized by the short time constant (T2) which is dependent on the duct radius (r). Its estimated range is from 0.04 ms in the smallest to 140 ms in the largest known labyrinth. The sensitivity is characterized by the maximal endolymph displacement after a step stimulus (xmax). Its estimated range is from 0.0016 &mgr;m to 5.97 mm (6.56 decades!), assuming an input angular velocity of omega=1 rad s-1. The Reynolds number is a measure for an undisturbed laminar flow. Its estimated range varies from 7.38.10(-4)to 45.1 for omega=1 rad s-1. The above data follow from graphs in which, for a single uniform duct, circuit radius (R) is plotted against duct radius (r) for labyrinths of 233 species belonging to different vertebrate-groups. A relation R =38.9. r1.60was determined. The smallest labyrinth was found in a carp larva (Cyprinus), the largest in a whale shark (Rhincodon). Large whales possess labyrinths of average mammalian size. It is revealed that semicircular duct size is bound by requirements concerning regular flow and by a too low response speed for large labyrinths, and by a too low sensitivity for small labyrinths. Other important quantities are mechanical amplification factors which are a consequence of more complex vestibular constructions than a single uniform duct circuit. Allometric relationships are interpreted as compromises between the quantities mentioned. A hypothesis for the relatively large semicircular duct sizes of fishes, especially Elasmobranchii, compared

  12. Numerical simulation of flow past circular duct

    Ze-gao YIN; Xian-wei Cao; Hong-da SHI; Jian MA

    2010-01-01

    The Renormalization Group(RNG)k-ε turbulence model and Volume of Fluid(VOF)method were employed to simulate the flow past a circular duct in order to obtain and analyze hydraulic parameters.According to various upper and bottom gap ratios,the force on the duct was calculated.When the bottom gap ratio is 0,the drag force coefficient,lift force coefficient,and composite force reach their maximum values,and the azimuth reaches its minimum.With an increase of the bottom gap ratio from 0 to 1,the drag force coefficient and composite force decrease sharply,and the lift force coefficient does not decreases so much,but the azimuth increases dramatically.With a continuous increase of the bottom gap ratio from 1 upward,the drag force coefficient,lift force coefficient,composite force,and azimuth vary little.Thus,the bottom gap ratio is the key factor influencing the force on the circular duct.When the bottom gap ratio is less than 1,the upper gap ratio has a remarkable influence on the force of the circular duct.When the bottom gap ratio is greater than 1,the variation of the upper gap ratio has little influence on the force of the circular duct.

  13. Numerical simulation of flow past circular duct

    Ze-gao YIN

    2010-06-01

    Full Text Available On the basis of Fluent software, Renormalization Group (RNGk-ε turbulent model and Volume of Fluid (VOF method are employed to simulate the flow past circular duct to obtain and analyze the hydraulic parameters. According to various upper and bottom gap-ratios, the force on duct is calculated. Firstly, when bottom gap-ratio is 0, drag force coefficient, lift force coefficient and composite force reach the maximum respectively and azimuth reaches the minimum. Secondly, with the increase of bottom gap-ratio from 0 to 1, drag force coefficient and composite force decrease sharply, lift force coefficient decreases a little, but azimuth increases dramatically. Thirdly, with the continuous increase of bottom gap-ratio from 1, drag force coefficient, lift force coefficient, composite force and azimuth vary little. So, bottom gap-ratio is the key factor influencing the force on circular duct. When bottom gap-ratio is less than 1, upper gap-ratio has the remarkable influence on the circular duct force. When bottom gap-ratio is greater than 1, the varation of upper gap-ratio has a little influence on the circular duct force.

  14. Salivary duct carcinoma of the parotid gland

    Mona Mlika

    2012-01-01

    Full Text Available Salivary duct carcinoma of the parotid gland is an uncommon tumor, highly aggressive. About 200 cases have been reported in the English literature. Pathomorphologically, these tumors showed great similarities to ductal carcinoma of the female breast, which is why they described this tumor as "salivary duct carcinoma." The authors describe a new case of salivary duct carcinoma of the parotid gland. We present the case of a 50-year-old patient with progressive facial paralysis. The MRI examination of the head showed two ill-defined formations. A malignant tumor was strongly suspected, so that a total left parotidectomy with excision of the adjacent facial nerve and left lymph node dissection was performed. Microscopic examination concluded to a salivary duct carcinoma of the left parotid gland negative with Her2/neu antibody with lymph node metastasis. There were no recurrences or metastases within 3 years of follow-up. Salivary duct carcinoma of the parotid gland is a rare tumor with an aggressive behavior. This is due to its propensity to infiltrate distant organs. The diagnosis is based on microscopic examination. Treatment modalities are non-consensual, but some authors advocate the necessity of aggressive approach, especially in tumors negative with Heur2/neu antibody. This is due to the fact that the overexpression of this antigen was reported to be associated with a poor prognosis.

  15. THE ACOUSTICS OF AUTOMOTIVE MUFFLERS: 1D-3D BEM ANALYSES, EXPERIMENTAL VALIDATION AND OPTIMIZATION

    Auriemma, Fabio

    2011-01-01

    A number of numerical and experimental studies, performed in the field of technical flow duct acoustics, are presented in this thesis. The analyses have been implemented on the automotive mufflers, and the fluid-dynamic aspects have been taken into account too. The noise attenuation characteristics of a three pass perforated muffler with final end resonator have been investigated. Acoustic performances have been quantified by the Transmission Loss (TL) parameter, and different numerical...

  16. FLUID FLOW IN ROTATING HELICAL SQUARE DUCTS

    Chen Hua-jun; Zhang Ben-zhao; Zhang Jin-suo

    2003-01-01

    A numerical study is made for a fully developed laminar flow in rotating helical pipes.Due to the rotation, the Coriolis force can also contribute to the secondary flow.The interaction between rotation, torsion, and curvature complicates the flow characteristics.The effects of rotation and torsion on the flow transitions are studied in details.The results show that there are obvious differences between the flow in rotating ducts and in helical ducts without rotation.Certain hitherto unknown flow patterns are found.The effects of rotation and torsion on the friction factor are also examined.Present results show the characteristics of the fluid flow in rotating helical square ducts.

  17. Percutaneous treatment of benign bile duct strictures

    Koecher, Martin [Department of Radiology, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)]. E-mail: martin.kocher@seznam.cz; Cerna, Marie [Department of Radiology, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Havlik, Roman [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Kral, Vladimir [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Gryga, Adolf [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Duda, Miloslav [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)

    2007-05-15

    Purpose: To evaluate long-term results of treatment of benign bile duct strictures. Materials and methods: From February 1994 to November 2005, 21 patients (9 men, 12 women) with median age of 50.6 years (range 27-77 years) were indicated to percutaneous treatment of benign bile duct stricture. Stricture of hepatic ducts junction resulting from thermic injury during laparoscopic cholecystectomy was indication for treatment in one patient, stricture of hepaticojejunostomy was indication for treatment in all other patients. Clinical symptoms (obstructive jaundice, anicteric cholestasis, cholangitis or biliary cirrhosis) have appeared from 3 months to 12 years after surgery. Results: Initial internal/external biliary drainage was successful in 20 patients out of 21. These 20 patients after successful initial drainage were treated by balloon dilatation and long-term internal/external drainage. Sixteen patients were symptoms free during the follow-up. The relapse of clinical symptoms has appeared in four patients 9, 12, 14 and 24 months after treatment. One year primary clinical success rate of treatment for benign bile duct stricture was 94%. Additional two patients are symptoms free after redilatation (15 and 45 months). One patient is still in treatment, one patient died during secondary treatment period without interrelation with biliary intervention. The secondary clinical success rate is 100%. Conclusion: Benign bile duct strictures of hepatic ducts junction or biliary-enteric anastomosis are difficult to treat surgically and endoscopically inaccessible. Percutaneous treatment by balloon dilatation and long-term internal/external drainage is feasible in the majority of these patients. It is minimally invasive, safe and effective.

  18. Bundle duct interaction studies for fuel assemblies

    It is known that the wire-wrapped rods and duct in an LMFBR are undergoing a gradual structural distortion from the initially uniform geometry under the combined effects of thermal expansion and irradiation induced swelling and creep. These deformations have a significant effect on flow characteristics, thus causing changes in thermal behavior such as cladding temperature and temperature distribution within a bundle. The temperature distribution may further enhance or retard irradiation induced deformation of the bundle. This report summarizes the results of the continuing effort in investigating the bundle-duct interaction, focusing on the need for the large development plant

  19. Countercurrent flow limitation in narrow rectangular ducts

    Countercurrent air-water two phase flow limitation in vertical narrow rectangular ducts was investigated. The scale effect was investigated using three narrow rectangular ducts with different gaps (2 x 100, 5 x 100, 10 x 100 mm). The experimental data showed similar tendency in spite of gap or upper plenum liquid level. The Wallis type correlation with constant C = 0.65 gave a good agreement with the experimental data. A comparison with the prediction by the envelope theory using the Bharathan friction factor correlation was also discussed. (author)

  20. Giant muellerian duct cyst: a case report

    Han, Yoo Mie; Lee, Sun Wha; Park, Young Yo [College of Medicine, Ewha Womans University, Seoul (Korea, Republic of)

    1995-07-15

    We report a case of giant Muellerian duct cyst in a 6 month-old-boy with urinary tract infection. A mass displacing the bladder and prostatic urethra anteriorly was found on the voiding cystourethrogram, and it was a oval shaped retrovesical anechoic cyst on the abdominal ultrasonogram. On MRI, it was a tear-drop shaped cyst of isosignal intensity with a projection toward the prostatic urethra and located in the midline of vesicorectal space. Grossly, the cyst had communication with prostatic urethra and both vas deferenses were drained to the cyst. Pathologically it was confirmed as a Muellerrian duct cyst lined with squamous spithelium.

  1. Physics of Acoustic Radiation from Jet Engine Inlets

    Tam, Christopher K. W.; Parrish, Sarah A.; Envia, Edmane; Chien, Eugene W.

    2012-01-01

    Numerical simulations of acoustic radiation from a jet engine inlet are performed using advanced computational aeroacoustics (CAA) algorithms and high-quality numerical boundary treatments. As a model of modern commercial jet engine inlets, the inlet geometry of the NASA Source Diagnostic Test (SDT) is used. Fan noise consists of tones and broadband sound. This investigation considers the radiation of tones associated with upstream propagating duct modes. The primary objective is to identify the dominant physical processes that determine the directivity of the radiated sound. Two such processes have been identified. They are acoustic diffraction and refraction. Diffraction is the natural tendency for an acoustic wave to follow a curved solid surface as it propagates. Refraction is the turning of the direction of propagation of sound waves by mean flow gradients. Parametric studies on the changes in the directivity of radiated sound due to variations in forward flight Mach number and duct mode frequency, azimuthal mode number, and radial mode number are carried out. It is found there is a significant difference in directivity for the radiation of the same duct mode from an engine inlet when operating in static condition and in forward flight. It will be shown that the large change in directivity is the result of the combined effects of diffraction and refraction.

