Sample records for stresses ducts pipes

  1. Reynolds-stress model prediction of 3-D duct flows

    Gerolymos, G A


    The paper examines the impact of different modelling choices in second-moment closures by assessing model performance in predicting 3-D duct flows. The test-cases (developing flow in a square duct [Gessner F.B., Emery A.F.: {\\em ASME J. Fluids Eng.} {\\bf 103} (1981) 445--455], circular-to-rectangular transition-duct [Davis D.O., Gessner F.B.: {\\em AIAA J.} {\\bf 30} (1992) 367--375], and \\tsn{S}-duct with large separation [Wellborn S.R., Reichert B.A., Okiishi T.H.: {\\em J. Prop. Power} {\\bf 10} (1994) 668--675]) include progressively more complex strains. Comparison of experimental data with selected 7-equation models (6 Reynolds-stress-transport and 1 scale-determining equations), which differ in the closure of the velocity/pressure-gradient tensor $\\Pi_{ij}$, suggests that rapid redistribution controls separation and secondary-flow prediction, whereas, inclusion of pressure-diffusion modelling improves reattachment and relaxation behaviour.

  2. The Interlayer Stress Analysis of Polyethylene-steel Composite Pipes

    WEI Xu-guang


    Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions, but the pipe may lose effectiveness in the process of transporting hot and cold media, so the research of stress distribution and variation in polyethylene-steel composite pipes is very necessary.This article first assume that a thin adhesive layer is in between the polyethylene and steel, the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off sticky.Secondly, we use a method of finite element to computer simulation by ANSYS, and verify initial assumptions. Finally, based on simulation data, we analyse the adhesive layer stress distribution and the variation with different parameters to change.Through the above research, preliminarily summarize the variation and distribution of interlaminar stress, and provide technical support for future design and process improvement of polyethylenesteel pipe.

  3. Piping Stress Analysis of Secondary Cooling Water System in CARR


    Some piping valves of China Advanced Research Reactor (CARR) cannot maintain the leak tightness when debugging. Because the valves need to be exchanged, the stress analysis and evaluation should be made for the piping with new valves in order to make sure whether

  4. Development of residual stress prediction model in pipe weldment

    Eom, Yun Yong; Lim, Se Young; Choi, Kang Hyeuk; Cho, Young Sam; Lim, Jae Hyuk [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)


    When Leak Before Break(LBB) concepts is applied to high energy piping of nuclear power plants, residual weld stresses is a important variable. The main purpose of his research is to develop the numerical model which can predict residual weld stresses. Firstly, basic theories were described which need to numerical analysis of welding parts. Before the analysis of pipe, welding of a flat plate was analyzed and compared. Appling the data of used pipes, thermal/mechanical analysis were accomplished and computed temperature gradient and residual stress distribution. For thermal analysis, proper heat flux was regarded as the heat source and convection/radiation heat transfer were considered at surfaces. The residual stresses were counted from the computed temperature gradient and they were compared and verified with a result of another research.

  5. Stresses Analysis of Petroleum Pipe Finite Element under Internal Pressure



    Full Text Available This paper described the results of a nonlinear static mode within ANSYS of elastic and elastic-plastic behaviour of thin petroleum pipe that is subjected to an internal pressure and therefore a linear stress analysis performed using ANSYS 9.0 finite element software Such an analysis is important because the shape of most structures under internal pressure is cylindrical[1]. In this paper is considered only. Elastic and elastic-plastic finite element analysis is used to predict the principle stresses, effective stress results are compared with those obtained from theatrical equations in order to predict the limit and failure loads for this type of loading also the relationships between redial, hoop stresses and displacement has been used to develop a through understanding. The analysis was completed using ANAYS Version 9.0. (a finite element program for Microsoft Windows NT. The program allows pre-processing, analysis and post-processing stages to be completed within a single application. The program can be used to model a large number of situations including buckling, plastic deformation, forming and stress analysis problems. r mm (In this study ,a thin pipe of internal radiu ri 596 .9 mmand of externalo 609 .6objected to aninternal pressure 2 i  4 .83  / mm which is gradually increased to near the ultimate load that may be sustained by the pipe. The pipe is modelled as an elasto-plastic material using the Von Mises yield criterion which is normally used for metallic materials[2]. The specification of the load in several increments enables the spread of the plasticity to occur gradually and its effect on the stress distribution to be assessed. Key words: finite element analysis, elastic-plastic behavior, thin walled pipe equivalent stress, TWT.

  6. Analysis of the coherent and turbulent stresses of a numerically simulated rough wall pipe

    Chan, L.; MacDonald, M.; Chung, D.; Hutchins, N.; Ooi, A.


    A turbulent rough wall flow in a pipe is simulated using direct numerical simulation (DNS) where the roughness elements consist of explicitly gridded three-dimensional sinusoids. Two groups of simulations were conducted where the roughness semi-amplitude h+ and the roughness wavelength λ+ are systematically varied. The triple decomposition is applied to the velocity to separate the coherent and turbulent components. The coherent or dispersive component arises due to the roughness and depends on the topological features of the surface. The turbulent stress on the other hand, scales with the friction Reynolds number. For the case with the largest roughness wavelength, large secondary flows are observed which are similar to that of duct flows. The occurrence of these large secondary flows is due to the spanwise heterogeneity of the roughness which has a spacing approximately equal to the boundary layer thickness δ.

  7. Stimulated bioluminescence by fluid shear stress associated with pipe flow

    Cao Jing; Wang Jiangan; Wu Ronghua, E-mail: [Col. of Electronic Eng., Naval University of Engineering, Wuhan 430033 (China)


    Dinoflagellate can be stimulated bioluminescence by hydrodynamic agitation. Two typical dinoflagellate (Lingulodinium polyedrum and Pyrocystis noctiluca) was choosed to research stimulated bioluminescence. The bioluminescence intensity and shear stress intensity were measured using fully developed pipe flow. There is shear stress threshold to agitate organism bioluminescence. From these experiment, the response thresholds of the stimulated bioluminscence always occurred in laminar flows at a shear stress level of 0.6-3 dyn/cm{sup 2}. At the same time, the spectral characteristc of dinoflagellate was recorded, the wavelength of them is about 470nm, and the full width at half maximum is approximate 30nm.

  8. Sensitivity studies of heat transfer: forced convection across a cylindrical pipe and duct flow

    Ferrantelli, Andrea; Viljanen, Martti


    We consider two common heat transfer processes and perform a through sensitivity study of the variables involved. We derive and discuss analytical formulas for the heat transfer coefficient in function of film velocity, air temperature and pipe diameter. The according plots relate to a qualitative analysis of the multi-variable function $h$, according to functional optimization. For each process, we provide with graphs and tables of the parameters of interest, such as the Reynolds number. This method of study and the specific values can constitute a useful reference for didactic purposes.

  9. Stress-Stain State of Pipe Made of Copper-Based Alloy Strengthened with Incoherent Nanoparticles

    Matvienko, O. V.; Daneyko, O. I.; Kovalevskaya, T. A.


    The approach which combines methods of crystal plasticity and deformable solid mechanics is used to explore the stress-strain state of a heavy-wall pipe made of dispersion-hardened Cu-based alloy and subjected to the uniform internal pressure. The distribution of the deformation and stress along the pipe wall is determined for various pipe geometry. The approximating equations are obtained to determine the yielding area and elastic and plastic strength limits.

  10. 49 CFR Appendix C to Part 192 - Qualification of Welders for Low Stress Level Pipe


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Qualification of Welders for Low Stress Level Pipe.... C Appendix C to Part 192—Qualification of Welders for Low Stress Level Pipe I. Basic test. The test... position welding. The beveling, root opening, and other details must conform to the specifications of...

  11. Axial stress localization facilitates pressure propagation in gelled pipes

    Norrman, Jens; Skjæraasen, Olaf; Oschmann, Hans-Jörg; Paso, Kristofer; Sjöblom, Johan


    Paraffin wax-oil gels are unique rheological fluids which undergo shear degradation starting at a deformation (shear strain level) of approximately 1%. Flow commencement in pipelines filled with wax-oil gels is a complex hydrodynamic process involving propagation of acoustic, diffusive, and rheological degradation pressure wave fronts. Dynamic simulation informed by qualified rheological relations provides useful insight into the physical nature of these flow processes. Eulerian simulations are presented which emulate known physical phenomena and essential characteristics of wax-gel flow dynamics. A constitutive rheological equation set accounts for deformation-driven reduction in yield stress and viscosity terms. No explicit time-dependent rheological parameters are utilized in the equations. Rheological yielding alters the nature of the dominant pressure wave from inherently diffusive towards self-sharpening. Axial stress localization effectively sequentializes the gel breakage process, quantified by reduced length of the pressure wave-front zone. Ultimately, axial stress localization allows flow in longer pipe segments, albeit with a concomitant time delay. Viscous behavior and yielding degradation behavior are shown to account for upward and downward concavity in transient axial pressure profiles, respectively. Overall, a unique synergy between gel compressibility and gel degradation is revealed. Deformation-coupled interaction between compressibility and degradation allows pressure propagation and subsequent sustained flow through a gel material which is otherwise immobile in the incompressible case.

  12. Modeling of residual stress mitigation in austenitic stainless steel pipe girth weldment

    Li, M.; Atteridge, D.G.; Anderson, W.E. [Oregon Graduate Inst., Portland, OR (United States); West, S.L. [Westinghouse Savannah River Co., Aiken, SC (United States)


    This study provides numerical procedures to model 40-cm-diameter, schedule 40, Type 304L stainless steel pipe girth welding and a newly proposed post-weld treatment. The treatment can be used to accomplish the goal of imparting compressive residual stresses at the inner surface of a pipe girth weldment to prevent/retard the intergranular stress corrosion cracking (IGSCC) of the piping system in nuclear reactors. This new post-weld treatment for mitigating residual stresses is cooling stress improvement (CSI). The concept of CSI is to establish and maintain a certain temperature gradient across the pipe wall thickness to change the final stress state. Thus, this process involves sub-zero low temperature cooling of the inner pipe surface of a completed girth weldment, while simultaneously keeping the outer pipe surface at a slightly elevated temperature with the help of a certain heating method. Analyses to obtain quantitative results on pipe girth welding and CSI by using a thermo-elastic-plastic finite element model are described in this paper. Results demonstrate the potential effectiveness of CSI for introducing compressive residual stresses to prevent/retard IGSCC. Because of the symmetric nature of CSI, it shows great potential for industrial application.

  13. Residual stress state in pipe cut ring specimens for fracture toughness testing

    Damjanovic, Darko [J.J. Strossmayer Univ. of Osijek, Slavonski Brod (Croatia). Mechanical Engineering Faculty; Kozak, Drazan [Zagreb Univ. (Croatia). Dept. for Mechanical Design; Marsoner, Stefan [Materials Center, Leoben (Austria).; Gubeljak, Nenad [Maribor Univ. (Slovenia). Chair of Mechanics


    Thin-walled pipes are not suitable for measuring fracture toughness parameters of vital importance because longitudinal crack failure is the most common failure mode in pipes. This is due to the impossibility to manufacture standard specimens for measuring fracture toughness, such as SENB or CT specimens, from the thin wall of the pipe. Previous works noticed this problem, but until now, a good and convenient solution has not been found or developed. To overcome this problem, very good alternative solution was proposed, the so-called pipe ring notched bend specimen (PRNB) [1-5]. Until now, only the idealized geometry PRNB specimen is analyzed, i. e., a specimen which is not cut out from an actual pipe but produced from steel plate. Based on that, residual stresses are neglected along with the imperfections in geometry (elliptical and eccentricity). The aim of this research is to estimate the residual stress state(s) in real pipes used in the boiler industry produced by hot rolling technique. These types of pipes are delivered only in normalized condition, but not stress relieved. Therefore, there are residual stresses present due to the manufacturing technique, but also due to uneven cooling after the production process. Within this paper, residual stresses are estimated by three methods: the incremental hole drilling method (IHMD), X-ray diffraction (XRD) and the splitting method (SM). Knowing the residual stress state in the ring specimen, it is possible to assess their impact on fracture toughness measured on the corresponding PRNB specimen(s).

  14. A Method Using Optical Contactless Displacement Sensors to Measure Vibration Stress of Small-Bore Piping.

    Maekawa, Akira; Tsuji, Takashi; Takahashi, Tsuneo; Noda, Michiyasu


    In nuclear power plants, vibration stress of piping is frequently evaluated to prevent fatigue failure. A simple and fast measurement method is attractive to evaluate many piping systems efficiently. In this study, a method to measure the vibration stress using optical contactless displacement sensors was proposed, the prototype instrument was developed, and the instrument practicality for the method was verified. In the proposed method, light emitting diodes (LEDs) were used as measurement sensors and the vibration stress was estimated by measuring the deformation geometry of the piping caused by oscillation, which was measured as the piping curvature radius. The method provided fast and simple vibration estimates for small-bore piping. Its verification and practicality were confirmed by vibration tests using a test pipe and mock-up piping. The stress measured by both the proposed method and an accurate conventional method using strain gauges were in agreement, and it was concluded that the proposed method could be used for actual plant piping systems.

  15. Stress analysis of the O-element pipe during the process of flue gases purification

    Nekvasil R.


    Full Text Available Equipment for flue gases purification from undesired substances is used throughout power and other types of industry. This paper deals with damaging of the O-element pipe designed to remove sulphur from the flue gases, i.e. damaging of the pipe during flue gases purification. This purification is conducted by spraying the water into the O-shaped pipe where the flue gases flow. Thus the sulphur binds itself onto the water and gets removed from the flue gas. Injection of cold water into hot flue gases, however, causes high stress on the inside of the pipe, which can gradually damage the O-element pipe. In this paper initial injection of water into hot pipe all the way to stabilization of temperature fields will be analyzed and the most dangerous places which shall be considered for fatigue will be determined.

  16. Background of SIFs and Stress Indices for Moment Loadings of Piping Components

    E. A. Wais; E. C. Rodabaugh


    This report provides background information, references, and equations for twenty-four piping components (thirteen component SIFs and eleven component stress indices) that justify the values or expressions for the SIFs and indices.

  17. Stress Analysis of the Subsea Dynamic Riser BaseProcess Piping

    Xuanze Ju; Wei Fang; Hanjun Yin; Ying Jiang


    Thesubsea dynamic riser base(SDRB)is an important piece of equipment for the floating production platform mooring system.One end is connected to the rigid pipeline, carrying a rigid pipeline thermal expansion load and the other end is connected to a flexible riser, carrying the dynamic load of the flexible riser, so its function is a transition connection between the flexible riser and the rigid pipeline which fixes the flexible riser on the seabed. On the other hand , as a typical subsea product, the design will satisfythe requirements of the standards for subsea products. By studying the stress analysisphilosophy of the topside piping and subsea pipeline, a physical model and procedure for piping stress analysis of the SDRB have been established.The conditions of the adverse design load have been considered, and a combination of the static load from the rigid pipeline and the dynamic load flexibility has also been optimized. And a comparative analysis between the AMSE, DNV and API standards for piping stress with the checking rules has been done.Because theSDRB belongs to the subsea pipeline terminal product, the use of DNV standards to check its process piping stress is recommended. Finally, the process piping stress of the SDRB has been calculated, and the results show that the jacket pipe and the carrier pipe stress of the SDRB process piping satisfy the DNV standards as a whole.The bulkhead cannot be accurately simulated by the AutoPIPE software which uses the FEA software ANSYS inthe detailed analysis, but the checking results will still meet the requirements of the DNV standards.

  18. Pipe stress analysis on HCCR-TBS ancillary systems in conceptual design

    Ahn, Mu-Young, E-mail: [National Fusion Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of); Lee, Eo Hwak [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi-Hyun; Lee, Youngmin [National Fusion Research Institute, Daejeon (Korea, Republic of)


    Highlights: • Pipe stress is performed on Korean HCCR-TBS for the load combinations including seismic events. • The resultant stress meets the requirement of the design code & standard except one position where modification is needed. • The results gives useful information for the design evolution in the next desgin phase. - Abstract: Korean Helium Cooled Ceramic Reflector (HCCR) Test Blanket System (TBS) will be tested in ITER to demonstrate feasibility of the breeding blanket concept. The HCCR-TBS comprises Test Blanket Module (TBM) with associated shield, and ancillary systems located in various positions of ITER building. Currently, conceptual design for the HCCR-TBS is in progress. This paper presents pipe stress analysis results for the HCCR-TBS ancillary systems. The pipe stress analysis was performed in accordance with ASME B31.3 for major pipes of the Helium Cooling System (HCS) and the Coolant Purification System (CPS), which are operated in high pressure and temperature. The pipe stress for various load cases and load combinations were calculated. Operational pressure and temperature during plasma operation are applied as pressure load and thermal load, respectively. In addition seismic events were combined to investigate the code compliance for sustained load case and occasional load case. It was confirmed that the resultant stress meets the requirements of ASME B31.3 except one position in which it needs modification. These results give useful information for the next design phase, for example, nozzle loads for the component selection, the support design parameters, etc.

  19. Heat sink welding of austenitic stainless steel pipes to control distortion and residual stress

    Kumar, H.; Albert, S.K.; Bhaduri, A.K. [Materials Technology Div., Indira Gandhi Centre for Atomic Research, Kalpakkam (India)


    Construction of India's Prototype Fast Breeder Reactor (PFBR) involves extensive welding of austenitic stainless steels pipes of different dimensions. Due to high thermal expansion coefficient and poor thermal conductivity of this class of steels, welding can result in significant distortion of these pipes. Attempts to arrest this distortion can lead to high levels of residual stresses in the welded parts. Heat sink welding is one of the techniques often employed to minimize distortion and residual stress in austenitic stainless steel pipe welding. This technique has also been employed to repair welding of the piping of the Boiling Water Reactors (BWRs) subjected to radiation induced intergranular stress corrosion cracking (IGSCC). In the present study, a comparison of the distortion in two pipe welds, one made with heat sink welding and another a normal welds. Pipes of dimensions 350{phi} x 250(L) x 8(t) mm was fabricated from 316LN plates of dimensions 1100 x 250 x 8 mm by bending and long seam (L-seam) welding by SMAW process. Two fit ups with a root gap of 2 mm, land height of 1mm and a groove angle of 70 were prepared using these pipes for circumferential seam (C-seam) welding. Dimensions at predetermined points in the fit up were made before and after welding to check the variation in radius, circumference and and ovality of the pipes. Root pass for both the pipe fit up were carried out using conventional GTAW process with 1.6 mm AWS ER 16-8-2 as consumables. Welding of one of the pipe fit ups were completed using conventions GTAW process while the other was completed using heat sink welding. For second and subsequent layers of welding using this process, water was sprayed at the root side of the joint while welding was in progress. Flow rate of the water was {proportional_to}6 1/minute. Welding parameters employed were same as those used for the other pipe weld. Results of the dimensional measurements showed that there is no circumferential shrinkage in

  20. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    Kim, Kang Soo; Lee, Ho Jin; Woo, Wan Chuck; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo; Jung, In Chul [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)


    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  1. The Effect of Welding Residual Stress for Making Artificial Stress Corrosion Crack in the STS 304 Pipe

    Jae-Seong Kim


    Full Text Available The stress corrosion crack is one of the fracture phenomena for the major structure components in nuclear power plant. During the operation of a power plant, stress corrosion cracks are initiated and grown especially in dissimilar weldment of primary loop components. In particular, stress corrosion crack usually occurs when the following three factors exist at the same time: susceptible material, corrosive environment, and tensile stress (residual stress included. Thus, residual stress becomes a critical factor for stress corrosion crack when it is difficult to improve the material corrosivity of the components and their environment under operating conditions. In this study, stress corrosion cracks were artificially produced on STS 304 pipe itself by control of welding residual stress. We used the instrumented indentation technique and 3D FEM analysis (using ANSYS 12 to evaluate the residual stress values in the GTAW area. We used the custom-made device for fabricating the stress corrosion crack in the inner STS 304 pipe wall. As the result of both FEM analysis and experiment, the stress corrosion crack was quickly generated and could be reproduced, and it could be controlled by welding residual stress.

  2. Stability of cracked pipe under inertial stresses. Subtask 1.1 final report

    Scott, P.; Wilson, M.; Olson, R.; Marschall, C.; Schmidt, R.; Wilkowski, G. [Battelle, Columbus, OH (United States)


    This report presents the results of the pipe fracture experiments, analyses, and material characterization efforts performed within Subtask 1.1 of the IPIRG Program. The objective of Subtask 1.1 was to experimentally verify the analysis methodologies for circumferentially cracked pipe subjected primarily to inertial stresses. Eight cracked-pipe experiments were conducted on 6-inch nominal diameter TP304 and A106B pipe. The experimental procedure was developed using nonlinear time-history finite element analyses which included the nonlinear behavior due to the crack. The model did an excellent job of predicting the displacements, forces, and times to maximum moment. The comparison of the experimental loads to the predicted loads by the Net-Section-Collapse (NSC), Dimensionless Plastic-Zone Parameter, J-estimation schemes, R6, and ASME Section XI in-service flaw assessment criteria tended to underpredict the measured bending moments except for the NSC analysis of the A106B pipe. The effects of flaw geometry and loading history on toughness were evaluated by calculating the toughness from the pipe tests and comparing these results to C(l) values. These effects were found to be variable. The surface-crack geometry tended to increase the toughness (relative to CM results), whereas a negative load-ratio significantly decreased the TP304 stainless steel surface-cracked pipe apparent toughness. The inertial experiments tended to achieve complete failure within a few cycles after reaching maximum load in these relatively small diameter pipe experiments. Hence, a load-controlled fracture mechanics analysis may be more appropriate than a displacement-controlled analysis for these tests.

  3. Allowable Stresses For Use in Dynamic Analysis of PF-4 Fire Suppression System Piping

    Menefee, Maia Catherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Salmon, Michael W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The purpose of this paper is to present the results of a limited test program performed on samples of fittings removed from the PF-4 fire suppression system and to present recommendations for allowable stresses to be used in subsequent piping analysis.

  4. Round robin analysis on stress intensity factor of inner surface cracks in welded stainless steel pipes

    Han, Chang Gi; Chang, Yoon Suk [Dept. of Nuclear Engineering, College of Engineering, Kyung Hee University, Yongin (Korea, Republic of); Kim, Jong Sung [Dept. of Mechanical Engineering, Sunchon National University, Sunchon (Korea, Republic of); Kim, Maan Won [Central Research Institute, Korea Hydro and Nuclear Power Company, Daejeon (Korea, Republic of)


    Austenitic stainless steels (ASSs) are widely used for nuclear pipes as they exhibit a good combination of mechanical properties and corrosion resistance. However, high tensile residual stresses may occur in ASS welds because postweld heat treatment is not generally conducted in order to avoid sensitization, which causes a stress corrosion crack. In this study, round robin analyses on stress intensity factors (SIFs) were carried out to examine the appropriateness of structural integrity assessment methods for ASS pipe welds with two types of circumferential cracks. Typical stress profiles were generated from finite element analyses by considering residual stresses and normal operating conditions. Then, SIFs of cracked ASS pipes were determined by analytical equations represented in fitness-for-service assessment codes as well as reference finite element analyses. The discrepancies of estimated SIFs among round robin participants were confirmed due to different assessment procedures and relevant considerations, as well as the mistakes of participants. The effects of uncertainty factors on SIFs were deducted from sensitivity analyses and, based on the similarity and conservatism compared with detailed finite element analysis results, the R6 code, taking into account the applied internal pressure and combination of stress components, was recommended as the optimum procedure for SIF estimation.

  5. Round Robin Analyses on Stress Intensity Factors of Inner Surface Cracks in Welded Stainless Steel Pipes

    Chang-Gi Han


    Full Text Available Austenitic stainless steels (ASSs are widely used for nuclear pipes as they exhibit a good combination of mechanical properties and corrosion resistance. However, high tensile residual stresses may occur in ASS welds because postweld heat treatment is not generally conducted in order to avoid sensitization, which causes a stress corrosion crack. In this study, round robin analyses on stress intensity factors (SIFs were carried out to examine the appropriateness of structural integrity assessment methods for ASS pipe welds with two types of circumferential cracks. Typical stress profiles were generated from finite element analyses by considering residual stresses and normal operating conditions. Then, SIFs of cracked ASS pipes were determined by analytical equations represented in fitness-for-service assessment codes as well as reference finite element analyses. The discrepancies of estimated SIFs among round robin participants were confirmed due to different assessment procedures and relevant considerations, as well as the mistakes of participants. The effects of uncertainty factors on SIFs were deducted from sensitivity analyses and, based on the similarity and conservatism compared with detailed finite element analysis results, the R6 code, taking into account the applied internal pressure and combination of stress components, was recommended as the optimum procedure for SIF estimation.

  6. Prediction of Welding Residual Stress in 2. 25Cr-1Mo Steel Pipe


    A numerical analysis method was proposed to predict the welding residual stress in 2.25Cr-1Mo steel pipe considering solid-state phase transformations. A thermal elastic plastic finite element (FE) model considering effects of martensite transformation was developed based on commercial ABAQUS software. Continuous cooling transformation (CCT) diagrams were employed to simulate the fraction of martensite in fusion zone, coarsegrained heat affected zone and fine-grained heat affected zone. The Koistinen-Marburger relationship was used to trace the formation of martensite. The effects of both volume change and yield strength change due to phase transformation on welding residual stress were considered using the proposed FE model. The result shows that the phase transformation has significant effects on the welding residual stress in multi-pass butt weld of pipe. The predicted simulation results by the proposed numerical method are generally in good agreement with experimental results.

  7. Using the stress function in the flow of generalized Newtonian fluids through pipes and slits

    Sochi, Taha


    We use a generic and general numerical method to obtain solutions for the flow of generalized Newtonian fluids through circular pipes and plane slits. The method, which is simple and robust can produce highly accurate solutions which virtually match any analytical solutions. The method is based on employing the stress, as a function of the pipe radius or slit thickness dimension, combined with the rate of strain function as represented by the fluid rheological constitutive relation that correlates the rate of strain to stress. Nine types of generalized Newtonian fluids are tested in this investigation and the solutions obtained from the generic method are compared to the analytical solutions which are obtained from the Weissenberg-Rabinowitsch-Mooney-Schofield method. Very good agreement was obtained in all the investigated cases. All the required quantities of the flow which include local viscosity, rate of strain, flow velocity profile and volumetric flow rate, as well as shear stress, can be obtained from ...

  8. Residual stress determination in a dissimilar weld overlay pipe by neutron diffraction

    Woo, Wanchuck, E-mail: [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Em, Vyacheslav [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Hubbard, Camden R. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Lee, Ho-Jin [Nuclear Materials Research Center, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Park, Kwang Soo [Corporate R and D Institute, Doosan Heavy Industries and Construction, Changwon 641-792 (Korea, Republic of)


    Highlights: {yields} Determined residual stress distribution in a dissimilar weld overlay pipe. {yields} Consists of a ferritic (SA508), austenitic (F316L) steels, Alloy 182 consumable. {yields} Measured significant compression (-600 MPa) near the inner wall of overlay. {yields} Validate integrity of the inner wall for the pressurized nozzle nuclear structure. - Abstract: Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic 'stress-free' lattice spacing (d{sub o}) was also obtained from both using a 2-mm width comb-like coupon. The results show significant changes in residual stresses from tension (300-400 MPa) to compression (-600 MPa) through the thickness of the dissimilar weld overlay pipe specimen.

  9. Hydrogen-related stress corrosion cracking in line pipe steel

    Nielsen, Lars Vendelbo


    A correlation between hydrogen concentration (C0) and the critical stress intensity factor for propagation of hydrogen-related cracks has been established by fracture mechanical testing of CT-specimens for the heat affected zone of an X-70 pipeline steel. This has been compared with field...

  10. Investigation and Analysis of Weld Induced Residual Stresses in Two Dissimilar Pipes by Finite Element Modeling

    Nadimi, S.; Khoushehmehr, R. J.; Rohani, B.; Mostafapour, A.

    In the present study, Manual Metal Arc Welding (MMAW) of austenitic stainless steel to carbon steel were studied. The Schaeffler diagram were used in determining suitable filler metal for this process and then the finite element analysis of residual stresses in butt welding of two dissimilar pipes is performed with the commercial software ANSYS, which includes moving heat source, material deposit, temperature dependant material properties, metal plasticity and elasticity, transient heat transfer and mechanical analysis. The residual stresses distribution and magnitude in the hoop and axial directions in the inner and outer surfaces of two dissimilar pipes were obtained. Welding simulation considered as a sequentially coupled thermo-mechanical analysis and the element birth and death technique was employed for simulation of filler metal deposition.

  11. Numerical predictions and measurements of Reynolds normal stresses in turbulent pipe flow of polymers

    Resende, P.R. [Centro de Estudos de Fenomenos de Transporte, DEMEGI, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto (Portugal)]. E-mail:; Escudier, M.P. [Department of Engineering, University of Liverpool, Brownlow Street, Liverpool L69 3GH (United Kingdom)]. E-mail:; Presti, F [Department of Engineering, University of Liverpool, Brownlow Street, Liverpool L69 3GH (United Kingdom); Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, DEM, Universidade do Minho Campus de Azurem, 4800-058 Guimaraes (Portugal)]. E-mail:; Cruz, D.O.A. [Departamento de Engenharia Mecanica, Universidade Federal do Para-UFPa Campus Universitario do Guama, 66075-900 Belem, Para (Brazil)]. E-mail:


    An anisotropic low Reynolds number k-{epsilon} turbulence model has been developed and its performance compared with experimental data for fully-developed turbulent pipe flow of four different polymer solutions. Although the predictions of friction factor, mean velocity and turbulent kinetic energy show only slight improvements over those of a previous isotropic model [Cruz, D.O.A., Pinho, F.T., Resende, P.R., 2004. Modeling the new stress for improved drag reduction predictions of viscoelastic pipe flow. J. Non-Newt. Fluid Mech. 121, 127-141], the new turbulence model is capable of predicting the enhanced anisotropy of the Reynolds normal stresses that accompanies polymer drag reduction in turbulent flow.

  12. Finite Element Method Analysis of the Stress for Line Pipe with Corrode Groove During Outdoor Storage

    Zhuanzhao YANG; Daoxin LIU; Xiaohua ZHANG


    The basic principle of corrode groove on outside of steel pipe during storage was analyzed in this paper,namely the water film on the contacted surface of steel pipe,which gathered from humidity in the air,rain or gel,and the suspended particles in air,and the corrosive composition,such as SO2,CO2,O2 and NaCl,in addition to the inhomogeneity of the organization and composition,which lead to the corrosion cell reaction,so that cause the corrosion initial from the contact surface of the between steel pipes,so as to form the corrosion groove.At the same time,the corrosion groove with depth of 0.125t (t pipe wall thickness) on the pipe of φ 1016 mm×21 mm X70 API SPEC 5L was simulated using the FEM (finite element method),and the stress and strain distribution of the defect area near corrosion groove were solved at the inner pressure of 12 MPa,10 MPa,8 MPa,6 MPa,4 MPa and 2 MPa,respectively,which showed that no matter the pressure values were,the maximum stress and strain were lied at the bottom of corrosion defects groove and were in good linear relationship with the internal pressure increasing from 2 MPa to 6 MPa.When the internal pressures were greater than 6 MPa,they felled into the nonlinear model and to be yielded or even to be destroyed.In addition,the residual strength and the limit operation pressure of the corrode pipe with the defects groove of 0.125t were calculated or simulated according to the theoretical calculation,the finite element method based on the stress,the finite element method based on strain,DNV-RP-F101,ASME B31G and experimental methods respectively.The results showed that the residual strength and the limit operation pressure of the defective parts solved by the finite element method based on stress were 424 MPa,and 15.34 MPa,respectively,which was very close to that of experimental method,the residual strength was 410 MPa and the limit operation pressure 14.78 MPa.Besides,the results also showed that it was feasible and effective to

  13. Effects of dexamethasone on small bowel and kidney oxidative stress and histological alterations in bile duct-ligated rats.

    Ozturk, Hayrettin; Eken, Halil; Ozturk, Hulya; Buyukbayram, Huseyin


    Oxidative stress plays an important role in the pathogenesis of toxic liver diseases and other hepatic alterations including obstruction of bile flow. It has been shown that the gastrointestinal tract and renal tissue is particularly affected during obstruction of bile flow. In this study, we aimed to evaluate the effects of dexamethasone on small bowel and kidney oxidative stress and histological alterations in bile duct-ligated (BDL) rats. A total of 40 male Sprague-Dawley rats weighing 200-240 g were used in this study. Group 1 (Sham-control, n = 10) rats underwent laparotomy and bile duct was dissected from the surrounding tissue. Group 2 (Dexa-control, n = 10) rats underwent laparotomy and bile duct was dissected from the surrounding tissue. The rats received daily dexamethasone. Group 3 (BDL/Untreated, n = 10) rats were subjected to bile duct ligation and no drug was applied. Group 4 (BDL/Dexa, n = 10) rats received daily dexamethasone by orogastric tube for 14 days after BDL. At the end of the 2-week period, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured and biochemical and histological evaluation were processed. The mean serum bilirubin, liver enzymes, MDA level, and histopathological score significantly decreased and SOD, CAT, and GSH-Px values were significantly increased in group 4 when compared to group 3. Group 3 presented a significant increase in caecal count of E. coli and in aerobe/anaerobe ratio. In group 4, liver was moderately damaged. Ileal biopsies from group 4 demonstrated a significant increase in villus height, total mucosal thickness, and villus density when compared to group 3. Glomerular injury scores (GIS) and arterial injury scores (AIS) in group 3 rats were increased in the juxtamedullary region. In contrast to group 4, tubulo-interstitial lesions were diffuse in group 3 animals. Dexamethasone reduced small bowel and kidney oxidative stress and histological

  14. Report of the US Nuclear Regulatory Commission Piping Review Committee. Volume 1. Investigation and evaluation of stress corrosion cracking in piping of boiling water reactor plants


    IGSCC in BWR piping is occurring owing to a combination of material, environment, and stress factors, each of which can affect both the initiation of a stress-corrosion crack and the rate of its subsequent propagation. In evaluating long-term solutions to the problem, one needs to consider the effects of each of the proposed remedial actions. Mitigating actions to control IGSCC in BWR piping must be designed to alleviate one or more of the three synergistic factors: sensitized material, the convention BWR environment, and high tensile stresses. Because mitigating actions addressing each of these factors may not be fully effective under all anticipated operating conditions, mitigating actions should address two and preferably all three of the causative factors; e.g., material plus some control of water chemistry, or stress reversal plus controlled water chemistry.

