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Sample records for advanced ducted propulsor

  1. Internal Acoustics Measurements of a Full Scale Advanced Ducted Propulsor Demonstrator

    NASA Technical Reports Server (NTRS)

    Santa Maria, O. L.; Soderman, P. T.; Horne, W. C.; Jones, M. G.; Bock, L. A.

    1995-01-01

    Acoustics measurements of a Pratt & Whitney full-scale ADP (Advanced Ducted Propulsor), an ultrahigh by-pass ratio engine, were conducted in the NASA Ames 40- by 80-Foot Wind Tunnel. This paper presents data from measurements taken from sensors on a fan exit guide vane in the ADP. Data from two sensors, one at mid-span and the other at the tip of the fan exit guide vane, are presented. At the blade passage frequency (BPF), the levels observed at the various engine and wind speeds were higher at the mid-span sensor than the tip sensor. The coherence between these internal sensors and external microphones were calculated and plotted as a function of angle (angles ranged from 5 degrees to 160 degrees) relative to the ADP longitudinal axis. At the highest engine and wind speeds, the coherence between the tip sensor and the external microphones was observed to decrease at higher multiples of the BPF. These results suggest that the rotor-stator interaction tones are stronger in the mid-span region than at the tip.

  2. Some Acoustic Results from the Pratt and Whitney Advanced Ducted Propulsor: Fan 1

    NASA Technical Reports Server (NTRS)

    Dittmar, James H.; Elliott, David M.; Bock, Lawrence A.

    1999-01-01

    Noise measurements were obtained for the Advanced Ducted Propulsor (ADP) - Fan 1, with and without nacelle acoustic treatment. The fan was tested with no acoustic treatment (hard wall) and with acoustic treatment installed in three configurations in the nacelle (mid, mid plus aft, fully treated). The hard wall results showed that the radiated noise from the fan came primarily from the aft end of the nacelle. At takeoff and higher speeds, the noise measured at the inlet angles was also found to be dominated by noise from the aft end. Significant amounts of attenuation were observed with acoustic treatment installed and comparison with predictions showed the treatment gave more attenuation than predicted. Effective Perceived Noise Levels were determined for a large hypothetical 4 engine airplane. These levels showed that the installed acoustic treatment provided as much as 5 EPNdB of noise reduction. A traverse with a probe having three microphones, one above the other, showed azimuthal variations in the noise that need to be further investigated.

  3. Computational Aerodynamic Simulations of an 840 ft/sec Tip Speed Advanced Ducted Propulsor Fan System Model for Acoustic Methods Assessment and Development

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2014-01-01

    Computational Aerodynamic simulations of an 840 ft/sec tip speed, Advanced Ducted Propulsor fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, lownoise research fan/nacelle model that has undergone extensive experimental testing in the 9- by 15- foot Low Speed Wind Tunnel at the NASA Glenn Research Center, resulting in quality, detailed aerodynamic and acoustic measurement data. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating conditions simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, excluding a long core duct section downstream of the core inlet guide vane. As a result, only fan rotational speed and system bypass ratio, set by specifying static pressure downstream of the core inlet guide vane row, were adjusted in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. The computed blade row flow fields for all five fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the computed flow fields reveals no excessive boundary layer separations or related secondary-flow problems. A few spanwise comparisons between

  4. Model ducted propulsor noise characteristics at takeoff conditions

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Bock, Lawrence A.; Heidelberg, Laurence J.; Hall, David G.

    1994-01-01

    A model Advanced Ducted Propulsor (ADP) was tested in the NASA Lewis Low-Speed Anechoic Wind Tunnel at a simulated takeoff velocity of Mach 0.2. The model was designed and manufactured by Pratt & Whitney. The 16-blade rotor ADP was tested with 22- and 40-vane stators to achieve cut-on and cut-off criterion with respect to propagation of the fundamental rotor-stator interaction tone. Additional test parameters included three inlet lengths, three nozzle sizes, two spinner configurations, and two rotor rub strip configurations. The model was tested over a range of rotor blade setting angles and inlet angles of attack. Acoustic data were taken with a sideline translating microphone probe and with a unique inlet microphone probe that identified inlet rotating acoustic modes. The beneficial acoustic effects of cut-off were clearly demonstrated. A 10-dB fundamental tone reduction was associated with the long inlet and 40-vane stator. The fundamental tone level was essentially unaffected by inlet angle of attack at rotor speeds of above 96% design.

  5. Investigation of Pneumatic Inlet and Diffuser Blowing on a Ducted Fan Propulsor in Static Thrust Operation

    NASA Technical Reports Server (NTRS)

    Kondor, Shayne; Englar, Robert J.; Lee, Warren J.

    2003-01-01

    Tilting ducted fans present a solution for the lifting and forward flight propulsion requirements of VTOL aircraft. However, the geometry of the duct enshrouding the propeller has great a effect on the efficiency of the fan in various flight modes. Shroud geometry controls the velocity and pressure at the face of the fan, while maintaining a finite loading out at the tips of the fan blades. A duct tailored for most efficient generation of static lifting thrust will generally suffer from performance deficiencies in forward flight. The converse is true as well, leaving the designer with a difficult trade affecting the overall performance and sizing of the aircraft. Ideally, the shroud of a vertical lifting fan features a generous bell mouth inlet promoting acceleration of flow into the face of the fan, and terminating in a converging nozzle at the exit. Flow entering the inlet is accelerated into the fan by the circulation about the shroud, resulting in an overall increase in thrust compared to an open propeller operating under the same conditions . The accelerating shroud design is often employed in lifting ducted fans to benefit from the thrust augmentation; however, such shroud designs produce significant drag penalties in axial flight, thus are unsuitable for efficient forward flight applications. Decelerating, or diffusing, duct designs are employed for higher speed forward flight configurations. The lower circulation on the shroud tends to decelerate the flow into the face of the fan, which is detrimental to static thrust development; however, net thrust is developed on the shroud while the benefits of finite blade loading are retained. With judicious shroud design for intended flight speeds, a net increase in efficiency can be obtained over an open propeller. In this experiment, conducted under contract to NASA LaRC (contract NAG-1-02093) circulation control is being applied to a mildly diffusing shroud design, intended for improved forward flight performance

  6. Advanced Duct Sealing Testing

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.

    2003-08-01

    Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have typically shown that these seals tend to fail over extended periods of time. The Lawrence Berkeley National Laboratory has been testing sealant durability for several years. Typical duct tape (i.e. fabric backed tapes with natural rubber adhesives) was found to fail more rapidly than all other duct sealants. This report summarizes the results of duct sealant durability testing of five UL 181B-FX listed duct tapes (three cloth tapes, a foil tape and an Oriented Polypropylene (OPP) tape). One of the cloth tapes was specifically developed in collaboration with a tape manufacturer to perform better in our durability testing. The first test involved the aging of common ''core-to-collar joints'' of flexible duct to sheet metal collars, and sheet metal ''collar-to-plenum joints'' pressurized with 200 F (93 C) air. The second test consisted of baking duct tape specimens in a constant 212 F (100 C) oven following the UL 181B-FX ''Temperature Test'' requirements. Additional tests were also performed on only two tapes using sheet metal collar-to-plenum joints. Since an unsealed flexible duct joint can have a variable leakage depending on the positioning of the flexible duct core, the durability of the flexible duct joints could not be based on the 10% of unsealed leakage criteria. Nevertheless, the leakage of the sealed specimens prior to testing could be considered as a basis for a failure criteria. Visual inspection was also documented throughout the tests. The flexible duct core-to-collar joints were inspected monthly, while the sheet metal collar-to-plenum joints were inspected

  7. Tradespace Exploration of Distributed Propulsors for Advanced On-Demand Mobility Concepts

    NASA Technical Reports Server (NTRS)

    Borer, Nicholas K.; Moore, Mark D.; Turnbull, Andrew R.

    2014-01-01

    Combustion-based sources of shaft power tend to significantly penalize distributed propulsion concepts, but electric motors represent an opportunity to advance the use of integrated distributed propulsion on an aircraft. This enables use of propellers in nontraditional, non-thrust-centric applications, including wing lift augmentation, through propeller slipstream acceleration from distributed leading edge propellers, as well as wingtip cruise propulsors. Developing propellers for these applications challenges long-held constraints within propeller design, such as the notion of optimizing for maximum propulsive efficiency, or the use of constant-speed propellers for high-performance aircraft. This paper explores the design space of fixed-pitch propellers for use as (1) lift augmentation when distributed about a wing's leading edge, and (2) as fixed-pitch cruise propellers with significant thrust at reduced tip speeds for takeoff. A methodology is developed for evaluating the high-level trades for these types of propellers and is applied to the exploration of a NASA Distributed Electric Propulsion concept. The results show that the leading edge propellers have very high solidity and pitch well outside of the empirical database, and that the cruise propellers can be operated over a wide RPM range to ensure that thrust can still be produced at takeoff without the need for a pitch change mechanism. To minimize noise exposure to observers on the ground, both the leading edge and cruise propellers are designed for low tip-speed operation during takeoff, climb, and approach.

  8. Advanced Turbofan Duct Liner Concepts

    NASA Technical Reports Server (NTRS)

    Bielak, Gerald W.; Premo, John W.; Hersh, Alan S.

    1999-01-01

    The Advanced Subsonic Technology Noise Reduction Program goal is to reduce aircraft noise by 10 EPNdB by the year 2000 relative, to 1992 technology. The improvement goal for nacelle attenuation is 25% relative to 1992 technology by 1997 and 50% by 2000. The Advanced Turbofan Duct Liner Concepts Task work by Boeing presented in this document was in support of these goals. The basis for the technical approach was a Boeing study conducted in 1993-94 under NASA/FAA contract NAS1-19349, Task 6, investigating broadband acoustic liner concepts. As a result of this work, it was recommended that linear double layer, linear and perforate triple layer, parallel element, and bulk absorber liners be further investigated to improve nacelle attenuations. NASA LaRC also suggested that "adaptive" liner concepts that would allow "in-situ" acoustic impedance control also be considered. As a result, bias flow and high-temperature liner concepts were also added to the investigation. The major conclusion from the above studies is that improvements in nacelle liner average acoustic impedance characteristics alone will not result in 25% increased nacelle noise reduction relative to 1992 technology. Nacelle design advancements currently being developed by Boeing are expected to add 20-40% more acoustic lining to hardwall regions in current inlets, which is predicted to result in and additional 40-80% attenuation improvement. Similar advancements are expected to allow 10-30% more acoustic lining in current fan ducts with 10-30% more attenuation expected. In addition, Boeing is currently developing a scarf inlet concept which is expected to give an additional 40-80% attenuation improvement for equivalent lining areas.

  9. Technology readiness for advanced ducted engines

    SciTech Connect

    Eckardt, D.; Brines, G.L.

    1989-01-01

    The Advanced Ducted Engines (ADEs) currently undergoing development for next-generation passenger aircraft typically possess bypass ratios of the order of 12-25 and specific fuel consumption figures 12-17 percent lower than current advanced turbofans. An extensive technology-readiness program has been mounted on behalf of ADE design definition over the last two years, encompassing among its concerns aircraft/engine-installation interference, low pressure-ratio fan aerodynamics, fan/nacelle interactions (including windmilling and thrust-reversal), acoustic characteristics, transonic-drive turbines, and slender nacelle aerodynamic and mechanical design. Both turbine-driven and geared ADE fans, which may be of single-rotating or contrarotating type, are discussed. 5 refs.

  10. Large Eddy Simulation of Crashback in Marine Propulsors

    NASA Astrophysics Data System (ADS)

    Jang, Hyunchul

    Crashback is an operating condition to quickly stop a propelled vehicle, where the propeller is rotated in the reverse direction to yield negative thrust. The crashback condition is dominated by the interaction of the free stream flow with the strong reverse flow. This interaction forms a highly unsteady vortex ring, which is a very prominent feature of crashback. Crashback causes highly unsteady loads and flow separation on the blade surface. The unsteady loads can cause propulsor blade damage, and also affect vehicle maneuverability. Crashback is therefore well known as one of the most challenging propeller states to analyze. This dissertation uses Large-Eddy Simulation (LES) to predict the highly unsteady flow field in crashback. A non-dissipative and robust finite volume method developed by Mahesh et al. (2004) for unstructured grids is applied to flow around marine propulsors. The LES equations are written in a rotating frame of reference. The objectives of this dissertation are: (1) to understand the flow physics of crashback in marine propulsors with and without a duct, (2) to develop a finite volume method for highly skewed meshes which usually occur in complex propulsor geometries, and (3) to develop a sliding interface method for simulations of rotor-stator propulsor on parallel platforms. LES is performed for an open propulsor in crashback and validated against experiments performed by Jessup et al. (2004). The LES results show good agreement with experiments. Effective pressures for thrust and side-force are introduced to more clearly understand the physical sources of thrust and side-force. Both thrust and side-force are seen to be mainly generated from the leading edge of the suction side of the propeller. This implies that thrust and side-force have the same source---the highly unsteady leading edge separation. Conditional averaging is performed to obtain quantitative information about the complex flow physics of high- or low-amplitude events. The

  11. Efficient, Low Pressure Ratio Propulsor for Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    Gallagher, Edward J. (Inventor); Monzon, Byron R. (Inventor)

    2015-01-01

    A gas turbine engine includes a spool, a turbine coupled to drive the spool, and a propulsor that is coupled to be driven by the turbine through the spool. A gear assembly is coupled between the propulsor and the spool such that rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extends from the hub. The row includes no more than 20 of the propulsor blades.

  12. Analysis of an advanced ducted propeller subsonic inlet

    NASA Technical Reports Server (NTRS)

    Iek, Chanthy; Boldman, Donald R.; Ibrahim, Mounir

    1992-01-01

    It is shown that a time marching Navier-Stokes code called PARC can be utilized to provide a reasonable prediction of the flow field within an inlet for an advanced ducted propeller. The code validation was implemented for a nonseparated flow condition associated with the inlet functioning at angles-of-attack of zero and 25 deg. Comparison of the computational results with the test data shows that the PARC code with the propeller face fixed flow properties boundary conditions (BC) provided a better prediction of the inlet surface static pressures than the prediction when the mass flow BC was employed.

  13. Flexible propulsors in ground effect.

    PubMed

    Quinn, Daniel B; Lauder, George V; Smits, Alexander J

    2014-09-01

    We present experimental evidence for the hydrodynamic benefits of swimming 'in ground effect', that is, near a solid boundary. This situation is common to fish that swim near the substrate, especially those that are dorsoventrally compressed, such as batoids and flatfishes. To investigate flexible propulsors in ground effect, we conduct force measurements and particle image velocimetry on flexible rectangular panels actuated at their leading edge near the wall of a water channel. For a given actuation mode, the panels swim faster near the channel wall while maintaining the same propulsive economy. In conditions producing net thrust, panels produce more thrust near the ground. When operating in resonance, swimming near the ground can also increase propulsive efficiency. Finally, the ground can act to suppress three-dimensional modes, thereby increasing thrust and propulsive efficiency. The planform considered here is non-biological, but the hydrodynamic benefits are likely to apply to more complex geometries, especially those where broad flexible propulsors are involved such as fish bodies and fins. Such fish could produce more thrust by swimming near the ground, and in some cases do so more efficiently. PMID:24667542

  14. Flexible propulsors in ground effect.

    PubMed

    Quinn, Daniel B; Lauder, George V; Smits, Alexander J

    2014-09-01

    We present experimental evidence for the hydrodynamic benefits of swimming 'in ground effect', that is, near a solid boundary. This situation is common to fish that swim near the substrate, especially those that are dorsoventrally compressed, such as batoids and flatfishes. To investigate flexible propulsors in ground effect, we conduct force measurements and particle image velocimetry on flexible rectangular panels actuated at their leading edge near the wall of a water channel. For a given actuation mode, the panels swim faster near the channel wall while maintaining the same propulsive economy. In conditions producing net thrust, panels produce more thrust near the ground. When operating in resonance, swimming near the ground can also increase propulsive efficiency. Finally, the ground can act to suppress three-dimensional modes, thereby increasing thrust and propulsive efficiency. The planform considered here is non-biological, but the hydrodynamic benefits are likely to apply to more complex geometries, especially those where broad flexible propulsors are involved such as fish bodies and fins. Such fish could produce more thrust by swimming near the ground, and in some cases do so more efficiently.

  15. Multiple advanced surgical techniques to treat acquired seminal duct obstruction

    PubMed Central

    Jiang, Hong-Tao; Yuan, Qian; Liu, Yu; Liu, Zeng-Qin; Zhou, Zhen-Yu; Xiao, Ke-Feng; Yang, Jiang-Gen

    2014-01-01

    The aim of this study was to evaluate the outcomes of multiple advanced surgical treatments (i.e. microsurgery, laparoscopic surgery and endoscopic surgery) for acquired obstructive azoospermia. We analyzed the surgical outcomes of 51 patients with suspected acquired obstructive azoospermia consecutively who enrolled at our center between January 2009 and May 2013. Modified vasoepididymostomy, laparoscopically assisted vasovasostomy and transurethral incision of the ejaculatory duct with holmium laser were chosen and performed based on the different obstruction sites. The mean postoperative follow-up time was 22 months (range: 9 months to 52 months). Semen analyses were initiated at four postoperative weeks, followed by trimonthly (months 3, 6, 9 and 12) semen analyses, until no sperm was found at 12 months or until pregnancy was achieved. Patency was defined as >10,000 sperm ml−1 of semen. The obstruction sites, postoperative patency and natural pregnancy rate were recorded. Of 51 patients, 47 underwent bilateral or unilateral surgical reconstruction; the other four patients were unable to be treated with surgical reconstruction because of pelvic vas or intratesticular tubules obstruction. The reconstruction rate was 92.2% (47/51), and the patency rate and natural pregnancy rate were 89.4% (42/47) and 38.1% (16/42), respectively. No severe complications were observed. Using multiple advanced surgical techniques, more extensive range of seminal duct obstruction was accessible and correctable; thus, a favorable patency and pregnancy rate can be achieved. PMID:25337841

  16. Vortex interaction between two tandem flexible propulsors

    NASA Astrophysics Data System (ADS)

    Park, Sung Goon; Sung, Hyung Jin; Flow Control Laboratory Team

    2015-11-01

    Schooling behaviors of flying and swimming animals are widespread phenomena in nature. Inspired by schooling behaviors of swimming jellyfish, self-propelling flexible bodies with a paddling-based locomotion were modeled in a tandem configuration. The interactions between surrounding fluids and propulsors were considered by using the immersed boundary method. The hydrodynamic patterns generated by the interactions between tandem flexible propulsors were analyzed in the presen study. As a result of the flow-mediated interactions between them, stable configurations were formed spontaneously in which the gap distance between propulsors increased and decreased during the contraction and relaxation phases of the upstream propulsor. The stable configuration was not affected by the initial gap distance but influenced by the phase difference in the flapping frequency between them. Both tandem propulsors benefited from the tandem configuration in terms of the locomotion as compared with an isolated propulsor. This study was supported by the Creative Research Initiatives (No. 2015-001828) program of the National Research Foundation of Korea (MSIP).

  17. CPI-613 in Treating Patients With Advanced or Metastatic Bile Duct Cancer That Cannot Be Removed By Surgery

    ClinicalTrials.gov

    2016-07-26

    Adult Primary Cholangiocellular Carcinoma; Advanced Adult Primary Liver Cancer; Cholangiocarcinoma of the Extrahepatic Bile Duct; Cholangiocarcinoma of the Gallbladder; Localized Unresectable Adult Primary Liver Cancer; Metastatic Extrahepatic Bile Duct Cancer; Recurrent Adult Primary Liver Cancer; Recurrent Extrahepatic Bile Duct Cancer; Unresectable Extrahepatic Bile Duct Cancer

  18. Analysis of an advanced ducted propeller subsonic inlet

    NASA Technical Reports Server (NTRS)

    Iek, Chanthy; Boldman, Donald R.; Ibrahim, Mounir

    1992-01-01

    A time marching Navier-Stokes code called PARC (PARC2D for 2-D/axisymmetric and PARC3D for 3-D flow simulations) was validated for an advanced ducted propeller (ADP) subsonic inlet. The code validation for an advanced ducted propeller (ADP) subsonic inlet. The code validation was implemented for a non-separated flow condition associated with the inlet operating at angles-of-attack of 0 and 25 degrees. The inlet test data were obtained in the 9 x 15 ft Low Speed Wind Tunnel at NASA Lewis Research Center as part of a cooperative study with Pratt and Whitney. The experimental study focused on the ADP inlet performance for take-off and approach conditions. The inlet was tested at a free stream Mach number of 0.2, at angles-of-attack between O and 35 degrees, and at a maximum propeller speed of 12,000 RPM which induced a corrected air flow rate of about 46 lb/sec based on standard day conditions. The computational grid and flow boundary conditions (BC) were based on the actual inlet geometry and the funnel flow conditions. At the propeller face, two types of BC's were applied: a mass flow BC and a fixed flow properties BC. The fixed flow properties BC was based on a combination of data obtained from the experiment and calculations using a potential flow code. Comparison of the computational results with the test data indicates that the PARC code with the propeller face fixed flow properties BC provided a better prediction of the inlet surface static pressures than the predictions when the mass flow BC was used. For an angle-of-attack of 0 degrees, the PARC2D code with the propeller face mass flow BC provided a good prediction of inlet static pressures except in the region of high pressure gradient. With the propeller face fixed flow properties BC, the PARC2D code provided a good prediction of the inlet static pressures. For an angle-of-attack of 25 degrees with the mass flow BC, the PARC3D code predicted statis pressures which deviated significantly from the test data

  19. Advanced Strategy Guideline: Air Distribution Basics and Duct Design

    SciTech Connect

    Burdick, A.

    2011-12-01

    This report discusses considerations for designing an air distribution system for an energy efficient house that requires less air volume to condition the space. Considering the HVAC system early in the design process will allow adequate space for equipment and ductwork and can result in cost savings. Principles discussed that will maximize occupant comfort include delivery of the proper amount of conditioned air for appropriate temperature mixing and uniformity without drafts, minimization of system noise, the impacts of pressure loss, efficient return air duct design, and supply air outlet placement, as well as duct layout, materials, and sizing.

  20. Bortezomib in Treating Patients With Unresectable Locally Advanced or Metastatic Adenocarcinoma of the Bile Duct or Gallbladder

    ClinicalTrials.gov

    2013-01-11

    Adenocarcinoma of the Extrahepatic Bile Duct; Adenocarcinoma of the Gallbladder; Advanced Adult Primary Liver Cancer; Gastrointestinal Cancer; Localized Unresectable Adult Primary Liver Cancer; Recurrent Adult Primary Liver Cancer; Recurrent Extrahepatic Bile Duct Cancer; Recurrent Gallbladder Cancer; Unresectable Extrahepatic Bile Duct Cancer; Unresectable Gallbladder Cancer

  1. An estimate of the noise shielding on the fuselage resulting from installing a short duct around an advanced propeller

    NASA Technical Reports Server (NTRS)

    Dittmar, James H.

    1988-01-01

    A simple barrier shielding model was used to estimate the amount of noise shielding on the fuselage that could result from installing a short duct around a wing-mounted advanced propeller. With the propeller located one-third of the duct length from the inlet, estimates for the maximum blade passing tone attenuation varied from 7 dB for a duct 0.25 propeller diameter long to 16.75 dB for a duct 1 diameter long. Attenuations for the higher harmonics would be even larger because of their shorter wavelengths relative to the duct length. These estimates show that the fuselage noise reduction potential of a ducted compared with an unducted propeller is significant. Even more reduction might occur if acoustic attenuation material were installed in the duct.

  2. Cladding and Duct Materials for Advanced Nuclear Recycle Reactors

    SciTech Connect

    Allen, Todd R.; Busby, Jeremy T; Klueh, Ronald L; Maloy, S; Toloczko, M

    2008-01-01

    The expanded use of nuclear energy without risk of nuclear weapons proliferation and with safe nuclear waste disposal is a primary goal of the Global Nuclear Energy Partnership (GNEP). To achieve that goal the GNEP is exploring advanced technologies for recycling spent nuclear fuel that do not separate pure plutonium, and advanced reactors that consume transuranic elements from recycled spent fuel. The GNEP s objectives will place high demands on reactor clad and structural materials. This article discusses the materials requirements of the GNEP s advanced nuclear recycle reactors program.

  3. Cladding and duct materials for advanced nuclear recycle reactors

    NASA Astrophysics Data System (ADS)

    Allen, T. R.; Busby, J. T.; Klueh, R. L.; Maloy, S. A.; Toloczko, M. B.

    2008-01-01

    The expanded use of nuclear energy without risk of nuclear weapons proliferation and with safe nuclear waste disposal is a primary goal of the Global Nuclear Energy Partnership (GNEP). To achieve that goal the GNEP is exploring advanced technologies for recycling spent nuclear fuel that do not separate pure plutonium, and advanced reactors that consume transuranic elements from recycled spent fuel. The GNEP’s objectives will place high demands on reactor clad and structural materials. This article discusses the materials requirements of the GNEP’s advanced nuclear recycle reactors program.

  4. A computational study of advanced exhaust system transition ducts with experimental validation

    NASA Technical Reports Server (NTRS)

    Wu, C.; Farokhi, S.; Taghavi, R.

    1992-01-01

    The current study is an application of CFD to a 'real' design and analysis environment. A subsonic, three-dimensional parabolized Navier-Stokes (PNS) code is used to construct stall margin design charts for optimum-length advanced exhaust systems' circular-to-rectangular transition ducts. Computer code validation has been conducted to examine the capability of wall static pressure predictions. The comparison of measured and computed wall static pressures indicates a reasonable accuracy of the PNS computer code results. Computations have also been conducted on 15 transition ducts, three area ratios, and five aspect ratios. The three area ratios investigated are constant area ratio of unity, moderate contracting area ratio of 0.8, and highly contracting area ratio of 0.5. The degree of mean flow acceleration is identified as a dominant parameter in establishing the minimum duct length requirement. The effect of increasing aspect ratio in the minimum length transition duct is to increase the length requirement, as well as to increase the mass-averaged total pressure losses. The design guidelines constructed from this investigation may aid in the design and manufacture of advanced exhaust systems for modern fighter aircraft.

  5. Flapping dynamics of a flexible propulsor near ground

    NASA Astrophysics Data System (ADS)

    Ryu, Jaeha; Park, Sung Goon; Kim, Boyoung; Sung, Hyung Jin

    2016-06-01

    The flapping motion of a flexible propulsor near the ground was simulated using the immersed boundary method. The hydrodynamic benefits of the propulsor near the ground were explored by varying the heaving frequency (St) of the leading edge of the flexible propulsor. Propulsion near the ground had some advantages in generating thrust and propelling faster than propulsion away from the ground. The mode analysis and flapping amplitude along the Lagrangian coordinate were examined to analyze the kinematics as a function of the ground proximity (d) and St. The trailing edge amplitude (a_tail ) and the net thrust (overline{{F}}_x ) were influenced by St of the flexible propulsor. The vortical structures in the wake were analyzed for different flapping conditions.

  6. Radial inflow gas turbine engine with advanced transition duct

    SciTech Connect

    Wiebe, David J

    2015-03-17

    A gas turbine engine (10), including: a turbine having radial inflow impellor blades (38); and an array of advanced transition combustor assemblies arranged circumferentially about the radial inflow impellor blades (38) and having inner surfaces (34) that are adjacent to combustion gases (40). The inner surfaces (34) of the array are configured to accelerate and orient, for delivery directly onto the radial inflow impellor blades (38), a plurality of discrete flows of the combustion gases (40). The array inner surfaces (34) define respective combustion gas flow axes (20). Each combustion gas flow axis (20) is straight from a point of ignition until no longer bound by the array inner surfaces (34), and each combustion gas flow axis (20) intersects a unique location on a circumference defined by a sweep of the radial inflow impellor blades (38).

  7. Cholangiocarcinoma and malignant bile duct obstruction: A review of last decades advances in therapeutic endoscopy

    PubMed Central

    Bertani, Helga; Frazzoni, Marzio; Mangiafico, Santi; Caruso, Angelo; Manno, Mauro; Mirante, Vincenzo Giorgio; Pigò, Flavia; Barbera, Carmelo; Manta, Raffaele; Conigliaro, Rita

    2015-01-01

    In the last decades many advances have been achieved in endoscopy, in the diagnosis and therapy of cholangiocarcinoma, however blood test, magnetic resonance imaging, computed tomography scan may fail to detect neoplastic disease at early stage, thus the diagnosis of cholangiocarcinoma is achieved usually at unresectable stage. In the last decades the role of endoscopy has moved from a diagnostic role to an invaluable therapeutic tool for patients affected by malignant bile duct obstruction. One of the major issues for cholangiocarcinoma is bile ducts occlusion, leading to jaundice, cholangitis and hepatic failure. Currently, endoscopy has a key role in the work up of cholangiocarcinoma, both in patients amenable to surgical intervention as well as in those unfit for surgery or not amenable to immediate surgical curative resection owing to locally advanced or advanced disease, with palliative intention. Endoscopy allows successful biliary drainage and stenting in more than 90% of patients with malignant bile duct obstruction, and allows rapid reduction of jaundice decreasing the risk of biliary sepsis. When biliary drainage and stenting cannot be achieved with endoscopy alone, endoscopic ultrasound-guided biliary drainage represents an effective alternative method affording successful biliary drainage in more than 80% of cases. The purpose of this review is to focus on the currently available endoscopic management options in patients with cholangiocarcinoma. PMID:26078827

  8. Selumetinib and Akt Inhibitor MK-2206 in Treating Patients With Refractory or Advanced Gallbladder or Bile Duct Cancer That Cannot Be Removed By Surgery

    ClinicalTrials.gov

    2014-09-08

    Adenocarcinoma of the Gallbladder; Adenocarcinoma With Squamous Metaplasia of the Gallbladder; Adult Primary Cholangiocellular Carcinoma; Advanced Adult Primary Liver Cancer; Cholangiocarcinoma of the Extrahepatic Bile Duct; Localized Unresectable Adult Primary Liver Cancer; Metastatic Extrahepatic Bile Duct Cancer; Recurrent Adult Primary Liver Cancer; Recurrent Extrahepatic Bile Duct Cancer; Stage II Gallbladder Cancer; Stage IIIA Gallbladder Cancer; Stage IIIB Gallbladder Cancer; Stage IVA Gallbladder Cancer; Stage IVB Gallbladder Cancer; Unresectable Extrahepatic Bile Duct Cancer

  9. Advanced in-duct sorbent injection for SO{sub 2} control. Final technical report

    SciTech Connect

    Stouffer, M.R.; Withium, J.A.; Rosenhoover, W.A.; Maskew, J.T.

    1994-12-01

    The objective of this research project was to develop a second generation duct sorbent injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Research and development work was focused on the Advanced Coolside process, which showed the potential for exceeding the original performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. Process development was conducted in a 1000 acfm pilot plant. The pilot plant testing showed that the Advanced Coolside process can achieve 90% SO{sub 2} removal at sorbent utilizations up to 75%. The testing also showed that the process has the potential to achieve very high removal efficiency (90 to >99%). By conducting conceptual process design and economic evaluations periodically during the project, development work was focused on process design improvements which substantially lowered process capital and operating costs, A final process economic study projects capital costs less than one half of those for limestone forced oxidation wet FGD. Projected total SO{sub 2} control cost is about 25% lower than wet FGD for a 260 MWe plant burning a 2.5% sulfur coal. A waste management study showed the acceptability of landfill disposal; it also identified a potential avenue for by-product utilization which should be further investigated. Based on the pilot plant performance and on the above economic projections, future work to scale up the Advanced Coolside process is recommended.

  10. Resultados do desenvolvimento de um propulsor à plasma no Brasil

    NASA Astrophysics Data System (ADS)

    Ferreira, I. S.; Ferreira, J. L.

    2003-08-01

    Uma das partes mais importantes de um satélite é o controle de atitude do mesmo. E se tratando de um satélite científico, a atenção para este sistema deve ser redobrada. Uma possibilidade atraente para executar esta tarefa é a propulsão elétrica. Aqui, mostraremos resultados obtidos pelo propulsor à plasma PHALL-01, desenvolvido na Universidade de Brasília entre 2000 e 2003. Este é derivado do propulsor russo SPT-100 (Stationary Plasma Thruster), mas com o emprego inovador de um arranjo de imãs permanentes como fonte do campo magnético, este último o agente da aceleração do plasma. Esta alteração foi motivada pelo objetivo de que o mesmo operasse com o mínimo de potência elétrica. A partir da formulação teórica do mecanismo de aceleração, tendo como base as equações da magnetohidrodinâmica, pode-se obter vínculos sob os quais o propulsor pudesse ser construído. O mais forte destes é o que dita a topologia do campo magnético. Sendo assim, foram realizadas simulações computacionais, que definiram a geometria do propulsor. Após construído, este foi diagnosticado usando-se sondas de Langmuir e analisadores de energia. Como resultados, obtivemos a distribuição espacial da temperatura, densidade e potencial do plasma, bem como a distribuição angular do feixe produzido pelo mesmo em vários regimes de operação. O espectro de energia do feixe de plasma também foi medido, indicando íons de até 560eV. Combinando estes resultados, calculou-se o empuxo do propulsor: 84mN; e o impulso específico: 1083s. Estes demonstram que o mesmo estará qualificado, num futuro próximo, para o emprego no controle de atitude de satélites científicos, ou até mesmo como parte do conjunto propulsor primário, responsáveis pela transferência de órbitas.

  11. Experimental evaluation of pumpjet propulsor for an axi-symmetric body in wind tunnel

    NASA Astrophysics Data System (ADS)

    Suryanarayana, Ch.; Satyanarayana, B.; Ramji, K.; Saiju, A.

    2010-03-01

    Design of a Pump-Jet Propulsor (PJP) was undertaken for an underwater body with axi-symmetric configuration using axial flow compressor design techniques supported by CFD analysis for performance prediction. Experimental evaluation of the PJP was carried out through experiments in Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminium alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle in water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Generation After Next Propulsor Research: Robust Design for Embedded Engine Systems

    NASA Technical Reports Server (NTRS)

    Arend, David J.; Tillman, Gregory; O'Brien, Walter F.

    2012-01-01

    The National Aeronautics and Space Administration, United Technologies Research Center and Virginia Polytechnic and State University have contracted to pursue multi-disciplinary research into boundary layer ingesting (BLI) propulsors for generation after next environmentally responsible subsonic fixed wing aircraft. This Robust Design for Embedded Engine Systems project first conducted a high-level vehicle system study based on a large commercial transport class hybrid wing body aircraft, which determined that a 3 to 5 percent reduction in fuel burn could be achieved over a 7,500 nanometer mission. Both pylon-mounted baseline and BLI propulsion systems were based on a low-pressure-ratio fan (1.35) in an ultra-high-bypass ratio engine (16), consistent with the next generation of advanced commercial turbofans. An optimized, coupled BLI inlet and fan system was subsequently designed to achieve performance targets identified in the system study. The resulting system possesses an inlet with total pressure losses less than 0.5%, and a fan stage with an efficiency debit of less than 1.5 percent relative to the pylon-mounted, clean-inflow baseline. The subject research project has identified tools and methodologies necessary for the design of next-generation, highly-airframe-integrated propulsion systems. These tools will be validated in future large-scale testing of the BLI inlet / fan system in NASA's 8 foot x 6 foot transonic wind tunnel. In addition, fan unsteady response to screen-generated total pressure distortion is being characterized experimentally in a JT15D engine test rig. These data will document engine sensitivities to distortion magnitude and spatial distribution, providing early insight into key physical processes that will control BLI propulsor design.

  14. Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 5: Unsteady counterrotation ducted propfan analysis

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Delaney, Robert A.

    1993-01-01

    The primary objective of this study was the development of a time-marching three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict steady and unsteady compressible transonic flows about ducted and unducted propfan propulsion systems employing multiple blade rows. The computer codes resulting from this study are referred to as ADPAC-AOAR\\CR (Advanced Ducted Propfan Analysis Codes-Angle of Attack Coupled Row). This document is the final report describing the theoretical basis and analytical results from the ADPAC-AOACR codes developed under task 5 of NASA Contract NAS3-25270, Unsteady Counterrotating Ducted Propfan Analysis. The ADPAC-AOACR Program is based on a flexible multiple blocked grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. For convenience, several standard mesh block structures are described for turbomachinery applications. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. Numerical calculations are compared with experimental data for several test cases to demonstrate the utility of this approach for predicting the aerodynamics of modern turbomachinery configurations employing multiple blade rows.

  15. Field Test of Advanced Duct-Sealing Technologies Within the Weatherization Assistance Program

    SciTech Connect

    Ternes, MP

    2001-12-05

    A field test of an aerosol-spray duct-sealing technology and a conventional, best-practice approach was performed in 80 homes to determine the efficacy and programmatic needs of the duct-sealing technologies as applied in the U.S. Department of Energy Weatherization Assistance Program. The field test was performed in five states: Iowa, Virginia, Washington, West Virginia, and Wyoming. The study found that, compared with the best-practice approach, the aerosol-spray technology is 50% more effective at sealing duct leaks and can potentially reduce labor time and costs for duct sealing by 70%, or almost 4 crew-hours. Further study to encourage and promote use of the aerosol-spray technology within the Weatherization Assistance Program is recommended. A pilot test of full production weatherization programs using the aerosol-spray technology is recommended to develop approaches for integrating this technology with other energy conservation measures and minimizing impacts on weatherization agency logistics. In order to allow or improve adoption of the aerosol spray technology within the Weatherization Assistance Program, issues must be addressed concerning equipment costs, use of the technology under franchise arrangements with Aeroseal, Inc. (the holders of an exclusive license to use this technology), software used to control the equipment, safety, and training. Application testing of the aerosol-spray technology in mobile homes is also recommended.

  16. Duct wall impedance control as an advanced concept for acoustic suppression enhancement. [engine noise reduction

    NASA Technical Reports Server (NTRS)

    Dean, P. D.

    1978-01-01

    A systems concept procedure is described for the optimization of acoustic duct liner design for both uniform and multisegment types. The concept was implemented by the use of a double reverberant chamber flow duct facility coupled with sophisticated computer control and acoustic analysis systems. The optimization procedure for liner insertion loss was based on the concept of variable liner impedance produced by bias air flow through a multilayer, resonant cavity liner. A multiple microphone technique for in situ wall impedance measurements was used and successfully adapted to produce automated measurements for all liner configurations tested. The complete validation of the systems concept was prevented by the inability to optimize the insertion loss using bias flow induced wall impedance changes. This inability appeared to be a direct function of the presence of a higher order energy carrying modes which were not influenced significantly by the wall impedance changes.

  17. Stator-Induced Circumferentially-Varying Preswirl Propulsor

    NASA Astrophysics Data System (ADS)

    Farnsworth, John; Amitay, Michael; Beal, David; Huyer, Stephen

    2008-11-01

    A propuslor capable of producing maneuvering forces in all directions effectively eliminates the need for additional control surfaces. Side forces can be generated by the propeller through the variation of the inflow swirl velocity to a conventional propeller. These control forces are generated based on the same geometric principles as a helicopter swash-plate. Instead of cyclically adjusting the propeller blade pitch angle, the relative pitch angle of a fixed pitch propeller is cyclically altered through a preswirled inflow generated by an upstream stator row. Experiments were conducted in a wind tunnel to quantify the effectiveness of an upstream stator row to generate a circumferentially varying swirled flow. Global flow measurements were acquired through static pressure and PIV measurements on a simplified propulsor model. From these and future measurements a full understanding of the fluidic interactions associated with the non-uniform upstream stator row and the propeller can be made.

  18. Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 2: Unsteady ducted propfan analysis computer program users manual

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Delaney, Robert A.; Bettner, James L.

    1991-01-01

    The primary objective of this study was the development of a time-dependent three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict unsteady compressible transonic flows about ducted and unducted propfan propulsion systems at angle of attack. The computer codes resulting from this study are referred to as Advanced Ducted Propfan Analysis Codes (ADPAC). This report is intended to serve as a computer program user's manual for the ADPAC developed under Task 2 of NASA Contract NAS3-25270, Unsteady Ducted Propfan Analysis. Aerodynamic calculations were based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. A time-accurate implicit residual smoothing operator was utilized for unsteady flow predictions. For unducted propfans, a single H-type grid was used to discretize each blade passage of the complete propeller. For ducted propfans, a coupled system of five grid blocks utilizing an embedded C-grid about the cowl leading edge was used to discretize each blade passage. Grid systems were generated by a combined algebraic/elliptic algorithm developed specifically for ducted propfans. Numerical calculations were compared with experimental data for both ducted and unducted propfan flows. The solution scheme demonstrated efficiency and accuracy comparable with other schemes of this class.

  19. Bubble Augmented Propulsor Mixture Flow Simulation near Choked Flow Condition

    NASA Astrophysics Data System (ADS)

    Choi, Jin-Keun; Hsiao, Chao-Tsung; Chahine, Georges

    2013-03-01

    The concept of waterjet thrust augmentation through bubble injection has been the subject of many patents and publications over the past several decades, and computational and experimental evidences of the augmentation of the jet thrust through bubble growth in the jet stream have been reported. Through our experimental studies, we have demonstrated net thrust augmentation as high as 70%for air volume fractions as high as 50%. However, in order to enable practical designs, an adequately validated modeling tool is required. In our previous numerical studies, we developed and validated a numerical code to simulate and predict the performance of a two-phase flow water jet propulsion system for low void fractions. In the present work, we extend the numerical method to handle higher void fractions to enable simulations for the high thrust augmentation conditions. At high void fractions, the speed of sound in the bubbly mixture decreases substantially and could be as low as 20 m/s, and the mixture velocity can approach the speed of sound in the medium. In this numerical study, we extend our numerical model, which is based on the two-way coupling between the mixture flow field and Lagrangian tracking of a large number of bubbles, to accommodate compressible flow regimes. Numerical methods used and the validation studies for various flow conditions in the bubble augmented propulsor will be presented. This work is supported by Office of Naval Research through contract N00014-11-C-0482 monitored by Dr. Ki-Han Kim.

  20. An introduction to the design of marine propulsors

    NASA Technical Reports Server (NTRS)

    Henderson, R. E.

    1974-01-01

    A summary of methods for marine propulsion design is presented. A list of reports dealing with the design of open propellers, ducted propellers or pumpjets, and waterjets is included. The major problems involved in marine propulsion design are discussed.

  1. Trastuzumab in Treating Patients With Locally Advanced or Metastatic Gallbladder Cancer or Bile Duct Cancer That Cannot Be Removed by Surgery

    ClinicalTrials.gov

    2014-05-15

    Adenocarcinoma of the Extrahepatic Bile Duct; Adenocarcinoma of the Gallbladder; Malignant Neoplasm; Recurrent Extrahepatic Bile Duct Cancer; Recurrent Gallbladder Cancer; Unresectable Extrahepatic Bile Duct Cancer; Unresectable Gallbladder Cancer

  2. Lensing duct

    DOEpatents

    Beach, Raymond J. , Benett

    1994-01-01

    A lensing duct to condense (intensify) light using a combination of front surface lensing and reflective waveguiding. The duct tapers down from a wide input side to a narrow output side, with the input side being lens-shaped and coated with an antireflective coating for more efficient transmission into the duct. The four side surfaces are uncoated, preventing light from escaping by total internal reflection as it travels along the duct (reflective waveguiding). The duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials, and can be fabricated from inexpensive glass and plastic.

  3. Locomotion with flexible propulsors: I. Experimental analysis of pectoral fin swimming in sunfish.

    PubMed

    Lauder, George V; Madden, Peter G A; Mittal, Rajat; Dong, Haibo; Bozkurttas, Meliha

    2006-12-01

    A full understanding of the mechanics of locomotion can be achieved by incorporating descriptions of (1) three-dimensional kinematics of propulsor movement, (2) material properties of the propulsor, (3) power input and control and (4) the fluid dynamics effects of propulsor motion into (5) a three-dimensional computational framework that models the complexity of propulsors that deform and change area. In addition, robotic models would allow for further experimental investigation of changes to propulsor design and for testing of hypothesized relationships between movement and force production. Such a comprehensive suite of data is not yet available for any flexible propulsor. In this paper, we summarize our research program with the goal of producing a comprehensive data set for each of the five components noted above through a study of pectoral fin locomotion in one species of fish: the bluegill sunfish Lepomis macrochirus. Many fish use pectoral fins exclusively for locomotion, and pectoral fins in most fish are integral to generating force during maneuvering. Pectoral fins are complex structures composed of jointed bony supports that are under active control via pectoral fin musculature. During propulsion in sunfish, the fin deforms considerably, has two leading edges, and sunfish can rotate the whole fin or just control individual sections to vector thrust. Fin material properties vary along the length of fin rays and among rays. Experimental fluid dynamic analysis of sunfish pectoral fin locomotion reveals that the fin generates thrust throughout the fin beat cycle, and that the upper and lower edges each produce distinct simultaneous leading edge vortices. The following companion paper provides data on the computational approach taken to understand locomotion using flexible pectoral fins. PMID:17671315

  4. Particle deposition in ventilation ducts

    SciTech Connect

    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. 3-D viscous flow CFD analysis of the propeller effect on an advanced ducted propeller subsonic inlet

    NASA Technical Reports Server (NTRS)

    Iek, Chanthy; Boldman, Donald R.; Ibrahim, Mounir

    1993-01-01

    The time-marching Navier-Stokes code PARC3D was used to study the 3D viscous flow associated with an advanced ducted propeller subsonic inlet at take-off operating conditions. At a free stream Mach number of 0.2, experimental data for the inlet-with-propeller test model indicated that the airflow was attached on the cowl windward lip at an angle of attack of 25 deg became unstable at 29 deg, and separated at 30 deg. An experimental study with a similar inlet and without propeller (through-flow) indicated that flow separation occurred at an angle of attack a few degrees below the value observed when the inlet was tested with the propeller, indicating the propeller's favorable effect on inlet performance. In the present numerical study, flow blockage analogous to the propeller was modeled via a PARC3D computational boundary condition (BC), the 'screen BC', based on 1-1/2 dimension actuator disk theory. The application of the screen BC in this numerical study provided results similar to those of past experimental efforts in which either the blockage device or the propeller was used.

  6. Advanced in-duct sorbent injection for SO{sub 2} control. Topical report No. 4, Task 3, Optimized advanced process evaluation

    SciTech Connect

    Rosenhoover, W.A.; Stouffer, M.R.; Maskew, J.T.; Withum, J.A.; Wu, M.M.; Winschel, R.A.

    1994-12-01

    The objective of this research project is to develop second- generation duct injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Specific performance targets are 90% SO{sup 2} removal and 60% sorbent utilization efficiency. Research focused on the Advanced Coolside process, which showed the potential for exceeding these targets. The objective of Subtask 3.1, Performance Testing, was to develop process performance and operability data for design and scale-up of the optimized Advance Coolside process. Results of long-term pilot plant testing with 24 hour/day operation provided a positive indication of process operability. The objective of Subtask 3.2, Waste Characterization, was to determine the chemical and physical properties of the waste materials for designing the waste handling and disposal systems for the process. Test results show that the combined spent sorbent and fly ash waste is suitable for landfilling. Further, the waste management study indicated a potential for by-product utilization for synthetic aggregate production; a more thorough investigation of this potential is required.

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

    NASA Technical Reports Server (NTRS)

    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. The 3-D viscous flow CFD analysis of the propeller effect on an advanced ducted propeller subsonic inlet

    NASA Technical Reports Server (NTRS)

    Iek, Chanthy; Boldman, Donald R.; Ibrahim, Mounir

    1993-01-01

    A time marching Navier-Stokes code called PARC3D was used to study the 3-D viscous flow associated with an advanced ducted propeller (ADP) subsonic inlet at take-off operating conditions. At a free stream Mach number of 0.2, experimental data for the inlet-with-propeller test model indicated that the airflow was attached on the cowl windward lip at an angle of attack of 25 degrees became unstable at 29 degrees, and separated at 30 degrees. An experimental study with a similar inlet and with no propeller (through-flow) indicated that flow separation occurred at an angle of attack a few degrees below the value observed when the inlet was tested with the propeller. This tends to indicate that the propeller exerts a favorable effect on the inlet performance. During the through-flow experiment a stationary blockage device was used to successfully simulate the propeller effect on the inlet flow field at angles of attack. In the present numerical study, this flow blockage was modeled via a PARC3D computational boundary condition (BC) called the screen BC. The principle formulation of this BC was based on the one-and-half dimension actuator disk theory. This screen BC was applied at the inlet propeller face station of the computational grid. Numerical results were obtained with and without the screen BC. The application of the screen BC in this numerical study provided results which are similar to the results of past experimental efforts in which either the blockage device or the propeller was used.

  9. Duct closure

    DOEpatents

    Vowell, Kennison L.

    1987-01-01

    A closure for an inclined duct having an open upper end and defining downwardly extending passageway. The closure includes a cap for sealing engagement with the open upper end of the duct. Associated with the cap are an array of vertically aligned plug members, each of which has a cross-sectional area substantially conforming to the cross-sectional area of the passageway at least adjacent the upper end of the passageway. The plug members are interconnected in a manner to provide for free movement only in the plane in which the duct is inclined. The uppermost plug member is attached to the cap means and the cap means is in turn connected to a hoist means which is located directly over the open end of the duct.

  10. Fabrication process of a high temperature polymer matrix engine duct

    NASA Technical Reports Server (NTRS)

    Pratt, R. D.; Wilson, A. J.

    1985-01-01

    The process that was used in the molding of an advanced composite outer by-pass duct planned for the F404 engine is discussed. This duct was developed as a potential replacement for the existing titanium duct in order to reduce both the weight and cost of the duct. The composite duct is now going into the manufacturing technology portion of the program. The duct is fabricated using graphite cloth impregnated with the PMR-15 matrix system.

  11. Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 5: Unsteady counterrotation ducted propfan analysis. Computer program user's manual

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Delaney, Robert A.; Adamczyk, John J.; Miller, Christopher J.; Arnone, Andrea; Swanson, Charles

    1993-01-01

    The primary objective of this study was the development of a time-marching three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict steady and unsteady compressible transonic flows about ducted and unducted propfan propulsion systems employing multiple blade rows. The computer codes resulting from this study are referred to as ADPAC-AOACR (Advanced Ducted Propfan Analysis Codes-Angle of Attack Coupled Row). This report is intended to serve as a computer program user's manual for the ADPAC-AOACR codes developed under Task 5 of NASA Contract NAS3-25270, Unsteady Counterrotating Ducted Propfan Analysis. The ADPAC-AOACR program is based on a flexible multiple blocked grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. For convenience, several standard mesh block structures are described for turbomachinery applications. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. Numerical calculations are compared with experimental data for several test cases to demonstrate the utility of this approach for predicting the aerodynamics of modern turbomachinery configurations employing multiple blade rows.

  12. Thrust performance of unsteady propulsors using a novel measurement system, and corresponding wake patterns

    PubMed Central

    Clark, Richard P.; Smits, Alexander J.

    2009-01-01

    An apparatus is described for the measurement of unsteady thrust and propulsive efficiency produced by biologically inspired oscillating hydrodynamic propulsors. Force measurement is achieved using a strain-gauge-based force transducer, augmented with a lever to amplify or attenuate the applied force and control the measurement sensitivity and natural frequency of vibration. The lever can be used to tune the system to a specific application and it is shown that, using the lever, the stiffness can be made to increase more rapidly than the measurement sensitivity decreases. Efficiency is computed from measurements of the time-averaged power imparted to the fluid. The apparatus is applied to two different propulsors, demonstrating the versatility of the system; wake visualizations are examined, which provide insight into the physical mechanisms of efficient propulsion. PMID:19946574

  13. The role of spanwise-flexible propulsors in swimming and flying

    NASA Astrophysics Data System (ADS)

    Wong, Jaime; Rival, David

    2015-11-01

    Natural swimmers and flyers span several orders of magnitude in both Reynolds number and fluid-propulsor mass ratio. Intuitively, one would expect different aeroelastic strategies to be employed across these regimes. However, similar magnitudes of spanwise bending, as measured by flexion angle, have been observed across this entire range for cruise conditions. In this study, it is hypothesized that propulsor flexion has converged to generate similar spanwise vorticity transport in order to control the dynamic-stall vortex ubiquitous in natural swimming and flight. In particular, it is believed that vorticity convection and vortex stretching delay vortex detachment by balancing vorticity generated at the leading-edge and by reducing the overall vortex size, respectively, as recently shown for flapping profiles. Moving forward, passive spanwise flexibility of propulsors is now abstracted as a spanwise-variation in effective incidence. This abstraction is realized as a pitching-flapping motion. By comparing passively flexible cases to rigid cases, the role of flexibility on controlling vorticity transport, and thus delaying vortex detachment is elucidated.

  14. Advanced in-duct sorbent injection for SO{sub 2} control. Topical report No. 6, Task 5: Conceptual commercial process design and economic evaluation

    SciTech Connect

    Deluliis, N.J.; Maskew, J.T.

    1994-12-01

    The objective of this research project is the development of a second generation in-duct sorbent injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Research focused on the Advanced Coolside Process, which has shown the potential of exceeding the performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. In Task 5, Conceptual Process Design and Economic Evaluation, the economics of the CONSOL Advanced Coolside Process as a Clean Air Act compliance option were evaluated. A conceptual process design for full-scale, coal-fired applications is described. Advanced Coolside is compared to conventional Limestone Forced Oxidation (LSFO) wet FGD technology. The process economics for coal sulfur levels ranging from 1.0% to 3.5% (as-received) and plant sizes ranging from 160 to 512 gross MW were investigated, In addition, the economics of on-site versus off-site lime hydration and the cost sensitivity to delivered pebble lime and hydrate prices are investigated, Advanced in-duct sorbent injection enjoys a capital and levelized cost advantage relative to LSFO in all cases examined in this study. As a result of this study and others made during this contract, the following conclusions can be made: (1) The capital cost of Advanced Coolside is 55% to 60% less than that of LSFO and varies slightly depending on coal sulfur content and plant size. (2) The total levelized SO{sub 2} control cost advantage relative to LSFO varies from 15% to 35% over the range of coal sulfur contents and plant sizes evaluated. This cost advantage is sensitive to sorbent transportation charges. As a result, the economics are site-specific. (3) The experimental optimizations based on interim economic analyses were the key to capital and levelized cost reductions.

  15. Complicated bile duct stones

    PubMed Central

    Roy, Ashwin; Martin, Derrick

    2013-01-01

    Common bile duct stones (CBDSs) are solid deposits that can either form within the gallbladder or migrate to the common bile duct (CBD), or form de novo in the biliary tree. In the USA around 15% of the population have gallstones and of these, 3% present with symptoms annually. Because of this, there have been major advancements in the management of gallstones and related conditions. Management is based on the patient's risk profile; young and healthy patients are likely to be recommended for surgery and elderly patients with comorbidities are usually recommended for endoscopic procedures. Imaging of gallstones has advanced in the last 30 years with endoscopic retrograde cholangiopancreatography evolving from a diagnostic to a therapeutic procedure in removing CBDSs. We present a complicated case of a patient with a CBDS and periampullary diverticulum and discuss the techniques used to diagnose and remove the stone from the biliary system. PMID:23946532

  16. Comprehensive Report of Fan Performance From Duct Rake Instrumentation on 1.294 Pressure Ratio, 806 ft/sec Tip Speed Turbofan Simulator Models

    NASA Technical Reports Server (NTRS)

    Jeracki, Robert J.

    2006-01-01

    A large scale model representative of an advanced ducted propulsor-type, low-noise, very high bypass ratio turbofan engine was tested for acoustics, aerodynamic performance, and off-design operability in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel. The test was part of NASA s Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and un-powered core passage were simulated. As might be expected, the effect of stall management casing treatment was a performance penalty. Reducing the recirculating flow at the fan tip reduced the penalty while still providing sufficient stall margin. Two fans were tested with the same aerodynamic design; one with graphite composite material, and the other with solid titanium. There were surprising performance differences between the two fans, though both blades showed some indication of transitional flow near the tips. Though the pressure and temperature ratios were low for this fan design, the techniques used to improve thermocouple measurement accuracy gave repeatable data with adiabatic efficiencies agreeing within 1 percent. The measured fan adiabatic efficiency at simulated takeoff conditions was 93.7 percent and matched the design intent.

  17. Advanced in-duct sorbent injection for SO{sub 2} control. Topical report number 3, Subtask 2.3: Sorbent optimization

    SciTech Connect

    Rosenhoover, W.A.; Maskew, J.T.; Withum, J.A.; Stouffer, M.R.