  2. Acoustic and microwave tests in a cylindrical cavity for acoustic gas thermometry at high temperature.

    Zhang, K; Feng, X J; Gillis, K; Moldover, M; Zhang, J T; Lin, H; Qu, J F; Duan, Y N

    2016-03-28

    Relative primary acoustic gas thermometry (AGT) determines the ratios of thermodynamic temperatures from measured ratios of acoustic and microwave resonance frequencies in a gas-filled metal cavity on isotherms of interest. When measured in a cavity with known dimensions, the frequencies of acoustic resonances in a gas determine the speed of sound, which is a known function of the thermodynamic temperature T. Changes in the dimensions of the cavity are measured using the frequencies of the cavity's microwave resonances. We explored techniques and materials for AGT at high temperatures using a cylindrical cavity with remote acoustic transducers. We used gas-filled ducts as acoustic waveguides to transmit sound between the cavity at high temperatures and the acoustic transducers at room temperature. We measured non-degenerate acoustic modes in a cylindrical cavity in the range 295 Kacoustic frequencies increased from 2×10(-6) at 295 K to 5×10(-6) at 797 K. In addition, we measured the frequencies of several transverse magnetic (TM) microwave resonances up to 1000 K in order to track changes in the cavity's length L and radius R. The fractional standard deviation of the values of L deduced from three TM modes increased from 3×10(-6) for T<600 K to 57 × 10(-6) at 1000 K. We observed similar inconsistencies in a previous study. PMID:26903106

  3. Low-cost orbiting grinder for cutting ducts

    Lang, E. J.

    1970-01-01

    Low-cost, portable machine cuts ducts made from heat-treated alloys. An abrasive wheel, powered by a high-speed air motor mounted on an expandible plug against the inner wall of the duct, gives precise cutting.

  4. What Should You Ask Your Doctor about Bile Duct Cancer?

    ... treatment for bile duct cancer? What should you ask your doctor about bile duct cancer? It is ... your own. For instance, you might want to ask about clinical trials for which you may qualify. ...

  5. Solitary intrahepatic bile-duct cyst presenting with Jaundice

    Caroli's disease is an uncommon condition, and characterized by congenital segmental saccular dilatation of intrahepatic bile ducts. A case of Caroli's disease, manifested by only a large communicating cystic dilatation of left intrahepatic bile duct and causing extrinsic pressure over the extrahepatic bile duct, is presented. The patient was 43-year-old housewife, hospitalized because of abdominal distension and severe jaundice. To relieve jaundice and alleviate surgical intervention, percutaneous drainage of the bile-duct cyst preceded surgery

  6. Dust in ventilation ducts : accumulation, measurement and removal

    Holopainen, Rauno

    2004-01-01

    This thesis focuses on dust accumulation in, and removal from, recently installed supply air ducts and on the bristle behaviour of rotating duct cleaning brushes. The results of dust accumulation, measured using three different methods, were compared and the amount of dust in newly installed air ducts was evaluated. The vacuum test was found to be an efficient method of collecting dust samples on the duct surface. The vacuum test and the gravimetric tape method gave approximately the same res...

  7. Idea Bank: Duct Tape Note Twister

    McHenry, Molly

    2008-01-01

    In this article, the author relates how she observed a middle school math teacher deliver a miserable class. She realized that she did the same thing to her music students. To engage her students, she developed "Note Twister," a music reading game using duct tape to form musical notes and the basic premise behind the game, "Twister." She finds…

  8. Detonation duct gas generator demonstration program

    Wortman, Andrew; Brinlee, Gayl A.; Othmer, Peter; Whelan, Michael A.

    1991-01-01

    The feasibility of the generation of detonation waves moving periodically across high speed channel flow is experimentally demonstrated. Such waves are essential to the concept of compressing requirements and increasing the engine pressure compressor with the objective of reducing conventional compressor requirements and increasing the engine thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock wave losses are reduced by an order of magnitude. The ultimate objective is to use such detonation ducts downstream of a low pressure gas turbine compressor to produce a high overall pressure ratio thermodynamic cycle. A 4 foot long, 1 inch x 12 inch cross-section, detonation duct was operated in a blow-down mode using compressed air reservoirs. Liquid or vapor propane was injected through injectors or solenoid valves located in the plenum or the duct itself. Detonation waves were generated when the mixture was ignited by a row of spark plugs in the duct wall. Problems with fuel injection and mixing limited the air speeds to about Mach 0.5, frequencies to below 10 Hz, and measured pressure ratios of about 5 to 6. The feasibility of the gas dynamic compression was demonstrated and the critical problem areas were identified.

  9. IDUS for Biliary and Pancreatic Duct Lesions

    Takao ltoi

    2008-01-01

    @@ In the recent decade, wire-guided intraductal US(IDUS), which can be passed through the working channel of standard duodenoscopes to provide high-frequency ultrasound images, has been developed as a newly diagnostic tool for biliary and pancreatic duct lesions.

  10. Surgical treatment of congenital biliary duct cyst

    Wang De-chun

    2012-03-01

    Full Text Available Abstract Background It is acknowledged that total cyst excision is a safe and ideal surgical treatment for congenital biliary duct cyst, compared to simple internal drainage. The aim of this study was to determine the optimal operation occasion and the effect of laparoscopy on congenital biliary duct cyst based upon total cyst excision. Methods From January 2002 to January 2011, 217 patients were admitted to Southwest Hospital for congenital biliary duct cyst. To determine the optimal surgery occasion, we divided these subjects into three groups, the infant group (age ≤ 3 years, the immaturity group (3 18 years, and then evaluated the feasibility, risk and long-term outcome after surgery in the three groups. To analyze the effect of laparoscopic technique on congenital biliary duct cyst, we divided the patients into the laparoscopy and the open surgery groups. Results Among the three groups, the morbidity from cholangiolithiasis before surgical treatment had obvious discrepancy (p 0.05. Similarly, no significant discrepancy was observed in the morbidity from postoperative complications or long-term postoperative complications (p > 0.05 between the laparoscopic and the open surgery groups. Conclusions We conclude that total cyst excision should be performed as early as possible. The optimal treatment occasion is the infant period, and laparoscopic resection may be a new safe and feasible minimally invasive surgery for this disease.

  11. Calcium influx pathways in rat pancreatic ducts

    Hug, M J; Pahl, C; Novak, I

    1996-01-01

    A number of agonists increase intracellular Ca2+ activity, [Ca2+]i, in pancreatic ducts, but the influx/efflux pathways and intracellular Ca2+ stores in this epithelium are unknown. The aim of the present study was to characterise the Ca2+ influx pathways, especially their pH sensitivity, in nati...

  12. DIFFERENT MULLERIAN DUCT ANOMALIES - DIAGNOSED INCIDENTALLY OR DURING EMERGENCY INTERVENTIONS

    Runa; Kana; Mangal Prasad

    2015-01-01

    INTRODUCTION : Mullerian duct fusion abnormalities result in different reproductive outcomes ranging from multiple uneventful childbirths to ruptures of rudimentary horn during pregnancy. AIMS AND OBJECTIVES : We intended to show the range of reproductive outcomes in different Mullerian duct anomalies . MATERIAL AND METHODS : We included 15 cases with fusion abnormalities of Mullerian ducts diagnosed for the first time while they presented to us, eith...

  13. A case of fascioliasis in common bile duct

    Ham, Soo Youn; Park, Cheol Min; Chung, Kyu Byung; Lee, Chang Hong; Park, Seung Chul; Choi, Sang Yong; Lim, Han Jong [Korea University College of Medicine, Seoul (Korea, Republic of)

    1989-10-15

    A case of Fascioliasis of common bile duct is confirmed by visualization of adult fluke. Fascioliasis caused by Fasciola hepatica, is common parasitic disease in cattle and sheep. Human is an accidental host. ERCP demonstrated irregular linear conglomerated filling defects in common bile duct. Through surgical intervention, we found adult flukes of F. hepatica and adenomatous hyperplasia of common bile duct.

  14. A case of fascioliasis in common bile duct

    A case of Fascioliasis of common bile duct is confirmed by visualization of adult fluke. Fascioliasis caused by Fasciola hepatica, is common parasitic disease in cattle and sheep. Human is an accidental host. ERCP demonstrated irregular linear conglomerated filling defects in common bile duct. Through surgical intervention, we found adult flukes of F. hepatica and adenomatous hyperplasia of common bile duct

  15. Acoustic hemostasis

    Crum, L.; Andrew, M.; Bailey, M.; Beach, K.; Brayman, A.; Curra, F.; Kaczkowski, P.; Kargl, S.; Martin, R.; Vaezy, S.

    2003-04-01

    Over the past several years, the Center for Industrial and Medical Ultrasound (CIMU) at the Applied Physics Laboratory in the University of Washington has undertaken a broad research program in the general area of High Intensity Focused Ultrasound (HIFU). Our principal emphasis has been on the use of HIFU to induce hemostasis; in particular, CIMU has sought to develop a small, lightweight, portable device that would use ultrasound for both imaging and therapy. Such a technology is needed because nearly 50% of combat casualty mortality results from exsanguinations, or uncontrolled bleeding. A similar percentage occurs for civilian death due to trauma. In this general review, a presentation of the general problem will be given, as well as our recent approaches to the development of an image-guided, transcutaneous, acoustic hemostasis device. [Work supported in part by the USAMRMC, ONR and the NIH.

  16. Acoustic telemetry.

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  17. Acoustic Neuroma Educational Video

    Full Text Available Educational Video Home What is an AN What is an Acoustic Neuroma? Identifying an AN Symptoms Acoustic Neuroma Keywords Educational Video ... for pre- and post-treatment acoustic neuroma patients. Home What is an AN What is an Acoustic ...

  18. Heat Transfer in a Superelliptic Transition Duct

    Poinsatte, Philip; Thurman, Douglas; Hippensteele, Steven

    2008-01-01

    Local heat transfer measurements were experimentally mapped using a transient liquid-crystal heat transfer technique on the surface of a circular-to-rectangular transition duct. The transition duct had a length-to-diameter ratio of 1.5 and an exit-plane aspect ratio of 3. The crosssectional geometry was defined by the equation of a superellipse. The cross-sectional area was the same at the inlet and exit but varied up to 15 percent higher through the transition. The duct was preheated to a uniform temperature (nominally 64 C) before allowing room temperature air to be suddenly drawn through it. As the surface cooled, the resulting isothermal contours on the duct surface were revealed using a surface coating of thermochromic liquid crystals that display distinctive colors at particular temperatures. A video record was made of the surface temperature and time data for all points on the duct surfaces during each test. Using this surface temperature-time data together with the temperature of the air flowing through the model and the initial temperature of the model wall, the heat transfer coefficient was calculated by employing the classic one-dimensional, semi-infinite wall heat transfer conduction model. Test results are reported for inlet diameter-based Reynolds numbers ranging from 0.4x106 to 2.4x106 and two grid-generated freestream turbulence intensities of about 1 percent, which is typical of wind tunnels, and up to 16 percent, which may be more typical of real engine conditions.