  15. Through-Thickness Measurements of Residual Stresses in an Overlay Dissimilar Weld Pipe using Neutron Diffraction

    Woo, Wan Chuck; EM, Vyacheslav; Lee, Ho Jin; Kim, Kang Soo; Kang, Mi Hyun; Joo, Jong Dae; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)


    The distribution of residual stresses in dissimilar material joints has been extensively studied because of the wide applications of the dissimilar welds in many inevitable complex design structures. Especially the cracking of dissimilar welding has been a long standing issue of importance in many components of the power generation industries such as nuclear power plant, boiling pressure system, and steam generators. In particular, several failure analysis and direct observations have shown that critical fractures have frequently occurred in one side of the dissimilar welded parts. For example, the heat-affected zone on the ferrite steel side is known to critical in many dissimilar welding pipes when ferrite (low carbon steel) and austenite (stainless) steels are joined. The main cause of the residual stresses can be attributed to the mismatch in the coefficient of thermal expansion between the dissimilar metals (ferrite and austenite). Additional cladding over circumferential welds is known to reinforce the mechanical property due to the beneficial compressive residual stress imposed on the weld and heat-affected zone. However, science-based quantitative measurement of the through thickness residual stress distribution is very limited in literature. The deep penetration capability of neutrons into most metallic materials makes neutron diffraction a powerful tool to investigate and map the residual stresses of materials throughout the thickness and across the weld. Furthermore, the unique volume averaged bulk characteristic of materials and mapping capability in three dimensions are suitable for the engineering purpose. Thus, the neutron-diffraction measurement method has been selected as the most useful method for the study of the residual stresses in various dissimilar metal welded structures. The purpose of this study is to measure the distribution of the residual stresses in a complex dissimilar joining with overlay in the weld pipe. Specifically, we measured

  16. Investigation of Residual Stresses and Distortion in Welded Pipe-Flange Joint of Different Classes

    Muhammad Abid


    Full Text Available ABSTRACT: Pipe and flange joints are commonly used in petrochemical, nuclear and process industries. Commonly, welding is used to make these joints which produces residual stresses and distortions. These stresses have detrimental effects on the structural integrity and service performance of the welded pipe joints. The objective of this study is to investigate the residual stresses and distortions during Gas Metal Arc Welding of pipe of schedule 40, nominal diameter 200 mm with different ANSI flanges of class numbers 150, 300, 600, 900, 1500, and 2500. Welding parameters including: voltage, current and heat as inputs were selected based on the literature available. The behaviour of the flanges of different classes is also discussed. In addition, the finite element methodology presented, in this paper, can be helpful for developing welding procedures for a range of pipe flange welded joint sizes in order to control the residual stresses and deformations. This will lead to optimised performance during bolt up and operating conditions.ABSTRAK: Paip dan sambungan flan biasanya digunakan dalam industri petrokimia, nuklear dan proses. Kimpalan menghasilkan tegasan sisa dan herotan, yang memberikan kesan yang merbahaya ke atas integriti struktur dan prestasi servis sambungan kimpalan paip. Objektif kajian ini adalah untuk mengkaji tegasan sisa dan herotan ketika kimpalan arka logam gas paip berjadual 40, diameter nominal 200mm dengan flan ANSI yang berbeza kelas # 150, 300, 600, 900, 1500, dan 2500. Parameter kimpalan termasuklah; voltan, arus dan haba input yang dipilih berdasarkan literatur sediada. Kelakuan flan yang berbeza kelas telah dibincangkan. Kaedah elemen finit yang dibentangkan adalah berguna dalam membangunkan prosedur kimpalan bagi julat saiz kimpalan flan paip unutk mengawal tegasan sisa dan canggaan i.e. bagi mengoptimakan prestasi ketika bolt up dan sedang beroperasi.                                 

  17. Effects of weld residual stresses on crack-opening area analysis of pipes for LBB applications

    Dong, P.; Rahman, S.; Wilkowski, G. [and others


    This paper summarizes four different studies undertaken to evaluate the effects of weld residual stresses on the crack-opening behavior of a circumferential through-wall crack in the center of a girth weld. The effect of weld residual stress on the crack-opening-area and leak-rate analyses of a pipe is not well understood. There are no simple analyses to account for these effects, and, therefore, they are frequently neglected. The four studies involved the following efforts: (1) Full-field thermoplastic finite element residual stress analyses of a crack in the center of a girth weld, (2) A comparison of the crack-opening displacements from a full-field thermoplastic residual stress analysis with a crack-face pressure elastic stress analysis to determine the residual stress effects on the crack-opening displacement, (3) The effects of hydrostatic testing on the residual stresses and the resulting crack-opening displacement, and (4) The effect of residual stresses on crack-opening displacement with different normal operating stresses.

  18. 胆总管取石术后T型管夹管方法的研究%Clinical research on griping T-type pipe earlg after stonermoving operation of common bile duct

    解涛; 邢金德; 刘向阳; 孙黎明; 宋吉杰


    为探讨一种胆总管取石术后减少胆汁丢失的方法,对180例行胆总管取石术、T型管引流患者给予选择性、试验性早期夹管(夹管组),并与120例不行夹管者(对照组)进行比较。结果显示,夹管组术后血液中电解质变化、每日胆汁丢失量、每日输液量等方面与对照组比较差异有显著性(P<0.01),夹管组肠功能恢复早,平均住院天数短。认为胆总管取石术后早期行T型管夹管,能减少胆汁丢失,患者下床活动早,手术愈合快。%To evaluate a method which can decrease loss of bile after commonduct jtoneremoving operation.180 patients who received common duct stone-removing T-type drainage were given selective and experimental pipe-griping to compare with those who weren’t give such pipe-griping and observed the clinical results.Results showed that the differences of the electrolyte-changing in the blood,the everyday amount of bile-losing,the everyday amount were of remarkable differance in patients who were given early pipe-griping and the control group(P<0.01).As for the pipe-griping group,the intestinal function recovered early and the average hospitalization days were short as well.This suggests that the early pipe-griping of the T-type pipe after common duct stoneremoving openation can reduce the loss of bile,make the patient convenient to move out of bed and favorable to the patient’s clinieal healing

  19. Finite Element Analysis of Modeling Residual Stress Distribution in All-position Duplex Stainless Steel Welded Pipe

    Xiaojun JIN; Lixing HUO; Yufeng ZHANG; Bingren BAI; Xiaowei LI; Jun CAO


    On the basis of the thermal-elastic-plastic theory, a three-dimensional finite element numerical simulation is performed on the girth welded residual stresses of the duplex stainless steel pipe with ANSYS nonlinear finite element program for the first time. Three-dimensional FEM using mobile heat source for analysis transient temperature field and welding stress field in circumferential joint of pipes is founded. Distributions of axial and hoop residual stresses of the joint are investigated. The axial and the hoop residual stresses at the weld and weld vicinity on inner surface of pipes are tensile, and they are gradually transferred into compressive with the increase of the departure from the weld. The axial residual stresses at the weld and weld vicinity on outer surface of pipes is compressive while the hoop one is tensile. The distributions of residual stresses compared positive-circle with negative-circle show distinct symmetry. These results provide theoretical knowledge for the optimization of process and the control of welding residual stresses.

  20. Piping Flexibility


    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  1. 46 CFR 154.503 - Piping and piping system components: Protection from movement.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Piping and piping system components: Protection from..., Construction and Equipment Cargo and Process Piping Systems § 154.503 Piping and piping system components... cause stresses that exceed the design stresses, the piping and piping system components and cargo...

  2. Reynolds stress scaling in pipe flow turbulence—first results from CICLoPE

    Örlü, R.; Fiorini, T.; Segalini, A.; Bellani, G.; Talamelli, A.; Alfredsson, P. H.


    This paper reports the first turbulence measurements performed in the Long Pipe Facility at the Center for International Cooperation in Long Pipe Experiments (CICLoPE). In particular, the Reynolds stress components obtained from a number of straight and boundary-layer-type single-wire and X-wire probes up to a friction Reynolds number of 3.8×104 are reported. In agreement with turbulent boundary-layer experiments as well as with results from the Superpipe, the present measurements show a clear logarithmic region in the streamwise variance profile, with a Townsend-Perry constant of A2≈1.26. The wall-normal variance profile exhibits a Reynolds-number-independent plateau, while the spanwise component was found to obey a logarithmic scaling over a much wider wall-normal distance than the other two components, with a slope that is nearly half of that of the Townsend-Perry constant, i.e. A2,w≈A2/2. The present results therefore provide strong support for the scaling of the Reynolds stress tensor based on the attached-eddy hypothesis. Intriguingly, the wall-normal and spanwise components exhibit higher amplitudes than in previous studies, and therefore call for follow-up studies in CICLoPE, as well as other large-scale facilities.

  3. Crack stability in a representative piping system under combined inertial and seismic/dynamic displacement-controlled stresses. Subtask 1.3 final report

    Scott, P.; Olson, R.; Wilkowski, O.G.; Marschall, C.; Schmidt, R.


    This report presents the results from Subtask 1.3 of the International Piping Integrity Research Group (IPIRG) program. The objective of Subtask 1.3 is to develop data to assess analysis methodologies for characterizing the fracture behavior of circumferentially cracked pipe in a representative piping system under combined inertial and displacement-controlled stresses. A unique experimental facility was designed and constructed. The piping system evaluated is an expansion loop with over 30 meters of 16-inch diameter Schedule 100 pipe. The experimental facility is equipped with special hardware to ensure system boundary conditions could be appropriately modeled. The test matrix involved one uncracked and five cracked dynamic pipe-system experiments. The uncracked experiment was conducted to evaluate piping system damping and natural frequency characteristics. The cracked-pipe experiments evaluated the fracture behavior, pipe system response, and stability characteristics of five different materials. All cracked-pipe experiments were conducted at PWR conditions. Material characterization efforts provided tensile and fracture toughness properties of the different pipe materials at various strain rates and temperatures. Results from all pipe-system experiments and material characterization efforts are presented. Results of fracture mechanics analyses, dynamic finite element stress analyses, and stability analyses are presented and compared with experimental results.

  4. Stress and Fracture Strength Analysis for Three-Way Pipes%三通管道的应力与断裂强度分析

    许京荆; 吴益民


    Three-way pipes, T and Y pipes, are very important connecting components in pipeline systems, their strength are related to the safety of pipelines. In the case that crack is not detected in the three-way pipe, ANSYS finite element program version 5.6 is applied to study the stress distribution of the three-way pipe and to obtain the optimum fillet radius in the crotch region of the two pipes. The reasonable intersection angle φ of the two pipes is also obtained. In the case that a surface crack is detected in the three-way pipe, the maximum stress intensity factor (SIF) near the front of the surface crack is studied.

  5. Research on Stress Calculation of the Boiler Steam Pipe%对锅炉汽水管道应力的计算研究

    廉平; 冯婷婷


    文章对锅炉汽水管道的应力进行分析,对锅炉汽水管道的应力计算进行了研究。%This paper analyzes the stress of the boiler and steam pipe, the stress calculation of the boiler and steam pipe is studied.

  6. Influence of residual stress on the HIC resistance of high frequency induction welded pipes with regard to process-specific influencing factors

    Krageloh, Joachim; Brauer, Holger; Bosch, Christoph [Salzgitter Mannesmann Line Pipe GmbH, (Germany)


    The industry needs to meet growing demand for pipes with high resistance to sour service conditions. Salzgitter Mannesmann Line Pipe is developing new product ranges of high frequency induction (HFI) welded pipes. This study investigated the influence of residual stress on the resistance of HFI welded pipes to HIC with focus on process-specific influencing factors. Four materials with different strengths were tested. Three of them were not manufactured for sour service and so were sure to show significant HIC damage during the tests. The specimens were studied using the cross-sectioning method for longitudinal and circumferential residual stress. A four-point-bend test in line with ADTM G 39 was also done to determine the HIC resistance of the pipe specimens. The results provide a characteristic HIC value and crack area ratio, CAR. This study showed that residual stress induced by HFI welding of pipes has no negative impact on resistance to HIC.

  7. Stress Analysis of the Centrifugal Pump Pipe%离心泵管道应力浅析



    结合离心泵管口受力要求及应力分析原则,分析与探讨如何建立离心泵管道应力计算模型,涉及泵的模拟、管道计算温度的选取、泵与储罐之间的柔性连接,以及泵管口受力和力矩的控制途径等。%Combine the force requirements and stress principles of the centrifugal pump pipe nozzle ,analyze and discuss how to establish the stress calculation model of the centrifugal pump ,w hich including the pump simulation ,pipe calculated temperature option , flexible connection between the pump and tank ,and control ways for pump pipe nozzle force and moment of force .

  8. Piping Analysis


    Burns & McDonnell provide architectural and engineering services in planning, design and construction of a wide range of projects all over the world. In design analysis, company regularly uses COSMIC computer programs. In computer testing piping design of a power plant, company uses Pipe Flexibility Analysis Program (MEL-21) to analyze stresses due to weight, temperature, and pressure found in proposed piping systems. Individual flow rates are put into the computer, then computer calculates the pressure drop existing across each component; if needed, design corrections or adjustments can be made and rechecked.

  9. Comparison Between Stress Obtained by Numerical Analysis and In-Situ Measurements on a Flexible Pipe Subjected to In-Plane Bending Test

    Vestergaard Lukassen, Troels; Glejbøl, Kristian; Lyckegaard, Anders


    variations will allow for performance optimization of the armour layers. To study the detailed stress variations in flexible pipes during dynamic loading, a comprehensive three-dimensional implicit nonlinear finite element model has been developed. The predicted numerical stress variations will be compared......To predict the lifetime and long-term properties of tensile armour wires in a dynamically loaded pipe, it is essential to have a tool which allows detailed prediction of the stress variations in the tensile armour wires during global pipe loading. Furthermore, detailed understanding of the stress...

  10. Reynolds stress scaling in pipe flow turbulence-first results from CICLoPE.

    Örlü, R; Fiorini, T; Segalini, A; Bellani, G; Talamelli, A; Alfredsson, P H


    This paper reports the first turbulence measurements performed in the Long Pipe Facility at the Center for International Cooperation in Long Pipe Experiments (CICLoPE). In particular, the Reynolds stress components obtained from a number of straight and boundary-layer-type single-wire and X-wire probes up to a friction Reynolds number of 3.8×10(4) are reported. In agreement with turbulent boundary-layer experiments as well as with results from the Superpipe, the present measurements show a clear logarithmic region in the streamwise variance profile, with a Townsend-Perry constant of A2≈1.26. The wall-normal variance profile exhibits a Reynolds-number-independent plateau, while the spanwise component was found to obey a logarithmic scaling over a much wider wall-normal distance than the other two components, with a slope that is nearly half of that of the Townsend-Perry constant, i.e. A2,w≈A2/2. The present results therefore provide strong support for the scaling of the Reynolds stress tensor based on the attached-eddy hypothesis. Intriguingly, the wall-normal and spanwise components exhibit higher amplitudes than in previous studies, and therefore call for follow-up studies in CICLoPE, as well as other large-scale facilities.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).

  11. Interfacial shear stress in stratified flow in a horizontal rectangular duct

    Lorencez, C.; Kawaji, M. [Univ. of Toronto (Canada); Murao, Y. [Tokushima Univ. (Japan)] [and others


    Interfacial shear stress has been experimentally examined for both cocurrent and countercurrent stratified wavy flows in a horizontal interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress values at high gas flow rates which could be attributed to the assumptions and procedures involved in each method. The interfacial waves and secondary motions were also found to have significant effects on the accuracy of Reynolds stress and turbulence kinetic energy extrapolation methods.

  12. Three-dimensional finite element analysis for estimation of the weld residual stress in the dissimilar butt weld piping

    Lee, Kyoung Soo; Kim, Man Won; Lee, Sung Ho [KHNP Central Research Institute, Daejeon (Korea, Republic of)


    Numerous dissimilar metal welds are used to connect carbon steel and stainless steel in nuclear power plants. Recently, some cracks have occurred in the dissimilar metal welds, and welding residual stress is considered as a contributing factor to the cracks. In this study, welding residual stresses in dissimilar butt weld piping were evaluated by the 3-dimensional (3-D) finite element method. Welding residual stresses along the circumference of heat affected zones as well as weld regions were obtained through the analysis, which could not be obtainable with 2-dimensional (2-D) analysis. The differences between 2-D analysis and 3-D analysis are presented in this paper.

  13. Protective effect of low dose of melatonin against cholestatic oxidative stress after common bile duct ligation in rats

    Mukaddes Esrefoglu; Mehmet Gül; Memet Hanifi Emre; Alaattin Polat; Mukadder Ayse Selimoglu


    AIM: To investigate the role of oxidative injury and the effect of exogenous melatonin administration on liver damage induced by bile duct ligation (BDL), and second,to evaluate the role of nitric oxide (NO), a free oxygen radical, in oxidative injury.METHODS: Thirty-two Sprague-Dawley rats were assigned to four groups: sham operation (SO), BDL, BDL+melatonin,and BDL+vehicle. Cholestasis was achieved by double ligature of the common bile duct. Melatonin was injected intraperitoneally 500 μg/(kg.d) for 8 d. Hepatic oxidative stress markers were evaluated by changes in the amount of lipid peroxides, measured as malondialdehyde (MDA),and reduced GSH. Total nitrite (NOx) concentrations were determined in hepatic homogenates. Histopathological examination was performed using a histological scoring system.RESULTS: The histopathological changes including portal inflammation, necrosis, apoptosis, focal inflammation and fibrosis were severe in the BDL and BDL+vehicle groups. There were numerous large areas of coagulation necrosis. Histological Activity Index scores of these groups were significantly higher than that of the SO group. Treatment with melatonin reduced these alterations significantly. The degree of necro-infiammation and fibrosis showed significant difference between the BDL and BDL+melatonin groups. BDL was accompanied by a significant increase in MDA and NOx, and a significant decrease in GSH levels. Mean±SE values of MDA, GSH and NOx levels of SO group were 147.47±6.69, 0.88±0.33 μmol/g and 180.70±6.58 nm/g, respectively. The values of BDL group were 200.14±21.30, 0.65±0.02 μmol/g, and 400.46±48.89 nm/g, respectively, whereas the values of BDL+melatonin group were 115.93±6.8, 0.74±0.02 μmol/g,and 290.38±32.32 nm/g, respectively. Melatonin treatment was associated with a significant recovery of MDA, GSH and NOx levels.CONCLUSION: We have concluded that oxidative stress is associated with the pathogenesis of cholestatic liver damage and NO

  14. Surface stress effect on the vibration and instability of nanoscale pipes conveying fluid based on a size-dependent Timoshenko beam model

    Ansari, R.; Gholami, R.; Norouzzadeh, A.; Darabi, M. A.


    Presented in this paper is a precise investigation of the effect of surface stress on the vibration characteristics and instability of fluid-conveying nanoscale pipes. To this end, the nanoscale pipe is modeled as a Timoshenko nanobeam. The equations of motion of the nanoscale pipe are obtained based on Hamilton's principle and the Gurtin-Murdoch continuum elasticity incorporating the surface stress effect. Afterwards, the generalized differential quadrature method is employed to discretize the governing equations and associated boundary conditions. To what extent important parameters such as the thickness, material and surface stress modulus, residual surface stress, surface density, and boundary conditions influence the natural frequency of nanoscale pipes and the critical velocity of fluid is discussed.

  15. Quantifying turbulent wall shear stress in a stenosed pipe using large eddy simulation.

    Gårdhagen, Roland; Lantz, Jonas; Carlsson, Fredrik; Karlsson, Matts


    Large eddy simulation was applied for flow of Re=2000 in a stenosed pipe in order to undertake a thorough investigation of the wall shear stress (WSS) in turbulent flow. A decomposition of the WSS into time averaged and fluctuating components is proposed. It was concluded that a scale resolving technique is required to completely describe the WSS pattern in a subject specific vessel model, since the poststenotic region was dominated by large axial and circumferential fluctuations. Three poststenotic regions of different WSS characteristics were identified. The recirculation zone was subject to a time averaged WSS in the retrograde direction and large fluctuations. After reattachment there was an antegrade shear and smaller fluctuations than in the recirculation zone. At the reattachment the fluctuations were the largest, but no direction dominated over time. Due to symmetry the circumferential time average was always zero. Thus, in a blood vessel, the axial fluctuations would affect endothelial cells in a stretched state, whereas the circumferential fluctuations would act in a relaxed direction.

  16. Turbulent stresses and particle break-up criteria in particle-laden pipe flows

    Oliveira, J.L.G.; van der Geld, C.W.M.; Kuerten, Johannes G.M.

    Three-dimensional particle tracking velocimetry (3D-PTV) is applied to particle-laden pipe flows at Reynolds number 10,300, based on the bulk velocity and the pipe diameter. The effects of flow direction (upward or downward) and mean concentration (in the range 0.5 105–3.2 105) on the production of

  17. Application of the results of pipe stress analyses into fracture mechanics defect analyses for welds of nuclear piping components; Uebernahme der Ergebnisse von Rohrsystemanalysen (Spannungsanalysen) fuer bruchmechanische Fehlerbewertungen fuer Schweissnaehte an Rohrleitungsbauteilen in kerntechnischen Anlagen

    Dittmar, S.; Neubrech, G.E.; Wernicke, R. [TUeV Nord SysTec GmbH und Co.KG (Germany); Rieck, D. [IGN Ingenieurgesellschaft Nord mbH und Co.KG (Germany)


    For the fracture mechanical assessment of postulated or detected crack-like defects in welds of piping systems it is necessary to know the stresses in the un-cracked component normal to the crack plane. Results of piping stress analyses may be used if these are evaluated for the locations of the welds in the piping system. Using stress enhancing factors (stress indices, stress factors) the needed stress components are calculated from the component specific sectional loads (forces and moments). For this procedure the tabulated stress enhancing factors, given in the standards (ASME Code, German KTA regulations) for determination and limitation of the effective stresses, are not always and immediately adequate for the calculation of the stress component normal to the crack plane. The contribution shows fundamental possibilities and validity limits for adoption of the results of piping system analyses for the fracture mechanical evaluation of axial and circumferential defects in welded joints, with special emphasis on typical piping system components (straight pipe, elbow, pipe fitting, T-joint). The lecture is supposed to contribute to the standardization of a code compliant and task-related use of the piping system analysis results for fracture mechanical failure assessment. [German] Fuer die bruchmechanische Bewertung von postulierten oder bei der wiederkehrenden zerstoerungsfreien Pruefung detektierten rissartigen Fehlern in Schweissnaehten von Rohrsystemen werden die Spannungen in der ungerissenen Bauteilwand senkrecht zur Rissebene benoetigt. Hierfuer koennen die Ergebnisse von Rohrsystemanalysen (Spannungsanalysen) genutzt werden, wenn sie fuer die Orte der Schweissnaehte im Rohrsystem ausgewertet werden. Mit Hilfe von Spannungserhoehungsfaktoren (Spannungsindizes, Spannungsbeiwerten) werden aus den komponentenweise berechneten Schnittlasten (Kraefte und Momente) die benoetigten Spannungskomponenten berechnet. Dabei sind jedoch die in den Regelwerken (ASME

  18. Residual stress distributions in a P91 steel-pipe girth weld before and after post weld heat treatment

    Paddea, S., E-mail: [Materials Engineering, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Francis, J.A. [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Paradowska, A.M. [ISIS Facility, Rutherford-Appleton Laboratory, Didcot OX11 0QX, Oxon (United Kingdom); Bouchard, P.J. [Materials Engineering, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Shibli, I.A. [European Technology Development Ltd., Leatherhead KT22 7RD, Surrey (United Kingdom)


    Highlights: Black-Right-Pointing-Pointer Residual stresses in a pipe girth weld in P91 steel have been measured in both the as-welded and PWHT conditions. Black-Right-Pointing-Pointer The highest tensile residual stresses coincided with the HAZ boundary and the microstructural region that is prone to type IV cracking. Black-Right-Pointing-Pointer Compressive residual stresses were measured in the weld metal, in a location corresponding to the final weld pass. Black-Right-Pointing-Pointer The location of the peak compressive stresses can be explained by the effect of solid-state phase transformation. - Abstract: In this study the residual stresses in a pipe girth weld in a ferritic-martensitic power plant steel were measured by neutron diffraction and compared with the corresponding metallurgical zones in the weld region. It was found that, in both the as-welded and post-weld heat treated condition, the highest tensile stresses resided near the outer boundary of the heat-affected zone (HAZ), and towards the weld root region. Substantial tensile direct and hydrostatic stresses existed across the HAZ, including the fine-grained and intercritically annealed regions, where premature type IV creep failures manifest in 9-12 Cr steel welds. Compressive stresses were found in the weld metal coinciding with the last weld bead to be deposited. Constrained cooling tests on test coupons illustrated that these compressive stresses can be explained in terms of the influence that solid-state phase transformations have on the accumulation of stress in welds.

  19. Effect of width of repair welding on stress distribution of dissimilar metal butt weld of nuclear piping

    Hwang, Won Shik; Lee, Hwee Seung; Huh, Nam Su [Seoul National Univ. of Science and Technology, Seoul (Korea, Republic of)


    In the present work, the welding residual stress due to repair welding and the stress redistribution behavior due to primary pressure are investigated via 2-dimensional non-linear finite element analyses. In particular, the effect of repair welding width on stress distribution is emphasized. Although, large tensile residual stresses are produced at the PWSCC sensitive region due to repair welding, these stresses are highly reduced due to stress redistribution caused by primary load. Based on the present finite element results, it has been revealed that the effect of width of repair welding on stress distribution is not significant. In the past few years, many numerical and experimental works have been made to assess a structural integrity of cracked components subjected to primary water stress corrosion cracking in dissimilar metal weld (DMW) using Alloys 82/182 in nuclear industries worldwide. These works include a prediction of weld residual stresses in dissimilar metal weld by either numerical or experimental works since an accurate estimation of residual stress distribution in dissimilar metal weld is the most important element for integrity assessment of components subjected to primary water stress corrosion cracking. During an actual welding process, in general, a repair welding is often performed when a defect indication is detected during post-welding inspection. It has been revealed that such a repair welding could lead to higher tensile residual stress in dissimilar metal weld, which is detrimental to the crack growth due to primary water stress corrosion cracking. Thus, the prediction of residual stress considering a repair welding is needed, and then many efforts were made on this issue. In the present work, the effect of width of repair welding on stress distribution of dissimilar metal butt weld of nuclear piping is evaluated based on the detailed 2-dimensional non-linear finite element analyses. For this purpose, the welding residual stress due to

  20. Reynolds shear stress and heat flux calculations in a fully developed turbulent duct flow

    Antonia, R. A.; Kim, J.


    The use of a modified form of the Van Driest mixing length for a fully developed turbulent channel flow leads to mean velocity and Reynolds stress distributions that are in close agreement with data obtained either from experiments or direct numerical simulations. The calculations are then extended to a nonisothermal flow by assuming a constant turbulent Prandtl number, the value of which depends on the molecular Prandtl number. Calculated distributions of mean temperature and lateral heat flux are in reasonable agreement with the simulations. The extension of the calculations to higher Reynolds numbers provides some idea of the Reynolds number required for scaling on wall variables to apply in the inner region of the flow.

  1. Simulation of bending stress variation in long buried thick-walled pipes under the earth’s movement using combined linear dynamics and beam theories

    Salau Tajudeen A.O.


    Full Text Available This study reported a simulation approach to the understanding of the interactions between a buried pipe and the soil system by computing the bending stress variation of harmonically-excited buried pipes. The established principles of linear dynamics theory and simple beam theory were utilised in the analysis of the problem of buried pipe bending stress accumulation and its dynamics. With regards to the parameters that influence the bending stress variations, the most important are the isolation factor, uniform external load, and the corresponding limiting conditions. The simulated mathematical expressions, containing static and dynamic parameters of the buried pipe and earth, were coded in Fortran programming language and applied in the simulation experiment. The results obtained showed that harmonically-excited buried thick-walled pipe became stable and effective when the ratio of the natural frequency of vibration to the forced frequency is greater than 2.0, whenever the damped factor is used as the control parameter for the maximum bending stress. The mirror image of the stress variation produces variation in the location of the maximum bending stress in quantitative terms. The acceptable pipe materials for the simulated cases must have yield strength in bending greater than or equal to 13.95 MPa. The results obtained in this work fill a gap in the literature and will be useful to pipeline engineers and designers, as well as to environmental scientists in initialising and controlling environmental issues and policy formulation concerning the influence of buried pipe on the soil and water in the environment.

  2. Studies of the Wall Shear Stress in a Turbulent Pulsating Pipe Flow


    00),y(200),a Ifa(200), bata), duy(33) 33,^00),uffទ, 2) in re,vis,fr,ns/perlod, nprds ’ fr,ns, nprds rad lus of pipe’ re**.375 bt, hk ’ s/w...c input: re reynolds number c VIS viscosity fr frequency c c ns time steps per period c nprds periods to be...f r, ns / per i od, nprds ’ readJt, revis, fr, ns, nprds prints, ’type in radius of the pipe and amplitude of velocity readH,rO gama ’ printi

  3. VLCC前置导管结构设计与强度分析%Structure Design and Stress Assessment of Wake Equalizing Duct for VLCC

    刘奕谦; 谢小龙


    An assessment on resonance risk for a wake equalizing duct is made in this article. By using finite element method and boundary element method, natural frequencies and mode shapes of the wake equalizing duct are got in both air and water. Different strengthening methods are compared and analyzed, and appropriate wake equalizing duct structure design is determined ultimately. According to the requirements of hull load by IACS Common Structural Rules (CSR) and Germanischer Lloyd (GL Rules), possible load on the wake equalizing duct structure in actual operations is analyzed. A three-dimensional finite element model of wake equalizing duct is established, and structural stress levels under various combinations of loads are checked. Design methods of wake equalizing duct structure are investigated by using a simple mechanical model and estimation formulae are verified with finite element analysis.%应用有限元法和流体边界元法得到导管在空气中和水中的固有频率和振型,并对不同的加强方案进行比较分析,最终确定合适的导管结构设计方案。根据IACS共同结构规范(CSR)及德国劳氏船级社(GL RULES)关于船体载荷的要求,对前置导管结构在实际运营中可能受到的载荷进行定量分析。通过建立前置导管三维有限元模型,根据不同载荷组合对导管结构应力水平进行有限元分析校核。并利用简单的力学模型,探讨了导管结构设计验证的方法和剖面模数估算公式。

  4. Numerical simulation of turbulent flow in corrugated pipes

    Azevedo, Henrique S. de; Morales, Rigoberto E.M.; Franco, Admilson T.; Junqueira, Silvio L.M.; Erthal, Raul H. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Dept. Academico de Mecanica (DAMEC)]. E-mails:;;;;; Goncalves, Marcelo de Albuquerque Lima [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)]. E-mail:


    Corrugated pipes are used in various engineering applications such heat exchangers and oil transport. In most cases these pipes consist of periodically distributed grooves at the duct inner wall. Numerical and experimental works reported the influence of grooves height and length in the turbulent flow by inspection of several turbulent properties such as velocity fluctuations and Reynolds stress. The present article aims to investigate the influence of grooves height and length in the global friction factor of turbulent flow through periodically corrugated pipes. Mass and momentum conservation equations are revised and specific boundary conditions are set to characterize a periodic fully developed regime in a single axisymmetric bidimensional module which represents the periodically corrugated duct geometry. The set of algebraic equations is discretized through the Finite Volume Method, with the Hybrid interpolation scheme applied to the convective terms, and solved using the commercial software PHOENICS CFD. The simulation of turbulent, incompressible, isothermal and single-phase flow is considered. The algebraic turbulence model LVEL is used. Four geometric configurations are assumed, including grooves height and length variations, in order to compare their influence on the friction factor. The obtained numerical friction factors show good agreement with previous experimental results, specially for Reynolds numbers over 20000. Numerical results for corrugated pipes compared to the Blasius smooth pipe correlation shows that the friction factor increases compared to smooth pipes, and such increase is more significant for higher Reynolds numbers and for larger grooves as well. These trends appear to be related to an enhancement of the momentum transport over the corrugated wall due to the recirculating pattern inside the grooves, in accordance with previous experimental works (author)

  5. 3D mapping of reinforcement and tendon ducts on pre-stressed concrete bridges by means of Ground Penetrating Radar (GPR)

    Cheilakou, E.; Theodorakeas, P.; Koui, M.; Zeris, C.


    The present study evaluates the potential of GPR for the inspection of pre-stressed concrete bridges and its usefulness to provide non visible information of the interior structural geometry and condition, required for strengthening and rehabilitation purposes. For that purpose, different concrete blocks of varying dimensions with embedded steel reinforcement bars, tendon ducts and fabricated voids, were prepared and tested by means of GPR in a controlled laboratory environment. 2D data acquisition was carried out in reflection mode along single profile lines of the samples in order to locate the internal structural elements. 3D surveys were also performed in a grid format both along horizontal and vertical lines, and the individual profiles collected were interpolated and further processed using a 3D reconstruction software, in order to provide a detailed insight into the concrete structure. The obtained 2D profiles provided the accurate depth and position of the embedded rebars and tendon ducts, verifying the original drawings. 3D data cubes were created enabling the presentation of depth slices and providing additional information such as shape and localization of the internal elements. The results obtained from this work showed the effectiveness and reliability of the GPR technique for pre-stressed concrete bridge investigations.