    1994-11-01

    The objective of this research project is to develop second-generation duct injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Specific process performance goals are to achieve 90% SO{sub 2} removal and 60% sorbent utilization efficiency. Research is focused on the Advanced Coolside process, which has shown the potential of achieving these targets. The objective of Subtask 2.3, Sorbent Optimization, was to explore means of improving performance and economics of the Advanced Coolside process through optimizing the sorbent system. Pilot plant tests of commercial and specially prepared hydrated limes showed that the process is relatively insensitive to sorbent source. This can be an important economic advantage, allowing the use of the lowest cost sorbent available at a site. A pilot plant hydration study conducted in cooperation with Dravo Lime Company further indicated the relative insensitivity of process performance to lime source and to lime physical properties. Pilot plant tests indicated that the use of very small amounts of additives in the Advanced Coolside process can improve performance under some circumstances; however, additives are not necessary to exceed process performance targets.

  18. Overview of ERA Ultra High Bypass Propulsor Technology Development

    NASA Technical Reports Server (NTRS)

    Hughes, Christopher

    2011-01-01

    A review of the current research being conducted under the Environmentally Responsible Aviation (ERA) Ultra High Bypass (UHB) Testing subelement is presented. The four exiting tasks under the subelement, a description of each task, and the current status of each are given. The four tasks are: 1. Collaborate with P&W to design, fabricate and test a second generation of Geared Turbofan 2. Design, fabricate and test advanced Over the Rotor acoustic treatment and acoustically treated Soft Vanes 3. Develop a Shape Memory Alloy Variable Area Nozzle concept and demonstrate prototype 4. Refurbish and update the GRC Ultra High Bypass Drive Rig Following the current task updates, an overview of three proposed additional tasks to support the existing tasks is presented. The additional tasks would allow noise reduction and noise diagnostic testing technologies to be demonstrated at TRL 4 as part of existing planned fan model testing in the NASA Glenn 9 x15 Low Speed Wind Tunnel under the ERA UHB Testing subelement.

  19. Efficacy and Safety of Endoscopic Papillary Large Balloon Dilation for Removal of Large Bile Duct Stones in Advanced Age

    PubMed Central

    Kim, Kook Hyun

    2016-01-01

    Objective. Bile duct stone-related adverse events can be detrimental in the elderly. However, little is known about clinical outcomes and adverse events following endoscopic papillary large balloon dilation (EPLBD) in the elderly. The aim of this study was to evaluate the safety and feasibility of EPLBD for the removal of CBD stones in patients aged ≥ 80 years. Methods. A total of 204 patients who underwent EPLBD from 2006 to 2012 were retrospectively reviewed. Patients were classified into two groups (148 patients < 80 years old, Group A; 56 patients ≥ 80 years old, Group B). Endoscopic findings, clinical outcomes, and adverse events in two groups were compared. Results. The number of underlying chronic diseases in Group B was significantly higher than in Group A (P = 0.032). The rates of overall stone clearance were similar between two groups (P = 0.145). No significant difference with regard to post-ERCP pancreatitis between two groups was observed (P = 0.687). All episodes of pancreatitis had full recovery with conservative treatment. One major hemorrhage in Group A was successfully controlled endoscopically and one death caused by retroperitoneal perforation occurred in Group A. Conclusions. EPLBD appear to be safe and effective for CBD stone removal in patients aged ≥ 80 years. PMID:27812520

  20. Advanced in-duct sorbent injection for SO{sub 2} control. Topical report No. 2, Subtask 2.2: Design optimization

    SciTech Connect

    Rosenhoover, W.A.; Stouffer, M.R.; Withum, J.A.

    1994-12-01

    The objective of this research project is to develop second-generation duct injection technology as a cost-effective SO{sub 2} control option for the 1990 Clean Air Act Amendments. Research is focused on the Advanced Coolside process, which has shown the potential for achieving the performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. In Subtask 2.2, Design Optimization, process improvement was sought by optimizing sorbent recycle and by optimizing process equipment for reduced cost. The pilot plant recycle testing showed that 90% SO{sub 2} removal could be achieved at sorbent utilizations up to 75%. This testing also showed that the Advanced Coolside process has the potential to achieve very high removal efficiency (90 to greater than 99%). Two alternative contactor designs were developed, tested and optimized through pilot plant testing; the improved designs will reduce process costs significantly, while maintaining operability and performance essential to the process. Also, sorbent recycle handling equipment was optimized to reduce cost.

  1. Computation of flows in a turn-around duct and a turbine cascade using advanced turbulence models

    NASA Technical Reports Server (NTRS)

    Lakshminarayana, B.; Luo, J.

    1993-01-01

    Numerical investigation has been carried out to evaluate the capability of the Algebraic Reynolds Stress Model (ARSM) and the Nonlinear Stress Model (NLSM) to predict strongly curved turbulent flow in a turn-around duct (TAD). The ARSM includes the near-wall damping term of pressure-strain correlation phi(sub ij,w), which enables accurate prediction of individual Reynolds stress components in wall flows. The TAD mean flow quantities are reasonably well predicted by various turbulence models. The ARSM yields better predictions for both the mean flow and the turbulence quantities than the NLSM and the k-epsilon (k = turbulent kinetic energy, epsilon = dissipation rate of k) model. The NLSM also shows slight improvement over the k-epsilon model. However, all the models fail to capture the recovery of the flow from strong curvature effects. The formulation for phi(sub ij,w) appears to be incorrect near the concave surface. The hybrid k-epsilon/ARSM, Chien's k-epsilon model, and Coakley's q-omega (q = the square root of k, omega = epsilon/k) model have also been employed to compute the aerodynamics and heat transfer of a transonic turbine cascade. The surface pressure distributions and the wake profiles are predicted well by all the models. The k-epsilon model and the k-epsilon/ARSM model provide better predictions of heat transfer than the q-omega model. The k-epsilon/ARSM solutions show significant differences in the predicted skin friction coefficients, heat transfer rates and the cascade performance parameters, as compared to the k-epsilon model. The k-epsilon/ARSM model appears to capture, qualitatively, the anisotropy associated with by-pass transition.

  2. Hydrodynamic analysis, performance assessment, and actuator design of a flexible tail propulsor in an artificial alligator

    NASA Astrophysics Data System (ADS)

    Philen, Michael; Neu, Wayne

    2011-09-01

    The overall objective of this research is to develop analysis tools for determining actuator requirements and assessing viable actuator technology for design of a flexible tail propulsor in an artificial alligator. A simple hydrodynamic model that includes both reactive and resistive forces along the tail is proposed and the calculated mean thrust agrees well with conventional estimates of drag. Using the hydrodynamic model forces as an input, studies are performed for an alligator ranging in size from 1 cm to 2 m at swimming speeds of 0.3-1.8 body lengths per second containing five antagonistic pairs of actuators distributed along the length of the tail. Several smart materials are considered for the actuation system, and preliminary analysis results indicate that the acrylic electroactive polymer and the flexible matrix composite actuators are potential artificial muscle technologies for the system.

  3. Characterization of microstructure and property evolution in advanced cladding and duct: Materials exposed to high dose and elevated temperature

    DOE PAGES

    Allen, Todd R.; Kaoumi, Djamel; Wharry, Janelle P.; Jiao, Zhijie; Topbasi, Cem; Kohnert, Aaron; Barnard, Leland; Certain, Alicia; Field, Kevin G.; Was, Gary S.; et al

    2015-05-20

    Designing materials for performance in high-radiation fields can be accelerated through a carefully chosen combination of advanced multiscale modeling paired with appropriate experimental validation. Here, the studies reported in this work, the combined efforts of six universities working together as the Consortium on Cladding and Structural Materials, use that approach to focus on improving the scientific basis for the response of ferritic–martensitic steels to irradiation. A combination of modern modeling techniques with controlled experimentation has specifically focused on improving the understanding of radiation-induced segregation, precipitate formation and growth under radiation, the stability of oxide nanoclusters, and the development of dislocationmore » networks under radiation. Experimental studies use both model and commercial alloys, irradiated with both ion beams and neutrons. Lastly, transmission electron microscopy and atom probe are combined with both first-principles and rate theory approaches to advance the understanding of ferritic–martensitic steels.« less

  4. Characterization of microstructure and property evolution in advanced cladding and duct: Materials exposed to high dose and elevated temperature

    SciTech Connect

    Allen, Todd R.; Kaoumi, Djamel; Wharry, Janelle P.; Jiao, Zhijie; Topbasi, Cem; Kohnert, Aaron; Barnard, Leland; Certain, Alicia; Field, Kevin G.; Was, Gary S.; Morgan, Dane L.; Motta, Arthur T.; Wirth, Brian D.; Yang, Y.

    2015-05-20

    Designing materials for performance in high-radiation fields can be accelerated through a carefully chosen combination of advanced multiscale modeling paired with appropriate experimental validation. Here, the studies reported in this work, the combined efforts of six universities working together as the Consortium on Cladding and Structural Materials, use that approach to focus on improving the scientific basis for the response of ferritic–martensitic steels to irradiation. A combination of modern modeling techniques with controlled experimentation has specifically focused on improving the understanding of radiation-induced segregation, precipitate formation and growth under radiation, the stability of oxide nanoclusters, and the development of dislocation networks under radiation. Experimental studies use both model and commercial alloys, irradiated with both ion beams and neutrons. Lastly, transmission electron microscopy and atom probe are combined with both first-principles and rate theory approaches to advance the understanding of ferritic–martensitic steels.

  5. Ducted electromagnetic waves in the Martian ionosphere detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding radar

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenfei; Orosei, Roberto; Huang, Qian; Zhang, Jie

    2016-07-01

    In the data of the Mars Advanced Radar for Subsurface and Ionosphere Sounding on board the European Space Agency (ESA) mission Mars Express (MEX), a distinctive type of signals (called the "epsilon signature"), which is similar to that previously detected during radio sounding of the terrestrial F region ionosphere, is found. The signature is interpreted to originate from multiple reflections of electromagnetic waves propagating along sounder pulse-created, crustal magnetic field-aligned plasma bubbles (waveguides). The signatures have a low (below 0.5%) occurrence rate and apparent cutoff frequencies 3-5 times higher than the theoretical one for an ordinary mode wave. These properties are explained by the influence of the perpendicular ionospheric plasma density gradient and the sounder pulse frequency on the formation of waveguides.

  6. Future Treatment of Common Bile Duct Stones.

    PubMed

    Johnson; Hunter

    1997-03-01

    Management options for patients found to have common bile duct stones have expanded as a function of improved instrumentation and radiographic support. Technological advances initially lead to increased costs but eventually result in improved quality for patients. Controversy exists for patients with either soft clinical findings or stones found at the time of laparoscopic cholecystectomy. As laparoscopic common duct exploration becomes more widespread the need for perioperative ERCP will likely decrease; however, this will depend on the experience of the surgeons at a given institution. Common bile duct stones found at the time of laparoscopic cholecystectomy can be approached in a variety of different ways. The most commonly used methods are laparoscopic transcystic common bile duct exploration, laparoscopic choledochotomy with common bile duct exploration, open common bile duct exploration, laparoscopic antegrade sphincterotomy, and postoperative ERCP. In the future, the treatment goal of biliary lithiasis will be to accomplish cholecystectomy and removal of bile duct stones in a single stage. Advances in fiberoptic technology will make transcystic duct exploration more effective, but it is likely that sphincterotomy (antegrade or retrograde) will be used preferentially for the distally impacted stone.

  7. Laparoscopic common bile duct exploration.

    PubMed

    Vecchio, Rosario; MacFadyen, Bruce V

    2002-04-01

    In recent years, laparoscopic common bile duct exploration has become the procedure of choice in the management of choledocholithiasis in several laparoscopic centers. The increasing interest for this laparoscopic approach is due to the development of instrumentation and technique, allowing the procedure to be performed safely, and it is also the result of the revised role of endoscopic retrograde cholangiopancreatography, which has been questioned because of its cost, risk of complications and effectiveness. Many surgeons, however, are still not familiar with this technique. In this article we discuss the technique and results of laparoscopic common bile duct exploration. Both the laparoscopic transcystic approach and choledochotomy are discussed, together with the results given in the literature. When one considers the costs, morbidity, mortality and the time required before the patient can return to work, it would appear that laparoscopic cholecystectomy with common bile duct exploration is more favorable than open surgery or laparoscopic cholecystectomy with preoperative or postoperative endoscopic sphincterotomy. However, the technique requires advanced laparoscopic skills, including suturing, knot tying, the use of a choledochoscope, guidewire, dilators and balloon stone extractor. Although laparoscopic common bile duct exploration appears to be the most cost-effective method to treat common bile duct stones, it should be emphasized that this procedure is very challenging, and it should be performed by well-trained laparoscopic surgeons with experience in biliary surgery. PMID:11981684

  8. Hollow lensing duct

    DOEpatents

    Beach, Raymond J.; Honea, Eric C.; Bibeau, Camille; Mitchell, Scott; Lang, John; Maderas, Dennis; Speth, Joel; Payne, Stephen A.

    2000-01-01

    A hollow lensing duct to condense (intensify) light using a combination of focusing using a spherical or cylindrical lens followed by reflective waveguiding. The hollow duct tapers down from a wide input side to a narrow output side, with the input side consisting of a lens that may be coated with an antireflective coating for more efficient transmission into the duct. The inside surfaces of the hollow lens duct are appropriately coated to be reflective, preventing light from escaping by reflection as it travels along the duct (reflective waveguiding). The hollow duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials.

  9. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term Irradiation at Elevated Temperature: Critical Experiments

    SciTech Connect

    Was, Gary; Jiao, Zhijie; Allen, Todd; Yang, Yong

    2013-12-20

    The in-service degradation of reactor core materials is related to underlying changes in the irradiated microstructure. During reactor operation, structural components and cladding experience displacement of atoms by collisions with neutrons at temperatures at which the radiation-induced defects are mobile, leading to microstructure evolution under irradiation that can degrade material properties. At the doses and temperatures relevant to fast reactor operation, the microstructure evolves by microchemistry changes due to radiation-induced segregation, dislocation loop formation and growth, radiation induced precipitation, destabilization of the existing precipitate structure, as well as the possibility for void formation and growth. These processes do not occur independently; rather, their evolution is highly interlinked. Radiation-induced segregation of Cr and existing chromium carbide coverage in irradiated alloy T91 track each other closely. The radiation-induced precipitation of Ni-Si precipitates and RIS of Ni and Si in alloys T91 and HCM12A are likely related. Neither the evolution of these processes nor their coupling is understood under the conditions required for materials performance in fast reactors (temperature range 300-600°C and doses to 200 dpa and beyond). Further, predictive modeling is not yet possible, as models for microstructure evolution must be developed along with experiments to characterize these key processes and provide tools for extrapolation. To extend the range of operation of nuclear fuel cladding and structural materials in advanced nuclear energy and transmutation systems to that required for the fast reactor, the irradiation-induced evolution of the microstructure, microchemistry, and the associated mechanical properties at relevant temperatures and doses must be understood. This project builds upon joint work at the proposing institutions, under a NERI-C program that is scheduled to end in September, to understand the effects of

  10. Salivary duct stones

    MedlinePlus

    Spit (saliva) is produced by the salivary glands in the mouth. The chemicals in saliva can form a hard crystal that can block the salivary ducts. When saliva cannot exit a blocked duct, it backs up ...

  11. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term and Elevated Temperature Irradiation: Modeling and Experimental Investigation

    SciTech Connect

    Wirth, Brian; Morgan, Dane; Kaoumi, Djamel; Motta, Arthur

    2013-12-01

    irradiation. This project will focus on modeling microstructural and microchemical evolution of irradiated alloys by performing detailed modeling of such microstructure evolution processes coupled with well-designed in situ experiments that can provide validation and benchmarking to the computer codes. The broad scientific and technical objectives of this proposal are to evaluate the microstructure and microchemical evolution in advanced ferritic/martensitic and oxide dispersion strengthened (ODS) alloys for cladding and duct reactor materials under long-term and elevated temperature irradiation, leading to improved ability to model structural materials performance and lifetime. Specifically, we propose four research thrusts, namely Thrust 1: Identify the formation mechanism and evolution for dislocation loops with Burgers vector of a<100> and determine whether the defect microstructure (predominately dislocation loop/dislocation density) saturates at high dose. Thrust 2: Identify whether a threshold irradiation temperature or dose exists for the nucleation of growing voids that mark the beginning of irradiation-induced swelling, and begin to probe the limits of thermal stability of the tempered Martensitic structure under irradiation. Thrust 3: Evaluate the stability of nanometer sized Y- Ti-O based oxide dispersion strengthened (ODS) particles at high fluence/temperature. Thrust 4: Evaluate the extent to which precipitates form and/or dissolve as a function of irradiation temperature and dose, and how these changes are driven by radiation induced segregation and microchemical evolutions and determined by the initial microstructure.

  12. Bile duct stricture

    MedlinePlus

    ... bile duct Damage or scarring after gallbladder removal Pancreatitis Primary sclerosing cholangitis ... your health care provider if symptoms recur after pancreatitis, cholecystectomy , or other biliary surgery.

  13. Lightweight Valve Closes Duct Quickly

    NASA Technical Reports Server (NTRS)

    Fournier, Walter L.; Burgy, N. Frank

    1991-01-01

    Expanding balloon serves as lightweight emergency valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet valve capable of closing duct of equal diameter.

  14. Duct Tape Durability Testing

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.

    2004-04-01

    Duct leakage is a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums, or branches in the duct system. At each of these connections, a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have shown that taped seals tend to fail over extended periods of time. The Lawrence Berkeley National Laboratory (LBNL) has been testing sealant durability for several years using accelerated test methods and found that typical duct tape (i.e., cloth-backed tapes with natural rubber adhesives) fails more rapidly than other duct sealants. This report summarizes the results of duct sealant durability testing over two years for four UL 181B-FX listed duct tapes (two cloth tapes, a foil tape and an Oriented Polypropylene (OPP) tape). One of the cloth tapes was specifically developed in collaboration with a tape manufacturer to perform better in our durability testing. The tests involved the aging of common ''core-to-collar joints'' of flexible duct to sheet metal collars. Periodic air leakage tests and visual inspection were used to document changes in sealant performance. After two years of testing, the flex-to-collar connections showed little change in air leakage, but substantial visual degradation from some products. A surprising experimental result was failure of most of the clamps used to mechanically fasten the connections. This indicates that the durability of clamps also need to be addressed ensure longevity of the duct connection. An accelerated test method developed during this study has been used as the basis for an ASTM standard (E2342-03).

  15. Low loss duct burner

    SciTech Connect

    Mar, H. M.; Reider, S. B.

    1985-07-09

    A jet propulsion engine with a fan bypass duct includes a duct burner with a plurality of flame stabilizers therein each mounted to inner case and outer case members through spherical bearings. Each of the stabilizers consists of two blade members having integral arms thereon actuated by fore and aft motion of an external actuating ring to assume an expanded position to increase duct turbulence for mixing air flow therethrough with a fuel supply and into a retracted position against each other to reduce pressure drop under nonafterburning operation. Each of the flame stabilizer blades has a platform that controls communication between a hot air source and a duct for improving fuel vaporization during afterburner operation thereby to increase afterburning limits; the platforms close communication between the hot air source and the duct during nonafterburning operation when flame stabilization is not required.

  16. The Potential Benefits of Advanced Casing Treatment for Noise Attenuation in Utra-High Bypass Ratio Turbofan Engines

    NASA Technical Reports Server (NTRS)

    Elliott, David

    2007-01-01

    In order to increase stall margin in a high-bypass ratio turbofan engine, an advanced casing treatment was developed that extracted a small amount of flow from the casing behind the fan and injected it back in front of the fan. Several different configurations of this casing treatment were designed by varying the distance of the extraction and injection points, as well as varying the amount of flow. These casing treatments were tested on a 55.9 cm (22 in.) scale model of the Pratt & Whitney Advanced Ducted Propulsor in the NASA Glenn 9 by 15 Low Speed Wind Tunnel. While all of the casing treatment configurations showed the expected increase in stall margin, a few of the designs showed a potential noise benefit for certain engine speeds. This paper will show the casing treatments and the results of the testing as well as propose further research in this area. With better prediction and design techniques, future casing treatment configurations could be developed that may result in an optimized casing treatment that could conceivably reduce the noise further.

  17. Mean velocity and moments of turbulent velocity fluctuations in the wake of a model ship propulsor

    NASA Astrophysics Data System (ADS)

    Pêgo, J. P.; Lienhart, H.; Durst, F.

    2007-08-01

    ; Schneekluth and Bertram in Ship design for efficiency and economy, 1998), the co-rotating propellers model showed a much stronger swirl in the wake of the propulsor. The anisotropy of turbulence was analyzed using the anisotropy tensor introduced by Lumley and Newman (J Fluid Mech 82(1):161-178, 1977). The invariants of the anisotropy tensor of the wake flow were computed and were plotted in the Lumley-Newman-diagram. These measurements revealed that the anisotropy tensor in the wake of ship propellers is located near to the borders of the invariant map, showing a large degree of anisotropy. They will be presented and will be discussed with respect to applications of turbulence models to predict swirling flows.

  18. Subsonic aerodynamic characteristic of semispan commercial transport model with wing-mounted advanced ducted propeller operating in reverse thrust. [conducted in the Langley 14 by 22 foot subsonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Applin, Zachary T.; Jones, Kenneth M.; Gile, Brenda E.; Quinto, P. Frank

    1994-01-01

    A test was conducted in the Langley 14 by 22 Foot Subsonic Tunnel to determine the effect of the reverse-thrust flow field of a wing-mounted advanced ducted propeller on the aerodynamic characteristics of a semispan subsonic high-lift transport model. The advanced ducted propeller (ADP) model was mounted separately in position alongside the wing so that only the aerodynamic interference of the propeller and nacelle affected the aerodynamic performance of the transport model. Mach numbers ranged from 0.14 to 0.26; corresponding Reynolds numbers ranged from 2.2 to 3.9 x 10(exp 6). The reverse-thrust flow field of the ADP shielded a portion of the wing from the free-stream airflow and reduced both lift and drag. The reduction in lift and drag was a function of ADP rotational speed and free-stream velocity. Test results included ground effects data for the transport model and ADP configuration. The ground plane caused a beneficial increase in drag and an undesirable slight increase in lift. The ADP and transport model performance in ground effect was similar to performance trends observed for out of ground effect. The test results form a comprehensive data set that supports the application of the ADP engine and airplane concept on the next generation of advanced subsonic transports. Before this investigation, the engine application was predicted to have detrimental ground effect characteristics. Ground effect test measurements indicated no critical problems and were the first step in proving the viability of this engine and airplane configuration.

  19. Erlotinib in Treating Patients With Unresectable Liver, Bile Duct, or Gallbladder Cancer

    ClinicalTrials.gov

    2013-06-03

    Adult Primary Cholangiocellular Carcinoma; Adult Primary Hepatocellular Carcinoma; Advanced Adult Primary Liver Cancer; Cholangiocarcinoma of the Extrahepatic Bile Duct; Cholangiocarcinoma of the Gallbladder; Localized Unresectable Adult Primary Liver Cancer; Recurrent Adult Primary Liver Cancer; Recurrent Extrahepatic Bile Duct Cancer; Recurrent Gallbladder Cancer; Unresectable Extrahepatic Bile Duct Cancer; Unresectable Gallbladder Cancer

  20. Numerical computation of aerodynamics and heat transfer in a turbine cascade and a turn-around duct using advanced turbulence models

    NASA Astrophysics Data System (ADS)

    Lakshminarayana, B.; Luo, J.

    1993-07-01

    The objective of this research is to develop turbulence models to predict the flow and heat transfer fields dominated by the curvature effect such as those encountered in turbine cascades and turn-around ducts. A Navier-Stokes code has been developed using an explicit Runge-Kutta method with a two layer k-epsilon/ARSM (Algebraic Reynolds Stress Model), Chien's Low Reynolds Number (LRN) k-epsilon model and Coakley's LRN q-omega model. The near wall pressure strain correlation term was included in the ARSM. The formulation is applied to Favre-averaged N-S equations and no thin-layer approximations are made in either the mean flow or turbulence transport equations. Anisotropic scaling of artificial dissipation terms was used. Locally variable timestep was also used to improve convergence. Detailed comparisons were made between computations and data measured in a turbine cascade by Arts et al. at Von Karman Institute. The surface pressure distributions and wake profiles were predicted well by all the models. The blade heat transfer is predicted well by k-epsilon/ARSM model, as well as the k-epsilon model. It's found that the onset of boundary layer transition on both surfaces is highly dependent upon the level of local freestream turbulence intensity, which is strongly influenced by the streamline curvature. Detailed computation of the flow in the turn around duct has been carried out and validated against the data by Monson as well as Sandborn. The computed results at various streamwise locations both on the concave and convex sides are compared with flow and turbulence data including the separation zone on the inner well. The k-epsilon/ARSM model yielded relatively better results than the two-equation turbulence models. A detailed assessment of the turbulence models has been made with regard to their applicability to curved flows.

  1. Numerical computation of aerodynamics and heat transfer in a turbine cascade and a turn-around duct using advanced turbulence models

    NASA Technical Reports Server (NTRS)

    Lakshminarayana, B.; Luo, J.

    1993-01-01

    The objective of this research is to develop turbulence models to predict the flow and heat transfer fields dominated by the curvature effect such as those encountered in turbine cascades and turn-around ducts. A Navier-Stokes code has been developed using an explicit Runge-Kutta method with a two layer k-epsilon/ARSM (Algebraic Reynolds Stress Model), Chien's Low Reynolds Number (LRN) k-epsilon model and Coakley's LRN q-omega model. The near wall pressure strain correlation term was included in the ARSM. The formulation is applied to Favre-averaged N-S equations and no thin-layer approximations are made in either the mean flow or turbulence transport equations. Anisotropic scaling of artificial dissipation terms was used. Locally variable timestep was also used to improve convergence. Detailed comparisons were made between computations and data measured in a turbine cascade by Arts et al. at Von Karman Institute. The surface pressure distributions and wake profiles were predicted well by all the models. The blade heat transfer is predicted well by k-epsilon/ARSM model, as well as the k-epsilon model. It's found that the onset of boundary layer transition on both surfaces is highly dependent upon the level of local freestream turbulence intensity, which is strongly influenced by the streamline curvature. Detailed computation of the flow in the turn around duct has been carried out and validated against the data by Monson as well as Sandborn. The computed results at various streamwise locations both on the concave and convex sides are compared with flow and turbulence data including the separation zone on the inner well. The k-epsilon/ARSM model yielded relatively better results than the two-equation turbulence models. A detailed assessment of the turbulence models has been made with regard to their applicability to curved flows.

  2. Modern management of common bile duct stones.

    PubMed

    Buxbaum, James

    2013-04-01

    It is imperative for gastroenterologists to understand the different formations of bile duct stones and the various medical treatments available. To minimize the complications of endoscopic retrograde cholangiopancreatography (ERCP), it is critical to appropriately assess the risk of bile duct stones before intervention. Biliary endoscopists should be comfortable with the basic techniques of stone removal, including sphincterotomy, mechanical lithotripsy, and stent placement. It is important to be aware of advanced options, including laser and electrohydraulic stone fragmentation, and papillary dilatation for problematic cases. The timing and need for ERCP in those who require a cholecystectomy is also a consideration. PMID:23540960

  3. A case of cholecystohepatic duct with atrophic common hepatic duct

    PubMed Central

    Schofield, A; Hankins, J

    2003-01-01

    Background Cholecystohepatic ducts are rare congenital variants of the biliary tree. Case outline An 81-year-old woman presented with biliary colic and elevated liver function tests. An ERCP demonstrated a common bile duct stone and stricture of the common hepatic duct. An operative cholangiogram demonstrated an atrophic common hepatic duct and retrograde filling of the gallbladder through a large cholecystoheptic duct. The patient had a cholecystectomy and reconstructive cholecystohepatic duct jejunostomy. Discussion This case demonstrates a rare congenital anomaly where the gallbladder fills retrograde during an intraoperative cholangiogram despite clipping of the cystic duct. The major path of biliary drainage was through a large cholecystoheptic duct similar to a gallbladder interposition; however, the common hepatic duct was still present but atrophic. This anomaly has not been described previously. PMID:18332999

  4. Buried and Encapsulated Ducts, Jacksonville, Florida (Fact Sheet)

    SciTech Connect

    Not Available

    2013-11-01

    Ductwork installed in unconditioned attics can significantly increase the overall heating and cooling costs of residential buildings. In fact, estimated duct thermal losses for single-family residential buildings with ductwork installed in unconditioned attics range from 10% to 45%. In a study of three single-story houses in Florida, the Building America research team Consortium for Advanced Residential Buildings (CARB) investigated the strategy of using buried and/or encapsulated ducts (BED) to reduce duct thermal losses in existing homes. The BED strategy consists of burying ducts in loose-fill insulation and/or encapsulating them in closed cell polyurethane spray foam (ccSPF) insulation. There are three possible combinations of BED strategies: (1) buried ducts; (2) encapsulated ducts (with ccSPF); and (3) buried and encapsulated ducts. The best solution for each situation depends on the climate, age of the house, and the configuration of the HVAC system and attic. For new construction projects, the team recommends that ducts be both encapsulated and buried as the minimal planning and costs required for this will yield optimal energy savings. The encapsulated/buried duct strategy, which utilizes ccSPF to address condensation concerns, is an approach that was developed specifically for humid climates.

  5. Transcystic Approach to Laparoscopic Common Bile Duct Exploration

    PubMed Central

    Fei, Zhewei; Huang, Xia; Wang, Xiaojun

    2014-01-01

    Background and Objectives: One-stage laparoscopic management for common bile duct stones in patients with gallbladder stones has gained wide acceptance. We developed a novel technique using a transcystic approach for common bile duct exploration as an alternative to the existing procedures. Methods: From April 2010 to June 2012, 9 consecutive patients diagnosed with cholelithiasis and common bile duct stones were enrolled in this study. The main inclusion criteria included no upper abdominal surgical history and the presence of a stone measuring <5 mm. After the gallbladder was dissected free from the liver connections in a retrograde fashion, the fundus of the gallbladder was extracted via the port incision in the right epigastrium. The choledochoscope was inserted into the gallbladder through the small opening in the fundus of the gallbladder extracorporeally and was advanced toward the common bile duct via the cystic duct under the guidance of both laparoscopic imaging and endoscopic imaging. After stones were retrieved under direct choledochoscopic vision, a drainage tube was placed in the subhepatic space. Results: Of 9 patients, 7 had successful transcystic common bile duct stone clearance. A narrow cystic duct and the unfavorable anatomy of the junction of the cystic duct and common bile duct resulted in losing access to the common bile duct. No bile leakage, hemobilia, or pancreatitis occurred. Wound infection occurred in 2 patients. Transient epigastric colic pain occurred in 2 patients and was relieved by use of anisodamine. A transient increase in the amylase level was observed in 3 patients. Short-term follow-up did not show any recurrence of common bile duct stones. Conclusion: Our novel transcystic approach to laparoscopic common bile duct exploration is feasible and efficient. PMID:25516702

  6. Patent arterial duct.

    PubMed

    Forsey, Jonathan T; Elmasry, Ola A; Martin, Robin P

    2009-07-10

    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 pulmonary overcirculation

  7. Patent arterial duct

    PubMed Central

    Forsey, Jonathan T; Elmasry, Ola A; Martin, Robin P

    2009-01-01

    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 pulmonary overcirculation

  8. CORNICE DUCT SYSTEM

    SciTech Connect

    Wayne Place; Chuck Ladd; TC Howard

    2002-12-01

    SYNERGETICS, INC., is in the process of designing, developing, and testing an air handling duct system that integrates the air duct with the cornice trim of interior spaces. The device has the advantage that the normal thermal losses from ducts into unconditioned attics and crawl spaces can be totally eliminated by bringing the ducts internal to the conditioned space. The following report details work conducted in the second budget period to develop the Cornice Duct System into a viable product for use in a variety of residential or small commercial building settings. A full-scale prototype has been fabricated and tested in a laboratory test building. Based on the results of that testing, the prototype design as been refined, fabricated, installed, and extensively tested in a residential laboratory house. The testing indicates that the device gives substantially superior performance to a standard air distribution system in terms of energy performance and thermal comfort. A patent has been submitted, refined based on feedback from the patent office, and resubmitted. Additional refinements to the design will lead to additional claims being added to the patent in the near future. Designs are being finalized for a refined version that will be fabricated and tested in the same residential laboratory house. Work is expected to be complete on this project in April of 2003.

  9. Advanced turboprop testbed systems study

    NASA Technical Reports Server (NTRS)

    Goldsmith, I. M.

    1982-01-01

    The proof of concept, feasibility, and verification of the advanced prop fan and of the integrated advanced prop fan aircraft are established. The use of existing hardware is compatible with having a successfully expedited testbed ready for flight. A prop fan testbed aircraft is definitely feasible and necessary for verification of prop fan/prop fan aircraft integrity. The Allison T701 is most suitable as a propulsor and modification of existing engine and propeller controls are adequate for the testbed. The airframer is considered the logical overall systems integrator of the testbed program.

  10. [Iatrogenic bile duct injuries].

    PubMed

    Ruiz Gómez, Francisco; Ramia Ángel, José Manuel; García-Parreño Jofré, Jorge; Figueras, Joan

    2010-10-01

    Bile duct injuries can be caused by different reasons, with Iatrogenic Bile Duct Injuries (IBDI) being the most common factor. IBDI is a complex situation produced in apparently healthy patients and is associated with a high rate of morbidity and a low rate of mortality. A multidisciplinary approach between surgeons, radiologist and endoscopist offers the best chances for an initial diagnosis, therapeutic options, management and follow up of complications for the patient. The aim of this review is to describe the current medical literature with reference to IBDI, and discuss our therapeutic algorithm.

  11. Effectiveness of duct cleaning methods on newly installed duct surfaces.

    PubMed

    Holopainen, R; Asikainen, V; Tuomainen, M; Björkroth, M; Pasanen, P; Seppänen, O

    2003-09-01

    Two kinds of air duct cleaning methods, mechanical brushing with different brushes and compressed air cleaning, were compared in the laboratory and in newly built buildings. The ducts were contaminated either with test dust or with dust originated from a construction site. The amount of dust on the duct surface was measured with the vacuum test method and estimated visually before and after the cleaning. In addition, the cleaning times of the different techniques were compared and the amount of residual oil in the ducts was measured in the laboratory test. The brushing methods were more efficient in metal ducts, and compressed air cleaning was more efficient in plastic ducts. After the duct cleaning the mean amount of residual dust on the surface of the ducts was ducts contaminated at construction site and ducts cleaned in the laboratory or in the building site, respectively. The oil residues and the dust stuck onto the oil were difficult to scrape off and remove, and none of the cleaning methods were capable of cleaning the oily duct surfaces efficiently enough. Thus new installations should consist only of oil-free ducts.

  12. Development of a 32 Inch Diameter Levitated Ducted Fan Conceptual Design

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Gallo, Christopher a.; Solano, Paul A.; Thompson, William K.; Vrnak, Daniel R.

    2006-01-01

    The NASA John H. Glenn Research Center has developed a revolutionary 32 in. diameter Levitated Ducted Fan (LDF) conceptual design. The objective of this work is to develop a viable non-contact propulsion system utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels, and mitigate many of the concerns and limitations encountered in conventional aircraft propulsors. The physical layout consists of a ducted fan drum rotor with blades attached at the outer diameter and supported by a stress tuner ring at the inner diameter. The rotor is contained within a stator. This concept exploits the unique physical dimensions and large available surface area to optimize a custom, integrated, electromagnetic system that provides both the levitation and propulsion functions. The rotor is driven by modulated electromagnetic fields between the rotor and the stator. When set in motion, the time varying magnetic fields interact with passive coils in the stator assembly to produce repulsive forces between the stator and the rotor providing magnetic suspension. LDF can provide significant improvements in aviation efficiency, reliability, and safety, and has potential application in ultra-efficient motors, computers, and space power systems.

  13. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    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.

  14. Cornice Duct System

    SciTech Connect

    Wayne Place; Chuck Ladd

    2004-10-29

    SYNERGETICS, INC., has designed, developed, and tested an air handling duct system that integrates the air duct with the cornice trim of interior spaces. The device has the advantage that the normal thermal losses from ducts into unconditioned attics and crawl spaces can be totally eliminated by bringing the ducts internal to the conditioned space. The following report details work conducted in the second budget period to develop the Cornice Duct System into a viable product for use in a variety of residential or small commercial building settings. A full-scale prototype has been fabricated and tested in a laboratory test building at the Daylighting Facility at North Carolina State University., Based on the results of that testing, the prototype design as been refined, fabricated, installed, and extensively tested in a residential laboratory house. The testing indicates that the device gives substantially superior performance to a standard air distribution system in terms of energy performance and thermal comfort. Patent Number US 6,511,373 B2 has been granted on the version of the device installed and tested in the laboratory house. (A copy of that patent is attached.) Refinements to the device have been carried through two additional design iterations, with a particular focus on reducing installation time and cost and refining the air control system. These new designs have been fabricated and tested and show substantial promise. Based on these design and testing iterations, a final design is proposed as part of this document. That final design is the basis for a continuation in part currently being filed with the U.5, Patent office.

  15. Remnant cystic duct adenocarcinoma presenting as gastric outlet obstruction

    PubMed Central

    Lo, Samuel Tsoon Wuan; Cheng, Yue; Cheung, Frances; Tang, Chung Ngai

    2016-01-01

    Only a few case reports of remnant cystic duct carcinoma exist. The presented case of remnant cystic duct carcinoma with invasion to pylorus and bulbus of duodenum leading to gastric outlet obstruction was the first of its kind. We reviewed all cases of remnant cystic duct carcinoma that we found in the literature and summarized its definition, presentation, extent of invasion and clinical outcome after operation. The diagnosis can be difficult due to the rarity of disease, locally advanced nature of disease and distorted postoperative anatomy. A high index of suspicion can increase the likelihood of a preoperative diagnosis. PMID:27154747

  16. BETTER DUCT SYSTEMS FOR HOME HEATING AND COOLING.

    SciTech Connect

    ANDREWS,J.

    2001-01-01

    This is a series of six guides intended to provide a working knowledge of residential heating and cooling duct systems, an understanding of the major issues concerning efficiency, comfort, health, and safety, and practical tips on installation and repair of duct systems. These guides are intended for use by contractors, system designers, advanced technicians, and other HVAC professionals. The first two guides are also intended to be accessible to the general reader.

  17. Mediastinal thoracic duct cyst.

    PubMed Central

    Gowar, F J

    1978-01-01

    A case of mediastinal thoracic duct cyst is described; it is believed to be the first to be reported in Britain. Five surgically treated cases have been reported but in none was the diagnosis made before operation. Symptoms are caused by pressure of the cyst on the trachea and oesophagus and my be aggravted by eating a fatty meal. Differential diagnosis from other mediastinal tumours, especially bronchogenic cyst and neurofibroma, could perhaps be established before operation by lymphangiography. Images PMID:746509

  18. Rhinosporidiosis of parotid duct.

    PubMed

    Sivapathasundharam, B; Saraswathi, T R; Manjunath, K; Sriram, G

    2009-01-01

    Rhinosporidiosis is a benign chronic granulomatous infection caused by Rhinosporidium seeberi. Rhinosporidiosis is endemic in south Asia, notably in southern India and Sri Lanka. Majority of the cases have been reported to occur in upper respiratory sites, notably anterior nares, nasal cavity, nasopharynx, larynx and soft palate. Only two rare cases of involvement of parotid duct, have been reported in literature. Hence, this case will probably be the third to be reported.

  19. Primary salivary duct carcinoma arising from the Stensen duct.

    PubMed

    Noda, Kenji; Hirano, Takashi; Okamoto, Tomoyo; Suzuki, Masashi

    2016-09-01

    This report describes a salivary duct carcinoma (SDC) arising from the extraglandular portion of the Stensen duct. The patient was a 56-year-old man who presented with a palpable, elastic, hard mass without tenderness in the right cheek. Computed tomography revealed a tumor of the extraglandular portion of the Stensen duct. Supraomohyoid right neck dissection and total right parotidectomy were performed, and the histologic diagnosis was SDC of the Stensen duct. Postoperatively, the patient received no additional treatment. Neither recurrence nor metastasis was observed during 4 years of follow-up examination. SDC of the Stensen duct is extremely rare. To our knowledge, there is no report that describes primary SDC arising from that location. We also believe this is the first report that describes the clinical course of primary SDC arising from a Stensen duct. PMID:27657321

  20. Generation of Higher Order Modes in a Rectangular Duct

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Cabell, Randolph H.; Brown, Donald E.

    2004-01-01

    Advanced noise control methodologies to reduce sound emission from aircraft engines take advantage of the modal structure of the noise in the duct. This noise is caused by the interaction of rotor wakes with downstream obstructions such as exit guide vanes. Mode synthesis has been accomplished in circular ducts and current active noise control work has made use of this capability to cancel fan noise. The goal of the current effort is to examine the fundamental process of higher order mode propagation through an acoustically treated, curved duct. The duct cross-section is rectangular to permit greater flexibility in representation of a range of duct curvatures. The work presented is the development of a feedforward control system to generate a user-specified modal pattern in the duct. The multiple-error, filtered-x LMS algorithm is used to determine the magnitude and phase of signal input to the loudspeakers to produce a desired modal pattern at a set of error microphones. Implementation issues, including loudspeaker placement and error microphone placement, are discussed. Preliminary results from a 9-3/8 inch by 21 inch duct, using 12 loudspeakers and 24 microphones, are presented. These results demonstrate the ability of the control system to generate a user-specified mode while suppressing undesired modes.

  1. Noise reduction of spiral ducts.

    PubMed

    Lapka, Wojciech; Cempel, Czesław

    2007-01-01

    The paper presents noise reduction (NR) of spiral ducts as a result of computational modeling of acoustic wave propagation. Three-dimensional models were created with the finite element method in COMSOL Multiphysics version 3.3. Nine models of spiral ducts with 1-9 spiral leads were considered. Time-harmonic analysis was used to predict NR, which was shown in spectral and interval frequency bands. Spiral duct performance can be seen as a comparison of NR before and after a change from a circular to a spiral duct.

  2. Technology Solutions Case Study: Buried and Encapsulated Ducts, Jacksonville, Florida

    SciTech Connect

    2013-11-01

    Ductwork installed in unconditioned attics can significantly increase the overall heating and cooling costs of residential buildings. In fact, estimated duct thermal losses for single-family residential buildings with ductwork installed in unconditioned attics range from 10% to 45%. In a study of three single-story houses in Florida, the Building America research team Consortium for Advanced Residential Buildings (CARB) investigated the strategy of using buried and/or encapsulated ducts (BED) to reduce duct thermal losses in existing homes. The BED strategy consists of burying ducts in loose-fill insulation and/or encapsulating them in closed cell polyurethane spray foam (ccSPF) insulation; specifically for use in humid climates.

  3. Measure Guideline: Buried and/or Encapsulated Ducts

    SciTech Connect

    Shapiro, C.; Zoeller, W.; Mantha, P.

    2013-08-01

    Buried and/or encapsulated ducts (BEDs) are a class of advanced, energy-efficiency strategies intended to address the significant ductwork thermal losses associated with ducts installed in unconditioned attics. BEDs are ducts installed in unconditioned attics that are covered in loose-fill insulation and/or encapsulated in closed cell polyurethane spray foam insulation. This Measure Guideline covers the technical aspects of BEDs as well as the advantages, disadvantages, and risks of BEDs compared to other alternative strategies. This guideline also provides detailed guidance on installation of BEDs strategies in new and existing homes through step-by-step installation procedures. Some of the procedures presented here, however, require specialized equipment or expertise. In addition, some alterations to duct systems may require a specialized license.

  4. Intrahepatic Transposition of Bile Ducts

    PubMed Central

    Delić, Jasmin; Savković, Admedina; Isaković, Eldar; Marković, Sergije; Bajtarevic, Alma; Denjalić, Amir

    2012-01-01

    Objective. To describe the intrahepatic bile duct transposition (anatomical variation occurring in intrahepatic ducts) and to determine the frequency of this variation. Material and Methods. The researches were performed randomly on 100 livers of adults, both sexes. Main research methods were anatomical macrodissection. As a criterion for determination of variations in some parts of bile tree, we used the classification of Segmentatio hepatis according to Couinaud (1957) according to Terminologia Anatomica, Thieme Stuugart: Federative Committee on Anatomical Terminology, 1988. Results. Intrahepatic transposition of bile ducts was found in two cases (2%), out of total examined cases (100): right-left transposition (right segmental bile duct, originating from the segment VIII, joins the left liver duct-ductus hepaticus sinister) and left-right intrahepatic transposition (left segmental bile duct originating from the segment IV ends in right liver duct-ductus hepaticus dexter). Conclusion. Safety and success in liver transplantation to great extent depends on knowledge of anatomy and some common embryological anomalies in bile tree. Variations in bile tree were found in 24–43% of cases, out of which 1–22% are the variations of intrahepatic bile ducts. Therefore, good knowledge on ductal anatomy enables good planning, safe performance of therapeutic and operative procedures, and decreases the risk of intraoperative and postoperative complications. PMID:22550601

  5. Measure Guideline: Buried and/or Encapsulated Ducts

    SciTech Connect

    Shapiro, C.; Zoeller, W.; Mantha, P.

    2013-08-01

    Buried and/or encapsulated ducts (BEDs) are a class of advanced, energy-efficiency strategies intended to address the significant ductwork thermal losses associated with ducts installed in unconditioned attics. BEDs are ducts installed in unconditioned attics that are covered in loose-fill insulation and/or encapsulated in closed cell polyurethane spray foam insulation. This Measure Guideline covers the technical aspects of BEDs as well as the advantages, disadvantages, and risks of BEDs compared to other alternative strategies. This guideline also provides detailed guidance on installation of BEDs strategies in new and existing homes through step-by-step installation procedures. This Building America Measure Guideline synthesizes previously published research on BEDs and provides practical information to builders, contractors, homeowners, policy analysts, building professions, and building scientists. Some of the procedures presented here, however, require specialized equipment or expertise. In addition, some alterations to duct systems may require a specialized license. Persons implementing duct system improvements should not go beyond their expertise or qualifications. This guideline provides valuable information for a building industry that has struggled to address ductwork thermal losses in new and existing homes. As building codes strengthen requirements for duct air sealing and insulation, flexibility is needed to address energy efficiency goals. While ductwork in conditioned spaces has been promoted as the panacea for addressing ductwork thermal losses, BEDs installations approach - and sometimes exceed - the performance of ductwork in conditioned spaces.

  6. PMR Graphite Engine Duct Development

    NASA Technical Reports Server (NTRS)

    Stotler, C. L.; Yokel, S. A.

    1989-01-01

    The objective was to demonstrate the cost and weight advantages that could be obtained by utilizing the graphite/PMR15 material system to replace titanium in selected turbofan engine applications. The first component to be selected as a basis for evaluation was the outer bypass duct of the General Electric F404 engine. The operating environment of this duct was defined and then an extensive mechanical and physical property test program was conducted using material made by processing techniques which were also established by this program. Based on these properties, design concepts to fabricate a composite version of the duct were established and two complete ducts fabricated. One of these ducts was proof pressure tested and then run successfully on a factory test engine for over 1900 hours. The second duct was static tested to 210 percent design limit load without failure. An improved design was then developed which utilized integral composite end flanges. A complete duct was fabricated and successfully proof pressure tested. The net results of this effort showed that a composite version of the outer duct would be 14 percent lighter and 30 percent less expensive that the titanium duct. The other type of structure chosen for investigation was the F404 fan stator assembly, including the fan stator vanes. It was concluded that it was feasible to utilize composite materials for this type structure but that the requirements imposed by replacing an existing metal design resulted in an inefficient composite design. It was concluded that if composites were to be effectively used in this type structure, the design must be tailored for composite application from the outset.

  7. Basic tips for duct design

    SciTech Connect

    Evans, R.A.; Tsal, R.J.

    1996-07-01

    During the last few years, ASHRAE Journal and other trade publications have presented lucid descriptions of the basic physics of airflow in ductwork, pressure drop and methods of sizing and optimization (Brooks 1995, Tsal et al. 1988a, Williams 1995). What is missing is a practical means for numerically modeling HVAC duct systems. This article is centered on the performance, economics and modeling of duct systems. Specific subjects examined include duct shape, fitting performance, leakage and appropriate oversizing. Computer modeling is discussed to provide a better grasp as to how it can be used as a practical design tool.

  8. Articulated transition duct in turbomachine

    SciTech Connect

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

    2014-04-29

    Turbine systems are provided. 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 and a downstream portion. The upstream portion extends from the inlet between an inlet end and an aft end. The downstream portion extends from the outlet between an outlet end and a head end. The turbine system further includes a joint coupling the aft end of the upstream portion and the head end of the downstream portion together. The joint is configured to allow movement of the upstream portion and the downstream portion relative to each other about or along at least one axis.

  9. Wave reflections from duct terminations.

    PubMed

    Selamet, A; Ji, Z L; Kach, R A

    2001-04-01

    The reflection coefficients and inertial end corrections of several duct terminations, including finite length duct extensions perpendicular to an infinite wall, as well as at a number of angles, curved interface surfaces, and annular cavities, are determined and analyzed in the absence of flow by employing the boundary element method. Predictions for the classical unflanged and flanged circular ducts show good agreement with analytical and computational results available in the literature. The predictions for curved interface surfaces (bellmouth or horn) are also consistent with the available experimental data. In view of its high reflection coefficient, the duct termination with an annular cavity may be suggested for the suppression of noise radiation in a specific frequency band or for an effective wave reflection from the termination. PMID:11325101

  10. Flexible Borescope For Inspecting Ducts

    NASA Technical Reports Server (NTRS)

    Shinozaki, Keith; Armstrong, Mike P.; Urquidi, Ron

    1995-01-01

    Borescope and associated equipment developed specifically for use in optical inspection of inside of flexible joints in rocket-engine fuel duct. Apparatus includes assembly, characterized as "mouse/canoe," at sensing end of 10-ft borescope cable. Borescope tip rides in mouse/canoe. The mouse/canoe made laterally compressible, to facilitate movement past constrictions and provides fixed distance from inspection point permitting accurate description in duct inspected.

  11. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    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.

  12. Laminar flow in twisted ducts

    NASA Astrophysics Data System (ADS)

    Kheshgi, Haroon S.

    1993-11-01

    Fully developed flow of an incompressible Newtonian fluid through a duct in which the orientation of the cross section is twisted about an axis parallel to an imposed pressure gradient is analyzed here with the aid of the penalty/Galerkin/finite element method. When the axis of twist is located within the duct, flow approaches limits at low and high torsion, the spatial frequency τ by which the duct is twisted. For small torsion, flow is nearly rectilinear and solutions approach previous asymptotic results for an elliptical cross section. For large torsion, flow exhibits an internal layer structure: a rotating circular-cylinder core with a nearly parabolic axial velocity profile, an internal layer of thickness τ-1 along the perimeter of the largest circular cylinder that can be inscribed in the duct, and nearly quiescent flow outside of the circular cylinder. The maximum rate of swirl in the core of a square duct is found to be at moderate torsion. The primary effect of inertia is an increase in pressure with distance from the axis, due to centrifugal acceleration. When the duct is offset from the axis of twist, inertia leads to one, two, or three primary vortices without apparent bifurcation of steady states, although stability of steady flows is lost beyond detected Hopf points.

  13. Bile duct invasion can be an independent prognostic factor in early stage hepatocellular carcinoma

    PubMed Central

    Jang, Ye-Rang; Kim, Hyeyoung; Lee, Jeong-Moo; Yi, Nam-Joon; Suh, Kyung-Suk

    2015-01-01

    Backgrounds/Aims In hepatocellular carcinoma (HCC), bile duct invasion occurs far more rarely than vascular invasion and is not well characterized. In addition, the pathologic finding of bile duct invasion is not considered an independent prognostic factor for HCC following surgery. In this study, we determined the characteristics of HCC with bile duct invasion, and assessed the clinical significance of bile duct invasion. Methods We retrospectively reviewed the medical records of 363 patients who underwent hepatic resection for HCC at Seoul National University Hospital (SNUH) from January 2009 to December 2011. Preoperative, operative, and pathological data were collected. The risk factors for recurrence and survival were analyzed. Subsequently, the patients were divided into 2 groups according to disease stage (American Joint Committee on Cancer/International Union Against Cancer 7th edition): early stage (T1 and 2) and advanced stage (T3 and 4) group; and risk factors in the sub-groups were analyzed. Results Among 363 patients, 13 showed bile duct invasion on pathology. Patients with bile duct invasion had higher preoperative total bilirubin levels, greater microvascular invasion, and a higher death rate than those without bile duct invasion. In multivariate analysis, bile duct invasion was not an independent prognostic factor for survival for the entire cohort, but, was an independent prognostic factor for early stage. Conclusions Bile duct invasion accompanied microvascular invasion in most cases, and could be used as an independent prognostic factor for survival especially in early stage HCC (T1 and T2). PMID:26693236

  14. An isolated nasolacrimal duct osteoma.

    PubMed

    Kim, Joo Yeon; Kwon, Jae Hwan

    2013-07-01

    Osteomas of the nose and paranasal sinus are common benign tumors that can extend to surrounding structures and result in orbital or intracranial involvement. Presenting symptoms include facial pain, headache, cerebral symptoms, ocular symptoms, and so on, depending on the location and size of the tumor. They commonly occur within the frontal, ethmoid, maxillary, and sphenoid sinuses; however, there are rare cases of reported osteomas in the nasal cavity, turbinate, or orbit. Our case report describes a patient with nasolacrimal duct osteoma who presented with ipsilateral ocular pain, epiphora, and medial canthal swelling. We performed intranasal dacryocystorhinostomy using a nasal endoscope and removed the lacrimal duct osteoma. This report describes symptoms and management of an isolated nasolacrimal duct stone with a review of the literature.

  15. General Information about Extrahepatic Bile Duct Cancer

    MedlinePlus

    ... Bile Duct Cancer Treatment (PDQ®)–Patient Version General Information About Bile Duct Cancer Go to Health Professional ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  16. Vitellointestinal Duct Anomalies in Infancy

    PubMed Central

    Kadian, Yogender Singh; Verma, Anjali; Rattan, Kamal Nain; Kajal, Pardeep

    2016-01-01

    Background: Vitellointestinal duct (VID) or omphalomesenteric duct anomalies are secondary to the persistence of the embryonic vitelline duct, which normally obliterates by weeks 5–9 of intrauterine life. Methods: This is a retrospective analysis of a total of 16 patients of symptomatic remnants of vitellointestinal duct from period of Jan 2009 to May 2013. Results: Male to female ratio (M:F) was 4.3:1 and mean age of presentation was 2 months and their mode of presentation was: patent VID in 9 (56.25%) patients, umbilical cyst in 2(12.25%), umbilical granuloma in 2 (12.25%), and Meckel diverticulum as content of hernia sac in obstructed umbilical hernia in 1 (6.25%) patient. Two patients with umbilical fistula had severe electrolyte disturbance and died without surgical intervention. Conclusion: Persistent VID may have varied presentations in infancy. High output umbilical fistula and excessive bowel prolapse demand urgent surgical intervention to avoid morbidity and mortality. PMID:27433448

  17. Arc Reflector For Welding Ducts

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.

    1990-01-01

    Arc-light reflector for through-the-torch welding vision system designed expressly for use in welding ducts of small diameter. Cylindrical reflector positioned to reflect light diffusely from welding arc onto nearby surface of workpiece for most advantageous viewing along axis of welding torch.

  18. Design and performance of duct acoustic treatment

    NASA Technical Reports Server (NTRS)

    Motsinger, R. E.; Kraft, R. E.

    1991-01-01

    The procedure for designing acoustic treatment panels used to line the walls of aircraft engine ducts and for estimating the resulting suppression of turbofan engine duct noise is discussed. This procedure is intended to be used for estimating noise suppression of existing designs or for designing new acoustic treatment panels and duct configurations to achieve desired suppression levels.

  19. Extrahepatic Bile Duct Obstruction and Erosive Disruption by Cavitating Porta Hepatis Nodal Metastasis, Treated by Uncovered Wallstent

    SciTech Connect

    Trambert, Jonathan J. Frost, Andrei; Malasky, Charlotte

    2004-08-15

    A 45-year-old woman with advanced gastric carcinoma presented with obstructive jaundice. Percutaneous transhepatic cholangiography (PTC) revealed erosive disruption of the extrahepatic bile ducts by a cavitating metastasis in the porta hepatis, as well as a biliary-duodenal fistula. External-internal biliary drainage via the fistula was plagued by recurrent drain occlusion by necrotic debris. This was ultimately alleviated by successful catheterization of the distal common bile duct (CBD) through the cavity, and linking the common hepatic duct (CHD) and CBD with a Wallstent, across the cavity. This succeeded in improving internal biliary drainage and isolating the exfoliating debris of the cavity from the bile ducts.

  20. Analytical screening of low emissions, high performance duct burners for supersonic cruise aircraft engines

    NASA Technical Reports Server (NTRS)

    Lohmann, R. A.; Riecke, G. T.