  19. Use of acoustic vortices in acoustic levitation

    Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller

    2009-01-01

    Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...

  20. International Space Station Crew Quarters Ventilation and Acoustic Design Implementation

    Broyan, James L., Jr.; Cady, Scott M; Welsh, David A.

    2010-01-01

    The International Space Station (ISS) United States Operational Segment has four permanent rack sized ISS Crew Quarters (CQs) providing a private crew member space. The CQs use Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air-from the ISS Common Cabin Air Assembly (CCAA) or the ISS fluid cooling loop. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crew member's head position and reduce acoustic exposure. The CQ ventilation ducts are conduits to the louder Node 2 cabin aisle way which required significant acoustic mitigation controls. The CQ interior needs to be below noise criteria curve 40 (NC-40). The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. Each CQ required 13% of its total volume and approximately 6% of its total mass to reduce acoustic noise. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

  1. Acoustic dispersive prism

    Hussein Esfahlani; Sami Karkar; Herve Lissek; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic ...

  2. The effect of duct surface character on methane explosion propagation

    LIN Bai-quan; YE Qing; JIAN Cong-guang; WU Hai-jin

    2007-01-01

    The effect of duct surface character on methane explosion propagation was experimentally studied and theoretically analyzed. The roughness has effect on methane explosion propagation. The flame propagation velocity and the peak value pressure of methane explosion in rough duct are larger than the parameters in smooth duct. The heat exchange of the surface has effect on methane explosion propagation. The propagation velocity of flame and strength of explosion wave in the duct covered by heat insulation material are larger than those in duct with good heat transmittability.

  3. Transition duct with divided upstream and downstream portions

    McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Maldonado, Jaime Javier; Dillard, Daniel Jackson; Flanagan, James Scott

    2015-07-14

    Turbine systems are provided. In one embodiment, a turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion extending from the inlet and a downstream portion extending from the outlet. The turbine system further includes a rib extending from an outer surface of the duct passage, the rib dividing the upstream portion and the downstream portion.

  4. Dispersion properties of ducted whistlers, generated by lightning discharge

    D. L. Pasmanik

    2005-06-01

    Full Text Available Whistler-mode wave propagation in magnetospheric ducts of enhanced cold plasma density is studied. The case of the arbitrary ratio of the duct radius to the whistler wavelength is considered, where the ray-tracing method is not applicable. The set of duct eigenmodes and their spatial structure are analysed and dependencies of eigenmode propagation properties on the duct characteristics are studied. Special attention is paid to the analysis of the group delay time of one-hop propagation of the whistler wave packet along the duct. We found that, in contrast to the case of a wide duct, the group delay time in a rather narrow duct decreases as the eigenmode number increases. The results obtained are suggested for an explanation of some types of multi-component whistler signals.

  5. Acoustic Neurinomas

    Mohammad Faraji Rad

    2011-01-01

    Full Text Available Acoustic neuromas (AN are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(VS causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumor is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few. The predominant clinical endpoints of AN treatment include tumor control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL. It is uncertain if treating a small tumor leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment.   In this paper we review the literature for the natural course, the treatment alternatives and the results of AN. Finally, we present our experience with a management strategy applied for more than 30 years.

  6. Acoustic Spatiality

    Brandon LaBelle

    2012-06-01

    Full Text Available Experiences of listening can be appreciated as intensely relational, bringing us into contact with surrounding events, bodies and things. Given that sound propagates and expands outwardly, as a set of oscillations from a particular source, listening carries with it a sensual intensity, whereby auditory phenomena deliver intrusive and disruptive as well as soothing and assuring experiences. The physicality characteristic of sound suggests a deeply impressionistic, locational "knowledge structure" – that is, the ways in which listening affords processes of exchange, of being in the world, and from which we extend ourselves. Sound, as physical energy reflecting and absorbing into the materiality around us, and even one's self, provides a rich platform for understanding place and emplacement. Sound is always already a trace of location.Such features of auditory experience give suggestion for what I may call an acoustical paradigm – how sound sets in motion not only the material world but also the flows of the imagination, lending to forces of signification and social structure, and figuring us in relation to each other. The relationality of sound brings us into a steady web of interferences, each of which announces the promise or problematic of being somewhere.

  7. Springer Handbook of Acoustics

    Rossing, Thomas D

    2007-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese...

  8. Responsive acoustic surfaces

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton;

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design for the...... acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design was...... simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  9. Evaporation duct assessment from meteorological buoys

    Hitney, Herbert V.

    2002-07-01

    The evaporation duct over the sea is usually assessed using bulk meteorological measurements. This paper investigates the utility of meteorological buoys as a source for these bulk measurements and compares evaporation duct assessments using two buoys in southern California waters separated by 128 km. A simple radio propagation experiment at 2.4 GHz between one of the buoys and the coast on an 18.2 km path is described. Observed propagation loss from this experiment is compared to modeled loss based on the meteorological measurements at each buoy. The purpose of this paper is to investigate radio propagation effects using established and accepted methods already described in the literature. Accordingly, no discussion of atmospheric surface layer meteorology affecting radio propagation is given.

  10. Whistler wave ducting caused by antenna actions

    Whistler waves launched from an antenna damp away for small incident power. With increasing power, undamped nondiverging waves (the ducted waves) are observed, together with a field-aligned density trough and electron heating. However, the density trough is found not only in the wave propagation regime (ω/ω/sub c/1). This implies that the density depression is mainly created by the effect of the antenna near-zone field rather than by the wave radiation pressure. The intense localized field near the antenna gives rise to electron heating which leads to the density trough. The ducting of antenna-launched whistler waves has been explained as a filamentation instability in terms of nonlinear wave-plasma interactions

  11. Management of Thyroglossal Duct Remnants: Our Experience

    Arunkumar J. S.

    2014-07-01

    Full Text Available Background: Thyroglossal duct remnants are more common in paediatric population. Complete excision of the tract is necessary to prevent recurrence. Sistrunk's surgery is done for thyroglossal duct remnants. This surgery has considerable failure rate. Aims and Objectives: This study was done to present our clinical experience regarding the successful management of thyroglossal cyst and fistula to know the role of imaging in prevention of recurrence after Sisktrunk's surgery. Material and Methods: This is an observational study of 15 cases of thyroglossal cyst and fistula. The data was collected retrospectively from the medical records of SDM College of Medical Sciences and Hospital. Results: No recurrence was seen in this series with a follow up period of 1 year. Conclusion: CT fistulography for thyroglossal fistula and USG neck for thyroglossal cyst is the imaging modality of choice. Nevertheless, it is pivotal to excise a wider core of tissue in revision cases to ensure complete cure to prevent possible recurrence.

  12. Right anterior segmental hepatic duct emptying directly into the cystic duct in a living donor

    Yasunao Ishiguro, Masanobu Hyodo, Takehito Fujiwara, Yasunaru Sakuma, Nobuyuki Hojo, Koichi Mizuta, Hideo Kawarasaki, Alan T Lefor, Yoshikazu Yasuda

    2010-08-01

    Full Text Available A 35-year-old mother was scheduled to be the living donor for liver transplantation to her second son, who suffered from biliary atresia complicated with biliary cirrhosis at the age of 2 years. The operative plan was to recover the left lateral segment of the mother’s liver for living donor transplantation. With the use of cholangiography at the time of surgery, we found the right anterior segmental duct (RASD emptying directly into the cystic duct, and the catheter passed into the RASD. After repairing the incision in the cystic duct, transplantation was successfully performed. Her postoperative course was uneventful. Biliary anatomical variations were frequently encountered, however, this variation has very rarely been reported. If the RASD was divided, the repair would be very difficult because the duct will not dilate sufficiently in an otherwise healthy donor. Meticulous preoperative evaluation of the living donor’s biliary anatomy, especially using magnetic resonance cholangiography and careful intraoperative techniques, is important to prevent bile duct injury and avoid the risk to the healthy donor.

  13. MRI of the biliary and pancreatic ducts

    Pavone, P.; Laghi, A.; Catalano, C.; Panebianco, V.; Fabiano, S.; Passariello, R. [Dept. of Radiology II, Univ. of Rome ``La Sapienza`` (Italy)

    1999-10-01

    Magnetic resonance Cholangiopancreatography (MRCP) is a non-invasive imaging technique able to provide projectional images of the bile ducts. Different sequences, using both breath-hold and non-breath-hold acquisition techniques, have been employed in order to obtain MRCP images. The authors discuss technical aspects, considering both three-dimensional non-breath-hold techniques and two-dimensional breath-hold, multi-slice and thick slab sequences. Clinical applications of MRCP are evaluated, presenting data from both the literature and personal experience. The main indication for MRCP study is represented by the evaluation of common bile duct obstruction, with the aim of assessing the presence of the obstruction (accuracy 85-100 %) and, subsequently, its level (accuracy 91-100 %) and its cause. The utility of associating conventional MR images to MRCP in malignant strictures, in order to characterize and stage the malignant lesion, is also discussed. Finally, data are presented regarding the indications and the utility of MR-pancreatography in the evaluation of patients with pancreatic duct anomalies and chronic pancreatitis. (orig.) With 9 figs., 39 refs.

  14. The transient response above an evaporation duct

    Abo-Seliem, Adel A. S.

    1998-11-01

    The transient electromagnetic field generated by a vertical electric dipole above an evaporation duct is investigated theoretically. The evaporation duct model used is that previously described by Kahan and Eckart. A vertical electric dipole, above the surface layer, is taken as the source of the electromagnetic field. We determine the electrical field strength exactly at some fixed point above the duct layer, having chosen a certain polarization of the primary source whose moment is allowed to vary arbitrarily with time. A series expansion with respect to the images of the primary source permits us to apply the method first reported by Cagniard and later extended by de Hoop and Frankena to the case where the source is positioned in a medium of lesser permittivity. Hence, we can give a physically intuitive description of the polarization dependence of the time history of the electrical field strength. The distinction of different cases where the distances between the receiving and transmitting ends are greater or lesser than the total reflection distance is studied. The electrical field strength is evaluated for different excitation functions at some fixed but arbitrary positions of the point of observation in the half-space.