  6. Stress Distribution in the Dissimilar Metal Butt Weld of Nuclear Reactor Piping due to the Simulation Technique for the Repair Welding

    Lee, Hweeseung; Huh, Namsu [Seoul Nat' l Univ. of Science and Technology, Seoul (Korea, Republic of); Kim, Jinsu; Lee, Jinho [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)


    During welding, the dissimilar metal butt welds of nuclear piping are typically subjected to repair welding in order to eliminate defects that are found during post-weld inspection. It has been found that the repair weld can significantly increase the tensile residual stress in the weldment, and therefore, accurate estimation of the weld residual stress due to repair weld, especially for dissimilar metal welds using Ni-based alloy 82/182 in nuclear components, is of great importance in order to assess susceptibility to primary water stress corrosion cracking. In the present study, the stress distributions of dissimilar metal butt welds in nuclear reactor piping subjected to repair weld were investigated based on detailed nonlinear finite element analyses. Particular emphasis was placed on the variation of the stress distribution in the dissimilar metal butt weld according to the finite element welding analysis sequence for the repair welding process.


    Jianjun Luo


    Full Text Available In recent years, a big number of large diameter pre-stressed concrete cylinder pipe (PCCP lines have been applied to the Mid-route of the South-to-North Water Transfer Project. However, the leakage problem of PCCP causes annually heavy economic losses to our country. In such a context of situation, how to detect leaks rapidly and precisely after pipes appear cracks in water supply system has great significance. Based on the study and analysis of the characteristic structure of large diameter PCCP, a new leak detection system using fiber Bragg grating sensors, which can capture signals of water pressure change, is proposed. The feasibility, reliability and practicability of the system could be acceptable according to data achieved from in–situ tests. Moreover, the leak detection system can monitor in real-time of dynamic change of water pressure. The equations of the leakage quantity and water pressure have been presented in this paper, which can provide technical guidelines for large diameter PCCP lines maintenance.

  8. Characterization of the secondary flow in hexagonal ducts

    Marin, O.; Vinuesa, R.; Obabko, A. V.; Schlatter, P.


    In this work we report the results of DNSs and LESs of the turbulent flow through hexagonal ducts at friction Reynolds numbers based on centerplane wall shear and duct half-height Reτ,c ≃ 180, 360, and 550. The evolution of the Fanning friction factor f with Re is in very good agreement with experimental measurements. A significant disagreement between the DNS and previous RANS simulations was found in the prediction of the in-plane velocity, and is explained through the inability of the RANS model to properly reproduce the secondary flow present in the hexagon. The kinetic energy of the secondary flow integrated over the cross-sectional area yz decreases with Re in the hexagon, whereas it remains constant with Re in square ducts at comparable Reynolds numbers. Close connection between the values of Reynolds stress u w ¯ on the horizontal wall close to the corner and the interaction of bursting events between the horizontal and inclined walls is found. This interaction leads to the formation of the secondary flow, and is less frequent in the hexagon as Re increases due to the 120∘ aperture of its vertex, whereas in the square duct the 90∘ corner leads to the same level of interaction with increasing Re. Analysis of turbulence statistics at the centerplane and the azimuthal variance of the mean flow and the fluctuations shows a close connection between hexagonal ducts and pipe flows, since the hexagon exhibits near-axisymmetric conditions up to a distance of around 0.15DH measured from its center. Spanwise distributions of wall-shear stress show that in square ducts the 90∘ corner sets the location of a high-speed streak at a distance zv+≃50 from it, whereas in hexagons the 120∘ aperture leads to a shorter distance of zv+≃38 . At these locations the root mean square of the wall-shear stresses exhibits an inflection point, which further shows the connections between the near-wall structures and the large-scale motions in the outer flow.

  9. Mitigation of stress corrosion cracking in pressurized water reactor (PWR) piping systems using the mechanical stress improvement process (MSIP{sup R)} or underwater laser beam welding

    Rick, Grendys; Marc, Piccolino; Cunthia, Pezze [Westinghouse Electric Company, LLC, New York (United States); Badlani, Manu [Nu Vision Engineering, New York (United States)


    A current issue facing pressurized water reactors (PWRs) is primary water stress corrosion cracking (PWSCC) of bi metallic welds. PWSCC in a PWR requires the presence of a susceptible material, an aggressive environment and a tensile stress of significant magnitude. Reducing the potential for SCC can be accomplished by eliminating any of these three elements. In the U.S., mitigation of susceptible material in the pressurizer nozzle locations has largely been completed via the structural weld overlay (SWOL) process or NuVision Engineering's Mechanical Stress Improvement Process (MSIP{sup R)}, depending on inspectability. The next most susceptible locations in Westinghouse designed power plants are the Reactor Vessel (RV) hot leg nozzle welds. However, a full SWOL Process for RV nozzles is time consuming and has a high likelihood of in process weld repairs. Therefore, Westinghouse provides two distinctive methods to mitigate susceptible material for the RV nozzle locations depending on nozzle access and utility preference. These methods are the MSIP and the Underwater Laser Beam Welding (ULBW) process. MSIP applies a load to the outside diameter of the pipe adjacent to the weld, imposing plastic strains during compression that are not reversed after unloading, thus eliminating the tensile stress component of SCC. Recently, Westinghouse and NuVision successfully applied MSIP on all eight RV nozzles at the Salem Unit 1 power plant. Another option to mitigate SCC in RV nozzles is to place a barrier between the susceptible material and the aggressive environment. The ULBW process applies a weld inlay onto the inside pipe diameter. The deposited weld metal (Alloy 52M) is resistant to PWSCC and acts as a barrier to prevent primary water from contacting the susceptible material. This paper provides information on the approval and acceptance bases for MSIP, its recent application on RV nozzles and an update on ULBW development.

  10. Predicting welding residual stresses in a dissimilar metal girth welded pipe using 3D finite element model with a simplified heat source

    Deng, Dean, E-mail: [College of Materials Science and Engineering, Chongqing University, Shazheng Street 174, Shapingba, Chongqing 400044 (China); Kiyoshima, Shoichi [Research Center of Computational Mechanics, Inc., Togoshi NI-Bldg., 1-7-1 Togoshi, Shinagawa-ku, Tokyo 142-0041 (Japan); Ogawa, Kazuo [Japan Nuclear Energy Safety Organization, TOKYU REIT Toranomon Bldg, 3-17-1, Toranomon, Minato-ku, Tokyo 105-0001 (Japan); Yanagida, Nobuyoshi [Hitachi Ltd. 1-1, Saiwa-cho 3-chome, Hitachi-shi, Ibaraki-ken 317-8511 (Japan); Saito, Koichi [Hitachi-GE Nuclear Energy, Ltd. 2-2, Omika-cho, 5-chome, Hitachi-shi, Ibaraki-ken 319-1221 (Japan)


    Research highlights: Welding residual stresses have asymmetrical distributions in the dissimilar metal pipe. Variable length heat source model can largely save computing time. Besides welding, other thermal processes also affect residual stresses. - Abstract: Dissimilar metal welds are commonly used in nuclear power plants to connect low alloy steel components and austenitic stainless steel piping systems. The integrity assessment and life estimation for such welded structures require consideration of residual stresses induced by manufacturing processes. Because the fabrication process of dissimilar metal weld joints is considerably complex, it is very difficult to accurately predict residual stresses. In this study, both numerical simulation technology and experimental method were used to investigate welding residual stress distribution in a dissimilar metal pipe joint with a medium diameter, which were performed by a multi-pass welding process. Firstly, an experimental mock-up was fabricated to measure the residual stress distributions on the inside and the outside surfaces. Then, a time-effective 3-D finite element model was developed to simulate welding residual stresses through using a simplified moving heat source. The simplified heat source method could complete the thermo-mechanical analysis in an acceptable time, and the simulation results generally matched the measured data near the weld zone. Through comparing the simulation results and the experimental measurements, we can infer that besides the multi-pass welding process other key manufacturing processes such as cladding, buttering and heat treatment should also be taken into account to accurately predict residual stresses in the whole range of the dissimilar metal pipe.

  11. Mammary Duct Ectasia

    ... tenderness or inflammation of the clogged duct (periductal mastitis). Mammary duct ectasia most often occurs in women ... that's turned inward (inverted) A bacterial infection called mastitis also may develop in the affected milk duct, ...

  12. 3-D FEM Analysis of Stress Distribution for Connecting Pipe in Mid-pressure Steam Drum%中压汽包接管应力分布的三维有限元分析

    杨伟春; 梁基照


    In this paper a stress distribution analysis for connecting pipes in a mid-pressure steam drum has been made by means of the 3-dimensional finite element of ANSYS structure analysis software.The results showed that the maximum values of all kinds of stresses were in the inside of the conjunction area betw een the pipe and the steam-drum cylinder,and these stresses decreased with incre asing distance from this area.

  13. Application of Entropy Concept for Shear Stress Distribution in Laminar Pipe Flow

    Choo, Yeon Moon; Choo, Tai Ho; Jung, Donghwi; Seon, Yun Gwan; Kim, Joong Hoon


    In the river fluid mechanics, shear stress is calculated from frictional force caused by viscosity and fluctuating velocity. Traditional shear stress distribution equations have been widely used because of their simplicity. However, they have a critical limitation of requiring energy gradient which is generally difficult to estimate in practice. Especially, measuring velocity/velocity gradient on the boundary layer is difficult in practice. It requires point velocity throughout the entire cross section to calculate velocity gradient. This study proposes shear stress distribution equations for laminar flow based on entropy theory using mean velocity and entropy coefficient. The proposed equations are demonstrated and compared with measured shear stress distribution using Nikuradse's data. Results showed that the coefficient of determination is around 0.99 indicating that the proposed method well describes the true shear stress distribution. Therefore, it was proved that shear stress distribution can be easily and accurately estimated by using the proposed equations. (This research was supported by a gran(13AWMP-B066744-01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean Government)

  14. Nose-only water-pipe smoking effects on airway resistance, inflammation, and oxidative stress in mice.

    Nemmar, Abderrahim; Raza, Haider; Yuvaraju, Priya; Beegam, Sumaya; John, Annie; Yasin, Javed; Hameed, Rasheed S; Adeghate, Ernest; Ali, Badreldin H


    Water-pipe smoking (WPS) is a common practice in the Middle East and is now gaining popularity in Europe and the United States. However, there is a limited number of studies on the respiratory effects of WPS. More specifically, the underlying pulmonary pathophysiological mechanisms related to WPS exposure are not understood. Presently, we assessed the respiratory effects of nose-only exposure to mainstream WPS generated by commercially available honey flavored "moasel" tobacco. The duration of the session was 30 min/day and 5 days/wk for 1 mo. Control mice were exposed to air only. Here, we measured in BALB/c mice the airway resistance using forced-oscillation technique. Lung inflammation was assessed histopathologically and by biochemical analysis of bronchoalveolar lavage (BAL) fluid, and oxidative stress was evaluated biochemically by measuring lipid peroxidation, reduced glutathione and several antioxidant enzymes. Pulmonary inflammation assessment showed an increase in neutrophil and lymphocyte numbers. Likewise, airway resistance was significantly increased in the WPS group compared with controls. Tumor necrosis factor α and interleukin 6 concentrations were significantly increased in BAL fluid. Lipid peroxidation in lung tissue was significantly increased whereas the level and activity of antioxidants including reduced glutathione, glutathione S transferase, and superoxide dismutase were all significantly decreased following WPS exposure, indicating the occurrence of oxidative stress. Moreover, carboxyhemoglobin levels were significantly increased in the WPS group. We conclude that 1-mo nose-only exposure to WPS significantly increased airway resistance, inflammation, and oxidative stress. Our results provide a mechanistic explanation for the limited clinical studies that reported the detrimental respiratory effects of WPS.

  15. Homage to Bob Brodkey at 85: Ejections, Sweeps and Reynolds Shear Stress Generation in Turbulent Pipe Flow

    Wallace, James M


    Almost 50 years ago Bob Brodkey and his student, Corino, conceived of and carried out a visualization experiment for the very near wall region of a turbulent pipe flow that, together with the turbulent boundary layer visualization of Kline et al., excited the turbulence research community. Using a high-speed movie camera mounted on a lathe bed that recorded magnified images in a frame of reference moving with the flow, they observed the motions of submicron particles in the sub-layer, buffer-layer and lower part of the log-layer. Surprisingly, these motions were not nearly so locally random as was the general view of turbulence at the time. Rather, connected regions of the near wall flow decelerated and then erupted away from the wall in what they called "ejections". These decelerated motions were followed by larger scale connected motions toward the wall from above that they called "sweeps". They estimated that ejections accounted for 70% of the Reynolds shear stress at Re_d = 20,000 while only occurring abo...

  16. 焊管残余应力研究进展及展望%Research Progress and Prospect of Residual Stress in Welded Pipe

    李霄; 熊庆人; 石凯; 刘彦明; 李健; 胥聪敏; 张燕娜


    During the manufacturing procedure,the pipe body was formed,welded,pressurized,bended and coated successively,and residual stress was induced into the pipe body which is closely related with the service life,and many researches are about it.In this paper the main residual stress studing methodes and main research results are reviewed.It has a very strong relationship between residual stess and forming process.The residual stress of general LSAW(Longitudinal Submerged Arc Welded) pipe is lower and more uniform than HSAW(Helical Submerged Arc Welded) pipe.Hydrotest and expanding process can effectively reduce residual stress,but the relationship among hydrotest pressure,expanding parameter and residual stress need to be defined through a lot of research.Meanwhile the application of ring-slit method and magnetic method,the model of HSAW pipe forming,the distribution along thickness of residual stress need to be studied deeply.%在焊管制造过程中需进行弯曲成型、焊接、水压、弯管、防腐等工艺过程,这些工艺过程造成的残余应力关系到焊管的服役寿命.介绍了焊管残余应力的研究方法、研究成果.指出,焊管的残余应力与其成型工艺关系重大,一般直缝焊管的残余应力水平低、分布均匀,螺旋焊管的残余应力水平高,且分布均匀性差.水压试验和扩径可以有效降低残余应力,但水压和扩径参数与残余应力的具体关系仍需要进行大量研究才能确定.最后指出,对切环法与磁测法的应用、螺旋焊管成型的精确模型、残余应力沿厚度方向的分布等问题仍需要进行深入研究.


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


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

  18. Numerical simulation of temperature and thermal stress for nuclear piping by using computational fluid dynamics analysis and Green’s function

    Boo, Myung-Hwan [Korea Hydro and Nuclear Power Company, Daejeon (Korea, Republic of); Oh, Chang-Kyun; Kim, Hyun-Su [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of); Choi, Choeng-Ryul [ELSOLTEC, Inc., Yongin (Korea, Republic of)


    Owing to the fact that thermal fatigue is a well-known damage mechanism in nuclear power plants, accurate stress and fatigue evaluation are highly important. Operating experience shows that the design condition is conservative compared to the actual one. Therefore, various fatigue monitoring methods have been extensively utilized to consider the actual operating data. However, defining the local temperature in the piping is difficult because temperature-measuring instruments are limited. The purpose of this paper is to define accurate local temperature in the piping and evaluate thermal stress using Green’s function (GF) by performing a series of computational fluid dynamics analyses considering the complex fluid conditions. Also, the thermal stress is determined by adopting GF and comparing it with that of the design condition. The fluid dynamics analysis result indicates that the fluid temperature slowly varies compared to the designed one even when the flow rate changes abruptly. In addition, the resulting thermal stress can significantly decrease when reflecting the actual temperature.

  19. Characterization of flow in a scroll duct

    Begg, E. K.; Bennett, J. C.


    A quantitative, flow visualization study was made of a partially elliptic cross section, inward curving duct (scroll duct), with an axial outflow through a vaneless annular cutlet. The working fluid was water, with a Re(d) of 40,000 at the inlet to the scroll duct, this Reynolds number being representative of the conditions in an actual gas turbine scroll. Both still and high speed moving pictures of fluorescein dye injected into the flow and illuminated by an argon ion laser were used to document the flow. Strong secondary flow, similar to the secondary flow in a pipe bend, was found in the bottom half of the scroll within the first 180 degs of turning. The pressure field set up by the turning duct was strong enough to affect the inlet flow condition. At 90 degs downstream, the large scale secondary flow was found to be oscillatory in nature. The exit flow was nonuniform in the annular exit. By 270 degs downstream, the flow appeared unorganized with no distinctive secondary flow pattern. Large scale structures from the upstream core region appeared by 90 degs and continued through the duct to reenter at the inlet section.

  20. H2S Stress Corrosion Test Research of the Spiral Welded Pipe%螺旋焊管H2S应力腐蚀的试验研究



    Through the spiral welded pipe H2S stress corrosion testresearch, the article gives out H2S stress corrosion resistance methods of the spiral welded pipe, and proposes some suggestion on the development of China H2S stress corrosion.%通过对螺旋焊管H2S应力腐蚀试验研究,提出了螺旋焊管抗H2S应力腐蚀的几种途径,并对我国H2S应力腐蚀的发展提出了一些建议。

  1. Early bile duct cancer

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


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

  2. Technical Letter Report - Analysis of Ultrasonic Data on Piping Cracks at Ignalina Nuclear Power Plant Before and After Applying a Mechanical Stress Improvement Process, JCN-N6319, Task 2

    Anderson, Michael T.; Cumblidge, Stephen E.; Crawford, Susan L.


    Pacific Northwest National Laboratory (PNNL) is assisting the United States Nuclear Regulatory Commission (NRC) in developing a position on the management of primary water stress corrosion cracking (PWSCC) in piping systems previously analyzed for leak-before-break (LBB). Part of this work involves determining whether inspections alone are sufficient or if inspections plus mitigation techniques are needed. The work described in this report addresses the reliability of ultrasonic phased-array (PA) examinations for inspection of cracks that have been subjected to the mitigation method of mechanical stress improvement process (MSIP). It is believed that stresses imparted during MSIP may make ultrasonic crack responses in piping welds more difficult to detect and accurately characterize. To explore this issue, data were acquired, both before and after applying MSIP, and analyzed from cracked areas in piping at the Ignalina Nuclear Power Plant (INPP) in Lithuania. This work was performed under NRC Project JCN-N6319, PWSCC in Leak-Before-Break Systems.

  3. Ultrasound stress measurements for API X65 pipes; Avaliacao por ultra-som das tensoes impostas em tubo API X-65

    Medeiros, Raimundo C.; Santos, Ramon Loback Medeiros [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil); Bittencourt, Marcelo S.Q.; Lamy, Carlos A. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Donato, Guilherme V.P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)


    Risks of damages or even premature collapse of buried pipelines caused by their interaction with geologically unstable soils are well-established phenomena. Therefore, both monitoring and measurements of the actual loads transmitted by the soil to the pipeline are mandatory requirements, and define the necessity of developing new nondestructive techniques capable to carry out through evaluations of these loads in field. The aim of this paper has been placed on the presentation of a cutting-edge ultrasonic technology applied to stress measurements. To accomplish this purpose a series of ultrasonic tests were conducted on tensile specimens extracted from API 5L Grade X-65 steel pipe to determine its acoustic birefringence. The results have evidenced the acoustic birefringence to be a technique sufficiently consistent and, consequently, it shall be considered as a promising tool for the evaluation of the structural integrity of metallic structures in the near future. In addition, it was also observed that the use of this technique allows measuring the residual stress resulting from the pipe manufacturing process. (author)

  4. Serum oxidative stress is increased in patients with post cholecystectomy bile duct injury Aumento del estrés oxidativo en el suero de pacientes con lesiones de vías biliares postcolecistectomía

    A. G. Miranda-Díaz


    Full Text Available Background: post-cholecystectomy bile duct injuries are identified by the onset of jaundice as well as elevated bilirubin and alkaline phosphatase levels during the peri-operative period. It is unknown how serum oxidative stress markers are modified in patients with post-cholecystectomy bile duct injuries. Objective: to determine serum oxidative stress marker levels (lipid peroxidation by-products, nitrites/nitrates and total antioxidant capacity in patients with post-cholecystectomy bile duct injuries. Patients and methods: a prospective, transversal and analytical study was designed with two groups. Group 1: 5 healthy volunteer subjects. Group 2: 52 patients with post-cholecystectomy bile duct injuries (43 female and 9 male. An elective bilio-digestive reconstruction was performed at week 8. The serum oxidative stress marker levels were quantified by colorimetric method. Results: patients with bile duct injuries had a significant increased serum lipid peroxides (malondialdehyde and 4-hydroxy-alkenals and nitric oxide metabolites (nitrites/nitrates levels compared to the control group. In contrast, total antioxidant capacity in patients with bile duct injuries remained similar compared to healthy controls. Conclusions: the results show that oxidative stress is usually associated to bile duct injury.Introducción: las lesiones de las vías biliares postcolecistectomía se establecen por la aparición de ictericia, elevación de las bilirrubinas y de la fosfatasa alcalina durante el periodo perioperatorio. Se desconoce cómo se modifican los marcadores de estrés oxidativo en el suero de los pacientes con lesiones de las vías biliares postcolecistectomía. Objetivo: determinar los marcadores de estrés oxidativo (productos de peroxidación de lípidos, catabolitos del óxido nítrico y capacidad antioxidante total en el suero de pacientes con lesiones de las vías biliares. Pacientes y métodos: se realizó un estudio prospectivo transversal

  5. Heat pipes

    Dunn, Peter D


    It is approximately 10 years since the Third Edition of Heat Pipes was published and the text is now established as the standard work on the subject. This new edition has been extensively updated, with revisions to most chapters. The introduction of new working fluids and extended life test data have been taken into account in chapter 3. A number of new types of heat pipes have become popular, and others have proved less effective. This is reflected in the contents of chapter 5. Heat pipes are employed in a wide range of applications, including electronics cooling, diecasting and injection mo

  6. Residual stress evaluation by X-Ray diffraction and hole-drilling in an API 5L X70 steel pipe bent by hot induction

    Ceglias, Rodrigo Braga; Alves, Juciane Maria; Botelho, Ramon Alves; Baeta Junior, Eustaquio de Souza; Santos, Igor Cuzzuol dos; Moraes, Nicki Robbers Darciano Cajueiro de; Oliveira, Rebeca Vieira de; Diniz, Saulo Brinco; Brandao, Luiz Paulo, E-mail: [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Mecanica e de Materiais


    The API 5L X70 steel is used in high-pressure gas transmission pipelines. Because of this, knowledge of presence of residual stress and their magnitude is important to assess the material integrity in service. For the pipeline manufacturing, tubes need to be curved which is often made using the hot induction bending process. This process can introduce different residual stress depending of tube position. For this research, in order to evaluate the residual stress, was used an API 5L X70 tube that was previously curved by hot induction process. Samples were taken from the extrados, intrados, neutral line and straight section of the curved tube. Residual stresses were studied by two conventional methods: X-Ray Diffraction (XRD) and Hole-Drilling, which are destructive and non-destructive methods, respectively, in order to assess their qualitative responses. Each of these methods presents particular methodologies in sample preparation and material analysis, but also they differ in factors such time consumption and cost of the analysis. The qualitative responses obtained by the two different methods were comparable and satisfactory and pointed out the existence of a compressive residual stress state in steel pipe. (author)

  7. A Plug-and-Play Duct System Evaluation

    Beach, Robert [IBACOS, Inc., Pittsburgh, PA (United States); Dickson, Bruce [IBACOS, Inc., Pittsburgh, PA (United States); Grisolia, Anthony [IBACOS, Inc., Pittsburgh, PA (United States); Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States); Rapport, Ari [IBACOS, Inc., Pittsburgh, PA (United States)


    This report describes an air distribution system composed of a series of uniformly-sized ducts that terminate in rooms throughout the home and return to a central manifold, similar in fashion to a “home-run” cross-linked polyethylene plumbing system. With a well-designed manifold, each duct receives an equal static pressure potential for airflow from the air handling unit, and the number of needed ducts for each room are simply attached to fittings located on the manifold; in this sense, the system is plug-and-play (PnP). As indicated, all ducts in the PnP system are identical in size and small enough to fit in the ceiling and wall cavities of a house (i.e., less than 3.5-in. outer diameter). These ducts are also more appropriately sized for the lower airflow requirements of modern, energy-efficient homes; therefore, the velocity of the air moving through the duct is between that of conventional duct systems (approximately 700 ft/min) and high-velocity systems (more than 1,500 ft/min) on the market today. The PnP duct system uses semi-rigid plastic pipes, which have a smooth inner wall and are straightforward to install correctly, resulting in a system that has minimal air leakage. However, plastic ducts are currently not accepted by code for use in residential buildings; therefore, the project team considered other duct materials for the system that are currently accepted by code, such as small-diameter, wirehelix, flexible ductwork.

  8. A Plug-and-Play Duct System Evaluation

    R. Beach, B. Dickson, A. Grisolia, A. Poerschke, A. Rapport


    This report describes an air distribution system composed of a series of uniformly-sized ducts that terminate in rooms throughout the home and return to a central manifold, similar in fashion to a “home-run” cross-linked polyethylene plumbing system. With a well-designed manifold, each duct receives an equal static pressure potential for airflow from the air handling unit, and the number of needed ducts for each room are simply attached to fittings located on the manifold; in this sense, the system is plug-and-play (PnP). As indicated, all ducts in the PnP system are identical in size and small enough to fit in the ceiling and wall cavities of a house (i.e., less than 3.5-in. outer diameter). These ducts are also more appropriately sized for the lower airflow requirements of modern, energy-efficient homes; therefore, the velocity of the air moving through the duct is between that of conventional duct systems (approximately 700 ft/min) and high-velocity systems (more than 1,500 ft/min) on the market today. The PnP duct system uses semi-rigid plastic pipes, which have a smooth inner wall and are straightforward to install correctly, resulting in a system that has minimal air leakage. However, plastic ducts are currently not accepted by code for use in residential buildings; therefore, the project team considered other duct materials for the system that are currently accepted by code, such as small-diameter, wirehelix, flexible ductwork.

  9. Flow Investigation inside A Curved Square Duct

    Dipyaman Gangopadhyay


    Full Text Available This paper presents the results of an experimental work with measurement of wall static pressure of 90°C shaped Curved duct. The test duct is made up of transparent perspex sheets to facilitate the flow visualization study. The duct has an inlet to exit area ratio of 1.0 with centerline distance of 750 mm. The inlet aspect ratio of the test duct has been fixed at 1.0. The velocities for the proposed investigations are to be measured by using a Pitot tube.Wall pressures are measured with the help of an inclinedmanometer with the inclination of 35°. The manometer had two tubes emanating from it: one left open to the atmosphere and the other connected to the steel pipes attached to the four walls of the curved duct. The difference in the readings helped us calculate the static pressure and thereby the normalized pressure. Wall pressure distribution along the curved and parallel walls of the duct at 0°, 22.5°, 45°, 67.5° and 90° measuring sections was measured. All the experimental data has been processed by an Intel i3 CPU, 3 GB RAM PC and analyzed to give the distribution of static pressure in the square duct.The main purpose of this investigation is to show the development of secondary flow which happens when the flow takes place through the bend in the curvature. This secondary flow arises as a result of a centrifugal force acting when the flow moves through the bend. The investigation is carried out at three different velocities 20 m/s, 40 m/s and 60 m/s. The distribution of normalized pressure which is the ratio of static pressure to the dynamic pressure is mapped and shown in the form of contours by using the software package SURFER.The trend of wall static pressure development on the walls of C shaped duct shows that as the flow proceeds towards the curvature, there exists a high pressure gradient between the outside face and inside face due the centrifugal force acting along the curvature. This shows the bulk shifting of flow towards

  10. Fracture mechanics parameters of multilayer pipes

    Šestáková L.


    Full Text Available Multilayer pipes consisting of different materials are frequently used in praxis because of partial improvement of the properties of pipe systems. To estimate lifetime of these pipes the basic fracture parameters have to be determined. In this work finite element calculations are applied in order to estimate the stress intensity factor K and T-stress values for a new type of non-homogenous C-shape specimen. The application of calculated K and T values to laboratory estimation of fracture toughness and its transferability to real pipe system is discussed.

  11. 大型压缩机组柔性结构应力管道安装%Installation of stress piping with flexible construction for large compressor train



    To realize a safe reliable operation of petrochemical process units, the installation quality of large compressor trains must be ensured. The critical aspect is to solve the stress problems in installation of piping system of compressors and ensure the concentricity of compressor train and shaft system. In the fabrication of the flexible thermal power piping system of a large GB-201 compressor train, the materials are precisely cut and mechanically processed after strictly measurement at the site. In assembling process, the turbine base is examined by dial indicator for displacement. After assembly, difference in concentricity of flanges is measured with feeler and micrometer and the height of spring support and piping position are adjusted to meet difference requirement. At the same time, monitoring is greatly enhanced to eliminate the stress on the compressor train in installation. The practice of the above measures has ensured the preciseness of installation dimensions of piping system and stressless installation of flexible thermal piping system of compressor train. The large compressor train is successfully commissioned at the first try and ethylene cracking unit is operating smoothly.%为实现石油化工装置安全、平稳运行,必须确保其核心部位大型压缩机组的安装质量,其关键是懈决大型压缩机组管道安装的应力问题,确保机组同心度及轴系同心度.针对GB-201大型压缩机组双进汽设计的柔性热力管道系统,预制过程中需在严格现场实测后进行精确下料和机械加工,组装过程中在透平基座布置百分表进行位移监测,组装完成后利用塞尺和千分尺对法兰同心度进行偏差测量并通过调整弹簧支架高度和管道位置保证偏差符合要求,并通过安装过程中加大监控力度消除对机组产生的应力.结果表明:以上方法的实施确保了管道系统安装尺寸的精确,有效保证了压缩机组柔性热力管道系统无应力安

  12. Piping Connector


    In Stennis Space Center's Component Test Facility, piping lines carry rocket propellants and high pressure cryogenic fuels. When the lines are chilled to a pretest temperature of 400 degrees below zero, ordinary piping connectors can leak. Under contract to Stennis, Reflange, Inc. developed the T-Con connector, which included a secondary seal that tolerates severe temperature change. Because of the limited need for the large and expensive T-Con product, Reflange also developed the less costly E-Con, a smaller more compact design with the same technical advantages as the T-Con.

  13. Research on Test Methods for Pre-stressed Pipe Grouting Quality%预应力管道压浆质量检测方法的研究

    向勇; 张梦龙; 屈建强; 张麟


    通过比较的方法,介绍了目前国内外最常用的检测预应力管道压浆质量的方法,分别有冲击回波法、探地雷达法、超声波法、超声波层析成像法等几种检测方法。总结了这几种方法在工程应用上的特点,并根据国内外的研究应用结果,推荐冲击回波法为预应力管道压浆质量的检测方法。%This article,through the comparison,introduced the present domestic and foreign most commonly used pre-stressed pipe grouting quality test methods,including several detection methods such as impact echo method,ultrasonic method,ground penetrating radar method,ultrasonic tomographic imaging method,summaried the characteristics of these methods in engineering application,and recommended that impact echo method is the test method for pre-stressed grouting quality according to its application and research results at home and abroad.

  14. Curved-Duct

    Je Hyun Baekt


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

  15. Fatigue analysis of aluminum drill pipes

    João Carlos Ribeiro Plácido


    Full Text Available An experimental program was performed to investigate the fundamental fatigue mechanisms of aluminum drill pipes. Initially, the fatigue properties were determined through small-scale tests performed in an optic-mechanical fatigue apparatus. Additionally, full-scale fatigue tests were carried out with three aluminum drill pipe specimens under combined loading of cyclic bending and constant axial tension. Finally, a finite element model was developed to simulate the stress field along the aluminum drill pipe during the fatigue tests and to estimate the stress concentration factors inside the tool joints. By this way, it was possible to estimate the stress values in regions not monitored during the fatigue tests.

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

    Kowal, Justyna Magdalena; Yegutkin, G.G.; Novak, Ivana


    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...

  17. Mechanical properties of the porcine bile duct wall

    Andersen Helle


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

  18. Plastic pipe systems failure investigation and diagnosis

    Farshad, Mehdi


    Industrial and domestic piping is increasingly made from various plastics and composites, and these materials withstand heavy use over long periods. They are, however, affected by environmental and other factors over time and can degrade, causing major problems within piping systems. Farshad's book deals with why plastic pipes and systems fail, and with how to investigate and diagnose such failures. Pipes may buckle, fracture, change in dimensions and colour, blister and delaminate, corrode through stress, be abraded and obstructed: all these cause problems and lead to loss of efficient operat

  19. 49 CFR 195.207 - Transportation of pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transportation of pipe. 195.207 Section 195.207... PIPELINE Construction § 195.207 Transportation of pipe. (a) Railroad. In a pipeline operated at a hoop stress of 20 percent or more of SMYS, an operator may not use pipe having an outer diameter to wall...

  20. Particle deposition in ventilation ducts

    Sippola, Mark Raymond [Univ. of California, Berkeley, CA (United States)


    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 μm 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 the

  1. Particle deposition in ventilation ducts

    Sippola, Mark R.


    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

  2. What Is Bile Duct Cancer?

    ... the liver. Types of bile duct cancer by cell type Bile duct cancers can also be divided ... Our Volunteers More ACS Sites Bookstore Shop Cancer Atlas Press Room Cancer Statistics Center Volunteer Learning Center ...

  3. Gallbladder and Bile Duct Disorders

    ... Disorders Overview of Gallbladder and Bile Duct Disorders Cholecystitis Gallstones Biliary Pain Without Gallstones Narrowing of the ... ducts are blocked, the gallbladder may become inflamed ( cholecystitis ). Biliary pain without gallstones (acalculous biliary pain) can ...



    Stresses and deformation states of pipe bending are investigated under loading or unloading with various pipe materials, size, bending radius and deformation temperature. A theorem of springback of large diameter pipe bending is presented. The experiments are carried out with pipe materials of 20, 10CrMo910 and 12Cr1MoV steel. Results of computations are in good agreement with experiments.

  5. Malignant tumors of Stensen's duct.

    Steiner, M; Gould, A R; Miller, R L; Johnson, J A


    A rare case of squamous cell carcinoma arising in Stensen's duct is reported. The literature concerning malignant neoplasia originating in this site is reviewed, with attention given to the histopathologic diversity of neoplasms occurring in the duct, criteria for determination of origin in the duct, and outcomes of therapy.