    1977-01-01

    An analytical screening study was conducted to identify duct burner concepts capable of providing low emissions and high performance in advanced supersonic engines. Duct burner configurations ranging from current augmenter technology to advanced concepts such as premix-prevaporized burners were defined. Aerothermal and mechanical design studies provided the basis for screening these configurations using the criteria of emissions, performance, engine compatibility, cost, weight and relative risk. Technology levels derived from recently defined experimental low emissions main burners are required to achieve both low emissions and high performance goals. A configuration based on the Vorbix (Vortex burning and mixing) combustor concept was analytically determined to meet the performance goals and is consistent with the fan duct envelope of a variable cycle engine. The duct burner configuration has a moderate risk level compatible with the schedule of anticipated experimental programs.

  1. Coexistence of multiple omphalomesenteric duct anomalies.

    PubMed

    Ioannidis, Orestis; Paraskevas, George; Kakoutis, Emmanouil; Kotronis, Anastasios; Papadimitriou, Nikos; Chatzopoulos, Stavros; Makrantonakis, Apostolos

    2012-08-01

    The omphalomesenteric duct is an embryonic structure which connects the yolk sac to the midgut. The omphalomesenteric duct attenuates between the 5th and 9th week of gestation. Failure of the omphalomesenteric duct involution, either partial or complete, results in various omphalomesenteric duct remnants including Meckel's diverticulum, patent vitelline duct, fibrous band, sinus tract, umbilical polyp and cyst. Omphalomesenteric duct remnants are present in 2% of the population but related diseases have seldom been reported in adults. The simultaneous presence of sinus tract, omphalomesenteric cyst, fibrous ligament and Meckel's diverticulum has, according to authors' knowledge, never been reported. We present a case of a 23 years old male with persisting umbilical discharge for 2 years in whom there was coexistence of the above mentioned anomalies of the omphalomesenteric duct.

  2. Tear-ducts in wine

    NASA Astrophysics Data System (ADS)

    Bush, John W. M.

    1999-11-01

    We examine the radial spoke pattern evident in the meniscus region in glasses of strong alcoholic beverages exhibiting the `tears-in-wine' phenomenon. We demonstrate that the pattern results from ridge-like elevations of the free surface which are supported by evaporatively-driven Marangoni convection in the meniscus region. Vortices associated with the convective motions are aligned in the radial direction by the surface tension gradient responsible for the generation of tears. The radial flow is focussed into the ridges, which thus serve as the principal conduits of fluid for the tears; consequently, we refer to the ridges as `tear-ducts'. The phenomenon is examined experimentally, and a numerical model of evaporatively-driven Marangoni convection is developed which reproduces the salient features of the tear-duct phenomenon.

  3. HAARP-Induced Ionospheric Ducts

    SciTech Connect

    Milikh, Gennady; Vartanyan, Aram

    2011-01-04

    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.

  4. Ducted propeller design and analysis

    SciTech Connect

    Weir, R.J.

    1987-10-01

    The theory and implementation of the design of a ducted propeller blade are presented and discussed. Straightener (anti-torque) vane design is also discussed. Comparisons are made to an existing propeller design and the results and performance of two example propeller blades are given. The inflow velocity at the propeller plane is given special attention and two dimensionless parameters independent of RPM are discussed. Errors in off-design performance are also investigated. 11 refs., 26 figs.

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

    PubMed Central

    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

  6. Modeling particle loss in ventilation ducts

    SciTech Connect

    Sippola, Mark R.; Nazaroff, William W.

    2003-04-01

    Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 {micro}m are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.

  7. Ramjet bypass duct and preburner configuration

    NASA Technical Reports Server (NTRS)

    Orlando, Robert J. (Inventor)

    1994-01-01

    A combined turbofan and ramjet aircraft engine includes a forward bypass duct which allows the engine to operate more efficiently during the turbofan mode of operation. By mounting a ramjet preburner in the forward duct and isolating this duct from the turbofan bypass air, a transition from turbofan operation to ramjet operation can take place at lower flight Mach numbers without incurring pressure losses or blockage in the turbofan bypass air.

  8. 14 CFR 25.1103 - Induction system ducts and air duct systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... units must be fireproof within the auxiliary power unit fire zone. (c) Each duct connected to components... induction system duct must be fireproof for a sufficient distance upstream of the auxiliary power...

  9. 14 CFR 25.1103 - Induction system ducts and air duct systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... units must be fireproof within the auxiliary power unit fire zone. (c) Each duct connected to components... induction system duct must be fireproof for a sufficient distance upstream of the auxiliary power...

  10. 14 CFR 25.1103 - Induction system ducts and air duct systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... units must be fireproof within the auxiliary power unit fire zone. (c) Each duct connected to components... induction system duct must be fireproof for a sufficient distance upstream of the auxiliary power...

  11. 14 CFR 25.1103 - Induction system ducts and air duct systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... units must be fireproof within the auxiliary power unit fire zone. (c) Each duct connected to components... induction system duct must be fireproof for a sufficient distance upstream of the auxiliary power...

  12. 14 CFR 25.1103 - Induction system ducts and air duct systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... units must be fireproof within the auxiliary power unit fire zone. (c) Each duct connected to components... induction system duct must be fireproof for a sufficient distance upstream of the auxiliary power...

  13. Circumportal pancreas with retroportal main pancreatic duct.

    PubMed

    Hashimoto, Yasushi; Ross, Andrew S; Traverso, L William

    2009-08-01

    There have been 6 cases of circumportal pancreas reported, and 2 of them had the main pancreatic duct in a retroportal dorsal portion. This extremely uncommon anomaly is asymptomatic and therefore incidentally discovered. For the surgeon, it is important to discover this during pancreatic resection so the pancreatic duct can be closed and fistula is avoided. We describe the third case where a circumportal pancreas had its main pancreatic duct passing under the portal vein. The duct was identified and ligated. A fistula did not occur.

  14. Generator stator core vent duct spacer posts

    DOEpatents

    Griffith, John Wesley; Tong, Wei

    2003-06-24

    Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

  15. Lightweight Forms for Epoxy/Aramid Ducts

    NASA Technical Reports Server (NTRS)

    Mix, E. W.; Anderson, A. N.; Bedford, Donald L., Sr.

    1986-01-01

    Aluminum mandrels easy to remove. Lightweight aluminum mandrel for shaping epoxy/aramid ducts simplifies and speeds production. In new process, glass-reinforced epoxy/aramid cloth wrapped on aluminum mandrel. Stainless-steel flanges and other hardware fitted on duct and held by simple tooling. Entire assembly placed in oven to cure epoxy. After curing, assembly placed in alkaline bath dissolves aluminum mandrel in about 4 hours. Epoxy/aramid shell ready for use as duct. Aluminum mandrel used to make ducts of various inside diameters up to 6 in. Standard aluminum forms used. Conventional tube-bending equipment produces requisite curves in mandrels.

  16. Flow through rotating rectangular ducts

    NASA Astrophysics Data System (ADS)

    Nandakumar, K.; Raszillier, H.; Durst, F.

    1991-05-01

    The bifurcation structure of two-dimensional, pressure-driven flows through a rectangular duct that is rotating about an axis perpendicular to its own is examined at a fixed Ekman number (Ek=ν/b2Ω) of 0.01. The solution structure for flow through a square duct (aspect ratio γ=1) is determined for Rossby numbers (Ro=U/bΩ) in the range of 0-5 using a computational scheme based on the arclength continuation method. The structure is much more complicated than reported earlier by Kheshgi and Scriven [Phys. Fluids 28, 2968 (1985)]. The primary branch with two limit points in Rossby number and a hysteresis behavior between the two- and four-cell flow structure that was computed by Kheshgi and Scriven is confirmed. An additional symmetric solution branch, which is disconnected from the primary branch (or rather connected via an asymmetric solution branch), is found. This has a two-cell flow structure at one end, a four-cell flow structure at the other and three limit points are located on the path. Two asymmetric solution branches emanating from symmetry breaking bifurcation points are also found for a square duct. Thus even within a Rossby number range of 0-5 a much richer solutions structure is found with up to five solutions at Ro=5. An eigenvalue calculation indicates that all two-dimensional solutions develop some form of unstable mode by the time Ro is increased to 5.0. In particular, the four-cell solution becomes unstable to asymmetric perturbations as found in a related problem of flow through a curved duct. The paths of the singular points are tracked with respect to variation in the aspect ratio using the fold following algorithm. A transcritical point is found at an aspect ratio of 0.815 and below which the four-cell solution is no longer on the primary branch. When the channel cross section is tilted even slightly (1°) with respect to the axis of rotation, the bifurcation points unfold and the two-cell solution evolves smoothly as Rossby number is

  17. Locating and Quantifying Broadband Fan Sources Using In-Duct Microphones

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    In-duct beamforming techniques have been developed for locating broadband noise sources on a low-speed fan and quantifying the acoustic power in the inlet and aft fan ducts. The NASA Glenn Research Center's Advanced Noise Control Fan was used as a test bed. Several of the blades were modified to provide a broadband source to evaluate the efficacy of the in-duct beamforming technique. Phased arrays consisting of rings and line arrays of microphones were employed. For the imaging, the data were mathematically resampled in the frame of reference of the rotating fan. For both the imaging and power measurement steps, array steering vectors were computed using annular duct modal expansions, selected subsets of the cross spectral matrix elements were used, and the DAMAS and CLEAN-SC deconvolution algorithms were applied.

  18. 14 CFR 29.1103 - Induction systems ducts and air duct systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-extinguishing system is required must be at least— (1) Fireproof, if it passes through any firewall; or (2) Fire resistant, for other ducts, except that ducts for auxiliary power units must be fireproof within the auxiliary power unit fire zone. (e) Each auxiliary power unit induction system duct must be fireproof for...

  19. 14 CFR 29.1103 - Induction systems ducts and air duct systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...-extinguishing system is required must be at least— (1) Fireproof, if it passes through any firewall; or (2) Fire resistant, for other ducts, except that ducts for auxiliary power units must be fireproof within the auxiliary power unit fire zone. (e) Each auxiliary power unit induction system duct must be fireproof for...

  20. 14 CFR 29.1103 - Induction systems ducts and air duct systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...-extinguishing system is required must be at least— (1) Fireproof, if it passes through any firewall; or (2) Fire resistant, for other ducts, except that ducts for auxiliary power units must be fireproof within the auxiliary power unit fire zone. (e) Each auxiliary power unit induction system duct must be fireproof for...

  1. 14 CFR 29.1103 - Induction systems ducts and air duct systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...-extinguishing system is required must be at least— (1) Fireproof, if it passes through any firewall; or (2) Fire resistant, for other ducts, except that ducts for auxiliary power units must be fireproof within the auxiliary power unit fire zone. (e) Each auxiliary power unit induction system duct must be fireproof for...

  2. 14 CFR 29.1103 - Induction systems ducts and air duct systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...-extinguishing system is required must be at least— (1) Fireproof, if it passes through any firewall; or (2) Fire resistant, for other ducts, except that ducts for auxiliary power units must be fireproof within the auxiliary power unit fire zone. (e) Each auxiliary power unit induction system duct must be fireproof for...

  3. Optimization of the mechanical performance of a two-duct semicircular duct system--part 1: dynamics and duct dimensions.

    PubMed

    Muller, M; Verhagen, J H G

    2002-06-21

    The classical representation of the semicircular duct system consists of three separate duct circuits. The ducts are, however, in reality, hydrodynamically interconnected. Muller & Verhagen (1988a,b) derived equations for the mechanical behaviour of an interconnected system with three ducts (anterior, posterior and horizontal). An analytical solution of these equations would, however, be too complex to provide surveyable formulae. A system of two interconnected ducts avoids this complexity whilst keeping the essentials of the coupling of ducts intact. The solution of the equation of motion leads to expressions for time constants and maximal endolymph excursions which are functions of morphological parameters, viz. the ratios of radii (gamma) and lengths (lambda) of the common vestibular part (crus commune or utriculus) and the ducts. The system possesses two short time constants which are shown to have similar values. The maximum endolymph displacements in the two ducts after a steplike stimulus are the products of the respective initial velocities and combinations of time constants. The initial velocities depend strongly on the position of the labyrinth with respect to the excitating rotation vector. Measured data of gamma and lambda are compared with the theoretical results. For gamma, excellent agreement was found. lambda is treated elsewhere. PMID:12151258

  4. Radiated noise of ducted fans

    NASA Technical Reports Server (NTRS)

    Eversman, Walter

    1992-01-01

    The differences in the radiated acoustic fields of ducted and unducted propellers of the same thrust operating under similar conditions are investigated. An FEM model is created for the generation, propagation, and radiation of steady, rotor alone noise and exit guide vane interaction noise of a ducted fan. For a specified number of blades, angular mode harmonic, and rotor angular velocity, the acoustic field is described in a cylindrical coordinate system reduced to only the axial and radial directions. It is found that, contrary to the usual understanding of the Tyler and Sofrin (1962) result, supersonic tip speed rotor noise can be cut off if the tip Mach number is only slightly in excess of unity and if the number of blades is relatively small. If there are many blades, the fundamental angular mode number is large, and the Tyler and Sofrin result for thin annuli becomes more relevant. Shrouding of subsonic tip speed propellers is a very effective means of controlling rotor alone noise.

  5. Radiated noise of ducted fans

    NASA Astrophysics Data System (ADS)

    Eversman, Walter

    The differences in the radiated acoustic fields of ducted and unducted propellers of the same thrust operating under similar conditions are investigated. An FEM model is created for the generation, propagation, and radiation of steady, rotor alone noise and exit guide vane interaction noise of a ducted fan. For a specified number of blades, angular mode harmonic, and rotor angular velocity, the acoustic field is described in a cylindrical coordinate system reduced to only the axial and radial directions. It is found that, contrary to the usual understanding of the Tyler and Sofrin (1962) result, supersonic tip speed rotor noise can be cut off if the tip Mach number is only slightly in excess of unity and if the number of blades is relatively small. If there are many blades, the fundamental angular mode number is large, and the Tyler and Sofrin result for thin annuli becomes more relevant. Shrouding of subsonic tip speed propellers is a very effective means of controlling rotor alone noise.

  6. Pancreatographic investigation of pancreatic duct system and pancreaticobiliary malformation

    PubMed Central

    Kamisawa, Terumi; Okamoto, Atsutake

    2008-01-01

    To clarify the anatomy of the pancreatic duct system and to investigate its embryology, we reviewed 256 pancreatograms with normal pancreatic head, 81 with pancreas divisum and 74 with pancreaticobiliary maljunction. Accessory pancreatograms were divided into two patterns. The long-type accessory pancreatic duct forms a straight line and joins the main pancreatic duct at the neck portion of the pancreas. The short-type accessory pancreatic duct joins the main pancreatic duct near its first inferior branch. The short-type accessory pancreatic duct is less likely to have a long inferior branch arising from the accessory pancreatic duct. The length of the accessory pancreatic duct from the orifice to the first long inferior branch was similar in the short- and long-type accessory pancreatic ducts. The first long inferior branch from the long-type accessory pancreatic duct passes though the main pancreatic duct near the origin of the inferior branch from the main pancreatic duct. Immunohistochemically, in the short-type accessory pancreatic duct, the main pancreatic duct between the junction with the short-type accessory pancreatic duct and the neck portion was located in the ventral pancreas. The long-type accessory pancreatic duct represents a continuation of the main duct of the dorsal pancreatic bud. The short-type accessory pancreatic duct is probably formed by the proximal main duct of the dorsal pancreatic bud and its long inferior branch. PMID:18194203

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

    MedlinePlus

    ... Topic Additional resources for bile duct cancer What’s new in bile duct cancer research and treatment? Bile ... is tumor blood vessels. Bile duct tumors need new blood vessels to grow beyond a certain size. ...

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

    SciTech Connect

    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.

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

    SciTech Connect

    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.

  10. Do We Know What Causes Bile Duct Cancer?

    MedlinePlus

    ... duct cancer be prevented? Do we know what causes bile duct cancer? We don’t know the exact cause of ... to top » Guide Topics What Is Bile Duct Cancer? Causes, Risk Factors, and Prevention Early Detection, Diagnosis, and ...

  11. Extracorporeal shockwave lithotripsy of pancreatic duct stones.

    PubMed

    Rawat, B; Fache, J S; Burhenne, H J

    1992-01-01

    Encouraging results with extracorporeal shockwave lithotripsy (ESWL) for pancreatic duct stones have been reported from Europe. We present our experience with the first two North American patients, treated with excellent results in one and limited clinical improvement in the other patient at 1 year follow-up. Targeting of pancreatic duct stones was achieved with either fluoroscopy or ultrasound.

  12. Double-duct liquid metal magnetohydrodynamic engine

    DOEpatents

    Haaland, Carsten M.

    1995-01-01

    An internal combustion, liquid metal (LM) magnetohydrodynamic (MHD) engine and an alternating current (AC) magnetohydrodynamic generator, are used in combination to provide useful AC electric energy output. The engine design has-four pistons and a double duct configuration, with each duct containing sodium potassium liquid metal confined between free pistons located at either end of the duct. The liquid metal is forced to flow back and forth in the duct by the movement of the pistons, which are alternatively driven by an internal combustion process. In the MHD generator, the two LM-MHD ducts pass in close proximity through a Hartmann duct with output transformer. AC power is produced by operating the engine with the liquid metal in the two generator ducts always flowing in counter directions. The amount of liquid metal maintained in the ducts may be varied. This provides a variable stroke length for the pistons. The engine/generator provides variable AC power at variable frequencies that correspond to the power demands of the vehicular propulsion. Also the engine should maintain nearly constant efficiency throughout the range of power usage. Automobiles and trucks could be powered by the invention, with no transmission or power converter devices being required.

  13. Double-duct liquid metal magnetohydrodynamic engine

    DOEpatents

    Haaland, Carsten M.

    1997-01-01

    An internal combustion, liquid metal (LM) magnetohydrodynamic (MHD) engine and an alternating current (AC) magnetohydrodynamic generator, are used in combination to provide useful AC electric energy output. The engine design has four pistons and a double duct configuration, with each duct containing sodium potassium liquid metal confined between free pistons located at either end of the duct. The liquid metal is forced to flow back and forth in the duct by the movement of the pistons, which are alternatively driven by an internal combustion process. In the MHD generator, the two LM-MHD ducts pass in close proximity through a Hartmann duct with output transformer. AC power is produced by operating the engine with the liquid metal in the two generator ducts always flowing in counter directions. The amount of liquid metal maintained in the ducts may be varied. This provides a variable stroke length for the pistons. The engine/generator provides variable AC power at variable frequencies that correspond to the power demands of the vehicular propulsion. Also the engine should maintain nearly constant efficiency throughout the range of power usage. Automobiles and trucks could be powered by the invention, with no transmission or power converter devices being required.

  14. 46 CFR 116.610 - Ventilation ducts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... materials are not allowed within ventilation ducts. However, metal piping and electrical wiring installed in a metal protective enclosure may be installed within ventilation ducts, provided that the piping or... prevent corrosion; (4) Fire dampers must be capable of manual operation from outside the space served,...

  15. Borescope Device Takes Impressions In Ducts

    NASA Technical Reports Server (NTRS)

    Walter, Richard F.; Turner, Laura J.

    1990-01-01

    Maneuverable device built around borescope equipped to make impression molds of welded joints in interior surfaces of ducts. Molds then examined to determine degress of mismatch in welds. Inserted in duct, and color-coded handles on ends of cables used to articulate head to maneuver around corners. Use of device fairly easy and requires little training.

  16. Rocket-in-a-Duct Performance Analysis

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Reed, Brian D.

    1999-01-01

    An axisymmetric, 110 N class, rocket configured with a free expansion between the rocket nozzle and a surrounding duct was tested in an altitude simulation facility. The propellants were gaseous hydrogen and gaseous oxygen and the hardware consisted of a heat sink type copper rocket firing through copper ducts of various diameters and lengths. A secondary flow of nitrogen was introduced at the blind end of the duct to mix with the primary rocket mass flow in the duct. This flow was in the range of 0 to 10% of the primary massflow and its effect on nozzle performance was measured. The random measurement errors on thrust and massflow were within +/-1%. One dimensional equilibrium calculations were used to establish the possible theoretical performance of these rocket-in-a-duct nozzles. Although the scale of these tests was small, they simulated the relevant flow expansion physics at a modest experimental cost. Test results indicated that lower performance was obtained at higher free expansion area ratios and longer ducts, while, higher performance was obtained with the addition of secondary flow. There was a discernable peak in specific impulse efficiency at 4% secondary flow. The small scale of these tests resulted in low performance efficiencies, but prior numerical modeling of larger rocket-in-a-duct engines predicted performance that was comparable to that of optimized rocket nozzles. This remains to be proven in large-scale, rocket-in-a-duct tests.

  17. Navier-Stokes analysis and experimental data comparison of compressible flow within ducts

    NASA Technical Reports Server (NTRS)

    Harloff, G. J.; Reichert, B. A.; Sirbaugh, J. R.; Wellborn, S. R.

    1992-01-01

    Many aircraft employ ducts with centerline curvature or changing cross-sectional shape to join the engine with inlet and exhaust components. S-ducts convey air to the engine compressor from the intake and often decelerate the flow to achieve an acceptable Mach number at the engine compressor by increasing the cross-sectional area downstream. Circular-to-rectangular transition ducts are used on aircraft with rectangular exhaust nozzles to connect the engine and nozzle. To achieve maximum engine performance, the ducts should minimize flow total pressure loss and total pressure distortion at the duct exit. Changes in the curvature of the duct centerline or the duct cross-sectional shape give rise to streamline curvature which causes cross stream pressure gradients. Secondary flows can be caused by deflection of the transverse vorticity component of the boundary layer. This vortex tilting results in counter-rotating vortices. Additionally, the adverse streamwise pressure gradient caused by increasing cross-sectional area can lead to flow separation. Vortex pairs have been observed in the exit planes of both duct types. These vortices are due to secondary flows induced by pressure gradients resulting from streamline curvature. Regions of low total pressure are produced when the vortices convect boundary layer fluid into the main flow. The purpose of the present study is to predict the measured flow field in a diffusing S-duct and a circular-to-rectangular transition duct with a full Navier-Stokes computer program, PARC3D, and to compare the numerical predictions with new detailed experimental measurements. The work was undertaken to extend previous studies and to provide additional CFD validation data needed to help model flows with strong secondary flow and boundary layer separation. The S-duct computation extends the study of Smith et al, and Harloff et al, which concluded that the computation might be improved by using a finer grid and more advanced turbulence models

  18. Cholangiographic evaluation of bile duct carcinoma

    SciTech Connect

    Nichols, D.A.; MacCarty, R.L.; Gaffey, T.A.

    1983-12-01

    Cholangiograms and clinical histories of 82 patients with biopsy-proved bile duct carcinoma were reviewed. The carcinomas were classified according to morphologic findings and clinical outcome. Ulcerative colitis and antecedent inflammatory disease of the biliary tree, particularly primary sclerosing cholangitis, seem to predispose to the development of bile duct carcinoma. Focal stenotic lesions were the most common morphologic type (62/82). Polypoid carcinomas and diffuse sclerosing carcinomas were less common and of about equal frequency. Prognosis was best for patients with polypoid carcinomas and worst for those with diffuse sclerosing carcinomas. In 69 cases (84%), the tumors involved the intrahepatic or proximal extrahepatic ducts, makin curative resection difficult or impossible. Patients with carcinomas limited to the more distal extrahepatic bile ducts had a longer average survival and a higher probability of surgical cure. Proper management of patients with bile duct carcinoma requires a complete and accurate cholangiographic evaluation of the morphology, location, and extent of the disease.

  19. Technology Solutions Case Study: Ducts Sealing Using Injected Spray Sealant

    SciTech Connect

    2014-03-01

    In multifamily and attached buildings, traditional duct sealing methods are often impractical or costly and disruptive because of the difficulty in accessing leakage sites. In this project, the Raleigh Housing Authority worked with Building America team, the Advanced Residential Integrated Solutions Collaborative to determine the most cost-effective ways to reduce duct leakage in its low-rise housing units.Two retrofit duct sealing techniques—manually-applied sealants and injecting a spray sealant—were implemented in several low-rise multiunit buildings. An analysis on the cost and performance of the two methods are presented. Each method was used in twenty housing units: approximately half of each group of units are single story and the remainder two-story. Results show that duct leakage to the outside was reduced by an average of 59% through the use of manual methods, and by 90% in the units where the injected spray sealant was used. Ihe cost of manually-applying sealant ranged from $275 to $511 per unit and for the injected spray sealant the cost was $700 per unit. Modeling suggests a simple payback of 2.2 years for manual sealing and 4.7 years for the injected spray sealant system. Utility bills were collected for one year before and after the retrofits. Utility bill analysis shows 14% and 16% energy savings using injected spray sealant system and hand sealing procedure respectively in heating season whereas in cooling season, energy savings using injected spray sealant system and hand sealing were both 16%.

  20. Techniques of Fluorescence Cholangiography During Laparoscopic Cholecystectomy for Better Delineation of the Bile Duct Anatomy

    PubMed Central

    Kono, Yoshiharu; Ishizawa, Takeaki; Tani, Keigo; Harada, Nobuhiro; Kaneko, Junichi; Saiura, Akio; Bandai, Yasutsugu; Kokudo, Norihiro

    2015-01-01

    Abstract To evaluate the clinical and technical factors affecting the ability of fluorescence cholangiography (FC) using indocyanine green (ICG) to delineate the bile duct anatomy during laparoscopic cholecystectomy (LC). Application of FC during LC began after laparoscopic fluorescence imaging systems became commercially available. In 108 patients undergoing LC, FC was performed by preoperative intravenous injection of ICG (2.5 mg) during dissection of Calot's triangle, and clinical factors affecting the ability of FC to delineate the extrahepatic bile ducts were evaluated. Equipment-related factors associated with bile duct detectability were also assessed among 5 laparoscopic systems and 1 open fluorescence imaging system in ex vivo studies. FC delineated the confluence between the cystic duct and common hepatic duct (CyD–CHD) before and after dissection of Calot's triangle in 80 patients (74%) and 99 patients (92%), respectively. The interval between ICG injection and FC before dissection of Calot's triangle was significantly longer in the 80 patients in whom the CyD–CHD confluence was detected by fluorescence imaging before dissection (median, 90 min; range, 15–165 min) than in the remaining 28 patients in whom the confluence was undetectable (median, 47 min; range, 21–205 min; P < 0.01). The signal contrast on the fluorescence images of the bile duct samples was significantly different among the laparoscopic imaging systems and tended to decrease more steeply than those of the open imaging system as the target-laparoscope distance increased and porcine tissues covering the samples became thicker. FC is a simple navigation tool for obtaining a biliary roadmap to reach the “critical view of safety” during LC. Key factors for better bile duct identification by FC are administration of ICG as far in advance as possible before surgery, sufficient extension of connective tissues around the bile ducts, and placement of the tip of

  1. Duct Remediation Program: Remediation operations and implementation

    SciTech Connect

    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. Magnetospheric whistler ducts observed by ISIS satellites

    NASA Technical Reports Server (NTRS)

    Ondoh, T.

    1976-01-01

    The latitudinal width of the magnetospheric whistler duct has been estimated by the first and final invariant latitudes of whistler echoes and the conservation of the magnetic flux for the centered dipole field, using 105 whistler echoes in ISIS VLF data received at Kashima, Japan for 1972-1973. The latitudinal distribution of whistler duct occurrence shows a maximum at invariant latitudes of 40-45 degrees near the maximum occurrence latitude of ground whistlers. The radial width of magnetospheric whistler duct in the geomagnetically equatorial plane increases with invariant latitude of the geomagnetic flux tube in which whistlers propagate.

  3. [Degenerated papillomatosis of the bile duct].

    PubMed

    De Castro Gutiérrez, J; Armengol Carrasco, M; Oller Sales, B; Fdez-Llamazares Rodríguez, J; Julián Ibáñez, J F; Broggi Trías, M A; Salvá Lacombe, J A

    1989-07-01

    Papillomatosis of the biliary ducts is exceptional. It is defined by the presence of multiple, benign, papillary type, epithelial tumors on the choledochus and hepatic ducts, and can also effect the gallbladder and intrahepatic bile ducts. It courses with a tendency to recurrence and secondary degeneration, and its prognosis is uncertain and sometimes grave. The treatment is surgical and depends on the extension of the lesions, often being only palliative. The techniques of choice are curettage and biliodigestive derivation. A case is presented of degenerated papillomatosis treated by cephalic duodenopancreatectomy and cholecystectomy.

  4. How Is Bile Duct Cancer Diagnosed?

    MedlinePlus

    ... line through which a different kind of contrast dye (IV contrast) is injected. This helps better outline ... common bile duct. A small amount of contrast dye is injected through the tube to help outline ...

  5. Spontaneous rupture of the common bile duct.

    PubMed

    Kyzer, S; Bayer, I; Chaimoff, C

    1986-01-01

    Spontaneous rupture of the common bile duct in adults is very rare. The authors report only the 14th case in the Western literature. A 25-year-old woman had signs of peritonitis suggestive of a perforated appendix, but at operation the appendix appeared normal and a large amount of bile was found in the peritoneal cavity. A 2-mm tear was found on the anterior wall of the common bile duct. The patient recovered without complications after T-tube drainage and cholecystectomy. In this patient none of the factors thought to cause spontaneous rupture of the common bile duct were present, so the authors conclude that the case may be classified as idiopathic spontaneous rupture of the common bile duct. PMID:3940592

  6. Rotating Rake Turbofan Duct Mode Measurement System

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.

    2005-01-01

    An experimental measurement system was developed and implemented by the NASA Glenn Research Center in the 1990s to measure turbofan duct acoustic modes. The system is a continuously rotating radial microphone rake that is inserted into the duct. This Rotating Rake provides a complete map of the acoustic duct modes present in a ducted fan and has been used on a variety of test articles: from a low-speed, concept test rig, to a full-scale production turbofan engine. The Rotating Rake has been critical in developing and evaluating a number of noise reduction concepts as well as providing experimental databases for verification of several aero-acoustic codes. More detailed derivation of the unique Rotating Rake equations are presented in the appendix.

  7. Investigation of heat transfer in porous duct

    NASA Astrophysics Data System (ADS)

    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.

  8. Treatment Options for Extrahepatic Bile Duct Cancer

    MedlinePlus

    ... checked to measure the amounts of bilirubin and alkaline phosphatase released into the blood by the liver. ... which a stent (a thin, flexible tube or metal tube) is placed in the bile duct to ...

  9. Treatment Option Overview (Extrahepatic Bile Duct Cancer)

    MedlinePlus

    ... checked to measure the amounts of bilirubin and alkaline phosphatase released into the blood by the liver. ... which a stent (a thin, flexible tube or metal tube) is placed in the bile duct to ...

  10. Stages of Extrahepatic Bile Duct Cancer

    MedlinePlus

    ... checked to measure the amounts of bilirubin and alkaline phosphatase released into the blood by the liver. ... which a stent (a thin, flexible tube or metal tube) is placed in the bile duct to ...

  11. Bile Duct (Cholangiocarcinoma) Cancer: Radiation Therapy

    MedlinePlus

    ... form of radiation for bile duct cancer. External beam radiation therapy (EBRT) This type of radiation therapy ... determine the correct angles for aiming the radiation beams and the proper dose of radiation. The treatment ...

  12. INTERIOR DUCT SYSTEM DESIGN, CONSTRUCTION, AND PERFORMANCE

    SciTech Connect

    Janet E.R. Mcllvaine; David Beal; Philip Fairey

    2001-10-10

    By removing air distribution and conditioning equipment from unconditioned spaces, homeowners stand to benefit substantially with respect to both energy savings and indoor air quality. Duct leakage introduces: Greater heating and cooling loads from air at extreme temperatures and humidity levels; Outside air and air from unconditioned spaces that may contain air borne contaminants, combustion gases, pollen, mold spores, and/or particles of building materials; and Higher whole-house infiltration/exfiltration rates. Exemplary studies conducted since 1990 have demonstrated the prevalence of duct leakage throughout the United States and measured energy savings of approximately 20% during both heating and cooling seasons from leakage reduction. These all dealt with duct leakage to and/or from unconditioned spaces. In the building science community, leakage within the conditioned space is generally presumed to eliminate the negative consequences of duct leakage with the exception of possibly creating pressure imbalances in the house which relates to higher infiltration and/or exfiltration. The practical challenges of isolating ducts and air handlers from unconditioned spaces require builders to construct an air-tight environment for the ducts. Florida Solar Energy Center researchers worked with four builders in Texas, North Carolina, and Florida who build a furred-down chase located either in a central hallway or at the edges of rooms as an architectural detail. Some comparison homes with duct systems in attics and crawl spaces were included in the test group of more than 20 homes. Test data reveals that all of the duct/AHU systems built inside the conditioned space had lower duct leakage to unconditioned spaces than their conventional counterparts; however, none of the homes was completely free of duct leakage to unconditioned spaces. Common problems included wiring and plumbing penetrations of the chase, failure to treat the chase as an air tight space, and misguided

  13. Transition duct assembly with modified trailing edge in turbine system

    DOEpatents

    McMahan, Kevin Weston; Schott, Carl Gerard; Ingram, Clint Luigie; Siden, Gunnar Leif; Pierre, Sylvain

    2016-10-04

    Transition duct assemblies for turbine systems and turbomachines are provided. In one embodiment, a transition duct assembly includes a plurality of transition ducts disposed in a generally annular array and comprising a first transition duct and a second transition duct. Each of the plurality of transition ducts 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 each transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct assembly further includes an aerodynamic structure defined by the passages of the first transition duct and the second transition duct. The aerodynamic structure includes a pressure side, a suction side, and a trailing edge, the trailing edge having a modified aerodynamic contour.

  14. [Extracorporeal shockwave lithotripsy of bile duct calculi].

    PubMed

    Greiner, L; Jakobeit, C

    1993-08-01

    Shockwave therapy of bile duct stones is not dependent on difficult preconditions concerning stone-volume and -composition or subsequent lythic therapy. Its main indication is failure of endoscopic sphincterotomy (EST). Shockwave lithotripsy of bile duct stones--which may even be carried out even instead of EST in specific cases--is with a success rate of 80 to 95% as effective as shockwave lithotripsy in urology.

  15. Measurement of insertion loss of ducted silencers

    NASA Astrophysics Data System (ADS)

    Iho, L.; Jonasson, H.

    1980-05-01

    Measurements were carried out with different sound sources, with and without terminating transmission element, with and without vibration isolation, with different duct lengths and with different transition elements at different positions. Testing was done in the 1/3 octave band in a reverberation room. The Based on the conclusions, a revised method for measuring the transmission loss of ducted silencers without air flow is proposed.

  16. Lapatinib in Treating Patients With Locally Advanced or Metastatic Biliary Tract or Liver Cancer That Cannot Be Removed By Surgery

    ClinicalTrials.gov

    2014-12-18

    Adult Primary Hepatocellular Carcinoma; Advanced Adult Primary Liver Cancer; Localized Unresectable Adult Primary Liver Cancer; Recurrent Adult Primary Liver Cancer; Recurrent Extrahepatic Bile Duct Cancer; Recurrent Gallbladder Cancer; Unresectable Extrahepatic Bile Duct Cancer; Unresectable Gallbladder Cancer

  17. Fundamental investigation of duct/ESP phenomena

    SciTech Connect

    Durham, M.D.; Ebner, T.G.; Holstein, D.B.

    1991-03-07

    This report describes the results of pilot plant tests to characterize the performance of an electrostatic precipitation (ESP) operating downstream of an in-duct scrubbing system. The test program was conducted at a 1.7 MW duct injection/ESP pilot plant that was located at the Central Illinois Public Service Company's Meredosia Station. The pilot plant was installed during the summer of 1989 and testing was conducted from September, 1989 to October, 1990. In addition to the tests to characterize the ESPs, a parametric evaluation of sulfur dioxide removal by duct sorbent injection was conducted concurrently. Another aspect of this program related to ESP performance was the development of a mathematical model to predict ESP performance at duct injection conditions. Air load and gas load tests were conducted to demonstrate that the ESP was functioning properly. The ESP was then evaluated at flyash conditions to establish baseline operation. A series of tests were than conducted at duct injection conditions. Different humidification configurations were investigated and both lime only and lime with recycle injection were tested. A final set of tests were directed at evaluating different ESP upgrade technologies that could improve performance under duct injection conditions. In addition to the Meredosia pilot plant tests, tests were conducted to characterize the performance of the ESP operating as part of the demonstration of the Coolside Process at the Edgewater plant in Lorrain, Ohio. 41 refs., 97 figs., 43 tabs.

  18. A Comparison of Simulation Capabilities for Ducts

    SciTech Connect

    Miller, William A.; Smith, Matt K.; Gu, Lixing; New, Joshua Ryan

    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.

  19. Sound radiation from a flanged inclined duct.

    PubMed

    McAlpine, Alan; Daymond-King, Alex P; Kempton, Andrew J

    2012-12-01

    A simple method to calculate sound radiation from a flanged inclined duct is presented. An inclined annular duct is terminated by a rigid vertical plane. The duct termination is representative of a scarfed exit. The concept of a scarfed duct has been examined in turbofan aero-engines as a means to, potentially, shield a portion of the radiated sound from being transmitted directly to the ground. The sound field inside the annular duct is expressed in terms of spinning modes. Exterior to the duct, the radiated sound field owing to each mode can be expressed in terms of its directivity pattern, which is found by evaluating an appropriate form of Rayleigh's integral. The asymmetry is shown to affect the amplitude of the principal lobe of the directivity pattern, and to alter the proportion of the sound power radiated up or down. The methodology detailed in this article provides a simple engineering approach to investigate the sound radiation for a three-dimensional problem.

  20. Intraductal carcinoma of the prostate in the ejaculatory duct.

    PubMed

    Sanchez-Salazar, Alma J; Basler, Joseph W; Nicolas, Marlo M

    2010-08-01

    Intraductal carcinoma of the prostate (IDCP) involving prostatic ducts and acini is a well-known phenomenon typically seen in a background of high-grade invasive prostatic adenocarcinoma. The current case of prostatic adenocarcinoma with Gleason score of 9 (4 + 5) invades the ejaculatory ducts, left seminal vesicle, and extraprostatic tissue. The tumor involving the left ejaculatory duct spans the lumen with preservation of native duct architecture, including basal cells, similar features described in IDCP involving prostatic ducts and acini. PMID:20444733

  1. Duct injection technology prototype development: Nozzle development Subtask 4. 1, Atomizer specifications for duct injection technology

    SciTech Connect

    Not Available

    1992-02-01

    Babcock Wilcox has conducted a program to identify atomizers appropriate for successful in-duct injection of humidification water and lime slurries. The purpose of this program was to identify and quantify atomizer spray and performance criteria that affect the operations and reliability of the in-duct SO{sub 2} removal process, and compare commercially available atomizers to these criteria.

  2. Cavitation erosion in blocked flow with a ducted ice-class propeller

    SciTech Connect

    Doucet, J.M.; Bose, N.; Walker, D.; Jones, S.J.

    1996-12-31

    Ships that operate in ice often encounter momentary increased propeller cavitation because ice pieces block the flow into the propeller. For ducted propellers, this additional cavitation is more significant than it is for open propellers; ice pieces may become lodged against and within the duct and subject the propeller to longer periods of increased cavitation due to the blocked flow. Associated with this blocked flow is the possibility of cavitation erosion on the propeller. An erosion study, using paint films, was conducted in a cavitation tunnel with a model propeller of the type fitted to the Canadian Marine Drilling Ltd. vessel MV Robert LeMeur. A simulated ice blockage was installed ahead of the propeller model and within the duct. Tests were carried out over a range of advance coefficients for various test conditions. The resulting types of cavitation were documented, the erosion patterns were photographed and comparisons between each test were made.

  3. Duct-to-mucosa pancreatojejunostomy for small main pancreatic duct by the parachute technique after pancreatoduodenectomy.

    PubMed

    Okamoto, Kojun; Koyama, Isamu; Toshimitsu, Yasuko; Aikawa, Masayasu; Okada, Katsuya; Ueno, Yosuke; Miyazawa, Mitsuo

    2011-01-01

    A duct-to-mucosa pancreatojejunostomy is technically difficult to perform for a small main pancreatic duct after pancreatoduodenectomy. Our group applied the parachute technique to reconstruct and attach a small pancreatic duct to the jejunal mucosa. This method makes it very easy to position stitches on the posterior row of the anastomosis. It also allows a complete view of every stitch, both inside and outside the pancreatic duct and jejunal wall. Sixteen patients underwent pancreatoduodenectomy followed by duct-to-mucosa pancreatojejunostomy by the parachute technique. Pancreatic fistulae developed in 3 of the patients, but none of the fistulae were severe. The median postoperative hospital stay was 14.5 days, and there were no postoperative deaths during that time. In conclusion, pancreatojejunostomy by the parachute technique is a simple method with a very low risk of pancreatic fistula formation and a considerably shortened postoperative hospital stay. The method is also useful for reconstruction with pancreatojejunostomy after pancreatoduodenectomy.

  4. A case of adenosquamous carcinoma of the lower bile duct diagnosed preoperatively via transpapillary biopsy.

    PubMed

    Yokoyama, Yoshihiro; Iida, Tomoya; Kaneto, Hiroyuki; Yamamoto, Itaru; Murakami, Kayo; Satoh, Shuji; Shimizu, Haruo; Sasaki, Kenichi; Konishi, Yasuhiro; Kon, Shinichiro

    2016-08-01

    A 78-year-old man presented to our hospital with fever and brownish urine. Upon thorough examination, a diagnosis of obstructive jaundice and acute cholangitis associated with a lower bile duct tumor was made. Endoscopic retrograde cholangiopancreatography revealed entire circumferential stenosis of the lower bile duct. Examination of a transpapillary biopsy specimen of the lesion suggested adenosquamous carcinoma. The patient underwent subtotal stomach-preserving pancreaticoduodenectomy. Histopathological examination revealed adenocarcinoma of the lower bile duct and squamous cell carcinoma components;a case of adenosquamous carcinoma was accordingly diagnosed. The lower bile duct tumor directly extended into the pancreatic parenchyma for approximately 1mm. We performed radical surgery and administered adjuvant chemotherapy with gemcitabine because of advanced neural invasion after consulting with the patient. There was no sign of recurrence 46 months after surgery. As adenosquamous carcinoma of the extrahepatic bile duct is rare, it is difficult to preoperatively diagnose the condition. Only a few cases have been reported till date. PMID:27498940

  5. Late Probing for Congenital Nasolacrimal Duct Obstruction

    PubMed Central

    Abrishami, Mohammad; Bagheri, Abbas; Salour, Soltan-Hossein; Mirdehghan, S. Ali

    2009-01-01

    Purpose To report the results of late nasolacrimal duct probing in patients with congenital nasolacrimal duct obstruction (NLDO). Methods This retrospective study was performed on a consecutive series of patients with congenital NLDO who underwent late (after 15 months of age) nasolacrimal duct probing for the first time. Results Over a period of five years, 158 patients including 75 (47.4%) male and 83 (52.6%) female subjects with mean age of 3±4.2 years (range, 15 months to 37 years) underwent initial probing for NLDO. Nasolacrimal duct probing was performed unilaterally in 78% and bilaterally in 22% of the patients. Success rate was 75% overall, 72% in unilateral cases and 83% in bilateral instances. Success rate was not correlated with age at intervention. Conclusion Nasolacrimal duct probing seems to be reasonably successful for treatment of congenital NLDO in patients older than 15 months who are seen for the first time. Silicone intubation or dacryocystorhinostomy should be reserved for refractory cases. PMID:23198056

  6. Convolution seal for transition duct in turbine system

    SciTech Connect

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

    2015-05-26

    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 feature for interfacing with an adjacent transition duct. The turbine system further includes a convolution seal contacting the interface feature to provide a seal between the interface feature and the adjacent transition duct.

  7. User's Manual for DuctE3D: A Program for 3D Euler Unsteady Aerodynamic and Aeroelastic Analysis of Ducted Fans

    NASA Technical Reports Server (NTRS)

    Srivastava, R.; Reddy, T. S. R.

    1997-01-01

    The program DuctE3D is used for steady or unsteady aerodynamic and aeroelastic analysis of ducted fans. This guide describes the input data required and the output files generated, in using DuctE3D. The analysis solves three dimensional unsteady, compressible Euler equations to obtain the aerodynamic forces. A normal mode structural analysis is used to obtain the aeroelastic equations, which are solved using either the time domain or the frequency domain solution method. Sample input and output files are included in this guide for steady aerodynamic analysis and aeroelastic analysis of an isolated fan row.

  8. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1993-01-01

    Condensation heat transfer in a horizontal rectangular duct was experimentally and analytically investigated. To prevent the dripping of condensate on the film, the experiment was conducted inside a horizontal rectangular duct with vapor condensing only on the bottom cooled plate of the duct. R-113 and FC-72 (Fluorinert Electronic Fluid developed by the 3M Company) were used as the condensing fluids. The experimental program included measurements of film thickness, local and average heat transfer coefficients, wave length, wave speed, and a study of wave initiation. The measured film thickness was used to obtain the local heat transfer coefficient. The wave initiation was studied both with condensation and with an adiabatic air-liquid flow. The test sections used in both experiments were identical.

  9. Laserlithotripsy of common bile duct stones.

    PubMed Central

    Ell, C; Lux, G; Hochberger, J; Müller, D; Demling, L

    1988-01-01

    Endoscopic retrograde laser lithotripsy of common bile duct stones is a new technique which can be carried out through the endoscope without anaesthesia using ordinary endoscopic equipment. In the method described here a flashlamp pulsed Neodymium YAG laser (wave length 1064 nm) was used. Light energy was transmitted along a highly flexible quartz fibre with a diameter of 0.2 mm. This new technique was used in nine patients with concrements in the common bile duct, which could not be removed with the established endoscopic techniques. In eight of the nine the concrements (maximum diameter 4.7 x 3.1 cm) could be fragmented and in six the fragments could be extracted from the common bile duct. The total energy required was 80-300 J; complications were not observed. Images Figs 3 and 4 Fig. 5 Fig. 6 Fig. 7 Figs 8 and 9 PMID:2898421

  10. Acoustic energy in ducts - Further observations

    NASA Technical Reports Server (NTRS)

    Eversman, W.

    1979-01-01

    The transmission of acoustic energy in uniform ducts carrying uniform flow is investigated with the purpose of clarifying two points of interest. The two commonly used definitions of acoustic 'energy' flux are shown to be related by a Legendre transformation of the Lagrangian density exactly as in deriving the Hamiltonian density in mechanics. In the acoustic case the total energy density and the Hamiltonian density are not the same which accounts for two different 'energy' fluxes. When the duct has acoustically absorptive walls neither of the two flux expressions gives correct results. A reevaluation of the basis of derivation of the energy density and energy flux provides forms which yield consistent results for soft walled ducts.

  11. Evaluation of PEGIT duct connection system

    SciTech Connect

    Walker, Iain S.; Brenner, Douglas E.; Sherman, Max H.; Dickerhoff, Darryl J.

    2003-08-01

    Most air duct system components are assembled in the field and are mechanically fastened by sheet metal screws (for sheet metal-to-sheet metal) or by drawbands (for flex duct-to-sheet metal). Air sealing is separate from this mechanical fastening and is usually achieved using tape or mastic products after mechanical fastening. Field observations have shown that mechanical fastening rarely meets code or manufacturers requirements and that sealing procedures are similarly inconsistent. To address these problems, Proctor Engineering Group (PEG) is developing a system of joining ducts (called PEGIT) that combines the mechanical fastening and sealing into a single self-contained procedure. The PEGIT system uses a shaped flexible seal between specially designed sheet metal duct fittings to both seal and fasten duct sections together. Figure 1 shows the inner duct fitting complete with rubber seal. This seal provides the air seal for the completed fitting and is shaped to allow the inner and outer fittings to slide together, and then to lock the fittings in place. The illustration in Figure 2 shows the approximate cross section of the rubber seal that shows how the seal has a lip that is angled backwards. This angled lip allows the joint to be pushed together by folding flat but then its long axis makes it stiff in the pulling apart direction. This study was undertaken to assist PEG in some of the design aspects of this system and to test the performance of the PEGIT system. This study was carried out in three phases. The initial phase evaluated the performance of a preliminary seal design for the PEGIT system. After the first phase, the seal was redesigned and this new seal was evaluated in the second phase of testing. The third phase performed more detailed testing of the second seal design to optimize the production tolerances of the sheet metal fittings. This report summarizes our findings from the first two phases and provides details about the third phase of testing.

  12. Fundamental investigation of duct/ESP phenomena

    SciTech Connect

    Brown, C.A. ); Durham, M.D. ); Sowa, W.A. . Combustion Lab.); Himes, R.M. ); Mahaffey, W.A. )

    1991-10-21

    Radian Corporation was contracted to investigate duct injection and ESP phenomena in a 1.7 MW pilot plant constructed for this test program. This study was an attempt to resolve problems found in previous studies and answer remaining questions for the technology using an approach which concentrates on the fundamental mechanisms of the process. The goal of the study was to obtain a better understanding of the basic physical and chemical phenomena that control: (1) the desulfurization of flue gas by calcium-based reagent, and (2) the coupling of an existing ESP particulate collection device to the duct injection process. Process economics are being studied by others. (VC)

  13. Computing Propagation Of Sound In Engine Ducts

    NASA Technical Reports Server (NTRS)

    Saylor, Silvia

    1995-01-01

    Frequency Domain Propagation Model (FREDOM) computer program accounts for acoustic loads applied to components of engines. Models propagation of noise through fluids in ducts between components and through passages within components. Used not only to analyze hardware problems, but also for design purposes. Updated version of FREQPL program easier to use. Devised specifically for use in analyzing acoustic loads in rocket engines. Underlying physical and mathematical concepts implemented also applicable to acoustic propagation in other enclosed spaces; analyzing process plumbing and ducts in industrial buildings with view toward reducing noise in work areas.

  14. Inverse potential scattering in duct acoustics.

    PubMed

    Forbes, Barbara J; Pike, E Roy; Sharp, David B; Aktosun, Tuncay

    2006-01-01

    The inverse problem of the noninvasive measurement of the shape of an acoustical duct in which one-dimensional wave propagation can be assumed is examined within the theoretical framework of the governing Klein-Gordon equation. Previous deterministic methods developed over the last 40 years have all required direct measurement of the reflectance or input impedance but now, by application of the methods of inverse quantum scattering to the acoustical system, it is shown that the reflectance can be algorithmically derived from the radiated wave. The potential and area functions of the duct can subsequently be reconstructed. The results are discussed with particular reference to acoustic pulse reflectometry.

  15. Acoustic impedance of curved multilayered duct liners

    NASA Technical Reports Server (NTRS)

    Zorumski, W. E.

    1973-01-01

    The effect of curvature of annular duct liners on the liner acoustic impedance is examined. Exact equations are derived for the impedance of point reacting liners which are made from an arbitrary number of thin cylindrical layers of porous material separated by small radially oriented cells. Equations are given for liners with convex curvature and for liners with concave curvature. For ducts with small curvature, it is shown that these equations reduce to the equations for a flat liner. It is shown, by analytical and numerical examples, that the effect of liner curvature is significant in practical noise reduction problems.

  16. Parotid duct cyst: a case report.

    PubMed

    Erkan, A N; Hürcan, C; Bal, N; Yilmazer, C; Ozlüoglu, L

    2006-01-01

    Salivary gland cysts can be benign or malignant. Salivary duct cysts are benign tumours that occur mainly in the parotid gland and represent 10% of all salivary gland cysts. We report the case of a 48-year-old man who presented with a painless preauricular mass on the right side. Superficial parotidectomy was performed based on magnetic resonance imaging (MRI). Histopathologic examination of the specimen revealed a parotid duct cyst. Here we report clinical features, diagnosis, and treatment of the case as well as a review of the literature.

  17. Limits of Surgical Resection for Bile Duct Cancer

    PubMed Central

    Bartsch, Fabian; Heinrich, Stefan; Lang, Hauke

    2015-01-01

    Introduction Perihilar cholangiocarcinoma is the most frequent cholangiocarcinoma and poses difficulties in preoperative evaluation. For its therapy, often major hepatic resections as well as resection and reconstruction of the hepatic artery or the portal vein are necessary. In the last decades, great advances were made in both the surgical procedures and the perioperative anesthetic management. In this article, we describe from our point of view which facts represent the limits for curative (R0) resection in perihilar cholangiocarcinoma. Methods Retrospective data of a 6-year period (2008-2014) was collected in an SPSS 22 database and further analyzed with focus on the surgical approach and the postoperative as well as histological results. Results Out of 96 patients in total we were able to intend a curative resection in 73 patients (76%). In 58/73 (79.5%) resections an R0 situation could be reached (R1 n = 14; R2 n = 1). 23 patients were irresectable because of peritoneal carcinosis (n = 8), broad infiltration of major blood vessels (n = 8), bilateral advanced tumor growth to the intrahepatic bile ducts (n = 3), infiltration of the complete liver hilum (n = 2), infiltration of the gallbladder (n = 1), and liver cirrhosis (n = 1). Patients with a T4 stadium were treated with curative intention twice, and in each case an R1 resection was achieved. Most patients with irresectable tumors can be suspected to have a T4 stadium as well. In a T3 situation (n = 6) we could establish five R0 resections and one R1 resection. Conclusion The limit of surgical resection for bile duct cancer is the advanced tumor stage (T stadium). While in a T3 stadium an R0 resection is possible in most cases, we were not able to perform an R0 resection in a T4 stadium. From our point of view, early T stadium cannot usually be estimated through expanded diagnostics but only through surgical exploration. PMID:26468314

  18. Ontogeny of the nasopalatine duct in primates.

    PubMed

    Shimp, Kristin L; Bhatnagar, Kunwar P; Bonar, Christopher J; Smith, Timothy D

    2003-09-01

    Ecological explanations have been put forward to account for the precocious or delayed development of patency in ducts leading to the vomeronasal organ (VNO) in certain mammals. Perinatal function may be related, in part, to the patency or fusion of the vomeronasal and nasopalatine (NPD) ducts. However, few studies have focused on NPD development in primates, which generally have a prolonged period of dependence during infancy. In this study we examined 24 prenatal primates and 13 neonatal primates, and a comparative sample of fetal mice and insectivores. In embryonic and early fetal Microcebus murinus, the NPD was completely fused, whereas in fetuses of later stages the duct was partially fused or completely patent. M. myoxinus of all stages demonstrated some degree of NPD fusion. In all other prenatal primates, the NPD was fused to some extent. Four prenatal insectivores (Tenrec ecaudatus) showed some degree of NPD fusion. In Mus musculus at 19 days gestation, the NPD was patent, although the anatomically separate VNO duct was fused. T. ecaudatus and most of the neonatal primates revealed complete NPD patency. An exception was Saguinus geoffroyi, which exhibited fusion of the NPD near the VNO opening. These observations may relate to differences in perinatal VNO function. The differences noted in our study suggest that M. murinus and M. myoxinus may differ in perinatal VNO functionality and perhaps in related behavior. Observations of neonatal primates suggest that NPD patency may be relatively common at birth and could serve other purposes in addition to being an access route for VNO stimuli.

  19. Idea Bank: Duct Tape Note Twister

    ERIC Educational Resources Information Center

    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…

  20. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    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.

  1. Sound attenuation of fiberglass lined ventilation ducts

    NASA Astrophysics Data System (ADS)

    Albright, Jacob

    Sound attenuation is a crucial part of designing any HVAC system. Most ventilation systems are designed to be in areas occupied by one or more persons. If these systems do not adequately attenuate the sound of the supply fan, compressor, or any other source of sound, the affected area could be subject to an array of problems ranging from an annoying hum to a deafening howl. The goals of this project are to quantify the sound attenuation properties of fiberglass duct liner and to perform a regression analysis to develop equations to predict insertion loss values for both rectangular and round duct liners. The first goal was accomplished via insertion loss testing. The tests performed conformed to the ASTM E477 standard. Using the insertion loss test data, regression equations were developed to predict insertion loss values for rectangular ducts ranging in size from 12-in x 18-in to 48-in x 48-in in lengths ranging from 3ft to 30ft. Regression equations were also developed to predict insertion loss values for round ducts ranging in diameters from 12-in to 48-in in lengths ranging from 3ft to 30ft.

  2. Sound in low velocity ventilation ducts

    NASA Astrophysics Data System (ADS)

    1982-07-01

    This Data Item is available as part of the ESDU Sub-series on Fluid Mechanics Internal Flow. Essential data for estimating the change in acoustical energy as sound propagates through a ventilating system is provided. From a knowledge of this sound energy, the sound pressure level which results on any room served by the system may be estimated. From consideration of the estimated sound pressure levels in the most sensitive areas of the building the amount of silencing required in the system to achieve acceptable sound levels can be assessed. Data are provided in either graphical or tabular form for the estimation of the attenuation of sound in ducts and duct fittings and for the estimation of the sound generated as air flows through standard duct fittings. A means of estimating the octave band sound pressure levels due to the air-conditioning system in a room is also given. Other factors which effect sound in ventilation ducts (e.g., breakout) are discussed.