  15. MR features of common hepatic duct cholangiocarcinoma

    The role of MRI in the detection of cholangiocarcinoma of the common hepatic duct has rarely been described. This study was attempted to ascertain characteristic MR features of cholangiocarcinoma. The T1(500/30, TRs/TEs) and T2 weighted(200/80, TRs/TEs) MR images were obtained from nine patients with cholangiocarcinoma of the common hepatic duct. The common hepatic lesions were detected in seven cases. MR features of cholangiocarcinoma were analysed according to the signal intensity and associated findings. The seven cases showed lower signal intensity than the surrounding normal liver parenchyma on T1 weighted image. On T2 weighted image, the tumor showed isosignal intensity and hyperintensity in four and three patients, respectively. T2 image also revealed diffusely increased signal intensity in some hepatic lobe or segment in four cases, and intrahepatic periductal high signal intensity in one case. Other associated MR findings were intrahepatic metastasis, and intratumoral hemorrhage, each noted in a different case. T2 weighted image appears to be effective in the detection of cholangiocarcinoma of the common hepatic duct and evaluation of its associated intrahepatic lesions

  16. Acoustic source for generating an acoustic beam

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  17. Optimization of air ducts for nuclear reactor power generation station

    In the optimization study on the heating, ventilating and air conditions system in Nuclear Reactor Power Generation Station, proper arrangement of air ducts has been studied using the experimental and analytical investigation from a viewpoint of duct arrangement optimization. This study consists of two parts. Part I is optimization of air ducts in the corridors and Part II is optimization of air duct in each room. In part I, from viewpoints of confinement of radioactive materials in facilities having possible radioactive contamination and improvement of thermal environment for workers, the authors have studied air ducts system in which fresh air is supplied to corridors and heat removal and ventilation for each room are performed by transferring air from the corridors, instead of current ducts system with supply duct to each room. In part II, the condenser room with complex configuration and large space, and the electrical equipment room with simple space are selected for model areas. Based on these studies, experimental and analytical investigation (using a three-dimensional thermal hydraulic analysis) technique has been established, and the effective design method for duct arrangement of HVAC design has been verified for Boiling Water Reactor Power Station. The air-duct arrangements optimized in this study are applied to an Advanced Boiling Water Reactor Power Station in trial and reduction of the air-duct quantity is confirmed

  18. Pronephric duct extension in amphibian embryos: migration and other mechanisms.

    Drawbridge, Julie; Meighan, Christopher M; Lumpkins, Rebecca; Kite, Mary E

    2003-01-01

    Initiation of excretory system development in all vertebrates requires (1) delamination of the pronephric and pronephric duct rudiments from intermediate mesoderm at the ventral border of anterior somites, and (2) extension of the pronephric duct to the cloaca. Pronephric duct extension is the central event in nephric system development; the pronephric duct differentiates into the tubule that carries nephric filtrate out of the body and induces terminal differentiation of adult kidneys. Early studies concluded that pronephric ducts formed by means of in situ segregation of pronephric duct tissue from lateral mesoderm ventral to the forming somites; more recent studies highlight caudal migration of the pronephric duct as the major morphogenetic mechanism. The purpose of this review is to provide the historical background on studies of the mechanisms of amphibian pronephric duct extension, to review evidence showing that different amphibians perform pronephric duct morphogenesis in different ways, and to suggest future studies that may help illuminate the molecular basis of the mechanisms that have evolved in amphibians to extend the pronephric duct to the cloaca. PMID:12508219

  19. Compact Buried Ducts in a Hot-Humid Climate House

    Mallay, Dave [Home Innovation Research Labs, Upper Marlboro, MD (United States)

    2016-01-07

    "9A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely on encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences; 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs; 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.

  20. Idiopathic chylopericardium treated by percutaneous thoracic duct embolization after failed surgical thoracic duct ligation

    Chylopericardium rarely occurs in pediatric patients, but when it does it is most often a result of lymphatic injury during cardiothoracic surgery. Primary idiopathic chylopericardium is especially rare, with few cases in the pediatric literature. We report a 10-year-old boy who presented with primary idiopathic chylopericardium after unsuccessful initial treatment with surgical lymphatic ligation and creation of a pericardial window. Following readmission to the hospital for a right-side chylothorax resulting from the effluent from the pericardial window, he had successful treatment by interventional radiology with percutaneous thoracic duct embolization. This case illustrates the utility of thoracic duct embolization as a less-invasive alternative to surgical thoracic duct ligation, or as a salvage procedure when surgical ligation fails. (orig.)

  1. Idiopathic chylopericardium treated by percutaneous thoracic duct embolization after failed surgical thoracic duct ligation

    Courtney, Malachi; Ayyagari, Raj R. [Yale School of Medicine, Yale New Haven Hospital, New Haven, CT (United States); Division of Interventional Radiology, Department of Radiology, 789 Howard Avenue, P.O. Box 208042, New Haven, CT (United States)

    2015-06-15

    Chylopericardium rarely occurs in pediatric patients, but when it does it is most often a result of lymphatic injury during cardiothoracic surgery. Primary idiopathic chylopericardium is especially rare, with few cases in the pediatric literature. We report a 10-year-old boy who presented with primary idiopathic chylopericardium after unsuccessful initial treatment with surgical lymphatic ligation and creation of a pericardial window. Following readmission to the hospital for a right-side chylothorax resulting from the effluent from the pericardial window, he had successful treatment by interventional radiology with percutaneous thoracic duct embolization. This case illustrates the utility of thoracic duct embolization as a less-invasive alternative to surgical thoracic duct ligation, or as a salvage procedure when surgical ligation fails. (orig.)

  2. Identification of aero-acoustic scattering matrices from large eddy simulation: Application to whistling orifices induct

    The identification of the aero-acoustic scattering matrix of an orifice in a duct is achieved by computational fluid dynamics.The methodology first consists in performing a large eddy simulation of a turbulent compressible flow, with superimposed broadband acoustic excitations. After extracting time series of acoustic data with a specific filter, system identification techniques are applied. They allow us to determine the components of the acoustic scattering matrix of the orifice. Following the same procedure, a previous paper determines the scattering features of a sudden area expansion. In the present paper, the focus is on whistling orifices.The whistling ability of the tested orifice is evaluated by deriving the acoustic power balance from the scattering matrix. Comparisons with experiments at two different Mach numbers show a good agreement.The potential whistling frequency range is well predicted in terms of frequency and amplitude. (authors)

  3. Malignant carcinoid tumor of the cystic duct:a rare cause of bile duct obstruction

    Evangelos Felekouras; Athanasios Petrou; Konstantinos Bramis; Evangelos Prassas; Ioannis Papaconstantinou; Nikoleta Dimitriou; Anastasia Pazaiti; Christos Tsigris; Athanasios Giannopoulos

    2009-01-01

    BACKGROUND: Carcinoid tumors of the extrahepatic biliary tree are extremely rare malignancies, accounting for 0.2%-2%of all gastrointestinal carcinoid tumors, while carcinoids of the cystic duct are an uncommon entity and an extremely unusual cause of bile duct obstruction. METHODS: After an extensive literature review, we retrospectively analysed 61 cases of carcinoid tumor of the biliary tree as well as one additional case of a 60-year-old female with symptoms and laboratory/imaging examination ifndings compatible with those of a malignant biliary tract obstruction. At laparotomy, resection of the gallbladder and common bile duct was performed. Histological study revealed a well-differentiated neuro-endocrine carcinoma of the cystic duct. The patient remained disease-free at 16 months. RESULTS: Our presentation is the seventh case reported in the world literature. Compared to cholangiocarcinoma, analysis of the reviewed group indicates an increased incidence of extrahepatic carcinoid tumors in younger persons along with a slight female predominance. Statistically, the most common anatomic location is the common bile duct, followed by the perihilar region and the cystic duct. Jaundice is the most common ifnding. Curative surgery was realized in the majority of cases and long-term disease-free survival was achieved when surgery was curative. CONCLUSIONS: Carcinoid tumors obstructing the biliary tree are extremely dififcult to diagnose preoperatively, and nearly impossible to differentiate from non-neuroendocrine tumors. As surgery offers the only potential cure for both biliary carcinoids and cholangiocarcinoma, we recommend aggressive surgical therapy as the treatment of choice in every case of potentially resectable biliary tumor.

  4. Acoustic Neuroma Educational Video

    Full Text Available ... Options Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask ... Options Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask ...

  5. Acoustic Neuroma Educational Video

    Full Text Available ... ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Join/Renew ... ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Search ANAUSA. ...

  6. Acoustic Neuroma Educational Video

    Full Text Available ... ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Join/Renew Ways to Give ANA Discussion Forum ... ANA Annual Reports Acoustic Neuroma Legacy Society Programs & Services Search ANAUSA.org Connect with us! Educational Video ...

  7. Cystic acoustic neuromas

    Chitkara, Naveen; Chanda, Rakesh; Yadav, S. P. S.; N.K. Sharma

    2002-01-01

    Predominantly cystic acoustic neuromas are rare and they usually present with clinical and radiological features different from their more common solid counterparts. Two cases of cystic acoustic neuromas are reported here.

  8. Atlantic Herring Acoustic Surveys

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and...

  9. Acoustic Neuroma Educational Video

    Full Text Available ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  10. Acoustic Neuroma Educational Video

    Full Text Available ... is ANA? Mission Statement Board of Directors ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic ... is ANA? Mission Statement Board of Directors ANA Staff Medical Advisory Board News ANA Annual Reports Acoustic ...

  11. Acoustic Neuroma Educational Video

    Full Text Available ... Resources Patient Surveys Related Links Clinical Trials.gov Health Care Insurance Toolkit Additional Resources ANA Public Webinars © 2016 Acoustic Neuroma Association Acoustic Neuroma Association ® • ...

  12. Interposition of the gallbladder - or the absent common hepatic duct and cystic duct

    Interposition of the gallbladder is a rare anomaly, but its diagnosis is important since it represents a surgically correctable cause of jaundice. The patients present with jaundice, abdominal pain and sometimes an enlarged gallbladder. Radiological diagnosis may be difficult since the condition may be mistaken for a choledochal cyst, hydrops of the gallbladder or Caroli's disease. The ultrasound, cholangiogram and surgical findings of dilated intrahepatic ducts adjacent to a normal or enlarged gallbaldder with no dilatation of the common bile duct are presented in two children with this condition. (orig.)

  13. Interposition of the gallbladder - or the absent common hepatic duct and cystic duct

    Stringer, D.A.; Daneman, A.; Dobranowski, J.; Ein, S.H.; Filler, R.M.; Roberts, E.A.

    1987-02-01

    Interposition of the gallbladder is a rare anomaly, but its diagnosis is important since it represents a surgically correctable cause of jaundice. The patients present with jaundice, abdominal pain and sometimes an enlarged gallbladder. Radiological diagnosis may be difficult since the condition may be mistaken for a choledochal cyst, hydrops of the gallbladder or Caroli's disease. The ultrasound, cholangiogram and surgical findings of dilated intrahepatic ducts adjacent to a normal or enlarged gallbaldder with no dilatation of the common bile duct are presented in two children with this condition.