  6. Isolated Pancreatic Uncinate Duct IPMN.

    Maker, Ajay V; Maker, Vijay K


    The ventral pancreas originally forms as an evagination of the common bile duct at 32 days gestation and its duct, the uncinate duct, eventually rotates with the ventral anlage to join the dorsal pancreas and fuse with the main pancreatic duct. Thus, though often considered a "branch" duct of the pancreas, embryologically, the uncinate duct is the "main" pancreatic duct of the ventral pancreas. This concept is not fully addressed in the current definitions of intraductal papillary mucinous neoplasms of the pancreas (IPMN) where international consensus guidelines consider the main-duct IPMN as high risk for malignancy and most small branch-duct IPMN as low risk for malignancy. Thus, it is important to recognize that isolated uncinate-duct IPMN can occur and, based on its embryologic origin and increased association with high-grade dysplasia and invasive cancer, may be managed conceptually as a main duct type of disease rather than a branch duct until better biomarkers of malignancy are discovered. The images provide an example of this unique disease process.

  7. Heat pipes

    Dunn, Peter D


    A comprehensive, up-to-date coverage of the theory, design and manufacture of heat pipes and their applications. This latest edition has been thoroughly revised, up-dated and expanded to give an in-depth coverage of the new developments in the field. Significant new material has been added to all the chapters and the applications section has been totally rewritten to ensure that topical and important applications are appropriately emphasised. The bibliography has been considerably enlarged to incorporate much valuable new information. Thus readers of the previous edition, which has established

  8. Simulation of three-dimensional stress field in welding process of high-frequency welded pipe%高频焊管在焊接过程中三维应力场的模拟

    何世权; 刘飞; 徐德怀; 钟辉


    In the production process of high-frequency welded pipe, the elimination of the high-frequency welding residual stresses caused by high-frequency welding is an important working operation. A knowledge of the residual stress of the welded pipe in advance of welding is significant for the residual stress elimination. Making use of APDL language embedded in ANSYS, a finite element model of high-frequency welded pipe was established. Then the linear thermal source model was used to conduct the computation.Meantime, the thermal boundary conditions and the physical structure of the constraints of this finite element model were also taken into account, so that the three-dimensional stress field and displacement field could be obtained for the high-frequency pipe welding process. From the analysis of result of the finite element simulation, the stress field and displacement field of the welded pipe could be theoretically obtained in advance of the stress relief process.%在高频焊管生产过程中,消除因高频焊接造成的焊管残余应力是一项重要的工序,预先得出焊管残余应力场对于消除焊管残余应力具有指导意义.利用ANSYS参数化语言APDL,建立高频焊管的有限元模型,采用高频焊接线热源模型进行计算,同时考虑高频焊管有限元模型的热边界条件及物理结构约束,从而获得高频焊管在焊接过程中三维应力场及位移场.通过对有限元模拟结果的分析,可以从理论上得出焊管在进行消除残余应力工序前的应力和位移分布.

  9. HPFRCC - Extruded Pipes

    Stang, Henrik; Pedersen, Carsten


    as well as structural design. Material development was carried out considering both processing requirements as well as mechanical properties of the hardened material. A micro-mechanical model for the non-linear material behavior of the hardened material based on the stress-crack width or the $\\sigma...... itself. The structural modeling of the pipe was done making direct use of the $\\sigma-w$ material characterization. The processing technique developed is a novel type of extrusion combiningease of material mixing and few requirements for material pre-processingwith a high degree of accuracy and stability...

  10. Short-Term Nose-Only Water-Pipe (Shisha Smoking Exposure Accelerates Coagulation and Causes Cardiac Inflammation and Oxidative Stress in Mice

    Abderrahim Nemmar


    Full Text Available Background/Aim: Water-pipe smoking (WPS has acquired worldwide popularity, and is disseminating particularly rapidly in Europe and North America. However, little is known about the short-term cardiovascular effects of WPS. Methods: Presently, we assessed the short-term cardiovascular effects of nose-only exposure to mainstream WPS in BALB/c mice for 30 min/day for 5 consecutive days. Control mice were exposed to air. At the end of the exposure period, several cardiovascular endpoints were measured. Results: WPS did not affect the number of leukocytes and the plasma concentrations of C-reactive protein, tumor necrosis factor α (TNFα and interleukin-6 (IL-6. Likewise, plasma levels of lipid peroxidation (LPO, reduced glutathione (GSH and catalase were not affected by WPS. By contrast, WPS aggravated in vivo thrombosis by shortening the thrombotic occlusion time in pial arterioles and venules. The number of circulating platelets was reduced by WPS suggesting the occurrence of platelet aggregation in vivo. Elevated concentrations of fibrinogen and plasminogen activator inhibitor-1 were seen after the exposure to WPS. Blood samples taken from mice exposed to WPS and exposed to adenosine diphosphate showed more platelet aggregation. The heart concentrations of IL-6 and TNFα were augmented by WPS. Likewise, heart levels of LPO, reactive oxygen species and the antioxidants catalase and GSH were increased by WPS. However, the systolic blood pressure and heart rate were not affected by WPS. Conclusion: It can be concluded that short-term exposure to WPS exerts procoagulatory effects and induce cardiac inflammation and oxidative stress. At the time point investigated, there was no evidence for blood inflammation or oxidative stress.

  11. Cornice Duct System

    Wayne Place; Chuck Ladd


    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.

  12. Piping support system for liquid-metal fast-breeder reactor

    Brussalis, Jr., William G.


    A pipe support consisting of a rigid link pivotally attached to a pipe and an anchor, adapted to generate stress or strain in the link and pipe due to pipe thermal movement, which stress or strain can oppose further pipe movement and generally provides pipe support. The pipe support can be used in multiple combinations with other pipe supports to form a support system. This support system is most useful in applications in which the pipe is normally operated at a constant elevated or depressed temperature such that desired stress or strain can be planned in advance of pipe and support installation. The support system is therefore especially useful in steam stations and in refrigeration equipment.

  13. 14 CFR 25.1103 - Induction system ducts and air duct systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction system ducts and air duct systems....1103 Induction system ducts and air duct systems. (a) Each induction system duct upstream of the first... auxiliary power unit bleed air duct systems, no hazard may result if a duct failure occurs at any...


    Huan-RueiShiu; Feng-ChuOu; Sih-LiChen


    A new 3C duct design method is proposed for designing a high quality, energy-efficiency cost-effective air duct system. It not only considers the demand of volume flow rate, but also takes into consideration a number of issues including system pressure balance, noise, vibration, space limitation and total system cost. This new method comprises three major calculation procedures:initial computer-aided design (CAD), computer-aided simulation (CAS) and correction processes (CP). An example is presented in this study to understand the characteristics of 3C method. It shows that 3C duct design method provides a simple computation procedure for an optimum air duct system. It also shortens the design schedule, prevents human calculation errors, and reduces the dependence on designer experience. In addition to apply in a new duct system design, 3C duct design method is also a powerful design tool for the expansion of an existing duct system.

  15. J-Integral Estimate for Circumferential Cracked Pipes Under Primary and Secondary Stress in R, RBC-MR A

    Nam, Hyun Suk; Oh, Chang Young; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of)


    This paper provides a comparison of the J-integral estimation method under combined primary and secondary stress in the R, RBC-MR A code. The comparisons of each code are based on finite element analysis using Abacus with regard to the crack shape, crack depth, and magnitude of secondary load. The estimate of the R code is conservative near L{sub r} = 1, and that of the RBC-MR A code is conservative near L{sub r} = 0. As a result, this paper proposes a modified method of J-integral estimation in the R, RCC{sub M}R A code. The J-integral using the modified method corresponds to the finite element analysis result.

  16. Salivary duct carcinoma

    Breinholt, Helle; Elhakim, Mohammad Talal; Godballe, Christian;


    1990 to 2005 were identified. Histological slides were reviewed, and data concerning demographics, tumour site, clinical stage, treatment profiles and follow-up were retrieved. Survival estimates and prognostic factors were evaluated by comparing Kaplan-Meier plots using the Mantel-Haenszel log......-rank test. RESULTS: Salivary duct carcinoma showed an incidence of 0.04/100.000 inhabitants/year. Distant recurrence was seen in 52% of patients. Five-year overall survival, disease-specific survival and recurrence-free survival were 32%, 42% and 35%, respectively. Univariate analyses suggested that overall...... stage (III/IV) and vascular invasion have a negative impact on all survival measures. Involved resection margins correlated with a poorer overall survival and disease-specific survival, whereas adjuvant radiotherapy improved overall survival and recurrence-free survival. CONCLUSIONS: Salivary duct...

  17. Fundamentals of piping design

    Smith, Peter


    Written for the piping engineer and designer in the field, this two-part series helps to fill a void in piping literature,since the Rip Weaver books of the '90s were taken out of print at the advent of the Computer Aid Design(CAD) era. Technology may have changed, however the fundamentals of piping rules still apply in the digitalrepresentation of process piping systems. The Fundamentals of Piping Design is an introduction to the designof piping systems, various processes and the layout of pipe work connecting the major items of equipment forthe new hire, the engineering student and the vetera



    In this paper, using an orthogonal curvilinear coordinate system and solving the complete N-S equations, we analyzed the flow in a helical elliptical duct by the perturbation method. The first-order solutions of the stream function Ψ, axial velocity w and the velocity of secondary flow (u, v) were obtained. The effects of torsion, curvature and the axial pressure gradient on the secondary flow were discussed in detail. The study indicates that the torsion has first-order effect on the secondary flow in a helical elliptical pipe, the secondary flow is dominated by torsion when the axial pressure gradient is small and for increasing gradient the secondary flow is eventually dominated by the effect due to curvature. The fact that the torsion has no effect on fluid flow in a helical pipe with a circular cross section was also confirmed. The most important conclusion is that the flow in a helical elliptical pipe to the first-order can be obtained as a combination of the flow in a toroidal pipe and the flow in a twisted pipe.


    黄孟才; 顾忠; 沈俊; 唐复勇


    The paper deals with nonlinear elasticity of blood arterial duct, in which the artery is modeled to bea locally triclinic, transverse isotropic, incorapressible, axisymmetric and thickwalled tube with large deformations, The nonlinear coustitutive relationship of arterial tissues is based on the theorv of Green and Adkins. A nonlinear strain energy density function is introduced for nonlinear stress-strain relationship of second order, in which the coefficient of each term is expressed by means of a Lame’s constant, The elasticity constants are nqcessary to describe such a uonlinear finite strain etastieity of the second order, These constants are determined by means of the stress-strain increment theory.

  20. Asymptomatic common bile duct stones.

    Rosseland, A R; Glomsaker, T B


    Patients with asymptomatic bile duct stones exhibit typical signs, such as elevated liver function tests, dilated bile ducts on ultrasound, a history of jaundice, or pancreatitis. The incidence of asymptomatic bile duct stones is about 10%, but up to 2% of patients show no signs of the disease. Bile duct stones can be diagnosed by using clinical judgement, scoring systems, or discriminant function tests. Which diagnostic modality is most reliable, cost-effective and safe, varies with different hospitals. Which therapy is most effective, safe and the cheapest also varies with different departments, but in the future an increasing number of departments will use the one-stage laparoscopic approach.

  1. Noise reduction of spiral ducts.

    Lapka, Wojciech; Cempel, Czesław


    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. Gallbladder and bile duct


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

  3. Stopping duct quacks: Longevity of residential duct sealants

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


    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 shown that these seals tend to fail over time periods ranging from days to years. We have used several test methods over the last few years to evaluate the longevity of duct sealants when subjected to temperatures and pressures representative of those found in the field. Traditional cloth duct tapes have been found to significantly under-perform other sealants and have been banned from receiving duct tightness credits in California's energy code (California Energy Commission 1998). Our accelerated testing apparatus has been redesigned since its first usage for improved performance. The methodology is currently under consideration by the American Society for Testing and Materials (ASTM) as a potential new test method. This report will summarize the set of measurements to date, review the status of the test apparatus and test method, and summarize the applications of these results to codes and standards.

  4. Reusable pipe flange covers

    Holden, James Elliott (Simpsonville, SC); Perez, Julieta (Houston, TX)


    A molded, flexible pipe flange cover for temporarily covering a pipe flange and a pipe opening includes a substantially round center portion having a peripheral skirt portion depending from the center portion, the center portion adapted to engage a front side of the pipe flange and to seal the pipe opening. The peripheral skirt portion is formed to include a plurality of circumferentially spaced tabs, wherein free ends of the flexible tabs are formed with respective through passages adapted to receive a drawstring for pulling the tabs together on a back side of the pipe flange.

  5. Pipe drafting and design

    Parisher, Roy A; Parisher


    Pipe designers and drafters provide thousands of piping drawings used in the layout of industrial and other facilities. The layouts must comply with safety codes, government standards, client specifications, budget, and start-up date. Pipe Drafting and Design, Second Edition provides step-by-step instructions to walk pipe designers and drafters and students in Engineering Design Graphics and Engineering Technology through the creation of piping arrangement and isometric drawings using symbols for fittings, flanges, valves, and mechanical equipment. The book is appropriate primarily for pipe

  6. 预应力混凝土后张梁孔道摩阻损失试验分析%Research on the Experiment Test of Frictional Resistance Loss in Post-tensioning Pre-stressed Concrete Beam Pipe



    The loss of frictional resistance in post -tesioning pre-stressed concrete beam pipe is a big problem during the construction of post-tesioning pre-stressed concrete bridge. The test of frictional resistance loss is important to the quality security and persistence of bridge construction. The formula of beam pipe frictional resistance loss co-effi-cient was calculated by least square method. This formula was applied on the xianhu bridge construction ,then the project of frictional resistance loss test of beam pipe was proposed to reduce the loss of pre-stress and analyze the practical data in the xianhu bridge construction.%在后张法预应力混凝土桥梁结构的建设中,预应力孔道摩阻损失问题十分突出。孔道摩阻测试对确保桥梁结构的施工质量、安全性和耐久性有着重要意义。以仙葫大桥为例,在公式分析的基础上结合最小二乘法原理,推导出孔道摩阻参数的计算公式,为减少预应力损失,提出了孔道摩阻试验检测的方案,同时对该桥现场测试数据进行了计算和分析。研究结果可为同类施工提供参考。

  7. Propagation of sound waves in ducts

    Jacobsen, Finn


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

  8. Surgery for Bile Duct (Cholangiocarcinoma) Cancer

    ... Situation Bile Duct Cancer Treating Bile Duct Cancer Surgery for Bile Duct Cancer There are 2 general ... also help plan the operation to remove it. Surgery for resectable cancers For resectable cancers, the type ...

  9. Avaliação das tensões residuais em tubos de pequeno diâmetro soldados pelo processo TIG orbital Residual stress evaluation in small diameter pipes welded using orbital TIG process

    George Luiz Gomes de Oliveira


    Full Text Available O objetivo desse trabalho é avaliar o efeito da soldagem TIG orbital sobre o nível de tensões residuais da junta, sobre a microestrutura resultante e sobre o aspecto superficial do cordão de solda, considerando os efeitos da energia de soldagem, do número de passes e do tipo de pulsação (corrente e rotação em tubos de pequeno diâmetro e contribuir para a análise de decisões de se aplicar ou não testes hidrostáticos ou TTPS. Os corpos de prova soldados com diferentes níveis de energia, pulsação e número de passes foram submetidos à medição de tensões residuais em um difratômetro de Raios-X. As amostras também foram submetidas a análises metalográficas. Conclui-se que as tensões residuais na superfície externa dos tubos são de caráter compressivo. O nível de tensões residuais nos tubos cai com o aumento da energia de soldagem e é menor para tubos soldados utilizando pulsação do que com os soldados sem pulsação e, para esse trabalho, não foi influenciado substancialmente pelo número de passes. As amostras analisadas apresentaram microestruturas convencionais para o aço empregado.This work aims in evaluate the effect of orbital TIG welding on the joint's residual stress level, the final microstructure and the superficial aspect of the weld filet, observing the welding energy, number of passes and the type of pulsation effects in small diameter pipes. The test specimens were welded with different energy, pulsation and number of passes levels and after that it were submitted to residual stress measurement in a X-Ray diffractometer, samples were extracted from the test specimens and it were submitted to metallographic analysis. The ending of this work is that: residual stress in the pipes outer surface are compressive, residual stress level in pipes goes down with increasing welding energy, it is smaller for pipes welded with pulsation and in this work it were not effectively influenced by number of passes

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

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


    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

  11. 压水堆主管道上充管嘴弹塑性应力分析%Elastoplastic Stress Analysis for Charging Nozzle of PWR Primary Piping

    艾红雷; 郑斌; 卢喜丰; 王新军


    压水堆主管道上充管嘴在核电厂运行期间需经受严厉的冷热流体交互流动产生的循环热载荷,将对上充管嘴的结构完整性产生重要的影响.上充管嘴弹性应力分析证明了结构不会出现弹性失稳、塑性失稳以及疲劳破坏等现象,但部分分析截面一次加二次应力强度范围超过了规范限值.针对弹性分析部分结果不满足规范限值的情况,对上充管嘴进行了循环弹塑性分析,结果表明,上充管嘴结构在循环载荷作用下出现了明显的塑性安定现象,并且经历所分析的循环载荷后,其结构的累积应变不会对结构抗塑性失稳能力和抗疲劳破坏能力产生显著的影响.上充管嘴抗快断分析表明,其结构具备良好的抗快断性能.%The severe cyclical thermal loadings which generated by the interaction flow of hot and cold flu-id are subjected to the charging nozzle of PWR primary piping during the operation of nuclear power plants.The loadings have significant impact on the structural integrity.The types of damage( elastic insta-bility,plastic instability,fatigue and so on) do not occur for the nozzle is proved by elastic analysis.For some analysis sections,the range of primary plus secondary stresses cannot be validated and the cyclical elastoplastic analysis is used.The results show that the behavior of plastic accommodation occurred under the cyclical loadings and the cumulative strain induced by repeated loads do not diminish the capacity to prevent the damage of plastic instability and fatigue.The results of resistance to fast fracture analysis show that the nozzle has a good ability of resistance to fast fracture.

  12. Propagation of sound waves in ducts

    Jacobsen, Finn


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

  13. Sound propagation through nonuniform ducts

    Nayfeh, A. H.


    Methods of determining the transmission and attenuation of sound propagating in nonuniform ducts with and without mean flows are discussed. The approaches reviewed include purely numerical techniques, quasi-one-dimensional approximations, solutions for slowly varying cross sections, solutions for weak wall undulations, approximation of the duct by a series of stepped uniform cross sections, variational methods and solutions for the mode envelopes.

  14. Intrahepatic Transposition of Bile Ducts

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


    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


    The installation of the central section of the beam pipe into the heart of the  CMS was completed by 23 April. All the beam pipe elements have been successfully vacuum-tested and the bakeout started.  

  16. Laparoscopic common bile duct exploration.

    Stoker, M E; Leveillee, R J; McCann, J C; Maini, B S


    Operative common bile duct exploration, performed in conjunction with cholecystectomy, has been considered the treatment of choice for choledocholithiasis in the presence of an intact gallbladder. With the advent of laparoscopic cholecystectomy, the management of common bile duct stones has been affected. More emphasis is being placed on endoscopic sphincterotomy and options other than operative common duct exploration. Because of this increasing demand, we have developed a new technique for laparoscopic common bile duct exploration performed in the same operative setting as laparoscopic cholecystectomy. A series of five patients who successfully underwent common bile duct exploration, flexible choledochoscopy with stone extraction, and T-tube drainage, all using laparoscopic technique, is reported. Mean postoperative length of hospital stay was 4.6 days. Outpatient T-tube cholangiography was performed in all cases and revealed normal ductal anatomy with no retained stones. Follow-up ranged from 6 weeks to 4 months, and all patients were asymptomatic and had normal liver function tests.

  17. Ascariasis of the pancreatic duct.

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


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

  18. Burst limit state reliability for fiber-wrapped steel pipe

    Dann, Markus R. [University of Calgary (Canada); Maes, Marc A. [Blade Energy Partners Ltd. (Canada); Salama, Mamdouh M. [ConocoPhillips Company (United States)


    In the oil and gas sector, due to the increase in demand, pipeline projects are being developed in remote areas with harsh environments. High strength steel pipelines have been developed but due to their high cost and to low production capacity, the focus is now on dry fiber augmented steel technology pipelines (FAST-Pipe). The aim of this paper is to present a probabilistic mechanical burst limit state for such fiber wrapped pipelines. This model has been developed based on a large strain Cauchy stress formulation and has been used to perform a reliability comparison between an X80 pipe and an X70 FAST-Pipe. Results showed that the FAST-Pipe has more uncertainties than the high strength steel pipe and thus lower factors should be used in their design. This paper provided a probabilistic limit state model which can be used for both steel pipes and FAST-Pipe.

  19. Novel Approach to Bile Duct Damage in Primary Biliary Cirrhosis: Participation of Cellular Senescence and Autophagy

    Motoko Sasaki


    Full Text Available Primary biliary cirrhosis (PBC is characterized by antimitochondrial autoantibodies (AMAs in patients' sera and histologically by chronic nonsuppurative destructive cholangitis in small bile ducts, eventually followed by extensive bile duct loss and biliary cirrhosis. The autoimmune-mediated pathogenesis of bile duct lesions, including the significance of AMAs, triggers of the autoimmune process, and so on remain unclear. We have reported that cellular senescence in biliary epithelial cells (BECs may be involved in bile duct lesions and that autophagy may precede the process of biliary epithelial senescence in PBC. Interestingly, BECs in damaged bile ducts show characteristicsof cellular senescence and autophagy in PBC. A suspected causative factor of biliary epithelial senescence is oxidative stress. Furthermore, senescent BECs may modulate the microenvironment around bile ducts by expressing various chemokines and cytokines called senescence-associated secretory phenotypes and contribute to the pathogenesis in PBC.

  20. 49 CFR 192.315 - Wrinkle bends in steel pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel pipe to be operated at a pressure that produces a hoop stress of 30 percent, or more, of SMYS. (b) Each...

  1. 基于ANSYS软件三通管应力分布特性分析%The characteristics of stress distribution of three-way pipe based on ANSYS software



    应用有限元分析软件ANSYS10.0,对三通管应力进行计算分析,获得了内压作用下三通管的应力分布特性,在工程上,可以解决设备开孔部位是否需要加强的问题。%By the finite element analysis software ANSYS10.0, the stress of three-way pipe was calculated and the stress distribution was obtained under the action of internal pressure. It can solve the problem whether the hole position of the equipment needs to be strengthened in the project.

  2. PMR Graphite Engine Duct Development

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


    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.

  3. Study of fatigue behavior of longitudinal welded pipes

    Simion, P.; Dia, V.; Istrate, B.; Hrituleac, G.; Hrituleac, I.; Munteanu, C.


    During transport and storage of the various fluids, welded pipes are subjected to cyclic loading due to pressure fluctuations that often exceed the prescribed values for normal operation. These cyclic loading can significantly reduce the life of the pipes; as a result the design should be based on the fatigue strength not only on static resistance. In general the fatigue strength of pipes is dependent by strength, pipe geometry and surface quality. In case of the electric longitudinal welded pipes, the fatigue strength is significantly limited by concentration of residual stress and the size of existing defects in the weld seam. This paper presents the fatigue behaviour of the electric welded pipes by high frequency, under conditions that simulate real operating conditions pipes. Fatigue testing was performed on welded pipes made of micro alloyed carbon steels. Some of these pipes were previously subjected to a heat treatment of normalization, in order to also determine the influence of heat treatment on the fatigue strength of welded pipes. To determine and correlate the different factors affecting the fatigue strength, welded pipes were also subjected to various tests: tensile tests, impact tests, measurement of micro hardness, microstructural analysis by optical microscopy and scanning electron microscopy.

  4. Impedance modelling of pipes

    Creasy, M. Austin


    Impedance models of pipes can be used to estimate resonant frequencies of standing waves and model acoustic pressure of closed and open ended pipes. Modelling a pipe with impedance methods allows additional variations to the pipe to be included in the overall model as a system. Therefore an actuator can be attached and used to drive the system and the impedance model is able to include the dynamics of the actuator. Exciting the pipe system with a chirp signal allows resonant frequencies to be measured in both the time and frequency domain. The measurements in the time domain are beneficial for introducing undergraduates to resonances without needing an understanding of fast Fourier transforms. This paper also discusses resonant frequencies in open ended pipes and how numerous texts incorrectly approximate the resonant frequencies for this specific pipe system.

  5. Ligadura de ducto biliar como modelo de estudo da síndrome hepatopulmonar e estresse oxidativo Common bile duct ligation as a model of hepatopulmonary syndrome and oxidative stress

    Juliana Tieppo


    hepatopulmonary syndrome is characterized by hepatic dysfunction and presence of dilated pulmonary vessels, with alterations in air diffusion that can be demonstrated in the experimental model of common bile duct ligation. AIM: To evaluate the oxidative stress in pulmonary tissue of cirrhotic rats with common bile duct ligation. MATERIAL/METHODS: We used 12 male Wistar rats weighing between 200-300 g divided in two groups: control (Co = 6 and cirrhotic (Ci = 6. We evaluated aminotransferases, arterial gasometry, lipoperoxidation and chemoluminescence, and antioxidant enzymatic activity with superoxide dismutase. The tissues analyzed for hepatopulmonary syndrome were cirrhotic liver and lung. RESULTS: The animals with common bile duct ligation showed alterations in the following aminotransferases: aspartate aminotransferase, Co = 105.3 ± 43/Ci = 500.5 ± 90.3, alanine aminotransferase, Co = 78.75 ± 37.7/Ci = 162.75 ± 35.4, and alkaline phosphatase, Co = 160 ± 20.45/Ci = 373 ± 45.44. The lipoperoxidation and the antioxidant response had significant differences between the groups when evaluated in lung (lipoperoxidation Co = 0.87 ± 0.3/Ci = 2.01 ± 0.9, chemoluminescence Co = 16008.41 ± 1171.45/Ci = 20250.36 ± 827.82 superoxide dismutase Co = 6.66 ± 1.34/Ci = 16.06 ± 2.67. CONCLUSIONS: Our results suggest that in this experimental model of cirrhosis using common bile duct ligation, there is an increase in lipoperoxidation in pulmonary tissue as well as an increase in superoxide dismutase's antioxidant activity, suggesting a pulmonary injury caused by secondary biliary cirrhosis.

  6. Optimizing the Treatment of Acute Duct-Destructive Pancreatitis

    Zhakiev, Bazylbek S.; Karsakbayev, Uteugali G.; Kelimberdiev, Mersaid S.; ?uhamedgalieva, Bodagoz M.; K?nonenko, Aleksander F.


    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…

  7. 14 CFR 29.1103 - Induction systems ducts and air duct systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction systems ducts and air duct systems. 29.1103 Section 29.1103 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF....1103 Induction systems ducts and air duct systems. (a) Each induction system duct upstream of the...

  8. Migratory intralaryngeal thyroglossal duct cyst

    Karlatti Pradeep


    Full Text Available Intralaryngeal thyroglossal duct cysts are rare; a migrating one, rarer still. Such a case may be a cause for confusion and it is important to understand this entity and its typical findings.

  9. Application of LBB to a nozzle-pipe interface

    Yu, Y.J.; Sohn, G.H.; Kim, Y.J. [and others


    Typical LBB (Leak-Before-Break) analysis is performed for the highest stress location for each different type of material in the high energy pipe line. In most cases, the highest stress occurs at the nozzle and pipe interface location at the terminal end. The standard finite element analysis approach to calculate J-Integral values at the crack tip utilizes symmetry conditions when modeling near the nozzle as well as away from the nozzle region to minimize the model size and simplify the calculation of J-integral values at the crack tip. A factor of two is typically applied to the J-integral value to account for symmetric conditions. This simplified analysis can lead to conservative results especially for small diameter pipes where the asymmetry of the nozzle-pipe interface is ignored. The stiffness of the residual piping system and non-symmetries of geometry along with different material for the nozzle, safe end and pipe are usually omitted in current LBB methodology. In this paper, the effects of non-symmetries due to geometry and material at the pipe-nozzle interface are presented. Various LBB analyses are performed for a small diameter piping system to evaluate the effect a nozzle has on the J-integral calculation, crack opening area and crack stability. In addition, material differences between the nozzle and pipe are evaluated. Comparison is made between a pipe model and a nozzle-pipe interface model, and a LBB PED (Piping Evaluation Diagram) curve is developed to summarize the results for use by piping designers.




    Two variations on the tests for duct leakage currently embodied in ASHRAE Standard 152P (Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems) are presented. Procedures are derived for calculating supply and return duct leakage to/from outside using these new variations. Results of these tests are compared with the original ones in Standard 152P on the basis of data collected in three New York State homes.

  11. Duct Leakage Repeatability Testing

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


    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. Predictions for fatigue crack growth life of cracked pipes and pipe welds using RMS SIF approach and experimental validation

    Arora, Punit, E-mail: [Bhabha Atomic Research Centre, Department of Atomic Energy, Maharashtra, Mumbai 400 085 (India); Singh, P.K.; Bhasin, Vivek; Vaze, K.K.; Ghosh, A.K. [Bhabha Atomic Research Centre, Department of Atomic Energy, Maharashtra, Mumbai 400 085 (India); Pukazhendhi, D.M.; Gandhi, P.; Raghava, G. [Structural Engineering Research Centre, Chennai 600 113 (India)


    The objective of the present study is to understand the fatigue crack growth behavior in austenitic stainless steel pipes and pipe welds by carrying out analysis/predictions and experiments. The Paris law has been used for the prediction of fatigue crack growth life. To carry out the analysis, Paris constants have been determined for pipe (base) and pipe weld materials by using Compact Tension (CT) specimens machined from the actual pipe/pipe weld. Analyses have been carried out to predict the fatigue crack growth life of the austenitic stainless steel pipes/pipes welds having part through cracks on the outer surface. In the analyses, Stress Intensity Factors (K) have been evaluated through two different schemes. The first scheme considers the 'K' evaluations at two points of the crack front i.e. maximum crack depth and crack tip at the outer surface. The second scheme accounts for the area averaged root mean square stress intensity factor (K{sub RMS}) at deepest and surface points. Crack growth and the crack shape with loading cycles have been evaluated. In order to validate the analytical procedure/results, experiments have been carried out on full scale pipe and pipe welds with part through circumferential crack. Fatigue crack growth life evaluated using both schemes have been compared with experimental results. Use of stress intensity factor (K{sub RMS}) evaluated using second scheme gives better fatigue crack growth life prediction compared to that of first scheme. Fatigue crack growth in pipe weld (Gas Tungsten Arc Welding) can be predicted well using Paris constants of base material but prediction is non-conservative for pipe weld (Shielded Metal Arc Welding). Further, predictions using fatigue crack growth rate curve of ASME produces conservative results for pipe and GTAW pipe welds and comparable results for SMAW pipe welds. - Highlights: > Predicting fatigue crack growth of Austenitic Stainless Steel pipes and pipe welds. > Use of RMS-SIF and

  13. Heat Pipe Materials Compatibility

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.


    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  14. Introduction to Heat Pipes

    Ku, Jentung


    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  15. Heat Pipe Planets

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.


    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  16. Uncertainty analysis for probabilistic pipe fracture evaluations in LBB applications

    Rahman, S.; Ghadiali, N.; Wilkowski, G.


    During the NRC`s Short Cracks in Piping and Piping Welds Program at Battelle, a probabilistic methodology was developed to conduct fracture evaluations of circumferentially cracked pipes for application to leak-rate detection. Later, in the IPIRG-2 program, several parameters that may affect leak-before-break and other pipe flaw evaluations were identified. This paper presents new results from several uncertainty analyses to evaluate the effects of normal operating stresses, normal plus safe-shutdown earthquake stresses, off-centered cracks, restraint of pressure-induced bending, and dynamic and cyclic loading rates on the conditional failure probability of pipes. systems in BWR and PWR. For each parameter, the sensitivity to conditional probability of failure and hence, its importance on probabilistic leak-before-break evaluations were determined.

  17. Risk Factors associated with Paraurethral Duct Dilatation following Gonococcal Paraurethral Duct Infection in Men

    Fan, Wenge; Zhang, Qingsong; Wang, Lin; Ye, Xun; Jiang, Tingwang


    No studies have explored the risk factors for paraurethral duct dilatation following paraurethral duct infection by Neisseria gonorrhoeae in men undergoing ceftriaxone therapy. The present study was performed to explore the risk factors for paraurethral duct dilatation following paraurethral duct infection by N. gonorrhoeae in men undergoing ceftriaxone therapy and thus guide clinical interventions. We compared the demographic, behavioral, and clinical data of men with paraurethral duct infection by N. gonorrhoeae with and without dilatation of the paraurethral duct. Univariate analysis showed significant differences in age, disease course of the infected paraurethral duct, Chlamydia trachomatis infection in the paraurethral duct, and a history of paraurethral duct infection by N. gonorrhoeae between the patient and control groups (Pgonorrhoeae in men. Age, C. trachomatis infection in the paraurethral duct, and a history of paraurethral duct infection by N. gonorrhoeae are also risk factors. Thus, educating patients to undergo timely therapy and treating the C. trachomatis infection may be effective interventions. PMID:27861521

  18. Explosive welding of pipes

    Drennov, O.; Burtseva, O.; Kitin, A. [Russian Federal Nuclear Center, Sarov (Russian Federation)


    Arrangement of pipelines for the transportation of oil and gas is a complicated problem. In this paper it is suggested to use the explosive welding method to weld pipes together. This method is rather new. This method can be advantageous (saving material and physical resources) comparing to its static analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. We suggest to perform explosive welding according to the following scheme: the ends of the 2 pipes are connected, the external surfaces are kept at a similar level. A cylindrical steel layer of diameter larger than the pipe diameter is set around the pipe joint and an explosive charge is placed on its external surface. The basic problem is the elimination of strains and reduction of pipe diameter in the area of the dynamic effect. The suggestion is to use water as filler: the volume of pipes in the area adjacent to the zone of explosive welding is totally filled with water. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gas dynamic and elastic-plastic calculations we determined non-deformed mass of water. Model experiments with pipes having radii R = 57 mm confirmed results of the calculations and the possibility in principle to weld pipes by explosion with use of water as filler.