  3. Common bile duct obstruction due to candidiasis.

    PubMed

    Domagk, D; Bisping, G; Poremba, C; Fegeler, W; Domschke, W; Menzel, J

    2001-04-01

    Biliary obstruction with its wide range of potential causes (e.g. neoplastic lesions, gallstones and inflammatory processes) is a common disease in gastroenterology. Although infections with Candida and other fungal species have increasingly been recognized in patients with certain predispositions, fungal involvement of the biliary tract is extremely rare. We report the case of a male patient with a past history of long-time mechanical ventilation and who was referred to our department with cholangitis. Endoscopic retrograde cholangio-pancreatography (ERCP) of the septic patient revealed a high-degree stenosis of the distal common bile duct with a prestenotic dilation which was strongly suspicious of an underlying malignancy. Control ERCP revealed a beads-like deformation of the intra- and extrahepatic bile duct system which was compatible with chronic secondary sclerosing cholangitis. Examining the bile duct system with a balloon catheter, a long tubular. filamentous structure with several branches at its sides could be extracted and was assessed histologically to be a Candida conglomerate. Candida colonization of the bile duct was confirmed by microbiological analysis of aspirated bile.

  4. Recent classifications of the common bile duct injury

    PubMed Central

    2014-01-01

    Laparoscopic cholecystectomy is now a gold standard treatment modality for gallstone diseases. However, the incidence rate of bile duct injury has not been changed for many years. From initial classification published by Bismuth, there have been many classifications of common bile duct injury. The initial classification, levels and types of bile duct injury, and currently combined vascular injuries are reviewed here. PMID:26155253

  5. Turbofan aft duct suppressor study program listing and user's guide

    NASA Technical Reports Server (NTRS)

    Joshi, M. C.; Kraft, R. E.

    1983-01-01

    A description of the structure of the Annular Flow Duct Program (AFDP) for the calculation of acoustic suppression due to treatment in a finite length annular duct carrying sheared flow is presented. Although most appropriate for engine exhaust ducts, this program can be used to study sound propagation in any duct that maintains annular geometry over a considerable length of the duct. The program is based on the modal analysis of sound propagation in ducts with axial segments of different wall impedances. For specified duct geometry, wall impedance, flow and acoustic conditions in the duct (including mode amplitude distribution of the source) and duct termination reflection characteristics, the program calculates the suppression due to the treatment in the duct. The presence of forward and backward traveling modes in the duct due to the reflection and redistribution of modes at segment interfaces and duct end terminations are taken into account in the calculations. The effects of thin wall boundary layers (with a linear or mean flow velocity profile) on the acoustic propagation are also included in the program. A functional description of the major subroutines is included and a sample run is provided with an explanation of the output.

  6. Combined Endoscopic and Laparoscopic Management of Postcholecystectomy Mirizzi Syndrome from a Remnant Cystic Duct Stone: Case Report and Review of the Literature.

    PubMed

    Amin, Arpit; Zhurov, Yuriy; Ibrahim, George; Maffei, Anthony; Giannone, Jonathan; Cerabona, Thomas; Kaul, Ashutosh

    2016-01-01

    Mirizzi syndrome has been defined in the literature as common bile duct obstruction resulting from calculi within Hartmann's pouch or cystic duct. We present a case of a 78-year-old female, who developed postcholecystectomy Mirizzi syndrome from a remnant cystic duct stone. Diagnosis of postcholecystectomy Mirizzi syndrome was made on endoscopic retrograde cholangiography (ERCP) performed postoperatively. The patient was treated with a novel strategy by combining advanced endoscopic and laparoscopic techniques in three stages as follows: Stage 1 (initial presentation): endoscopic sphincterotomy with common bile duct stent placement; Stage 2 (6 weeks after Stage 1): laparoscopic ultrasonography to locate the remnant cystic duct calculi followed by laparoscopic retrieval of the calculi and intracorporeal closure of cystic duct stump; Stage 3 (6 weeks after Stage 2): endoscopic removal of common bile duct stent along with performance of completion endoscopic retrograde cholangiogram. In addition, we have performed an extensive review of the various endoscopic and laparoscopic management techniques described in the literature for the treatment of postcholecystectomy syndrome occurring from retained cystic duct stones.

  7. Combined Endoscopic and Laparoscopic Management of Postcholecystectomy Mirizzi Syndrome from a Remnant Cystic Duct Stone: Case Report and Review of the Literature

    PubMed Central

    Amin, Arpit; Zhurov, Yuriy; Ibrahim, George; Maffei, Anthony; Giannone, Jonathan; Cerabona, Thomas; Kaul, Ashutosh

    2016-01-01

    Mirizzi syndrome has been defined in the literature as common bile duct obstruction resulting from calculi within Hartmann's pouch or cystic duct. We present a case of a 78-year-old female, who developed postcholecystectomy Mirizzi syndrome from a remnant cystic duct stone. Diagnosis of postcholecystectomy Mirizzi syndrome was made on endoscopic retrograde cholangiography (ERCP) performed postoperatively. The patient was treated with a novel strategy by combining advanced endoscopic and laparoscopic techniques in three stages as follows: Stage 1 (initial presentation): endoscopic sphincterotomy with common bile duct stent placement; Stage 2 (6 weeks after Stage 1): laparoscopic ultrasonography to locate the remnant cystic duct calculi followed by laparoscopic retrieval of the calculi and intracorporeal closure of cystic duct stump; Stage 3 (6 weeks after Stage 2): endoscopic removal of common bile duct stent along with performance of completion endoscopic retrograde cholangiogram. In addition, we have performed an extensive review of the various endoscopic and laparoscopic management techniques described in the literature for the treatment of postcholecystectomy syndrome occurring from retained cystic duct stones. PMID:27047698

  8. Advanced Strategy Guideline. Air Distribution Basics and Duct Design

    SciTech Connect

    Burdick, Arlan

    2011-12-01

    This report discusses considerations for designing an air distribution system for an energy efficient house that requires less air volume to condition the space. Considering the HVAC system early in the design process will allow adequate space for equipment and ductwork and can result in cost savings.

  9. Heat Transfer in a Superelliptic Transition Duct

    NASA Technical Reports Server (NTRS)

    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.

  10. Experimental testing and computational modeling of flat oval duct deflection

    SciTech Connect

    Smolinski, P.J.; Palmer, G.S.

    1998-10-01

    The deflection characteristics of spiral seam flat oval HVAC duct are examined in this study, and the effects of duct size, wall thickness, and the size spacing, and type of external reinforcement on the duct deformation are investigated. A duct test setup and a deflection measurement frame were developed for measuring the deformation of flat oval duct, and experimental testing was performed on a variety of duct configurations to measure the duct deflections at various positive and negative internal pressures. Finite element computer models of the ducts were developed to predict the deflections. The correlation between the predictions of the computer model and the data from the experimental testing is highly variable with differences ranging from a few percent to several hundred percent. In general, it was found that there was closer agreement between the finite element results and the experimental measurements for smaller duct and at locations of type 2 external reinforcements. This may be due to the fact that the finite element model assumed the idealized flat oval shape and this shape was better matched by smaller ducts and near the external reinforcement. It was also found that in some cases, unreinforced duct could achieve higher pressures than type 1 reinforced duct before exceeding the deflection limits. Sources of error include the uneven surface of the mastic in the measurement of the duct joint deflection and the variance of the actual duct shape from the idealized shape used in the finite element model. This study did not examine the variability of the experimental results due to differences in duct shape or manufacture.

  11. Particle deposition in ventilation ducts: Connectors, bends anddeveloping flow

    SciTech Connect

    Sippola, Mark R.; Nazaroff, William W.

    2004-03-01

    In ventilation duct flow the turbulent flow profile is commonly disturbed or not fully developed and these conditions are likely to influence particle deposition to duct surfaces. Particle deposition rates at eight S-connectors, in two 90{sup o} duct bends and in two ducts where the turbulent flow profile was not fully developed were measured in a laboratory duct system with both galvanized steel and internally insulated ducts with hydraulic diameters of 15.2 cm. In the steel duct system, experiments with nominal particle diameters of 1, 3, 5, 9 and 16 {micro}m were conducted at each of three nominal air speeds: 2.2, 5.3 and 9.0 m/s. In the insulated duct system, deposition of particles with nominal diameters of 1, 3, 5, 8 and 13 {micro}m was measured at nominal air speeds of 2.2, 5.3 and 8.8 m/s. Fluorescent techniques were used to directly measure the deposition velocities of monodisperse fluorescent particles to duct surfaces. Deposition at S-connectors, in bends and in straight ducts with developing turbulence was often greater than deposition in straight ducts with fully developed turbulence for equal particle sizes, air speeds and duct surface orientations. Deposition rates at all locations were found to increase with an increase in particle size or air speed. High deposition rates at S-connectors resulted from impaction and these rates were nearly independent of the orientation of the S-connector. Deposition rates in the two 90{sup o} bends differed by more than an order of magnitude in some cases, probably because of the difference in turbulence conditions at the bend inlets. In straight steel ducts where the turbulent flow profile was developing, the deposition enhancement relative to fully developed turbulence generally increased with air speed and decreased with downstream distance from the duct inlet. This enhancement was greater at the duct ceiling and wall than at the duct floor. In insulated ducts, deposition enhancement was less pronounced overall

  12. Obstructing pseudocyst of the duct of Santorini in pancreas divisum.

    PubMed

    Browder, W; Gravois, E; Vega, P; Ertan, A

    1987-03-01

    Pancreas divisum is a pancreatic duct anomaly that occurs due to failure of fusion of the dorsal and ventral ducts. While recognition of this anomaly is increasing due to more aggressive endoscopic retrograde cholangiopancreatography, its significance remains unclear. A patient with chronic pancreatitis and a history of alcohol abuse was noted to have pancreas divisum. At surgical exploration, intraoperative pancreatography revealed an obstructing pseudocyst of the duct of Santorini. Extended sphincteroplasty and cystduodenostomy as well as Roux-en-Y pancreatojejunostomy were necessary to insure adequate accessory duct drainage. Surgical therapy of pancreas divisum in chronic pancreatitis should be designed to correct existing pancreatic duct obstruction.

  13. Transition duct with divided upstream and downstream portions

    SciTech Connect

    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.

  14. Acoustic radiation from lined, unflanged ducts: Acoustic source distribution program

    NASA Technical Reports Server (NTRS)

    Beckemeyer, R. J.; Sawdy, D. T.

    1971-01-01

    An acoustic radiation analysis was developed to predict the far-field characteristics of fan noise radiated from an acoustically lined unflanged duct. This analysis is comprised of three modular digital computer programs which together provide a capability of accounting for the impedance mismatch at the duct exit plane. Admissible duct configurations include circular or annular, with or without an extended centerbody. This variation in duct configurations provides a capability of modeling inlet and fan duct noise radiation. The computer programs are described in detail.

  15. Endoscopic Ultrasound (EUS)-Guided Pancreatic Duct Drainage: The Basics of When and How to Perform EUS-Guided Pancreatic Duct Interventions

    PubMed Central

    Chapman, Christopher G.; Waxman, Irving; Siddiqui, Uzma D.

    2016-01-01

    Despite the advances in endoscopy, endoscopic ultrasound-guided pancreatic duct drainage (EUS-PDD) remains a technically challenging procedure. Technical success rates are greater than 70%; however, the average rate of adverse events is nearly 20%, which increases to 55% when stent migration is included. Until recently, a significant difficulty with this technique was the absence of dedicated devices. Proper patient selection is of utmost importance, and EUS-PDD should be reserved for patients who have failed endoscopic retrograde pancreatography. Furthermore, EUS-PDD must be performed by experienced endoscopists who are familiar with the technique. The most common indications include chronic pancreatitis induced strictures and stones, disconnected pancreatic ducts, inaccessible ampulla, and post-surgical altered anatomy. This manuscript will review the accessories used, techniques employed, and published literature reporting outcomes as well as adverse events regarding EUS-PDD. PMID:27012290

  16. Acoustic propagation in curved ducts with extended reacting wall treatment

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.

    1989-01-01

    A finite-element Galerkin formulation was employed to study the attenuation of acoustic waves propagating in two-dimensional S-curved ducts with absorbing walls without a mean flow. The reflection and transmission at the entrance and the exit of a curved duct were determined by coupling the finite-element solutions in the curved duct to the eigenfunctions of an infinite, uniform, hard wall duct. In the frequency range where the duct height and acoustic wave length are nearly equal, the effects of duct length, curvature (duct offset) and absorber thickness were examined. For a given offset in the curved duct, the length of the S-duct was found to significantly affect both the absorptive and reflective characteristics of the duct. A means of reducing the number of elements in the absorber region was also presented. In addition, for a curved duct, power attenuation contours were examined to determine conditions for maximum acoustic power absorption. Again, wall curvature was found to significantly effect the optimization process.

  17. Winglet and long duct nacelle aerodynamic development for DC-10 derivatives

    NASA Technical Reports Server (NTRS)

    Taylor, A. B.

    1978-01-01

    Advanced technology for application to the Douglas DC-10 transport is discussed. Results of wind tunnel tests indicate that the winglet offers substantial cruise drag reduction with less wing root bending moment penalty than a wing-tip extension of the same effectiveness and that the long duct nacelle offers substantial drag reduction potential as a result of aerodynamic and propulsion improvements. The aerodynamic design and test of the nacelle and pylon installation are described.

  18. The Reduction of Ducted Fan Engine Noise Via a Boundary Integral Equation Method

    NASA Technical Reports Server (NTRS)

    Tweed, John

    2000-01-01

    Engineering studies for reducing ducted fan engine noise were conducted using the noise prediction code TBIEM3D. To conduct parametric noise reduction calculations, it was necessary to advance certain theoretical and computational aspects of the boundary integral equation method (BIEM) described in and implemented in TBIEM3D. Also, enhancements and upgrades to TBIEM3D were made for facilitating the code's use in this research and by the aeroacoustics engineering community.

  19. Coupled parametric design of flow control and duct shape

    NASA Technical Reports Server (NTRS)

    Florea, Razvan (Inventor); Bertuccioli, Luca (Inventor)

    2009-01-01

    A method for designing gas turbine engine components using a coupled parametric analysis of part geometry and flow control is disclosed. Included are the steps of parametrically defining the geometry of the duct wall shape, parametrically defining one or more flow control actuators in the duct wall, measuring a plurality of performance parameters or metrics (e.g., flow characteristics) of the duct and comparing the results of the measurement with desired or target parameters, and selecting the optimal duct geometry and flow control for at least a portion of the duct, the selection process including evaluating the plurality of performance metrics in a pareto analysis. The use of this method in the design of inter-turbine transition ducts, serpentine ducts, inlets, diffusers, and similar components provides a design which reduces pressure losses and flow profile distortions.

  20. SNM holdup assessment of Los Alamos exhaust ducts. Final report

    SciTech Connect

    Marshall, R.S.

    1994-02-01

    Fissile material holdup in glovebox and fume hood exhaust ducting has been quantified for all Los Alamos duct systems. Gamma-based, nondestructive measurements were used to quantify holdup. The measurements were performed during three measurement campaigns. The first campaign, Phase I, provided foot-by-foot, semiquantitative measurement data on all ducting. These data were used to identify ducting that required more accurate (quantitative) measurement. Of the 280 duct systems receiving Phase I measurements, 262 indicated less than 50 g of fissile holdup and 19 indicated fissile holdup of 50 or more grams. Seven duct systems were measured in a second campaign, called Series 1, Phase II. Holdup estimates on these ducts ranged from 421 g of {sup 235}U in a duct servicing a shut-down uranium-machining facility to 39 g of {sup 239}Pu in a duct servicing an active plutonium-processing facility. Measurements performed in the second campaign proved excessively laborious, so a third campaign was initiated that used more efficient instrumentation at some sacrifice in measurement quality. Holdup estimates for the 12 duct systems measured during this third campaign ranged from 70 g of {sup 235}U in a duct servicing analytical laboratories to 1 g of {sup 235}U and 1 g of {sup 239}Pu in a duct carrying exhaust air to a remote filter building. These quantitative holdup estimates support the conclusion made at the completion of the Phase I measurements that only ducts servicing shut-down uranium operations contain about 400 g of fissile holdup. No ventilation ducts at Los Alamos contain sufficient fissile material holdup to present a criticality safety concern.

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

    NASA Technical Reports Server (NTRS)

    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.

  2. A straightforward method for wall impedance eduction in a flow duct.

    PubMed

    Jing, Xiaodong; Peng, Sen; Sun, Xiaofeng

    2008-07-01

    The development of the advanced liner technology for aeroengine noise control necessitates the impedance measurement method under realistic flow conditions. Currently, the methods for this need are mainly based on the inverse impedance eduction principle, confronting with the problems of initial guess, high computation cost, and low convergence. In view of this, a new strategy is developed that straightforwardly educes the impedance from the sound pressure information measured on the duct wall opposing to the test acoustic liner embedded in a flow duct. Here, the key insight is that the modal nature of the duct acoustic field renders a summed-exponential representation of the measured sound pressure; thus, the characterizing axial wave number can be readily extracted by means of Prony's method, and further the unknown impedance is calculated from the eigenvalue and dispersion relations based on the classical mode-decomposition analysis. This straightforward method is simple in its basic principle but remarkably has the advantages of ultimately overcoming the drawbacks inherent to the inverse methods, incorporating the realistic multimode nonprogressive wave effects, high computational efficiency, possibly reducing the measurement points, and even avoiding the necessity of the duct exit impedance that bothers perhaps all the existing waveguide methods.

  3. Advanced ramjet concepts program

    NASA Technical Reports Server (NTRS)

    Leingang, J. L.

    1992-01-01

    Uniquely advantageous features, on both the performance and weight sides of the ledger, can be achieved through synergistic design integration of airbreathing and rocket technologies in the development of advanced orbital space transport propulsion systems of the combined cycle type. In the context of well understood advanced airbreathing and liquid rocket propulsion principles and practices, this precept of synergism is advanced mainly through six rather specific examples. These range from the detailed component level to the overall vehicle system level as follows: using jet compression; achieving a high area ratio rocket nozzle; ameliorating gas generator cycle rocket system deficiencies; using the in-duct special rocket thrust chamber assembly as the principal scramjet fuel injection operation; using the unstowed, covered fan as a duct closure for effecting high area ratio rocket mode operation; and creating a unique airbreathing rocket system via the onboard, cryogenic hydrogen induced air liquefaction process.

  4. Optimization of the mechanical performance of a two-duct semicircular duct system--part 2: excitation of endolymph movements.

    PubMed

    Muller, M; Verhagen, J H G

    2002-06-21

    The endolymph flow inside the semicircular ducts is analytically investigated by considering a system of two hydrodynamically interconnected ducts. Rotation of this system adds an amount of motion (momentum) to parts of it. This results in an endolymph flow in generally all vestibular parts. The "external impulses" are the impulses which emerge by rotation of exclusively a particular vestibular part. The real impulses can be calculated from a set of equations which contain the external impulses. Analytical expressions are derived for the initial velocities in the ducts and for the maximum endolymph displacements. These formulae contain the external impulses and the ratios of: (1) the radii of crus commune and ducts (gamma), (2) the lengths of crus commune and ducts (lambda). It was proven that an interconnected system composed of two ducts, and also a system composed of two such semicircular duct systems, behaves as a pure rotation transducer (like a single duct does), also when it is rotated excentrically. Duct systems with polygonal and circular geometries were used to evaluate whether an optimal value of lambda would exist (gamma was already considered elsewhere). Optimum values of lambda in a range of about 0.10-0.52 were found. This rather wide range of values agrees with values from measurements. Optimization of an interconnected duct system appeared to be equal to optimization of a system composed of separate ducts. PMID:12151259

  5. Impact fracture behavior of HT9 duct

    SciTech Connect

    Huang, F.H.; Gelles, D.S.

    1994-07-01

    Ferritic alloys are known to undergo a ductile-brittle transition as the test temperature is decreased. This inherent problem has limited their applications to reactor component materials subjected to low neutron exposures. However, the excellent resistance to void swelling exhibited by these alloys has led to choosing the materials as candidate materials for fast and fusion reactor applications. Despite the ductile-brittle transition problem, results show that the materials exhibit superior resistance to fracture under very high neutron fluences at irradiation temperatures above 380{degrees}C. Impact testing on FFTF duct sections of HT9 indicates that HT9 ducts have adequate fracture toughness at much higher temperatures for handling operations at room temperature and refueling operations.

  6. [Neuroma of the common bile duct].

    PubMed

    Saint-Paul, M C; Benchimol, D; Dumas, R; Michiels, J F; Hofman, P; van den Broucke, X; Richelme, H; Fuzibet, J; Loubière, R

    1993-01-01

    After a surgical operation on the biliary tract, stenoses can occur, most of the time due to fibrotic lesions, and more rarely due to granulomas or traumatic neuromas. The latter generally develop on the cystic stump after a cholecystectomy. The occurrence of a traumatic neuroma on the common bile duct is much more rarely described. We report the case of a 64 year-old man presenting, four years after a surgical removal of the gallbladder, with a cholangitis, due to neuroma located on the choledochus. He was treated by surgical resection of the common bile-duct at the site of the stenotic zone, and choledocojejunal anastomosis; post-operative course was satisfactory.

  7. Intrahepatic Duct Stones Harboring Ascariasis Ova

    PubMed Central

    Lee, Chen-Fang; Lee, Wei-Chen; Wu, Ren-Chin; Chen, Tse-Ching

    2016-01-01

    Abstract Ascariasis lumbricoides is one of the most common helminthic infestations in humans. Despite the fact that the prevalence of ascariasis in developed countries has been decreasing, biliary ascariasis can cause serious complications, such as acute cholangitis, pancreatitis, and liver abscess. Here we presented a rare ascariasis-related complication—hepatolithiasis. A 60-year-old female patient had symptoms of recurrent cholangitis. Abdominal computed tomography scan revealed left intrahepatic duct stones with left liver lobe atrophy. Endoscopic retrograde cholangiopancreatography was performed, but the stones could not be removed due to left main intrahepatic duct stenosis. The patient was treated with left hemi-hepatectomy. Unexpectedly, Ascaris ova were found on the histopathological examination. She received antihelminthic therapy orally and was on regular follow-up without any complications. Our study indicates that clinicians should be aware of biliary ascariasis in patients with hepatolithiasis, though not living in endemic areas. PMID:27015193

  8. Theoretical analysis of HVAC duct hanger systems

    NASA Technical Reports Server (NTRS)

    Miller, R. D.

    1987-01-01

    Several methods are presented which, together, may be used in the analysis of duct hanger systems over a wide range of frequencies. The finite element method (FEM) and component mode synthesis (CMS) method are used for low- to mid-frequency range computations and have been shown to yield reasonably close results. The statistical energy analysis (SEA) method yields predictions which agree with the CMS results for the 800 to 1000 Hz range provided that a sufficient number of modes participate. The CMS approach has been shown to yield valuable insight into the mid-frequency range of the analysis. It has been demonstrated that it is possible to conduct an analysis of a duct/hanger system in a cost-effective way for a wide frequency range, using several methods which overlap for several frequency bands.

  9. [Ultrasound of gallbladder and bile duct].

    PubMed

    Segura Grau, A; Joleini, S; Díaz Rodríguez, N; Segura Cabral, J M

    2016-01-01

    The cystic nature of the gallbladder and bile duct when dilated, and the advantages of ultrasound as a quick, reproducible, convenient, cheap and low risk technique, with a high sensitivity and specificity, make it the most eligible technique in biliary pathology studies. Ultrasound has become a valuable tool for doctors studying biliary pathology and its complications, from abnormal liver function results, right upper quadrant pain, or jaundice, to cholelithiasis, cholecystitis, or suspicion of biliary tumors.

  10. Acoustic-Liner Admittance in a Duct

    NASA Technical Reports Server (NTRS)

    Watson, W. R.

    1986-01-01

    Method calculates admittance from easily obtainable values. New method for calculating acoustic-liner admittance in rectangular duct with grazing flow based on finite-element discretization of acoustic field and reposing of unknown admittance value as linear eigenvalue problem on admittance value. Problem solved by Gaussian elimination. Unlike existing methods, present method extendable to mean flows with two-dimensional boundary layers as well. In presence of shear, results of method compared well with results of Runge-Kutta integration technique.

  11. Autoignitions and detonations in engines and ducts.

    PubMed

    Bradley, Derek

    2012-02-13

    The origins of autoignition at hot spots are analysed and the pressure pulses that arise from them are related to knock in gasoline engines and to developing detonations in ducts. In controlled autoignition engines, autoignition is benign with little knock. There are several modes of autoignition and the existence of an operational peninsula, within which detonations can develop at a hot spot, helps to explain the performance of various engines. Earlier studies by Urtiew and Oppenheim of the development of autoignitions and detonations ahead of a deflagration in ducts are interpreted further, using a simple one-dimensional theory of the generation of shock waves ahead of a turbulent flame. The theory is able to indicate entry into the domain of autoignition in an 'explosion in the explosion'. Importantly, it shows the influence of the turbulent burning velocity, and particularly its maximum attainable value, upon autoignition. This value is governed by localized flame extinctions for both turbulent and laminar flames. The theory cannot show any details of the transition to a detonation, but regimes of eventually stable or unstable detonations can be identified on the operational peninsula. Both regimes exhibit transverse waves, triple points and a cellular structure. In the case of unstable detonations, transverse waves are essential to the continuing propagation. For hazard assessment, more needs to be known about the survival, or otherwise, of detonations that emerge from a duct into the same mixture at atmospheric pressure. PMID:22213665

  12. Autoignitions and detonations in engines and ducts.

    PubMed

    Bradley, Derek

    2012-02-13

    The origins of autoignition at hot spots are analysed and the pressure pulses that arise from them are related to knock in gasoline engines and to developing detonations in ducts. In controlled autoignition engines, autoignition is benign with little knock. There are several modes of autoignition and the existence of an operational peninsula, within which detonations can develop at a hot spot, helps to explain the performance of various engines. Earlier studies by Urtiew and Oppenheim of the development of autoignitions and detonations ahead of a deflagration in ducts are interpreted further, using a simple one-dimensional theory of the generation of shock waves ahead of a turbulent flame. The theory is able to indicate entry into the domain of autoignition in an 'explosion in the explosion'. Importantly, it shows the influence of the turbulent burning velocity, and particularly its maximum attainable value, upon autoignition. This value is governed by localized flame extinctions for both turbulent and laminar flames. The theory cannot show any details of the transition to a detonation, but regimes of eventually stable or unstable detonations can be identified on the operational peninsula. Both regimes exhibit transverse waves, triple points and a cellular structure. In the case of unstable detonations, transverse waves are essential to the continuing propagation. For hazard assessment, more needs to be known about the survival, or otherwise, of detonations that emerge from a duct into the same mixture at atmospheric pressure.

  13. Radiative interactions in laminar duct flows

    NASA Technical Reports Server (NTRS)

    Trivedi, P. A.; Tiwari, S. N.

    1990-01-01

    Analyses and numerical procedures are presented for infrared radiative energy transfer in gases when other modes of energy transfer occur simultaneously. Two types of geometries are considered, a parallel plate duct and a circular duct. Fully developed laminar incompressible flows of absorbing-emitting species in black surfaced ducts are considered under the conditions of uniform wall heat flux. The participating species considered are OH, CO, CO2, and H2O. Nongray as well as gray formulations are developed for both geometries. Appropriate limiting solutions of the governing equations are obtained and conduction-radiation interaction parameters are evaluated. Tien and Lowder's wide band model correlation was used in nongray formulation. Numerical procedures are presented to solve the integro-differential equations for both geometries. The range of physical variables considered are 300 to 2000 K for temperature, 0.1 to 100.0 atm for pressure, and 0.1 to 100 cm spacings between plates/radius of the tube. An extensive parametric study based on nongray formulation is presented. Results obtained for different flow conditions indicate that the radiative interactions can be quite significant in fully developed incompressible flows.

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

    PubMed

    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

  15. Accessory Pancreatic Duct Patterns and Their Clinical Implications

    PubMed Central

    Prasanna, Lokadolalu Chandracharya; Rajagopal, KV; Thomas, Huban R

    2015-01-01

    Context and Objective: Accessory pancreatic duct (APD) designed to reduce the pressure of major pancreatic duct by forming a secondary drainage channel. Few studies have mentioned the variant types of accessory ducts and their mode of formation, some of these have a clear clinical significance. Present study is aimed to evaluate the possible variations in the APD and its terminations. Materials and Methods: Forty formalin fixed adult human pancreas with duodenum in situ specimens were studied by injecting 1% aqueous eosin, followed by piece meal dissection of the head of the pancreas from posterior surface. Formation, tributaries, relations, and the termination of the accessory pancreatic duct were noted and photographed. Results: Accessory ducts revealed 50% belonged to long type, 22.5% were of short and ansa pancreatica type each, and embryonic type of duct pattern was seen in 5% specimens. 75% of long type ducts showed positive patency with eosin dye, followed by ansa type (44.4%), and least patency was found in short type (22.2%). With regard to the patency of the accessory pancreatic ducts towards their termination, we found 52.5% of the accessory ducts and 5% of the embryonic type pancreatic ducts were patent and in 42.5% of the specimen the ducts were obliterated. In 85% of specimens the minor duodenal papillae was anterosuperior to the major papilla and superior to the major papillae in 10% of the cases, and in 5% minor papillae was absent. The average distance between the two papillae was 2.35 cm. Conclusion: The knowledge of the complex anatomical relations of the gland with its duct, duodenum and bile ducts are essential for the surgeons and sinologists to plan and perform both the diagnostic as well as therapeutic procedures effectively. PMID:25954609

  16. Optimizing Electrospray Interfaces Using Slowly Diverging Conical Duct (ConDuct) Electrodes

    PubMed Central

    Krutchinsky, Andrew N.; Padovan, Júlio C.; Cohen, Herbert; Chait, Brian T.

    2015-01-01

    We demonstrate that the efficiency of ion transmission from atmosphere to vacuum through stainless steel electrodes that contain slowly divergent conical duct (ConDuct) channels can be close to 100%. Here, we explore the properties of 2.5 cm long electrodes with angles of divergence of 0°, 1°, 2°, 3°, 5°, 8°, 13°, and 21°, respectively. The ion transmission efficiency was observed to jump from 10–20% for the 0° (straight) channels to 90–95% for channels with an angle of divergence as small as 1°. Furthermore, the 2–3° ConDuct electrodes produced extraordinarily low divergence ion beams that propagated in a laser-like fashion over long distances in vacuum. To take advantage of these newly discovered properties, we constructed a novel atmosphere-to-vacuum ion interface utilizing a 2° ConDuct as an inlet electrode and compared its ion transmission efficiency with that of the interface used in the commercial (Thermo) Velos Orbitrap and Q Exactive mass spectrometers. We observed that the ConDuct interface transmitted up to 17 times more ions than the commercial reference interface and also yielded improved signal-to-noise mass spectra of peptides. We infer from these results that the performance of many current atmosphere-tovacuum interfaces utilizing metal capillaries can be substantially improved by replacing them with 1° or 2° metal ConDuct electrodes, which should preserve the convenience of supplying ion desolvation energy by heating the electrode while greatly increasing the efficiency of ion transmission into the mass spectrometer. PMID:25667060

  17. Hydrodynamic Modeling, Optimization and Performance Assessment for Ducted and Non-ducted Tidal Turbines

    NASA Astrophysics Data System (ADS)

    Shives, Michael Robert

    This thesis examines methods for designing and analyzing kinetic turbines based on blade element momentum (BEM) theory and computational fluid dynamics (CFD). The underlying goal of the work was to assess the potential augmentation of power production associated with enclosing the turbine in an expanding duct. Thus, a comparison of the potential performance of ducted and non-ducted turbines was carried out. This required defining optimal turbine performance for both concepts. BEM is the typical tool used for turbine optimization and is very well established in the context of wind turbine design. BEM was suitable for conventional turbines, but could not account for the influence of ducts, and no established methodology for designing ducted turbines could be found in the literature. Thus, methods were established to design and analyze ducted turbines based on an extended version of BEM (with CFD-derived coefficients), and based on CFD simulation. Additional complications arise in designing tidal turbines because traditional techniques for kinetic turbine design have been established for wind turbines, which are similar in their principle of operation but are driven by flows with inherently different boundary conditions than tidal currents. The major difference is that tidal flows are bounded by the ocean floor, the water surface and channel walls. Thus, analytical and CFD-based methods were established to account for the effects of these boundaries (called blockage effects) on the optimal design and performance of turbines. Additionally, tidal flows are driven by changes in the water surface height in the ocean and their velocity is limited by viscous effects. Turbines introduced into a tidal flow increase the total drag in the system and reduce the total flow in a region (e.g. a tidal channel). An analytical method to account for this was taken from the field of tidal resource assessment, and along with the methods to account for ducts and blockage effects, was

  18. Aberrant bile ducts, 'remnant surface bile ducts,' and peribiliary glands: descriptive anatomy, historical nomenclature, and surgical implications.

    PubMed

    El Gharbawy, Ramadan M; Skandalakis, Lee J; Heffron, Thomas G; Skandalakis, John E

    2011-05-01

    The term "aberrant bile ducts" has been used to designate three heterogeneous groups of biliary structures: (1) bile ducts degenerating or disappearing (unknown etiology, diverse locations); (2) curious biliary structures in the transverse fissure; and (3) aberrant right bile ducts draining directly into the common hepatic duct. We report our observations on these three groups. Twenty-nine fresh human livers of stillborns and adults were injected differentially with colored latex and dissected. Adult livers showed portal venous and hepatic arterial branches, and bile ducts not associated with parenchyma, subjacent to and firmly adherent with the liver capsule: elements of ramifications of normal sheaths were present on the liver's surface. These ramifications, having lost parenchyma associated with them, then sequentially lost their portal branches, bile ducts and arterial branches. This process affected the ramifications of the sheaths in the left triangular ligament, adjacent to the inferior vena cava, in the gallbladder bed and anywhere else on the liver's surface and resulted in the presence of bile ducts accompanied by portal venous and/or hepatic arterial branches and not associated with parenchyma for a period of time. This first group represented normal bile ducts that do not meet the criteria of aberration and could be appropriately designated "remnant surface bile ducts." Such changes were not found in the transverse fissures and review of the literature revealed that the curious biliary structures are the microscopic peribiliary glands. The third group met the criteria of aberration and the anatomy of a representative duct is described.

  19. Optimization of the mechanical performance of a two-duct semicircular duct system--part 3: the positioning of the ducts in the head.

    PubMed

    Muller, M; Verhagen, J H G

    2002-06-21

    In the majority of vertebrates, the horizontal duct of the vestibular system lies approximately in the yawing plane of the head. The positioning of the vertical ducts, however, is not in the pitch- and roll planes but the vertical ducts generally lie under an angle of about 30-45 degrees relative to the medial plane. Using the equations for a hydrodynamically interconnected two-duct system, optimal positions of the vertical and horizontal ducts in different vertebrate groups can be derived. It was stated that the mean response of the vertical ducts should be optimized. This leads to a symmetrical positioning of the vertical ducts with respect to the medial plane. In all observed vertebrate groups, a solution of mu =(pi-alpha)/2 is found (mu is the angle of the vertical ducts relative to the medial plane, alpha is the angle between the vertical duct planes). For alpha=90 degrees, this provides an equal sensitivity for pitch- and roll- movements. For alpha>90 degrees, a larger sensitivity for pitch movements is obtained, at the expense of a lower sensitivity for roll movements. It is argued that the angle alpha between the vertical ducts may vary from 90 to 120 degrees. In most vertebrates, the centre of mass is stabilized by e.g. fins, tri- or quadrupedal stability, a crawling body or upside-down resting positions (e.g. bats). Birds are generally biped, so in walking they are also rather sensitive to roll. These features are related to labyrinth positioning in the head. PMID:12151260

  20. An unsteady Euler scheme for the analysis of ducted propellers

    NASA Technical Reports Server (NTRS)

    Srivastava, R.

    1992-01-01

    An efficient unsteady solution procedure has been developed for analyzing inviscid unsteady flow past ducted propeller configurations. This scheme is first order accurate in time and second order accurate in space. The solution procedure has been applied to a ducted propeller consisting of an 8-bladed SR7 propeller with a duct of NACA 0003 airfoil cross section around it, operating in a steady axisymmetric flowfield. The variation of elemental blade loading with radius, compares well with other published numerical results.

  1. Flexible metallic seal for transition duct in turbine system

    SciTech Connect

    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.

  2. BTS Fact Sheet: Improving the efficiency of your duct system

    SciTech Connect

    BNL

    1999-12-28

    The duct system, used in air heating and air cooling your home, is a collection of tubes that distributes the heated or cooled air to the various rooms. The duct system can have an important effect on health of the occupants through the distribution of indoor air pollution. Changes and repairs to a duct system should always be performed by a qualified professional. This brochure is meant to help you understand the problems that can affect the duct system and how you can save money, improve comfort, and protect against potential health hazards.

  3. Thermal performance of residential duct systems in basements

    SciTech Connect

    Treidler, B.; Modera, M.

    1994-02-01

    There are many unanswered questions about the typical effects of duct system operation on the infiltration rates and energy usage of single- family residences with HVAC systems in their basements. In this paper, results from preliminary field studies and computer simulations are used to examine the potential for improvements in efficiency of air distribution systems in such houses. The field studies comprise thermal and flow measurements on four houses in Maryland. The houses were found to have significant envelope leakage, duct leakage, and duct conduction losses. Simulations of a basement house, the characteristics of which were chosen from the measured houses, were performed to assess the energy savings potential for basement house. The simulations estimate that a nine percent reduction in space conditioning energy use is obtained by sealing eighty percent of the duct leaks and insulating ducts to an R-value of 0.88 {degree}C{center_dot}m{sup 2}/W (5{degree}F{center_dot}ft{sup 2}{center_dot}h/BTU) where they are exposed in the basement. To determine the maximum possible reduction m energy use, simulations were run with all ducts insulated to 17.6 {degree}C{center_dot}m{sup 2}/W (100 {degree}F{center_dot}ft{sup 2}{center_dot}h/BTU) and with no duct leakage. A reduction of energy use by 14% is obtained by using perfect ducts instead of nominal ducts.

  4. Convolution seal for transition duct in turbine system

    SciTech Connect

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

    2015-03-10

    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 convolution seal contacting the interface member to provide a seal between the interface member and the turbine section.

  5. Analysis of nephric duct specification in the avian embryo

    PubMed Central

    Attia, Lital; Yelin, Ronit; Schultheiss, Thomas M.

    2012-01-01

    Vertebrate kidney tissue exhibits variable morphology that in general increases in complexity when moving from anterior to posterior along the body axis. The nephric duct, a simple unbranched epithelial tube, is derived in the avian embryo from a rudiment located in the anterior intermediate mesoderm (IM) adjacent to somites 8 to 10. Using quail-chick chimeric embryos, the current study finds that competence to form nephric duct is fixed when IM precursor cells are still located in the primitive streak, significantly before the onset of duct differentiation. In the primitive streak, expression of the gene HoxB4 is associated with prospective duct IM, whereas expression of the more posterior Hox gene HoxA6 is associated with more posterior, non-duct-forming IM. Misexpression of HoxA6, but not of HoxB4, in prospective duct-forming regions of the IM resulted in repression of duct formation, suggesting a mechanism for the restriction of duct formation to the anterior-most IM. The results are discussed with respect to their implications for anterior-posterior patterning of kidney tissue and of mesoderm in general, and for the loss of duct-forming ability in more posterior regions of the IM that has occurred during vertebrate evolution. PMID:23034630

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

    SciTech Connect

    Not Available

    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)

  7. Leaf seal for transition duct in turbine system

    SciTech Connect

    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.

  8. The Advanced Noise Control Fan Baseline Measurements

    NASA Technical Reports Server (NTRS)

    McAllister, Joseph; Loew, Raymond A.; Lauer, Joel T.; Stuliff, Daniel L.

    2009-01-01

    The NASA Glenn Research Center s (NASA Glenn) Advanced Noise Control Fan (ANCF) was developed in the early 1990s to provide a convenient test bed to measure and understand fan-generated acoustics, duct propagation, and radiation to the farfield. As part of a complete upgrade, current baseline and acoustic measurements were documented. Extensive in-duct, farfield acoustic, and flow field measurements are reported. This is a follow-on paper to documenting the operating description of the ANCF.

  9. Recent advances in active noise control

    NASA Astrophysics Data System (ADS)

    Guicking, D.

    Advances in the field of active noise control over the last few years are reviewed. Some commercially available products and their technical applications are described, with particular attention given to broadband duct noise silencers, broadband active headphones, waveform synthesis, and LMS controllers. Recent theoretical and experimental research activities are then reviewed. These activities are concerned with duct noise, structural sound, interior spaces, algorithms, echo cancellation, and miscellaneous applications.

  10. Reducing Thermal Losses and Gains With Buried and Encapsulated Ducts in Hot-Humid Climates

    SciTech Connect

    Shapiro, C.; Magee, A.; Zoeller, W.

    2013-02-01

    The Consortium for Advanced Residential Buildings (CARB) monitored three houses in Jacksonville, FL, to investigate the effectiveness of encapsulated and encapsulated/buried ducts in reducing thermal losses and gains from ductwork in unconditioned attics. Burying ductwork beneath loose-fill insulation has been identified as an effective method of reducing thermal losses and gains from ductwork in dry climates, but it is not applicable in humid climates where condensation may occur on the outside of the duct jacket. By encapsulating the ductwork in closed cell polyurethane foam (ccSPF) before burial beneath loose-fill mineral fiber insulation, the condensation potential may be reduced while increasing the R-value of the ductwork.

  11. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    Wortman, A.; Othmer, P.; Rostafinski, W.

    1992-01-01

    An experimental demonstration is presented for the generation of detonation waves that move periodically across high speed channel flow; these waves can compress the outflow from a low pressure compressor, and thereby both reduce the compressor requirements associated with conventional gas turbines and enhance 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 result is a Humphrey cycle augmenting the basic Brayton-cycle gas turbine. Attention is presently given to results from an experimental detonation duct.

  12. Radiation of sound from unflanged cylindrical ducts

    NASA Technical Reports Server (NTRS)

    Hartharan, S. L.; Bayliss, A.

    1983-01-01

    Calculations of sound radiated from unflanged cylindrical ducts are presented. The numerical simulation models the problem of an aero-engine inlet. The time dependent linearized Euler equations are solved from a state of rest until a harmonic solution is attained. A fourth order accurate finite difference scheme is used and solutions are obtained from a fully vectorized Cyber-203 computer program. Cases of both plane waves and spin modes are treated. Spin modes model the sound generated by a turbofan engine. Boundary conditions for both plane waves and spin modes are treated. Solutions obtained are compared with experiments conducted at NASA Langley Research Center.

  13. Anatomy of the nipple and breast ducts.

    PubMed

    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

  14. Levitated Duct Fan (LDF) Aircraft Auxiliary Generator

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Emerson, Dawn C.; Gallo, Christopher A.; Thompson, William K.

    2011-01-01

    This generator concept includes a novel stator and rotor architecture made from composite material with blades attached to the outer rotating shell of a ducted fan drum rotor, a non-contact support system between the stator and rotor using magnetic fields to provide levitation, and an integrated electromagnetic generation system. The magnetic suspension between the rotor and the stator suspends and supports the rotor within the stator housing using permanent magnets attached to the outer circumference of the drum rotor and passive levitation coils in the stator shell. The magnets are arranged in a Halbach array configuration.

  15. Live 3D image overlay for arterial duct closure with Amplatzer Duct Occluder II additional size.

    PubMed

    Goreczny, Sebstian; Morgan, Gareth J; Dryzek, Pawel

    2016-03-01

    Despite several reports describing echocardiography for the guidance of ductal closure, two-dimensional angiography remains the mainstay imaging tool; three-dimensional rotational angiography has the potential to overcome some of the drawbacks of standard angiography, and reconstructed image overlay provides reliable guidance for device placement. We describe arterial duct closure solely from venous approach guided by live three-dimensional image overlay.

  16. Effectiveness of duct sealing and duct insulation in multi-family buildings. Final report

    SciTech Connect

    Karins, N.H.; Tuluca, A.; Modera, M.

    1997-07-01

    This research investigated the cost-effectiveness of sealing and insulating the accessible portions of duct systems exposed to unconditioned areas in multifamily housing. Airflow and temperature measurements were performed in 25 apartments served by 10 systems a 9 multi-family properties. The measurements were performed before and after each retrofit, and included apartment airflow (supply and return), duct system temperatures, system fan flow and duct leakage area. The costs for each retrofit were recorded. The data were analyzed and used to develop a prototypical multifamily house. This prototype was used in energy simulations (DOE-2.1E) and air infiltration simulations (COMIS 2.1). The simulations were performed for two climates: New York City and Albany. In each climate, one simulation was performed assuming the basement was tight, and another assuming the basement was leaky. Simulation results and average retrofit costs were used to calculate cost-effectiveness. The results of the analysis indicate that sealing leaks of the accessible ductwork is cost-effective under all conditions simulated (simple payback was between 3 and 4 years). Insulating the accessible ductwork, however, is only cost-effective for buildings with leaky basement, in both climates (simple paybacks were less than 5 years). The simple payback period for insulating the ducts in buildings with tight basements was greater than 10 years, the threshold of cost-effectiveness for this research. 13 refs., 5 figs., 27 tabs.

  17. Is Duct to Duct biliary Anastomosis the Rule in Orthotopic Liver Transplantation?

    PubMed

    Selvakumar, N; Saha, Brig Anupam; Naidu, Surg Capt Sudeep

    2013-10-01

    Biliary complications after Liver Transplantation continue to be the major cause of morbidity in 11-25 % of patients. Biliary complications in patients who underwent orthotopic liver transplantation (OLT) at our institute between March 2007 and June 2010 were analyzed retrospectively. 32 patients underwent Deceased Donor Liver Transplantation (DDLT) and in 12 patients Living Donor Liver Transplantation (LDLT) was done. No patients were lost to follow up. Follow up ranged between 4 and 44 months. During the study period, 44 patients underwent orthotopic liver transplantation. Patients were divided into two groups: Biliary Complications group (BC) n = 5 and Non Biliary Complications group (NBC) n = 39. Biliary complications occurred in 15.9 % of patients. Bile leaks accounted for majority of biliary complications. Fifteen variables were analyzed as possible risk factors for biliary complications. Of these, split grafts, duct to duct biliary anastomosis and total blood loss were statistically significant (P < 0.05) for biliary complications. Endoscopic treatment was successful in managing biliary complications in 75 % of patients. Biliary complications are the most common major complications in orthotopic liver transplantation. Significant risk factors are split liver grafts and duct to duct biliary anastomosis. Increased blood loss is a predictor for post operative biliary complications. These complications should be managed by endoscopic interventions. Surgery is indicated following failure of endoscopic interventions. PMID:24426478

  18. Bile duct confluence: anatomic variations and its classification.

    PubMed

    Chaib, Eleazar; Kanas, Alexandre Fligelman; Galvão, Flavio Henrique Ferreira; D'Albuquerque, Luiz Augusto Carneiro

    2014-03-01

    Accurate knowledge of the anatomy of the bile ducts is critical for successfully hepato-biliary surgery. We describe the anatomical variations of the confluence of the bile ducts, their branches patterns, frequency and classification. From 1996 to 2011, we have collected data of the bile duct confluence. 2,032 and 1,014 anatomical variations of right and left bile ducts, respectively, were reviewed and classified according to the branching pattern. The frequencies of each type of the right hepatic duct (RHD) were as follows: Type A1-1,247 (61.3%); Type A2-296 (14.5%); Type A3-272 (13.3%); Type A4-124 (6.1%); Type A5-21 (1%) and others-72 (3.5%) and, for the left hepatic duct (LHD) was as follows: Type B1-773 (76.2%); Type B2-153 (15%); Type B3-38 (3.7%); Type B4-9 (0.8%); Type B5-29 (2.8%) and others-12 (1.1%). Atypical branching patterns of both the right and left hepatic ducts were found in 14 and 8%, respectively. The two most common variations of the RHD were right anterior and posterior hepatic ducts join together to form the RHD and trifurcation where the RHD is absent and right anterior and posterior hepatic ducts join directly to the confluence with the LHD to form the common hepatic duct. The two most common variations in the LHD were segment IV drainage to the left and right hepatic ducts.

  19. Ultrasound imaging of the mouse pancreatic duct using lipid microbubbles

    NASA Astrophysics Data System (ADS)

    Banerjee, B.; McKeown, K. R.; Skovan, B.; Ogram, E.; Ingram, P.; Ignatenko, N.; Paine-Murrieta, G.; Witte, R.; Matsunaga, T. O.

    2012-03-01

    Research requiring the murine pancreatic duct to be imaged is often challenging due to the difficulty in selectively cannulating the pancreatic duct. We have successfully catheterized the pancreatic duct through the common bile duct in severe combined immune deficient (SCID) mice and imaged the pancreatic duct with gas filled lipid microbubbles that increase ultrasound imaging sensitivity due to exquisite scattering at the gas/liquid interface. A SCID mouse was euthanized by CO2, a midline abdominal incision made, the common bile duct cut at its midpoint, a 2 cm, 32 gauge tip catheter was inserted about 1 mm into the duct and tied with suture. The duodenum and pancreas were excised, removed in toto, embedded in agar and an infusion pump was used to instill normal saline or lipid-coated microbubbles (10 million / ml) into the duct. B-mode images before and after infusion of the duct with microbubbles imaged the entire pancreatic duct (~ 1 cm) with high contrast. The microbubbles were cavitated by high mechanical index (HMI) ultrasound for imaging to be repeated. Our technique of catheterization and using lipid microbubbles as a contrast agent may provide an effective, affordable technique of imaging the murine pancreatic duct; cavitation with HMI ultrasound would enable repeated imaging to be performed and clustering of targeted microbubbles to receptors on ductal cells would allow pathology to be localized accurately. This research was supported by the Experimental Mouse Shared Service of the AZ Cancer Center (Grant Number P30CA023074, NIH/NCI and the GI SPORE (NIH/NCI P50 CA95060).

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Cholestasis‐induced adaptive remodeling of interlobular bile ducts

    PubMed Central

    Damle‐Vartak, Amruta; Richter, Beate; Dirsch, Olaf; Dahmen, Uta; Hammad, Seddik

    2016-01-01

    Cholestasis is a common complication in liver diseases that triggers a proliferative response of the biliary tree. Bile duct ligation (BDL) is a frequently used model of cholestasis in rodents. To determine which changes occur in the three‐dimensional (3D) architecture of the interlobular bile duct during cholestasis, we used 3D confocal imaging, surface reconstructions, and automated image quantification covering a period up to 28 days after BDL. We show a highly reproducible sequence of interlobular duct remodeling, where cholangiocyte proliferation initially causes corrugation of the luminal duct surface, leading to an approximately five‐fold increase in surface area. This is analogous to the function of villi in the intestine or sulci in the brain, where an expansion of area is achieved within a restricted volume. The increase in surface area is further enhanced by duct branching, branch elongation, and loop formation through self‐joining, whereby an initially relatively sparse mesh surrounding the portal vein becomes five‐fold denser through elongation, corrugation, and ramification. The number of connections between the bile duct and the lobular bile canalicular network by the canals of Hering decreases proportionally to the increase in bile duct length, suggesting that no novel connections are established. The diameter of the interlobular bile duct remains constant after BDL, a response that is qualitatively distinct from that of large bile ducts, which tend to enlarge their diameters. Therefore, volume enhancement is only due to net elongation of the ducts. Because curvature and tortuosity of the bile duct are unaltered, this enlargement of the biliary tree is caused by branching and not by convolution. Conclusion: BDL causes adaptive remodeling that aims at optimizing the intraluminal surface area by way of corrugation and branching. (Hepatology 2016;63:951–964) PMID:26610202

  2. Endoscopic lithotripsy for bile duct stones.

    PubMed

    Lee, J G; Leung, J W

    1993-01-01

    Endoscopic sphincterotomy and common duct stone extraction is successful in 85-90% of patients using conventional balloons and baskets. However, most patients with biliary stones > 2 cm will require mechanical, electrohydraulic, or laser lithotripsy prior to stone extraction. Mechanical lithotripsy is inexpensive, easy to perform, and effective in 80-90% of cases. Most failures result from inability to entrap the stone in the lithotripsy basket. These cases may be successfully treated using either electrohydraulic or laser lithotripsy (intraductal shockwave lithotripsy). In most cases, intraductal shockwave lithotripsy requires direct visual control. Due to difficulty with peroral cholangioscopy, these techniques will not be widely used until a smaller, more maneuverable "mother and baby scope" system is developed. We recommend mechanical lithotripsy as the initial treatment for large biliary stones. Failed cases should be referred to specialized centers for a repeat attempt with intraductal shockwave lithotripsy. With this approach, an experienced endoscopist is successful in removing biliary stones in over 95% of patients. Long term biliary stenting remains a viable option for the high risk patients with large common bile duct stones.

  3. Classification and management of bile duct injuries.

    PubMed

    Mercado, Miguel Angel; Domínguez, Ismael

    2011-04-27

    To review the classification and general guidelines for treatment of bile duct injury patients and their long term results. In a 20-year period, 510 complex circumferential injuries have been referred to our team for repair at the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" hospital in Mexico City and 198 elsewhere (private practice). The records at the third level Academic University Hospital were analyzed and divided into three periods of time: GI-1990-99 (33 cases), GII- 2000-2004 (139 cases) and GIII- 2004-2008 (140 cases). All patients were treated with a Roux en Y hepatojejunostomy. A decrease in using transanastomotic stents was observed (78% vs 2%, P = 0.0001). Partial segment IV and V resection was more frequently carried out (45% vs 75%, P = 0.2) (to obtain a high bilioenteric anastomosis). Operative mortality (3% vs 0.7%, P = 0.09), postoperative cholangitis (54% vs 13%, P = 0.0001), anastomosis strictures (30% vs 5%, P = 0.0001), short and long term complications and need for reoperation (surgical or radiological) (45% vs 11%, P = 0.0001) were significantly less in the last period. The authors concluded that transition to a high volume center has improved long term results for bile duct injury repair. Even interested and tertiary care centers have a learning curve.

  4. Collecting duct intercalated cell function and regulation.

    PubMed

    Roy, Ankita; Al-bataineh, Mohammad M; Pastor-Soler, Núria M

    2015-02-01

    Intercalated cells are kidney tubule epithelial cells with important roles in the regulation of acid-base homeostasis. However, in recent years the understanding of the function of the intercalated cell has become greatly enhanced and has shaped a new model for how the distal segments of the kidney tubule integrate salt and water reabsorption, potassium homeostasis, and acid-base status. These cells appear in the late distal convoluted tubule or in the connecting segment, depending on the species. They are most abundant in the collecting duct, where they can be detected all the way from the cortex to the initial part of the inner medulla. Intercalated cells are interspersed among the more numerous segment-specific principal cells. There are three types of intercalated cells, each having distinct structures and expressing different ensembles of transport proteins that translate into very different functions in the processing of the urine. This review includes recent findings on how intercalated cells regulate their intracellular milieu and contribute to acid-base regulation and sodium, chloride, and potassium homeostasis, thus highlighting their potential role as targets for the treatment of hypertension. Their novel regulation by paracrine signals in the collecting duct is also discussed. Finally, this article addresses their role as part of the innate immune system of the kidney tubule. PMID:25632105

  5. [Extracorporeal shockwave lithotripsy of problem bile duct calculi].

    PubMed

    Jakobeit, C; Greiner, L

    1993-02-01

    ESWL is a new gentle, very effective, poor-risk technique in treatment of extrahepatic problematic bile-duct stones. This method might substitute surgical choledochotomy to a great extent. ESWL is a new therapeutic alternative to achieve nonoperative freedom of stones or, at least, to treat biliary obstruction in intrahepatic bile-duct stones, which are not treatable by endoscopic operative methods.

  6. 11. VIEW OF A HEATING DUCT SITUATED SOUTHWEST OF THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. VIEW OF A HEATING DUCT SITUATED SOUTHWEST OF THE FAN HOUSE, ALONG THE MINE ROAD. THE BURNED RUINS OF THE MINE OFFICE ARE LOCATED ON THE FAR SIDE OF THE HEATING DUCT, TO THE NORTHWEST. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

  7. Long duct nacelle aerodynamic development for DC-10 derivatives

    NASA Technical Reports Server (NTRS)

    Patel, S. P.; Donelson, J. E.