  14. Experimental and analytical studies on aseismic design of ventilation ducts

    For seismic resistant design of the ventilation ducts, it is the most popular and convenient way to idealize duct as a simple beam model and to compute maximum support spacing which makes duct rigid enough. However, few practical data are available to assume the precise stiffness of thinwalled duct on which accurate prediction of dynamic properties depends essentially. In this paper, the experimental study including the vibration tests and the static load tests with regard to two full scale duct models is described and a comparison between experimental and analytical results on the dynamic properties, the deflections and the stress distributions is discussed. Also, the mode of failure of the ducts due to vertically applied static load with negative internal pressure is observed. (orig.)

  15. Sublingual thyroglossal duct cyst (SLTGDC: An unusual location

    Sailesh Mukul

    2016-07-01

    Full Text Available Thyroglossal duct cyst is the most common cause of midline congenital swelling in the neck. Classically, it presents as an asymptomatic midline swelling below the hyoid bone that moves with deglutination and protrusion of the tongue. Sometimes thyroglossal duct cyst presents atypical posing a diagnostic challenge. A sublingual location of thyroglossal duct cyst is rare, and differs quite remarkably in presentation from the classical thyroglossal duct cyst. We describe here the case of a young boy who presented with episodes of postural dyspnea due to elevation of the tongue which was secondary to huge sublingual swelling. Surgical decompression of the lesion was planned on an emergency basis with feasible preoperative workup. The aim of this case report is to highlight the unique presentation and a varied approach in the management of an unusually located sublingual thyroglossal duct cyst. Sublingual/intralingual thyroglossal duct cyst needs to be analyzed in a larger study population for establishing definitive management protocols.

  16. Climate analysis of evaporation ducts in the South China Sea

    McKeon, Brian D.

    2013-01-01

    Approved for public release; distribution is unlimited. Evaporation ducts have important implications for U.S. Naval activities involving electromagnetic propagation. The presence of an evaporation duct can affect naval operations involving communications, surveillance, electronic warfare, and detection of low-flying missiles, surface ships, or submarine periscopes. We conducted a climate scale analysis of evaporation duct heights (EDH) in the northern South China Sea (SCS), including how ...

  17. Solitary intrahepatic bile-duct cyst presenting with Jaundice

    Park, Jeong Mi; Chun, Ki Sung; Ha, Hyun Kwon; Shinn, Kyung Sub; Bahk, Yong Whee; Kim, Jun Gi [St. Vincent Hospital, Catholic University Medical College, Seoul (Korea, Republic of)

    1989-08-15

    Caroli's disease is an uncommon condition, and characterized by congenital segmental saccular dilatation of intrahepatic bile ducts. A case of Caroli's disease, manifested by only a large communicating cystic dilatation of left intrahepatic bile duct and causing extrinsic pressure over the extrahepatic bile duct, is presented. The patient was 43-year-old housewife, hospitalized because of abdominal distension and severe jaundice. To relieve jaundice and alleviate surgical intervention, percutaneous drainage of the bile-duct cyst preceded surgery.

  18. Leaf seal for transition duct in turbine system

    Flanagan, James Scott; LeBegue, Jeffrey Scott; McMahan, Kevin Weston; Dillard, Daniel Jackson; Pentecost, Ronnie Ray

    2013-06-11

    A turbine system is disclosed. In one embodiment, the turbine system includes a transition duct. The transition duct includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct further includes an interface member for interfacing with a turbine section. The turbine system further includes a leaf seal contacting the interface member to provide a seal between the interface member and the turbine section.

  19. Flexible metallic seal for transition duct in turbine system

    Flanagan, James Scott; LeBegue, Jeffrey Scott; McMahan, Kevin Weston; Dillard, Daniel Jackson; Pentecost, Ronnie Ray

    2014-04-22

    A turbine system is disclosed. In one embodiment, the turbine system includes a transition duct. The transition duct includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct further includes an interface member for interfacing with a turbine section. The turbine system further includes a flexible metallic seal contacting the interface member to provide a seal between the interface member and the turbine section.

  20. Advances of MRCP in diagnosis of pancreatic duct dilatation

    Pancreatic duct dilatation is a common sign of pancreaticobiliary diseases and may be seen in pancreatic carcinoma, carcinoma of duodenal papilla, distal common bile duct carcinoma, ampullary carcinoma, intraductal papillary mucinous tumor, pancreatitis, pancreatic pseudocyst, sphincter of oddi dysfunction, pancreatic trauma, pancreas divisum, annular pancreas, pancreatic tuberculosis, abdominal aorta aneurysm, etc. It is possible to make a correct diagnosis and differential diagnosis by analyzing features of shape, extent, and location of dilated pancreatic duct. This article reviews the advances of MRCP in etiological diagnosis of dilatation of the pancreatic duct. (authors)

  1. Duct injection technology prototype development: Evaluation of engineering data

    1990-07-01

    The objective of the Duct Injection Technology Prototype Development Project is to develop a sound design basis for applying duct injection technology as a post-combustion SO{sub 2}emissions control method to existing coal-fired power plants. The necessary engineering design and scale-up criteria will be developed for the commercialization of duct injection technology for the control of SO{sub 2} emissions from coal-fired boilers in the utility industry. The primary focus of the analyses summarized in this Topical Report is the review of the known technical and economic information associated with duct injection technology. (VC)

  2. Occlusion of the cystic duct by electrocoagulation: A radiologic technique

    Chemical dissolution and extracorporeal shock wave lithotripsy are promising new methods for the treatment of cholelithiasis without cholecystectomy. Nonsurgical defunctionalization of the gallbladder is now required to prevent recurrent stone formation. The authors consider cystic duct occlusion to be the first step. Ten domestic pigs underwent transcatheter electrocoagulation of the cystic duct via a cholecystostomy under fluoroscopic control. Stricture formation was followed by complete cystic duct occlusion in all ten cases. After a follow-up period ranging from 2 to 17 weeks (mean, 13 weeks), the animals were killed. Histologic studies demonstrated that complete obliteration of the cystic duct lumen was due to fibrous scar formation

  3. Method for Observing Intravascular BongHan Duct

    Jiang, X; Shin, H; Lee, B; Choi, C; Soh, K; Cheun, B; Baik, K; Soh, K; Jiang, Xiaowen; Kim, Hee-kyeong; Shin, Hak-soo; Lee, Byong-chon; Choi, Chunho; Soh, Kyung-soon; Cheun, Byeung-soo; Baik, Ku-youn; Soh, Kwang-sup

    2002-01-01

    A method for observing intra blood vessel ducts which are threadlike bundle of tubules which form a part of the BongHan duct system. By injecting 10% dextrose solution at a vena femoralis one makes the intravascular BongHan duct thicker and stronger to be easily detectable after incision of vessels. The duct is semi-transparent, soft and elastic, and composed of smaller tubules whose diameters are of 10$\\mu$m order, which is in agreement with BongHan theory.

  4. Digital subtraction angiography in the open arterial duct

    Digital subtraction angiography (DSA) was performed in 31 patients with the open arterial duct (OAD), of them 15 were outpatients. Diagnosis was made in all primary patients using DSA, indications and contraindications for endovascular occlusion of the OAD were defined. Of 17 patients examined at varying time after endovascular occlusion of the duct, valid signs of reliable occlusion of the duct were obtained in 16. In one patient a contrast medium got from the aorta to the pulmonary artery via the arterial duct indicating OAD incomplete closure. DSA can be used under uotpatient conditions to define indications and contraindications for endovascular occlusion of the OAD and to assess its long-term effectiveness

  5. Thyroglossal duct cysts: sonographic findings revisited

    The purpose of this study was to review and re-evaluate the well-known ultrasonographic characteristics of cysts of the thyroglossal duct. We retrospectively reviewed the ultrasonographic findings in 31 patients with pathologically proven cysts of the thyloglossal duct. Assessment involve the following variables: relationship to the hyoid bone,location,shape,size,margin,internal echogenicity,the presence of septa,solid component,and thickness of the cystic wall. The echogenicity of cystic contents was evaluated in 23 cysts for which surgical or aspiration biopsy reports were available.Cysts were closely attached to the hyoid bone in 30 cases (97%). Their location was infrahyoid in 14 cases, hyoid in 11, and surprahyoid in six; and midline in 18, both midline and of-midline in nine, and off-midline in four. A triangular shape was seen in 15 cases ,a round or oval shape in 12, and a lobulated shape in three. Their diameter varied from 1 to 3.8 (mean,2) cm, while internal echogenicity was hypoechoic in 12 cases, anechoic in ten, and isoechoic in nine. Septations were noted in six cases, and a solid component in two.The cystic wall was less than 1mm in six. Among 23 cases, the cystic contents were mucous in 18, serous in three , and purulent in two. The echogenicity of cysts with mucous content varied,while serous or purolent cysts were isoechoic. The characteristic sonographic finding of cyst of the thyroglossal duct is a centrally located triangular neck cyst, closely related to the hyoid bone

  6. Thyroglossal duct cysts: sonographic findings revisited

    Kim, Sun Mi; Lee, Kyu Ho; Yoon, Jong Hyun; Shin, Ji Hoon; Choi, Choong Gon; Shu, Dae Chul; Kim, Sang Yoon [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-01-01

    The purpose of this study was to review and re-evaluate the well-known ultrasonographic characteristics of cysts of the thyroglossal duct. We retrospectively reviewed the ultrasonographic findings in 31 patients with pathologically proven cysts of the thyloglossal duct. Assessment involve the following variables: relationship to the hyoid bone,location,shape,size,margin,internal echogenicity,the presence of septa,solid component,and thickness of the cystic wall. The echogenicity of cystic contents was evaluated in 23 cysts for which surgical or aspiration biopsy reports were available.Cysts were closely attached to the hyoid bone in 30 cases (97%). Their location was infrahyoid in 14 cases, hyoid in 11, and surprahyoid in six; and midline in 18, both midline and of-midline in nine, and off-midline in four. A triangular shape was seen in 15 cases ,a round or oval shape in 12, and a lobulated shape in three. Their diameter varied from 1 to 3.8 (mean,2) cm, while internal echogenicity was hypoechoic in 12 cases, anechoic in ten, and isoechoic in nine. Septations were noted in six cases, and a solid component in two.The cystic wall was less than 1mm in six. Among 23 cases, the cystic contents were mucous in 18, serous in three , and purulent in two. The echogenicity of cysts with mucous content varied,while serous or purolent cysts were isoechoic. The characteristic sonographic finding of cyst of the thyroglossal duct is a centrally located triangular neck cyst, closely related to the hyoid bone.

  7. [Liver, bile ducts and pancreatic diseases].