  19. Optimization of Pipe Networks

    Hansen, C. T.; Madsen, Kaj; Nielsen, Hans Bruun


    The paper treats a piping system, where the layout of the network is given but the diameters of the pipes should be chosen among a small number of different values. The cost of realizing the system should be minimized while keeping the energy heads at the nodes above some lower limits. A new...

  20. A heat pipe

    Rachev, L.A.; Kravtsov, A.A.


    A thermal pipe is described which contains a hermetically sealed body with a reticular filler. In order to increase the transmitted thermal power, the pipe is equipped with a high voltage source and with insulators, located between the wall of the body and the filler, where the latter is switched in to the high voltage source, preferably an adjustable one.

  1. An isolated nasolacrimal duct osteoma.

    Kim, Joo Yeon; Kwon, Jae Hwan


    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.

  2. The generation of sound by vorticity waves in swirling duct flows

    Howe, M. S.; Liu, J. T. C.


    Swirling flow in an axisymmetric duct can support vorticity waves propagating parallel to the axis of the duct. When the cross-sectional area of the duct changes a portion of the wave energy is scattered into secondary vorticity and sound waves. Thus the swirling flow in the jet pipe of an aeroengine provides a mechanism whereby disturbances produced by unsteady combustion or turbine blading can be propagated along the pipe and subsequently scattered into aerodynamic sound. In this paper a linearized model of this process is examined for low Mach number swirling flow in a duct of infinite extent. It is shown that the amplitude of the scattered acoustic pressure waves is proportional to the product of the characteristic swirl velocity and the perturbation velocity of the vorticity wave. The sound produced in this way may therefore be of more significance than that generated by vorticity fluctuations in the absence of swirl, for which the acoustic pressure is proportional to the square of the perturbation velocity. The results of the analysis are discussed in relation to the problem of excess jet noise.

  3. Assessment of Pipe Coupling by Using the Recovery of Stress-Induced Martensites in Superelastic Cu-11.8Al-0.6Be-0.5Nb Alloy

    de Oliveira, Danniel F.; Brito, Ieverton Caindre A.; França, Fabio José C.; de Lima, Severino Jackson G.; Mello, Tadeu Antonio A.; Gomes, Rodinei M.


    Superelastic Cu-11.8wt.%Al-0.6wt.%Be-0.5wt.%Nb shape memory alloy was tested under loading and unloading tensile tests at different temperatures and different strain rates of 5 × 10-4 s-1 and 1 × 10-5 s-1. The results of tests performed at 243 and 298 K demonstrate that this Cu-Al-Be alloy exhibits an appreciable amount of residual strain at room temperature, reaching strain levels as high as high as 4% when tested at 243 K for an imposed deformation of 7%. The residual stress associated with retained martensite is reverted by heating at the new austenite start ( A s) temperature, which is 60 °C higher than that of the initial alloy. In addition, with increasing temperature, the critical stress for the austenite → martensite transformation increases. Tube joining experiments show that the reversion of retained martensite is very effective to make pipe coupler fittings. The reversion of stress-induced martensite results in a coupling with a pull-out force equivalent to that obtainable by conventional shape memory effect.

  4. Study on Monitoring Rock Burst through Drill Pipe Torque

    Zhonghua Li


    Full Text Available This paper presents a new method to identify the danger of rock burst from the response of drill pipe torque during drilling process to overcome many defects of the conventional volume of drilled coal rubble method. It is based on the relationship of rock burst with coal stress and coal strength. Through theoretic analysis, the change mechanism of drill pipe torque and the relationship of drill pipe torque with coal stress, coal strength, and drilling speed are investigated. In light of the analysis, a new device for testing drill pipe torque is developed and a series of experiments is performed under different conditions; the results show that drill pipe torque linearly increases with the increase of coal stress and coal strength; the faster the drilling speed, the larger the drill pipe torque, and vice versa. When monitoring rock burst by drill pipe torque method, the index of rock burst is regarded as a function in which coal stress index and coal strength index are principal variables. The results are important for the forecast of rock burst in coal mine.

  5. Oscillating heat pipes

    Ma, Hongbin


    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  6. The monster sound pipe

    Ruiz, Michael J.; Perkins, James


    Producing a deep bass tone by striking a large 3 m (10 ft) flexible corrugated drainage pipe immediately grabs student attention. The fundamental pitch of the corrugated tube is found to be a semitone lower than a non-corrugated smooth pipe of the same length. A video ( of the demonstration is included, which illustrates how an Internet keyboard can be used to estimate the fundamental pitches of each pipe. Since both pipes have similar end corrections, the pitch discrepancy between the smooth pipe and drainage tube is due to the corrugations, which lower the speed of sound inside the flexible tube, dropping its pitch a semitone.

  7. Chronic Exposure to Water-Pipe Smoke Induces Alveolar Enlargement, DNA Damage and Impairment of Lung Function

    Abderrahim Nemmar


    Full Text Available Background/Aim: Epidemiological evidence indicates that water-pipe smoking (WPS adversely affects the respiratory system. However, the mechanisms underlying its effects are not well understood. Recent experimental studies reported the occurrence of lung inflammation and oxidative stress following acute and subacute exposure to WPS. Here, we wanted to verify the extent of inflammation and oxidative stress in mice chronically-exposed to WPS and to evaluate, for the first time, its effect on alveolar injury and DNA damage and their association with impairment of lung function. Methods: Mice were nose-only exposed to mainstream WPS (30 min/day; 5 days/week for 6 consecutive months. Control mice were exposed using the same protocol to atmospheric air only. At the end of the exposure period, several respiratory parameters were assessed. Results: In bronchoalveolar lavage fluid, WPS increased neutrophil and lymphocyte numbers, lactate dehydrogenase, myeloperoxidase and matrix metallopeptidase 9 activities, as well as several proinflammatory cytokines. In lung tissue, lipid peroxidation, reactive oxygen species, superoxide dismutase activity and reduced glutathione were all increased by WPS exposure. Along with oxidative stress, WPS exposure significantly increased lung DNA damage index. Histologically the lungs of WPS-exposed mice had foci of mixed inflammatory cells infiltration in the interalveolar interstitium which consisted of neutrophils, lymphocytes and macrophages. Interestingly, we found dilated alveolar spaces and alveolar ducts with damaged interalveolar septae, and impairment of lung function following WPS exposure. Conclusion: We show the persistence of lung inflammation and oxidative stress in mice chronically-exposed to WPS and demonstrate, for the first time, the occurrence of DNA damage and enlargement of alveolar spaces and ducts associated with impairment of lung function. Our findings provide novel mechanistic elucidation for the

  8. Numerical simulation on thermal stress of solar high-temperature shaped heat pipes%太阳能高温异型热管热应力数值摸拟

    曾金令; 马炎; 马婷婷; 朱跃钊; 杨谋存; 陈海军


    During high temperature thermo-chemical conversion utilization of solar,problems like local high temperature and poor heat transfer between two cavities occurred in the conventional directly and indirectly irradiated solar high temperature reactors.Thus,a new solar high-temperature phase transition reactor was developed by using high temperature heat plate-heat pipe technology.Its key part is high temperature shaped heat pipe (HTSHP).To investigate the heat bearing capacity of the HTSHP,the temperature field, stress field and thermal deformation of the HTSHP was numerically simulated,by establishing the thermal resistance model of the HTSHP and using thermal-stress coupling function of the large finite element anal-ysis software ANSYS.The analysis shows that,the maximum temperature of the HTSHP is 768 ℃,the maximum temperature difference is 1 8 ℃ and the temperature uniformity and heat transfer capability is ex-cellent.The thermal stress concentration occurs on the transitionally connecting heat plate.The maximum stress is 24.6 MPa,meeting the assessment requirements of the Steel Pressure Vessels- Analysis and De-sign Standard (JB/T4732—2005).%在太阳能高温热化学转化利用中,传统的直接照射式太阳能高温反应器和间接照射式两腔太阳能高温反应器均存在局部高温热点、两腔间传热能力差等问题.为此,应用高温热板-热管技术研制了新型太阳能高温相变反应器,其核心部件为高温异型热管(HTSHP).为分析HTSHP的热承载能力,构建了传热热阻模型,采用有限元分析软件 ANSYS 的热-应力耦合功能,对 HTSHP 在稳态条件下的温度场、应力场、热变形进行了数值模拟.结果表明, HTSHP最高温度为768℃,最大温差为18℃,均温性和传热能力较好;热应力集中于过渡连接的热板内壁上,最大应力为24.6 MPa,满足钢制压力容器分析设计标准的要求.

  9. Investigation of Counter-Flow in a Heat Pipe-Thermoelectric Generator (HPTEG)

    Remeli, Muhammad Fairuz; Singh, Baljit; Affandi, Nor Dalila Nor; Ding, Lai Chet; Date, Abhijit; Akbarzadeh, Aliakbar


    This study explores a method of generating electricity while recovering waste heat through the integration of heat pipes and thermoelectric generators (i.e. HPTEG system). The simultaneous waste heat recovery and power generation processes are achieved without the use of any moving parts. The HPTEG system consists of bismuth telluride thermoelectric generators (TEG), which are sandwiched between two finned pipes to achieve a temperature gradient across the TEG for electricity generation. A counter-flow heat exchanger was built using two separate air ducts. The air ducts were thermally coupled using the HPTEG modules. The evaporator section of the heat pipe absorbed the waste heat in a hot air duct. The heat was then transferred across the TEG surfaces. The condenser section of the HPTEG collected the excess heat from the TEG cold side before releasing it to the cold air duct. A 2-kW electrical heater was installed in the hot air duct to simulate the exhaust gas. An air blower was installed at the inlet of each duct to direct the flow of air into the ducts. A theoretical model was developed for predicting the performance of the HPTEG system using the effectiveness-number of transfer units method. The developed model was able to predict the thermal and electrical output of the HPTEG, along with the rate of heat transfer. The results showed that by increasing the cold air velocity, the effectiveness of the heat exchanger was able to be increased from approximately 52% to 58%. As a consequence of the improved heat transfer, maximum power output of 4.3 W was obtained.

  10. Fragmentation of common bile duct and pancreatic duct stones by extracorporeal shock-wave lithotripsy

    Kim, Ham Gyum [Ansan Junior College, Seoul (Korea, Republic of); Son, Soon Yong; Lee, Won Hong [Asan Medical Center, Seoul (Korea, Republic of)


    To determine its usefulness and safety of extracorporeal shock-wave lithotripsy in common bile duct and pancreatic duct stones, we analyzed the results of 13 patients with common bile duct stones and 6 patients with pancreatic duct stones which were removed by endoscopic procedures using the balloon or basket, who was performed the extracorporeal shock-wave lithotripsy using the ultrasonography for stone localization with a spark gap type Lithotriptor(Dornier MPL 9000, Germany). Fragmentation and complete clearance of the common bile duct and pancreatic duct stones were obtained in 19 of 19 patients(100%). Apart from transient attacks of fever in 2 of 13 patients with common bile duct stones(15%) and mild elevation of serum amylase and lipase in 2 of 6 patients with pancreatic duct stones(33%), no other serious side effects were observed. In our experiences, extracorporeal shock-wave lithotripsy is a safe and useful treatment for endoscopically unretrievable common bile duct and pancreatic duct stones.

  11. Vitellointestinal Duct Anomalies in Infancy

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


    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

  12. Fan/Ram Duct Program


    mwm^mmmt c INPUT I ] H—f TRANSIENT ROUTINE P"" CONTROL """I FAN ] COMPRESSOR MAIN BURNER I DUCT HZ HIGH TURBINE in— LOW TURBINE I...and pressure ratio. 6. Low Turbine Low turbine characteristics, identical In form to those of the high turbine, are shown in figures 27 and 28. 7

  13. Reeling of tight fit pipe

    Focke, E.S.


    If it would be possible to install Tight Fit Pipe by means of reeling, it would be an attractive new option for the exploitation of offshore oil and gas fields containing corrosive hydrocarbons. Tight Fit Pipe is a mechanically bonded double walled pipe where a corrosion resistant alloy liner pipe

  14. Experimenting with a "Pipe" Whistle

    Stafford, Olga


    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

  15. The Stress Intensity Factor Variation of Two Cracks Interaction in Nuclear Piping%两裂纹在核管道中应力强度因子的相互影响研究

    白鑫; 谢里阳


    With the aging of nuclear power plants,safety assessment for nuclear pipeline becomes more important.In the past,the assessment of nuclear piping only consider a single crack problem;or confined to the issue of a main crack;or focused on considering two cracks meeting any condition to be merged into one crack,namely,detailed study on multiple cracks under the stress intensity factor variation is rough.It is not a perfect part of fracture mechanics for multiple crack problems.In order to improve the content of fracture mechanics,fracture mechanics applied to increase the value and improve the safety and reliability of nuclear piping,inner surface cracks is determined as the major flaws of nuclear piping,the role of nuclear piping two cracks stress intensity factor and its general form are obtained by analysis of the actual variation with the finite element method.Two crack phenomenon is the basic situation of multiple cracks.Thus,this work provides a method to assess the basis for the existence of multiple cracks in nuclear safety pipeline.%随着核电站的老化,核管道安全评估变得更为重要。以往核管道的损伤容限评定通常只考虑单一裂纹问题,或只局限于研究一个主裂纹的问题,或主要集中于考虑两个裂纹满足何条件时,二者方可合并为一个裂纹的问题,对多裂纹情况下应力强度因子变化规律的研究较粗糙。在理论与方法方面,多裂纹问题一直是断裂力学不够完善的部分。本文以核管道的内表面裂纹为对象,采用有限元法分析核管道两个裂纹情况下的应力强度因子,得到其随裂纹间距、裂纹长度、裂纹深度变化的规律。又两个裂纹的现象为多裂纹现象中最基本的情况,即本研究工作可为存在多裂纹的核管道的安全评估提供方法依据。

  16. Flow induced pulsations in pipe systems

    Bruggeman, Jan Cornelis


    The aeroacoustic behavior of a low Mach number, high Reynolds number flow through a pipe with closed side branches was investigated. Sound is generated by coherent structures of concentrated vorticity formed periodically in the separated flow in the T-shaped junctions of side branches and the main pipe. The case of moderate pulsation amplitudes was investigated. It appears that the vortical flow in a T-joint is an aeroacoustic source of constant strength when acoustic energy losses due to radiation and friction are small but not negligible. When acoustic energy losses due to radiation and friction are negligible, the nonlinear character of vortex damping is the amplitude limiting mechanism. It is stressed that aeroacoustic sources should not be neglected in studies of the response of a piping lay-out with flow to, e.g., the pulsating output of a compressor.

  17. Pipe drafting and design

    Parisher, Roy A


    Pipe Drafting and Design, Third Edition provides step-by-step instructions to walk pipe designers, drafters, and students through the creation of piping arrangement and isometric drawings. It includes instructions for the proper drawing of symbols for fittings, flanges, valves, and mechanical equipment. More than 350 illustrations and photographs provide examples and visual instructions. A unique feature is the systematic arrangement of drawings that begins with the layout of the structural foundations of a facility and continues through to the development of a 3-D model. Advanced chapters

  18. Optimization of Pipe Networks

    Hansen, C. T.; Madsen, Kaj; Nielsen, Hans Bruun


    The paper treats a piping system, where the layout of the network is given but the diameters of the pipes should be chosen among a small number of different values. The cost of realizing the system should be minimized while keeping the energy heads at the nodes above some lower limits. A new...... algorithm using successive linear programming is presented. The performance of the algorithm is illustrated by optimizing a network with 201 pipes and 172 nodes. It is concluded that the new algorithm seems to be very efficient and stable, and that it always finds a solution with a cost near the best...

  19. An electrohydrodynamic heat pipe.

    Jones, T. B.


    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  20. Electrohydrodynamic heat pipes.

    Jones, T. B.


    An electrohydrodynamic heat pipe of radical design is proposed which substitutes polarization electrohydrodynamic force effects for capillarity in collecting, guiding, and pumping a condensate liquid phase. The discussed device is restricted to the use of dielectric liquids as working fluids. Because of the relatively poor thermal transport properties of these liquids, capillary heat pipes using these liquids have not been high performance devices. The employment of the electrohydrodynamic concept should enhance this performance and help fill the performance gap that exists in the temperature range from 250 F to 750 F for 'conventional' capillary heat pipes.

  1. Piping system subjected to seismic hard rock high frequencies

    Rydell, Cecilia, E-mail: [KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Vattenfall AB, SE-169 92 Stockholm (Sweden); Malm, Richard; Ansell, Anders [KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden)


    Highlights: • A study of the influence of support gaps in the analysis of a piping system. • Piping system located within a nuclear power plant reactor containment building. • Piping system subjected to a seismic hard rock high-frequency load. • Comparison of low- and high-frequency seismic loads. • The influence on the stress response of piping and acceleration response of valves. - Abstract: This paper addresses the influence of support gaps in the analyses of a piping system when subjected to a seismic hard rock high-frequency load. The system is located within the reactor containment building of a nuclear power plant and is assessed to be susceptible to high-frequency loads. The stress response of the pipe and the acceleration response of the valves are evaluated for different support gap sizes. It is shown that the inclusion of the support gaps in the analyses reduces the stress response for almost all pipe elements. On the other hand, the acceleration response of the valves is not necessarily reduced by the consideration of the gaps.

  2. Uniaxial Fatigue of HDPE-100 Pipe. Experimental Analysis

    A. Aid


    Full Text Available In this paper, an experimental analysis for determining the fatigue strength of PE-100, one of the most used High Density Polyethylene (HDPE materials for pipes, under cyclic axial loadings is presented. HDPE is a thermoplastic material used for piping systems, such as natural gas distribution systems, sewer systems and cold water systems, which provides a good alternative to metals such as cast iron or carbon steel. One of the causes for failures of HDPE pipes is fatigue which is the result of pipes being subjected to cyclic loading, such as internal pressure, weight loads or external loadings on buried pipes, which generate stress in different directions: circumferential, longitudinal and radial. HDPE pipes are fabricated using an extrusion process, which generates anisotropic properties. By testing in the Laboratory a series of identical specimens obtained directly from PE-100 HDPE pipes in longitudinal directions, the relationships between amplitude stress and number of cycles (S-N curve test frequency 2 Hz and stress ratio R = 0.0 are established.

  3. Monitoring of Grouting Compactness in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers.

    Jiang, Tianyong; Kong, Qingzhao; Wang, Wenxi; Huo, Linsheng; Song, Gangbing


    A post-tensioning tendon duct filled with grout can effectively prevent corrosion of the reinforcement, maintain bonding behavior between the reinforcement and concrete, and enhance the load bearing capacity of concrete structures. In practice, grouting of the post-tensioning tendon ducts always causes quality problems, which may reduce structural integrity and service life, and even cause accidents. However, monitoring of the grouting compactness is still a challenge due to the invisibility of the grout in the duct during the grouting process. This paper presents a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real time. A segment of a commercial tendon duct was used as research object in this study. One lead zirconate titanate (PZT) piezoceramic transducer with marble protection, called a smart aggregate (SA), was bonded on the tendon and installed in the tendon duct. Two PZT patch sensors were mounted on the top outside surface of the duct, and one PZT patch sensor was bonded on the bottom outside surface of the tendon duct. In the active sensing approach, the SA was used as an actuator to generate a stress wave and the PZT sensors were utilized to detect the wave response. Cement or grout in the duct functions as a wave conduit, which can propagate the stress wave. If the cement or grout is not fully filled in the tendon duct, the top PZT sensors cannot receive much stress wave energy. The experimental procedures simulated four stages during the grout pouring process, which includes empty status, half grouting, 90% grouting, and full grouting of the duct. Experimental results show that the bottom PZT sensor can detect the signal when the grout level increases towards 50%, when a conduit between the SA and PZT sensor is formed. The top PZT sensors cannot receive any signal until the grout process is completely finished. The wavelet packet-based energy analysis was adopted in this research to

  4. Monitoring of Grouting Compactness in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers

    Tianyong Jiang


    Full Text Available A post-tensioning tendon duct filled with grout can effectively prevent corrosion of the reinforcement, maintain bonding behavior between the reinforcement and concrete, and enhance the load bearing capacity of concrete structures. In practice, grouting of the post-tensioning tendon ducts always causes quality problems, which may reduce structural integrity and service life, and even cause accidents. However, monitoring of the grouting compactness is still a challenge due to the invisibility of the grout in the duct during the grouting process. This paper presents a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real time. A segment of a commercial tendon duct was used as research object in this study. One lead zirconate titanate (PZT piezoceramic transducer with marble protection, called a smart aggregate (SA, was bonded on the tendon and installed in the tendon duct. Two PZT patch sensors were mounted on the top outside surface of the duct, and one PZT patch sensor was bonded on the bottom outside surface of the tendon duct. In the active sensing approach, the SA was used as an actuator to generate a stress wave and the PZT sensors were utilized to detect the wave response. Cement or grout in the duct functions as a wave conduit, which can propagate the stress wave. If the cement or grout is not fully filled in the tendon duct, the top PZT sensors cannot receive much stress wave energy. The experimental procedures simulated four stages during the grout pouring process, which includes empty status, half grouting, 90% grouting, and full grouting of the duct. Experimental results show that the bottom PZT sensor can detect the signal when the grout level increases towards 50%, when a conduit between the SA and PZT sensor is formed. The top PZT sensors cannot receive any signal until the grout process is completely finished. The wavelet packet-based energy analysis was adopted in this

  5. The propagation law and analysis of gas explosion in U type duct

    YE Qing; LIN Bai-quan; JIA Zhen-zhen; FENG Tao; WANG Hai-qiao


    In order to explore the propagation law of gas explosion in U type laneways, the propagation law of flame and shock wave in U type duct were experimentally and theoretically investigated. It is shown that the shock wave takes on the complicated stress state and the flame takes on complicated change rules in the U type duct. The propagation process of gas explosion in bend duct is the mutual action of explosion wave, flame and complicate flow, the destruction in bend surface is especially serious. In the mine exploitation and laneway design, the bend laneway should be avoided, especially continuous bend laneway.

  6. Study on 3D finite element simulation of high frequency welded pipe welding residual stress%高频直缝焊管焊接残余应力的三维有限元模拟研究

    于恩林; 韩毅; 谷绪地; 张洪亮


    基于高频直缝焊管焊接热源的计算结果,综合考虑材料的物理属性随温度的高度非线性变化,以及高频加热的焊缝热影响区特有的温度分布规律,利用ANSYS有限元软件建立了高频直缝焊管焊接残余应力的三维有限元模型.获得了高频焊管温度场和残余应力场的分布规律,并对结果进行了分析.通过后处理模块,给出了焊缝部位残余应力的分布趋势,并分析了高频感应焊接残余应力的主要形成原因.发现焊缝附近的轴向残余应力较大,其中有些数值接近材料的屈服强度,而周向残余应力仅为材料屈服应力的1/3左右,径向残余应力数值较小,工程上可以忽略.%Based on the high-frequency longitudinal welding heat calculations, ANSYS finite element software is used to establish the three-dimensional finite element model of welding residual stress. Physical properties of materials with highly non-linear changes in temperature and high-frequency heating of the weld heat affected zone-specific temperature distribution are considered. High-frequency welded pipe temperature field and residual stress field distribution are obtained, and the results are analyzed. Trends of the main causes of the high frequency induction welding residual stress are analyzed through the post-processing module. The axial residual stress of near the weld seam are larger, and some of the values are close to the material yield strength. Residual stress in the circumferential direction is one-third of the material yield stress, and radial residual stress value is smaller that in projects can be ignored.

  7. An electrohydrodynamic heat pipe

    Jones, T. B.


    Dielectric liquid for transfer of heat provides liquid flow from the condenser section to the evaporator section in conventional heat pipes. Working fluid is guided or pumped by an array of wire electrodes connected to a high-voltage source.

  8. Finite-element analysis of flawed and unflawed pipe tests

    James, R.J.; Nickell, R.E.; Sullaway, M.F. (ANATECH Research Corp., La Jolla, CA (USA))


    Contemporary versions of the general purpose, nonlinear finite element program ABAQUS have been used in structural response verification exercises on flawed and unflawed austenitic stainless steel and ferritic steel piping. Among the topics examined, through comparison between ABAQUS calculations and test results, were: (1) the effect of using variations in the stress-strain relationship from the test article material on the calculated response; (2) the convergence properties of various finite element representations of the pipe geometry, using shell, beam and continuum models; (3) the effect of test system compliance; and (4) the validity of ABAQUS J-integral routines for flawed pipe evaluations. The study was culminated by the development and demonstration of a macroelement'' representation for the flawed pipe section. The macroelement can be inserted into an existing piping system model, in order to accurately treat the crack-opening and crack-closing static and dynamic response. 11 refs., 20 figs., 1 tab.

  9. Silicon Heat Pipe Array

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.


    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  10. Stuck pipe prediction

    Alzahrani, Majed


    Disclosed are various embodiments for a prediction application to predict a stuck pipe. A linear regression model is generated from hook load readings at corresponding bit depths. A current hook load reading at a current bit depth is compared with a normal hook load reading from the linear regression model. A current hook load greater than a normal hook load for a given bit depth indicates the likelihood of a stuck pipe.

  11. The Monster Sound Pipe

    Ruiz, Michael J.; Perkins, James


    Producing a deep bass tone by striking a large 3 m (10 ft) flexible corrugated drainage pipe immediately grabs student attention. The fundamental pitch of the corrugated tube is found to be a semitone lower than a non-corrugated smooth pipe of the same length. A video ( of the demonstration is included, which…

  12. Predicting Turbulent Convective Heat Transfer in Fully Developed Duct Flows

    Rokni, Masoud; Gatski, Thomas B.


    The performance of an explicit algebraic stress model (EASM) is assessed in predicting the turbulent flow and forced heat transfer in both straight and wavy ducts, with rectangular, trapezoidal and triangular cross-sections, under fully developed conditions. A comparison of secondary flow patterns. including velocity vectors and velocity and temperature contours, are shown in order to study the effect of waviness on flow dynamics, and comparisons between the hydraulic parameters. Fanning friction factor and Nusselt number, are also presented. In all cases. isothermal conditions are imposed on the duct walls, and the turbulent heat fluxes are modeled using gradient-diffusion type models. The formulation is valid for Reynolds numbers up to 10(exp 5) and this minimizes the need for wall functions that have been used with mixed success in previous studies of complex duct flows. In addition, the present formulation imposes minimal demand on the number of grid points without any convergence or stability problems. Criteria in terms of heat transfer and friction factor needed to choose the optimal wavy duct cross-section for industrial applications among the ones considered are discussed.

  13. Heat pipe dynamic behavior

    Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.


    The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

  14. Fracture mechanics models developed for piping reliability assessment in light water reactors: piping reliability project

    Harris, D.O.; Lim, E.Y.; Dedhia, D.D.; Woo, H.H.; Chou, C.K.


    The efforts concentrated on modifications of the stratified Monte Carlo code called PRAISE (Piping Reliability Analysis Including Seismic Events) to make it more widely applicable to probabilistic fracture mechanics analysis of nuclear reactor piping. Pipe failures are considered to occur as the result of crack-like defects introduced during fabrication, that escape detection during inspections. The code modifications allow the following factors in addition to those considered in earlier work to be treated: other materials, failure criteria and subcritical crack growth characteristic; welding residual and vibratory stresses; and longitudinal welds (the original version considered only circumferential welds). The fracture mechanics background for the code modifications is included, and details of the modifications themselves provided. Additionally, an updated version of the PRAISE user's manual is included. The revised code, known as PRAISE-B was then applied to a variety of piping problems, including various size lines subject to stress corrosion cracking and vibratory stresses. Analyses including residual stresses and longitudinal welds were also performed.

  15. 基于RCC-M与ASME的核2/3级管道应力评定比较%Comparision between RCC-M and ASME for Stress Evaluation of Nuclear Safety Class 2/3 Pipes

    刘锐; 李铁萍; 张春明


    RCC-M Design and Construction Rules for Mechanical Components of PWR Nuclear Islands and ASME American Society of Mechanical Engineers are widely used in China. They are similar specifications with differences. It discusses the stress analysis and evaluation methods for nuclear safety class 2/3 pipes, summarizes the requirements of RCC - M and ASME about stress evaluation and compares the differences. Such as the application of PIPESTRESS for the evaluation of stress, respectively according to RCC - M and ASME, shows that the total stress calculation results is closely related to stress increase coefficient and stress index. RCC - M standard focuses on the influence of pressure, and ASME standard focuses on the influence of gravity and accidental loading. When the internal pressure is lesser, ASME is relatively safer. When the internal pressure is bigger,and the gravity and accidental loading is lesser,RCC - M is relatively safer.%RCC-M《法国压水堆机械设备制造与设计规范》和ASME《美国机械工程师协会标准》为目前核电厂广泛采用的技术标准,两者对压水堆核2/3级管道应力评定的规定相似但不完全相同.论述了核2/3级管道应力分析及评定的方法;总结了RCC-M规范和ASME标准对核2/3级管道应力评定的要求,比较了不同载荷工况下两者的差异;以某管道为例,应用PIPESTRESS软件分别按照RCC-M规范和ASME标准对其进行应力评定.结果表明:总应力计算结果与应力增强系数和一次应力指数关系密切,RCC-M规范侧重压力的影响,ASME标准侧重自重及偶然荷载的影响.在内压为零及内压不大的情况下,ASME相对RCC-M更偏于安全.而对于内压较大,自重及偶然荷载的影响较小的情况下,RCC-M相对ASME更偏于安全.

  16. Mechanism for in-pipe inspection; Dispositivo para inspecao de dutos

    Freitas, Gustavo Medeiros; Dutra, Max Suell [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)


    The internal inspection of pipes is becoming a routine activity thanks to their importance on transportation of substances such as oil and natural gas. This paper addresses a mechanism capable of working inside pipes of different diameters that may present extreme curves and inclinations. The mechanism is composed of modules with devices that provide adjustable contact with the duct, using wheels on the contact points. The robot moves inside the pipe creating a virtual spindle. For that, two parts are used: the first one, guided along the pipe by a set of wheels, moves parallel to the axis of the pipe; the second part is attached to a motor. The motor rotation forces the mechanism to follow a helical motion, with tilted wheels rotating about the axis of the pipe. Each adjustable contact device works like a lever, pressing the wheel against the pipe. The base of the device can be actively rotated, modifying the angle of the wheel in relation to the pipe (equivalent to the step of the spindle), permitting the motion of the system in both directions, with specific velocity. According to the applied angle, the robot changes the relation between torque and displacement velocity. (author)

  17. Heat Pipe Integrated Microsystems

    Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.


    The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached

  18. Turbulent pipe flows subjected to temporal decelerations

    Jeong, Wongwan; Lee, Jae Hwa


    Direct numerical simulations of temporally decelerating turbulent pipe flows were performed to examine effects of temporal decelerations on turbulence. The simulations were started with a fully developed turbulent pipe flow at a Reynolds number, ReD =24380, based on the pipe radius (R) and the laminar centerline velocity (Uc 0). Three different temporal decelerations were imposed to the initial flow with f= | d Ub / dt | =0.00127, 0.00625 and 0.025, where Ub is the bulk mean velocity. Comparison of Reynolds stresses and turbulent production terms with those for steady flow at a similar Reynolds number showed that turbulence is highly intensified with increasing f due to delay effects. Furthermore, inspection of the Reynolds shear stress profiles showed that strong second- and fourth-quadrant Reynolds shear stresses are greatly increased, while first- and third-quadrant components are also increased. Decomposition of streamwise Reynolds normal stress with streamwise cutoff wavelength (λx) 1 R revealed that the turbulence delay is dominantly originated from delay of strong large-scale turbulent structures in the outer layer, although small-scale motions throughout the wall layer adjusted more rapidly to the temporal decelerations. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2014R1A1A2057031).

  19. A Corrosion Risk Assessment Model for Underground Piping

    Datta, Koushik; Fraser, Douglas R.


    The Pressure Systems Manager at NASA Ames Research Center (ARC) has embarked on a project to collect data and develop risk assessment models to support risk-informed decision making regarding future inspections of underground pipes at ARC. This paper shows progress in one area of this project - a corrosion risk assessment model for the underground high-pressure air distribution piping system at ARC. It consists of a Corrosion Model of pipe-segments, a Pipe Wrap Protection Model; and a Pipe Stress Model for a pipe segment. A Monte Carlo simulation of the combined models provides a distribution of the failure probabilities. Sensitivity study results show that the model uncertainty, or lack of knowledge, is the dominant contributor to the calculated unreliability of the underground piping system. As a result, the Pressure Systems Manager may consider investing resources specifically focused on reducing these uncertainties. Future work includes completing the data collection effort for the existing ground based pressure systems and applying the risk models to risk-based inspection strategies of the underground pipes at ARC.

  20. Current surgical treatment for bile duct cancer

    Yasuji Seyama; Masatoshi Makuuchi


    Since extrahepatic bile duct cancer is difficult to diagnose and to cure, a safe and radical surgical strategy is needed. In this review, the modes of infiltration and spread of extrahepatic bile duct cancer and surgical strategy are discussed. Extended hemihepatectomy, with or without pancreatoduodenectomy (PD), plus extrahepatic bile duct resection and regional lymphadenectomy has recently been recognized as the standard curative treatment for hilar bile duct cancer. On the other hand, PD is the choice of treatment for middle and distal bile duct cancer. Major hepatectomy concomitant with PD (hepatopancreatoduodenectomy) has been applied to selected patients with widespread tumors. Preoperative biliary drainage (BD) followed by portal vein embolization (PVE) enables major hepatectomy in patients with hilar bile duct cancer without mortality. BD should be performed considering the surgical procedure, especially, in patients with separated intrahepatic bile ducts caused by hilar bile duct cancer. Right or left trisectoriectomy are indicated according to the tumor spread and biliary anatomy. As a result, extended radical resection offers a chance for cure of hilar bile duct cancer with improved resectability, curability, and a 5-year survival rate of 40%. A 5-year survival rate has ranged from 24% to 39% after PD for middle and distal bile duct cancer.