    1980-01-01

    The results are presented of a wind tunnel test utilizing a 4.7-percent-scale semispan model of the DC-10 in the Calspan 8-foot transonic wind tunnel. The effect of a revised long-duct nacelle shape on the channel velocities, the incremental drag relative to the baseline long-duct nacelle, and channel velocities for the baseline long-duct nacelle were determined and compared with data obtained at Ames. The baseline and the revised long-duct nacelles are representative of a CF6-50 mixed-flow configuration and were evaluated on a model of a proposed DC-10 stretched-fuselage configuration. The results showed that the revised long-duct nacelle has an appreciable effect on the inboard channel velocities, resulting in an increased channel Mach number. However, the pressure recovery on the nacelle afterbody was about the same for both nacelles. The lift curves for both long-duct nacelle configurations were the same. The channel pressures measured at Calspan were in good agreement with those measured at Ames for the baseline long-duct nacelle. The incremental drag for the revised nacelle was measured as two to four counts (three counts is approximately equal to one percent of the airplane drag) higher than that of the baseline long-duct nacelle.

  8. Thermal performance of residential duct systems in basements

    NASA Astrophysics Data System (ADS)

    Treidler, Burke; Modera, Mark

    1994-01-01

    There are many unanswered questions about the typical effects of duct system operation on the infiltration rates and energy usage of single-family residences with HVAC systems in their basements. Results from preliminary field studies and computer simulations are used to examine the potential for improvements in efficiency of air distribution systems in such houses. The field studies comprise thermal and flow measurements on four houses in Maryland. The houses were found to have significant envelope leakage, duct leakage, and duct conduction losses. Simulations of a basement house, the characteristics of which were chosen from the measured houses, were performed to assess the energy savings potential for basement house. The simulations estimate that a nine percent reduction in space conditioning energy use is obtained by sealing eighty percent of the duct leaks and insulating ducks to an R-value of 0.88 (C x sq. m)/W(100 F x sq. ft x h/BTU) where they are exposed in the basement. To determine the maximum possible reduction in energy use, simulations were run with all ducts insulated to (17.6 C x sq m)/W(100 F x sq. ft x h/BTU) and with no duct leakage. A reduction of energy use by 14% is obtained by using perfect ducts instead of normal ducts.

  9. Wirsung and Santorini: the men behind the ducts.

    PubMed

    Flati, Giancarlo; Andrén-Sandberg, Ake

    2002-01-01

    During the 16th and 17th centuries, several important discoveries were accomplished by anatomists whose contribution has enlightened the most important anatomic structures of the pancreas. Following the earliest discoveries, researchers of several medical specialities further investigated the ductal pancreatic system. The accessory pancreatic duct with its minor papilla, the main pancreatic duct and the papilla major along with the confluence of the main pancreatic duct with the bile duct and pancreas divisum, have been the objects of interest of several personalities of the medical history. Eponyms in pancreatic anatomy were given to remember some of them, although anatomical misattributions are frequent and controversial. The aim of the authors was to dedicate a small tribute to the researchers who have written, during the last 500 years, important chapters of the medical history and who dedicated their lives to study the pancreatic ducts and their duodenal endings. Furthermore, a brief outlook was dedicated to the impact of anatomic variations and of embryologic anomalies of the pancreatic ducts in our clinical practice and in our actual understanding of duct-related diseases. The authors are confident that the genial curiosity of few extraordinary personalities of the past and the opportunities provided by modern technology continue to play a major role that may finally add wisdom to decision-making in dealing with duct-related biliopancreatic diseases and safety to diagnostic and therapeutic procedures employed.

  10. Sound waves in two-dimensional ducts with sinusoidal walls

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.

    1974-01-01

    The method of multiple scales is used to analyze the wave propagation in two-dimensional hard-walled ducts with sinusoidal walls. For traveling waves, resonance occurs whenever the wall wavenumber is equal to the difference of the wavenumbers of any two duct acoustic modes. The results show that neither of these resonating modes could occur without strongly generating the other.

  11. IET exhaust gas duct, system layout, plan, and section. shows ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    IET exhaust gas duct, system layout, plan, and section. shows mounting brackets, concrete braces, divided portion of duct, other details. Ralph M. Parsons 902-5-ANP-712-S 429. Date: May 1954. Approved by INEEL Classification Office for public release. INEEL index code no. 035-0712-60-693-106980 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  12. 91. VIEW OF OBSOLETE AIRCONDITIONING DUCTS LOCATED IN NORTHWEST CORNER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    91. VIEW OF OBSOLETE AIR-CONDITIONING DUCTS LOCATED IN NORTHWEST CORNER OF ROOM, ABOVE SLC-3E AUTOPILOT EQUIPMENT. DIGITAL COUNTDOWN AND HOLD CLOCKS ON WALL LEFT OF DUCTS - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  13. Duct thermal performance models for large commercial buildings

    SciTech Connect

    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, assess the impacts of

  14. Scale Model Experiments on Sound Propagation From a Mach 2.5 Cold Nitrogen Jet Flowing Through a Rigid-Walled Duct With a J-Deflector

    NASA Technical Reports Server (NTRS)

    Kandula, Max; Vu, Bruce

    2003-01-01

    The Launch Systems Testbed (LST) represents the evolution of vibroacoustics research and development work performed at NASA John F. Kennedy Space Center (KSC) over the last 15 years. The LST is located at the Launch Equipment Test Facility (LETF) in the KSC industrial complex. The LETF is operated by Sierra Lobo, Inc., as a member of University-Affiliated Technology Development Contract (USTDC) to KSC Spaceport and Engineering and Technology Directorate (YA), with ASRC Aerospace Corporation as a the prime contractor. Trajectory Simulation Mechanism (TSM) is a major component of the LST, developed specifically to simulate nonstationary acoustic loads on launch pad structures, vehicles, and payloads. TSM enhances the capabilities within LST for simulating launch environments of future vehicles. The scaled launch environments will be used to predict the full-scale launch environment via an appropriate scaling procedure. Air Force Research Laboratory (AFRL) has tasked NASA KSC to perform a basic technology test program in support of developing a low-cost clean pad (incorporating passive mitigation techniques) for future launch vehicles. The overall goal of the program is to develop innovative launch exhaust management systems, which effectively reduce launch acoustic environment with innovative duct designs, while eliminating traditional sound suppression water systems. Passive techniques, such as nontraditional duct geometries, resonators, and diffusers, etc., will be investigated. The overall goals are to advance innovative concepts for a clean pad while developing ideas to reduce transmitted sound via investigation and modeling of jet exhaust acoustic and flow field characteristics. The series of tests outlined in this report represent baseline tests and are geared towards defining the acoustic load environment on the TSM pad for open and closed duct configurations. This report summarizes the cold jet acoustic testing for Mach 2.5 supersonic nitrogen jet issuing

  15. An electronically tunable duct silencer using dielectric elastomer actuators.

    PubMed

    Lu, Zhenbo; Godaba, Hareesh; Cui, Yongdong; Foo, Choon Chiang; Debiasi, Marco; Zhu, Jian

    2015-09-01

    A duct silencer with tunable acoustic characteristics is presented in this paper. Dielectric elastomer, a smart material with lightweight, high elastic energy density and large deformation under high direct current/alternating current voltages, was used to fabricate this duct silencer. The acoustic performances and tunable mechanisms of this duct silencer were experimentally investigated. It was found that all the resonance peaks of this duct silencer could be adjusted using external control signals without any additional mechanical part. The physics of the tunable mechanism is further discussed based on the electro-mechanical interactions using finite element analysis. The present promising results also provide insight into the appropriateness of the duct silencer for possible use as next generation acoustic treatment device to replace the traditional acoustic treatment. PMID:26428819

  16. Regeneratively cooled transition duct with transversely buffered impingement nozzles

    SciTech Connect

    Morrison, Jay A; Lee, Ching-Pang; Crawford, Michael E

    2015-04-21

    A cooling arrangement (56) having: a duct (30) configured to receive hot gases (16) from a combustor; and a flow sleeve (50) surrounding the duct and defining a cooling plenum (52) there between, wherein the flow sleeve is configured to form impingement cooling jets (70) emanating from dimples (82) in the flow sleeve effective to predominately cool the duct in an impingement cooling zone (60), and wherein the flow sleeve defines a convection cooling zone (64) effective to cool the duct solely via a cross-flow (76), the cross-flow comprising cooling fluid (72) exhausting from the impingement cooling zone. In the impingement cooling zone an undimpled portion (84) of the flow sleeve tapers away from the duct as the undimpled portion nears the convection cooling zone. The flow sleeve is configured to effect a greater velocity of the cross-flow in the convection cooling zone than in the impingement cooling zone.

  17. An electronically tunable duct silencer using dielectric elastomer actuators.

    PubMed

    Lu, Zhenbo; Godaba, Hareesh; Cui, Yongdong; Foo, Choon Chiang; Debiasi, Marco; Zhu, Jian

    2015-09-01

    A duct silencer with tunable acoustic characteristics is presented in this paper. Dielectric elastomer, a smart material with lightweight, high elastic energy density and large deformation under high direct current/alternating current voltages, was used to fabricate this duct silencer. The acoustic performances and tunable mechanisms of this duct silencer were experimentally investigated. It was found that all the resonance peaks of this duct silencer could be adjusted using external control signals without any additional mechanical part. The physics of the tunable mechanism is further discussed based on the electro-mechanical interactions using finite element analysis. The present promising results also provide insight into the appropriateness of the duct silencer for possible use as next generation acoustic treatment device to replace the traditional acoustic treatment.

  18. Heat Transfer in Conical Corner and Short Superelliptical Transition Ducts

    NASA Technical Reports Server (NTRS)

    Poinsatte, Philip; Thurman, Douglas; Hippensteele, Steven

    2008-01-01

    Local surface heat transfer measurements were experimentally mapped using a transient liquid-crystal heat-transfer technique on the surface of two circular-to-rectangular transition ducts. One has a transition cross section defined by conical corners (Duct 1) and the other by an elliptical equation with changing coefficients (Duct 2). Duct 1 has a length-to-diameter ratio of 0.75 and an exit plane aspect ratio of 1.5. Duct 2 has a length-to-diameter ratio of 1.0 and an exit plane aspect ratio of 2.9. Test results are reported for various inlet-diameter-based Reynolds numbers ranging from 0.45 106 to 2.39 106 and two 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. Positive predictive value of cholescintigraphy in common bile duct obstruction

    SciTech Connect

    Lecklitner, M.L.; Austin, A.R.; Benedetto, A.R.; Growcock, G.W.

    1986-09-01

    Technetium-99m DISIDA imaging was employed in 400 patients to differentiate obstruction of the common bile duct from medical and other surgical causes of hyperbilirubinemia. Sequential anterior images demonstrated variable degrees of liver uptake, yet there was no evidence of intrabiliary or extrabiliary radioactivity for at least 4 hr after injection in 25 patients. Twenty-three patients were surgically documented to have complete obstruction of the common bile duct. One patient had hepatitis, and another had sickle cell crisis without bile duct obstruction. The remaining patients had either partial or no obstruction of the common bile duct. We conclude that the presence of liver uptake without evident biliary excretion by 4 hr on cholescintigraphy is highly sensitive and predictive of total obstruction of the common bile duct.

  20. Lacrimal Duct Occlusion Is Associated with Infectious Keratitis

    PubMed Central

    Li, Guigang; Guo, Jingmin; Liu, Rong; Hu, Weikun; Xu, Lingjuan; Wang, Juan; Cai, Subo; Zhang, Hong; Zhu, Yingting

    2016-01-01

    Background: To explore the prevalence of lacrimal duct obstruction in patients with infectious keratitis, and the necessity of lacrimal duct dredge in the treatment of human infectious keratitis. Methodology/Principle Findings: The design is prospective, non-control case series. Thirty-one eyes from twenty-eight continuous patients with infectious keratitis were included in this study. The presence/absence of lacrimal duct obstruction was determined by the lacrimal duct irrigation test. The diagnosis of infectious keratitis was made based on clinical manifestations, cornea scraping microscopic examination and bacterial/fungus culture. Diagnosis of viral keratitis was set up based on the recurrent history, deep neovascularization and typical outlook of the cornea scar. The treatment of keratitis included drugs, eye drops or surgery, while treatment of chronic dacryocystitis was lacrimal duct dredging with supporting tube implantation surgery. In the thirty-one eyes with infectious keratitis, fifteen suffered from fungal keratitis (48%), two bacterial keratitis (6%), and fourteen viral keratitis (45%). Eleven eyes (35%) from ten patients with infectious keratitis also suffered from lacrimal duct obstruction. In those cases, six eyes also suffered from lower canalicular obstruction, three nasolacrimal duct obstruction and chronic dacryocystitis, one a combination of upper and lower canalicular obstruction, one upper canalicular obstruction. After local and systemic applications of anti-bacterial, anti-viral, anti-fungal and anti-inflammatory drugs, twenty-eight eyes (90%) recovered within three weeks, while the ulceration of three patients required the lacrimal duct dredging and supporting tube implantation surgery for the healing. Conclusions: Herein, we first report that the prevalence of infectious keratitis is closely correlated to the occurrence of lacrimal duct obstruction. When both confirmed, simultaneous treatment of keratitis and lacrimal duct obstruction

  1. Duct injection technology prototype development: Nozzle development Subtask 4.1, Atomizer specifications for duct injection technology. Topical report 8

    SciTech Connect

    Not Available

    1992-02-01

    Babcock & Wilcox has conducted a program to identify atomizers appropriate for successful in-duct injection of humidification water and lime slurries. The purpose of this program was to identify and quantify atomizer spray and performance criteria that affect the operations and reliability of the in-duct SO{sub 2} removal process, and compare commercially available atomizers to these criteria.

  2. Far-field noise and internal modes from a ducted propeller at simulated aircraft takeoff conditions

    NASA Astrophysics Data System (ADS)

    Woodward, Richard P.; Bock, Lawrence A.; Heidelberg, Laurence J.; Hall, David G.

    The ducted propeller offers structural and acoustic benefits typical of conventional turbofan engines while retaining much of the aeroacoustic benefits of the unducted propeller. A model Advanced Ducted Propeller (ADP) was tested in the NASA Lewis Low-Speed Anechoic Wind Tunnel at a simulated takeoff velocity of Mach 0.2. The ADP model was designed and manufactured by the Pratt and Whitney Division of United Technologies. The 16-blade rotor ADP was tested with 22- and 40-vane stators to achieve cut-on and cut-off criterion with respect to propagation of the fundamental rotor-stator interaction tone. Additional test parameters included three inlet lengths, three nozzle sizes, two spinner configurations, and two rotor rub strip configurations. The model was tested over a range of rotor blade setting angles and propeller axis angles-of-attack. Acoustic data were taken with a sideline translating microphone probe and with a unique inlet microphone probe which identified inlet rotating acoustic modes. The beneficial acoustic effects of cut-off were clearly demonstrated. A 5 dB fundamental tone reduction was associated with the long inlet and 40-vane sector, which may relate to inlet duct geometry. The fundamental tone level was essentially unaffected by propeller axis angle-of-attack at rotor speeds of at least 96 percent design.

  3. Far-field noise and internal modes from a ducted propeller at simulated aircraft takeoff conditions

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Bock, Lawrence A.; Heidelberg, Laurence J.; Hall, David G.

    1992-01-01

    The ducted propeller offers structural and acoustic benefits typical of conventional turbofan engines while retaining much of the aeroacoustic benefits of the unducted propeller. A model Advanced Ducted Propeller (ADP) was tested in the NASA Lewis Low-Speed Anechoic Wind Tunnel at a simulated takeoff velocity of Mach 0.2. The ADP model was designed and manufactured by the Pratt and Whitney Division of United Technologies. The 16-blade rotor ADP was tested with 22- and 40-vane stators to achieve cut-on and cut-off criterion with respect to propagation of the fundamental rotor-stator interaction tone. Additional test parameters included three inlet lengths, three nozzle sizes, two spinner configurations, and two rotor rub strip configurations. The model was tested over a range of rotor blade setting angles and propeller axis angles-of-attack. Acoustic data were taken with a sideline translating microphone probe and with a unique inlet microphone probe which identified inlet rotating acoustic modes. The beneficial acoustic effects of cut-off were clearly demonstrated. A 5 dB fundamental tone reduction was associated with the long inlet and 40-vane sector, which may relate to inlet duct geometry. The fundamental tone level was essentially unaffected by propeller axis angle-of-attack at rotor speeds of at least 96 percent design.

  4. Salivary duct carcinoma in the mandible.

    PubMed

    Shi, Shuang; Fang, Qi-Gen; Sun, Changfu

    2014-11-01

    We reported 1 case of salivary duct carcinoma (SDC) in the mandible. The patient complained of pain and a growing mass in the right submandibular area for approximately 2 months. On clinical examination, there was a mass under the right angle of the mandible with a size of approximately 3 × 3 cm, a smooth surface, a poor activity, and a hard texture. Panoramic radiograph revealed poorly circumscribed area. Computed tomography presented mandible central destruction. Biopsy examination showed a malignant tumor that originated in the central epithelium of the mandible. An operation of unilateral selective neck dissection and mandible subtotal ectomy was performed. Postoperative pathology reported SDC. The patient received postoperative radiation and stayed alive at last follow-up without disease recurrence. Ablative resection and postoperative radiotherapy were the standard treatment stratagem for SDC, but trastuzumab therapy might play a key role in treating the disease in future.

  5. Acoustic propagation in rigid ducts with blockage

    NASA Technical Reports Server (NTRS)

    El-Raheb, M.; Wagner, P.

    1982-01-01

    Acoustic levitation has been suggested for moving nonmagnetic material in furnaces for heat processing in space experiments. Basically, acoustic standing waves under resonant conditions are excited in the cavity of the furnace while the material blockage is located at a pressure node and thus at a maximum gradient. The position of the blockage is controlled by displacing the node as a result of frequency change. The present investigation is concerned with the effect of blockage on the longitudinal and transverse resonances of a cylindrical cavity, taking into account the results of a one-dimensional and three-dimensional (3-D) analysis. Based on a Green's function surface element method, 3-D analysis is tested experimentally and proved to be accurate over a wide range of geometric parameters and boundary shapes. The shift in resonance depends on the change in pressure gradient and duct shortening caused by the blockage.

  6. Acoustic propagation in rigid ducts with blockage

    NASA Astrophysics Data System (ADS)

    El-Raheb, M.; Wagner, P.

    1982-09-01

    Acoustic levitation has been suggested for moving nonmagnetic material in furnaces for heat processing in space experiments. Basically, acoustic standing waves under resonant conditions are excited in the cavity of the furnace while the material blockage is located at a pressure node and thus at a maximum gradient. The position of the blockage is controlled by displacing the node as a result of frequency change. The present investigation is concerned with the effect of blockage on the longitudinal and transverse resonances of a cylindrical cavity, taking into account the results of a one-dimensional and three-dimensional (3-D) analysis. Based on a Green's function surface element method, 3-D analysis is tested experimentally and proved to be accurate over a wide range of geometric parameters and boundary shapes. The shift in resonance depends on the change in pressure gradient and duct shortening caused by the blockage.

  7. Primary Bile Duct Melanoma Causing Obstructive Jaundice

    PubMed Central

    Addepally, Naga S.; Klair, Jagpal S.; Lai, Keith; Aduli, Farshad

    2016-01-01

    Malignant melanoma is one of the few malignancies that are well known for unusual behavior. Primary malignant melanoma usually originates from squamous epithelium of skin, mucous membranes, retina, and uvea. Although melanoma can metastasize to any part of the body, including biliary tract, primary malignant melanoma of bile ducts is an extremely rare entity. We present a 52-year-old man who presented with 5-month epigastric pain and 15-pound weight loss, with 1-week duration of jaundice, nausea/vomiting, pale stools, and dark urine, blood work suggested cholestatic jaundice. Imaging revealed a large perihilar/peripancreatic mass involving the portal vein and hepatic artery, and intrahepatic biliary dilation. Biliary brushings revealed neoplastic cells strongly suggestive of malignant melanoma. PMID:27807580

  8. Salivary duct carcinoma in the mandible.

    PubMed

    Shi, Shuang; Fang, Qi-Gen; Sun, Changfu

    2014-11-01

    We reported 1 case of salivary duct carcinoma (SDC) in the mandible. The patient complained of pain and a growing mass in the right submandibular area for approximately 2 months. On clinical examination, there was a mass under the right angle of the mandible with a size of approximately 3 × 3 cm, a smooth surface, a poor activity, and a hard texture. Panoramic radiograph revealed poorly circumscribed area. Computed tomography presented mandible central destruction. Biopsy examination showed a malignant tumor that originated in the central epithelium of the mandible. An operation of unilateral selective neck dissection and mandible subtotal ectomy was performed. Postoperative pathology reported SDC. The patient received postoperative radiation and stayed alive at last follow-up without disease recurrence. Ablative resection and postoperative radiotherapy were the standard treatment stratagem for SDC, but trastuzumab therapy might play a key role in treating the disease in future. PMID:25377985

  9. Spontaneous perforation of the right hepatic duct.

    PubMed

    Nguyen, W D; Daza, E

    2001-01-01

    Spontaneous perforation of the biliary ductal system is a rare cause of peritonitis with a high morbidity and mortality rate. We present a case of an 80-year-old female who presented to the Emergency Department with acute onset abdominal pain and peritoneal signs. She was taken to the operating room for exploratory laparotomy and discovered to have a perforation of her right hepatic duct. Several risk factors were found to play a role in her biliary perforation: biliary calculi, infection, and vessel thrombosis. She underwent a cholecystectomy, choledochotomy with removal of gallstones, repair of the perforation, and placement of a T-tube. She had a prolonged recovery in the intensive care unit and was eventually discharged to a skilled nursing facility. We conclude that the management of this unique and highly fatal disease can be applied with an excellent outcome.

  10. Shockwave lithotripsy of salivary duct stones.

    PubMed

    Iro, H; Schneider, H T; Födra, C; Waitz, G; Nitsche, N; Heinritz, H H; Benninger, J; Ell, C

    1992-05-30

    Surgical extirpation of the affected gland has been necessary for cases of sialolithiasis in which the stone cannot be removed by dilatation or dissection of the salivary duct. The ability of the piezoelectric lithotripter to deliver shockwaves to a small focus makes extracorporeal shockwave lithotripsy of salivary gland stones potentially safe. Its safety and efficacy have been assessed in 51 patients with symptomatic solitary salivary stones that could not be removed by conservative measures. The stones had a median diameter of 8 (range 4-18) mm and were located in the submandibular gland in 69% of patients and in the parotid gland in 31%. A total of 72 shockwave treatment sessions (maximum 3 per patient) were given under continuous sonographic monitoring. In 45 patients (88%) complete fragmentation (fragments less than or equal to 3 mm) of the concrements was achieved. No patient needed anaesthesia, sedatives, or analgesics. The only untoward effects were localised petechial haemorrhages after 10 (13%) out of 72 treatments and transient swelling of the gland immediately after delivery of shockwave in 2/72 (3%) sessions. 20 weeks after the first session 90% (46/51) of patients were free of discomfort, and 53% (27/51) were stone free. Stone-clearance rate was higher among patients with stones in the parotid gland (81%) than among those with stones of the submandibular gland (40%). Auxiliary measures such as dilatation or dissection of the salivary duct were required only in patients with stones in the submandibular gland (20%). No long-term damage to the treated salivary gland or to adjacent tissue structures was noted during the median follow-up of 9 (1-24) months. Extracorporeal piezoelectric shockwave therapy seems likely to be safe, comfortable, and effective minimally-invasive, non-surgical treatment for salivary stones.

  11. Modes in Lined Wedge-Shaped Ducts

    NASA Astrophysics Data System (ADS)

    Mechel, F. P.

    1998-10-01

    The computation of sound fields in wedge-shaped spaces with an absorbing boundary (the seabed) is a classical problem of underwater acoustics, covered by a large number of publications. All known solutions are approximations which are restricted to very small wedge angles θ0, typically less than 3°. In underwater acoustics it is further assumed thatk0r≫1. The background of the present paper is the performance of lined conical duct sections in silencers. There the wedge angle can attain values around 45°, and the assumptionk0r≫1 cannot be made. The absorber of the lined boundary here is supposed to be locally reacting (for reasons of simplicity); it can be characterized by a normalized surface admittanceG0. The problems of the analysis arise from the fact, that the fundamental field solutions (modes) can no longer be separated in the cylindrical co-ordinatesr, θ if a boundary is absorbing. This paper describes analytical solutions for the construction of modes in lined wedge-shaped ducts; they can be applied for wedge angles up to about 15° (a subsequent paper will describe a method for angles up to about 45° but only moderatek0rvalues). In the solutions, use is made of “fictitious modes”, which satisfy the boundary conditions and solve a part of the wave equation. They must be completed by a “modal rest” to satisfy approximately the full wave equation. In the first solution, the rest is synthesized by fictitious modes; in the second solution, a separate function is introduced for the rest. Modes for typical underwater acoustics conditions will arise as side products.

  12. Coupling Between Mesospheric and Lower-Thermospheric Ducted Gravity Waves

    NASA Astrophysics Data System (ADS)

    Snively, J. B.; Walterscheid, R. L.; Hickey, M. P.

    2011-12-01

    The structure of the mesosphere and lower thermosphere (MLT) region is at times able to support ducted gravity wave propagation in a dual duct system: a lower-thermospheric thermal duct (LTD) that is always present, and an upper-mesospheric thermal duct that forms from an upper-mesospheric inversion layer (MIL). The combined effects of temperature and wind structure (sometimes to the extent of causing "Doppler" ducting, where wind is the Doppler shift becomes the dominant trapping mechanism) may lead to strongly-resonant ducted wave modes that can be easily forced to large amplitude. These modes may be initially excited by mechanisms such as gravity wave breaking or nonlinear interaction at duct altitudes [e.g., Snively and Pasko, JGR, 113, A06303, 2008], or via upward propagating linear waves which tunnel through the lower duct boundaries. In the latter case, excitation to large amplitudes is favored if the wave frequency and wavenumber closely match a duct resonance mode. Even waves that are not fully resonant may tunnel effectively between ducts, leading to dissipation as the waves ascend vertically [e.g., Snively and Taylor, AGU FM, SA54A-04, 2008]. Here we investigate cases where resonant duct modes are shared between the LTD and MIL [e.g., Walterscheid and Hickey, JGR, 114, D19109, 2009], allowing strong waves in the MIL to effectively excite even stronger waves in the LTD. Using steady-state linear and nonlinear time-dependent models in combination, we examine the coupling between MIL and LTD modes, and the generation and evolution of the large amplitude ducted wave modes. The linear model is first used to identify resonance modes, and the nonlinear model is then used to investigate the evolution of waves, from moderate-amplitude quasi-linear waves to large-amplitude nonlinear waves approaching the onset of breaking. We find that waves forced in one duct can profoundly affect the other, especially under resonant conditions where large amplitudes may be

  13. Developing flow in S-shaped ducts. 1: Square cross-section duct

    NASA Technical Reports Server (NTRS)

    Taylor, A. M. K. P.; Whitelaw, J. H.; Yianneskis, M.

    1982-01-01

    Laser-Doppler velocimetry was used to measure the laminar and turbulent flow in an S-duct formed with two 22.5 deg sectors of a bend with ratio of mean radius of curvature to hydraulic diameter of 7.0. The boundary layers at the inlet to the bend were about 25% and 15% of the hydraulic diameter for the laminar and turbulent flows, respectively. Pressure-driven secondary flows develop in the first half of the S-duct and persist into the second half but are largely reversed by the exit plane as a consequence of the change in the sense of curvature. There is, however, a region near the outer wall of the second bend where the redistribution of the streamwise isotachs results in a reinforcement of the secondary flow which was established in the first half of the S-duct. The net redistribution of the streamwise isotachs is comparable to that occurring in unidirectional bends of stronger curvature. The wall pressure distribution was also measured for the turbulent flow and quantifies the expected large variations in the longitudinal pressure gradient distributions which occur at different radial locations.

  14. Intraductal papillary neoplasm of the bile ducts: A case report and literature review

    PubMed Central

    Tan, Yaohong; Milikowski, Clara; Toribio, Yanelba; Singer, Adam; Rojas, Claudia P; Garcia-Buitrago, Monica T

    2015-01-01

    Intraductal papillary neoplasm of the bile duct (IPNB) is a rare bile duct neoplasm mostly found in far eastern nations where hepatolithiasis and clonorchiasis infections are endemic. In western countries, it is very rare and the etiology is unknown. In this article, we report the first IPNB patient we encountered in our clinic and a literature review. The patient is a 38-year-old female with a history of choledocholithiasis who presented with obstructive jaundice. She was found to have a papillary mass at the junction of the right hepatic duct and common hepatic duct with six masses in the liver parenchyma. The immunophenotypic and histologic features of the tumor are consistent with IPNB, gastric subtype. The patient had a partial hepatectomy and has been receiving palliative chemotherapy. In a search of PubMed database, we collected 354 IPNB patients reported in 22 articles. In these patients, 52.8% were from Japan and 27.7% were from western countries including the United States (11.0%). The age of the patients ranged from 35 to 80 years old with an average of 64.6. Male/female ratio was 1.5. Macroscopically, 57.5% of the tumors were in the left lobe and 29.5% were in the right lobe. The average size of the tumor were 4.2 cm at the time of diagnosis. Histologically, pancreato-biliary subtype accounted for 41.8%, intestinal 28.0%, gastric 13.5% and oncocytic 16%. An invasive component is most often present in the pancreato-biliary and gastric subtypes. Despite recent advanced technologies, diagnosis of IPNB is still challenging, especially in western countries due to its rarity. Defined clinico-pathologic features are in demand for the accurate diagnosis and proper treatment. PMID:26604656

  15. A quantitative analysis of electrolyte exchange in the salivary duct

    PubMed Central

    Catalán, Marcelo A.; Melvin, James E.; Yule, David I.; Crampin, Edmund J.; Sneyd, James

    2012-01-01

    A healthy salivary gland secretes saliva in two stages. First, acinar cells generate primary saliva, a plasma-like, isotonic fluid high in Na+ and Cl−. In the second stage, the ducts exchange Na+ and Cl− for K+ and HCO3−, producing a hypotonic final saliva with no apparent loss in volume. We have developed a tool that aims to understand how the ducts achieve this electrolyte exchange while maintaining the same volume. This tool is part of a larger multiscale model of the salivary gland and can be used at the duct or gland level to investigate the effects of genetic and chemical alterations. In this study, we construct a radially symmetric mathematical model of the mouse salivary gland duct, representing the lumen, the cell, and the interstitium. For a given flow and primary saliva composition, we predict the potential differences and the luminal and cytosolic concentrations along a duct. Our model accounts well for experimental data obtained in wild-type animals as well as knockouts and chemical inhibitors. Additionally, the luminal membrane potential of the duct cells is predicted to be very depolarized compared with acinar cells. We investigate the effects of an electrogenic vs. electroneutral anion exchanger in the luminal membrane on concentration and the potential difference across the luminal membrane as well as how impairing the cystic fibrosis transmembrane conductance regulator channel affects other ion transporting mechanisms. Our model suggests the electrogenicity of the anion exchanger has little effect in the submandibular duct. PMID:22899825

  16. Thermal considerations on the design and operation of lens ducts

    NASA Astrophysics Data System (ADS)

    Golnabi, H.

    2003-09-01

    In this paper, heat effects due to powerful pump beam in the lens duct delivery system is investigated and subsequent thermal effects are described. Temperature raise in the device, thermal loading, and material considerations for the lens ducts fabrication are reported. For an absorbed intensity of 10 W/cm2 in a 4 cm-long lens duct, the temperature difference between the midpoint and its faces, for a lens duct made from borosilicate is 7.05°C, for sapphire 4.01°C, and for synthetic fused silica is the smallest value of 0.54°C. For a typical absorbed intensity of 1.4 W/cm2 in a 4 cm-long lens duct, with a steady-state time constant of 120 s, the fractional thermal loading is 1.98% for BK-7, 1.89% for sapphire, and only 0.16% for synthetic fused silica. By considering different glass materials, the overall results show that synthetic fused silica is superior to some other materials for the fabrication of a lens duct. The reported analytical method and the results of parametric studies can be helpful in material selection and construction of an effective lens duct.

  17. Magnetic Resonance Sialography Findings of Submandibular Ducts Imaging

    PubMed Central

    Karaca Erdoğan, Nezahat; Altay, Canan; Özenler, Nesibe; Bozkurt, Tuğba; Uluç, Engin; Dirim Mete, Berna; Özdemir, İsmail

    2013-01-01

    Purpose. We aimed to assess the problem solving capability of magnetic resonance sialography (MR sialography), a noninvasive method for imaging submandibular gland ducts and determining duct-related pathologies, by comparing diseased and healthy cases. Materials and Methods. We conducted radiological assessment on a total of 60 submandibular glands (mean age 44.7) in 20 cases and 10 volunteers. MR sialography examinations were conducted with single-shot fast spin-echo sequence by using a surface coil placed on the submandibular gland. Each gland was evaluated in terms of the length, width and stricture of the main duct, as well as the difference between the intraparenchymal duct width, and the main duct width. Statistical analysis was performed. Results. In the MR sialography the primary duct mean length was determined as 51 mm (40–57 mm) in all submandibular glands. On the MR sialography imaging, the visualization ratio of the ductal system of submandibular gland was evaluated in the cases and volunteers. Conclusion. MR sialography is an effective and a noninvasive method in imaging submandibular gland ducts, demonstrating the presence, location and degree of stricture/dilatation, and elucidating the disease etiology. PMID:23984362

  18. In-Duct and Far-Field Experimental Measrements from the ANCF for the Purpose of Improved Broadband Liner Optimization

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.; Jones, Michael G.; Nark, Douglas M.

    2014-01-01

    A process for the design and evaluation of novel broadband acoustic liner concepts with limited fan source information is being evaluated. A pair of advanced broad-bandwidth liners were designed and manufactured for the NASA Glenn Research Center's Advanced Noise Control Fan (ANCF): (i) a constant impedance liner and (ii) a variable impedance liner. The insertion loss of both liners was measured in-duct utilizing the ANCF's Configurable Fan Artificial Noise System in a clean configuration with no-flow. Additionally, the acoustic characteristics of the Variable Impedance Liner were measured in the standard ANCF configuration with and without flow. The experimental setup, in-duct mode power levels, and far-field directivity are presented herein.

  19. Filling defects in the pancreatic duct on endoscopic retrograde pancreatography.

    PubMed

    Taylor, A J; Carmody, T J; Schmalz, M J; Wiedmeyer, D A; Stewart, E T

    1992-12-01

    Filling defects in the pancreatic duct are a frequent finding during endoscopic retrograde pancreatography (ERP) and have a variety of causes. Some filling defects may be artifactual or related to technical factors and, once their origin is recognized, can be disregarded. Others may be due to acute changes of pancreatitis and should prompt more careful injection of contrast material into the duct. Intraluminal masses may represent calculi or a neoplasm, either of which may require surgery or endoscopic intervention. The exact nature of these filling defects may not be apparent on radiographs, and other studies may be needed. This article reviews our approach to the evaluation of filling defects in the pancreatic duct.

  20. Subsonic Flows through S-Ducts with Flow Control

    NASA Astrophysics Data System (ADS)

    Chen, Yi

    An inlet duct of an aircraft connects the air intake mounted on the fuselage to the engine within the aircraft body. The ideal outflow quality of the duct is steady, uniform and of high total pressure. Recently compact S-shaped inlet ducts are drawing more attention in the design of UAVs with short propulsion system. Compact ducts usually involve strong streamwise adverse pressure gradient and transverse secondary flow, leading to large-scale harmful vortical structures in the outflow. To improve the outflow quality modern flow control techniques have to be applied. Before designing successful flow control methods a solid understanding of the baseline flow field with the duct is crucial. In this work the fundamental mechanism of how the three dimensional flow topology evolves when the relevant parameters such as the duct geometry and boundary layer thickness are varied, is studied carefully. Two distinct secondary-flow patterns are identified. For the first time the sensitivity of the flow topology to the inflow boundary layer thickness in long ducts is clearly addressed. The interaction between the transverse motion induced by the transverse pressure gradient and the streamwise separation is revealed as the crucial reason for the various flow patterns existing in short ducts. A non-symmetric flow pattern is identified for the first time in both experiments and simulations in short ducts in which the intensity of the streamwise separation and the transverse invasion are in the same order of magnitude. A theory of energy accumulation and solution bifurcation is used to give a reasonable explanation for this non-symmetry. After gaining the knowledge of where and how the harmful vortical structures are generated several flow control techniques are tested to achieve a better outflow quality. The analysis of the flow control cases also provides a deeper insight into the behavior of the three-dimensional flow within the ducts. The conventional separation control method

  1. SSME 3-D Turnaround Duct flow analysis - CFD predictions

    NASA Technical Reports Server (NTRS)

    Brankovic, Andreja; Stowers, Steven T.; Mcconnaughey, Paul

    1988-01-01

    CFD analysis is presently employed to obtain an improved flowfield for an individual flowpath in the case of the Space Shuttle Main Engine's High Pressure Fuel Turbopump Turn-Around Duct (TAD), which conducts the flow exiting from the gas turbines into the fuel bowl. It is demonstrated that the application of CFD to TAD flow analysis, giving attention to the duct's configuration and to the number, shape, and alignment of the diffuser struts, can enhance understanding of flow physics and result in improved duct design and performance.

  2. Finite-amplitude waves in cylindrical lined ducts

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.; Tsai, M.-S.

    1974-01-01

    A second-order uniformly valid expansion is obtained for nonlinear waves propagating in a cylindrical duct lined with a point-reacting acoustic material that consists of a porous sheet followed by honey-comb cavities and backed by the impervious walls of the duct. The effect of the liner is taken into account by coupling the waves in the duct with those in the liner. As in the two-dimensional case, the nonlinearity increases the attenuation rate at all frequencies except in narrow bandwidths around the resonant frequencies, irrespective of the geometrical dimensions of the liner or the acoustic properties of the porous sheet.

  3. Flow in Idealised Compliant Human Cystic Duct Models

    NASA Astrophysics Data System (ADS)

    Al-Atabi, M.; Chin, S. B.; Beck, S.; Luo, X. Y.

    The functions of the cystic duct and the role of its complicated geometry (in particular the valves of Heister), in the delivery of bile flow have always been a subject of speculation. This paper reports on an experimental investigation of the flow in idealised, compliant cystic duct models. The valves of Heister were idealised using eight semi-circular alternating baffles fitted inside the compliant tubes. These tubes were arranged in configurations representing the anatomical configurations of real cystic ducts. Models both with and without baffles were tested for comparison. The results show that the valves of Heister seem to play a role in facilitating both the filling and emptying of the gallbladder.

  4. Transition duct with late injection in turbine system

    SciTech Connect

    LeBegue, Jeffrey Scott; Pentecost, Ronnie Ray; Flanagan, James Scott; Kim, Won -Wook; McMahan, Kevin Weston

    2015-09-15

    A system for supplying an injection fluid to a combustor is disclosed. The system includes a transition duct comprising 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 passage defines a combustion chamber. The system further includes a tube providing fluid communication for the injection fluid to flow through the transition duct and into the combustion chamber.

  5. Hybrid method of transurethral resection of ejaculatory ducts using holmium:yttriumaluminium garnet laser on complete ejaculatory duct obstruction.

    PubMed

    Lee, Joo Yong; Diaz, Richilda Red; Choi, Young Deuk; Cho, Kang Su

    2013-07-01

    A 32-year old single man presented with azoospermia and low semen volume which was noted one and half a year ago. Transrectal ultrasonography and seminal vesiculography were performed to evaluate ejaculatory duct obstruction, and transurethral resection of the ejaculatory duct was performed using a hybrid technique of holmium:yttriumaluminium garnet laser with monopolar transurethral resection to overcome the narrow prostatic urethra. To our knowledge, this is the first report on the successful outcome of a hybrid technique applied for transurethral resection of the ejaculatory duct.

  6. Nasolacrimal Duct Mucocele: Case Report and Literature Review

    PubMed Central

    Britto, Fernanda Carneiro Corujeira de; Rosier, Vitor Veloso; Luz, Tovar Vicente; Verde, Raquel Crisóstomo Lima; Lima, Clara Mônica Figueiredo de; Lessa, Marcus Miranda

    2014-01-01

    Introduction Mucoceles are benign expansive cystic formations, composed of a mucus-secreting epithelium (respiratory or pseudostratified epithelium). Nasolacrimal mucocele occurs in a small proportion of children with nasolacrimal duct obstruction and is characterized by a cystic mass in the medial canthus with dilation of the nasolacrimal duct; although dacryocystoceles are rare in adults, they have been reported in patients with trachoma. Objective Discuss clinical aspects, diagnosis, and therapeutic management of mucocele of nasolacrimal duct based on literature review. Resumed Report The authors report a case of bilateral congenital nasolacrimal duct cysts in a 30-year-old man, identified as a tumor in the topography of both lacrimal sacs since birth without associated symptoms. The patient underwent successive surgical treatments, leading to recurrence of the tumor at the right side and recurrent local infections. Conclusion Endoscopic dacryocystorhinostomy has been increasingly used with good results and success rates similar to the external access. PMID:25992160

  7. Diaphragm eliminates leakage in cryogenic fluid duct coupling

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Duct coupling with nickel steel diaphragm of low thermal expansivity is leakproof when used with cryogenic fluids. The diaphragm, located between the two flanges of the coupling, reduces axial shrinkage at the coupling flanges to a minimum.

  8. Ducting arrangement for cooling a gas turbine structure

    SciTech Connect

    Lee, Ching-Pang; Morrison, Jay A.

    2015-07-21

    A ducting arrangement (10) for a can annular gas turbine engine, including: a duct (12, 14) disposed between a combustor (16) and a first row of turbine blades and defining a hot gas path (30) therein, the duct (12, 14) having raised geometric features (54) incorporated into an outer surface (80); and a flow sleeve (72) defining a cooling flow path (84) between an inner surface (78) of the flow sleeve (72) and the duct outer surface (80). After a cooling fluid (86) traverses a relatively upstream raised geometric feature (90), the inner surface (78) of the flow sleeve (72) is effective to direct the cooling fluid (86) toward a landing (94) separating the relatively upstream raised geometric feature (90) from a relatively downstream raised geometric feature (94).

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

    MedlinePlus

    ... the large intestine called ulcerative colitis. Bile duct stones , which are similar to, but much smaller than ... between ulcerative colitis and primary sclerosing cholangitis. Older age Older people are more likely than younger people ...

  10. 76. DETAIL OF AIRCONDITIONING DUCT BETWEEN PORTABLE PAYLOAD AIRCONDITIONING SYSTEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    76. DETAIL OF AIR-CONDITIONING DUCT BETWEEN PORTABLE PAYLOAD AIR-CONDITIONING SYSTEM AND LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  11. 54. DETAIL OF AIRCONDITIONING EXHAUST DUCTS ON NORTH FACE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    54. DETAIL OF AIR-CONDITIONING EXHAUST DUCTS ON NORTH FACE OF ERECT UMBILICAL MAST - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  12. Bulk reaction modeling of ducts with and without mean flow

    NASA Astrophysics Data System (ADS)

    Kakoty, S. K.; Roy, V. K.

    2002-07-01

    A general formulation for analysis of sound field in a uniform flow duct lined with bulk-reacting sound-absorbing material is presented here. Presented theoretical model predicts the rate of attenuation for symmetric as well as asymmetric modes in rectangular duct lined with loosely bound (bulk-reacting) sound-absorbing material, which allows acoustic propagation through the lining. The nature of attenuation in rectangular ducts lined on two and four sides with and without mean flow is discussed. Computed results are compared with published theoretical and experimental results. The presented model can be used as guidelines for the acoustic design of silencers, air-conditioning ducts, industrial fans, and other similar applications. copyright 2002 Acoustical Society of America.

  13. 68. Credit FM. Detail showing operators. Note cooling duct (now ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    68. Credit FM. Detail showing operators. Note cooling duct (now removed), governor (now removed), hand-operated needle valve controls (now removed). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  14. Materials for outlet ducts in wet FGD systems

    SciTech Connect

    Rosenberg, H.S.; Koch, G.H.; Kistler, C.W.; Beavers, J.A.; Meadows, M.L.; Stewart, D.A.; Dene, C.E.

    1985-01-01

    It was found that the major materials problems are occurring with outlet ducts and stack linings. Outlet ducts and stacks are critical components in that failures may require complete boiler shutdown and loss of generating capacity for lengthy periods due to the lack of standby components or bypass capability. Accordingly, EPRI funded a study by Battelle on the performance of candidate materials in the outlet ducts of FGD systems at two utility plants. Because of the impact of materials failures on FGD system reliability, EPRI is currently funding a study by Battelle on the causes of these failures. This study involves site visits for field evaluations of the failures, laboratory analyses of samples collected in the field, and analysis of the data to establish the causes of the failures. Information on outlet ducts is presented in this paper.

  15. External linkage tie permits reduction in ducting system flange thickness

    NASA Technical Reports Server (NTRS)

    Pfleger, R. O.

    1966-01-01

    External linkage tie reduces flange thickness and increases seal efficiency in high pressure ducting and piping systems. The linkage transmits the pressure separating load to the tube wall behind the flange allowing the flange to support only the seal.

  16. 23. A detailed interior view of the duct and delivery ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. A detailed interior view of the duct and delivery equipment situated in the upper grain conveyor structure of Elevator and Silo Complex B (1932). - Quaker Oats Cereal Factory, Southeast corner of Broadway & Mill Streets, Akron, Summit County, OH

  17. Distal nasolacrimal duct showing the valve of Hasner.

    PubMed

    Mirante, Joseph P; Christmas, Dewey A; Yanagisawa, Eiji

    2014-01-01

    Recognition of the location of the nasolacrimal duct opening is important to prevent its damage while performing an intranasal inferior meatal antrostomy or creating a window transantrally in the inferior meatal wall during a Caldwell-Luc procedure.

  18. Method and apparatus for duct sealing using a clog-resistant insertable injector

    DOEpatents

    Wang, Duo; Modera, Mark P.

    2010-12-14

    A method for forming a duct access region through one side of a previously installed air duct, wherein the air duct has an air flow with an air flow direction by inserting an aerosol injector into a previously installed air duct through the access region. The aerosol injector includes a liquid tube having a liquid tube orifice for ejecting a liquid to be atomized; and a propellant cap. The method is accomplished by aligning the aerosol injector with the direction of air flow in the duct; activating an air flow within the duct; and spraying a sealant through the aerosol injector to seal the duct in the direction of the air flow.

  19. DUCT RETROFIT STRATEGY TO COMPLEMENT A MODULATING FURNACE.

    SciTech Connect

    ANDREWS,J.W.

    2002-10-02

    Some recent work (Walker 2001, Andrews 2002) has indicated that installing a modulating furnace in a conventional duct system may, in many cases, result in a significant degradation in thermal distribution efficiency. The fundamental mechanism was pointed out nearly two decades ago (Andrews and Krajewski 1985). The problem occurs in duct systems that are less-than-perfectly insulated (e.g., R-4 duct wrap) and are located outside the conditioned space. It stems from the fact that when the airflow rate is reduced, as it will be when the modulating furnace reduces its heat output rate, the supply air will have a longer residence time in the ducts and will therefore lose a greater percentage of its heat by conduction than it did at the higher airflow rate. The impact of duct leakage, on the other hand, is not expected to change very much under furnace modulation. The pressures in the duct system will be reduced when the airflow rate is reduced, thus reducing the leakage per unit time. This is balanced by the fact that the operating time will increase in order to meet the same heating load as with the conventional furnace operating at higher output and airflow rates. The balance would be exact if the exponent in the pressure vs. airflow equation were the same as that in the pressure vs. duct leakage equation. Since the pressure-airflow exponent is usually {approx}0.5 and the pressure-leakage exponent is usually {approx}0.6, the leakage loss as a fraction of the load should be slightly lower for the modulating furnace. The difference, however, is expected to be small, determined as it is by a function with an exponent equal to the difference between the above two exponents, or {approx}0.1. The negative impact of increased thermal conduction losses from the duct system may be partially offset by improved efficiency of the modulating furnace itself. Also, the modulating furnace will cycle on and off less often than a single-capacity model, and this may add a small amount

  20. Diagnosis of obstructive jaundice with nondilated bile ducts.

    PubMed

    Muhletaler, C A; Gerlock, A J; Fleischer, A C; James, A E

    1980-06-01

    Obstructive jaundice with nondilated bile ducts was identified by percutaneous transhepatic cholangiography (PTC) in nine of 29 jaundiced patients in whom the etiology of the jaundice was not clearly established by clinical or laboratory means and no dilated ducts were seen at somography or computed tomography (CT). PTC was helpful in these none patients by: (1) differentiating obstructive from nonobstructive jaundice, (2) localizing the site and etiology of the obstructing lesion, and (3) determining operability.

  1. Better Duct Systems for Home Heating and Cooling

    SciTech Connect

    Not Available

    2004-11-01

    Duct systems used in forced-air space-conditioning systems are a vital element in home energy efficiency. How well a system works makes a big difference in the cost and the effectiveness of heating and cooling a home. At the same time, a duct system that is poorly designed or maintained can have a detrimental effect on the health of the people who live in the house, through the unintended distribution of indoor air pollution.

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

    SciTech Connect

    Mallay, D.

    2016-01-01

    A 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.

  3. Beam loss by collimation in a neutralizer duct

    SciTech Connect

    Hamilton, G.W.; Willmann, P.A.

    1980-04-03

    Beam fractions lost by collimation in a neutralizer duct are computed in x-x' phase space by using three examples of slab beam distributions under a broad range of duct dimensions, beam half-widths, and beam divergences. The results can be used to design compact neutralizers and to specify beam requirements. The computer code ILOST can be used under a broad range of beam conditions to compute the fraction lost by collimation.

  4. Symptomatic Mullerian Duct Cyst in a Male Infant.

    PubMed

    Chinya, Abhishek; Raj, Prince; Sinha, Shandip Kumar; Sarin, Yogesh Kumar

    2016-01-01

    Symptomatic Mullerian duct cyst is a rare entity in children. A 9-month-old male infant presented with bowel and urinary obstructive symptoms. Imaging investigations revealed a cystic mass in the rectovesical pouch compressing bladder neck and rectum. At laparotomy, a Mullerian duct cyst was found. Most of the cyst was excised and the remaining cyst mucosa was cauterized. The child improved thereafter. PMID:27672581

  5. Symptomatic Mullerian Duct Cyst in a Male Infant

    PubMed Central

    Chinya, Abhishek; Raj, Prince; Sinha, Shandip Kumar

    2016-01-01

    Symptomatic Mullerian duct cyst is a rare entity in children. A 9-month-old male infant presented with bowel and urinary obstructive symptoms. Imaging investigations revealed a cystic mass in the rectovesical pouch compressing bladder neck and rectum. At laparotomy, a Mullerian duct cyst was found. Most of the cyst was excised and the remaining cyst mucosa was cauterized. The child improved thereafter. PMID:27672581

  6. Female form of persistent mullerian duct syndrome: Rare entity

    PubMed Central

    Solanki, Shailesh; Gowrishankar; Jadhav, Vinay; Babu, M. Narendra; Ramesh, S.

    2015-01-01

    Persistent Mullerian duct syndrome (PMDS) is a rare form of Disorder of sex development in which Mullerian duct derivatives (fallopian tubes, uterus and the proximal vagina) are present in an otherwise normally differentiated 46 XY male. In the majority of cases, PMDS is a surprise finding either during orchidopexy or during inguinal hernia repair. We report a case of 4 year child with female type (Type III) PMDS. We are discussing the presentation, management and review of the literature. PMID:25657558

  7. Female form of persistent mullerian duct syndrome: Rare entity.

    PubMed

    Solanki, Shailesh; Gowrishankar; Jadhav, Vinay; Babu, M Narendra; Ramesh, S

    2015-01-01

    Persistent Mullerian duct syndrome (PMDS) is a rare form of Disorder of sex development in which Mullerian duct derivatives (fallopian tubes, uterus and the proximal vagina) are present in an otherwise normally differentiated 46 XY male. In the majority of cases, PMDS is a surprise finding either during orchidopexy or during inguinal hernia repair. We report a case of 4 year child with female type (Type III) PMDS. We are discussing the presentation, management and review of the literature. PMID:25657558

  8. AIR DUCTS STAND NEXT TO (AND OUTSIDE OF) REACTOR CABINET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AIR DUCTS STAND NEXT TO (AND OUTSIDE OF) REACTOR CABINET AT THE SOUTHWEST AND NORTHEAST CORNERS OF THE REACTOR'S THERMAL SHIELD. THEY WILL BE ENVELOPED IN BIOLOGICAL CONCRETE SHIELD. IN THE SUB-BASEMENT, THE TWO DUCTS WILL JOIN TOGETHER AND EXIT THE BUILDING TO THE FAN HOUSE. CAMERA FACING NORTH. INL NEGATIVE NO. 1625. Unknown Photographer, 3/6/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  9. Acoustic attenuation analysis program for ducts with mean flow

    NASA Technical Reports Server (NTRS)

    Kunze, R. K., Jr.

    1972-01-01

    A computerized acoustic attenuation prediction procedure has been developed to evaluate acoustically lined ducts for various geometric and environmental parameters. The analysis procedure is based on solutions to the acoustic wave equation, assuming uniform airflow on a duct cross section, combined with appropriate mathematical lining impedance models. The impedance models included in the analysis procedure are representative of either perforated sheet or porous polyimide impregnated fiberglass facing sheet coupled with a cellular backing space. Advantages and limitations of the analysis procedure are reviewed.

  10. Asymptomatic Bile Duct Dilatation in Children: Is It a Disease?

    PubMed Central

    Son, Yeo Ju; Lee, Mi Jung; Koh, Hong

    2015-01-01

    Purpose Bile duct dilatation is a relatively common sonographic finding; nevertheless, its clinical significance in children is controversial because little research has been done in the area. Therefore, we investigated the natural course and clinical significance of biliary duct dilatation in children. Methods We performed a retrospective study of 181 children (range, 1-day-old to 17-year-old) in whom dilatation of the intrahepatic duct and/or common hepatic duct and/or common bile duct was detected by abdominal ultrasonography at the Severance Children's Hospital between November 2005 and March 2014. We reviewed and analyzed laboratory test results, clinical manifestations, and clinical course in these patients. Results Pediatric patients (n=181) were enrolled in the study and divided into two groups. The first group included 59 subjects, without definitive cause of bile duct dilatation, who did not require treatment; the second group included 122 subjects, with definitive cause of bile duct dilatation or underlying biliary disease, who did require treatment. In the first group, 24 patients (40.7%) showed spontaneous resolution of bile duct dilatation, 20 patients (33.9%) showed no change, and 15 patients (25.4%) were lost to follow-up. In the second group, 31 patients were diagnosed with choledochal cysts, and 91 patients presented with biliary tract dilatations due to secondary causes, such as gallbladder or liver disease, post-operative complications, or malignancy. Conclusion Biliary dilatation in pediatric patients without symptoms, and without laboratory and other sonographic abnormalities, showed a benign clinical course. No pathologic conditions were noted on follow-up ultrasonography. PMID:26473138

  11. Persistent Mullerian Duct Syndrome with Transverse Testicular Ectopia

    PubMed Central

    Kumar, P. Naresh; Venugopala, Kandgal

    2015-01-01

    Persistent Mullerian duct syndrome (PMDS) is a rare form of male pseudohermaphroditism characterized by the presence of Mullerian duct structures in a normal male with 46, XY karyotype. Transverse testicular ectopia (TTE) is rare form of testicular ectopia in which two testes are located on one inguinal side. The opposite scrotum is empty. PMDS with TTE is rare. We report a case of PMDS with TTE discovered during surgery for a right inguinal hernia in a 25-year-old male. PMID:27512542

  12. Collecting duct carcinoma of the renal medulla presenting with paraplegia.

    PubMed

    Ockrim, J; Tsiriopoulos, I; Rees, H; Mendoza, N; Christmas, T J

    2005-01-01

    We report an interesting case of a patient with collecting duct carcinoma arising from the left kidney who presented with paraplegia secondary to metastases. The diagnosis was based on CT and histology. To our knowledge this is the first case of collecting duct carcinoma to present with paraplegia. The literature review also highlights the rarity of this disease with less than a hundred cases reported to date and the aggressive nature and poor prognosis despite prompt interventions.