    Kanno, T

    1995-06-01

    A fundamental guideline for the use of test results concerning liver, bile duct and pancreatic diseases was proposed in 1991 from the Japan Society of Clinical Pathology (JSCP). This guideline was principally based on the document of 1988 from the Committee on liver function tests of the Japanese Society of Gastroenterology (JSG). The document from the JSG was revised in May, 1994. Also a guideline for selection of markers of hepatitis virus in hepatic disorders, was proposed in January, 1994 from the same Committee of JSG. Here, we reevaluated and discussed the JSCP guideline as taking into consideration the two 1994 JSG documents. PMID:7602802

  8. Anatomy of the nipple and breast ducts.

    Zucca-Matthes, Gustavo; Urban, Cícero; Vallejo, André

    2016-02-01

    Over time, variations of mastectomy came up and started allowing the oncological safety and the possibility of an immediate breast reconstruction. Nipple sparing mastectomy (NSM) procedures have strongly increased in frequency and have become one of the best alternatives to treat breast cancer, also improving overall aesthetic outcomes and the achievement of contralateral breast symmetry. The nipple areola-complex (NAC) must be considered the identity of the breast concerning self-esteem of patients. This paper will remind the main anatomical topics around the nipple and breast ducts. PMID:26855906

  9. MULLERIAN DUCT ANOMALY: A CASE REPORT

    Sunny

    2014-11-01

    Full Text Available The frequency of mullerian duct anomalies vary widely owing to different patient populations, non-standardized classification systems, and differences in diagnostic data acquisition, these anomalies are clinically important, particularly in women who present with infertility. Many of the anomalies are initially diagnosed at hysterosalpingography and ultrasonography; however, further imaging is often required for definitive diagnosis and elaboration of secondary findings. At this time, magnetic resonance imaging is the study of choice because of its high accuracy and detailed elaboration of uterovaginal anatomy. Here, we report a case of 30 years old female who presented to emergency department with bad obstetric history.

  10. Clinical significance of main pancreatic duct dilation on computed tomography: Single and double duct dilation

    Edge, Mark D; Hoteit, Maarouf; Patel, Amil P; Wang, Xiaoping; Baumgarten, Deborah A.; Cai, Qiang

    2007-01-01

    AIM: To study the patients with main pancreatic duct dilation on computed tomography (CT) and thereby to provide the predictive criteria to identify patients at high risk of significant diseases, such as pancreatic cancer, and to avoid unnecessary work up for patients at low risk of such diseases.

  11. International Space Station USOS Crew Quarters Ventilation and Acoustic Design Implementation

    Broyan, James Lee, Jr.

    2009-01-01

    The International Space Station (ISS) United States Operational Segment (USOS) has four permanent rack sized ISS Crew Quarters (CQ) providing a private crewmember space. The CQ uses Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air from the ISS Temperature Humidity Control System or the ISS fluid cooling loop connections. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crewmember s head position and reduce acoustic exposure. The CQ interior needs to be below Noise Curve 40 (NC-40). The CQ ventilation ducts are open to the significantly louder Node 2 cabin aisle way which required significantly acoustic mitigation controls. The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

  12. ACOUSTICAL STANDARDS NEWS.

    Blaeser, Susan B; Struck, Christopher J

    2016-03-01

    American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, S3/SC 1, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, animal bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes a catalog of Acoustical American National Standards. To receive a copy of the latest Standards catalog, please contact Susan B. Blaeser.Comments are welcomed on all material in Acoustical Standards News.This Acoustical Standards News section in JASA, as well as the National Catalog of Acoustical Standards and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org. PMID:27036268

  13. Seasonal variations of surface duct conditions in Ngaoundere, North Cameroon

    Kaissassou, Samuel; Lenouo, André; Nzeukou, Armand; Tchawoua, Clément; Vondou, D. A.

    2015-12-01

    The seasonal variations of refractivity gradients from 104 to 3000 m above ground level in the troposphere layer are presented based on observations from the radiosonde station located in Ngaoundere (13.5°E, 7.3°N), a middle belt savannah region of Cameroon. Six years (2006-2011) of data from in situ measurements made by Agency for the Safety of Air Navigation in Africa and Madagascar (ASECNA) of the temperature, moisture, and pressure are used to determine the surface duct conditions over Ngaoundere region. Each time that a negative gradient from the Abel-retrieved refractivity profiles is seen, it implies the presence of a duct in this study. The occurrence of ducts strongly depends on the local climate and synoptic weather conditions which have an appreciable influence on the refractivity vertical profile, especially the seasonal north-south movement of the Inter Tropical Convergence Zone (ITCZ) which provides wet and dry seasons to the region. Monthly and seasonal variations of ducts were also determined from the measured data. The highest and the lowest occurrence rate of surface ducts were observed during the wet and the dry seasons, respectively. September appears as the month when most of the ducts occur at the rate of at least one duct per day. The median duct thickness and duct strength are high and strong during the wet season, whereas they are low and weak during the dry season. When the data are separated into stable and unstable atmospheric conditions, we noticed that surface duct characteristics show some seasonal differences. Surface ducts are found to be more frequent in a stable atmosphere than in an unstable atmosphere. Statistical results are discussed alongside with local meteorological conditions and weather systems affecting the town of Ngaoundere. Besides, comments are made on their prospective significance in the region.

  14. Evaporation duct effects at millimeter wavelengths

    Anderson, K. D.

    1992-03-01

    The evaporation duct strongly influences low-altitude over-the-horizon propagation at millimeter wavelengths. Results from more than 2000 hours of propagation and meteorological measurements made at 94 GHz on a 40.6 km over-horizon, over-water path along the southern California coast show that the average received power was 63 dB greater than d for propagation in a nonducting, or standard, atmosphere; 90 percent of the measurements were at least 55 dB greater than diffraction. A numerical model of transmission loss based on the observed surface meteorology is discussed and results are compared to measured transmission loss. On average, modeling results underestimate observations by only 10 dB. In addition, results from modeling based on an independent climatology of evaporation duct heights for the area are shown to be adequate for most propagation assessment purposes. The reliability and reasonable accuracy of the numerical model provides a strong justification for utilizing the technique to assess millimeter wave communication and radar systems operating in many, if not all, ocean regions.

  15. Finite-difference lattice Boltzmann simulation on acoustics-induced particle deposition

    Fu, Sau-Chung; Yuen, Wai-Tung; Wu, Chili; Chao, Christopher Yu-Hang

    2015-10-01

    Particle manipulation by acoustics has been investigated for many years. By a proper design, particle deposition can be induced by the same principle. The use of acoustics can potentially be developed into an energy-efficient technique for particle removal or filtration system as the pressure drop due to acoustic effects is low and the flow velocity is not necessary to be high. Two nonlinear acoustic effects, acoustic streaming and acoustic radiation pressure, are important. Acoustic streaming introduces vortices and stagnation points on the surface of an air duct and removes the particles by deposition. Acoustic radiation pressure causes particles to form agglomerates and enhances inertial impaction and/or gravitational sedimentation. The objective of this paper is to develop a numerical model to investigate the particle deposition induced by acoustic effects. A three-step approach is adopted and lattice Boltzamnn technique is employed as the numerical method. This is because the lattice Boltzmann equation is hyperbolic and can be solved locally, explicitly, and efficiently on parallel computers. In the first step, the acoustic field and its mean square fluctuation values are calculated. Due to the advantage of the lattice Boltzmann technique, a simple, stable and fast lattice Boltzmann method is proposed and verified. The result of the first step is input into the second step to solve for acoustic streaming. Another finite difference lattice Boltzmann method, which has been validated by a number of flows and benchmark cases in the literature, is used. The third step consists in tracking the particle's motion by a Lagrangian approach where the acoustic radiation pressure is considered. The influence of the acoustics effects on particle deposition is explained. The numerical result matches with an experiment. The model is a useful tool for optimizing the design and helps to further develop the technique.

  16. Advanced Nacelle Acoustic Lining Concepts Development

    Bielak, G.; Gallman, J.; Kunze, R.; Murray, P.; Premo, J.; Kosanchick, M.; Hersh, A.; Celano, J.; Walker, B.; Yu, J.; Parrott, Tony L. (Technical Monitor)

    2002-01-01

    The work reported in this document consisted of six distinct liner technology development subtasks: 1) Analysis of Model Scale ADP Fan Duct Lining Data (Boeing): An evaluation of an AST Milestone experiment to demonstrate 1995 liner technology superiority relative to that of 1992 was performed on 1:5.9 scale model fan rig (Advanced Ducted Propeller) test data acquired in the NASA Glenn 9 x 15 foot wind tunnel. The goal of 50% improvement was deemed satisfied. 2) Bias Flow Liner Investigation (Boeing, VCES): The ability to control liner impedance by low velocity bias flow through liner was demonstrated. An impedance prediction model to include bias flow was developed. 3) Grazing Flow Impedance Testing (Boeing): Grazing flow impedance tests were conducted for comparison with results achieved at four different laboratories. 4) Micro-Perforate Acoustic Liner Technology (BFG, HAE, NG): Proof of concept testing of a "linear liner." 5) Extended Reaction Liners (Boeing, NG): Bandwidth improvements for non-locally reacting liner were investigated with porous honeycomb core test liners. 6) Development of a Hybrid Active/Passive Lining Concept (HAE): Synergism between active and passive attenuation of noise radiated by a model inlet was demonstrated.

  17. Congenital bile duct dilatation (Caroli's disease - Grumbach's disease)

    Congenital bile duct dilatation is an autosomal recessive inherited disease. Pathologically tortuous dilated, dyplastic intrahepatic bile ducts were found. It may be associated with hepatic fibrosis (Grumbach's disease), or without (Caroli's disease). A common additional finding is an infantile polycystic kidney. Three cases are reported and the radiological and sonographic findings are discussed. (orig.)

  18. What Are the Risk Factors for Bile Duct Cancer?

    ... What are the risk factors for bile duct cancer? A risk factor is anything that affects your chance of getting ... to top » Guide Topics What Is Bile Duct Cancer? Causes, Risk Factors, and Prevention Early Detection, Diagnosis, and Staging Treating ...

  19. Bidirectional infrasonic ducts associated with sudden stratospheric warming events

    Assink, J.D.; Waxler, R.; Smets, P.S.M.; Evers, L.G.

    2014-01-01

    In January 2011, the state of the polar vortex in the midlatitudes changed significantly due to a minor sudden stratospheric warming event. As a result, a bidirectional duct for infrasound propagation developed in the middle atmosphere that persisted for 2 weeks. The ducts were due to two zonal wind

  20. Chloride and potassium conductances of cultured human sweat ducts

    Novak, I; Pedersen, P S; Larsen, Erik Hviid

    1992-01-01

    The purpose of this study was to characterize the ion conductances, in particular those for Cl- and K+, of human sweat duct cells grown in primary culture. Sweat duct cells from healthy individuals were grown to confluence on a dialysis membrane, which was then mounted in a mini-Ussing chamber and...