    A numerical study on the characteristics of developing turbulent flow in a curved pipe with a baffle was carried out in body-fitted coordinates with the k-ε model turbulence. A curved duct of square cross-section was examined first, and the results agree very well with the experimental data. Then two kinds of pipes, a normal curved pipe and that with a baffle were studied. The computational results are presented and compared with each other to illustrate the changes of the flow after adding the baffle. The longitudinal velocity in the pipe with a baffle was characterized by outer velocity bigger than the inner one. The secondary flow was characterized by four-vortex structure with the intensity reduced, which results in the equability of the flow field of the cross-section compared with that without a baffle, and has much more significant meaning in engineering.

  2. Seismic response analysis of a piping system subjected to multiple support excitations in a base isolated NPP building

    Surh, Han-Bum [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ryu, Tae-Young; Park, Jin-Sung [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Ahn, Eun-Woo; Choi, Chul-Sun [Korea Electric Power Corporation Engineering & Construction Company, Inc., 2354 Yonggu-daero, Giheung-gu, Yongin 446-713 (Korea, Republic of); Koo, Ja Choon [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Choi, Jae-Boong [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Kim, Moon Ki, E-mail: [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of)


    Highlights: • Piping system in the APR 1400 NPP with a base isolation design is studied. • Seismic response of piping system in base isolated building are investigated. • Stress classification method is examined for piping subjected to seismic loading. • Primary stress of piping is reduced due to base isolation design. • Substantial secondary stress is observed in the main steam piping. - Abstract: In this study, the stress response of the piping system in the advanced power reactor 1400 (APR 1400) with a base isolation design subjected to seismic loading is addressed. The piping system located between the auxiliary building with base isolation and the turbine building with a fixed base is considered since it can be subjected to substantial relative support movement during seismic events. First, the support responses with respect to the base characteristic are investigated to perform seismic analysis for multiple support excitations. Finite element analyses are performed to predict the piping stress response through various analysis methods such as the response spectrum, seismic support movement and time history method. To separately evaluate the inertial effect and support movement effect on the piping stress, the stress is decomposed into a primary and secondary stress using the proposed method. Finally, influences of the base isolation design on the piping system in the APR 1400 are addressed. The primary stress based on the inertial loading is effectively reduced in a base isolation design, whereas a considerable amount of secondary stress is generated in the piping system connecting a base isolated building with a fixed base building. It is also confirmed that both the response spectrum analysis and seismic support movement analysis provide more conservative estimations of the piping stress compared to the time history analysis.

  3. [Common bile duct stones and their complications].

    Millat, B; Borie, F


    At the time of cholecystectomy for symptomatic cholelithiasis, 7-20% of patients have common bile duct stones. Nearly one third of them are asymptomatic. Routine cholangiography during cholecystectomy allows the diagnosis and treatment of common bile duct stones during the same operation. Selective indication for the diagnosis of common bile duct stones based on the positive predictive value of indicators limits treatment to symptomatic cases. No single indicator is however completely accurate in predicting common bile duct stones and the natural history of asymptomatic cases is uncertain. Endoscopic stone extraction preceding cholecystectomy is not superior to one-stage surgical treatment. Diagnosis and treatment of common bile duct stones are feasible laparoscopically. Complications of common bile duct stones are cholangitis and acute pancreatitis; if severe, they require specific therapeutic approaches.

  4. Overview of piping issues and trends

    Bush, S.H.


    A variety of failure mechanisms that have contributed to failures in nuclear reactor piping systems are discussed: these include general corrosion, intergranular stress corrosion, erosion-corrosion, mechanical fatigue, and thermal fatigue covering the spectrum from mixing-tee to stratification. Actions to minimize or eliminate these failure mechanisms are discussed where these actions are based on the experience amassed over the past three decades.

  5. Heat pipes and use of heat pipes in furnace exhaust

    Polcyn, Adam D.


    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  6. Progress of interfacial shear stress in the gas-liquid stratified flow in horizontal pipes%水平管气液两相分层流界面剪切预测研究进展

    郑平; 赵梁


    The gas-liquid two-phase stratified flow has complex momentum and energy transmission phenomena at interface,although its pattern is simple. There are still no unified conclusions for interfacial shear stress in stratified flow. Current progress of interfacial shear stress in horizontal pipes were elaborated by theoretical models,experimental models and numerical simulations. As for theoretical models,closure models were established by models simplification and empirical correlations. Empirical correlations were corrected with closure relations in experiments. Due to simplifying assumptions and experimental conditions,there are some limitations in predicting the interfacial shear stress with theoretical and experimental ways. The detailed flow fields were studied by numerical simulations,but closure relations have been less obtained so far. Five existing models are compared according to liquid holdup and pressure drop. The future research trends of gas-liquid two-phase stratified flow interfacial shear stress in horizontal pipes were further discussed. More detailed local models are needed to be proposed and engineering practice should be taken into account. It is necessary to develop new methods of gas-liquid interface calculations and closure relations for numerical simulations.%水平管气液两相分层流虽流型简单,但由于界面存在复杂的动量和能量传递,分层流的界面剪切预测至今没有一致的结论。本文从理论模型、实验模型、数值计算3个角度出发,详细阐述水平管气液两相分层流界面剪切预测的研究现状,得出不同研究方法的优势和缺陷。针对3种研究方法,指出理论模型通过模型简化和经验关联式来建立封闭模型,实验模型则在封闭关系上修正经验关联式,但由于简化假设和实验条件的限制,使得这两种研究方法对界面剪切应力的预测具有一定的局限性;数值计算能够弥补机理模型在流场细

  7. Stress-analysis calculation for high-pressure GRP power-plant piping using the Finite Element Method; Statische Berechnungen von GFK-Druckleitungen von Kraftwerken mittels Finite-Elemente-Methode

    Mueller, R. [LGA Bautechnik GmbH, Nuernberg (Germany)


    This article deals with the structural analysis of embedded pipes with the help of numerical calculations by the finite element method (FEM). It focuses on the calculation of high pressure pipes made by glasfiber reinforced plastics (GRP), as there is an increasing use also for power plants in Germany. This article goes into details concerning the often used load cases and shows the characteristics using FEM for the dimensioning of embedded pipes. Furthermore a special application of FEM is presented which was used for finding a rehabilitation concept for a main cooling pipe. The quasi-static analysis of pipes, on which dynamic loads like earth quake or cyclic loads are applied, is shown. The experiences of the Institute of Structural Analysis of the LGA Bautechnik GmbH Nuremberg presented in this paper were collected on several construction sites of power plants all over the world. (orig.)

  8. Composite drill pipe

    Leslie, James C [Fountain Valley, CA; Leslie, II, James C.; Heard, James [Huntington Beach, CA; Truong, Liem , Josephson; Marvin, Neubert [Huntington Beach, CA; Hans, [Anaheim, CA


    A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

  9. Heat-pipe Earth.

    Moore, William B; Webb, A Alexander G


    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

  10. Pipe Drafting with CAD. Teacher Edition.

    Smithson, Buddy

    This teacher's guide contains nine units of instruction for a course on computer-assisted pipe drafting. The course covers the following topics: introduction to pipe drafting with CAD (computer-assisted design); flow diagrams; pipe and pipe components; valves; piping plans and elevations; isometrics; equipment fabrication drawings; piping design…

  11. Parametric simulation and experimental analysis of earth air heat exchanger with solar air heating duct

    Sanjeev Jakhar


    Full Text Available Earth air heat exchanger (EAHE systems are insufficient to meet the thermal comfort requirements in winter conditions. The low heating potential of such systems can be improved by integrating the system with solar air heating duct (SAHD. The aim of this paper is to present a model to estimate the heating potential for EAHE system with and without SAHD. The model is generated using TRNSYS 17 simulation tool and validated against experimental investigation on an experimental set-up in Ajmer, India. The experiment was done during the winter season, where the system was evaluated for different inlet flow velocities, length and depth of buried pipe. From the experimentation, it was observed that the depth of 3.7 m is sufficient for pipe burial and the 34 m length of pipe is sufficient to get optimum EAHE outlet temperature. It is also observed that increase in flow velocity results in drop in EAHE outlet temperature, while room temperature is found to increase for higher velocities (5 m/s. The COP of the system also increased up to 6.304 when assisted with solar air heating duct. The results obtained from the experiment data are in good agreement with simulated results within the variation of up to 7.9%.

  12. Methods of evaluating cleanliness of ventilation ducts

    曹勇; 罗运有; 于丹; 甘丽斯


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

  13. PE 100 pipe systems

    Brömstrup, Heiner


    English translation of the 3rd edition ""Rohrsysteme aus PE 100"". Because of the considerably increased performance, pipe and pipe systems made from 100 enlarge the range of applications in the sectors of gas and water supply, sewage disposal, industrial pipeline construction and in the reconstruction and redevelopment of defective pipelines (relining). This book applies in particular to engineers, technicians and foremen working in the fields of supply, disposal and industry. Subject matters of the book are all practice-relevant questions regarding the construction, operation and maintenance

  14. Numerical investigation on the axial interaction between buried district heating pipes and soil

    Weidlich, Ingo; Achmus, Martin


    Pipe-soil interaction has to be taken into account in the design of district heating (DH) pipes. The investigation presented here focuses on the effect of the reduction of axial friction forces due to cyclic axial displacements and the corresponding stress redistribution. Calculations with a three-dimensional finite element model were carried out in which a standard situation of a buried DH pipe was studied. A significant reduction of friction with cyclic axial displacements was obtained, although no temperature loading and thus no radial expansion of the pipe was considered. The reason for the friction force decrease is a densification of the soil beneath the pipe, which leads to a decrease of the normal stress acting between pipe and soil.

  15. Propagation of Sound at Moderate and High Intensities in Absorbent and Hard-Walled Cylindrical Ducts. Ph.D. Thesis

    Mcdaniel, Oliver Herbert


    The propagation of plane wave and higher order acoustic modes in both hard-walled and absorbent cylindrical ducts was studied at moderate sound intensities where the linear wave equation is valid, and at high intensities where nonlinear effects can be observed. The experiments were conducted with an anechoically terminated twelve-inch inside-diameter transite pipe. Various types of sound sources were mounted at one end of the duct to generate the desired acoustic fields within the duct. Arrays of conventional loudspeakers were used to generate plane waves and higher order acoustic modes at moderate intensities, and an array of four high intensity electro-pneumatic sound sources was used for the experiments in the nonlinear region. The attenuation of absorbent liners made of several different materials was obtained at moderate intensities for both plane waves and high order modes. It was found that the characteristics of the liners studied did not change appreciably at high intensities.

  16. Effects of bending-torsional duct-induced swirl distortion on aerodynamic performance of a centrifugal compressor

    Hou, Hongjuan; Wang, Leilei; Wang, Rui; Yang, Yanzhao


    A turbocharger compressor working in commercial vehicles, especially in some passenger cars, often works together with some pipes with complicated geometry as an air intake system, due to limit of available space in internal combustion engine compartments. These pipes may generate various distortions of physical parameters of the air at the inlet of the compressor and therefore the compressor aerodynamic performance deteriorates. Sometimes, the turbocharging engine fails to work at some operation points. This paper investigates the effects of various swirl distortions induced by different bending-torsional intake ducts on the aerodynamic performance of a turbocharger compressor by both 3D numerical simulations and experimental measurements. It was found that at the outlet of the pipes the different inlet ducts can generate different swirl distortions, twin vortices and bulk-like vortices with different rotating directions. Among them, the bulk-like vortices not only affect seriously the pressure distribution in the impeller domain, but also significantly deteriorate the compressor performance, especially at high flow rate region. And the rotating direction of the bulk-like vortices is also closely associated with the efficiency penalty. Besides the efficiency, the transient flow rate through a single impeller channel, or the asymmetric mass flow crossing the whole impeller, can be influenced by two disturbances. One is from the upstream bending-torsional ducts; other one is from the downstream volute.

  17. Explosive Welding of Pipes

    Drennov, Oleg; Drennov, Andrey; Burtseva, Olga


    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. Explosive welding of cylindrical surfaces is performed by launching of welded layer along longitudinal axis of construction. During this procedure, it is required to provide reliable resistance against radial convergent strains. The traditional method is application of fillers of pipe cavity, which are dense cylindrical objects having special designs. However, when connecting pipes consecutively in pipelines by explosive welding, removal of the fillers becomes difficult and sometimes impossible. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe.

  18. Aeronautical tubes and pipes

    Beauclair, N.


    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  19. Heat-pipe planets

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.


    Observations of the surfaces of all terrestrial bodies other than Earth reveal remarkable but unexplained similarities: endogenic resurfacing is dominated by plains-forming volcanism with few identifiable centers, magma compositions are highly magnesian (mafic to ultra-mafic), tectonic structures are dominantly contractional, and ancient topographic and gravity anomalies are preserved to the present. Here we show that cooling via volcanic heat pipes may explain these observations and provide a universal model of the way terrestrial bodies transition from a magma-ocean state into subsequent single-plate, stagnant-lid convection or plate tectonic phases. In the heat-pipe cooling mode, magma moves from a high melt-fraction asthenosphere through the lithosphere to erupt and cool at the surface via narrow channels. Despite high surface heat flow, the rapid volcanic resurfacing produces a thick, cold, and strong lithosphere which undergoes contractional strain forced by downward advection of the surface toward smaller radii. We hypothesize that heat-pipe cooling is the last significant endogenic resurfacing process experienced by most terrestrial bodies in the solar system, because subsequent stagnant-lid convection produces only weak tectonic deformation. Terrestrial exoplanets appreciably larger than Earth may remain in heat-pipe mode for much of the lifespan of a Sun-like star.

  20. [Piping cinnamon] 791

    W L H Skeen and Co


    279 x 211 mm. Showing female workers making cinnamon pipes. The cinnamon is placed on a low tripod formed from four sticks, and steadied with the operator's foot while the cuticle is scraped off with a small curved knife. Annotated '791' on the bottom right hand corner of the photograph. Date approximate.

  1. The attenuation of the higher-order cross-section modes in a duct with a thin porous layer.

    Yin, Yean; Horoshenkov, Kirill V


    A numerical method for sound propagation of higher-order cross-sectional modes in a duct of arbitrary cross-section and boundary conditions with nonzero, complex acoustic admittance has been considered. This method assumes that the cross-section of the duct is uniform and that the duct is of a considerable length so that the longitudinal modes can be neglected. The problem is reduced to a two-dimensional (2D) finite element (FE) solution, from which a set of cross-sectional eigen-values and eigen-functions are determined. This result is used to obtain the modal frequencies, velocities and the attenuation coefficients. The 2D FE solution is then extended to three-dimensional via the normal mode decomposition technique. The numerical solution is validated against experimental data for sound propagation in a pipe with inner walls partially covered by coarse sand or granulated rubber. The values of the eigen-frequencies calculated from the proposed numerical model are validated against those predicted by the standard analytical solution for both a circular and rectangular pipe with rigid walls. It is shown that the considered numerical method is useful for predicting the sound pressure distribution, attenuation, and eigen-frequencies in a duct with acoustically nonrigid boundary conditions. The purpose of this work is to pave the way for the development of an efficient inverse problem solution for the remote characterization of the acoustic boundary conditions in natural and artificial waveguides.

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

    Aldrich, R.; Puttagunta, S.


    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.

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

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


    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.

  4. Resistance Characteristics of Hydraulic Oil through Isodiametric T-type Duct with Sharp Corners

    TANG Jinglin; WANG Liwei; LI Xia


    Rational determination and reduction of local energy loss of oil flow at pipe junctions are of important significance to improve hydraulic pipeline's work efficiency, especially for complex hydraulic pipeline connected by isodiametric T-type ducts with sharp comers to get combined and divided flow. From this point of view, the formulae of resistance loss for combined flow and divided flow through isodiametric T-type duct with sharp comers as well as the correlations of resistance loss coefficients in the branches of the duct are derived using energy method. On this basis, resistance characteristics of hydraulic oil in the duct are obtained by numerical simulation of different flow modes, which are commonly applied in hydraulic pipelines, using computational fluid dynamics (CFD) method, and the reasons for the resistance loss are analyzed based on the pressure change mechanism in the flow field. A part of simulation results was validated with the reference data. The research shows that for combined flows the resistance loss of symmetrical is lower than that of tmsymmetrical to obtain low speed in common branch, but to gain high speed is quite the contrary, for divided flows, the symmetrical is always a reasonable choice to reduce resistance loss. These conclusions can be applied to optimize the design of hydraulic pipeline.

  5. Experimental investigation of high cycle thermal fatigue in a T-junction piping system

    Selvam, P. Karthick; Kulenovic, Rudi; Laurien, Eckart [Stuttgart Univ. (Germany). Inst. of Nuclear Technology and Energy Systems (IKE)


    High cycle thermal fatigue damage of structure in the vicinity of T-junction piping systems in nuclear power plants is of importance. Mixing of coolant streams at significant temperature differences causes thermal fluctuations near piping wall leading to gradual thermal degradation. Flow mixing in a T-junction is performed. The determined factors result in bending stresses being imposed on the piping system ('Banana effect').

  6. Radiated noise of ducted fans

    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.

  7. Piping structural design for the ITER thermal shield manifold

    Noh, Chang Hyun, E-mail: [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Chung, Wooho, E-mail: [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Nam, Kwanwoo; Kang, Kyoung-O. [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Bae, Jing Do; Cha, Jong Kook [Korea Marine Equipment Research Institute, Busan 606-806 (Korea, Republic of); Kim, Kyoung-Kyu [Mecha T& S, Jinju-si 660-843 (Korea, Republic of); Hamlyn-Harris, Craig; Hicks, Robby; Her, Namil; Jun, Chang-Hoon [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)


    Highlights: • We finalized piping design of ITER thermal shield manifold for procurement. • Support span is determined by stress and deflection limitation. • SQP, which is design optimization method, is used for the pipe design. • Benchmark analysis is performed to verify the analysis software. • Pipe design is verified by structural analyses. - Abstract: The thermal shield (TS) provides the thermal barrier in the ITER tokamak to minimize heat load transferred by thermal radiation from the hot components to the superconducting magnets operating at 4.2 K. The TS is actively cooled by 80 K pressurized helium gas which flows from the cold valve box to the cooling tubes on the TS panels via manifold piping. This paper describes the manifold piping design and analysis for the ITER thermal shield. First, maximum allowable span for the manifold support is calculated based on the simple beam theory. In order to accommodate the thermal contraction in the manifold feeder, a contraction loop is designed and applied. Sequential Quadratic Programming (SQP) method is used to determine the optimized dimensions of the contraction loop to ensure adequate flexibility of manifold pipe. Global structural behavior of the manifold is investigated when the thermal movement of the redundant (un-cooled) pipe is large.

  8. Double-duct liquid metal magnetohydrodynamic engine

    Haaland, Carsten M.


    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.

  9. A rare case of bile duct cyst

    Qing-Gang Wang; Shu-Tian Zhang


    Choledochal cyst is an uncommon disease usually seen in young women and can be divided into five types. We report a 66-year-old woman who was diagnosed with types Ⅱ and Ⅱ bile duct cyst simultaneously after surgery, which is a rare type of bile duct cyst.

  10. New cannulation method for pancreatic duct cannulation-bile duct guidewire-indwelling method

    Sakai, Yuji; Ishihara, Takeshi; Tsuyuguchi, Toshio; Tawada, Katsunobu; Saito, Masayoshi; Kurosawa, Jo; Tamura, Ryo; Togo, Seiko; Mikata, Rintaro; Tada, Motohisa; Yokosuka, Osamu


    The patient was a 58-year-old male with symptomatic alcoholic chronic pancreatitis. Since a 10 mm calculus was observed in the pancreatic body and abdominal pain occurred due to congestion of pancreatic juice, endoscopic retrograde cholangiopancreatography was conducted for assessment of the pancreatic duct and treatment of pancreatic calculus. Pancreatogram was slightly and insufficiently obtained by injecting the contrast media via the common channel of the duodenal main papilla. We tried to cannulate selectively into the pancreatic duct for a clear image. However, the selective cannulation of the pancreatic duct was difficult because of instability of the papilla. On the other hand, selective cannulation of the bile duct was relatively easily achieved. Therefore, after the imaging of the bile duct, a guidewire was retained in the bile duct to immobilize the duodenal papilla and cannulation of the pancreatic duct was attempted. As a result, selective pancreatic duct cannulation became possible. It is considered that the bile duct guidewire-indwelling method may serve as one of the useful techniques for cases whose selective pancreatic duct cannulation is difficult (“selective pancreatic duct difficult cannulation case”). PMID:22110840

  11. Pancreatic duct holder for facilitating duct-to-mucosa pancreatojejunostomy after pancreatoduodenectomy.

    Sugiyama, Masanori; Suzuki, Yutaka; Abe, Nobutsugu; Ueki, Hisayo; Masaki, Tadahiko; Mori, Toshiyuki; Atomi, Yutaka


    Duct-to-mucosa pancreatojejunostomy after pancreatoduodenectomy may be technically difficult, particularly in cases in which the remnant pancreas is soft with a small main pancreatic duct. We devised a pancreatic duct holder for duct-to-mucosa pancreatojejunostomy. The holder has a cone-shaped tip. A one-third circle of the tip is cut away, which makes a slit. As the tip is inserted gently into the pancreatic duct, the duct can be adequately expanded. The holder provides a good surgical field for anastomosis. A slit of the tip allows needle insertion. The holder facilitates stitches of the jejunum also. Twelve patients underwent pancreatoduodenectomy, followed by duct-to-mucosa pancreatojejunostomy using the holder. The holder allowed 8 or more stitches in duct-to-mucosa anastomosis, even in patients with a small pancreatic duct. No patients developed prolonged pancreatic leakage or pancreatic fistula postoperatively. In conclusion, the pancreatic duct holder is a simple and useful tool for facilitating duct-to-mucosa pancreatojejunostomy.

  12. Bile duct hamartomas (von Mayenburg complexes) mimicking liver metastases from bile duct cancer: MRC findings

    Yasuhiko Nagano; Kenichi Matsuo; Katsuya Gorai; Kazuya Sugimori; Chikara Kunisaki; Hideyuki Ike; Katsuaki Tanaka; Toshio Imada; Hiroshi Shimada


    We present a case of a 72-year-old man with a common bile duct cancer, who was initially believed to have multiple liver metastases based on computed tomography findings, and in whom magnetic resonance cholangiography (MRC) revealed a diagnosis of bile duct hamartomas. At exploration for pancreaticoduodenectomy, liver palpation revealed disseminated nodules at the surface of the liver. These nodules showed gray-white nodular lesions of about 0.5cm in diameter scattered on the surface of both liver lobes, which were looked like multiple liver metastases from bile duct cancer. Frozen section of the liver biopsy disclosed multiple bile ducts with slightly dilated lumens embedded in the collagenous stroma characteristics of multiple bile duct hamartomas (BDHs). Only two reports have described the MRC features of bile duct hamartomas. Of all imaging procedures, MRC provides the most relevant features for the imaging diagnosis of bile duct hamartomas.

  13. Salivary Duct Cyst: Histo-pathologic Correlation

    Divya Vinayachandran


    Full Text Available Non-neoplastic cysts of the salivary glands are uncommon and represent 2-5% of all salivary gland lesions. They are mainly mucoceles or salivary duct cysts. Unlike a mucocele, which is surrounded by granulation tissue, the salivary duct cyst is lined by epithelium. Salivary duct cysts are more common in the oral minor salivary glands and rarely occur in the major salivary glands, show a marked predilection for the superficial lobe of the parotid, and represent 10% of all salivary gland cysts. Neoplastic differentiation of the lining of the salivary duct cyst has been reported. We report a case of a salivary duct cyst of the left parotid gland, with a review of radiographic and histopathologic features.

  14. Flow accelerated corrosion study in feeder pipes

    Goyal, P.; Verma, V.; Singh, R.K. [Bhabha Atomic Research Centre, Mumbai (India). Reactor Safety Div.


    The Indian Pressurized Heavy Water Reactor (PHWR) core consists of a number of horizontal channels containing nuclear fuel bundles. Parallel coolant channels are connected to Inlet and Outlet header through feeder pipes. Coolant from Reactor Inlet Header is distributed to the coolant channels and after removing heat combines at Reactor Outlet Header. Due to space constraints the feeder pipes are joined to the channel with one or two elbows close to the end fittings of the coolant channels. The carbon steel feeder pipes carry high temperature fluid at higher velocity and are liable to undergo Flow Accelerated Corrosion (FAC). In the recent inspection it has been found that feeders having double elbow are more susceptible to FAC on the intrados of second elbow. But it was found that in some of the elbows maximum thinning due to FAC was observed on the intrados of the first elbow. Hence to resolve this, effect of first bend orientation with respect of upstream direction has been studied. Two different approaches are used for predicting the FAC rate from calculated value of wall shear stress by CFD. One method is based on evaluating of wear rate using Colburn analogy and the other using an empirical equation between wear rate and shear stress. In Colburn analogy, mass transfer coefficient is evaluated by knowing shear stress and equilibrium concentration. For a case study, wall shear stress obtained from k-ε turbulence model was compared with k-ω SST turbulence model and no appreciable change in the wall shear stress has been found. Hence for subsequent analysis k-ε turbulence model was chosen because large mesh size near to the surface (first layer thickness) is permitted due to higher y{sup +} value.

  15. Design of deepwater HP/HT pipe-in-pipe flowlines crossing mega-furrows in the Gulf of Mexico

    Tang, Tianxi Andy; Chacko, Jacob; Zhou, Mengjuan Jane; Omonoji, Gabriel O. [TECHNIP USA, Houston, TX (United States); Eigbe, Uwa [INTECSEA, Houston, TX (United States)


    Two 12-mile long pipe-in-pipe (PIP) with HT/HP flow lines were recently designed for the Chinook offshore oil field in the Gulf of Mexico. The routes of the flow line of the Chinook crosses continuous mega-furrows at the water depth ranging from 8200 ft to 8800 ft. The design of the temperature and pressure of the flow lines were 250 deg F and 12,684 psi, respectively. The detailed finite element analysis was performed to predict flow line in-place behavior. The strain-based criterion of API RP 1111 was used where stresses were greater than allowable limits of the ASME B31.8 and found to be satisfactory. The fatigue analysis of the spans pipe subjected to Vortex Induced Vibration (VIV) showed the need for VIV mitigation measures. It was decided that the entire length of the flow lines crossing the mega-furrows should be stake. The analysis of the stake fatigue life of the flow lines resulted greater than the required 25 years service life. Further analysis was performed on the PIP system to optimize the centralizer spacing to sufficiently limit the buckling of inner pipe under operation conditions and prevent crushing of the insulation in the annulus. J-lay analysis of the installation determining the amount of the inner pipe pre-tensioning that was required to eliminate locked-in stresses in the inner and outer pipes. (author)

  16. Euler/Navier-Stokes Solvers Applied to Ducted Fan Configurations

    Keith, Theo G., Jr.; Srivastava, Rakesh


    Due to noise considerations, ultra high bypass ducted fans have become a more viable design. These ducted fans typically consist of a rotor stage containing a wide chord fan and a stator stage. One of the concerns for this design is the classical flutter that keeps occurring in various unducted fan blade designs. These flutter are catastrophic and are to be avoided in the flight envelope of the engine. Some numerical investigations by Williams, Cho and Dalton, have suggested that a duct around a propeller makes it more unstable. This needs to be further investigated. In order to design an engine to safely perform a set of desired tasks, accurate information of the stresses on the blade during the entire cycle of blade motion is required. This requirement in turn demands that accurate knowledge of steady and unsteady blade loading be available. Aerodynamic solvers based on unsteady three-dimensional analysis will provide accurate and fast solutions and are best suited for aeroelastic analysis. The Euler solvers capture significant physics of the flowfield and are reasonably fast. An aerodynamic solver Ref. based on Euler equations had been developed under a separate grant from NASA Lewis in the past. Under the current grant, this solver has been modified to calculate the aeroelastic characteristics of unducted and ducted rotors. Even though, the aeroelastic solver based on three-dimensional Euler equations is computationally efficient, it is still very expensive to investigate the effects of multiple stages on the aeroelastic characteristics. In order to investigate the effects of multiple stages, a two-dimensional multi stage aeroelastic solver was also developed under this task, in collaboration with Dr. T. S. R. Reddy of the University of Toledo. Both of these solvers were applied to several test cases and validated against experimental data, where available.

  17. Study on Shock Wave and Turbulent Boundary Layer Interactions in a Square Duct at Mach 2 and 4

    Hiromu SUGIYAMA; Ryojiro MINATO; Kazuhide MIZOBATA; Akira TOJO; Yohei MUTO


    In this paper, the outline of the Mach 4 supersonic wind runnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.

  18. LHCb: Beam Pipe portrait

    LHCb, Collaboration


    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector: it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  19. LHCb: Beam Pipe

    LHCb, Collaboration


    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector:it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  20. Heat Pipe Systems


    Solar Fundamentals, Inc.'s hot water system employs space-derived heat pipe technology. It is used by a meat packing plant to heat water for cleaning processing machinery. Unit is complete system with water heater, hot water storage, electrical controls and auxiliary components. Other than fans and a circulating pump, there are no moving parts. System's unique design eliminates problems of balancing, leaking, corroding, and freezing.

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

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


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

  2. Pipe inspection using the pipe crawler. Innovative technology summary report



    The US Department of Energy (DOE) continually seeks safer and more cost-effective remediation technologies for use in the decontamination and decommissioning (D and D) of nuclear facilities. In several of the buildings at the Fernald Site, there is piping that was used to transport process materials. As the demolition of these buildings occur, disposal of this piping has become a costly issue. Currently, all process piping is cut into ten-foot or less sections, the ends of the piping are wrapped and taped to prevent the release of any potential contaminants into the air, and the piping is placed in roll off boxes for eventual repackaging and shipment to the Nevada Test Site (NTS) for disposal. Alternatives that allow for the onsite disposal of process piping are greatly desired due to the potential for dramatic savings in current offsite disposal costs. No means is currently employed to allow for the adequate inspection of the interior of piping, and consequently, process piping has been assumed to be internally contaminated and thus routinely disposed of at NTS. The BTX-II system incorporates a high-resolution micro color camera with lightheads, cabling, a monitor, and a video recorder. The complete probe is capable of inspecting pipes with an internal diameter (ID) as small as 1.4 inches. By using readily interchangeable lightheads, the same system is capable of inspecting piping up to 24 inches in ID. The original development of the BTX system was for inspection of boiler tubes and small diameter pipes for build-up, pitting, and corrosion. However, the system is well suited for inspecting the interior of most types of piping and other small, confined areas. The report describes the technology, its performance, uses, cost, regulatory and policy issues, and lessons learned.

  3. Application of the linear load normalization technique in specimens SE(T) for the evaluation of structural integrity in conducting ducts of gas and oil; Aplicacao da tecnica de normalizacao linear da carga em especimes SE(T) para a avaliacao de integridade estrutural em dutos condutores de gas e petroleo

    Piovatto, R.R.; Carvalho, A.L.M.; Bose Filho, W.W.; Spinelli, D.; Rugieri, C. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil); Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica], e-mail:


    This aim of this work is to evaluate the fracture toughness of pipe lines under high internal pressure, used in the petroliferous industry for transportation of gas and oil. These ducts are produced from high strength low alloy steels, classified as API X60. Therefore, to simulate the stress and strain fields ahead of crack, the SE(T) specimens has been point out as the best specimen geometry. The linear load normalization technique, LLN, has been showed as a promissory technique for obtaining the J-R resistance curves. The J values were obtained following the ASTM 1820 and 1152 standards, with the coefficients modified for this specimen geometry. Side groves were executed to avoid crack tunneling and to maintaining the crack on the plane perpendicular to the loading direction. The J-R curves obtained are compatible for high ductility steels. However, the observed J values seems to high, and the factors affecting this result are discussed in this work. (author)

  4. Some Comments on the Entropy-Based Criteria for Piping

    Emöke Imre


    Full Text Available This paper is an extension of previous work which characterises soil behaviours using the grading entropy diagram. The present work looks at the piping process in granular soils, by considering some new data from flood-protection dikes. The piping process is divided into three parts here: particle movement at the micro scale to segregate free water; sand boil development (which is the initiation of the pipe, and pipe growth. In the first part of the process, which occurs during the rising flood, the increase in shear stress along the dike base may cause segregation of water into micro pipes if the subsoil in the dike base is relatively loose. This occurs at the maximum dike base shear stress level (ratio of shear stress and strength zone which is close to the toe. In the second part of the process, the shear strain increment causes a sudden, asymmetric slide and cracking of the dike leading to the localized excess pore pressure, liquefaction and the formation of a sand boil. In the third part of the process, the soil erosion initiated through the sand boil continues, and the pipe grows. The piping in the Hungarian dikes often occurs in a two-layer system; where the base layer is coarser with higher permeability and the cover layer is finer with lower permeability. The new data presented here show that the soils ejected from the sand boils are generally silty sands and sands, which are prone to both erosion (on the basis of the entropy criterion and liquefaction. They originate from the cover layer which is basically identical to the soil used in the Dutch backward erosion experiments.

  5. An eddy viscosity calculation method for a turbulent duct flow

    Antonia, R. A.; Bisset, D. K.; Kim, J.


    The mean velocity profile across a fully developed turbulent duct flow is obtained from an eddy viscosity relation combined with an empirical outer region wake function. Results are in good agreement with experiments and with direct numerical simulations in the same flow at two Reynolds numbers. In particular, the near-wall trend of the Reynolds shear stress and its variation with Reynolds number are similar to those of the simulations. The eddy viscosity method is more accurate than previous mixing length or implicit function methods.