  13. Development and regression of the thyroglossal duct in mice.

    PubMed

    Inoue, Katsuyuki; Bando, Yasuhiko; Sakiyama, Koji; Takizawa, Shota; Sakashita, Hideaki; Kondo, Hisatake; Amano, Osamu

    2015-07-01

    The thyroid anlage develops in the foramen caecum area of the tongue, and migrates through the anterior neck towards its final position in front of the laryngeal cartilages. During migration, the thyroglossal duct, a temporary structure connecting the thyroid anlage and the foramen caecum, is recognized. In the present study, chronological changes and apoptosis in the thyroglossal duct of mice were investigated histochemically using an antibody against Nkx2-1, initially identified as a thyroid transcription factor 1 (TTF1), and the TUNEL reaction in consecutive serial sagittal sections. At embryonic day 10.00 (E10.00), the thyroid anlage was Nkx2-1-immunoreactive and located just below the foramen caecum. As the thyroid anlage descended, the thyroglossal duct was formed at E10.25, being less than 10μm in diameter. By E10.75, the Nkx2-1-positive thyroglossal duct had progressively elongated up to 100μm. At E11.00 the thyroglossal duct began to disappear, beginning in its mid-portion, and finally became invisible at E11.50. At E11.00-12.00, apoptotic cells were found in an area where the thyroglossal duct was partially discontinuous. After E12.00, cartilaginous tissue of the hyoid bone anlage developed in the mid-portion of the area where the thyroglossal duct had regressed. Immunoreactivity for thyroglobulin, a marker of differentiated thyroid endocrine cells, was detected at E13.00. These results strongly suggest that the mouse thyroglossal duct disappears as a result of apoptosis before differentiation of the endocrine thyroid.

  14. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1992-01-01

    Condensation heat transfer in an annular flow regime with and without interfacial waves was experimentally investigated. The study included measurements of heat transfer rate with condensation of vapor flowing inside a horizontal rectangular duct and experiments on the initiation of interfacial waves in condensation, and adiabatic air-liquid flow. An analytical model for the condensation was developed to predict condensate film thickness and heat transfer coefficients. Some conclusions drawn from the study are that the condensate film thickness was very thin (less than 0.6 mm). The average heat transfer coefficient increased with increasing the inlet vapor velocity. The local heat transfer coefficient decreased with the axial distance of the condensing surface, with the largest change at the leading edge of the test section. The interfacial shear stress, which consisted of the momentum shear stress and the adiabatic shear stress, appeared to have a significant effect on the heat transfer coefficients. In the experiment, the condensate flow along the condensing surface experienced a smooth flow, a two-dimensional wavy flow, and a three-dimensional wavy flow. In the condensation experiment, the local wave length decreased with the axial distance of the condensing surface and the average wave length decreased with increasing inlet vapor velocity, while the wave speed increased with increasing vapor velocity. The heat transfer measurements are reliable. And, the ultrasonic technique was effective for measuring the condensate film thickness when the surface was smooth or had waves of small amplitude.

  15. WAVE PROPAGATION in the HOT DUCT of VHTR

    SciTech Connect

    Richard Schultz; Jim C. P. Liou

    2013-07-01

    In VHTR, helium from the reactor vessel is conveyed to a power conversion unit through a hot duct. In a hypothesized Depressurized Conduction Cooldown event where a rupture of the hot duct occurs, pressure waves will be initiated and reverberate in the hot duct. A numerical model is developed to quantify the transients and the helium mass flux through the rupture for such events. The flow path of the helium forms a closed loop but only the hot duct is modeled in this study. The lower plum of the reactor vessel and the steam generator are treated as specified pressure and/or temperature boundary to the hot duct. The model is based on the conservation principles of mass, momentum and energy, and on the equations of state for helium. The numerical solution is based on the method of characteristics with specified time intervals with a predictor and corrector algorithm. The rupture sub-model gives reasonable results. Transients induced by ruptures with break area equaling 20%, 10%, and 5% of the duct cross-sectional area are described.

  16. A non-local computational boundary condition for duct acoustics

    NASA Technical Reports Server (NTRS)

    Zorumski, William E.; Watson, Willie R.; Hodge, Steve L.

    1994-01-01

    A non-local boundary condition is formulated for acoustic waves in ducts without flow. The ducts are two dimensional with constant area, but with variable impedance wall lining. Extension of the formulation to three dimensional and variable area ducts is straightforward in principle, but requires significantly more computation. The boundary condition simulates a nonreflecting wave field in an infinite duct. It is implemented by a constant matrix operator which is applied at the boundary of the computational domain. An efficient computational solution scheme is developed which allows calculations for high frequencies and long duct lengths. This computational solution utilizes the boundary condition to limit the computational space while preserving the radiation boundary condition. The boundary condition is tested for several sources. It is demonstrated that the boundary condition can be applied close to the sound sources, rendering the computational domain small. Computational solutions with the new non-local boundary condition are shown to be consistent with the known solutions for nonreflecting wavefields in an infinite uniform duct.

  17. Flow control in a diffusing S-Duct

    NASA Technical Reports Server (NTRS)

    Vakili, A. D.; Wu, J. M.; Liver, P.; Bhat, M. K.

    1985-01-01

    Accurate measurements have been made of secondary flow in a 1.51 area ratio diffusing 30 deg - 30 deg S-Duct with circulair cross section. Turbulent flow was entering the duct at Mach number of 0.6, the boundary layer thickness at the duct entrance was ten percent of the duct inlet diameter. Through measurements made, local flow velocity vector as well as static and total pressures mapping of the flow at several stations were obtained. Strong secondary flow was measured in the first bend which continued into the second bend with new vorticity produced in there in the opposite direction. Surface oil flow visualization and wall pressures indicated a region of separated flow starting at theta approximately equal to 22 deg on the inside of the first bend up to theta approximately equal to 44 deg on the outside of the second bend. The flow separated in 'cyclone' form and never reattached in the duct. As a result of the secondary flow and the flow separation, significant total pressure distortion was observed at the exit of the duct. Using flow control devices the separation was eliminated while the exit distortion was improved.

  18. Numerical study of secondary flows in curved ducts

    SciTech Connect

    Hur, N.

    1988-01-01

    The secondary flow of an incompressible viscous fluid in a curved duct with and without sidewall heating is studied by using a finite-volume method. It is known that for low Dean numbers, the secondary flow is characterized by a pair of counter-rotating vortices. This study shows that, as the Dean number is increased, the secondary-flow structure evolves into a double vortex pair for low-aspect-ratio ducts and roll cells for ducts of high aspect ratio. A stability diagram is obtained in the domain of curvature ratio and Reynolds number. It is found that, for ducts of high curvature, the onset of instability depends on the Dean number and the curvature ratio while, for ducts of small curvature, the onset can be characterized by the Dean number alone. A comparison with the available theoretical and experimental results indicates good agreement. When there is sidewall heating, the interaction between the centrifugal and the buoyancy forces characterizes the secondary flow structure. As the Grashof number is increased, the friction factor can decrease due to the transition from centrifugally dominant flow to buoyancy-dominated flow. Also, for curved ducts the inertial effect dominates and the heat transfer may be enhanced at lower Grashof numbers.

  19. Lymphoepithelial duct lesions in Sjögren-type sialadenitis.

    PubMed

    Ihrler, S; Zietz, C; Sendelhofert, A; Riederer, A; Löhrs, U

    1999-04-01

    It is not clear, whether the so-called basal cells of the salivary striated ducts are an independent cell-type distinct from myoepithelial cells, making characterization of the cell proliferation typical of the duct lesions in Sjögren-type sialadenitis/benign lymphoepithelial lesion (BLEL) difficult. An immunohistochemical investigation including different cytokeratin subtypes, alpha-actin, Ki-67 and Bcl-2 was directed at the epithelial cytoskeleton in normal parotid parenchyma (n=8), BLEL (n=12), HIV-associated lymphoepithelial cysts (n=8) and palatine tonsils (n=8). There are profound morphological and functional differences between basal and myoepithelial cells in the normal salivary duct. Development of duct lesions in BLEL arises from basal cell hyperplasia of striated ducts with aberrant differentiation into a multi-layered and reticulated epithelium, characterized by profound alteration of the cytokeratin pattern. This functionally inferior, metaplastic epithelium is similar to the lymphoepithelial crypt epithelium of palatine tonsils. The often postulated participation of myoepithelial cells in duct lesions of Sjögren disease/BLEL cannot be supported. We regard the designations lymphoepithelial lesion and lymphoepithelial metaplasia as the most appropriate.

  20. Measure Guideline: Summary of Interior Ducts in New Construction, Including an Efficient, Affordable Method to Install Fur-Down Interior Ducts

    SciTech Connect

    Beal, D.; McIlvaine, J.; Fonorow, K.; Martin, E.

    2011-11-01

    This document illustrates guidelines for the efficient installation of interior duct systems in new housing, including the fur-up chase method, the fur-down chase method, and interior ducts positioned in sealed attics or sealed crawl spaces.

  1. THERMAL REGAIN FROM DISPLACEMENT OF DUCT LEAKAGE WITHIN INSULATION.

    SciTech Connect

    ANDREWS,J.W.

    2002-05-01

    In one type of duct efficiency retrofit, additional insulation is added to a duct system that is already insulated. For example, a layer of R-4 insulation might be: added to a duct system that already has R-4 installed. It is possible that--either by chance or by design--the add-on layer, while not stopping duct leaks, might cause the leakage air to flow longitudinally for a distance, parallel to the duct, before it finds a way out of the newly added outer layer. This could happen by chance if the outer and inner layers of insulation have seams at different locations. Perhaps more usefully, if such longitudinal displacement of the leakage air turned out to be useful, it might be designed into the makeup of the outer insulation layer intended to be used in the retrofit. It is plausible that this leakage air might serve a useful function in keeping the insulation layer warmer (or, in the air-conditioning mode, cooler) than it would be in the absence of the leakage. By being held close to the ducts for a while, it might establish an artificially warmer (or cooler, in air conditioning) zone around the ducts. To the extent that this effect would reduce the heat losses from the ducts, the leakage should be credited with a ''thermal regain'' in the same way that leakage into buffer zones is credited with thermal regain when the leakage air warms (or cools) the buffer zone relative to the temperature it would have in the absence of such duct leakage. The purpose of this report is to investigate whether and to what extent such thermal regain exists. The model developed below applies to a situation where there are two distinct layers of insulation around the duct, with leakage air moving between them in a longitudinal direction for a distance before it finds its way out from the outer insulation layer. It may also apply approximately where there is a single insulation layer with an air barrier on the outside. Leakage air may pass into the insulation itself and thence

  2. A comparative study of the differentiation and involution of the Mullerian duct and Wolffian duct in the male and female fetal mouse.

    PubMed

    Dyche, W J

    1979-11-01

    The present investigation has examined the ultrastructural differentiation of the genital ducts of both sexes of fetal mice. The emphasis of observations was placed on the phenomenon of morphogenetic cytolysis, particularly during the critical periods of Wolffian duct stabilization and Mullerian duct involution. Both developing and regressing genital ducts evidence extensive cytolysis. Autophagy appears to be the mechanism of morphogenetic changes in the developing male Wolffian duct. Autophagy, heterophagy, and degeneration in situ are all prominent cytolytic activities in female Wollfian duct involution. The developing female Mullerian duct undergoes extensive morphogenetic remodeling by the mechanisms of autophagy, heterophagy, and degeneration in situ. In the male Mullerian duct, autophagy, heterophagy, and degeneration in situ are also prominent. In addition, whole degenerated epithelial cells are extruded from the duct early in regression which may be realted to the transformation of periductal mesenchymal cells into an "epithelioid cell cuff" which does not form around the regressing Wolffian duct. The formation of this mesenchymal condensation surrounding the duct is also accompanied by the protrusion of Mullerian epithelial cell cytoplasm into the mesenchymal cells. These observations may evidence a complex epithelial-mesenchymal interaction occurring during male Mullerian duct involution.

  3. On the attenuation of sound by three-dimensionally segmented acoustic liners in a rectangular duct

    NASA Technical Reports Server (NTRS)

    Koch, W.

    1979-01-01

    Axial segmentation of acoustically absorbing liners in rectangular, circular or annual duct configurations is a very useful concept for obtaining higher noise attenuation with respect to the bandwidth of absorption as well as the maximum attenuation. As a consequence, advanced liner concepts are proposed which induce a modal energy transfer in both cross-sectional directions to further reduce the noise radiated from turbofan engines. However, these advanced liner concepts require three-dimensional geometries which are difficult to treat theoretically. A very simple three-dimensional problem is investigated analytically. The results show a strong dependence on the positioning of the liner for some incident source modes while the effect of three-dimensional segmentation appears to be negligible over the frequency range considered.

  4. ATP release, generation and hydrolysis in exocrine pancreatic duct cells.

    PubMed

    Kowal, J M; Yegutkin, G G; Novak, I

    2015-12-01

    Extracellular adenosine triphosphate (ATP) regulates pancreatic duct function via P2Y and P2X receptors. It is well known that ATP is released from upstream pancreatic acinar cells. The ATP homeostasis in pancreatic ducts, which secrete bicarbonate-rich fluid, has not yet been examined. First, our aim was to reveal whether pancreatic duct cells release ATP locally and whether they enzymatically modify extracellular nucleotides/sides. Second, we wished to explore which physiological and pathophysiological factors may be important in these processes. Using a human pancreatic duct cell line, Capan-1, and online luminescence measurement, we detected fast ATP release in response to pH changes, bile acid, mechanical stress and hypo-osmotic stress. ATP release following hypo-osmotic stress was sensitive to drugs affecting exocytosis, pannexin-1, connexins, maxi-anion channels and transient receptor potential cation channel subfamily V member 4 (TRPV4) channels, and corresponding transcripts were expressed in duct cells. Direct stimulation of intracellular Ca(2+) and cAMP signalling and ethanol application had negligible effects on ATP release. The released ATP was sequentially dephosphorylated through ecto-nucleoside triphosphate diphosphohydrolase (NTPDase2) and ecto-5'-nucleotidase/CD73 reactions, with respective generation of adenosine diphosphate (ADP) and adenosine and their maintenance in the extracellular medium at basal levels. In addition, Capan-1 cells express counteracting adenylate kinase (AK1) and nucleoside diphosphate kinase (NDPK) enzymes (NME1, 2), which contribute to metabolism and regeneration of extracellular ATP and other nucleotides (ADP, uridine diphosphate (UDP) and uridine triphosphate (UTP)). In conclusion, we illustrate a complex regulation of extracellular purine homeostasis in a pancreatic duct cell model involving: ATP release by several mechanisms and subsequent nucleotide breakdown and ATP regeneration via counteracting nucleotide

  5. ATP release, generation and hydrolysis in exocrine pancreatic duct cells.

    PubMed

    Kowal, J M; Yegutkin, G G; Novak, I

    2015-12-01

    Extracellular adenosine triphosphate (ATP) regulates pancreatic duct function via P2Y and P2X receptors. It is well known that ATP is released from upstream pancreatic acinar cells. The ATP homeostasis in pancreatic ducts, which secrete bicarbonate-rich fluid, has not yet been examined. First, our aim was to reveal whether pancreatic duct cells release ATP locally and whether they enzymatically modify extracellular nucleotides/sides. Second, we wished to explore which physiological and pathophysiological factors may be important in these processes. Using a human pancreatic duct cell line, Capan-1, and online luminescence measurement, we detected fast ATP release in response to pH changes, bile acid, mechanical stress and hypo-osmotic stress. ATP release following hypo-osmotic stress was sensitive to drugs affecting exocytosis, pannexin-1, connexins, maxi-anion channels and transient receptor potential cation channel subfamily V member 4 (TRPV4) channels, and corresponding transcripts were expressed in duct cells. Direct stimulation of intracellular Ca(2+) and cAMP signalling and ethanol application had negligible effects on ATP release. The released ATP was sequentially dephosphorylated through ecto-nucleoside triphosphate diphosphohydrolase (NTPDase2) and ecto-5'-nucleotidase/CD73 reactions, with respective generation of adenosine diphosphate (ADP) and adenosine and their maintenance in the extracellular medium at basal levels. In addition, Capan-1 cells express counteracting adenylate kinase (AK1) and nucleoside diphosphate kinase (NDPK) enzymes (NME1, 2), which contribute to metabolism and regeneration of extracellular ATP and other nucleotides (ADP, uridine diphosphate (UDP) and uridine triphosphate (UTP)). In conclusion, we illustrate a complex regulation of extracellular purine homeostasis in a pancreatic duct cell model involving: ATP release by several mechanisms and subsequent nucleotide breakdown and ATP regeneration via counteracting nucleotide

  6. Parametric study of electromagnetic waves propagating in absorbing curved S ducts

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.

    1989-01-01

    A finite-element Galerkin formulation has been developed to study attenuation of transverse magnetic (TM) waves propagating in two-dimensional S-curved ducts with absorbing walls. In the frequency range where the duct diameter and electromagnetic wave length are nearly equal, the effect of duct length, curvature (duct offset), and absorber wall thickness was examined. For a given offset in the curved duct, the length of the S-duct was found to significantly affect both the absorptive and reflective characteristics of the duct. For a straight and a curved duct with perfect electric conductor terminations, power attenuation contours were examined to determine electromagnetic wall properties associated with maximum input signal absorption. Offset of the S-duct was found to significantly affect the value of the wall permittivity associated with the optimal attenuation of the incident electromagnetic wave.

  7. The Effects of Vortex Ingestion on the Flow in a Diffusing S-duct

    NASA Technical Reports Server (NTRS)

    Wendt, B. J.; Reichert, B. A.

    1994-01-01

    An experimental study of the effects of an ingested vortex on the flowfield of a diffusing S-duct is reported. The vortex is generated through the use of a stationary pinwheel device mounted upstream of the diffusing S-duct. Three test conditions vary the location of the vortex in the duct inlet crossplane. For each condition of ingested vortex, a baseline S-duct and an S-duct with an array of vortex generators is examined. The data taken consist of duct inlet and exit crossplane surveys of velocity and total pressure. Duct surface flow visualization and static pressure are also recorded. The data acquired in these tests are compared to identical S-duct data taken in the absence of the ingested vortex. The ingested vortex is observed to have a strong influence on the flowfield inside (and exiting) the S-duct, but only when the vortex impinges at the inlet crossplane location coincident with the crossplane location of downstream flow separation within the duct. When the ingested vortex impinges at this location it reduces the extent of flowfield separation inside the baseline duct and promotes stronger crossflow in the exit plane of both the baseline duct and the duct with installed vortex generators. This enhanced crossflow also strengthens the vortices shed from the vortex generators. The other impingement locations of the ingested vortex are found to produce little effect on the flowfield of the duct with or without vortex generators.

  8. Validation of the Predicted Circumferential and Radial Mode Sound Power Levels in the Inlet and Exhaust Ducts of a Fan Ingesting Distorted Inflow

    NASA Technical Reports Server (NTRS)

    Koch, L. Danielle

    2012-01-01

    Fan inflow distortion tone noise has been studied computationally and experimentally. Data from two experiments in the NASA Glenn Advanced Noise Control Fan rig have been used to validate acoustic predictions. The inflow to the fan was distorted by cylindrical rods inserted radially into the inlet duct one rotor chord length upstream of the fan. The rods were arranged in both symmetric and asymmetric circumferential patterns. In-duct and farfield sound pressure level measurements were recorded. It was discovered that for positive circumferential modes, measured circumferential mode sound power levels in the exhaust duct were greater than those in the inlet duct and for negative circumferential modes, measured total circumferential mode sound power levels in the exhaust were less than those in the inlet. Predicted trends in overall sound power level were proven to be useful in identifying circumferentially asymmetric distortion patterns that reduce overall inlet distortion tone noise, as compared to symmetric arrangements of rods. Detailed comparisons between the measured and predicted radial mode sound power in the inlet and exhaust duct indicate limitations of the theory.

  9. Effect of herpesvirus infection on pancreatic duct cell secretion

    PubMed Central

    Hegyi, Péter; Ördög, Balázs; Jr, Zoltán Rakonczai; Takács, Tamás; Lonovics, János; Szabolcs, Annamária; Sári, Réka; Tóth, András; Papp, Julius G; Kovács, András Varró Mária K; Gray, Mike A; Argent, Barry E; Boldogköi, Zsolt

    2005-01-01

    AIM: To examine the effect of acute infection caused by herpesvirus (pseudorabies virus, PRV) on pancreatic ductal secretion. METHODS: The virulent Ba-DupGreen (BDG) and non-virulent Ka-RREp0lacgfp (KEG) genetically modified strains of PRV were used in this study and both of them contain the gene for green fluorescent protein (GFP). Small intra/interlobular ducts were infected with BDG virus (107 PFU/mL for 6 h) or with KEG virus (1010 PFU/mL for 6 h), while non-infected ducts were incubated only with the culture media. The ducts were then cultured for a further 18 h. The rate of HCO3- secretion [base efflux -J(B-)] was determined from the buffering capacity of the cells and the initial rate of intracellular acidification (1) after sudden blockage of basolateral base loaders with dihydro-4,4-diisothiocyanatostilbene-2,2-disulfonic acid (500 mmol/L) and amiloride (200 mmol/L), and (2) after alkali loading the ducts by exposure to NH4Cl. All the experiments were performed in HCO3--buffered Ringer solution at 37°C (n = 5 ducts for each experimental condition). Viral structural proteins were visualized by immunohistochemistry. Virally-encoded GFP and immunofluorescence signals were recorded by a confocal laser scanning microscope. RESULTS: The BDG virus infected the majority of accessible cells of the duct as judged by the appearance of GFP and viral antigens in the ductal cells. KEG virus caused a similarly high efficiency of infection. After blockage of basolateral base loaders, BDG infection significantly elevated -J(B-) 24 h after the infection, compared to the non-infected group. However, KEG infection did not modify -J(B-). After alkali loading the ducts, -J(B-) was significantly elevated in the BDG group compared to the control group 24 h after the infection. As we found with the inhibitor stop method, no change was observed in the group KEG compared to the non-infected group. CONCLUSION: Incubation with the BDG or KEG strains of PRV results in an effective

  10. Pc1 propagation in the ionospheric duct: wave vector determination

    NASA Astrophysics Data System (ADS)

    Nomura, Reiko; Glassmeier, Karl-Heinz; Narita, Yasuhito; Plaschke, Fedinand; Mann, Ian

    2013-04-01

    Pc1 geomagnetic pulsations (Pc1) are believed to propagate as fast mode waves in the ionospheric duct. Previous studies tried to locate the Pc1 source region with different methods using the characteristics of the ionospheric duct propagation (e.g., polarization method and amplitude distributions). However, no observational study of the wave vectors and the dispersion relations in the Pc1 source region has been compared with the results estimated from model calculations of the Pc1 ionospheic duct propagation. We have investigated propagation directions of Pc1 pulsations in the ionospheric duct with the 2D Wave Telescope technique. For our study, we used ground-based measurements of Pc1 pulsations from 27 May 2011, observed at 17 different stations of the Canadian magnetometer network CARISMA (www.carisma.ca). These multi-point measurements allow to derive detailed information directly on the wave propagation directions. We also show the dispersion relation of the Pc1 pulsations in the ionospheric duct.

  11. Sensor-based navigation of air duct inspection mobile robots

    NASA Astrophysics Data System (ADS)

    Koh, Kyoungchul; Choi, H. J.; Kim, Jae-Seon; Ko, Kuk Won; Cho, Hyungsuck

    2001-02-01

    12 This paper deals with an image sensor system and its position estimation algorithm for autonomous duct cleaning and inspection mobile robots. For the real application, a hierarchical control structure that consists of robot motion controller and image sensor system is designed considering the efficient and autonomous motion behaviors in narrow space such as air ducts. The sensor's system consists of a CCD camera and two laser sources to generate slit beams. The image of the structured lights is used for calculating the geometric parameters of the air ducts which are usually designed with a rectangular section. With the acquired 3D information about the environment, the mobile robot with two differential driving wheels is able to autonomously navigates along the duct path without any human intervention. For real time navigation, the relative position estimation of the robot are performed from 3D image reconstructed by the sensor system. The calibration and image processing methods used for the sensor system are presented with the experimental data. The experimental results show the possibility of the sensor based navigation which is important for effective duct cleaning by small mobile robots.

  12. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    SciTech Connect

    Beach, R.; Burdick, A.

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance (Rutkowski, H. Manual D -- Residential Duct Systems, 3rd edition, Version 1.00. Arlington, VA: Air Conditioning Contractors of America, 2009.). IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations (Beach, R., Prahl, D., and Lange, R. CFD Analysis of Flexible Duct Junction Box Design. Golden, CO: National Renewable Energy Laboratory, submitted for publication 2013). These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.

  13. Ducts in the Attic? What Were They Thinking? Preprint

    SciTech Connect

    Roberts, D.; Winkler, J.

    2010-08-01

    As energy-efficiency efforts focus increasingly on existing homes, we scratch our heads about construction decisions made 30, 40, 50-years ago and ask: 'What were they thinking?' A logical follow-on question is: 'What will folks think in 2050 about the homes we're building today?' This question can lead to a lively discussion, but the current practice that we find most alarming is placing ducts in the attic. In this paper, we explore through literature and analysis the impact duct location has on cooling load, peak demand, and energy cost in hot climates. For a typical new home in these climates, we estimate that locating ducts in attics rather than inside conditioned space increases the cooling load 0.5 to 1 ton, increases cooling costs 15% and increases demand by 0.75 kW. The aggregate demand to service duct loss in homes built in Houston, Las Vegas, and Phoenix during the period 2000 through 2009 is estimated to be 700 MW. We present options for building homes with ducts in conditioned space and demonstrate that these options compare favorably with other common approaches to achieving electricity peak demand and consumption savings in homes.

  14. High-Performance Ducts in Hot-Dry Climates

    SciTech Connect

    Hoeschele, Marc; Chitwood, Rick; German, Alea; Weitzel, Elizabeth

    2015-07-30

    Duct thermal losses and air leakage have long been recognized as prime culprits in the degradation of heating, ventilating, and air-conditioning (HVAC) system efficiency. Both the U.S. Department of Energy’s Zero Energy Ready Home program and California’s proposed 2016 Title 24 Residential Energy Efficiency Standards require that ducts be installed within conditioned space or that other measures be taken to provide similar improvements in delivery effectiveness (DE). Pacific Gas & Electric Company commissioned a study to evaluate ducts in conditioned space and high-performance attics (HPAs) in support of the proposed codes and standards enhancements included in California’s 2016 Title 24 Residential Energy Efficiency Standards. The goal was to work with a select group of builders to design and install high-performance duct (HPD) systems, such as ducts in conditioned space (DCS), in one or more of their homes and to obtain test data to verify the improvement in DE compared to standard practice. Davis Energy Group (DEG) helped select the builders and led a team that provided information about HPD strategies to them. DEG also observed the construction process, completed testing, and collected cost data.

  15. Hydatid cyst in the duct of the submandibular gland.

    PubMed

    Georgopoulos, S; Korres, S; Riga, M; Kouvidou, Ch; Balatsouras, D; Ferekidis, E

    2007-02-01

    The case of a hydatid cyst located in the duct of Wharton of a 56-year-old farmer is reported not only because of the unusual location of the disease, but also because the clinical manifestations and surgical findings of the hydatid cyst strongly resembled those of a salivary calculus in the duct of Wharton. The patient presented with a non-painful swelling of the right submandibular region. The mass, which appeared 5 years before seeking medical advice, augmented progressively during the first year after its onset and remained stable during the next 4 years. The subsequent surgical excision of the mass was uneventful and a round mass, which was palpated intraoperatively in the duct of Wharton was assumed to be a sialolith. The diagnosis for a hydatid cyst of the duct of Wharton was made by histological examination. Although salivary calculus is the most common finding in cases of obliteration of the duct of Wharton, histological examination of the surgically excised submandibular gland may reveal benign tumours. In extremely rare cases where hydatid cysts are located in the cervicofacial area, a detailed further diagnostic procedure is required in order to diagnose possible involvement of other organs.

  16. Advances in Therapeutic Cholangioscopy

    PubMed Central

    Moura, Renata Nobre; de Moura, Eduardo Guimarães Hourneaux

    2016-01-01

    Nowadays, cholangioscopy is an established modality in diagnostic and treatment of pancreaticobiliary diseases. The more widespread use and the recent development of new technologies and accessories had renewed the interest of endoscopic visualization of the biliary tract, increasing the range of indications and therapeutic procedures, such as diagnostic of indeterminate biliary strictures, lithotripsy of difficult bile duct stones, ablative techniques for intraductal malignancies, removal of foreign bodies and gallbladder drainage. These endoscopic interventions will probably be the last frontier in the near future. This paper presents the new advances in therapeutic cholangioscopy, focusing on the current clinical applications and on research areas. PMID:27403156

  17. Sea trials of a ducted tip propeller designed for improved cavitation performance

    SciTech Connect

    Hordnes, I.; Bidaud, A.; Green, S.I.

    1994-12-31

    Studies have shown that ``ring-wing`` or ``ducted`` tip devices reduce substantially the inception index of trailing vortices generated by a hydrofoil (Green et al. 1988). It has also been shown that these devices improve the lift/drag ratio of an airfoil at high angle of incidence (Duan et al. 1992). These finding indicate that there may be a marine application for the ducted tip. Experimental equipment has been designed and manufactured in preparation for upcoming tests of a propeller with ducted tips. The tips are tubes aligned with the propeller blade tips that will replace a radial fraction of the original blade tips equal to the diameter of the tubes. The tube dimensions have been chosen according to the span/tip diameter and chord/tip length ratios used by Duan et al. (1992), and the tubes will be given a curvature equal to the propeller tip radius. Field trials will be given a curvature equal to the propeller tip radius. Field trials will be conducted on a 36 inch diameter propeller that is used to propel a 45 ft. fishing (seine) boat operating in the coastal waters outside Vancouver. The performance of the propeller will be measured in terms of the propeller efficiency as a function of advance ratio. A special force transducer has been designed that is capable of recording both torque and thrust on the propeller shaft even though these are expected to produce shaft strains of different orders of magnitude. As a supplementary means of monitoring the propeller performance, a hydrophone will be located near the propeller wake in order to measure the tip vortex cavitation noise.

  18. An Exact Transfer Matrix Formulation of Plane Sound Wave Transmission in Inhomogeneous Ducts

    NASA Astrophysics Data System (ADS)

    Dockumaci, E.

    1998-11-01

    The impedance, or the reflection coefficient, of plane sound waves in inhomogeneous ducts satisfies a Riccati equation. The present paper shows that the duct impedance matrix, or the scattering matrix, can be related explicitly to the solutions of the associated linear equation of the Riccati equation for duct impedance, or reflection coefficient, respectively. New exact analytical scattering matrix solutions, which follow as consequences of this connection, are given for two significant duct acoustics problems, namely, the sound transmission in non-uniform ducts carrying an incompressible subsonic low Mach number mean flow transmission of sound in uniform ducts with a full quadratic axial mean temperature gradient.

  19. Thyroglossal duct cyst accompanied by laryngomalacia and pulmonary sequestration.

    PubMed

    Yagasaki, Hideaki; Makino, Koichi; Goto, Yusuke; Suzuki, Takeyuki; Oyachi, Noboru; Obana, Kazuko; Ko, Junichi; Komai, Takayuki

    2014-06-01

    A 2-month-old full-term female infant developed nasal stridor, which progressed to respiratory distress and poor sucking ability. Direct pharyngoscopy showed laryngomalacia and a midline cystic mass in the lingual region. The mass pressed on the epiglottis, causing dyspnea. Computed tomography incidentally revealed extralobar pulmonary sequestration. Direct deroofing of the lingual cyst and plication of the epiglottis were performed at 3 months of age, and the patient recovered from the respiratory distress. Histopathology of the cystic mass showed a thyroglossal duct cyst. Thoracoscopic resection of the pulmonary sequestration was then done at 17 months of age. Thyroglossal duct cysts in the lingual region may cause destabilization of the epiglottis and laryngomalacia, resulting in acquired respiratory obstruction. The combination of thyroglossal duct cyst, laryngomalacia, and pulmonary sequestration is rare; therefore, reports must be accumulated in order to explore the embryological origins of such cases. PMID:24894942

  20. Mode Propagation in Nonuniform Circular Ducts with Potential Flow

    NASA Technical Reports Server (NTRS)

    Cho, Y. C.; Ingard, K. U.

    1982-01-01

    A previously reported closed form solution is expanded to determine effects of isentropic mean flow on mode propagation in a slowly converging-diverging duct, a circular cosh duct. On the assumption of uniform steady fluid density, the mean flow increases the power transmission coefficient. The increase is directly related to the increase of the cutoff ratio at the duct throat. With the negligible transverse gradients of the steady fluid variables, the conversion from one mode to another is negligible, and the power transmission coefficient remains unchanged with the mean flow direction reversed. With a proper choice of frequency parameter, many different modes can be made subject to a single value of the power transmission loss. A systematic method to include the effects of the gradients of the steady fluid variables is also described.

  1. CT diagnosis of an iatrogenic bile duct injury

    PubMed Central

    Mbarushimana, Simon; Morris-Stiff, Gareth; Hassn, Ahmed

    2014-01-01

    Bile duct injuries are a recognised complication of cholecystectomy and a number of options exist for their evaluation. A 44-year-old woman presented with a suspected biliary leak 11 days following an open cholecystectomy. Her medical history was significant for biliopancreatic diversion 2 years previously. An ultrasound scan demonstrated a perihepatic collection but no dilation of the biliary tree was observed. The patient's surgical history and the lack of biliary dilation precluded an endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography, and she could not undergo an MR cholangiopancreatography due to claustrophobia. A CT cholangiogram was performed and clarified the location of the injury, facilitating operative identification and repair of the bile duct. CT cholangiography performed as a dynamic procedure is useful as a means of identifying bile duct injuries. PMID:25267805

  2. Externalized decondensed neutrophil chromatin occludes pancreatic ducts and drives pancreatitis.

    PubMed

    Leppkes, Moritz; Maueröder, Christian; Hirth, Sebastian; Nowecki, Stefanie; Günther, Claudia; Billmeier, Ulrike; Paulus, Susanne; Biermann, Mona; Munoz, Luis E; Hoffmann, Markus; Wildner, Dane; Croxford, Andrew L; Waisman, Ari; Mowen, Kerri; Jenne, Dieter E; Krenn, Veit; Mayerle, Julia; Lerch, Markus M; Schett, Georg; Wirtz, Stefan; Neurath, Markus F; Herrmann, Martin; Becker, Christoph

    2016-03-11

    Ductal occlusion has been postulated to precipitate focal pancreatic inflammation, while the nature of the primary occluding agents has remained elusive. Neutrophils make use of histone citrullination by peptidyl arginine deiminase-4 (PADI4) in contact to particulate agents to extrude decondensed chromatin as neutrophil extracellular traps (NETs). In high cellular density, NETs form macroscopically visible aggregates. Here we show that such aggregates form inside pancreatic ducts in humans and mice occluding pancreatic ducts and thereby driving pancreatic inflammation. Experimental models indicate that PADI4 is critical for intraductal aggregate formation and that PADI4-deficiency abrogates disease progression. Mechanistically, we identify the pancreatic juice as a strong instigator of neutrophil chromatin extrusion. Characteristic single components of pancreatic juice, such as bicarbonate ions and calcium carbonate crystals, induce aggregated NET formation. Ductal occlusion by aggregated NETs emerges as a pathomechanism with relevance in a plethora of inflammatory conditions involving secretory ducts.

  3. Externalized decondensed neutrophil chromatin occludes pancreatic ducts and drives pancreatitis

    PubMed Central

    Leppkes, Moritz; Maueröder, Christian; Hirth, Sebastian; Nowecki, Stefanie; Günther, Claudia; Billmeier, Ulrike; Paulus, Susanne; Biermann, Mona; Munoz, Luis E.; Hoffmann, Markus; Wildner, Dane; Croxford, Andrew L.; Waisman, Ari; Mowen, Kerri; Jenne, Dieter E.; Krenn, Veit; Mayerle, Julia; Lerch, Markus M.; Schett, Georg; Wirtz, Stefan; Neurath, Markus F.; Herrmann, Martin; Becker, Christoph

    2016-01-01

    Ductal occlusion has been postulated to precipitate focal pancreatic inflammation, while the nature of the primary occluding agents has remained elusive. Neutrophils make use of histone citrullination by peptidyl arginine deiminase-4 (PADI4) in contact to particulate agents to extrude decondensed chromatin as neutrophil extracellular traps (NETs). In high cellular density, NETs form macroscopically visible aggregates. Here we show that such aggregates form inside pancreatic ducts in humans and mice occluding pancreatic ducts and thereby driving pancreatic inflammation. Experimental models indicate that PADI4 is critical for intraductal aggregate formation and that PADI4-deficiency abrogates disease progression. Mechanistically, we identify the pancreatic juice as a strong instigator of neutrophil chromatin extrusion. Characteristic single components of pancreatic juice, such as bicarbonate ions and calcium carbonate crystals, induce aggregated NET formation. Ductal occlusion by aggregated NETs emerges as a pathomechanism with relevance in a plethora of inflammatory conditions involving secretory ducts. PMID:26964500

  4. Endoscopic management of difficult common bile duct stones

    PubMed Central

    Trikudanathan, Guru; Navaneethan, Udayakumar; Parsi, Mansour A

    2013-01-01

    Endoscopy is widely accepted as the first treatment option in the management of bile duct stones. In this review we focus on the alternative endoscopic modalities for the management of difficult common bile duct stones. Most biliary stones can be removed with an extraction balloon, extraction basket or mechanical lithotripsy after endoscopic sphincterotomy. Endoscopic papillary balloon dilation with or without endoscopic sphincterotomy or mechanical lithotripsy has been shown to be effective for management of difficult to remove bile duct stones in selected patients. Ductal clearance can be safely achieved with peroral cholangioscopy guided laser or electrohydraulic lithotripsy in most cases where other endoscopic treatment modalities have failed. Biliary stenting may be an alternative treatment option for frail and elderly patients or those with serious co morbidities. PMID:23345939

  5. [Postoperative handling in biliodigestive derivation by iatrogenic bile duct injury].

    PubMed

    Domínguez, I; Mercado, M A

    2008-01-01

    Bile duct injury is a severe complication related to cholecystectomy, impacting in the long-term quality of life and functional status. Bile duct repair is the first-line treatment for complex injuries. During short-term and long-term postoperative care, it is important to bear in mind the diagnostic tools, both laboratory and imaging, that will be useful to evaluate a possible surgical complication and to plan an adequate therapeutic strategy. In addition, post-surgical classification describes patients according to their complications and clinical course. In this review we describe the principal issues of postoperative care after bile duct repair, highlighting the diagnosis, severity classification and therapeutic approach of acute cholangitis.

  6. [Intraoperative ultrasonography for common bile duct exploration during laparoscopic cholecystectomy].

    PubMed

    Bende, Sándor; Botos, Akos; Ottlakán, Aurél; Pásztor, Pál; Pálfi, Attila; Liptay-Wagner, Péter

    2003-12-01

    The "Endomedix Laparoscan" and the "Leopard" and "Panther" intraoperative ultrasounds were successfully used for the detection of unsuspected common bile duct stones during laparoscopic cholecystectomy (LC). Out of 60 patients six had common bile duct (CBD) stones and in one patient sludge has been seen. In patients with CBD stones, four small calculi have been observed in one patient, despite negative intraoperative cholangiography (IC). In an other patient a stone in the retropancreatic part of the CBD was detected. Based on preoperative findings CBD stone was unsuspected. We found that intraoperative ultrasound (IOUS) is useful for in investigating the CBD to detect unsuspected common bile duct stones. It can be used for the examination of other organs (liver, pancreas, hepatoduodenal ligament) as well. The method is easy to perform, fairly simple and informative so it can replace IC during laparoscopic cholecystectomy.

  7. Observationally constrained modeling of sound in curved ocean internal waves: examination of deep ducting and surface ducting at short range.

    PubMed

    Duda, Timothy F; Lin, Ying-Tsong; Reeder, D Benjamin

    2011-09-01

    A study of 400 Hz sound focusing and ducting effects in a packet of curved nonlinear internal waves in shallow water is presented. Sound propagation roughly along the crests of the waves is simulated with a three-dimensional parabolic equation computational code, and the results are compared to measured propagation along fixed 3 and 6 km source/receiver paths. The measurements were made on the shelf of the South China Sea northeast of Tung-Sha Island. Construction of the time-varying three-dimensional sound-speed fields used in the modeling simulations was guided by environmental data collected concurrently with the acoustic data. Computed three-dimensional propagation results compare well with field observations. The simulations allow identification of time-dependent sound forward scattering and ducting processes within the curved internal gravity waves. Strong acoustic intensity enhancement was observed during passage of high-amplitude nonlinear waves over the source/receiver paths, and is replicated in the model. The waves were typical of the region (35 m vertical displacement). Two types of ducting are found in the model, which occur asynchronously. One type is three-dimensional modal trapping in deep ducts within the wave crests (shallow thermocline zones). The second type is surface ducting within the wave troughs (deep thermocline zones).

  8. CASE STUDY OF DUCT RETROFIT OF A 1985 HOME AND GUIDELINES FOR ATTIC AND CRAWL SPACE DUCT SEALING

    SciTech Connect

    Boudreaux, Philip R; Christian, Jeffrey E; Jackson, Roderick K

    2012-01-01

    The U.S. Department of Energy (DOE) is fully committed to research for developing the information and capabilities necessary to provide cost-effective residential retrofits yielding 50% energy savings within the next several years. Heating, ventilation, and air conditioning (HVAC) is the biggest energy end use in the residential sector, and a significant amount of energy can be wasted through leaky ductwork in unconditioned spaces such as attics and crawl spaces. A detailed duct sealing case study is presented for one house along with nine brief descriptions of other duct retrofits completed in the mixed-humid climate. Costs and estimated energy savings are reported for most of the ten houses. Costs for the retrofits ranged from $0.92/ft2 to $1.80/ft2 of living space and estimated yearly energy cost savings due to the duct retrofits range from 1.8% to 18.5%. Lessons learned and duct sealing guidelines based on these ten houses, as well as close work with the HVAC industry in the mixed-humid climate of East Tennessee, northern Georgia, and south-central Kentucky are presented. It is hoped that the lessons learned and guidelines will influence local HVAC contractors, energy auditors, and homeowners when diagnosing or repairing HVAC duct leakage and will be useful for steering DOE s future research in this area.

  9. Salivary duct carcinoma (cribriform salivary carcinoma of excretory ducts). A clinicopathologic and immunohistochemical study of 12 cases.

    PubMed

    Brandwein, M S; Jagirdar, J; Patil, J; Biller, H; Kaneko, M

    1990-05-15

    Salivary duct carcinoma (cribriform salivary carcinoma of the excretory ducts [CSCED]) is an uncommon malignant tumor which occurs predominantly in men (83% in this series; mean age, 61 years) and most often in the parotid gland (92% in this series). The outcome is unfavorable for most patients; of 11 of 12 patients with follow-up, 45% had local recurrence, 54% had distant metastasis, and 45% were dead of disease within 10 years of diagnosis (mean, 3 years). Metastases to lymph nodes were common (72%). Immunohistochemical studies on paraffin-embedded tissue revealed that most tumors reacted with antibodies known to mark adenocarcinoma: B72.3 (11 of 11) and Lewis Y (ten of ten). High and low molecular weight cytokeratins were present in most tumors (nine of ten and seven of nine cases, respectively), supporting the concept that these adenocarcinomas were of ductal origin. Parotid ducts adjacent to CSCED expressed B72.3 in six of nine cases studied, but parotid ducts from normal tissue (adjacent to benign mixed tumors or enlarged periparotid lymph nodes) rarely expressed this marker (one of 17 cases). The detection of B72.3 diffusely in parotid ducts, especially those with atypia, may imply the presence of malignant tumor nearby, which could be useful in evaluating limited tissue from the parotid. However, further studies are necessary to confirm the significance of this finding.

  10. Moulded calculus of common bile duct mimicking a stenosis

    PubMed Central

    Brocki, Marian; Śmigielski, Jacek

    2014-01-01

    Bile duct stenosis, in most cases, appears to be the consequence of pancreatic head, ampulla of Vater and bile duct tumours, cholangitis sclerosans, as well as iatrogenic damages, which may all be diagnosed during endoscopic retrograde cholangiopancreatography (ERCP). In very rare cases the restriction may result from an atypically shaped wedged stone. This situation creates many diagnostic problems, which in the majority of cases can be solved using imaging studies. However, in some patients even a significant extension of diagnostic procedures may not lead to a correct diagnosis. We present a diagnostically difficult case of a deposit imitating restriction. We present a 70-year-old woman with common bile duct restriction undiagnosed despite several ultrasound examinations (USG), computed tomography (CT), double magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP). Only after the third ERCP examination a fragmented, by formerly introduced prosthesis, deposit, imitating narrowing, was revealed. Identification of bile duct deposits depends on their composition, localisation and the imaging techniques used. Pigment calculi with atypical shape, bile density, air density or surrounding tissue density are very difficult to diagnose. Thus, the sensitivity of common bile duct stone detection in USG, CT, MRCP and endoscopic ultrasound (EUS) is 5–88%; 6–88%; 73–97%; and 84–98%, respectively. Moreover, ERCP may not diagnose the character of the restriction even in 5.2% up to 30% of the patients. Consequently, assessment of diagnosis in a number of patients is difficult. A deposit imitating common bile duct (CBD) restriction is a rare, difficult to diagnose phenomenon, which should be taken into account during differential diagnosis of CBD restrictions. PMID:25061493

  11. Bundle duct interaction studies for fuel assemblies. [LMFBR

    SciTech Connect

    Hsia, H.T.S.; Kaplan, S.

    1981-06-01

    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.

  12. Whistler propagation in ionospheric density ducts: Simulations and DEMETER observations

    NASA Astrophysics Data System (ADS)

    Woodroffe, J. R.; Streltsov, A. V.; Vartanyan, A.; Milikh, G. M.

    2013-11-01

    On 16 October 2009, the Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite observed VLF whistler wave activity coincident with an ionospheric heating experiment conducted at HAARP. At the same time, density measurements by DEMETER indicate the presence of multiple field-aligned enhancements. Using an electron MHD model, we show that the distribution of VLF power observed by DEMETER is consistent with the propagation of whistlers from the heating region inside the observed density enhancements. We also discuss other interesting features of this event, including coupling of the lower hybrid and whistler modes, whistler trapping in artificial density ducts, and the interference of whistlers waves from two adjacent ducts.

  13. Fundamental investigation of duct/ESP phenomena. Final report

    SciTech Connect

    Brown, C.A.; Durham, M.D.; Sowa, W.A.; Himes, R.M.; Mahaffey, W.A.

    1991-10-21

    Radian Corporation was contracted to investigate duct injection and ESP phenomena in a 1.7 MW pilot plant constructed for this test program. This study was an attempt to resolve problems found in previous studies and answer remaining questions for the technology using an approach which concentrates on the fundamental mechanisms of the process. The goal of the study was to obtain a better understanding of the basic physical and chemical phenomena that control: (1) the desulfurization of flue gas by calcium-based reagent, and (2) the coupling of an existing ESP particulate collection device to the duct injection process. Process economics are being studied by others. (VC)

  14. A numerical investigation of primary surface rounded cross wavy ducts

    NASA Astrophysics Data System (ADS)

    Utriainen, E.; Sundén, B.

    A three-dimensional numerical study was conducted to assess the hydraulic and heat transfer performance of primary surface type heat exchanger surfaces, called cross wavy (CW) ducts aimed for recuperators. The governing equations, i.e., the mass conservation equation, Navier-Stokes equations and the energy equation, are solved numerically by a finite volume method for boundary fitted coordinates. Periodic boundary conditions are imposed in the main flow direction. In this particular case laminar convective flow and heat transfer prevail. Details of the recuperator ducts and the numerical method as well as relevant results are presented.

  15. Case report of giant sialolith (megalith) of the Wharton's duct.

    PubMed

    Omezli, M M; Ayranci, F; Sadik, E; Polat, M E

    2016-01-01

    Sialolithiasis is the most common disease of salivary glands. Its estimated frequency is 1.2% in the adult population. Sialoliths most commonly occur in the submandibular glands. The sublingual gland and minor salivary glands are rarely affected. The sialolith usually measures from 1 to <10 mm. Giant sialoliths are classified as those exceeding 15 mm in any one dimension. In literature, large sialoliths or megalith (> mm) of Wharton's duct have rarely been reported. This case report describes a patient presenting with an unusually large sialolith (megalith) of Wharton's duct, which was 37 mm ×16 mm in the size, the subsequent patient management, the etiology, diagnosis, and its treatment. PMID:27022811

  16. Sound propagation through a variable area duct - Experiment and theory

    NASA Technical Reports Server (NTRS)

    Silcox, R. J.; Lester, H. C.

    1981-01-01

    A comparison of experiment and theory has been made for the propagation of sound through a variable area axisymmetric duct with zero mean flow. Measurement of the acoustic pressure field on both sides of the constricted test section was resolved on a modal basis for various spinning mode sources. Transmitted and reflected modal amplitudes and phase angles were compared with finite element computations. Good agreement between experiment and computation was obtained over a wide range of frequencies and modal transmission variations. The study suggests that modal transmission through a variable area duct is governed by the throat modal cut-off ratio.

  17. Development of a Training Model for Laparoscopic Common Bile Duct Exploration

    PubMed Central

    Rodríguez, Omaira; Benítez, Gustavo; Sánchez, Renata; De la Fuente, Liliana

    2010-01-01

    Background: Training and experience of the surgical team are fundamental for the safety and success of complex surgical procedures, such as laparoscopic common bile duct exploration. Methods: We describe an inert, simple, very low-cost, and readily available training model. Created using a “black box” and basic medical and surgical material, it allows training in the fundamental steps necessary for laparoscopic biliary tract surgery, namely, (1) intraoperative cholangiography, (2) transcystic exploration, and (3) laparoscopic choledochotomy, and t-tube insertion. Results: The proposed model has allowed for the development of the skills necessary for partaking in said procedures, contributing to its development and diminishing surgery time as the trainee advances down the learning curve. Further studies are directed towards objectively determining the impact of the model on skill acquisition. Conclusion: The described model is simple and readily available allowing for accurate reproduction of the main steps and maneuvers that take place during laparoscopic common bile duct exploration, with the purpose of reducing failure and complications. PMID:20529526

  18. Far-field noise and internal modes from a ducted propeller at simulated aircraft takeoff conditions

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Bock, Lawrence A.; Heidelberg, Laurence J.; Hall, David G.

    1992-01-01

    The ducted propeller offers structural and acoustic benefits typical of conventional turbofan engines while retaining much of the aeroacoustic benefits of the unducted propeller. A model Advanced Ducted Propeller (ADP) was tested in the NASA Lewis Low-Speed Anechoic Wind Tunnel at a simulated takeoff velocity of Mach 0.2. The ADP model was designed and manufactured by the Pratt and Whitney Division of United Technologies. The 16-blade rotor ADP was tested with 22- and 40-vane stators to achieve cut-on and cut-off criterion with respect to propagation of the fundamental rotor-stator interaction tone. Additional test parameters included three inlet lengths, three nozzle sizes, two spinner configurations, and two rotor rub strip configurations. The model was tested over a range of rotor blade setting angles and propeller axis angles-of-attack. Acoustic data were taken with a sideline translating microphone probe and with a unique inlet microphone probe which identified inlet rotating acoustic modes. The beneficial acoustic effects of cut-off were clearly demonstrated. A 5 dB fundamental tone reduction was associated with the long inlet and 40-vane sector, which may relate to inlet propeller axis angle-of-attack at rotor speeds of at least 96 percent design.

  19. Investigation of the tone-burst tube for duct lining attenuation measurement

    NASA Technical Reports Server (NTRS)

    Soffel, A. R.; Morrow, P. F.

    1972-01-01

    The tone burst technique makes practical the laboratory evaluation of potential inlet and discharge duct treatments. Tone burst apparatus requires only simple machined parts and standard components. Small, simply made, lining samples are quickly and easily installed in the system. Two small electromagnetric loudspeaker drivers produce peak sound pressure level of over 166 db in the 3-square-inch sample duct. Air pump available in most laboratories can produce air flows of over plus and minus Mach 0.3 in the sample duct. The technique uses short shaped pulses of sound propagated down a progressive wave tube containing the sample duct. The peak pressure level output of the treated duct is compared with the peak pressure level output of a substituted reference duct. The difference between the levels is the attenuation or insertion loss of the treated duct. Evaluations of resonant absorber linings by the tone burst technique check attenuation values predicted by empirical formulas based on full scale ducts.

  20. Effect of flow on the acoustic resonances of an open-ended duct

    NASA Technical Reports Server (NTRS)

    Ingard, U.; Singhal, V. K.

    1975-01-01

    The effect of flow on the acoustic resonances of an open-ended, hard-walled duct is analyzed. The flow produces acoustic losses both in the interior of the duct and at the ends. Unless the duct is very long, typically 100 times the diameter, the losses at the ends dominate. At flow Mach numbers in excess of 0.4 the losses are so large that axial duct resonances are almost completely suppressed. The plane-wave Green's function for the duct with flow is expressed in terms of the (experimentally determined) pressure reflection coefficients at the ends of the duct, and the flow dependence of the complex eigenfrequencies of the duct is obtained. Some observations concerning the noise produced by the flow in the duct are also reported.

  1. Building America Top Innovations 2012: Integration of HVAC System Design with Simplified Duct Distribution

    SciTech Connect

    none,

    2013-01-01

    This Building America Top Innovations profile describes work by Building America research teams who field tested simplified duct designs in hundreds of homes, confirming the performance of short compact duct runs, with supply registers near interior walls.

  2. Building America Top Innovations 2013 Profile – Buried and Encapsulated Ducts

    SciTech Connect

    none,

    2013-09-01

    In this innovation profile, CARB research shows HVAC ducts that are encapsulated in closed-cell spray foam and buried in blown insulation in a vented attic meet the code requirements for ducts in conditioned space.

  3. Installation effects on the production of blade-vortex interaction noise by a ducted rotor

    NASA Astrophysics Data System (ADS)

    Howe, M. S.

    1992-07-01

    An analysis is made of the sound produced when discrete vortices and mean flow turbulence interact at low Mach number with a blade of a ducted rotor situated near the open end of the duct. The duct is rigid and of circular cross-section, and the blade chord is assumed to be small relative to the diameter of the duct. The variation of the amplitude and frequency dependence of the sound with the distance of the blade from the duct exit is examined. For short ducts operating at Mach numbers characteristic of those in underwater applications, it is shown that the acoustic power is increased over a range of frequencies when the rotor plane is close to the exit. For longer ducts, in which the turbulence is fully developed, the influence of the exit is predicted to be negligible when the distance of the rotor plane from the open end exceeds about one-tenth of the duct diameter.

  4. ASSESSMENT OF FUNGAL (PENICILLIUM CHRYSOGENUM) GROWTH ON THREE HVAC DUCT MATERIALS

    EPA Science Inventory

    The article discusses laboratory experiments to evaluate the susceptibility of three ventilation duct materials (fibrous glass ductboard, galvanized steel, and insulated flexible duct) to fungal (P. chrysogenum) growth. [NOTE: Many building investigators have documented fungal bi...

  5. Minimum airflow reset of single-duct VAV terminal boxes

    NASA Astrophysics Data System (ADS)

    Cho, Young-Hum

    Single duct Variable Air Volume (VAV) systems are currently the most widely used type of HVAC system in the United States. When installing such a system, it is critical to determine the minimum airflow set point of the terminal box, as an optimally selected set point will improve the level of thermal comfort and indoor air quality (IAQ) while at the same time lower overall energy costs. In principle, this minimum rate should be calculated according to the minimum ventilation requirement based on ASHRAE standard 62.1 and maximum heating load of the zone. Several factors must be carefully considered when calculating this minimum rate. Terminal boxes with conventional control sequences may result in occupant discomfort and energy waste. If the minimum rate of airflow is set too high, the AHUs will consume excess fan power, and the terminal boxes may cause significant simultaneous room heating and cooling. At the same time, a rate that is too low will result in poor air circulation and indoor air quality in the air-conditioned space. Currently, many scholars are investigating how to change the algorithm of the advanced VAV terminal box controller without retrofitting. Some of these controllers have been found to effectively improve thermal comfort, indoor air quality, and energy efficiency. However, minimum airflow set points have not yet been identified, nor has controller performance been verified in confirmed studies. In this study, control algorithms were developed that automatically identify and reset terminal box minimum airflow set points, thereby improving indoor air quality and thermal comfort levels, and reducing the overall rate of energy consumption. A theoretical analysis of the optimal minimum airflow and discharge air temperature was performed to identify the potential energy benefits of resetting the terminal box minimum airflow set points. Applicable control algorithms for calculating the ideal values for the minimum airflow reset were developed and

  6. Measure Guideline: Summary of Interior Ducts in New Construction, Including an Efficient, Affordable Method to Install Fur-Down Interior Ducts

    SciTech Connect

    Beal, D.; McIlvaine , J.; Fonorow, K.; Martin, E.