  1. Do We Know What Causes Bile Duct Cancer?

    ... Topic Can bile duct cancer be prevented? Do we know what causes bile duct cancer? We don’t know the exact cause of most ... genes – the instructions for how our cells function. We usually look like our parents because they are ...

  2. Seismic assessment of the Pickering pressure relief duct

    The objectives of the study are to examine the structural response of the Pickering pressure relief duct when subjected to earthquake ground motion and to estimate the seismic withstand capacity of various components of the structural system on the basis of performance criteria consistent with the safety function of the duct. (author). 24 refs., 16 tabs., 31 figs

  3. Cystic duct closure by sealing with bipolar electrocoagulation

    Schulze, S; Damgaard, B; Jørgensen, Lars Nannestad; Larsen, S S; Kristiansen, V B

    2010-01-01

    BACKGROUND: Cystic duct leakage after cholecystectomy is not uncommon and is a potentially serious complication. The aim of this study was to assess a bipolar sealing system (LigaSure) for closure of the cystic duct. METHODS: The records from consecutive laparoscopic cholecystectomies performed in...

  4. AST Launch Vehicle Acoustics

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  5. A boundary element model for lined circular ducts with uniform flow

    Juhl, Peter Møller

    1996-01-01

    application the prediction of attenuation at very high frequencies (up to ka=30) is important. However, it was found that the computational costs of a three-dimensional model would by far exceed the performance of a normal workstation. Therefore, an axisymmetric model with significantly reduced calculation...... time and storage requirements has been developed, and the model has been extended with a new formulation to allow for non-axisymmetric excitation. These co-called spinning modes are very important for the application to aeroacoustics. Another innovation of this work is the development of an iterative......A boundary element method has been developed for predicting the acoustics in a circular duct in which a uniform flow propagates. Such a model may be used to predict the performance of different liner designs for inlets of turbo fan engines, which is important for the aeronautics industry. For this...

  6. A mapped finite difference study of noise propagation in nonuniform ducts with mean flow

    Raad, Peter E.; White, James W.

    1987-01-01

    The primary objective of this work is to study noise propagation in acoustically lined variable area ducts with mean fluid flow. The method of study is numerical in nature and involves a body-fitted grid mapping procedure in conjunction with a factored-implicit finite difference technique. The mean fluid flow model used is two-dimensional, inviscid, irrotational, incompressible, and nonheat conducting. Fully-coupled solutions of the linearized gasdynamic equations are obtained for both positive and negative Mach numbers as well as for hard and soft wall conditions. The factored-implicit finite difference technique used did give rise to short wavelength perturbations, but these were dampened by the introduction of higher order artificial dissipation terms into the scheme. Results compared favorably with available numerical and experimental data.

  7. Duct thermal performance models for large commercial buildings

    Wray, Craig P.

    2003-10-01

    Despite the potential for significant energy savings by reducing duct leakage or other thermal losses from duct systems in large commercial buildings, California Title 24 has no provisions to credit energy-efficient duct systems in these buildings. A substantial reason is the lack of readily available simulation tools to demonstrate the energy-saving benefits associated with efficient duct systems in large commercial buildings. The overall goal of the Efficient Distribution Systems (EDS) project within the PIER High Performance Commercial Building Systems Program is to bridge the gaps in current duct thermal performance modeling capabilities, and to expand our understanding of duct thermal performance in California large commercial buildings. As steps toward this goal, our strategy in the EDS project involves two parts: (1) developing a whole-building energy simulation approach for analyzing duct thermal performance in large commercial buildings, and (2) using the tool to identify the energy impacts of duct leakage in California large commercial buildings, in support of future recommendations to address duct performance in the Title 24 Energy Efficiency Standards for Nonresidential Buildings. The specific technical objectives for the EDS project were to: (1) Identify a near-term whole-building energy simulation approach that can be used in the impacts analysis task of this project (see Objective 3), with little or no modification. A secondary objective is to recommend how to proceed with long-term development of an improved compliance tool for Title 24 that addresses duct thermal performance. (2) Develop an Alternative Calculation Method (ACM) change proposal to include a new metric for thermal distribution system efficiency in the reporting requirements for the 2005 Title 24 Standards. The metric will facilitate future comparisons of different system types using a common ''yardstick''. (3) Using the selected near-term simulation approach

  8. Consistent approach to air-cleaning system duct design

    Nuclear power plant air-cleaning system effectiveness is dependent on the capability of a duct system to safely convey contaminated gas to a filtration unit and subsequently to a point of discharge. This paper presents a logical and consistent design approach for selecting sheet metal ductwork construction to meet applicable criteria. The differences in design engineers' duct construction specifications are acknowledged. Typical duct construction details and suggestions for their effective use are presented. Improvements in duct design sections of ANSI/ASME N509-80 are highlighted. A detailed leakage analysis of a control room HVAC system is undertaken to illustrate the effects of conceptual design variations on duct construction requirements. Shortcomings of previously published analyses and interpretations of a current standard are included

  9. Role of endoscopic ultrasound in common bile duct stones

    Aljebreen Abdulrahman

    2007-01-01

    Full Text Available When the clinical features strongly suggest the presence of bile duct stones, management is fairly straightforward; diagnostic and therapeutic endoscopic retrograde cholangiography (ERC may in some cases constitute the entire strategy. Unfortunately, the clinical picture is often equivocal or uncertain. Although stones are unlikely to be present in the bile duct when the clinical index of suspicion is low, their presence can never be completely ruled out based on clinical and biochemical parameters. Thus, an accurate, noninvasive, reliable, and safe method for bile duct imaging would be highly advantageous. Low-risk tests, such as endoscopic ultrasound (EUS, are emerging as reliable substitutes for diagnostic ERC. This review highlights the technical aspects of examining the extra-hepatic biliary duct system and the performance and results of EUS in diagnosing patients who present with possible common bile duct stones.

  10. A new evaporation duct climatology over the South China Sea

    Shi, Yang; Yang, Kunde; Yang, Yixin; Ma, Yuanliang

    2015-10-01

    The climatology of evaporation ducts is important for shipborne electromagnetic system design and application. The evaporation duct climatology that is currently used for such applications was developed in the mid 1980s; this study presents efforts to improve it over the South China Sea (SCS) by using a state-of-the-art evaporation duct model and an improved meteorology dataset. This new climatology provides better evaporation duct height (EDH) data over the SCS, at a higher resolution of 0.312°×0.313°. A comparison between the new climatology and the old one is performed. The monthly average EDH in the new climatology is between 10 and 12 m over the SCS, higher than that in the old climatology. The spatiotemporal characteristics of the evaporation duct over the SCS in different months are analyzed in detail, based on the new climatology.

  11. Cystic duct remnant mucocele in a liver transplant recipient

    Ahlawat, Sushil K. [Georgetown University Hospital, Department of Medicine, Division of Gastroenterology, Washington, DC (United States); University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ (United States); Fishbien, Thomas M. [Georgetown University Hospital, Department of Medicine, Division of Gastroenterology, Washington, DC (United States); Haddad, Nadim G. [Georgetown University Hospital, Department of Surgery, Division of Transplant Surgery, Washington, DC (United States)

    2008-08-15

    Cystic duct remnant mucocele is an extremely rare complication of liver transplantation in children. Surgical correction is usually required for cystic duct remnant mucocele when it causes biliary obstruction. We describe a 14-month-old liver transplant recipient who presented with biliary obstruction 1 month after orthotopic liver transplantation with an end-to-end choledochocholedocal biliary anastomosis for hepatoblastoma. US, CT and cholangiography findings were consistent with mucocele of the allograft cystic duct remnant. Surgery was not needed in our patient because the mucocele and biliary obstruction had resolved on repeat imaging most likely due to guidewire manipulation during cholangiography, resulting in opening of the cystic duct remnant orifice and drainage into the common duct. (orig.)

  12. Cystic duct remnant mucocele in a liver transplant recipient

    Cystic duct remnant mucocele is an extremely rare complication of liver transplantation in children. Surgical correction is usually required for cystic duct remnant mucocele when it causes biliary obstruction. We describe a 14-month-old liver transplant recipient who presented with biliary obstruction 1 month after orthotopic liver transplantation with an end-to-end choledochocholedocal biliary anastomosis for hepatoblastoma. US, CT and cholangiography findings were consistent with mucocele of the allograft cystic duct remnant. Surgery was not needed in our patient because the mucocele and biliary obstruction had resolved on repeat imaging most likely due to guidewire manipulation during cholangiography, resulting in opening of the cystic duct remnant orifice and drainage into the common duct. (orig.)

  13. Extravasation Mucocele Arising from a Lingual Thyroglossal Duct Remnant

    Mitsuhiko Nakahira

    2015-01-01

    Full Text Available Although a thyroglossal duct cyst is a congenital anomaly, it can also appear in adults. Despite the presence of embryological remnants, it is still unclear why the cyst should suddenly develop later in life. We report a case of a 46-year-old male with an extravasation mucocele arising from a long-standing lingual thyroglossal duct remnant. MRI demonstrated a lingual cystic lesion near the hyoid bone associated with a suprahyoid tract-like structure masquerading as a thyroglossal duct cyst. However, histopathological examination demonstrated a mucocele secondary to a rupture of a thyroglossal duct remnant with numerous intramural heterotopic salivary glands. We propose a new mechanism of an acquired cystic formation of this congenital disease that excessive production of mucus from heterotopic salivary glands and a physical trauma such as swallowing may lead to extravasation of mucus from the thyroglossal duct.

  14. Experimental methodology for turbocompressor in-duct noise evaluation based on beamforming wave decomposition

    Torregrosa, A. J.; Broatch, A.; Margot, X.; García-Tíscar, J.

    2016-08-01

    An experimental methodology is proposed to assess the noise emission of centrifugal turbocompressors like those of automotive turbochargers. A step-by-step procedure is detailed, starting from the theoretical considerations of sound measurement in flow ducts and examining specific experimental setup guidelines and signal processing routines. Special care is taken regarding some limiting factors that adversely affect the measuring of sound intensity in ducts, namely calibration, sensor placement and frequency ranges and restrictions. In order to provide illustrative examples of the proposed techniques and results, the methodology has been applied to the acoustic evaluation of a small automotive turbocharger in a flow bench. Samples of raw pressure spectra, decomposed pressure waves, calibration results, accurate surge characterization and final compressor noise maps and estimated spectrograms are provided. The analysis of selected frequency bands successfully shows how different, known noise phenomena of particular interest such as mid-frequency "whoosh noise" and low-frequency surge onset are correlated with operating conditions of the turbocharger. Comparison against external inlet orifice intensity measurements shows good correlation and improvement with respect to alternative wave decomposition techniques.