  6. Unusual scintigraphic appearance of perforation of the common bile duct

    Acevedo, M.O.; Tauxe, W.N.; Scott, J.W.; Aldrete, J.S.


    This report deals with the diagnosis of perforation of the common bile duct into the lesser sac by HIDA cholescintigraphy. The first hour images after injection were suggestive of biliary obstruction. Subsequent images demonstrated unusual accumulations of the activity into the lesser sac and retroperitoneal potential spaces. Careful correlation between scintigraphic and surgical findings were undertaken. The case is reported to demonstrate the scintigraphic findings in choledochal perforation and to stress the importance of carrying out late images when the initial ones are abnormal.

  7. Bile Duct Adenoma with Oncocytic Features

    E. J. Johannesen


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

  8. 46 CFR 76.33-15 - Piping.


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.33-15 Section 76.33-15 Shipping COAST GUARD... System, Details § 76.33-15 Piping. (a) Individual pipes shall be not less than 3/4-inch standard pipe size. (b) All piping, valves, and fittings of ferrous materials shall be protected inside and...

  9. Experimenting with a ``Pipe'' Whistle

    Stafford, Olga


    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here allows students in a physics of music or introductory physics course to study an example of an "edge tone" device that produces discrete sound frequencies. From their textbooks, students likely know about standing waves produced by pipes or strings, as well as the resonant frequencies for open and closed pipes. To go a bit further, they can also learn how the frequency of the sound wave depends on the orifice-to-edge distance of the wind instrument.

  10. Stress

    ... diabetes. Your Stress-Free System for Family Dinners! - 2017-03-book-oclock-scramble.html Your Stress-Free System for Family Dinners! A year of delicious meals to help prevent ...

  11. Stress

    ... sudden negative change, such as losing a job, divorce, or illness Traumatic stress, which happens when you ... stress, so you can avoid more serious health effects. NIH: National Institute of Mental Health

  12. Paraurethral Skene's duct cyst in a newborn

    Moralioğlu, Serdar; Bosnalı, Oktav; Celayir, Ayşenur Cerrah; Şahin, Ceyhan


    Paraurethral or Skene's duct cysts are rare causes of interlabial masses in neonates. The diagnosis of Skene's duct cysts in the neonatal period is based on its location, in relation to the urethra, and the demonstration of transitional epithelium in the cyst wall. The distinguishing features of paraurethral cysts are the displacement of urethral meatus by the mass and a cyst containing milky fluid. Thus, we report a case of a Skene's duct cyst in a newborn which was treated by incision and drainage. PMID:24049387

  13. Comparative study of approaches to estimate pipe break frequencies

    Simola, K.; Pulkkinen, U.; Talja, H.; Saarenheimo, A.; Karjalainen-Roikonen, P. [VTT Industrial Systems (Finland)


    The report describes the comparative study of two approaches to estimate pipe leak and rupture frequencies for piping. One method is based on a probabilistic fracture mechanistic (PFM) model while the other one is based on statistical estimation of rupture frequencies from a large database. In order to be able to compare the approaches and their results, the rupture frequencies of some selected welds have been estimated using both of these methods. This paper highlights the differences both in methods, input data, need and use of plant specific information and need of expert judgement. The study focuses on one specific degradation mechanism, namely the intergranular stress corrosion cracking (IGSCC). This is the major degradation mechanism in old stainless steel piping in BWR environment, and its growth is influenced by material properties, stresses and water chemistry. (au)

  14. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    Alani, Amir M; Faramarzi, Asaad


    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  15. Project W-320, 241-C-106 sluicing: Piping calculations. Volume 4

    Bailey, J.W.


    This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objective of this calculation is to perform the structural analysis of the Pipe Supports designed for Slurry and Supernate transfer pipe lines in order to meet the requirements of applicable ASME codes. The pipe support design loads are obtained from the piping stress calculations W320-27-I-4 and W320-27-I-5. These loads are the total summation of the gravity, pressure, thermal and seismic loads. Since standard typical designs are used for each type of pipe support such as Y-Stop, Guide and Anchors, each type of support is evaluated for the maximum loads to which this type of supports are subjected. These loads are obtained from the AutoPipe analysis and used to check the structural adequacy of these supports.

  16. Real-time corrosion control system for cathodic protection of buried pipes for nuclear power plant

    Kim, Ki Tae; Kim, Hae Woong; Kim, Young Sik [School of Materials Science and Engineering, Andong National University, Andong (Korea, Republic of); Chang, Hyun Young; Lim, Bu Taek; Park, Heung Bae [Power Engineering Research Institute, KEPCO Engineering and Construction Company, Seongnam (Korea, Republic of)


    Since the operation period of nuclear power plants has increased, the degradation of buried pipes gradually increases and recently it seems to be one of the emerging issues. Maintenance on buried pipes needs high quality of management system because outer surface of buried pipe contacts the various soils but inner surface reacts with various electrolytes of fluid. In the USA, USNRC and EPRI have tried to manage the degradation of buried pipes. However, there is little knowledge about the inspection procedure, test and manage program in the domestic nuclear power plants. This paper focuses on the development and build-up of real-time monitoring and control system of buried pipes. Pipes to be tested are tape-coated carbon steel pipe for primary component cooling water system, asphalt-coated cast iron pipe for fire protection system, and pre-stressed concrete cylinder pipe for sea water cooling system. A control system for cathodic protection was installed on each test pipe which has been monitored and controlled. For the calculation of protection range and optimization, computer simulation was performed using COMSOL Multiphysics (Altsoft co.)

  17. Multileg Heat-Pipe Evaporator

    Alario, J. P.; Haslett, R. A.


    Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

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

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


    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.

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

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


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

  20. Brittle fracture in casing pipes; Sproeda brott i mantelroer

    Nilsson, Stefan; Thoernblom, Kristian; Saellberg, Sven-Erik; Bergstroem, Gunnar [Swedish National Testing and Research Inst., Goeteborg (Sweden)


    Rapid Crack Propagation (RCP) has been observed in the casing pipe of large diameter district heating pipes on several occasions. An RCP crack is driven by hoop stresses in the casing pipe wall. It is a problem during installation work in cold weather. The casing pipe material is more brittle in low temperatures, and a temperature decrease will cause a hoop stress build-up since the thermal contraction of the casing pipe is constrained by the steel pipe and the PUR foam. RCP fracture has been documented at temperatures around -18 deg C but has likely, at some instances, occurred already at few degrees below 0 deg C. Three different polyethylene materials were evaluated with respect to the risk for brittle fracture of the casing pipe. One unimodal material of PE80 quality which have been used in casing to a large extent previously, one modern unimodal PE80 material which is used today and, finally, a bimodal PE80 material of a quality which currently is the dominant choice among pipe producers. Modern materials are in general much more resistant to brittle fracture, since it is an important design property for the raw material producers. Tests were done on casing of both large (up to 630 mm in diameter) and small (160 mm) dimension. A handling test was made where the pipes were cooled down and worked on with power tools in a manner similar to actual field work. An RCP fracture occurred at -25 deg C during cutting with angle grinder on a pipe with a diameter of 500 mm on the modern unimodal PE80 material. The same material also fractured during impact testing according to EN 253 at -20 deg C on both small and large diameter pipes. The bimodal PE80 resin passed both tests without fracture. A series of impact tests were done on pipes with diameter 160 mm with the purpose of determining critical temperatures and temperature stress levels with respect to brittle fracture. The results show that the bimodal material is so resistant that there is no real risk for RCP in

  1. Transmission of wave energy in curved ducts

    Rostafinski, W.


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

  2. Ducted propagation of chorus waves: Cluster observations

    K. H. Yearby


    Full Text Available Ducted propagation of whistler waves in the terrestrial magnetosphere-ionosphere system was discussed and studied long before the first in-situ spacecraft measurements. While a number of implicit examples of the existence of ducted propagation have been found, direct observation of ducts has been hampered by the low sampling rates of measurements of the plasma density. The present paper is based on Cluster observations of chorus waves. The ability to use measurements of the spacecraft potential as a proxy for high time resolution electron density measurements is exploited to identify a number of cases when increased chorus wave power, observed within the radiation belts, is observed simultaneously with density enchantments. It is argued that the observation of ducted propagation of chorus implies modification of numerical models for plasma-wave interactions within the radiation belts.

  3. General Information about Extrahepatic Bile Duct Cancer

    ... duct cancer include jaundice and pain in the abdomen. These and other signs and symptoms may be ... Dark urine . Clay colored stool . Pain in the abdomen . Fever . Itchy skin. Nausea and vomiting . Weight loss ...

  4. Treatment Options for Extrahepatic Bile Duct Cancer

    ... duct cancer include jaundice and pain in the abdomen. These and other signs and symptoms may be ... Dark urine . Clay colored stool . Pain in the abdomen . Fever . Itchy skin. Nausea and vomiting . Weight loss ...

  5. Stages of Extrahepatic Bile Duct Cancer

    ... duct cancer include jaundice and pain in the abdomen. These and other signs and symptoms may be ... Dark urine . Clay colored stool . Pain in the abdomen . Fever . Itchy skin. Nausea and vomiting . Weight loss ...

  6. Treatment Option Overview (Extrahepatic Bile Duct Cancer)

    ... duct cancer include jaundice and pain in the abdomen. These and other signs and symptoms may be ... Dark urine . Clay colored stool . Pain in the abdomen . Fever . Itchy skin. Nausea and vomiting . Weight loss ...


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


    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

  8. Effect of shear on duct wall impedance.

    Goldstein, M.; Rice, E.


    The solution to the equation governing the propagation of sound in a uniform shear layer is expressed in terms of parabolic cylinder functions. This result is used to develop a closed-form solution for acoustic wall impedance which accounts for both the duct liner and the presence of a boundary layer in the duct. The effective wall impedance can then be used as the boundary condition for the much simpler problem of sound propagation in uniform flow.

  9. Gas Explosions Mitigation by Ducted Venting


    The mitigation of effects of gas and dust explosions within industrial equipment is effective if venting the combustion products to safe location. The presence of relief duct is however likely to increase the severity of the explosion with respect to equipment vented to open atmosphere, due to secondary explosions occurring in the initial sections of duct, frictional drag and inertia of the gas column, acoustic and Helmholtz oscillations. The weights of these phenomena on explosion e...

  10. Energy Conservation Through Duct Leakage Reduction


    Energy Conservation Through Duct Leakage Reduction February 26, 2004 Rich Glatt – Lindab Inc. Report Documentation Page Form ApprovedOMB No. 0704...4. TITLE AND SUBTITLE Energy Conservation Through Duct Leakage Reduction 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Wall – DW that installs like SW - easiest installing DW system on the market – Eliminates the need for costly flanged connections – SMACNA Leakage

  11. Morbidity profile of steel pipe production workers

    Pandit Kirti


    Full Text Available Objective: To study the different morbid conditions among steel pipe producing workers. Methods: The present cross-sectional study has been carried out among the workers of one of the steel pipes and tubes manufacturing factory of Gujarat. Hundred workers from the four major departments of the steel pipe production plant, namely welding, pressing machine, X-ray welding and loading/transportation department were covered. The information regarding demographic, occupational, clinical characteristics and diagnosis were recorded on a pre-designed proforma. Statistical analysis included calculation of percentages and proportions and was carried out using the statistical software Epi Info Version 3.3.2. Results: The mean age of the study subjects was found to be 38.7±7.1 years. The mean duration of exposure was found to be 9.0±3.4 years. Forty-four percent of the subjects had an upper respiratory tract infection, as evidenced by symptoms like dry cough, cough with rhinitis and cough with fever. Symptoms suggestive of allergic bronchitis were observed in 12% of the subjects while symptoms suggestive of heat stress such as prickly heat, dehydration, perspiration and pyrexia were observed in 13% of the subjects.

  12. Fluid structure interaction in piping systems

    Svingen, Bjoernar


    The Dr. ing. thesis relates to an analysis of fluid structure interaction in piping systems in the frequency domain. The governing equations are the water hammer equations for the liquid, and the beam-equations for the structure. The fluid and structural equations are coupled through axial stresses and fluid continuity relations controlled by the contraction factor (Poisson coupling), and continuity and force relations at the boundaries (junction coupling). A computer program has been developed using the finite element method as a discretization technique both for the fluid and for the structure. This is made for permitting analyses of large systems including branches and loops, as well as including hydraulic piping components, and experiments are executed. Excitations are made in a frequency range from zero Hz and up to at least one thousand Hz. Frequency dependent friction is modelled as stiffness proportional Rayleigh damping both for the fluid and for the structure. With respect to the water hammer equations, stiffness proportional damping is seen as an artificial (bulk) viscosity term. A physical interpretation of this term in relation to transient/oscillating hydraulic pipe-friction is given. 77 refs., 72 figs., 4 tabs.

  13. Large-bore pipe decontamination

    Ebadian, M.A.


    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  14. Deployable Pipe-Z

    Zawidzki, Machi


    This paper presents a concept of deployable Pipe-Z (dPZ): a modular structural system which takes advantage of the robustness of rigid-panel mechanism and allows to create free-form links which are also reconfigurable and deployable. The concept presented can be applied for building habitats and infrastructures for human exploration of oceans and outer space. dPZ structures can adapt to changing requirements e.g. mission objectives, crew condition and technological developments. Furthermore, such lightweight and adaptable structural concept can assist in sustainable exploration development. After brief introduction, the concept of Pipe-Z (PZ) is presented. Next, the reconfigurability of PZ is explained and illustrated with continuous and collision-free transition from a PZ forming a Trefoil knot to a Figure-eight knot. The following sections introduce, explain and illustrate the folding mechanism of a single foldable Pipe-Z module (fPZM) and entire dPZ structure. The latter is illustrated with asynchronous (delayed) unfolding of a relatively complex Unknot. Several applications of PZ are suggested, namely for underwater and deep-space and surface habitats, for permanent, but in particular, temporary or emergency passages. As an example, a scenario of a failure of one of the modules of the International Space Station is presented where a rigid structure of 40 fPZMs bypasses the "dead link". A low-fidelity prototype of a 6-module octagonal dPZ is presented; several folding schemes including concentric toric rings are demonstrated. Practical issues of pressurization and packing are briefly discussed.

  15. Hydraulic resistance in part-full pipes with composite roughness

    Perrusquia, G.; Petersen, O.; Larsen, Torben


    The paper discusses the boundary shear stresses and the hydraulic resistance in part-full sewer pipes with composite roughness. The discussion is based on a series of numerical experiments using a validated numerical turbulence model. The results from the numerical model are compared...

  16. A methodology to evaluate the fatigue life of flexible pipes

    Sousa, Fernando J.M. de; Sousa, Jose Renato M. de; Siqueira, Marcos Q. de; Sagrilo, Luis V.S. [Coordenacao dos Programas de Pos-graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil); Lemos, Carlos Alberto D. de [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)


    This paper focus on a methodology to perform the fatigue analysis of flexible pipes. This methodology employs functions that convert forces and moments obtained in global analyses into stresses. The stresses are then processed by well-known cycle counting methods, and S-N curves evaluate the damage at several points in the pipe cross-section. Palmgren-Miner linear damage hypothesis is assumed in order to calculate the accumulated fatigue damage. A parametric study on the fatigue life of a flexible pipe employing this methodology is presented. The main points addressed in the study are the influence of friction between layers in the results, the importance of evaluating the fatigue life in various points of the pipe cross-section and the effect of different mean stress levels. The obtained results suggest that the consideration of friction effects strongly influences the fatigue life of flexible risers and these effects have to be accounted both in the global and local analyses of the riser. Moreover, mean stress effects are also significant and at least 8 equally spaced wires in each analyzed section of the riser must be considered in fatigue analyses. (author)

  17. Amputation neuroma mimics common hepatic duct carcinoma.

    Koike, N; Todoroki, T; Kawamoto, T; Inagawa, S; Yoshida, S; Fukao, K


    Most amputation neuromas of the biliary tract occur in the cystic duct stump after cholecystectomy and are asymptomatic. However, when they arise in the main hepatic duct and are associated with obstructive jaundice, it is difficult to distinguish them from carcinoma. We describe a case in which preoperative differential diagnosis was difficult. A 60-year-old man was admitted to the Institute of Clinical Medicine, University of Tsukuba, with a chief complaint of jaundice. Cholangiography showed an irregularly elevated nodular lesion on the lateral wall of the common hepatic duct and multiple floating stones in the choledochus. Ultrasonography and computed tomography revealed one-sided regional thickening of the common hepatic duct associated with dilatation of the intrahepatic and extrahepatic bile ducts. Carbohydrate antigen 19-9 level was markedly elevated to 11,200 IU/mL in the bile juice, but was only 38 IU/mL in the serum, below the limit of abnormality. Cholangioscopy showed papillary tumor with coarse granular surface mimicking papillary carcinoma, but biopsy revealed no malignancy. The patient underwent hepaticocholedochus resection. Although the macroscopic finding from the surgical specimens was papillary carcinoma of the common hepatic duct penetrating to the hepatoduodenal ligament, histopathological examination revealed an amputation neuroma consisting of hypertrophic nerve tissues and giant cells containing foreign bodies, probably as a consequence of a previous cholecystectomy. The postoperative course was uneventful and the patient has been living well for the 5 years since the resection.

  18. A Comparison of Simulation Capabilities for Ducts

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


    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. Double common bile duct: A case report

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


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



    ABSTRACTS WELDEL PIPE AND TUBE Vol.24 No.3 May.2001 Huang Jingan(1) Strengthen, Intercourse, Coordination and Promote the Development Together Liang Aiyu(11) The Production and the Development of the Water supply pipe for City Construction From the aspects of the quality, appearance, environment protection, economic analysis etc., This article evaluates the galvanized pipe, plastic steel complex pipe, plastic aluminum pipe, stainless pipe for city water supply. In accordance with the requirements of the city construction programming and development, it is considered that the plastic aluminum pipe and plastic steel pipe instead of galvanization pipe is the trend of the development. The author also gives some constructive proposals for reference. Subject Terms:galvanized pipe complex pipe stainless pipe city water supply evaluation Zhao Rongbin,Li Guangjun(14) The TIG welding of Protected Tantalum-pipe for sheathed thermocouples used in corrosive environment The protected Tantalum-pipe welding of sheathed therocouples was investigated by TIG. The welding process and its key parameters were introduced. Welding quality influenced by processing was discussed. Subject Terms:welding protected Tantalum-pipe corrosion He Defu et al(18) Design and Research for An Automatic MIG Welding Machine of Catalyst Converter of Automobile Two different schemes for automatic MIG welding of catalyst converter of automobile have been compared and analysed. A design of automatic MIG welding machine used for catalyst converter of automobile has been suggested in this paper. Subject Terms:environmental protection automobile tri-catalyst converter MIG welding automatic welding PLC Fang Chucai(24) Cold Crack Analysis of Low Alloy High Strength Steel Weld Seam Heat Affected Area During the welding of low alloy high strength (X65 and above), the fine crack occurs in the weld (especially inner weld) and the low plastic hard brickle structure occurs in the Heat Affected Area (HAZ) sometime. This

  1. Heat Pipe Blocks Return Flow

    Eninger, J. E.


    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  2. Mechanical Behaviour of Lined Pipe

    Hilberink, A.


    Installing lined pipe by means of the reeling installation method seems to be an attractive combination, because it provides the opportunity of eliminating the demanding welds from the critical time offshore and instead preparing them onshore. However, reeling of lined pipe is not yet proven

  3. Temperature drops in heat pipes

    Saatci, A.M.; Khalifa, A.M.A.; Akyurt, M.


    The role of entrainment in limiting heat pipe power handling capacity is discussed. The effect of entrainment on the measured temperature field in the integral heat pipe of a split system solar cooker is analyzed. An experimental set-up depicting a heat loop is presented, along with test results.

  4. Promethus Hot Leg Piping Concept

    AM Girbik; PA Dilorenzo


    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  5. Predicting Turbulent Convective Heat Transfer in Three-Dimensional Duct Flows

    Rokni, M.; Gatski, T. B.


    The performance of an explicit algebraic stress model is assessed in predicting the turbulent flow and forced heat transfer in straight ducts, with square, rectangular, trapezoidal and triangular cross-sections, under fully developed conditions over a range of Reynolds numbers. Iso-thermal conditions are imposed on the duct walls and the turbulent heat fluxes are modeled by gradient-diffusion type models. At high Reynolds numbers (>/= 10(exp 5)), wall functions are used for the velocity and temperature fields; while at low Reynolds numbers damping functions are introduced into the models. Hydraulic parameters such as friction factor and Nusselt number are well predicted even when damping functions are used, and the present formulation imposes minimal demand on the number of grid points without any convergence or stability problems. Comparison between the models is presented in terms of the hydraulic parameters, friction factor and Nusselt number, as well as in terms of the secondary flow patterns occurring within the ducts.

  6. Transduodenal exploration of the common bile duct in patients with nondilated ducts.

    Ratych, R E; Sitzmann, J V; Lillemoe, K D; Yeo, C J; Cameron, J L


    Exploration of the small common bile duct can be technically difficult and is associated with a significant risk of ductal injury or late stricture, or both. Transduodenal common duct exploration after sphincteroplasty (TCDE/S) is an alternative method of duct exploration that avoids choledochotomy. Cholecystectomy followed by TCDE/S was performed upon 28 patients with nondilated ducts and suspected choledocholithiasis. Common duct stones were retrieved in 17 patients. Failure to retrieve stones in the remaining 11 patients was attributed to either false-positive results of cholangiography, forceful passage of stones into the duodenum during the initial insertion of a Fogarty catheter through the cystic duct or a false-negative finding at duct exploration. There was no perioperative mortality. Two patients had asymptomatic postoperative hyperamylasemia. One patient had postoperative pancreatitis, hyperbilirubinemia and cholangitis that resolved with antibiotic therapy by the eighth postoperative day. Other complications included wound infection, delayed gastric emptying, pneumonia and otitis media. The over-all morbidity rate was 28.6 per cent. Long term follow-up was obtained in all 28 patients. All patients in the follow-up group are free of recurrent biliary tract disease. TCDE/S appears to be a safe and effective method of exploring the nondilated common bile duct.

  7. Ultrasound appearance of chronic mammary duct ectasia

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


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

  8. Effects of no stiffness inside unbonded tendon ducts on the behavior of prestressd concrete containment vessels

    Noh, Sang Hoon; Kwak, Hyo Gyong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Jung, Rae Young; Noh, Sang Hoon [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)


    The numerical simulation methodologies to evaluate the structural behaviors of prestressed concrete containment vessels (PCCVs) have been substantially developed in recent decades. However, there remain several issues to be investigated more closely to narrow the gap between test results and numerical simulations. As one of those issues, the effects of no stiffness inside unbonded tendon ducts on the behavior of PCCVs are investigated in this study. Duct holes for prestressing cables' passing are provided inside the containment wall and dome in one to three directions for general PCCVs. The specific stress distribution along the periphery of the prestressing duct hole and the loss of stiffness inside the hole, especially in an unbonded tendon system, are usually neglected in the analysis of PCCVs with the assumption that the duct hole is filled with concrete. However, duct holes are not small enough to be neglected. In this study, the effects of no stiffness inside the unbonded tendon system on the behaviors of PCCVs are evaluated using both analytical and numerical approaches. From the results, the effects of no stiffness in unbonded tendons need to be considered in numerical simulations for PCCVs, especially under internal pressure loading.

  9. Simulation of Welding of Thin-Walled Pipe

    Marek GEBAUER


    Full Text Available The presented paper deals with the residual stress after a welding operation performed by using the TIG method. It was necessary to determine whether or not tension plays a major role in the distortion of the geometry of a thin-walled pipe, or in other words, whether the drawing dimension of the ovality exceeds the specified tolerance. The result of this simulation will help to determine whether or not designers will have to find another technological solution to complete parts. The assembly consists of three parts: the weld bead, thin-walled pipe, and hoop, which are connected by welds as a final product.

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

    Mohan, H


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

  11. Structural evaluation report of piping and support structure for HANARO hot-water layer system

    Ryu, Jeong Soo


    The major goal of this report is to assess the structural integrity on the piping and the support structures of HANARO hot-water layer system. The piping stress analysis was performed by using ADLPIPE program for the pipings subjected to dead weight, pressure, thermal expansion and seismic loadings. The pipings to evaluate the structural integrity are the pump suction line and the pump discharge line near safety related structures in reactor pool. Based on the reaction forces from the piping stress analysis, the design of support structure was carried out. The results of structural evaluation for the piping and the support structure showed that the structural acceptance criteria were satisfied, in compliance with ASME B and PV code, section III, subsection ND for the pipings and Subsection NF for the support structures. Therefore based on results of the analysis and the design, the structural integrity on the piping and the support structures of HANARO hot-water layer system proved. (author). 9 tabs., 14 figs. 9 refs.

  12. Transurethral resection of the ejaculatory duct.

    Paick, J S


    Complete bilateral ejaculatory duct obstruction has long been recognized as an uncommon, treatable form of male infertility. Partial ejaculatory duct obstruction reflects a disturbance of ejaculation where sperm quality is impaired during transit through the distal vas deferens and ejaculatory ducts. With the advent and increased use of high-resolution transrectal ultrasonography, abnormalities of the distal ejaculatory ducts related to infertility have been well documented. Although there are no pathognomonic findings associated with ejaculatory duct obstruction, several clinical findings are highly suggestive. In an infertile man with oligospermia or azoospermia with low ejaculate volume, normal secondary sexual characteristics, testes and hormonal profile and dilated seminal vesicles, midline cyst, or calcification on transrectal ultrasonography, ejaculatory duct obstruction is suggested. Of course, other causes of infertility may be concomitantly present and need to be searched for and treated as well. In selected cases, transurethral resection has resulted in marked improvement in semen parameters and pregnancies have been achieved. As is the case with all surgical procedures, proper patient selection and surgical experience are necessary to obtain optimal results. However, it appears that the treatments currently available for relief of ejaculatory obstruction are not optimally effective. Only approximately one half of treated patients will have an improvement in semen parameters and only about one quarter of treated patients will contribute to a pregnancy. What remains to be determined is how to manage the additional nearly 50% of patients who do not benefit from transurethral resection of ejaculatory obstruction. Based on my experience, I suggest that transrectal ultrasonography should be the first diagnostic procedure used when infertile men are suspected of having ejaculatory duct obstruction; however, vasography should still be considered for a more

  13. Salivary duct carcinoma of the parotid gland

    Mona Mlika


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

  14. Numerical simulation of flow past circular duct

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


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

  15. Convolution seal for transition duct in turbine system

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


    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.

  16. Stress

    Keller, Hanne Dauer


    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  17. Stress

    Keller, Hanne Dauer


    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  18. 46 CFR 95.15-15 - Piping.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 95.15-15 Section 95.15-15 Shipping COAST GUARD... Dioxide Extinguishing Systems, Details § 95.15-15 Piping. (a) The piping, valves, and fittings shall have a bursting pressure of not less than 6,000 pounds per square inch. (b) All piping, in nominal...

  19. 46 CFR 154.520 - Piping calculations.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Piping calculations. 154.520 Section 154.520 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Process Piping Systems § 154.520 Piping calculations. A piping system must be designed to meet...

  20. 46 CFR 108.475 - Piping.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 108.475 Section 108.475 Shipping COAST GUARD... Extinguishing Systems Foam Extinguishing Systems § 108.475 Piping. (a) Each pipe, valve, and fitting in a foam... to remove liquid from the system. (e) Piping in a foam extinguishing system must be used only...

  1. 14 CFR 27.1123 - Exhaust piping.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust piping. 27.1123 Section 27.1123... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Exhaust System § 27.1123 Exhaust piping. (a) Exhaust piping... operating temperatures. (b) Exhaust piping must be supported to withstand any vibration and inertia loads...

  2. 46 CFR 197.336 - Pressure piping.


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that... must— (a) Meet the ANSI Code; (b) Have the point of connection to the integral piping system of...

  3. 46 CFR 64.95 - Piping.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping. 64.95 Section 64.95 Shipping COAST GUARD... SYSTEMS Cargo Handling System § 64.95 Piping. (a) Piping, valves, flanges, and fittings used in the... the piping system must comply with § 56.60-25(c) of this chapter....

  4. 46 CFR 76.23-20 - Piping.


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.23-20 Section 76.23-20 Shipping COAST GUARD... System, Details § 76.23-20 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements of subchapter F (Marine Engineering) of this chapter. (b) All piping, valves, and fittings...

  5. 46 CFR 95.17-15 - Piping.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD... Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements of Subchapter F (Marine Engineering) of this chapter. (b) All piping, valves, and fittings...

  6. 46 CFR 76.17-15 - Piping.


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD... Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements of subchapter F (Marine Engineering) of this chapter. (b) All piping, valves, and fittings...

  7. 46 CFR 193.15-15 - Piping.


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Piping. 193.15-15 Section 193.15-15 Shipping COAST GUARD... Dioxide Extinguishing Systems, Details § 193.15-15 Piping. (a) The piping, valves, and fittings shall have a bursting pressure of not less than 6,000 pounds per square inch. (b) All piping, in nominal...

  8. Investigation of high-frequency pipe welding

    Konovalov, Nikolai A.; Lakhno, Nikolay I.; Gushchin, A. G.; Putryk, N. D.; Kovalenko, Vladimir I.; Galkina, V. A.; Veselovsky, Vladimir B.; Furmanov, Valeri B.; Kovika, Nikolai D.; Novikov, Leonid V.; Shcherbina, V. N.


    For investigation of a pipe welding process at high-frequency heating aimed at increasing of pipe quality and decreasing of spoilage, the use of high-speed recording and TV-technique is considered to be effective. The authors have created a visual inspection system for pipe welding process studies at a tube mill of the Novomoskovsk Pipe Plant.

  9. 49 CFR 192.281 - Plastic pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  10. 49 CFR 195.114 - Used pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Used pipe. 195.114 Section 195.114 Transportation... PIPELINE Design Requirements § 195.114 Used pipe. Any used pipe installed in a pipeline system must comply with § 195.112 (a) and (b) and the following: (a) The pipe must be of a known specification and the...

  11. 49 CFR 195.112 - New pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false New pipe. 195.112 Section 195.112 Transportation... PIPELINE Design Requirements § 195.112 New pipe. Any new pipe installed in a pipeline system must comply with the following: (a) The pipe must be made of steel of the carbon, low alloy-high strength, or alloy...

  12. 49 CFR 192.55 - Steel pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for use...

  13. Loop Heat Pipe Startup Behaviors

    Ku, Jentung


    A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.

  14. Crack-tip constraints of through-wall cracked pipes and its similarity to curved wide plates

    Jang, Youn Young; Huh, Nam Su [Dept. of Mechanical System Design Engineering, Seoul National Univ. of Science and Technology, Seoul (Korea, Republic of); Jeong, Jae Uk [Global Turbine R and D Center, Doosan Heavy Industries and Construction, Changwon (Korea, Republic of); Kim, Ki Seok; Cho, Woo Yeon [Energy Infrastructure Research Group, Steel Solution Center, POSCO, Incheon (Korea, Republic of)


    In the present study, the effects of pipe geometries, material properties and loading conditions on crack-tip constraints of pipes with circumferential Through-wall crack (TWC) were investigated via systematic 3-dimensional (3-D) Finite element (FE) analyses. The crack-tip constraints were quantified by Q-stress, and to characterize the elastic-plastic strain hardening material behavior, Ramberg-Osgood (R-O) material was employed. Based on the FE results, it was observed that crack-tip constraints of pipes with TWC were dependent on crack length and thickness of pipe, however, the effects of each variables decreased as either thickness of pipe becomes thinner or crack length becomes longer. Moreover, the effects loading modes on Q-stresses for thin-walled pipes with TWC are negligible. Finally, the present Q-stresses of pipes were compared with those of Curved wide plate (CWP) in tension to address the similarity of crack-tip constraints between pipe and CWP, which could be used to produce the CWP to measure the fracture toughness of pipes accurately.

  15. Research and Practice on the Scheme of Pre-stressed Pipe Pile Reinforcing Multi-line Railway Subgrade%预应力管桩加固铁路多线路基的研究与实践

    陈效星; 朱洪伟


    verification were carried out. Research conclusions:(1 )Through the comparison of CFG pile raft,bored pile plate and pre-stressed pipe pile raft scheme,using pile raft for reinforcement multi line subgrade has obvious technical,economic and shorter work-period of comprehensive advantages.(2)By using the pile raft foundation,the amount of cushion compression,pile and the stab deformation of the piles can be ignored in the calculation of the settlement calculation of compositefoundation,the amount of compression of the substratum under the pile is only counted,calculation accuracy meets the requirements. (3)Using static pressure method for prestressed pipe pile construction,in case there are thick dense sand stratum,using high pressure water flushing with static pressure construction methods to traverse can meet the design pile depth. (4)Through observation and evaluation of subgrade settlement,it is recognized that using the pile raft foundation without preloading meet the standard of settlement after construction.(5 )The research results can provide reference for the foundation reinforcement of the multi line subgrade of passenger dedicated railway line.

  16. Nitrogen heat pipe for cryocooler thermal shunt

    Prenger, F.C.; Hill, D.D.; Daney, D.E.; Daugherty, M.A. [Los Alamos National Lab., NM (United States); Green, G.F.; Roth, E.W. [Naval Surface Warfare Center, Annapolis, MD (United States)


    A nitrogen heat pipe was designed, built and tested for the purpose of providing a thermal shunt between the two stages of a Gifford-McMahan (GM) cryocooler during cooldown. The nitrogen heat pipe has an operating temperature range between 63 and 123 K. While the heat pipe is in the temperature range during the system cooldown, it acts as a thermal shunt between the first and second stage of the cryocooler. The heat pipe increases the heat transfer to the first stage of the cryocooler, thereby reducing the cooldown time of the system. When the heat pipe temperature drops below the triple point, the nitrogen working fluid freezes, effectively stopping the heat pipe operation. A small heat leak between cryocooler stages remains because of axial conduction along the heat pipe wall. As long as the heat pipe remains below 63 K, the heat pipe remains inactive. Heat pipe performance limits were measured and the optimum fluid charge was determined.