    2011-11-01

    This document illustrates guidelines for the efficient installation of interior duct systems in new housing, including the fur-up chase method, the fur-down chase method, and interior ducts positioned in sealed attics or sealed crawl spaces. This document illustrates guidelines for the efficient installation of interior duct systems in new housing. Interior ducts result from bringing the duct work inside a home's thermal and air barrier. Architects, designers, builders, and new home buyers should thoroughly investigate any opportunity for energy savings that is as easy to implement during construction, such as the opportunity to construct interior duct work. In addition to enhanced energy efficiency, interior ductwork results in other important advantages, such as improved indoor air quality, increased system durability and increased homeowner comfort. While the advantages of well-designed and constructed interior duct systems are recognized, the implementation of this approach has not gained a significant market acceptance. This guideline describes a variety of methods to create interior ducts including the fur-up chase method, the fur-down chase method, and interior ducts positioned in sealed attics or sealed crawl spaces. As communication of the intent of an interior duct system, and collaboration on its construction are paramount to success, this guideline details the critical design, planning, construction, inspection, and verification steps that must be taken. Involved in this process are individuals from the design team; sales/marketing team; and mechanical, insulation, plumbing, electrical, framing, drywall and solar contractors.

  7. False-positive radionuclide hepatobiliary imaging following cystic duct stone removal

    SciTech Connect

    Zagoria, R.J.; Cowan, R.J.; Dyer, R.B.; Herrera, M.

    1989-03-01

    The authors report a case in which a radionuclide hepatobiliary image was falsely indicative of cystic duct obstruction in a patient with an indwelling cholecystostomy tube and an externalized gallbladder-duodenal stent. Cystic duct patency was demonstrated radiographically shortly before and after the radionuclide study. The authors recommend that cystic duct obstruction indicated by a radionuclide hepatobiliary image be confirmed by another means if a cholecystostomy tube is present, or if the patient recently has undergone percutaneous gallbladder or cystic duct manipulations.

  8. On the propagation of long waves in acoustically treated, curved ducts

    NASA Technical Reports Server (NTRS)

    Rostafinski, W.

    1981-01-01

    A two dimensional study is presented on the behavior of long waves in lined, curved ducts. The analysis includes a comparison between the propagation in curved and straight lined ducts. A parametric study was conducted over a range of wall admittance and duct wall separation. The complex eigenvalues of the characteristic equation, which in the case of a curved duct are also the angular wavenumbers, were obtained by successive approximations.

  9. Conceptual design study of advanced acoustic-composite nacelles

    NASA Technical Reports Server (NTRS)

    Nordstrom, K. E.; Marsh, A. H.; Sargisson, D. F.

    1975-01-01

    Conceptual studies were conducted to assess the impact of incorporating advanced technologies in the nacelles of a current wide-bodied transport and an advanced technology transport. The improvement possible in the areas of fuel consumption, flyover noise levels, airplane weight, manufacturing costs, and airplane operating cost were evaluated for short and long-duct nacelles. Use of composite structures for acoustic duct linings in the fan inlet and exhaust ducts was considered as well as for other nacelle components. For the wide-bodied transport, the use of a long-duct nacelle with an internal mixer nozzle in the primary exhaust showed significant improvement in installed specific fuel consumption and airplane direct operating costs compared to the current short-duct nacelle. The long-duct mixed-flow nacelle is expected to achieve significant reductions in jet noise during takeoff and in turbo-machinery noise during landing approach. Recommendations were made of the technology development needed to achieve the potential fuel conservation and noise reduction benefits.

  10. Analytical study of flow phenomena in SSME turnaround duct geometries

    NASA Astrophysics Data System (ADS)

    McLallin, K. L.

    1985-04-01

    The SSME fuel turbopump hot gas manifold was identified as a source of loss and flow distortion which significantly affects the performance and durability of both the drive turbine and the LOX injector area of the main combustion chamber. Two current SSME geometries were studied, the full power level (FPL) and the first manned orbital flight (FMOF) configuration. The effects of turnaround duct geometry on flow losses and distortions, by varying wall curvature and flow area variation in the 180 deg turnaround region were examined. The effects of the duct inlet flow phenomena such as the radial distortion of the inlet flow and inlet swirl level on turnaround duct performance were also investigated. It is shown that of the two current geometries, the FMOF configuration had lower pressure losses and generated less flow distortion, but had a small flow separation bubble at the 180 deg turnaround exit. It is found that by optimizing wall curvature and flow diffusion in the turnaround, improved duct performance can be achieved.

  11. Application of computational fluid dynamics to complex inlet ducts

    NASA Astrophysics Data System (ADS)

    Towne, C. E.; Schum, E. F.

    A three-dimensional parabolic Navier-Stokes code, PEPSIG, was used to analyze the flow in the subsonic diffuser section of a typical modern inlet design. The effect of curvature of the diffuser centerline and transitioning cross sections was studied to determine the primary cause of flow distortion in the duct. Total pressure values at the engine compressor face are reported.

  12. Perturbations From Ducts on the Modes of Acoustic Thermometers

    PubMed Central

    Gillis, K. A.; Lin, H.; Moldover, M. R.

    2009-01-01

    We examine the perturbations of the modes of an acoustic thermometer caused by circular ducts used either for gas flow or as acoustic waveguides coupled to remote transducers. We calculate the acoustic admittance of circular ducts using a model based on transmission line theory. The admittance is used to calculate the perturbations to the resonance frequencies and half-widths of the modes of spherical and cylindrical acoustic resonators as functions of the duct’s radius, length, and the locations of the transducers along the duct's length. To verify the model, we measured the complex acoustic admittances of a series of circular tubes as a function of length between 200 Hz and 10 kHz using a three-port acoustic coupler. The absolute magnitude of the specific acoustic admittance is approximately one. For a 1.4 mm inside-diameter, 1.4 m long tube, the root mean square difference between the measured and modeled specific admittances (both real and imaginary parts) over this frequency range was 0.018. We conclude by presenting design considerations for ducts connected to acoustic thermometers. PMID:27504227

  13. Aztreonam biliary excretion in bile duct ligated jaundiced rats.

    PubMed

    Rulli, F; Muzi, M; Zanella, E; Cipriani, P; Magni, A; Giordano, A; Filadoro, F

    1991-04-01

    An experimental study was undertaken to assess aztreonam biliary concentrations in bile duct ligated jaundiced rats. The study proved that aztreonam biliary concentrations are sufficient to inhibit Gram-negative bacteria within the first and the second hour after antibiotic administration. The experimental model suggests that clinical conditions such as lithiasis or neoplasms of the biliary tree should not totally inhibit the antibiotic excretion.

  14. Node retraction during patterning of the urinary collecting duct system.

    PubMed

    Lindström, Nils O; Chang, C-Hong; Valerius, M Todd; Hohenstein, Peter; Davies, Jamie A

    2015-01-01

    This report presents a novel mechanism for remodelling a branched epithelial tree. The mouse renal collecting duct develops by growth and repeated branching of an initially unbranched ureteric bud: this mechanism initially produces an almost fractal form with young branches connected to the centre of the kidney via a sequence of nodes (branch points) distributed widely throughout the developing organ. The collecting ducts of a mature kidney have a different form: from the nephrons in the renal cortex, long, straight lengths of collecting duct run almost parallel to one another through the renal medulla, and open together to the renal pelvis. Here we present time-lapse studies of E11.5 kidneys growing in culture: after about 5 days, the collecting duct trees show evidence of 'node retraction', in which the node of a 'Y'-shaped branch moves downwards, shortening the stalk of the 'Y', lengthening its arms and narrowing their divergence angle so that the 'Y' becomes a 'V'. Computer simulation suggests that node retraction can transform a spread tree, like that of an early kidney, into one with long, almost-parallel medullary rays similar to those seen in a mature real kidney. PMID:25292187

  15. 22. A closeup interior view of the duct work and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. A close-up interior view of the duct work and mechanical equipment used in the delivery of the grain to the upper level grain conveyor system for Elevator and Silo Complex B (1932). - Quaker Oats Cereal Factory, Southeast corner of Broadway & Mill Streets, Akron, Summit County, OH

  16. Imaging of the pancreatic duct by linear endoscopic ultrasound

    PubMed Central

    Sharma, Malay; Rai, Praveer; Rameshbabu, Chittapuram Srinivasan; Arya, Shalini

    2015-01-01

    The current gold standard investigation for anatomic exploration of the pancreatic duct (PD) is endoscopic retrograde cholangiopancreatography. Magnetic resonance cholangiopancreatography is a noninvasive method for exploration of the PD. A comprehensive evaluation of the course of PD and its branches has not been described by endoscopic ultrasound (EUS). In this article, we describe the techniques of imaging of PD using linear EUS. PMID:26374577

  17. Should You Have the Air Ducts in Your Home Cleaned?

    MedlinePlus

    ... heat exchangers) may improve the efficiency of your system, resulting in a longer operating life, as well as some energy and maintenance ... spraying or otherwise introducing these materials into the operating duct system may cause much of the material to be ...

  18. 63. Historic detail drawing of inlet duct cone on exhaust ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    63. Historic detail drawing of inlet duct cone on exhaust scrubber at building 202, June 18, 1955. NASA GRC drawing no. CD-101266. (On file at NASA Glenn Research Center). - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  19. FET. Exhaust duct and stack. Plan, elevation, foundation, details. Ralph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FET. Exhaust duct and stack. Plan, elevation, foundation, details. Ralph M. Parsons 1480-10 ANP/GE-5-716-S-3. Date: February 1959. Approved by INEEL Classification Office for public release. INEEL index code no. 036-0716-00-693-107474 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  20. 24. AIRCONDITIONING DUCT, WINCH CONTROL BOX, AND SPEAKER AT STATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. AIR-CONDITIONING DUCT, WINCH CONTROL BOX, AND SPEAKER AT STATION 85.5 OF MST. FOLDED-UP PLATFORM ON RIGHT OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  1. 29. DETAIL OF OUTLET DUCTS FOR MST AIRCONDITIONING SYSTEM IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. DETAIL OF OUTLET DUCTS FOR MST AIR-CONDITIONING SYSTEM IN NORTHWEST CORNER OF SLC-3W MST STATION 70.5 (LOWEST PAYLOAD SERVICE STATION). NOTE RING ATTACHMENT FOR PERSONNEL SAFETY HARNESS IN LEFT FOREGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  2. Design curves for circular and annular duct silencers

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Ramakrishnan, R.

    1989-01-01

    Conventional models of sound propagation between porous walls (Scott, 1946) are adapted in order to calculate design curves for the lined circular and annular-duct silencers used in HVAC systems. The derivation of the governing equations is outlined, and results for two typical cases are presented graphically. Good agreement with published experimental data is demonstrated.

  3. 27. DUCT LINES AND HOLES TO BE LEFT IN TRANSFORMER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. DUCT LINES AND HOLES TO BE LEFT IN TRANSFORMER ROOM AND GALLERY, MENTONE, MAR. 13, 1904. R.S. MASSON, CONSULTING ELECTRICAL ENGINEER, SAN FRANCISCO AND LOS ANGELES. SCE drawing no. 52319. - Santa Ana River Hydroelectric System, SAR-3 Powerhouse, San Bernardino National Forest, Redlands, San Bernardino County, CA

  4. The Detection of Radiated Modes from Ducted Fan Engines

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Nark, Douglas M.; Thomas, Russell H.

    2001-01-01

    The bypass duct of an aircraft engine is a low-pass filter allowing some spinning modes to radiate outside the duct. The knowledge of the radiated modes can help in noise reduction, as well as the diagnosis of noise generation mechanisms inside the duct. We propose a nonintrusive technique using a circular microphone array outside the engine measuring the complex noise spectrum on an arc of a circle. The array is placed at various axial distances from the inlet or the exhaust of the engine. Using a model of noise radiation from the duct, an overdetermined system of linear equations is constructed for the complex amplitudes of the radial modes for a fixed circumferential mode. This system of linear equations is generally singular, indicating that the problem is illposed. Tikhonov regularization is employed to solve this system of equations for the unknown amplitudes of the radiated modes. An application of our mode detection technique using measured acoustic data from a circular microphone array is presented. We show that this technique can reliably detect radiated modes with the possible exception of modes very close to cut-off.

  5. Optimizing the Treatment of Acute Duct-Destructive Pancreatitis

    ERIC Educational Resources Information Center

    Zhakiev, Bazylbek S.; Karsakbayev, Uteugali G.; Kelimberdiev, Mersaid S.; ?uhamedgalieva, Bodagoz M.; K?nonenko, Aleksander F.

    2016-01-01

    The search for new methods for treating duct-destructive pancreatitis is a relevant problem. Endogenous intoxication and oxidative stress that accompany acute pancreatitis often progress even after surgery, which forces one to search for additional possibilities of preventing these severe consequences. This research studied the effect of small…

  6. Common bile duct obstruction caused by the hydatid daughter cysts.

    PubMed

    Busić, Zeljko; Amić, Enio; Servis, Draien; Predrijevac, Mladen; Stipancić, Igor; Busić, Dubravka

    2004-06-01

    Echinococcosis is a human parasitary disease. In 2002, 29 new cases of liver echinococcosis were recorded in Croatia. Liver is the most common site of hydatid cysts. Nine patients with echinoccocal liver disease were operated in our department in 2002. Here we present a case where a patient with verified hydatid cyst in the left liver lobe developed high fever, jaundice, nausea, vomiting and pain in the upper abdomen. The symptoms were initially ascribed to the acute cholangitis. After unsuccessful antibiotic treatment, computerized tomography and endoscopic retrograde cholangiopancreatography (ERCP) were performed, demonstrating daughter cysts in the common bile duct. During ERCP, papilotomy was made and daughter cysts were extracted. Hydatid cyst was surgically removed, and a communication between the cyst and left hepatic duct was noted during surgery. Pericystectomy, choledochotomy, removal of remaining daughter cysts from the common bile duct, and sutures of left hepatic duct were performed. The patient recovered fully after the surgery. One of the possible complications of the liver hydatid cysts is the communication between cyst and the biliary tree. Such communications are usually asymptomatic, but symptoms can also mimic acute cholangitis and jaundice, which may lead to the misdiagnosis of the patient's condition.

  7. Annular linear induction pump with an externally supported duct

    DOEpatents

    Craig, Edwin R.; Semken, Robert S.

    1979-01-01

    Several embodiments of an annular linear induction pump for pumping liquid metals are disclosed having the features of generally one pass flow of the liquid metal through the pump and an increased efficiency resulting from the use of thin duct walls to enclose the stator. The stator components of this pump are removable for repair and replacement.

  8. Obstructive jaundice due to radiation-induced hepatic duct stricture

    SciTech Connect

    Chandrasekhara, K.L.; Iyer, S.K.

    1984-10-01

    A case of obstructive jaundice due to radiation-induced hepatic duct stricture is reported. The patient received postoperative radiation for left adrenal carcinoma, seven years prior to this admission. The sequelae of hepatobiliary radiation and their management are discussed briefly.

  9. 16. FOREGROUND (LEFT TO RIGHT) EXHAUST AND INTAKE DUCTS. SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. FOREGROUND (LEFT TO RIGHT) EXHAUST AND INTAKE DUCTS. SOUTH SIDE AND WEST FRONT OF LAUNCH CONTROL SUPPORT BUILDING IN BACKGROUND. VIEW TO NORTH. - Minuteman III ICBM Launch Control Facility November-1, 1.5 miles North of New Raymer & State Highway 14, New Raymer, Weld County, CO

  10. Experimental study on the particles deposition in the sampling duct

    SciTech Connect

    Vendel, J.; Charuau, J.

    1995-02-01

    A high standard of protection against the harmful effects of radioactive aerosol dissemination requires a measurement, as representative as possible, of their concentration. This measurement depends on the techniques used for aerosol sampling and transfer to the detector, as well as on the location of the latter with respect to the potential sources. The aeraulic design of the apparatus is also an important factor. Once collected the aerosol particles often have to travel through a variably shaped duct to the measurement apparatus. This transport is responsible for losses due to the particles deposition on the walls, leading to a distortion on the concentration measurements and a change in the particle size distribution. To estimate and minimize measurement errors it is important to determine the optimal transport conditions when designing a duct; its diameter and material, the radius of curvature of the bends and the flow conditions must be defined in particular. This paper presents an experimental study in order to determine, for each deposition mechanism, the retained fraction, or the deposition velocity for different flow regimes. This study has pointed out that it exists a favourable flow regime for the particle transport through the sampling ducts (2 500 < Re < 5 000). It has been established, for any particle diameters, equations to predict the aerosol penetration in smooth-walled cylindrical metal ducts.

  11. 4. An interior view of remaining duct system and grain ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. An interior view of remaining duct system and grain separating equipment is situated within the 'Landmark' (1940) in the section above the silo portion of the structure. - Quaker Oats Cereal Factory, Southeast corner of Broadway & Mill Streets, Akron, Summit County, OH

  12. Thyroglossal Duct Papillary Thyroid Carcinoma and Synchronous Lingual Thyroid Atypia

    PubMed Central

    Yoo, Timothy; Kim, Yohanan; Simental, Alfred; Inman, Jared C.

    2016-01-01

    Thyroglossal duct and lingual thyroid ectopic lesions are exceedingly rare synchronous findings. Papillary thyroid carcinoma of these ectopic thyroid sites is well understood but still a rare finding. This case points to some management nuances in regard to ectopic thyroid screening with imaging and also shows the effectiveness of minimally invasive transoral robotic surgery for lingual thyroid. PMID:27119036

  13. Sertraline-Associated Cholestasis and Ductopenia Consistent with Vanishing Bile Duct Syndrome.

    PubMed

    Conrad, Máire A; Cui, Jiawei; Lin, Henry C

    2016-02-01

    An adolescent with depression treated with sertraline developed cholestasis and bile duct paucity, which resolved with medication discontinuation. Vanishing bile duct syndrome is an acquired destruction of interlobular bile ducts. This type of drug-induced liver injury has been associated with other medications and requires practitioners' awareness of potential hepatotoxicity.

  14. Cellular mechanisms of Müllerian duct formation in the mouse.

    PubMed

    Orvis, Grant D; Behringer, Richard R

    2007-06-15

    Regardless of their sex chromosome karyotype, amniotes develop two pairs of genital ducts, the Wolffian and Müllerian ducts. As the Müllerian duct forms, its growing tip is intimately associated with the Wolffian duct as it elongates to the urogenital sinus. Previous studies have shown that the presence of the Wolffian duct is required for the development and maintenance of the Müllerian duct. The Müllerian duct is known to form by invagination of the coelomic epithelium, but the mechanism for its elongation to the urogenital sinus remains to be defined. Using genetic fate mapping, we demonstrate that the Wolffian duct does not contribute cells to the Müllerian duct. Experimental embryological manipulations and molecular studies show that precursor cells at the caudal tip of the Müllerian duct proliferate to deposit a cord of cells along the length of the urogenital ridge. Furthermore, immunohistochemical analysis reveals that the cells of the developing Müllerian duct are mesoepithelial when deposited, and subsequently differentiate into an epithelial tube and eventually the female reproductive tract. Our studies define cellular and molecular mechanisms for Müllerian duct formation.

  15. Cooling air recycling for gas turbine transition duct end frame and related method

    DOEpatents

    Cromer, Robert Harold; Bechtel, William Theodore; Sutcu, Maz

    2002-01-01

    A method of cooling a transition duct end frame in a gas turbine includes the steps of a) directing cooling air into the end frame from a region external of the transition duct and the impingement cooling sleeve; and b) redirecting the cooling air from the end frame into the annulus between the transition duct and the impingement cooling sleeve.

  16. Extracorporeal abdominal massage may help prevent recurrent bile duct stones after endoscopic sphincterotomy

    PubMed Central

    Uchida, Naohito; Hamaya, Sae; Tatsuta, Miwa; Nakatsu, Toshiaki

    2016-01-01

    Background and study aims: Endoscopic sphincterotomy (EST) is effective, but recurrent bile duct stones are a common late complication. Because there are still no effective therapies for preventing this complication, some patients have experienced bile duct stone recurrence many times. We describe herein a method of abdominal massage to treat patients with prior cholecystectomy who have experienced recurrence of bile duct stones. PMID:27540575

  17. Percutaneous transhepatic hybrid biliary endoprostheses using both plastic and metallic stents for palliative treatment of malignant common bile duct obstruction.

    PubMed

    Fujita, T; Tanabe, M; Takahashi, S; Iida, E; Matsunaga, N

    2013-11-01

    To evaluate clinical safety and efficacy of percutaneous transhepatic hybrid biliary prostheses for palliative treatment in patients with common bile duct obstruction caused by advanced malignancies. A total of 13 consecutive patients was treated with percutaneous transhepatic biliary endoprostheses concurrently using both plastic and metallic stents. Serum total bilirubin levels before and after stent placement were evaluated. The technical success rate, the period with no obstructive jaundice, patient survival and complications were also assessed. Median bilirubin levels decreased from 3.8 mg/dL before to 1.2 mg/dL after stent placement, and this difference was statistically significant. The median no-jaundice period after bile duct stent placement was 6.0 months (range: 2-11 months), and overall survival time was 7.0 months. Of the 13 patients, nine did not have recurrent jaundice by the time of death, whereas four (31%) had recurrent jaundice. A second intervention was performed in these four patients. A new plastic stent was placed and jaundice did not recur up to the time of death. No serious complications such as cholangitis, pancreatitis or bile duct perforation developed. Percutaneous transhepatic hybrid biliary endoprostheses using both plastic and metallic stents can be useful as non-invasive palliative treatment to relieve jaundice in patients with malignant obstructive jaundice.

  18. A Novel Model of Severe Gallstone Pancreatitis: Murine Pancreatic Duct Ligation Results in Systemic Inflammation and Substantial Mortality

    PubMed Central

    Samuel, Isaac; Yuan, Zuobiao; Meyerholz, David K.; Twait, Erik; Williard, Deborah E.; Kempuraj, Duraisamy

    2010-01-01

    Background Suitable experimental models of gallstone pancreatitis with systemic inflammation and mortality are limited. We developed a novel murine model of duct-ligation-induced acute pancreatitis associated with multiorgan dysfunction and severe mortality. Methods Laparotomy was done on C57/BL6 mice followed by pancreatic duct (PD) ligation, bile duct (BD) ligation without PD ligation, or sham operation. Results Only mice with PD ligation developed acute pancreatitis and had 100% mortality. Pulmonary compliance was significantly reduced after PD ligation but not BD ligation. Bronchoalveolar lavage fluid neutrophil count and interleukin-1β concentration, and the plasma creatinine level, were significantly elevated with PD ligation but not BD ligation. Pancreatic nuclear factor κB (p65) and activator protein 1 (c-Jun) were activated within 1 h of PD ligation. Conclusion PD-ligation-induced acute pancreatitis in mice is associated with systemic inflammation, acute lung injury, multiorgan dysfunction and death. The development of this novel model is an exciting and notable advance in the field. PMID:20975317

  19. Modal Analysis in Lined Wedge-Shaped Ducts

    NASA Astrophysics Data System (ADS)

    Mechel, F. P.

    1998-10-01

    It has been suggested to describe the sound field in a wedge-shaped duct in a cylindrical co-ordinate system in which the boundaries of the wedge lie in a co-ordinate surface. This suggestion was developed in a companion paper [1]. The wave equation can be separated only if the boundaries are ideally reflecting (rigid or soft). Two solutions were proposed in reference [1] for absorbing boundaries. In the first solution the sound field is composed of “ideal modes” (modes in a wedge with ideally reflecting boundaries); the boundary condition at the absorbing boundary then leads to a system of equations for the mode amplitudes. The problem with this method lies in the fact that there is no radial orthogonality of the ideal modes so that the precision of the field synthesis by ideal modes is doubtful. In the second method in reference [1] one defines “fictitious modes” which satisfy the boundary conditions at the flanks exactly and which are based on hypergeometric functions as radial functions, but which produce a “rest” in the wave equation. It was described how this rest can be minimized; this procedure leads to slow numerical integrations. In the present paper, the wedge is subdivided into duct sections with parallel walls (the boundary is stepped); the fields in the sections are composed of duct modes (modes in a straight lined duct); the mode amplitudes are determined from the boundary conditions at the section limits. The advantages of the present method are (analytically) the duct modes are orthogonal across the sections, so the mode amplitudes can be determined with the usual precision of a modal analysis, and (numerically) no numerical integrations are needed.

  20. Modified External Dacryocystorhinostomy in Primary Acquired Nasolacrimal Duct Obstruction

    PubMed Central

    Sharma, Ashok K.; Sharma, Rajni

    2015-01-01

    Background Epiphora secondary to acquired nasolacrimal duct obstruction is a common ophthalmic problem in adults requiring surgical management. External dacryocystorhinostomy (DCR) is a reliable but difficult surgical technique for the treatment of nasolacrimal duct obstruction. Purpose To evaluate the success rate and complications of modified external DCR in patients with primary acquired nasolacrimal duct obstruction. Materials and Methods This hospital based prospective interventional study included 56 patients with primary acquired nasolacrimal duct obstruction. Diagnosis of nasolacrimal duct obstruction was made through irrigation of the nasolacrimal drainage system. All patients were operated by modified technique of external DCR with anastomosis of the anterior lacrimal and nasal mucosal flaps only, whereas posterior mucosal flaps were excised. Patients were followed up for a period of 6 months. During the follow up, success rate and complications if any were recorded. Success was defined objectively by a patent lacrimal passage on irrigation and subjectively by the absence of watering or discharge. Results The mean age of the study population was 39.23 ± 10.66 years, and 78.6% of patients were females (male to female ratio 1:3.7). The average operation time was 36.48 ± 4.72 minutes. Objective and subjective success rates were 92.9% and 89.3%, respectively after a follow up period of 6 months. Intraoperatively, haemorrhage occurred in 3 patients (5.3%) and laceration of the nasal mucosa in 4 patients (7.1%). Postoperative complications included significant lid swelling and periorbital ecchymosis in 3 patients (5.3%), epistaxis in 2 patients (3.6%) and hypertrophic scar in 2 patients (3.6%). Conclusion These results suggest that modified external DCR with anterior flaps anastomosis only is a simple, safe, less time consuming surgical technique that is easy to perform, and the outcome is comparable to conventional DCR. PMID:26557549

  1. Early T Stage Salivary Duct Carcinoma: Outcomes and Implications for Patient Counseling

    PubMed Central

    Schmitt, Nicole C.; Sharma, Arun; Gilbert, Mark R.; Kim, Seungwon

    2016-01-01

    Salivary duct carcinoma (SDC) is a rare salivary malignancy that often presents at advanced stage. Outcomes of low T stage patients with SDC have not been previously examined in detail. We queried our institution’s cancer database and identified 28 patients with SDC in situ or T1/T2 SDC. A retrospective chart review was performed, followed by comparison of clinicopathologic features with N stage, disease-free survival, and overall survival. Patients tended to be male, in their sixties, with a high incidence of regional metastases, as in prior reports. Five-year disease-free and overall survival were 49%. Median disease-free survival was 3.24 years, and overall survival was 4.65 years. Parotid location, vascular invasion, facial nerve sacrifice, and extracapsular extension were associated with worse survival. This study provides practical information for counseling of patients who undergo surgery for a parotid mass and are found to have this aggressive malignancy. PMID:26307577

  2. Early T Stage Salivary Duct Carcinoma: Outcomes and Implications for Patient Counseling.

    PubMed

    Schmitt, Nicole C; Sharma, Arun; Gilbert, Mark R; Kim, Seungwon

    2015-11-01

    Salivary duct carcinoma (SDC) is a rare salivary malignancy that often presents at advanced stage. Outcomes of low T stage patients with SDC have not been previously examined in detail. We queried our institution's cancer database and identified 28 patients with SDC in situ or T1/T2 SDC. A retrospective chart review was performed, followed by comparison of clinicopathologic features with N stage, disease-free survival, and overall survival. Patients tended to be male, in their sixties, with a high incidence of regional metastases, as in prior reports. Five-year disease-free and overall survival were 49%. Median disease-free survival was 3.24 years, and overall survival was 4.65 years. Parotid location, vascular invasion, facial nerve sacrifice, and extracapsular extension were associated with worse survival. This study provides practical information for counseling of patients who undergo surgery for a parotid mass and are found to have this aggressive malignancy. PMID:26307577

  3. High prevalence of proposed Müllerian duct remnant cysts on the spermatic duct in wild Eurasian otters (Lutra lutra) from Sweden.

    PubMed

    Roos, Anna M; Ågren, Erik O

    2013-01-01

    The spermatic ducts (vasa deferentia) of 235 otters (Lutra lutra) found dead between 1999 and 2012 in Sweden were examined for presence of paraductular cysts. Single or multiple elongated uni- or bilateral cysts parallel to the spermatic duct were noted in 72% of the examined males. The cysts were adjacent to, but did not communicate with the lumen of the spermatic duct, and were usually located within a few centimeters of the testis and epididymis. The cysts are proposed to be congenital Müllerian duct remnants. Other morphologic abnormalities in the reproductive organs were not noted within this study. Possible causes of the incomplete regression of the embryonic female gonadal duct are exposure to environmental contaminants such as elevated concentrations of estrogen-like compounds (endocrine disrupting chemicals), inbreeding, or a naturally occurring anatomic defect. No obvious geographical pattern was observed for otters with or without cysts. This is the first study and description of cysts on the spermatic duct in otters.

  4. Experiments measuring particle deposition from fully developed turbulent flow in ventilation ducts

    SciTech Connect

    Sippola, Mark R.; Nazaroff, William W.

    2003-08-01

    Particle deposition in ventilation ducts influences particle exposures of building occupants and may lead to a variety of indoor air quality concerns. Experiments have been performed in a laboratory to study the effects of particle size and air speed on deposition rates of particles from turbulent air flows in galvanized steel and internally insulated ducts with hydraulic diameters of 15.2 cm. The duct systems were constructed of materials typically found in commercial heating, ventilating and air conditioning (HVAC) systems. In the steel duct system, experiments with nominal particle sizes of 1, 3, 5, 9 and 16 {micro}m were conducted at each of three nominal air speeds: 2.2, 5.3 and 9.0 m/s. In the insulated duct system, deposition rates of particles with nominal sizes of 1, 3, 5, 8 and 13 {micro}m were measured at nominal air speeds of 2.2, 5.3 and 8.8 m/s. Fluorescent techniques were used to directly measure the deposition velocities of monodisperse fluorescent particles to duct surfaces (floor, wall and ceiling) at two straight duct sections where the turbulent flow profile was fully developed. In steel ducts, deposition rates were higher to the duct floor than to the wall, which were, in turn, greater than to the ceiling. In insulated ducts, deposition was nearly the same to the duct floor, wall and ceiling for a given particle size and air speed. Deposition to duct walls and ceilings was greatly enhanced in insulated ducts compared to steel ducts. Deposition velocities to each of the three duct surface orientations in both systems were found to increase with increasing particle size or air velocity over the ranges studied. Deposition rates measured in the current experiments were in general agreement with the limited observations of similar systems by previous researchers.

  5. Lhx1 is required in Müllerian duct epithelium for uterine development.

    PubMed

    Huang, Cheng-Chiu; Orvis, Grant D; Kwan, Kin Ming; Behringer, Richard R

    2014-05-15

    The female reproductive tract organs of mammals, including the oviducts, uterus, cervix and upper vagina, are derived from the Müllerian ducts, a pair of epithelial tubes that form within the mesonephroi. The Müllerian ducts form in a rostral to caudal manner, guided by and dependent on the Wolffian ducts that have already formed. Experimental embryological studies indicate that caudal elongation of the Müllerian duct towards the urogenital sinus occurs in part by proliferation at the ductal tip. The molecular mechanisms that regulate the elongation of the Müllerian duct are currently unclear. Lhx1 encodes a LIM-homeodomain transcription factor that is essential for male and female reproductive tract development. Lhx1 is expressed in both the Wolffian and Müllerian ducts. Wolffian duct-specific knockout of Lhx1 results in degeneration of the Wolffian duct and consequently the non-cell-autonomous loss of the Müllerian duct. To determine the role of Lhx1 specifically in the Müllerian duct epithelium, we performed a Müllerian duct-specific knockout study using Wnt7a-Cre mice. Loss of Lhx1 in the Müllerian duct epithelium led to a block in Müllerian duct elongation and uterine hypoplasia characterized by loss of the entire endometrium (luminal and glandular epithelium and stroma) and inner circular but not the outer longitudinal muscle layer. Time-lapse imaging and molecular analyses indicate that Lhx1 acts cell autonomously to maintain ductal progenitor cells for Müllerian duct elongation. These studies identify LHX1 as the first transcription factor that is essential in the Müllerian duct epithelial progenitor cells for female reproductive tract development. Furthermore, these genetic studies demonstrate the requirement of epithelial-mesenchymal interactions for uterine tissue compartment differentiation.

  6. Lhx1 is required in Müllerian duct epithelium for uterine development

    PubMed Central

    Huang, Cheng-Chiu; Orvis, Grant D.; Kwan, Kin Ming; Behringer, Richard R.

    2014-01-01

    The female reproductive tract organs of mammals, including the oviducts, uterus, cervix and upper vagina, are derived from the Müllerian ducts, a pair of epithelial tubes that form within the mesonephroi. The Müllerian ducts form in a rostral to caudal manner, guided by and dependent on the Wolffian ducts that have already formed. Experimental embryological studies indicate that caudal elongation of the Müllerian duct towards the urogenital sinus occurs in part by proliferation at the ductal tip. The molecular mechanisms that regulate the elongation of the Müllerian duct are currently unclear. Lhx1 encodes a LIM-homeodomain transcription factor that is essential for male and female reproductive tract development. Lhx1 is expressed in both the Wolffian and Müllerian ducts. Wolffian duct-specific knockout of Lhx1 results in degeneration of the Wolffian duct and consequently the non cell-autonomous loss of the Müllerian duct. To determine the role of Lhx1 specifically in the Müllerian duct epithelium, we performed a Müllerian duct-specific knockout study using Wnt7a-Cre mice. Loss of Lhx1 in the Müllerian duct epithelium led to a block in Müllerian duct elongation and uterine hypoplasia characterized by loss of the entire endometrium (luminal and glandular epithelium and stroma) and inner circular but not the outer longitudinal muscle layer. Time-lapse imaging and molecular analyses indicate that Lhx1 acts cell autonomously to maintain ductal progenitor cells for Müllerian duct elongation. These studies identify LHX1 as the first transcription factor that is essential in the Müllerian duct epithelial progenitor cells for female reproductive tract development. Furthermore, these genetic studies demonstrate the requirement of epithelial-mesenchymal interactions for uterine tissue compartment differentiation. PMID:24560999

  7. Temporary Trans-jejunal Hepatic Duct Stenting in Roux-en-y Hepaticojejunostomy for Reconstruction of Iatrogenic Bile Duct Injuries

    PubMed Central

    Sadegh Fazeli, Mohammad; Kazemeini, Ali Reza; Jafarian, Ali; Bashashati, Mohammad; Keramati, Mohammad Reza

    2016-01-01

    Background Bile Duct Injuries (BDI) during cholecystectomy are now being recognized as major health problems. Objectives Herein, we present our experience with handling major BDIs and report long-term outcome of hepaticojejunostomies followed by trans-jejunal hepatic duct stenting performed to reconstruct extra-hepatic biliary tracts. Materials and Methods In this case series, we prospectively collected data of 22 patients, who underwent first time biliary reconstruction through Roux-en-y hepaticojejunostomy followed by hepatic duct stenting using a trans-jejunal bifurcated 6F tube drain. The long-term outcome was assessed and defined as excellent (asymptomatic, normal liver enzymes and bilirubin levels), good (asymptomatic, mild abnormality in liver enzyme and bilirubin levels), poor (symptomatic, abnormal liver enzymes and bilirubin level) and failure (requiring reoperation). Results A total of 22 patients including four males (18.1%) and 18 females (81.8%) were evaluated. The mean age was 42.71 (range: 23 - 74) years. Twelve patients had undergone open cholecystectomy (54.5%) and the rest had a history of laparoscopic cholecystectomy. The mean interval between the primary operation and reconstruction was 92.71 days. The mean follow-up period after biliary reconstruction was 42.33 (range: 1 - 96) months. No instance of anastomotic leakage or stenosis, biliary sepsis, thromboembolic event, or respiratory infection was noted in the long-term follow-up. The outcome was excellent in all patients. No case with poor or failure of result was noticed. Conclusions Although a devastating complication iatrogenic major bile duct injuries can be corrected surgically with a high rate of success. Temporary trans-jejunal stenting of the hepatic ducts can help in maintaining the integrity of anastomosis without stenosis or biliary sepsis. PMID:27626003

  8. Papillary Carcinoma Within a Thyroglossal Duct Cyst in a 17-Year-Old Child.

    PubMed

    Cheon, Nam Ju; Lee, Young Man; Lee, Jun Ho; Han, Jong Kyu; Lee, Ji Hye

    2016-05-01

    Thyroglossal duct cyst is a frequent event; however, papillary carcinoma within a thyroglossal duct cyst is rare, particularly in children. A 17-year-old girl presented with an asymptomatic mid-submental mass for the last 2 months. The diagnosis of thyroglossal duct cyst was made based on physical examination and computed tomography finding. After performance of Sistrunk procedure, an incidental papillary carcinoma within the thyroglossal duct cyst was observed on pathology. We reviewed the pediatric cases of thyroglossal duct carcinoma, and then decided not to perform a concurrent thyroidectomy. We will continue close follow-up for future thyroid involvement. PMID:27054418

  9. Design of power-plant installations pressure-loss characteristics of duct components

    NASA Technical Reports Server (NTRS)

    Henry, John R

    1944-01-01

    A correlation of what are believed to be the most reliable data available on duct components of aircraft power-plant installations is presented. The information is given in a convenient form and is offered as an aid in designing duct systems and, subject to certain qualifications, as a guide in estimating their performance. The design and performance data include those for straight ducts; simple bends of square, circular, and elliptical cross sections; compound bends; diverging and converging bends; vaned bends; diffusers; branch ducts; internal inlets; and an angular placement of heat exchangers. Examples are included to illustrate methods of applying these data in analyzing duct systems. (author)

  10. Preneoplastic conditions underlying bile duct cancer

    PubMed Central

    Sibulesky, Lena; Nguyen, Justin; Patel, Tushar

    2012-01-01

    Background Malignancies arising from the biliary tract can arise from the epithelial lining of the biliary tract and surrounding tissues. Conditions that predispose to malignancy as well as preneoplastic changes in biliary tract epithelia have been identified. In this overview, we discuss preneoplastic conditions of the biliary tract and emphasize their clinical relevance. Results Chronic biliary tract inflammation predisposes to cancer in the biliary tract. Biliary tract carcinogenesis involves a multistep process as a consequence of chronic biliary epithelial injury or inflammation. Reminiscent of other gastrointestinal epithelial malignancies such as gastric, colon, and pancreatic cancer, biliary tract cancers may evolve via a multistep progression from epithelial hyperplasia and dysplasia to malignant transformation. The potential role of initiating cells is also becoming recognized. Conclusions In spite of improved risk factor recognition, and advances in diagnostic tools, the early diagnosis of pre-malignant or malignant biliary tract conditions is extremely challenging, and there is a paucity of evidence on which to base their management. As a result, the role of pre-emptive surgery remains largely undefined. PMID:22391777

  11. Configuration Effects on Acoustic Performance of a Duct Liner

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Brown, Martha C.; Jones, Michael G.; Nark, Douglas; Howerton, Brian M.

    2008-01-01

    Continued success in aircraft engine noise reduction necessitates ever more complete understanding of the effect that flow path geometry has on sound propagation in the engine. The Curved Duct Test Rig (CDTR) has been developed at NASA Langley Research Center to investigate sound propagation through a duct of comparable size (approximately the gap of GE90) and physical characteristics to the aft bypass duct of typical aircraft engines. The liner test section is designed to mimic the outer/inner walls of an engine exhaust bypass duct that has been unrolled circumferentially. Experiments to investigate the effect of curvature along the flow path on the acoustic performance of a test liner are performed in the CDTR and reported in this paper. Flow paths investigated include both straight and curved with offsets from the inlet to the discharge plane of and 1 duct width, respectively. The test liners are installed on the side walls of the liner test section. The liner samples are perforate over honeycomb core, which design is typical of liners installed in aircraft nacelles. In addition to fully treated side walls, combinations of treated and acoustically rigid walls are investigated. While curvature in the hard wall duct is found not to reduce the incident sound significantly, it does cause mode scattering. It is found that asymmetry of liner treatment causes scattering of the incident mode into less attenuated modes, which degrades the overall liner attenuation. It is also found that symmetry of liner treatment enhances liner performance by eliminating scattering into less attenuated modes. Comparisons of measured liner attenuation with numerical results predicted by an analytic model based on the parabolic approximation (CDUCT-LaRC) have also been made and are reported in this paper. The effect of curvature in the rigid wall configuration estimated by CDUCT-LaRC is similar to the observed results, and the mode scattering seen in the measurements also occurs in the

  12. Retroperitoneal Biloma Secondary to Operative Common Bile Duct Injury

    PubMed Central

    Čólović, Radoje; Perišić-Savić, Mirjana

    1991-01-01

    Encapsulated collections of bile (“biloma”) may be a sequela of liver trauma, operative injury or disease. Such collections may be intrahepatic or extrahepatic and usually in the supramesocolic compartment of the abdomen. This is a report of a retroperitoneal biloma, an entity that has been reported only twice to date but this is the first secondary to an operative common bile duct lesion. Evacuation of the biloma and reconstruction of the associated biliary stricture were successfully carried out. The patient remains sympton free with normal clinical and laboratory data more than 14 months after surgery. Operative common bile duct (CBD) injury may be followed by a number of complications. To our knowledge retroperitoneal biloma secondary to a CBD lesion has not been previously reported. PMID:2043516

  13. Intrahepatic Duct Stones Harboring Ascariasis Ova: A Case Report.

    PubMed

    Lee, Chen-Fang; Lee, Wei-Chen; Wu, Ren-Chin; Chen, Tse-Ching

    2016-03-01

    Ascariasis lumbricoides is one of the most common helminthic infestations in humans. Despite the fact that the prevalence of ascariasis in developed countries has been decreasing, biliary ascariasis can cause serious complications, such as acute cholangitis, pancreatitis, and liver abscess. Here we presented a rare ascariasis-related complication-hepatolithiasis.A 60-year-old female patient had symptoms of recurrent cholangitis. Abdominal computed tomography scan revealed left intrahepatic duct stones with left liver lobe atrophy. Endoscopic retrograde cholangiopancreatography was performed, but the stones could not be removed due to left main intrahepatic duct stenosis. The patient was treated with left hemi-hepatectomy. Unexpectedly, Ascaris ova were found on the histopathological examination. She received antihelminthic therapy orally and was on regular follow-up without any complications.Our study indicates that clinicians should be aware of biliary ascariasis in patients with hepatolithiasis, though not living in endemic areas. PMID:27015193

  14. Marginal turbulent magnetohydrodynamic flow in a square duct

    NASA Astrophysics Data System (ADS)

    Shatrov, Victor; Gerbeth, Gunter

    2010-08-01

    Direct numerical simulations using a high-order finite-difference method were performed of the turbulent flow in a straight square duct in a transverse magnetic field. Without magnetic field the turbulence can be maintained for values of the bulk Reynolds number above approximately Re=1077 [M. Uhlmann et al., "Marginally turbulent flow in a square duct," J. Fluid Mech. 588, 153 (2007)]. In the magnetohydrodynamic case this minimal value of the bulk Reynolds number increases with the Hartmann number. The flow is laminar at Re=3000 when the Hartmann number is larger than Ha=12.5 and the flow is turbulent for Ha≦12.0. The secondary mean flow structure at Re=3000 consists of eight vortices located mainly at the Hartmann walls.

  15. Sound power flux measurements in strongly exited ducts with flow

    NASA Astrophysics Data System (ADS)

    Holland, Keith R.; Davies, Peter O. A. L.; van der Walt, Danie C.

    2002-12-01

    This contribution describes new robust procedures for the measurement of sound power flux at appropriate axial positions along a duct with flow, using pairs of flush wall mounted microphones, or pressure transducers. The technology includes the application of selective averaging, order tracking, and optimized sampling rate methods to identify the small fraction of the total fluctuating wave energy that is being propagated along the flow path in a reverberent, or highly reactive duct system. Such measurements can also be used to quantify the local acoustic characteristics that govern the generation, transfer, and propagation of wave energy in the system. Illustrative examples include the determination of the acoustic characteristics of individual silencing elements installed in IC engine intakes and exhausts both on the flow bench and during controlled acceleration or run down on a test bed, where the wave component spectral levels approached 170 dB.

  16. [Experience in thyroglossal duct pathology: clinical case series].

    PubMed

    Cieri, Patricio; Udaquiola, Julia E; Calello, Santiago E; Libero, Daniel H

    2016-10-01

    The thyroglossal duct cyst pathology represents the second cause of bening cervical anomalies in childhood. Diagnosis is mainly clinical. Sistrunk (1920) proposed a surgical technique that is still considered the gold standard for definitive treatment of this condition. A retrospective study was made including patients who underwent surgery for thyroglossal duct cyst pathology in our department between June 2008 and August 2015. In this period, we performed 54 procedures in 45 patients (39 primary cases). Median age was 4.7 years; 14/39 patients (31.1%) had pre-operative infection. All patients were studied with neck ultrasound. A Sistrunk's procedure was performed in all cases. The global recurrence rate was 17.8% (8/45).

  17. Primary sclerosing cholangitis – The arteriosclerosis of the bile duct?

    PubMed Central

    Fickert, Peter; Moustafa, Tarek; Trauner, Michael

    2007-01-01

    Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease of unknown aetiology affecting the large bile ducts and characterized by periductal fibrosis and stricture formation, which ultimately result in biliary cirrhosis and liver failure. Arteriosclerosis involves the accumulation of altered lipids and lipoproteins in large arteries; this drives inflammation and fibrosis and ultimately leads to narrowing of the arteries and hypoperfusion of dependent organs and tissues. Knowledge of the causative factors is crucial to the understanding of disease mechanisms and the development of specific treatment. Based on pathogenetic similarities between PSC and arteriosclerosis, we hypothesize that PSC represents "arteriosclerosis of the bile duct" initiated by toxic biliary lipids. This hypothesis is based on common molecular, cellular, and morphological features providing the conceptual framework for a deeper understanding of their pathogenesis. This hypothesis should stimulate translational research to facilitate the search for novel treatment strategies for both diseases. PMID:17254334

  18. Laparoscopic common duct exploration in 90-bed rural hospital.

    PubMed

    Shively, Eugene H; Richardson, Malcolm; Romines, Robert; Englund, Graham; Watkins, James

    2010-06-01

    Laparoscopic common bile duct exploration (LCBDE) is an effective procedure when endoscopic retrograde cholangiopancreatography is not available. From January 2004 until December 2009, 1254 patients presented with biliary tract disease. Laparoscopic cholecystectomy was attempted in 1240 (98%) cases and completed in 1232 (98%) cases. Laparoscopic cholangiograms were performed in 627 (50%) cases. LCBDE was carried out in 33 (2.6%) cases. Of the 33 LCBDEs, 29 (2.3%) were via the cystic duct, four (0.32%) through a choledochotomy; eight (0.64%) of the total laparoscopic cholecystectomies were converted to open cholecystectomies. LCBDE can be done safely in small hospitals and is very useful when endoscopic retrograde cholangiopancreatography is not available.

  19. Nasal endoscopy in the management of congenital nasolacrimal duct obstruction

    PubMed Central

    Al-Faky, Yasser H.

    2013-01-01

    Probing is a reliable surgical intervention for the management of congenital nasolacrimal duct obstruction (CNLDO). However, it is a blind procedure that carries the risk of false passage formation. Moreover, its success rate is variable, with unexplained causes of failure. Recent literature suggests the use of nasal endoscopic-assisted probing to minimize nasal mucosal trauma, decreases the chance of creating a false passage and provides the optimum management option of different congenital variants of nasolacrimal duct obstruction. Nasal endoscopic-assisted probing has more or less consistent success rates varied between 85% and 98% compared with probing success rates, which vary between 55% and 95% despite having almost the same age range. PMID:24526852

  20. Common Hepatic Duct Mixed Adenoneuroendocrine Carcinoma Masquerading as Cholangiocarcinoma

    PubMed Central

    Priyanka Akhilesh, Sali; Kamal Sunder, Yadav; Chandralekha, Tampi; Samir, Parikh; Prasad Kashinath, Wagle

    2016-01-01

    Bile duct mixed adenoneuroendocrine carcinoma (MANEC) is a rare entity. It is defined as having mixed elements of both neuroendocrine tumors (NET) and an adenocarcinoma element, the lesser component forming at least 30% of the tumor. It is a subtype of neuroendocrine carcinoma (NEC) showing both gland-forming epithelial tumor cells and neuroendocrine cells. It is generally misdiagnosed as cholangiocarcinoma on imaging studies. The preoperative pathological workup from the endoscopic retrograde cholangiography brush cytology usually misses the NET/NEC component since it often lies deeper in the tumor. However, it is reported that it is the NEC component that defines the prognosis of the tumor; hence, it is vital to identify the NEC component. We present a rare case of common hepatic duct (CHD) MANEC that was preoperatively misdiagnosed as cholangiocarcinoma. PMID:27375908

  1. Wharton's duct repair after combined sialolithectomy: is ductoplasty necessary?

    PubMed

    Pagliuca, Giulio; Martellucci, Salvatore; de Vincentiis, Marco; Greco, Antonio; Fusconi, Massimo; De Virgilio, Armando; Rosato, Chiara; Gallo, Andrea

    2013-05-01

    The aim of this prospective study is to establish whether ductoplasty is necessary to repair the Wharton's duct after a combined endoscopic and external approach to remove large submandibular gland stones or if simple suturing of the oral floor mucosa after stent placement may be sufficient to achieve proper duct healing. Ten patients were enrolled. Ductoplasty was performed in 6 cases, whereas in 4 cases, only the mucosa of the oral floor was sutured. The stent was removed about 3 weeks after surgery. Sialoliths were completely removed in all cases. During follow-up, patient symptom evaluation, ultrasound, and physical examination showed no signs of recurrence or complications. In our limited experience, ductoplasty after the combined approach was not necessary. After stent placement, the mere suture of the oral mucosa overlying the damaged ductal wall allowed a correct recanalization of the ductal lumen as commonly observed after careful ductoplasty. PMID:23396595

  2. A model of the wall boundary layer for ducted propellers

    NASA Technical Reports Server (NTRS)

    Eversman, Walter; Moehring, Willi

    1987-01-01

    The objective of the present study is to include a representation of a wall boundary layer in an existing finite element model of the propeller in the wind tunnel environment. The major consideration is that the new formulation should introduce only modest alterations in the numerical model and should still be capable of producing economical predictions of the radiated acoustic field. This is accomplished by using a stepped approximation in which the velocity profile is piecewise constant in layers. In the limit of infinitesimally thin layers, the velocity profile of the stepped approximation coincides with that of the continuous profile. The approach described here could also be useful in modeling the boundary layer in other duct applications, particularly in the computation of the radiated acoustic field for sources contained in a duct.

  3. [Experience in thyroglossal duct pathology: clinical case series].

    PubMed

    Cieri, Patricio; Udaquiola, Julia E; Calello, Santiago E; Libero, Daniel H

    2016-10-01

    The thyroglossal duct cyst pathology represents the second cause of bening cervical anomalies in childhood. Diagnosis is mainly clinical. Sistrunk (1920) proposed a surgical technique that is still considered the gold standard for definitive treatment of this condition. A retrospective study was made including patients who underwent surgery for thyroglossal duct cyst pathology in our department between June 2008 and August 2015. In this period, we performed 54 procedures in 45 patients (39 primary cases). Median age was 4.7 years; 14/39 patients (31.1%) had pre-operative infection. All patients were studied with neck ultrasound. A Sistrunk's procedure was performed in all cases. The global recurrence rate was 17.8% (8/45). PMID:27606652

  4. Common Hepatic Duct Mixed Adenoneuroendocrine Carcinoma Masquerading as Cholangiocarcinoma.

    PubMed

    Priyanka Akhilesh, Sali; Kamal Sunder, Yadav; Chandralekha, Tampi; Samir, Parikh; Prasad Kashinath, Wagle

    2016-01-01

    Bile duct mixed adenoneuroendocrine carcinoma (MANEC) is a rare entity. It is defined as having mixed elements of both neuroendocrine tumors (NET) and an adenocarcinoma element, the lesser component forming at least 30% of the tumor. It is a subtype of neuroendocrine carcinoma (NEC) showing both gland-forming epithelial tumor cells and neuroendocrine cells. It is generally misdiagnosed as cholangiocarcinoma on imaging studies. The preoperative pathological workup from the endoscopic retrograde cholangiography brush cytology usually misses the NET/NEC component since it often lies deeper in the tumor. However, it is reported that it is the NEC component that defines the prognosis of the tumor; hence, it is vital to identify the NEC component. We present a rare case of common hepatic duct (CHD) MANEC that was preoperatively misdiagnosed as cholangiocarcinoma. PMID:27375908

  5. [Thyroglossal duct with papillary carcinoma. Report of a case].

    PubMed

    Cortés, R; Takahashi, T; Herrera, M F; Reyes, E; Reza, A; De la Garza, L

    1991-01-01

    We report the case of a 32-year old woman with an anterior cervical cystic mass originating in the thyroglossal duct. At surgical exploration, the mass was reacted, including the thyroglossal duct and the mid-portion of the hyoid bone (Sistrunk's procedure). The histopathologic study demonstrated a papillary carcinoma. Fine needle aspiration biopsies of both thyroid lobes were performed postoperatively without any histopathologic abnormalities. The patient was discharged without performing any other surgical procedure and without complications. Treatment with I131 and thyroid hormones was initiated, and at 11 months of follow-up, the patient is asymptomatic without any evidence of local or distant recurrence. The clinical and histopathological features are discussed, as well as the therapeutic options for this type of uncommon malignant neoplasm.

  6. In vivo multiphoton imaging of bile duct ligation

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Li, Feng-Chieh; Chen, Hsiao-Chin; Chang, Po-shou; Yang, Shu-Mei; Lee, Hsuan-Shu; Dong, Chen-Yuan

    2008-02-01

    Bile is the exocrine secretion of liver and synthesized by hepatocytes. It is drained into duodenum for the function of digestion or drained into gallbladder for of storage. Bile duct obstruction is a blockage in the tubes that carry bile to the gallbladder and small intestine. However, Bile duct ligation results in the changes of bile acids in serum, liver, urine, and feces1, 2. In this work, we demonstrate a novel technique to image this pathological condition by using a newly developed in vivo imaging system, which includes multiphoton microscopy and intravital hepatic imaging chamber. The images we acquired demonstrate the uptake, processing of 6-CFDA in hepatocytes and excretion of CF in the bile canaliculi. In addition to imaging, we can also measure kinetics of the green fluorescence intensity.

  7. Flow Through a Rectangular-to-Semiannular Diffusing Transition Duct

    NASA Technical Reports Server (NTRS)

    Foster, Jeff; Wendt, Bruce J.; Reichert, Bruce A.; Okiishi, Theodore H.

    1997-01-01

    Rectangular-to-semiannular diffusing transition ducts are critical inlet components on supersonic airplanes having bifucated engine inlets. This paper documents measured details of the flow through a rectangular-to-semiannular transition duct having an expansion area ratio of 1.53. Three-dimensional velocity vectors and total pressures at the exit plane of the diffuser are presented. Surface oil-flow visualization and surface static pressure data are shown. The tests were conducted with an inlet Mach number of 0.786 and a Reynolds number based on the inlet centerline velocity and exit diameter of 3.2 x 10(exp 6). The measured data are compared with previously published computational results. The ability of vortex generators to reduce circumferential total pressure distortion is demonstrated.

  8. Atmospheric ducts can transport sound in two directions

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2014-07-01

    When conditions are right, temperature gradients and fast jets of wind can help to establish atmospheric ducts—pathways in the atmosphere that promote the propagation of low-frequency acoustic waves (infrasound)—across long distances. Atmospheric ducts are part of the basis behind over-the-horizon radar, the source of some particularly clear mirages, and a channel through which sounds can travel relatively unperturbed across vast distances.

  9. [Endosonography in tumors of the pancreas and bile ducts].