  15. Vibro-acoustics

    Nilsson, Anders

    2015-01-01

    This three-volume book gives a thorough and comprehensive presentation of vibration and acoustic theories. Different from traditional textbooks which typically deal with some aspects of either acoustic or vibration problems, it is unique of this book to combine those two correlated subjects together. Moreover, it provides fundamental analysis and mathematical descriptions for several crucial phenomena of Vibro-Acoustics which are quite useful in noise reduction, including how structures are excited, energy flows from an excitation point to a sound radiating surface, and finally how a structure radiates noise to a surrounding fluid. Many measurement results included in the text make the reading interesting and informative. Problems/questions are listed at the end of each chapter and the solutions are provided. This will help the readers to understand the topics of Vibro-Acoustics more deeply. The book should be of interest to anyone interested in sound and vibration, vehicle acoustics, ship acoustics and inter...

  16. Springer handbook of acoustics

    2014-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and electronics. The Springer Handbook of Acoustics is also in his 2nd edition an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents. This new edition of the Handbook features over 11 revised and expanded chapters, new illustrations, and 2 new chapters covering microphone arrays  and acoustic emission.  Updated chapters contain the latest research and applications in, e.g. sound propagation in the atmosphere, nonlinear acoustics in fluids, building and concert hall acoustics, signal processing, psychoacoustics, computer music, animal bioacousics, sound intensity, modal acoustics as well as new chapters on microphone arrays an...

  17. Acoustic streaming in microchannels

    Tribler, Peter Muller

    , and experimental results for the streaming-induced drag force dominated motion of particles suspended in a water-filled microchannel supporting a transverse half-wavelength resonance. The experimental and theoretical results agree within a mean relative dierence of approximately 20%, a low deviation given state......This thesis presents studies of boundary-driven acoustic streaming in microfluidic channels, which is a steady flow of the fluid initiated by the interactions of an oscillating acoustic standing wave and the rigid walls of the microchannel. The studies present analysis of the acoustic resonance......, the acoustic streaming flow, and the forces on suspended microparticles. The work is motivated by the application of particle focusing by acoustic radiation forces in medical, environmental and food sciences. Here acoustic streaming is most often unwanted, because it limits the focusability of particles...

  18. Hollow-duct radiation delivery system investigation

    Fibrich, Martin; Rus, Bedřich; Kramer, Daniel

    Praha : IPP AS CR - TOPTEC, 2012 - (Vít, T.; Kovačičinová, J.; Lédl, V.), 13-16 ISBN 978-80-87026-02-1. [OaM 2012 International Conference on Optics and Measurement. Liberec (CZ), 16.10.2012-18.10.2012] R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE.2.3.20.0091 Grant ostatní: ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OP VK 1 LaserSys(XE) CZ.1.07/2.3.00/20.0091 Institutional support: RVO:68378271 Keywords : laser * diode-array-radiation * hollow -duct radiation Subject RIV: BH - Optics, Masers, Lasers

  19. PERSISTENT MULLERIAN DUCT SYNDROME: A CASE REPORT

    Siddalingeshwar V

    2014-11-01

    Full Text Available : A 3-year-old boy presenting with right inguinal hernia was found to have uterus, fallopian tube and testes in a position analogous to ovaries in hernial sac, warranting a diagnosis of persistent Mullerian duct syndrome (PMDS. PMDS is an extremely rare form of internal male pseudo-hermaphroditism in which female internal sex organs, including the uterus, cervix and proximal vagina, persist in a 46XY male with normal external genitalia. The condition results from a congenital insensitivity to anti-Mullerian hormone, or lack of anti-Mullerian hormone, leading to persistence of the female internal sex organs in a male. Clinically, this condition is associated with cryptochoridism. Controversy persists regarding the appropriate treatment of PMDS, since resection of the remnant structures is associated with potential morbidity, but retention risks development of occasional malignancies. We review the literature and discuss various aspects of pathophysiology, diagnosis, and management of PMDS.

  20. Common bile duct pathologies at nawabshah

    To determine the causes, presentation, management and outcome of Common Bile Duct (CBD) pathologies. All patients who presented with CBD pathologies. Data of all the patients with CBD pathologies was collected and entered on a proforma, including their complaints, positive examination findings, investigations, diagnosis, procedure performed and its outcome. During the study period 45 patients presented with CBD pathology. Amongst them 14 were males and the rest females (31), with a mean age of 36.7 years. Around 67% patients had choledocholithiasis as the commonest cause. Exploration of the CBD with T-tube insertion was the commonest procedure, performed in 69% patients. About 4% patients had retained stones and 20% developed wound infection. Mean hospital stay was 13 days. Most common pathology involving the CBD was secondary stones; 95% patients had associated gall stones also. (author)

  1. Shallow Water Acoustic Laboratory

    Federal Laboratory Consortium — FUNCTION: Supports experimental research where high-frequency acoustic scattering and surface vibration measurements of fluid-loaded and non-fluid-loaded structures...

  2. Handbook of Engineering Acoustics

    Möser, Michael

    2013-01-01

    This book examines the physical background of engineering acoustics, focusing on empirically obtained engineering experience as well as on measurement techniques and engineering methods for prognostics. Its goal is not only to describe the state of art of engineering acoustics but also to give practical help to engineers in order to solve acoustic problems. It deals with the origin, the transmission and the methods of the abating different kinds of air-borne and structure-borne sounds caused by various mechanisms – from traffic to machinery and flow-induced sound. In addition the modern aspects of room and building acoustics, as well as psychoacoustics and active noise control, are covered.

  3. Acoustic dispersive prism

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  4. Localized Acoustic Surface Modes

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  5. Low-dispersion finite difference methods for acoustic waves in a pipe

    Davis, Sanford

    1991-01-01

    A new algorithm for computing one-dimensional acoustic waves in a pipe is demonstrated by solving the acoustic equations as an initial-boundary-value problem. Conventional dissipation-free second-order finite difference methods suffer severe phase distortion for grids with less that about ten mesh points per wavelength. Using the signal generation by a piston in a duct as an example, transient acoustic computations are presented using a new compact three-point algorithm which allows about 60 percent fewer mesh points per wavelength. Both pulse and harmonic excitation are considered. Coupling of the acoustic signal with the pipe resonant modes is shown to generate a complex transient wave with rich harmonic content.

  6. Modelling of wind tunnel wall effects on the radiation characteristics of acoustic sources

    Eversman, W.; Baumeister, K. J.

    1984-01-01

    It is pointed out that the relatively high fuel economy available from propeller-driven aircraft has renewed interest in high speed, highly loaded multiple blade turboprop propulsion systems. Undesirable features related to community noise and the high intensity cabin noise have stimulated new research on the acoustic characteristics of turboprops. The present investigation has the objective to develop a mathematical model of the essential features of the radiation of acoustic disturbances from propellers in a duct and in free space in order to quantify the success with which duct testing can be expected to approximate free field conditions. In connection with the importance of source directionality, a detailed model is considered which consists of a finite element representation of the Gutin propeller theory valid in both the near and far field.

  7. What Is an Acoustic Neuroma

    ... org Connect with us! What is an Acoustic Neuroma? Each heading slides to reveal information. Important Points ... Neuroma Important Points To Know About an Acoustic Neuroma An acoustic neuroma, also called a vestibular schwannoma, ...

  8. Time-Dependent Parabolic Finite Difference Formulation for Harmonic Sound Propagation in a Two-Dimensional Duct with Flow

    Kreider, Kevin L.; Baumeister, Kenneth J.

    1996-01-01

    An explicit finite difference real time iteration scheme is developed to study harmonic sound propagation in aircraft engine nacelles. To reduce storage requirements for future large 3D problems, the time dependent potential form of the acoustic wave equation is used. To insure that the finite difference scheme is both explicit and stable for a harmonic monochromatic sound field, a parabolic (in time) approximation is introduced to reduce the order of the governing equation. The analysis begins with a harmonic sound source radiating into a quiescent duct. This fully explicit iteration method then calculates stepwise in time to obtain the 'steady state' harmonic solutions of the acoustic field. For stability, applications of conventional impedance boundary conditions requires coupling to explicit hyperbolic difference equations at the boundary. The introduction of the time parameter eliminates the large matrix storage requirements normally associated with frequency domain solutions, and time marching attains the steady-state quickly enough to make the method favorable when compared to frequency domain methods. For validation, this transient-frequency domain method is applied to sound propagation in a 2D hard wall duct with plug flow.

  9. Modeling low elevation GPS signal propagation in maritime atmospheric ducts

    Zhang, Jinpeng; Wu, Zhensen; Wang, Bo; Wang, Hongguang; Zhu, Qinglin

    2012-05-01

    Using the parabolic wave equation (PWE) method, we model low elevation GPS L1 signal propagation in maritime atmospheric ducts. To consider sea surface impedance, roughness, and the effects of earth's curvature, we propose a new initial field model for the GPS PWE split-step solution. On the basis of the comparison between the proposed model and the conventional initial field model for a smooth, perfectly conducting sea surface on a planar earth, we conclude that both the amplitude and phase of the initial field are influenced by surface impedance and roughness, and that the interference behavior between direct and reflected GPS rays is affected by earth's curvature. The performance of the proposed model is illustrated with examples of low elevation GPS L1 signal propagation in three types of ducts: an evaporation duct, a surface-based duct, and an elevated duct. The GPS PWE is numerically implemented using the split-step discrete mixed Fourier transform algorithm to enforce impedance-type boundary conditions at the rough sea surface. Because the GPS signal is right hand circularly polarized, we calculate its power strength by combining the propagation predictions of the horizontally and the vertically polarized components. The effects of the maritime atmospheric ducts on low elevation GPS signal propagation are demonstrated according to the presented examples, and the potential applications of the GPS signals affected by ducts are discussed.

  10. Mechanical properties of the porcine bile duct wall

    Andersen Helle

    2004-07-01

    Full Text Available Abstract Background and Aim The function of the common bile duct is to transport bile from the liver and the gall bladder to the duodenum. Since the bile duct is a distensible tube consisting mainly of connective tissue, it is important to obtain data on the passive mechanical wall properties. The aims of this study were to study morphometric and biomechanical wall properties during distension of the bile duct. Methods Ten normal porcine common bile ducts were examined in vitro. A computer-controlled volume ramp infusion system with concomitant pressure recordings was constructed. A video camera provided simultaneous measurement of outer dimensions of the common bile duct. Wall stresses and strains were computed. Results The common bile duct length increased by 25% from 24.4 ± 1.8 mm at zero pressure to 30.5 ± 2.0 mm at 5 kPa (p (βε - 1. The circumferential stress-strain curve was shifted to the left when compared to the longitudinal stress-strain curve, i.e. the linear constants (α values were different (p 0.5. Conclusion The porcine bile duct exhibited nonlinear anisotropic mechanical properties.