    PubMed

    Nattermann, C; Dancygier, H

    1993-01-01

    The sensitivity of EUS in demonstrating pancreatic tumors lies above 90% and tumors smaller than 2 cm in diameter can be visualized. Therefore EUS can be applied e.g. in the early diagnosis of symptomatic endocrine tumors. However, it is not suited as a screening method for pancreatic carcinoma in asymptomatic patients. The EUS findings do not permit a clear differentiation between malignant and inflammatory (pseudo) tumors. The specificity for the demonstration of malignant tumors is 74%. Its main importance is in the locoregional staging of tumors. EUS is superior to all other imaging tools in determining tumor extension and infiltration into the portal or splenic vein. The pT-stage is determined correctly preoperatively in 90% and lymph node metastases (N1) in about 73% (sensitivity 80-90%/specificity 50%) of the cases. Malignant tumors of Vater's papilla (ampullary tumors) and of extrahepatic bile ducts can be demonstrated endosonographically in nearly all cases. However, tumors of the proximal bile ducts, especially of the right hepatic duct are difficult and sometimes impossible to visualize. The value of EUS in bile duct cancer is in local tumor staging. The pT-stage is determined correctly in 80-90%, the sensitivity and specificity for N1-stage is 80-90% and 30% respectively. Comparative studies with other methods are lacking at the present time. The value of EUS in gall bladder tumors is not yet determined. Stones in the gall bladder may hinder the visualization of the gall bladder wall. In one study the pT-stage for gall bladder carcinoma was determined correctly preoperatively in 76.9% and the N1-stage in 80.7% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Monograph on propagation of sound waves in curved ducts

    NASA Technical Reports Server (NTRS)

    Rostafinski, Wojciech

    1991-01-01

    After reviewing and evaluating the existing material on sound propagation in curved ducts without flow, it seems strange that, except for Lord Rayleigh in 1878, no book on acoustics has treated the case of wave motion in bends. This monograph reviews the available analytical and experimental material, nearly 30 papers published on this subject so far, and concisely summarizes what has been learned about the motion of sound in hard-wall and acoustically lined cylindrical bends.

  11. Aldosterone Activates NF-κB in the Collecting Duct

    PubMed Central

    Leroy, Valérie; De Seigneux, Sophie; Agassiz, Victor; Hasler, Udo; Rafestin-Oblin, Marie-Edith; Vinciguerra, Manlio; Martin, Pierre-Yves; Féraille, Eric

    2009-01-01

    Besides its classical effects on salt homeostasis in renal epithelial cells, aldosterone promotes inflammation and fibrosis and modulates cell proliferation. The proinflammatory transcription factor NF-κB has been implicated in cell proliferation, apoptosis, and regulation of transepithelial sodium transport. The effect of aldosterone on the NF-κB pathway in principal cells of the cortical collecting duct, a major physiologic target of aldosterone, is unknown. Here, in both cultured cells and freshly isolated rat cortical collecting duct, aldosterone activated the canonical NF-κB signaling pathway, leading to increased expression of several NF-κB–targeted genes (IκBα, plasminogen activator inhibitor 1, monocyte chemoattractant protein 1, IL-1β, and IL-6). Small interfering RNA–mediated knockdown of the serum and glucocorticoid-inducible kinase SGK1, a gene induced early in the response to aldosterone, but not pharmacologic inhibition of extracellular signal–regulated kinase and p38 kinase, attenuated aldosterone-induced NF-κB activation. Pharmacologic antagonism or knockdown of the mineralocorticoid receptor prevented aldosterone-induced NF-κB activity. In addition, activation of the glucocorticoid receptor inhibited the transactivation of NF-κB by aldosterone. In agreement with these in vitro findings, spironolactone prevented NF-κB–induced transcriptional activation observed in cortical collecting ducts of salt-restricted rats. In summary, aldosterone activates the canonical NF-κB pathway in principal cells of the cortical collecting duct by activating the mineralocorticoid receptor and by inducing SGK1. PMID:18987305

  12. Laparoscopic Transcystic Common Bile Duct Exploration: Advantages over Laparoscopic Choledochotomy

    PubMed Central

    Wang, Kai; Yuan, Rongfa; Xiong, Xiaoli; Wu, Linquan

    2016-01-01

    Purpose The ideal treatment for choledocholithiasis should be simple, readily available, reliable, minimally invasive and cost-effective for patients. We performed this study to compare the benefits and drawbacks of different laparoscopic approaches (transcystic and choledochotomy) for removal of common bile duct stones. Methods A systematic search was implemented for relevant literature using Cochrane, PubMed, Ovid Medline, EMBASE and Wanfang databases. Both the fixed-effects and random-effects models were used to calculate the odds ratio (OR) or the mean difference (MD) with 95% confidence interval (CI) for this study. Results The meta-analysis included 18 trials involving 2,782 patients. There were no statistically significant differences between laparoscopic choledochotomy for common bile duct exploration (LCCBDE) (n = 1,222) and laparoscopic transcystic common bile duct exploration (LTCBDE) (n = 1,560) regarding stone clearance (OR 0.73, 95% CI 0.50–1.07; P = 0.11), conversion to other procedures (OR 0.62, 95% CI 0.21–1.79; P = 0.38), total morbidity (OR 1.65, 95% CI 0.92–2.96; P = 0.09), operative time (MD 12.34, 95% CI −0.10–24.78; P = 0.05), and blood loss (MD 1.95, 95% CI −9.56–13.46; P = 0.74). However, the LTCBDE group showed significantly better results for biliary morbidity (OR 4.25, 95% CI 2.30–7.85; P<0.001), hospital stay (MD 2.52, 95% CI 1.29–3.75; P<0.001), and hospital expenses (MD 0.30, 95% CI 0.23–0.37; P<0.001) than the LCCBDE group. Conclusions LTCBDE is safer than LCCBDE, and is the ideal treatment for common bile duct stones. PMID:27668730

  13. The onset of turbulence in a square duct flow

    NASA Astrophysics Data System (ADS)

    Lemoult, Gregoire; Hof, Bjorn

    2014-11-01

    Wall bounded shear flows experience a sudden transition from a laminar state to turbulence as Reynolds number, Re , increases. K. Avila et al. (Science 333, 2011) recently characterized the onset of turbulence in pipe flow. They measured the probability for a localized disturbance to decay or spread and defined the critical Reynolds number, Rec , where the characteristic time for both process is equal. Using the same methodology, we measure these probabilities, decay and splitting, as a function of Re in a 1200 D long square duct, where D is the width of the duct. We found the expected exponential probability distribution for both processes which underlines their memoryless character. From the characteristic time of these distributions, we estimate the point where turbulence first becomes sustained in a square duct flow. The main difference with pipe flow is that the characteristic time at Rec is shorter making it more suitable for measurements of critical exponents in the framework of phase transition. These results also emphasize the universal behavior of the transition to turbulence in wall bounded shear flows.

  14. Theoretical models for duct acoustic propagation and radiation

    NASA Technical Reports Server (NTRS)

    Eversman, Walter

    1991-01-01

    The development of computational methods in acoustics has led to the introduction of analysis and design procedures which model the turbofan inlet as a coupled system, simultaneously modeling propagation and radiation in the presence of realistic internal and external flows. Such models are generally large, require substantial computer speed and capacity, and can be expected to be used in the final design stages, with the simpler models being used in the early design iterations. Emphasis is given to practical modeling methods that have been applied to the acoustical design problem in turbofan engines. The mathematical model is established and the simplest case of propagation in a duct with hard walls is solved to introduce concepts and terminologies. An extensive overview is given of methods for the calculation of attenuation in uniform ducts with uniform flow and with shear flow. Subsequent sections deal with numerical techniques which provide an integrated representation of duct propagation and near- and far-field radiation for realistic geometries and flight conditions.

  15. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    SciTech Connect

    Beach, R.; Burdick, A.

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance. IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations. These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.

  16. Input impedance in flow ducts: theory and measurement.

    PubMed

    Rodriguez, S; Gibiat, V; Lefebvre, A; Guilain, Stephane

    2012-09-01

    This paper presents both a theoretical and an experimental investigation of the influence of the mean flow on the input impedance of a duct. The input impedance of an axisymetrical flow duct is calculated, taking into account the convective effect of a uniform flow, the dissipative effect of a turbulent flow and the radiation in an open jet. Each of these effects is separately studied. An experimental apparatus has been specifically designed to lower flow noise on the transducers, taking advantage of the Two-Microphone-Three-Calibration (TMTC) method [V. Gibiat and F. Laloë, J. Acoust. Soc. Am. 88, 2533-2545 (1990)], whose full calibration process allows any geometry for the measurement head. Theory and experiments are compared for a 1 m long cylindrical duct carrying a flow whose Mach number equals up to 0.15. The resonant frequencies are in close agreement, within 3%. The relative evolution of the magnitude maxima with increasing flow are in good agreement, within 10%. Despite similar tendencies when modifying the mean flow velocity, the amplitude of variation of the magnitude is 2 to 5 times smaller in the experiments.

  17. Examination of Duct Physiology in the Human Mammary Gland

    PubMed Central

    Mills, Dixie; Gomberawalla, Ameer; Gordon, Eva J.; Tondre, Julie; Nejad, Mitra; Nguyen, Tinh; Pogoda, Janice M.; Rao, Jianyu; Chatterton, Robert; Henning, Susanne; Love, Susan M.

    2016-01-01

    Background The human breast comprise several ductal systems, or lobes, which contain a small amount of fluid containing cells, hormones, proteins and metabolites. The complex physiology of these ducts is likely a contributing factor to the development of breast cancer, especially given that the vast majority of breast cancers begin in a single lobular unit. Methods We examined the levels of total protein, progesterone, estradiol, estrone sulfate, dehydroepiandrosterone sulfate, and macrophages in ductal fluid samples obtained from 3 ducts each in 78 women, sampled twice over a 6 month period. Samples were processed for both cytological and molecular analysis. Intraclass correlation coefficients and mixed models were utilized to identify significant data. Results We found that the levels of these ductal fluid components were generally uncorrelated among ducts within a single breast and over time, suggesting that each lobe within the breast has a distinct physiology. However, we also found that estradiol was more correlated in women who were nulliparous or produced nipple aspirate fluid. Conclusions Our results provide evidence that the microenvironment of any given lobular unit is unique to that individual unit, findings that may provide clues about the initiation and development of ductal carcinomas. PMID:27073976

  18. Combined forced and free convection in a curved duct

    NASA Technical Reports Server (NTRS)

    Yam, Clement G.; Dwyer, Harry A.

    1992-01-01

    The purpose of this study is to investigate the flow and heat transfer characteristics of a combined forced and free convection flow in a curved duct. Solutions are obtained by solving the low Mach number model of the Navier-Stokes equation using a control volume method. The finite-volume method was developed with the use of a predictor-corrector numerical scheme and some new variations of the classical projection method. Solutions indicated that the existence of a buoyancy force has changed the entire flow structure inside a curved duct. Reversed flow at both inner and outer bend is observed. For moderate Reynolds number, the upstream section of the duct was significantly influenced by the free convection processes. In general, heat transfer is strong at the inner bend of the beginning of the heated section and at the outer bend on the last half of the heated section. The maximum velocity location is strongly influenced by the combined effects of buoyancy and centrifugal forces. A strong buoyancy force can reduce the strength of the secondary flow where it plays an important role in mixing.

  19. Congenital nasolacrimal duct fistula in Brown Swiss cattle

    PubMed Central

    2014-01-01

    Background An increased incidence of nasolacrimal duct fistula in the offspring of dam J and three of her sons (bulls A, B and C) prompted a study to investigate the prevalence and clinical manifestation of this anomaly. The dam J, bull B, 255 direct offspring of bulls A, B, and C and eight other direct and indirect offspring of cow J were examined. The periocular region of each animal was examined for unilateral or bilateral nasolacrimal duct fistula and the location, appearance and size of the lesions. Results Of 265 cattle examined, 54 had unilateral (n = 24) or bilateral fistula (n = 30). The prevalence of affected offspring differed significantly among the three bulls. The fistulae were located medial to the medial canthus of the eye and were 1 to 10 mm (median, 1 mm) in height and 1 to 12 mm (median, 2 mm) in length. The shape of the opening was circular in 58, oval in 23 and slit-like in three. One other animal had a large opening with an atypical shape and another had an abnormal medial canthus with several fistulous openings. Seventy openings were pigmented and 52 were hairless. The fistulae were clinically significant in 12 animals. Conclusions The findings suggest a hereditary cause of nasolacrimal duct fistula in Brown Swiss cattle. PMID:24548799

  20. Dynamics of compressible air flow in ducts with heat exchange

    NASA Astrophysics Data System (ADS)

    Abdulhadi, M.

    1986-12-01

    An investigation into the effect of heat addition on subsonic flow of an air stream in a constant-area duct preceded by a convergent nozzle is carried out. A nozzle flow apparatus with a heat exchanger encasing the constant-area duct has been built for this purpose. Hot water is provided from an electric boiler where the flow rate and the in-flow hot water temperature could be controlled. It is confirmed experimentally, as predicted analytically, that heat transfer to the gas decreases its local static pressure along the duct axis, and that this decrease is associated with an increase in Mach number toward M = 1 at the exit (thermal choking). In the case of subsonic flow, the additional entropy generated by the heat interaction exceeding the amount that produces thermal choking can only be accommodated by moving to a new Rayleigh line, at a decreased flow rate which lowers the inlet Mach number. The good correlation between the experimental results and the analytical derivations illustrates that the experimental arrangement has potential for further experiments and investigations.

  1. Mosaic lectin labelling in the quail collecting ducts.

    PubMed

    Menghi, G; Gabrielli, M G; Accili, D

    1995-04-01

    Morphological and histoenzymological differences have been observed between intercalated and principal cells of the quail Coturnix coturnix japonica collecting ducts. The present study was designed to shed light on the lectin affinity of the collecting duct cells within cortex and medulla by the use of HRP-labelled lectins combined with glycosidase degradation. Binding of PNA and RCA-I lectins consequent to enzymatic release of sialic acid revealed abundant sialylated carbohydrate moieties within the principal cell cytoplasm. This characteristic binding pattern differed considerably from the staining observed in the intercalated cells. Interesting information also emerged about the presence of sialoglycoconjugates having the terminal disaccharide sialic acid-beta-N-acetylgalactosamine originating from the increased SBA binding and the unmodified DBA labelling after removal of sialic acid. Sequential degradation by sialidase/beta-galactosidase followed by incubation with DBA offered the possibility to suspect that the receptor sugar for the penultimate beta-galactose may be N-acetylgalactosamine. Conversely, we were not able to define the accept sugar for penultimate beta-GalNAc owing to the lack of availability of beta-N-acetylgalactosaminidase enzyme. When although further studies are clearly needed to elucidate the physiological role of the cellular sialoglycoconjugates detected, the present results already provide valuable insight into the carbohydrate composition of intercalated and principal cells in the quail collecting ducts.

  2. Cholecystokinin cholescintigraphic findings in the cystic duct syndrome

    SciTech Connect

    Fink-Bennett, D.; DeRidder, P.; Kolozsi, W.; Gordon, R.; Rapp, J.

    1985-10-01

    Fourteen patients with a cystic duct syndrome (CDS) underwent cholecystokinin (CCK) cholescintigraphy. All patients presented with persistent postprandial right upper quadrant pain and biliary colic. None of the patients had an abnormal oral cholecystography, gallbladder (GB) ultrasound exam or upper GI series. Each patient received 5 mCi of technetium-99m disofenin. When the GB maximally filled, 0.02 microgram/kg CCK was administered (3 min) intravenously. Background corrected gallbladder ejection fractions (GBEFs) were determined every 5 min X 4 by rationing the pre-CCK GB counts minus post-CCK GB counts to pre-CCK GB counts. GBEFs were: 12% (3 patients), 17% (2), 0%, 1.3%, 3%, 4%, 6%, 11%, 14%, 18.5%, and 22% (1 each). All patients underwent a surgical exploration and all had macro- or microscopically abnormal cystic ducts with (12 patients) or without (2 patients) concomitant chronic cholecystitis. No patient with a partially occluded cystic duct with or without concomitant chronic cholecystitis had an ejection fraction that exceeded 22%. In an appropriate clinical setting, a low EF response to CCK should alert the physician to the presence of either chronic acalculous cholecystitis, CDS, or the combination of both.

  3. Mathematical analysis of mammary ducts in lactating human breast.

    PubMed

    Mortazavi, S Negin; Geddes, Donna; Hassiotou, Foteini; Hassanipour, Fatemeh

    2014-01-01

    This work studies a simple model for milk transport through lactating human breast ducts, and describes mathematically the mass transfer from alveolar sacs through the mammary ducts to the nipple. In this model both the phenomena of diffusion in the sacs and conventional flow in ducts have been considered. The ensuing analysis reveals that there is an optimal range of bifurcation numbers leading to the easiest milk flow based on the minimum flow resistance. This model formulates certain difficult-to-measure values like diameter of the alveolar sacs, and the total length of the milk path as a function of easy-to-measure properties such as milk fluid properties and macroscopic measurements of the breast. Alveolar dimensions from breast tissues of six lactating women are measured and reported in this paper. The theoretically calculated alveoli diameters for optimum milk flow (as a function of bifurcation numbers) show excellent match with our biological data on alveolar dimensions. Also, the mathematical model indicates that for minimum milk flow resistance the glandular tissue must be within a short distance from the base of the nipple, an observation that matches well with the latest anatomical and physiological research.

  4. Advances in cholangiocyte immunobiology

    PubMed Central

    Syal, Gaurav; Fausther, Michel

    2012-01-01

    Cholangiocytes, or bile duct epithelia, were once thought to be the simple lining of the conduit system comprising the intra- and extrahepatic bile ducts. Growing experimental evidence demonstrated that cholangiocytes are in fact the first line of defense of the biliary system against foreign substances. Experimental advances in recent years have unveiled previously unknown roles of cholangiocytes in both innate and adaptive immune responses. Cholangiocytes can release inflammatory modulators in a regulated fashion. Moreover, they express specialized pattern-recognizing molecules that identify microbial components and activate intracellular signaling cascades leading to a variety of downstream responses. The cytokines secreted by cholangiocytes, in conjunction with the adhesion molecules expressed on their surface, play a role in recruitment, localization, and modulation of immune responses in the liver and biliary tract. Cholangiocyte survival and function is further modulated by cytokines and inflammatory mediators secreted by immune cells and cholangiocytes themselves. Because cholangiocytes act as professional APCs via expression of major histocompatibility complex antigens and secrete antimicrobial peptides in bile, their role in response to biliary infection is critical. Finally, because cholangiocytes release mediators critical to myofibroblastic differentiation of portal fibroblasts and hepatic stellate cells, cholangiocytes may be essential in the pathogenesis of biliary cirrhosis. PMID:22961800

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

    NASA Technical Reports Server (NTRS)

    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.

  6. Heat Transfer Computations of Internal Duct Flows With Combined Hydraulic and Thermal Developing Length

    NASA Technical Reports Server (NTRS)

    Wang, C. R.; Towne, C. E.; Hippensteele, S. A.; Poinsatte, P. E.

    1997-01-01

    This study investigated the Navier-Stokes computations of the surface heat transfer coefficients of a transition duct flow. A transition duct from an axisymmetric cross section to a non-axisymmetric cross section, is usually used to connect the turbine exit to the nozzle. As the gas turbine inlet temperature increases, the transition duct is subjected to the high temperature at the gas turbine exit. The transition duct flow has combined development of hydraulic and thermal entry length. The design of the transition duct required accurate surface heat transfer coefficients. The Navier-Stokes computational method could be used to predict the surface heat transfer coefficients of a transition duct flow. The Proteus three-dimensional Navier-Stokes numerical computational code was used in this study. The code was first studied for the computations of the turbulent developing flow properties within a circular duct and a square duct. The code was then used to compute the turbulent flow properties of a transition duct flow. The computational results of the surface pressure, the skin friction factor, and the surface heat transfer coefficient were described and compared with their values obtained from theoretical analyses or experiments. The comparison showed that the Navier-Stokes computation could predict approximately the surface heat transfer coefficients of a transition duct flow.

  7. Effect of Ducting on Radio Occultation Measurements: An Assessment Based on High-Resolution Radiosonde Soundings

    NASA Technical Reports Server (NTRS)

    Ao, C. O

    2007-01-01

    Recent studies have shown that the presence of elevated ducts in the lower atmosphere has an adverse effect on the inversion of GPS radio occultation data. The problem arises because the microwave refractivity within and below an elevated duct is no longer uniquely determined by the bending angle profile. Applying Abel inversion without a priori knowledge of the duct will introduce a negative bias in the retrieved refractivity profile within and below the duct. In this work, high vertical resolution radiosonde data are used to give a quantitative assessment of the characteristics and effects of ducts, including their frequency of occurrences, heights, and thicknesses at different latitudes and seasons. The negative bias from the Abel-retrieved refractivity profiles resulting from these ducts is also computed. The results give a strong indication that ducting in the lower troposphere is a frequent phenomenon over the tropics and midlatitudes. The ducts are shown to be predominantly caused by sharp changes in the vertical structure of water vapor. The majority of the ducts are found to be below 2 km, with a median duct layer thickness of about 100 m. The negative refractivity bias is shown to be largest below 2 km, with a median value of about 0.5-1% in the tropics and 0.2-0.5% in midlatitudes. The bias is about a factor of 2-3 smaller between 2 to 3 km and is negligible above 4 km.

  8. Assessment of Chronological Effects of Irreversible Electroporation on Hilar Bile Ducts in a Porcine Model

    SciTech Connect

    Choi, Jae Woong Lu, David S. K. Osuagwu, Ferdnand Raman, Steven; Lassman, Charles

    2013-11-07

    PurposeTo evaluate the chronological effects of irreversible electroporation (IRE) on large hilar bile ducts in an in vivo porcine model correlated with computed tomography (CT) cholangiography and histopathology.Materials and MethodsTwelve IRE zones were made along hilar bile ducts intraoperatively under ultrasound (US)-guidance in 11 pigs. Paired electrodes were placed either on opposing sides of the bile duct (straddle [STR]) or both on one side of the bile duct (one-sided [OSD]). The shortest electrode-to-duct distance was classified as periductal (≤2 mm) or nonperiductal (>2 mm). CT cholangiography and laboratory tests were performed before IRE and again at 2 days, 4 weeks, and 8 weeks after IRE. Degree of bile duct injury were graded as follows: grade 0 = no narrowing; grade 1 = ≤50 % duct narrowing; grade 2 = >50 % narrowing without proximal duct dilatation; grade 3 = grade 2 with proximal duct dilatation; and grade 4 = grade 3 with enzyme elevation. Pigs were selected for killing and histopathology at 2 days, 4, and 8 weeks.ResultsNonperiductal electrode placement produced no long-term strictures in 5 of 5 ducts. Periductal electrode placement produced mild narrowing in 6 of 7 ducts: 5 grade 1 and 1 grade 2. None showed increased enzymes. There was no significant difference between STR versus OSD electrode placement. Histopathology showed minor but relatively greater ductal mural changes in narrowed ducts.ConclusionIn the larger hilar ducts, long-term patency and mural integrity appear resistant to IRE damage with the energy deposition used, especially if the electrode is not immediately periductal in position.

  9. Device for Measuring Low Flow Speed in a Duct

    NASA Technical Reports Server (NTRS)

    Quinn, Frank; Magee, Kevin

    2009-01-01

    A multiple-throat venturi system has been invented for measuring laminar flow of air or other gas at low speed (1 to 30 cm/s) in a duct while preserving the laminar nature of the flow and keeping the velocity profile across the duct as nearly flat as possible. While means for measuring flows at higher speeds are well established, heretofore, there have been no reliable means for making consistent, accurate measurements in this speed range. In the original application for which this system was invented, the duct leads into the test section of a low-speed wind tunnel wherein uniform, low-speed, laminar flow is required for scientific experiments. The system could also be used to monitor a slow flow of gas in an industrial process like chemical vapor deposition. In the original application, the multiple- throat venturi system is mounted at the inlet end of the duct having a rectangular cross section of 19 by 14 cm, just upstream of an assembly of inlet screens and flow straighteners that help to suppress undesired flow fluctuations (see Figure 1). The basic venturi measurement principle is well established: One measures the difference in pressure between (1) a point just outside the inlet, where the pressure is highest and the kinetic energy lowest; and (2) the narrowest part (the throat) of the venturi passage, where the kinetic energy is highest and the pressure is lowest. Then by use of Bernoulli s equation for the relationship between pressure and kinetic energy, the volumetric flow speed in the duct can be calculated from the pressure difference and the inlet and throat widths. The design of this system represents a compromise among length, pressure recovery, uniformity of flow, and complexity of assembly. Traditionally, venturis are used to measure faster flows in narrower cross sections, with longer upstream and downstream passages to maintain accuracy. The dimensions of the passages of the present venturi system are sized to provide a readily measurable

  10. Lymph flow pattern in the intact thoracic duct in sheep.

    PubMed

    Onizuka, M; Flatebø, T; Nicolaysen, G

    1997-08-15

    1. To study the lymph flow dynamics in the intact thoracic duct, we applied an ultrasound transit-time flow probe in seven anaesthetized and four unanaesthetized adult sheep (approximately 60 kg). In unanaesthetized non-fasting animals we found that lymph flow in the thoracic duct was always regular pulsatile (pulsation frequency, 5.2 +/- 0.8 min-1) with no relation to heart or respiratory activity. At baseline the peak level of the thoracic duct pulse flow was 11.6-20.7 ml min-1 with a nadir of 0-3.6 ml min-1. Mean lymph flow was 5.4 +/- 3.1 ml min-1. The flow pattern of lymph in the thoracic duct was essentially the same in the anaesthetized animals. 2. In both the anaesthetized and unanaesthetized animals, the lymph flow response to a stepwise increase in the outflow venous pressure showed interindividual variation. Some were sensitive to any increase in outflow venous pressure, but others were resistant in that lymph flow did not decrease until outflow venous pressure was increased to higher levels. This resistance was also observed in the high lymph flow condition produced by fluid infusion in the anaesthetized animal and mechanical constriction of the caudal vena cava in the unaesthetized animals. Pulsation frequency of the thoracic duct flow initially increased and then decreased with a stepwise increase in the outflow venous pressure. This initial increase might be a compensatory response to maintain lymph flow against elevated outflow venous pressure. 3. To test the effect of long-term outflow venous pressure elevation in unanaesthetized sheep, outflow venous pressure was increased by inflation of a cuff around the cranial vena cava for 1, 5 or 25 h. The cuff was inflated to a level where lymph flow was reduced. Lymph flow remained low or decreased further during the entire cuff-inflation period. We calculated the lymph debt caused by the outflow venous pressure elevation and the amount 'repaid' when venous pressure returned to normal. Lymph debt for 25 h

  11. Lymph flow pattern in the intact thoracic duct in sheep.

    PubMed Central

    Onizuka, M; Flatebø, T; Nicolaysen, G

    1997-01-01

    1. To study the lymph flow dynamics in the intact thoracic duct, we applied an ultrasound transit-time flow probe in seven anaesthetized and four unanaesthetized adult sheep (approximately 60 kg). In unanaesthetized non-fasting animals we found that lymph flow in the thoracic duct was always regular pulsatile (pulsation frequency, 5.2 +/- 0.8 min-1) with no relation to heart or respiratory activity. At baseline the peak level of the thoracic duct pulse flow was 11.6-20.7 ml min-1 with a nadir of 0-3.6 ml min-1. Mean lymph flow was 5.4 +/- 3.1 ml min-1. The flow pattern of lymph in the thoracic duct was essentially the same in the anaesthetized animals. 2. In both the anaesthetized and unanaesthetized animals, the lymph flow response to a stepwise increase in the outflow venous pressure showed interindividual variation. Some were sensitive to any increase in outflow venous pressure, but others were resistant in that lymph flow did not decrease until outflow venous pressure was increased to higher levels. This resistance was also observed in the high lymph flow condition produced by fluid infusion in the anaesthetized animal and mechanical constriction of the caudal vena cava in the unaesthetized animals. Pulsation frequency of the thoracic duct flow initially increased and then decreased with a stepwise increase in the outflow venous pressure. This initial increase might be a compensatory response to maintain lymph flow against elevated outflow venous pressure. 3. To test the effect of long-term outflow venous pressure elevation in unanaesthetized sheep, outflow venous pressure was increased by inflation of a cuff around the cranial vena cava for 1, 5 or 25 h. The cuff was inflated to a level where lymph flow was reduced. Lymph flow remained low or decreased further during the entire cuff-inflation period. We calculated the lymph debt caused by the outflow venous pressure elevation and the amount 'repaid' when venous pressure returned to normal. Lymph debt for 25 h

  12. Clad and duct materials property needs for sodium fast reactors: US perspective

    SciTech Connect

    Maloy, Stuart A

    2009-01-01

    In the Advanced Fuel Cycle Initiative, the clad and duct materials property needs are driven by the program direction of using a fast reactor to transmute minor actinides. To economically perform transmutation requires fuels to be irradiated to at least 200/0 burnup before discharge and recycle. The cladding materials used in sllch high dose irradiations will experience at least 200 dpa of exposure. The requirements are that the cladding must contain the fuel until discharge and the duct must maintain ductility and mechanical strength to direct the sodium coolant and withdraw the fuel at discharge. Presently, achieving a bumup of 20% in fast reactor fuels is a significant challenge. The materials property needs for clad materials are the following in order of importance: (1) Radiation resistance: the material must be tolerant of radiation damage up to 200 dpa or greater depending on the final burnup desired at temperatures ranging from 350-600 C (temperature range for maximum dose is 400-500 C). Thus, the material must be tolerant of swelling, irradiation creep, and embrittlement effects. (2) Mechanical properties: tensile properties (strength, ductility), creep resistance, fracture toughness and fatigue resistance must all sufficient to contain the fuel during irradiation and discharge. (3) Fuel Clad Chemical Interaction: the cladding must be resistant to chemical interaction with the fuel during irradiation to prevent clad failure. (4) Fabrication and joining: the material must be able to be fabricated into component parts and joined to contain the fuel during the irradiation and during discharge. (5) Corrosion resistance: the material must be tolerant of the sodium coolant, with minimal corrosion rate. (6) Reprocessing: the cladding must be dissolvable to enable fuel reprocessing. (7) Long-term stability: the clad and duct materials must be stable through 6 or more years of irradiation depending on the final fuel burnup desired. (8) Thermal properties: thermal

  13. Primary Treatment of Nasolacrimal Duct Obstruction with Nasolacrimal Duct Intubation in Children Less than Four Years Old

    PubMed Central

    Repka, Michael X.; Melia, B. Michele; Beck, Roy W.; Atkinson, C. Scott; Chandler, Danielle L.; Holmes, Jonathan M.; Khammar, Alexander; Morrison, David; Quinn, Graham E.; Silbert, David I.; Ticho, Benjamin H.; Wallace, David K.; Weakley, David R.

    2008-01-01

    Purpose To report the outcome of nasolacrimal duct intubation as the primary treatment of congenital nasolacrimal duct obstruction (NLDO) in children less than 4 years of age. Methods 182 eyes of 139 children receiving intubation with planned tube retention for 2 to 5 months were enrolled in a prospective, non-randomized observational multicenter study (19 sites). Children were aged 6 to <45 months at the time of surgery, with no prior nasolacrimal surgical procedure, and had at least one of the following clinical signs of NLDO: epiphora, mucous discharge and/or increased tear lake. Results Treatment success was defined as absence of epiphora, mucous discharge and increased tear lake at the outcome visit one month after tube removal. The surgical outcome was assessed in 150 eyes (82% of cohort). The proportion of eyes treated successfully was 91% (95% confidence interval = 86% to 95%). The outcome dye disappearance test was normal in 125 (86%) eyes, indeterminate in 13 (9%), and abnormal in 7 (5%) of the 145 eyes tested. Monocanalicular tubes were used in 74% of cases. The tube was removed prior to the planned minimum retention time of months in 61 eyes (41%). For 23 eyes the early removal was due to inadvertent displacement by the patient. Conclusion In children 6 to <45 months of age, nasolacrimal duct intubation in a non-randomized and non-comparative trial was a successful primary treatment of NLDO in about 90% of cases not lost to follow up. PMID:18595756

  14. Structure and function of the major ampullate spinning duct of the golden orb weaver, Nephila edulis.

    PubMed

    Davies, G J G; Knight, D P; Vollrath, F

    2013-10-01

    Silks are fibres produced by spiders, some insects and even a crustacean, and are formed from protein solution by a pulltrusion process that is not well understood. Here we describe three aspects of the functional anatomy of the spinning apparatus in a spider: (i) changes in the diameter of the duct of the silk gland along its length for individuals at different stages of development, (ii) the correlation between the morphology of the duct and size and (iii) changes in the thickness of the wall of the duct. We conclude that in the distal part of the duct both the lumen's geometry and change in diameter with distance remains remarkably constant as the duct increases in length from moult to moult as the spider grows. This suggests constancy in the region where the nascent silk filament is drawn down within the lumen of the duct, which is likely to be fundamental for forming strong and tough fibres.

  15. Uniqueness of transonic shock solutions in a duct for steady potential flow

    NASA Astrophysics Data System (ADS)

    Chen, Gui-Qiang; Yuan, Hairong

    We study the uniqueness of solutions with a transonic shock in a duct in a class of transonic shock solutions, which are not necessarily small perturbations of the background solution, for steady potential flow. We prove that, for given uniform supersonic upstream flow in a straight duct, there exists a unique uniform pressure at the exit of the duct such that a transonic shock solution exists in the duct, which is unique modulo translation. For any other given uniform pressure at the exit, there exists no transonic shock solution in the duct. This is equivalent to establishing a uniqueness theorem for a free boundary problem of a partial differential equation of second order in a bounded or unbounded duct. The proof is based on the maximum/comparison principle and a judicious choice of special transonic shock solutions as a comparison solution.

  16. Laser velocimeter and total pressure measurements in circular-to-rectangular transition ducts

    NASA Technical Reports Server (NTRS)

    Patrick, William P.; Mccormick, Duane C.

    1988-01-01

    A comprehensive set of total pressure and three-component laser velocimetry (LV) data were obtained within two circular-to-rectangular transition ducts at low subsonic speeds. This set of reference data was acquired for use in identifying secondary flow mechanisms and for assessing the accuracy of computational procedures for calculating such flows. Data were obtained at the inlet and exit planes of an aspect ratio three duct having a length-to-diameter ratio of one (AR310) and an aspect ratio six duct having a length-to-diameter ratio of three (AR630). Each duct was unseparated throughout its transition section. It is therefore concluded that secondary flows can play an important part in the fluid dynamics of transition ducts and needs to be addressed in computational analysis. The strength of the secondary flows depends on both the aspect ratio and relative axial duct length.

  17. The dangers of using stapling devices for cystic duct closure in laparoscopic cholecystectomy.

    PubMed

    Belgaumkar, Ajay P; Carswell, Kirstin A; Chang, Avril; Patel, Ameet G

    2009-10-01

    Laparoscopic stapling devices are used widely in laparoscopic surgery, for division of vessels and creation of anastomoses. Their use in the division of a widened cystic duct at laparoscopic cholecystectomy has been reported earlier. We present 3 different complications occurring after division of the cystic duct using the EndoGIA stapling device. A review of the literature has been performed and safe alternative techniques for laparoscopic ligation of the cystic duct are proposed.

  18. Thermionic nuclear reactor with internal heat distribution and multiple duct cooling

    DOEpatents

    Fisher, C.R.; Perry, L.W. Jr.

    1975-11-01

    A Thermionic Nuclear Reactor is described having multiple ribbon-like coolant ducts passing through the core, intertwined among the thermionic fuel elements to provide independent cooling paths. Heat pipes are disposed in the core between and adjacent to the thermionic fuel elements and the ribbon ducting, for the purpose of more uniformly distributing the heat of fission among the thermionic fuel elements and the ducts.

  19. Inadvertent Puncture of the Thoracic Duct During Attempted Central Venous Catheter Placement

    SciTech Connect

    Teichgraber, Ulf K.M. Nibbe, Lutz; Gebauer, Bernhard; Wagner, Hans-Joachim

    2003-11-15

    We report a case of puncture of the thoracic duct during left subclavian vein catheterization on the intensive care unit. Computed tomography and measurement of the triglyceride levels in the aspirated fluid proved the inadvertent penetration of the guidewire into the thoracic duct. Early recognition of central line misplacement avoided serious complications. Inadvertent central venous catheter placement into the thoracic duct may have the potential complications of infusion mediastinum and chylothorax.

  20. Velocity, temperature, and electrical conductivity profiles in hydrogen-oxygen MHD duct flows

    NASA Technical Reports Server (NTRS)

    Greywall, M. S.; Pian, C. C. P.

    1978-01-01

    Two-dimensional duct flow computations for radial distributions of velocity, temperature, and electrical conductivity are reported. Calculations were carried out for the flow conditions representative of a hydrogen-oxygen combustion driven MHD duct. Results are presented for: profiles of developing flow in a smooth duct, and for profiles of fully developed pipe flow with a specified streamwise shear stress distribution. The predicted temperature and electrical conductivity profiles for the developing flows compare well with available experimental data.

  1. Ducted Gravity Wave Propagation in the Dynamic Mesosphere and Lower Thermosphere

    NASA Astrophysics Data System (ADS)

    Snively, J. B.; Hickey, M. P.; Walterscheid, R. L.

    2012-12-01

    Ducted gravity waves are commonly observed in the mesosphere and lower thermosphere (MLT) region; airglow data reveal typical horizontal wavelengths of ˜15-35 km and periods of ˜4-8 minutes [e.g., textit{Simkhada et al.}, Ann. Geophys., 27, 3213, 2009]. Typical airglow intensity perturbations suggest amplitudes on the order of a few to tens of Kelvin [textit{Snively et al.}, JGR, 115, A11311, 2010]; radar measurements have identified ducted wave wind perturbations on the order of a few to tens of m/s [e.g., textit{Fritts and Janches}, JGR, 113, D05112, 2008]. Waves become trapped by the combination of thermal and wind structure, and propagate as ideal ducted modes [textit{Walterscheid and Hickey}, 114, D19109, 2009] and non-ideal ducted wave packets that effectively ``bounce'' between layered regions of evanescence [textit{Yu and Hickey}, GRL, 34, L02821, 2007]. Here, we investigate the effects of time-varying MLT region structure on the trapping of ducted waves, and the transfer of energy between ideal ducted modes and non-ideally ducted or freely-propagating wave packets. Using first a steady-state 1D full-wave model to identify available duct modes and their dispersion curves, we investigate the evolutions of duct environments occurring within the MLT as they vary over time scales of several hours. Specific case studies are constructed within a 2D nonlinear compressible model, to investigate the time-dependent tuning and de-tuning of MLT-region ducts, and the transfers of energy to and from ducted modes. Results suggest that the dynamic and variable structure of the MLT region modulates the observability of ducted waves that may be seen in airglow data, while also contributing to the redistribution, and occasional dissipation, of gravity waves at these short periods.

  2. Imaging of the pancreas: Recent advances

    PubMed Central

    Chaudhary, Vikas; Bano, Shahina

    2011-01-01

    A wide spectrum of anomalies of pancreas and the pancreatic duct system are commonly encountered at radiological evaluation. Diagnosing pancreatic lesions generally requires a multimodality approach. This review highlights the new advances in pancreatic imaging and their applications in the diagnosis and management of pancreatic pathologies. The mainstay techniques include computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), radionuclide imaging (RNI) and optical coherence tomography (OCT). PMID:21847450

  3. Experiments on the Recovery of Waste Heat in Cooling Ducts, Special Report

    NASA Technical Reports Server (NTRS)

    Silverstein, Abe

    1939-01-01

    Tests have been conducted in the N.A.C.A. full-scale wind tunnel to investigate the partial recovery of the heat energy which is apparently wasted in the cooling of aircraft engines. The results indicate that if the radiator is located in an expanded duct, a part of the energy lost in cooling is recovered; however, the energy recovery is not of practical importance up to airplane speeds of 400 miles per hour. Throttling of the duct flow occurs with heated radiators and must be considered in designing the duct outlets from data obtained with cold radiators in the ducts.

  4. An experimental comparison of nonswirling and swirling flow in a circular-to-rectangular transition duct

    NASA Technical Reports Server (NTRS)

    Reichert, B. A.; Hingst, W. R.; Okiishi, T. H.

    1991-01-01

    Circular-to-rectangular transition ducts are used as exhaust system components of aircraft with rectangular exhaust nozzles. Often, the incoming flow of these transition ducts includes a swirling velocity component remaining from the gas turbine engine. Previous transition duct studies have either not included inlet swirl or when inlet swirl was considered, only overall performance parameters were evaluated. Circular-to-rectangular transition duct flows with and without inlet swirl were explored in order to understand the effect of inlet swirl on the transition duct flow field and to provide detailed duct flow data for comparison with numerical code predictions. A method was devised to create a swirling, solid body rotational flow with minimal associated disturbances. Coefficients based on velocities and total and static pressures measured incross stream planes at four axial locations within the transition duct, along with surface static pressure measurements and surface oil film visualization, are presented for both nonswirling and swirling incoming flow. In both cases the inlet centerline Mach number was 0.35. The Reynolds number based on the inlet centerline velocity and duct inlet diameter was 1,547,000 for nonswirling and 1,366,000 for swirling flow. The maximum swirl angle was 15.6 deg. Two pair of counter-rotating side wall vortices appeared in the duct flow without inlet swirl. These vortices were absent in the swirling incoming flow cases.

  5. The statistical evaluation of duct tape end match as physical evidence

    NASA Astrophysics Data System (ADS)

    Chan, Ka Lok

    Duct tapes are often submitted to crime laboratories as evidence associated with abductions, homicides, or construction of explosive devices. As a result, trace evidence examiners are often asked to analyze and compare commercial duct tapes so that they can establish possible evidentiary links. Duct tape end matches are believed to be the strongest association between exemplar and question samples because they are considered as evidence with unique individual characteristics. While end match analysis and comparison have long been undertaken by trace evidence examiners, there is a significant lack of scientific research for associating two or more segments of duct tapes. This study is designed to obtain statistical inferences on the uniqueness of duct tape tears. Three experiments were devised to compile the basis for a statistical assessment of the probability of duct tape end matches along with a proposed error rate. In one experiment, we conducted the equivalent of 10,000 end match examinations with an error rate of 0%. In the second experiment, we performed 2,704 end match examinations having 0% error rate. In the third experiment, using duct tape by an Elmendorf Tear tester, we conducted 576 end match examinations with an error rate of 0% and having all samples correctly associated. The results of this study indicate that end matches are distinguishable among a single roll of duct tape and between two different rolls of duct tape having very similar surface features and weave pattern.

  6. Preliminary Full-Scale Wind-Tunnel Investigation of Wing Ducts for Radiators, Special Report

    NASA Technical Reports Server (NTRS)

    Silverstein, Abe; Nickle, F. R.

    1938-01-01

    Wing ducts for liquid-cooled engine radiators have been investigated in the N.A.C.A. full-scale wind tunnel on a large model airplane. Th e tests were made to determine the relative merits of several types of duct and radiator installations for an airplane of a particular des ign. In the test program the principal duct dimensions were system atically varied, and the results are therefore somewhat applicable to the general problems of wing duct design, although they should be co nsidered as preliminary and only indicative of the inherent possibil ities.

  7. Zebrafish sox9b is crucial for hepatopancreatic duct development and pancreatic endocrine cell regeneration

    PubMed Central

    Manfroid, Isabelle; Ghaye, Aurelie; Naye, François; Detry, Nathalie; Palm, Sarah; Pan, Luyuan; Ma, Taylur P.; Huang, Wei; Rovira, Meritxell; Martial, Joseph A.; Parsons, Michael J.; Moens, Cecilia B.; Voz, Marianne L.; Peers, Bernard

    2012-01-01

    Recent zebrafish studies have shown that the late appearing pancreatic endocrine cells derive from pancreatic ducts but the regulatory factors involved are still largely unknown. Here, we show that the zebrafish sox9b gene is expressed in pancreatic ducts where it labels the pancreatic Notch-responsive cells previously shown to be progenitors. Inactivation of sox9b disturbs duct formation and impairs regeneration of beta cells from these ducts in larvae. sox9b expression in the midtrunk endoderm appears at the junction of the hepatic and ventral pancreatic buds and, by the end of embryogenesis, labels the hepatopancreatic ductal system as well as the intrapancreatic and intrahepatic ducts. Ductal morphogenesis and differentiation are specifically disrupted in sox9b mutants, with the dysmorphic hepatopancreatic ducts containing misdifferentiated hepatocyte-like and pancreatic-like cells. We also show that maintenance of sox9b expression in the extrapancreatic and intrapancreatic ducts requires FGF and Notch activity, respectively, both pathways known to prevent excessive endocrine differentiation in these ducts. Furthermore, beta cell recovery after specific ablation is severely compromised in sox9b mutant larvae. Our data position sox9b as a key player in the generation of secondary endocrine cells deriving from pancreatic ducts in zebrafish. PMID:22537488

  8. Screech tones from free and ducted supersonic jets

    NASA Astrophysics Data System (ADS)

    Tam, C. K. W.; Ahuja, K. K.; Jones, R. R., III

    1994-05-01

    It is well known that screech tones from supersonic jets are generated by a feedback loop. The loop consists of three main components. They are the downstream propagating instability wave, the shock cell structure in the jet plume, and the feedback acoustic waves immediately outside the jet. Evidence will be presented to show that the screech frequency is largely controlled by the characteristics of the feedback acoustic waves. The feedback loop is driven by the instability wave of the jet. Thus the tone intensity and its occurrence are dictated by the characteristics of the instability wave. In this paper the dependence of the instability wave spectrum on the azimuthal mode number (axisymmetric or helical/flapping mode, etc.), the jet-to-ambient gas temperature ratio, and the jet Mach number are studied. The results of this study provide an explanation for the observed screech tone mode switch phenomenon (changing from axisymmetric to helical mode as Mach number increases) and the often-cited experimental observation that tone intensity reduces with increase in jet temperature. For ducted supersonic jets screech tones can also be generated by feedback loops formed by the coupling of normal duct modes to instability waves of the jet. The screech frequencies are dictated by the frequencies of the duct modes. Super resonance, resonance involving very large pressure oscillations, can occur when the feedback loop is powered by the most amplified instability wave. It is proposed that the observed large amplitude pressure fluctuations and tone in the test cells of Arnold Engineering Development Center were generated by super resonance. Estimated super-resonance frequency for a Mach 1.3 axisymmetric jet tested in the facility agrees well with measurement.

  9. Idiopathic duct-centric pancreatitis (IDCP) with immunological studies.

    PubMed

    Kusuda, Takeo; Uchida, Kazushige; Satoi, Sohei; Koyabu, Masanori; Fukata, Norimasa; Miyoshi, Hideaki; Ikeura, Tsukasa; Sakaguchi, Yutaku; Yoshida, Katsunori; Fukui, Toshiro; Shimatani, Masaaki; Matsushita, Mitsunobu; Takaoka, Makoto; Nishio, Akiyoshi; Uemura, Yoshiko; Kwon, A-Hon; Okazaki, Kazuichi

    2010-01-01

    A 65-year-old woman with elevated serum levels of pancreatic enzymes was referred to our hospital for further examinations. Abdominal US and contrast-enhanced CT demonstrated swelling of the pancreas body and tail. MRCP and ERCP revealed abrupt ending of the MPD in the pancreas body. Under the suspicion of malignancy, distal pancreatectomy and splenectomy were performed. The histopathological findings showed idiopathic duct-centric pancreatitis (IDCP) with granulocytic epithelial lesions (GEL). As most cases of Japanese autoimmune pancreatitis (AIP) are lymphoplasmacytic sclerosing pancreatitis (LPSP), the present case seems to be helpful to clarify the clinical findings of IDCP in Japan. PMID:21139294

  10. Early somatostatinoma of the papilla of the duct of Santorini.

    PubMed

    Malone, M J; Silverman, M L; Braasch, J W; Jin, G L; Dayal, Y

    1985-12-01

    We studied a patient with a very small somatostatinoma that arose from the prominence of the orifice of the duct of Santorini. The patient presented clinically with epigastric discomfort, marked loss of weight, diarrhea, exertional dyspnea, and chest pain. He flushed intermittently and had occasional tachycardia and hypertension. Levels of serum serotonin and urinary 5-hydroxyindoleacetic acid were normal. A small ampullary tumor was resected and identified by immunohistochemical staining to be a somatostatinoma. The patient had gained 6.75 kg and was essentially free of symptoms 16 months after surgery.

  11. Inflammatory Myofibroblastic Tumor of Common Bile Duct in a Girl.

    PubMed

    D'Cunha, Aureen; Jehangir, Susan; Thomas, Reju

    2016-01-01

    Inflammatory myofibroblastic tumor (IMT) is a rare, low grade malignant lesion which can occur anywhere in the body. In children it is usually found in the visceral soft tissues with a potential for local invasion and recurrence, and rarely distant metastasis. We report the diagnostic dilemma faced in the management of a 12-year old girl who presented with obstructive jaundice with a mass lesion at the distal end of the common bile duct. She underwent a tumor resection with a bilio-enteric bypass followed by a course of oral steroids and celecoxib.

  12. Inflammatory Myofibroblastic Tumor of Common Bile Duct in a Girl

    PubMed Central

    Jehangir, Susan; Thomas, Reju

    2016-01-01

    Inflammatory myofibroblastic tumor (IMT) is a rare, low grade malignant lesion which can occur anywhere in the body. In children it is usually found in the visceral soft tissues with a potential for local invasion and recurrence, and rarely distant metastasis. We report the diagnostic dilemma faced in the management of a 12-year old girl who presented with obstructive jaundice with a mass lesion at the distal end of the common bile duct. She underwent a tumor resection with a bilio-enteric bypass followed by a course of oral steroids and celecoxib. PMID:27672578

  13. Steady flow OF non-Newtonian fluids through rectangular ducts

    SciTech Connect

    Gao, S.X.; Hartnett, J.P. )

    1993-03-01

    The present paper contains a numerical study for the secondary flow of a Reiner-Rivlin non-Newtonian fluid in laminar flow through ducts of square and rectangular cross section. Finite difference methods are developed to obtain the primary flow, the secondary flow, and friction factor. The influence of the second normal stress coefficient, the Reynolds number, and the aspect ratio on the magnitude of the secondary flow are considered. In general, the effect of the secondary flow on the primary flow rate and friction factor is found to be negligible.

  14. Portal annular pancreas: the pancreatic duct ring sign on MRCP

    PubMed Central

    Lath, Chinar O.; Agrawal, Dilpesh S.; Timins, Michael E.; Wein, Melissa M.

    2015-01-01

    Portal annular pancreas is a rare pancreatic variant in which the uncinate process of the pancreas extends and fuses to the dorsal surface of the body of the pancreas by surrounding the portal vein. It is asymptomatic, but it can be mistaken for a pancreatic head mass on imaging and could also have serious consequences during pancreatic surgery, if unrecognized. We report this case of a 53-year-old female patient who was diagnosed to have portal annular pancreas on the basis of an unusual course (ring appearance) of the main pancreatic duct on magnetic resonance cholangiopancreatography, not described earlier in the radiology literature. PMID:26649117

  15. Histopathological case report of high grade salivary duct carcinoma.

    PubMed

    Borovec, Jiri; Cegan, Martin; Mala, Katerina; Harmash, Natalia; Chramosta, Petr; Kobierzycki, Christopher; Bobek, Vladimir

    2015-01-01

    The case of a 39-year-old man with slowly growing mass in the superior part of left parotid region is described. Patient presented neurological symptoms including hypomobility of lower left eyelid and inability of complete closure of left side eyelids resulting in conjunctivitis and hyperlacrimation. Routine physical examination supported by image and laboratory tests was performed. Pathomorphological results of hematoxylin and eosin staining as well immunohistochemical examination in view of clinical presentation pointed to diagnosis of high grade salivary duct carcinoma. Rare incidence, histological view similar to breast cancer and body localization are sufficient reasons for further analyses and descriptions of this type of lesions. PMID:26691893

  16. Inflammatory Myofibroblastic Tumor of Common Bile Duct in a Girl.

    PubMed

    D'Cunha, Aureen; Jehangir, Susan; Thomas, Reju

    2016-01-01

    Inflammatory myofibroblastic tumor (IMT) is a rare, low grade malignant lesion which can occur anywhere in the body. In children it is usually found in the visceral soft tissues with a potential for local invasion and recurrence, and rarely distant metastasis. We report the diagnostic dilemma faced in the management of a 12-year old girl who presented with obstructive jaundice with a mass lesion at the distal end of the common bile duct. She underwent a tumor resection with a bilio-enteric bypass followed by a course of oral steroids and celecoxib. PMID:27672578

  17. Incidental finding of elongated ventral duct in a case of pancreatic divisum mimicking double pancreatic ducts on magnetic resonance cholangiopancreaticography—a rare normal variant

    PubMed Central

    Rani, Y. Jyotsna

    2015-01-01

    Anatomic variations and developmental anomalies of the pancreas and pancreatic duct are often noticed as an incidental finding on imaging. However, knowledge of these variants may prove to be crucial during surgery as it may prevent unintentional ductal injury. We report a case of pancreatic divisum with codominant ventral duct mimicking double pancreatic ducts along with the elongated uncinate process of pancreas. It was picked incidentally on magnetic resonance cholangiopancreaticography (MRCP) done to rule out cholelithiasis and choledocholithiasis. It is a rare anatomic variant and to the best of our knowledge has not been reported so far. PMID:26682149

  18. Can Analgesic-abuse Nephropathy is a Fertile Groundfor for Rare Collecting Duct (Bellini Duct) Renal Cell Carcinoma or Merely a Coincidence?

    PubMed Central

    Jhorawat, R.; Beniwal, P.; Malhotra, V.

    2016-01-01

    Nonsteroid antiinflammatory drugs have been implicated as nephrotoxic drugs, causing both acute and chronic adverse effects that range from reversible ischemia to chronic kidney disease and urothelial tumors to renal cell carcinoma specially papillary subtype. We report one case of collecting duct (Bellini duct) renal cell carcinoma in patient with analgesic-abuse nephropathy. This young individual was suffering from ankylosing spondylitis since the age of 16 years and was consuming diclofenac and paracetamol (acetaminophen) combination for >15 years. He developed hypertension, secondary glomerulopathy, chronic kidney disease and collecting duct renal cell carcinoma. PMID:27168695

  19. Comprehensive Immunophenotypic Characterization of Adult and Fetal Testes, the Excretory Duct System, and Testicular and Epididymal Appendages.

    PubMed

    Magers, Martin J; Udager, Aaron M; Chinnaiyan, Arul M; French, Diana; Myers, Jeffrey L; Jentzen, Jeffrey M; McHugh, Jonathan B; Heider, Amer; Mehra, Rohit

    2016-08-01

    The immunophenotype of a normal testis and the excretory duct system has not been studied comprehensively in fetal and adult patients without testicular disease or hormonal manipulation so far. In addition, testicular (TA) and epididymal (EA) appendages are frequent paratesticular structures without previously reported comprehensive immunophenotypic studies. Immunohistochemistry for multiple markers, including the androgen receptor (AR), the estrogen receptor (ER), the progesterone receptor (PR), the prostate-specific antigen, the prostate-specific membrane antigen, PAX8, WT1, calretinin, CK7, CK20, OCT4, SALL4, and CD117, was performed on full sections of testicular/paratesticular tissue from a large cohort of adult and fetal autopsy patients. In contrast to adult germ cells (GC), fetal GC strongly express OCT4 and CD117, although the expression of these proteins is lost in the early postnatal period; SALL4, in contrast, is expressed in both fetal and adult GC, with only weak and focal expression in adult patients. Fetal Sertoli cells (SC) express WT1 and calretinin strongly and diffusely, in contrast to adult SC. Both fetal and adult excretory duct systems express CK7 and PAX8 with frequent AR coexpression, and all 3 main segments of the excretory duct system (ductuli efferentes, epididymis, and vas deferens) have unique immunophenotypes. The rete testis also has a unique immunohistochemical expression pattern, which includes strong expression of CK7, PAX8, WT1, calretinin, and AR. Finally, of the adult autopsy patients examined, 80% had a TA, and 60% had an EA; these paratesticular structures occurred at stereotypical locations, demonstrated reproducible morphologic features, and had a unique immunophenotype relative to other studied structures, with strong CK7, PAX8, WT1, AR, ER, and PR coexpression. The testis and the paratestis may be involved by diverse neoplastic and non-neoplastic processes, and knowledge of the immunophenotypic expression spectrum of

  20. Experimental investigation of crossflow jet mixing in a rectangular duct

    NASA Technical Reports Server (NTRS)

    Liscinsky, D. S.; True, B.; Holdeman, J. D.

    1993-01-01

    An experimental investigation of the mixing of nonreacting opposed rows of jets injected normal to a confined rectangular crossflow has been conducted. Planar Mie-scattering was used to measure the time-average concentration distribution of the jet fluid in planes perpendicular to the duct axis. The mixing effectiveness of round orifice injectors was measured as a function of orifice spacing and orifice diameter. Mixing effectiveness was determined using a spatial unmixedness parameter based on the variance of mean jet concentration distributions. Optimum mixing was obtained when the spacing-to-duct height ratio was inversely proportional to the square root of the jet-to-mainstream momentum-flux ratio. For opposed rows of round holes with centerlines inline, mixing was similar for blockages up to 75 percent. Lower levels of unmixedness were obtained as a function of downstream location when axial injection length was minimized. Mixing may be enhanced if orifice centerlines of opposed rows are staggered, but note that blockage must be less than 50 percent for this configuration.