  17. Acoustic energy in ducts - Further observations

    Eversman, W.


    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.

  18. Experimental strain measurements on large diameter mitered pipe joints

    Feier, Ioan I.; Leis, Brian N.; Zhu, Xian-Kui [Battelle Memorial Institute, Columbus, OH (United States); Stonesifer, Randall B. [Computational Mechanics Inc., Julian, PA (United States); Stavrakas, John S. [National Grid, Waltham, MA (United States); Eletto, Daniel D. [National Grid, Hicksville, NY (United States)


    Nowadays, small directional changes in a piping system are achieved by using cold field bent sections however, in the past, miter joints were used and so some pipelines still have such joints. The aim of this study was to determine the stress amplification due to miters in gas transmission pipelines. Experiments were carried out on X42 pipeline steel miter joints, 3 were taken from the Clove Lakes segment of the National grid system and 3 were manufactured for the test, all miter angles were between 0 and 8 degrees of total pipeline direction change; strain gauges were used to measure hoop and axial strains. Results showed that the stress increase due to miter joints increases linearly with the miter angle; in addition it was found that miters on the studied pipeline did not compromise its integrity. This study provided a good understanding of miter induced stress but results are limited to pipe with r/t values of 30.

  19. Xylometazoline hydrochloride nasal spray combined with laser artificial nasolacrimal duct implantation for nasolacrimal duct obstruction

    Xiao-Zhao Yang


    Full Text Available AIM: To study the role of xylometazoline hydrochloride nasal spray in combination therapy of nasolacrimal duct obstruction and to investigate the effect of nasal inflammation on nasolacrimal duct obstruction. METHODS: Totally 279 patients with nasolacrimal duct obstruction were collected, who received lacrimal passage irrigation, CT angiography for lacrimal passage and nasal endoscope before treated by lacrimal laser forming and artificial nasolacrimal duct implantation combined with xylometazoline hydrochloride nasal spray. In group A, 137 patients were treated with antibiotic eye drop and non-steroidal anti-inflammatory drugs after operations. In group B, 142 patients were treated with xylometazoline hydrochloride nasal spray besides the same treatment for group A. RESULTS:In the 279 patients 217(77.8%, in which 105 cases(76.6%were in group A and 112 cases(78.9%were in group B, were suffered with nasal inflammation, including nasal mucosal hyperemia, inferior turbinate hypertrophy, middle turbinate hypertrophy. At 3mo after the ducts were drawn, efficacy of group B was 95.8%, which was significant better than that of group A(86.1%, PCONCLUSION: Nasal inflammation was an important factor in the incidence of nasolacrimal duct obstruction, which shoud pay more attention in the process of diagnosis and treatment. Combination therapy could improve the cure rate of nasolacrimal duct obstruction.

  20. Percutaneous treatment of benign bile duct strictures

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


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

  1. Classiifcation of iatrogenic bile duct injur y

    Wan-Yee Lau; Eric C.H. Lai


    BACKGROUND: Iatrogenic bile duct injury continues to be an important clinical problem, resulting in serious morbidity, and occasional mortality, to patients. The ease of management, operative risk, and outcome of bile duct injuries vary considerably, and are highly dependent on the type of injury and its location. This article reviews the various classiifcation systems of bile duct injury. DATA SOURCES: A Medline, PubMed database search was performed to identify relevant articles using the keywords"bile duct injury", "cholecystectomy", and “classiifcation”. Additional papers were identiifed by a manual search of the references from the key articles. RESULTS: Traditionally, biliary injuries have been classiifed using the Bismuth's classiifcation. This classiifcation, which originated from the era of open surgery, is intended to help the surgeons to choose the appropriate technique for the repair, and it has a good correlation with the ifnal outcome after surgical repair. However, the Bismuth's classiifcation does not encompass the whole spectrum of injuries that are possible. Bile duct injury during laparoscopic cholecystectomy tends to be more severe than those with open cholecystectomy. Strasberg’s classiifcation made Bismuth’s classiifcation much more comprehensive by including various other types of extrahepatic bile duct injuries. Our group, Bergman et al, Neuhaus et al, Csendes et al, and Stewart et al have also proposed other classiifcation systems to complement the Bismuth's classiifcation. CONCLUSIONS:None of the classiifcation system is universally accepted as each has its own limitation. Hopefully, a universally accepted comprehensive classiifcation system will be published in the near future.

  2. 49 CFR 192.279 - Copper pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Copper pipe. 192.279 Section 192.279... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings or... heavier wall pipe listed in Table C1 of ASME/ANSI B16.5. [Amdt. 192-62, 54 FR 5628, Feb. 6, 1989, as...

  3. B Plant process piping replacement feasibility study

    Howden, G.F.


    Reports on the feasibility of replacing existing embedded process piping with new more corrosion resistant piping between cells and between cells and a hot pipe trench of a Hanford Site style canyon facility. Provides concepts for replacement piping installation, and use of robotics to replace the use of the canyon crane as the primary means of performing/supporting facility modifications (eg, cell lining, pipe replacement, equipment reinstallation) and operational maintenenace.

  4. Nonlinear acoustic propagation in rectangular ducts

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


    The method of multiple scales is used to obtain a second-order uniformly valid expansion for nonlinear acoustic wave propagation in a rectangular duct whose walls are treated with a nonlinear acoustic material. The wave propagation in the duct is characterized by the unsteady nonlinear Euler equations. The results show that nonlinear materials attenuate sound more than linear materials except at high acoustic frequencies. The nonlinear materials produce higher and combination tones which have higher attenuation rates than the fundamentals. Moreover, the attenuation rates of the fundamentals increase with increasing amplitude.

  5. Inverse potential scattering in duct acoustics.

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


    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.

  6. Preconditioning the Helmholtz Equation for Rigid Ducts

    Baumeister, Kenneth J.; Kreider, Kevin L.


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

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

    ... support? Along with these sample questions, be sure to write down some of your own. For instance, you ... Diagnosed? How is Bile Duct Cancer Staged? Survival Statistics for Bile Duct Cancers Resectable Versus Unresectable Bile ...

  8. Higher order mode propagation in nonuniform circular ducts

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


    This paper presents an analytical investigation of higher order mode propagation in a nonuniform circular duct without mean flow. An approximate wave equation is derived on the assumptions that the duct cross section varies slowly and that mode conversion is negligible. Exact closed form solutions are obtained for a particular class of converging-diverging circular duct which is here referred to as 'circular cosh duct'. Numerical results are presentd in terms of the transmission loss for the various duct shapes and frequencies. The results are applicable to studies of multimodal propagation as well as single mode propagation. The results are also applicable to studies of sound radiation from certain types of contoured inlet ducts, or of sound propagation in a converging-diverging duct of somewhat different shape from a cosh duct.

  9. Is spontaneous closure of a patent arterial duct common?

    Hoffman, Julien I E


    As closing a patent arterial duct is relatively simple, safe, and successful, most children with a patent arterial duct have it closed soon after diagnosis. The larger ducts are closed to prevent congestive heart failure, pulmonary vascular disease, or aneurysmal dilatation of the ductus, and smaller ducts are closed to prevent infective endocarditis. Consequently, there is no opportunity to determine whether spontaneous closure or diminution in size of the patent arterial duct is common. If the duct does become smaller, flow through it may be so low that no murmur is produced - the silent ductus. The frequency and best management of the silent patent arterial duct are unknown, and we do not know whether these tiny ducts are the last stage before spontaneous closure.

  10. Efficient methods of piping cleaning

    Orlov Vladimir Aleksandrovich; Nechitaeva Valentina Anatol'evna; Bogomolova Irina Olegovna; Shaykhetdinova Yuliya Aleksandrovna; Daminova Yuliya Farikhovna


    The article contains the analysis of the efficient methods of piping cleaning of water supply and sanitation systems. Special attention is paid to the ice cleaning method, in course of which biological foil and various mineral and organic deposits are removed due to the ice crust buildup on the inner surface of water supply and drainage pipes. These impurities are responsible for the deterioration of the organoleptic properties of the transported drinking water or narrowing cross-section of d...

  11. Stress

    Jensen, Line Skov; Lova, Lotte; Hansen, Zandra Kulikovsky; Schønemann, Emilie; Larsen, Line Lyngby; Colberg Olsen, Maria Sophia; Juhl, Nadja; Magnussen, Bogi Roin


    Stress er en tilstand som er meget omdiskuteret i samfundet, og dette besværliggør i en vis grad konkretiseringen af mulige løsningsforslag i bestræbelsen på at forebygge den såkaldte folkesygdom. Hovedkonklusionen er, at selv om der bliver gjort meget for at forebygge, er der ikke meget der aktivt kan sættes i værk for at reducere antallet af stressramte, før en fælles forståelse af stressårsager og effektiv stresshåndtering er fremlagt. Problemformuleringen er besvaret gennem en undersø...

  12. Corrosion behavior in heat pipe

    Anurak Rodbumrung


    Full Text Available The aim of this study was to perform life testing and determine the effect of working fluid on the corrosion of a heat pipe with a sintered wick. The heat pipe was made from a copper tube. The inner heat pipe was filled with 99.97% pure copper powder as a dendritic for the sintering process. The heat pipe had an outer diameter of 6 mm with a length of 200 mm, and distilled water and ethanol were the working fluids. The operating temperature at the evaporator was 125°C. The analysis consisted of using a scanning electron microscope, energy dispersive X-ray spectrometry and atomic absorption spectroscopy. The results of the scanning electron microscope and energy dispersive X-ray spectrometry analysis showed that the corrosion of the heat pipe was uniform. The result of the atomic absorption spectroscopy indicated that the concentration of the copper in the ethanol as the working fluid was greater than in the distilled water as the working fluid, and the highest concentration of copper particles in the ethanol was 22.7499 ppm or 0.0409 mg after testing for 3000 h. The concentration of copper was higher when the length of the life test increased due to corrosion of the heat pipe.

  13. Heat pipe turbine vane cooling

    Langston, L.; Faghri, A. [Univ. of Connecticut, Storrs, CT (United States)


    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and an uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  14. Algebraically growing waves in ducts with sheared mean flow

    Nayfeh, A. H.; Telionis, D. P.


    Analysis of the behavior of standing and traveling acoustic waves in a smooth duct with a fluid flow having a sheared mean velocity profile, when the waves grow algebraically as they travel along the duct axis. It is shown that standing waves growing algebraically with the axial distance cannot exist in a smooth duct when the duct wall have a finite resistance. The existence of traveling waves subject to the same law of growth is also dismissed under realistic flow conditions.

  15. Evaluation of aluminum drill-pipe material and design

    Placido, Joao C. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Lourenco, Marcelo I.; Netto, Theodoro Antoun [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)


    Experimental program and numerical analyses were carried out to investigate the fatigue mechanisms of aluminum drill pipes designed and manufactured in compliance with ISO 15546. The main objective is to improve the fatigue performance of these components by selecting the appropriate aluminum alloy and by enhancing the mechanical design of the threaded steel connector. This paper presents the experimental test program and numerical analyses conducted on a drill-pipe of different materials (Al-Cu-Mg and Al-Zn-Mg system aluminum alloys) and geometry. Material mechanical properties, including S-N curve, were determined through small-scale tests on specimens cut from actual drill pipes. Full-scale experiments were also performed in laboratory. A finite element model of the drill pipe, including the tool-joint region, was developed. The model simulates, through different load steps, the tool-joint hot assembly, and then reproduces the physical experiments numerically in order to obtain the actual stress distribution. Good correlation between full-scale and small-scale fatigue tests was obtained by adjusting the strain/stress levels monitored in the full-scale tests in light of the numerical simulations and performing fatigue life calculations via multiaxial fatigue models. The weak points of the current practice design are highlighted for further development. (author)

  16. Laser-guided repair of complex bile duct strictures.

    Gulik, T. van; Beek, J.; Reuver, P. de; Aronson, D.C.; Delden, O. van; Busch, O.; Gouma, D.


    BACKGROUND: The repair of bile duct strictures (BDS) requires identification of healthy bile duct proximal to the stenosis. Identification may be difficult in complex bile duct injuries after cholecystectomy or partial liver resection. AIM: We describe a technique to identify the prestenotic bile du

  17. Persistent Mullerian Duct Syndrome (PMDS With Large Intraabdominal Seminoma

    Della Harigovind


    Full Text Available Persistent Mullerian Duct Syndrome, a form of male pseudohermaphroditism is characterized by the presence of the Mullerian duct derivatives in an otherwise phenotypically as well as genotypically normal male. We report a case of large intra abdominal seminoma in a male patient with cryptorchidism, along with persistence of Mullerian duct derivatives (uterus.

  18. A case of fascioliasis in common bile duct

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


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


    ZHANG Ming-kan; SHEN Xin-rong; MA Jian-feng; ZHANG Ben-zhao


    The fully developed Oldroyd-B fluid flow through rotating square ducts was numerically studied. The effects of the rotation on secondary flow, axial velocity, and axial normal stress were examined in detail. The results indicated that all of the secondary flow, the axial flow, and the axial normal stress were evidently affected by the rotation. The Taylor-Proudman phenomenon could be observed in the flow. For the secondary flow, the four vortices structure and the six vortices structure were described. Recent studies also showed the effects of rotation on the axial normal stress.

  20. Surgical treatment of congenital biliary duct cyst

    Wang De-chun


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

  1. Idea Bank: Duct Tape Note Twister

    McHenry, Molly


    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…

  2. IDUS for Biliary and Pancreatic Duct Lesions

    Takao ltoi


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

  3. Calcium influx pathways in rat pancreatic ducts

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


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

  4. Laser Beam Duct Pressure Controller System.

    the axial flow of a conditioning gas within the laser beam duct, by matching the time rate of change of the pressure of the flowing conditioning the time rate of change of the pressure in the cavity of an operably associated laser beam turret.

  5. Familial occurrence of congenital bile duct dilatation


    Congenital bile duct dilatation (CBD) that developed in a parent and son is presented.Familial occurrence of CBD is rare,with only a few male cases having been reported.Since the initial report of CBD occurring in siblings in 1981,a total of 20 cases (10 pairs) have been published as of 2007.Clinical and genetic features of CBD are discussed.

  6. Strain Limits within the Scope of the Integrity Assessment of Piping Systems

    Mutz, Alexander [EnBW, Durlacher Allee 93, Karlsruhe 76131 (Germany)


    Allowable stresses in nuclear power plant piping resulting from loading conditions to be considered in Germany are determined on the basis of the German Safety Standards of the Nuclear Safety Standards Commission, KTA. The limitation of the different stress categories within the analysis of the mechanical behaviour is based on a linear elastic material behaviour. Because of the ductile material used in high energy nuclear piping, a more realistic assessment can be performed on the basis of allowable strains using elastic plastic material behaviour. In the present work comparison between the analysis of piping systems considering the elastic material model and the actual elastic plastic material behaviour is performed. The possibilities of allocating plastic strains to calculated elastic stresses is discussed. A parametric study on straight pipes with the actual elastic plastic material model under pure bending is the basis of deriving the elastic plastic strains for the calculated elastic stresses. Strain limits are suggested which correspond to the different stress categories. The aim is to utilize the deformation possibilities of ductile materials used in German nuclear piping and the allocation of maximum strains to different load categories. Keywords: strain limit, ductile material, stress category. (author)

  7. Investigation of the performance based structural safety factor of elbow pipes in nuclear power plants

    Lee, Sung Ho; Park, Chi Yong [Korea Electric Power Reserch Institute, Daejeon (Korea, Republic of); Park, Jai Hak [Chungbuk National University, Cheongju (Korea, Republic of)


    The piping systems in nuclear power plant are composed of various typed pipes such as straight pipe, elbow, branch and reducer etc. The elbow is connected from straight pipe to another pipes in order to establish the complicated piping system. Elbow is one of very important components considering management of wall thinning degradation. It is however applied by various loads such as system pressure, earthquake, postulated break loading and many transient loads, which provoke simply the internal pressure, bending and torsional stress. In this study, firstly pipes in the secondary system of the nuclear power plant are investigated in view of the ratio of radius to thickness. Next, a large number of finite element analysis considering the all typed dimensions of commercial pipe has been performed to find out the behavior of TES(Twice Elastic Slope) plastic load of elbows, which is based on evaluation of the structural safety factor. Finally performance based structural safety factor was investigated comparing with maximum allowable load by construction code.

  8. Elastoplastic pipe-soil interaction analyses of partially-supported jointed water mains

    Yu SHAO; Tu-qiao ZHANG


    Water distribution networks are essential components of water supply systems.The combination of pipe structural deterioration and mechanics leads to the failure of pipelines.A physical model for estimating the pipe failure must include both the pipe deterioration model and mechanics model.Winkler pipe-soil interaction(WPSI),an analytical mechanics model developed by Rajani and Tesfamariam(2004),takes external and internal loads,temperature changes,loss of bedding support,and the elastoplastic effect of soil into consideration.Based on the WPSI model,a method to evaluate the elastic and plastic areas was proposed in the present study.An FEM model based on pipe-soil interaction(PSI)element was used to verify the analytical model.Sensitivity analyses indicate that the soft soil,long pipe and high temperature induced the axial plastic deformation more likely,which,however,may not occur in normal scenarios.The soft soil,pipes in small diameters,long unsupported bedding are prone to form flexural plastic area.The results show that the pipes subjected to the same loads have smaller stresses in the elastoplastic analysis than elastic analysis.The difference,however,is slight.

  9. Heat Transfer in a Superelliptic Transition Duct

    Poinsatte, Philip; Thurman, Douglas; Hippensteele, Steven


    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. Effects of toughness anisotropy and combined tension, torsion, and bending loads on fracture behavior of ferritic nuclear pipe

    Mohan, R.; Marshall, C.; Ghadiali, N.; Wilkowski, G. [Battelle, Columbus, OH (United States)


    This paper summarizes work on angled through-wall-crack initiation and combined loading effects on ferritic nuclear pipe performed as part of the Nuclear Regulatory Commission`s research program entitled {open_quotes}Short Cracks In Piping an Piping Welds{close_quotes}. The reader is referred to Reference 1 for details of the experiments and analyses conducted as part of this program. The major impetus for this work stemmed from the observation that initially circumferentially oriented cracks in carbon steel pipes exhibited a high tendency to grow at a different angle when the cracked pipes were subjected to bending or bending plus pressure loads. This failure mode was little understood, and the effect of angled crack grown from an initially circumferential crack raised questions about how cracks in a piping system subjected to combined loading with torsional stresses would behave. There were three major efforts undertaken in this study. The first involved a literature review to assess the causes of toughness anisotropy in ferritic pipes and to develop strength and toughness data as a function of angle from the circumferential plane. The second effort was an attempt to develop a screening criterion based on toughness anisotropy and to compare this screening criterion with experimental pipe fracture data. The third and more significant effort involved finite element analyses to examine why cracks grow at an angle and what is the effect of combined loads with torsional stresses on a circumferentially cracked pipe. These three efforts are summarized.

  11. Radiant heating tests of several liquid metal heat-pipe sandwich panels

    Camarda, C. J.; Basiulis, A.


    Integral heat pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat load levels. The heat pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low distortion large area structures (e.g., space antennas) and laser mirrors.

  12. Improved collapse resistance of large diameter pipe for deepwater applications using a new impander technology

    Reichel, Thilo; Pavlyk, Vitaliy; Beissel, Jochem [Eisenbau Kramer GmbH, Kreutztal-Kredenbach, (Germany); Kyriakides, Stelias; Jang, Wen-Yea [The University of Texas at Austin, Austin, TX, (United States)


    The UOE and JCO processes are usually used to design pipes larger than 16 inches. The reduced collapse pressures are caused by the cold forming process used during these processes. This paper investigated a new manufacturing process in which longitudinally welded pipe formed by the JCO process is finished by controlled compression using a new cold sizing press called the Impander. Various rings have been evaluated to measure the dimensional and mechanical properties performed by this new compression process. Dimensional measurements were measured using calipers, micrometers and later a custom scanning system. The results showed that the compression improved the circularity of the pipe. The mechanical properties were measured by bending residual stress tests and a custom numerical model BEPTICO was used for evaluating the collapse pressure. It is found that this new process reduces the residual stresses of the pipe and improves its straightness.

  13. Evidence of sublaminar drag naturally occurring in a curved pipe

    Noorani, A.; Schlatter, P.


    Steady and unsteady flows in a mildly curved pipe for a wide range of Reynolds numbers are examined with direct numerical simulation. It is shown that in a range of Reynolds numbers in the vicinity of Reb ≈ 3400, based on bulk velocity and pipe diameter, a marginally turbulent flow is established in which the friction drag naturally reduces below the laminar solution at the same Reynolds number. The obtained values for friction drag for the laminar and turbulent (sublaminar) flows turn out to be in excellent agreement with experimental measurements in the literature. Our results are also in agreement with Fukagata et al. ["On the lower bound of net driving power in controlled duct flows," Phys. D 238, 1082 (2009)], as the lower bound of net power required to drive the flow, i.e., the pressure drop of the Stokes solution, is still lower than our marginally turbulent flow. A large-scale traveling structure that is thought to be responsible for that behaviour is identified in the instantaneous field. This mode could also be extracted using proper orthogonal decomposition. The effect of this mode is to redistribute the mean flow in the circular cross section which leads to lower gradients at the wall compared to the laminar flow.

  14. Effect of fluid/structure-interaction on pressure pulse loads on pipes

    Kellner, A.; Schoenfelder, C.


    In the analysis of pressure pulse loads on piping systems the fluid-structure-interaction is usually neglected. The resulting violation of energy conservation can lead to drastic overestimations of the loads. At first simple formulas are derived which can be used for a rough assessment of the magnitude of this effect for both possible forms of loads due to pressure waves: pipe wall stress and excitation of global pipe vibration. Secondly numerical methods which explicitly include the fluid-structure-interaction are described and some computational results presented.

  15. Mechanical Response of Steel Wire Wound Reinforced Rubber Flexible Pipe under Internal Pressure

    GU Fan; HUANG Cheng-kui; ZHOU Jing; LI Lin-pu


    Steel wire wound reinforced flexible pipe in this study mainly consists of multiple anisotropic steel wire wound reinforcement layers and multiple isotropic rubber layers. Based on 3D anisotropic elastic theory, the analytic solutions of stresses and elastic deformations of steel wire wound reinforced rubber flexible pipe under internal pressure are presented. As the adjacent reinforcement layers with wound angle have different radii, the single reinforcement layer shows the effect of tensile-shear coupling. Moreover, the static loading test results of steel wire wound reinforced rubber flexible pipe under internal pressure are basically coincided with the calculated values by present method.

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

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


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

  17. Magnetic resonance imaging of extrahepatic bile duct disruption

    Wong, Yon-Cheong; Wang, Li-Jen; Chen, Chi-Jen [Department of Radiology, Chang Gung Memorial Hospital, 5, Fu-Hsing Street, Gueishan, 33333 Taoyuan (Taiwan); Chen, Ray-Jade [Division of Trauma and Emergency Surgery, Chang Gung Memorial Hospital, 5, Fu-Hsing Street, Gueishan, 33333 Taoyuan (Taiwan)


    Blunt injury of the extrahepatic bile duct is rare and hence a large series of scientific study of its MRI is difficult to perform. We present the MRI and MR cholangiography of a case of blunt extrahepatic bile duct injury proven at surgery. The diagnosis could be established based on MRI findings of an abrupt tapering of the extrahepatic bile duct with a retracted end, a discordant small-caliber proximal duct, massive ascites, and a hematoma in proximity to the bile duct injury. This non-invasive MRI study is a promising imaging modality to evaluate biliary tract injury. (orig.)

  18. Performance Study and CFD Predictions of a Ducted Fan System

    Abrego, Anita I.; Chang, I-Chung; Bulaga, Robert W.; Rutkowski, Michael (Technical Monitor)


    An experimental investigation was completed in the NASA Ames 7 by 10-Foot Wind Tunnel to study the performance characteristics of a ducted fan. The goal of this effort is to study the effect of ducted fan geometry and utilize Computational Fluid Dynamics (CFD) analysis to provide a baseline for correlation. A 38-inch diameter, 10-inch chord duct with a five-bladed fixed-pitch fan was tested. Duct performance data were obtained in hover, vertical climb, and forward flight test conditions. This paper will present a description of the test, duct performance results and correlation with CFD predictions.

  19. Transition duct with divided upstream and downstream portions

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


    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.

  20. The Geometry Optimisation of a Triple Branch Pipe Using Finite Element Method

    Dorian Nedelcu


    Full Text Available The paper presents the geometrical optimization of a triple branch pipesubmitted to an internal pressure. The goal of the optimization was todetermine the optimum thickness of piping and branch pipe ribs, in thecondition of reaching admissible values of the stress and displacement.The resistance calculus was realized with Cosmos DesignStar softwareand the geometry was modeled with Microstation Modeler software.

  1. PIPEBOT: a mobile system for duct inspection

    Estrada, Emanuel; Goncalves, Eder Mateus; Botelho, Silvia; Oliveira, Vinicius; Souto Junior, Humberto; Almeida, Renan de; Mello Junior, Claudio; Santos, Thiago [Universidade Federal do Rio Grande (FURG), RS (Brazil); Gulles, Roger [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)


    In this paper, it is presented the development of an innovative and low-cost robotic mobile system to be employed in inspection of pipes. The system is composed of a robot with different sensors which permit to move inside pipes and detect faults as well as incipient faults. The robot is a semiautonomous one, i.e. it can navigate by human tele operation or autonomously one. The autonomous mode uses computer vision techniques and signals from position sensor of the robot to navigating and localizing it. It is showed the mechanical structure of the robot, the overall architecture of the system and preliminary results. (author)

  2. Application of the cracked pipe element to creep crack growth prediction

    Brochard, J.; Charras, T. [C.E.A.-C.E.-Saclay DRN/DMT, Gif Sur Yvette (France); Ghoudi, M. [C.E.A.-C.E.-Saclay, Gif Sur Yvette (France)


    Modifications to a computer code for ductile fracture assessment of piping systems with postulated circumferential through-wall cracks under static or dynamic loading are very briefly described. The modifications extend the capabilities of the CASTEM2000 code to the determination of fracture parameters under creep conditions. The main advantage of the approach is that thermal loads can be evaluated as secondary stresses. The code is applicable to piping systems for which crack propagation predictions differ significantly depending on whether thermal stresses are considered as primary or secondary stresses.

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

    D. L. Pasmanik


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

  4. Curved Duct Noise Prediction Using the Fast Scattering Code

    Dunn, M. H.; Tinetti, Ana F.; Farassat, F.


    Results of a study to validate the Fast Scattering Code (FSC) as a duct noise predictor, including the effects of curvature, finite impedance on the walls, and uniform background flow, are presented in this paper. Infinite duct theory was used to generate the modal content of the sound propagating within the duct. Liner effects were incorporated via a sound absorbing boundary condition on the scattering surfaces. Simulations for a rectangular duct of constant cross-sectional area have been compared to analytical solutions and experimental data. Comparisons with analytical results indicate that the code can properly calculate a given dominant mode for hardwall surfaces. Simulated acoustic behavior in the presence of lined walls (using hardwall duct modes as incident sound) is consistent with expected trends. Duct curvature was found to enhance weaker modes and reduce pressure amplitude. Agreement between simulated and experimental results for a straight duct with hard walls (no flow) was excellent.

  5. Rationale for Measuring Duct Leakage Flows in Large Commercial Buildings

    Wray, Craig P.; Diamond, Richard C.; Sherman, Max H.


    Industry-wide methods of assessing duct leakage are based on duct pressurization tests, and focus on ''high pressure'' ducts. Even though ''low pressure'' ducts can be a large fraction of the system and tend to be leaky, few guidelines or construction specifications require testing these ducts. We report here on the measured leakage flows from ten large commercial duct systems at operating conditions: three had low leakage (less than 5% of duct inlet flow), and seven had substantial leakage (9 to 26%). By comparing these flows with leakage flows estimated using the industry method, we show that the latter method by itself is not a reliable indicator of whole-system leakage flow, and that leakage flows need to be measured.

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

    Davis, Sanford


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

  7. Clinical effect of laparoscopic hepatolobectomy in patients with intrahepatic bile duct stones

    Pei Yu; Yan-Xia Zhong


    Objective:To study the clinical effect of laparoscopic hepatolobectomy in patients with intrahepatic bile duct stones. Methods:Patients with intrahepatic bile duct stones receiving hepatolobectomy were chosen for study, patients receiving laparoscopic surgery and patients receiving open surgery were screened and enrolled in laparoscopic group and open group respectively, and then degree of stress response, degree of liver damage and Nrf2-ARE signaling pathway function of two groups were compared. Results:At T1 and T2 points in time, stress indicators and Nrf2-ARE signaling pathway function of two groups had no difference;at T3 and T4 points in time, blood sugar, cortisol and angiotensin levels of laparoscopic group were lower, and insulin level as well as Nrf2 and ARE contents were higher;at T4 point in time, 8-OhdG, PCO, CYP1A and CYP3A contents of laparoscopic group were lower. Conclusion: Laparoscopic hepatolobectomy helps to relieve stress response, protect liver cells from damage and enhance Nrf2-ARE signaling pathway function;it’s an ideal method of surgical treatment of intrahepatic bile duct stones.

  8. 脉冲激光线源激发金属圆管中冯.密赛斯应力的研究%Analysis of the Von Mises stress fields generated by a pulsed line - source laser in metal pipes

    何跃娟; 朱云; 刘慧娟


    在得到的温茺场分布的基础上,用有限元结构分析法数值模拟了金属圆管中脉冲激光线源产生的主应力场情况,得到了铝管中不同时刻的冯.密赛斯应力场,给出了不同时刻冯,密赛斯应力随周向和法向的分布以及等值图分布情况。数值结果表明:在激光加载中心点处冯.密赛斯应力值最大,冯.密赛斯应力随周向和法向的变化情况和温度场的变化类似。%Based on the laser- induced temperature fields, the transient thermal stress fields generated by a pulsed line - source laser in aluminum pipe are analyzed by using a finite element method. The Van Mises stress fields are obtained at various time. The normal and the circmnferential distributions of Von Mises stress are given at various time. And the isolines' distributions of Von Mises stress are shown. The numerical results denoted: the center of the laser irradiation range at the material surface has the biggest Von Mises stress. The distribution of Von Mises stress is similar to the temperature distribution.

  9. Evaluation of burst pressure prediction models for line pipes

    Zhu, Xian-Kui, E-mail: [Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201 (United States); Leis, Brian N. [Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201 (United States)


    Accurate prediction of burst pressure plays a central role in engineering design and integrity assessment of oil and gas pipelines. Theoretical and empirical solutions for such prediction are evaluated in this paper relative to a burst pressure database comprising more than 100 tests covering a variety of pipeline steel grades and pipe sizes. Solutions considered include three based on plasticity theory for the end-capped, thin-walled, defect-free line pipe subjected to internal pressure in terms of the Tresca, von Mises, and ZL (or Zhu-Leis) criteria, one based on a cylindrical instability stress (CIS) concept, and a large group of analytical and empirical models previously evaluated by Law and Bowie (International Journal of Pressure Vessels and Piping, 84, 2007: 487-492). It is found that these models can be categorized into either a Tresca-family or a von Mises-family of solutions, except for those due to Margetson and Zhu-Leis models. The viability of predictions is measured via statistical analyses in terms of a mean error and its standard deviation. Consistent with an independent parallel evaluation using another large database, the Zhu-Leis solution is found best for predicting burst pressure, including consideration of strain hardening effects, while the Tresca strength solutions including Barlow, Maximum shear stress, Turner, and the ASME boiler code provide reasonably good predictions for the class of line-pipe steels with intermediate strain hardening response. - Highlights: Black-Right-Pointing-Pointer This paper evaluates different burst pressure prediction models for line pipes. Black-Right-Pointing-Pointer The existing models are categorized into two major groups of Tresca and von Mises solutions. Black-Right-Pointing-Pointer Prediction quality of each model is assessed statistically using a large full-scale burst test database. Black-Right-Pointing-Pointer The Zhu-Leis solution is identified as the best predictive model.

  10. Flat heat pipe design, construction, and analysis

    Voegler, G.; Boughey, B.; Cerza, M.; Lindler, K.W.


    This paper details the design, construction and partial analysis of a low temperature flat heat pipe in order to determine the feasibility of implementing flat heat pipes into thermophotovoltaic (TPV) energy conversion systems.

  11. A Model for Predicting the Yield Strength Difference between Pipe and Plate of Low-Carbon Microalloyed Steel

    Zhang, Wenlong; Ding, Dongyan; Gu, Mingyuan


    A combination of finite-element calculation and tension-compression tests was employed to predict the yield strength difference between the pipe and plate of low-carbon microalloyed steel (LCMS) in the production of high-frequency straight bead welding pipes (HFSBWPs). The deformation process was divided into bending, flattening, and tension deformations. The bending and flattening deformations were simulated using a finite-element method in order to obtain circumferential strains at pipe wall positions along the wall thickness. These strains were the transition strains in the subsequent tension-compression-tension and compression-tension tests. The yield stresses (0.5 pct proof stresses) at the pipe wall positions were derived from the obtained stress-strain curves. The average of the obtained yield stresses was taken as the predicted yield strength of the pipes. It is found that the difference between the latter and the strength of the original steel plates is a result of the combined action of the Bauschinger effect and strain hardening caused by bending and reverse bending deformations. It is strongly dependent on the ratio of pipe wall thickness to pipe outer diameter ( T/D ratio). At low T/D ratios, the Bauschinger effect was dominant, resulting in a decreased yield strength. Strain hardening due to work hardening was dominant at higher T/D ratios, resulting in an increased yield strength. The increase in yield strength was greater at the inner pipe walls than at outer ones, indicating that strain hardening is stronger at inner pipe walls. The yield strength differences predicted with the presented approach are comparable with the values obtained from industrial productions of HFSBWPs, indicating that this approach can be used to predict the yield strength difference between pipe and plate of LCMS.

  12. 46 CFR 61.15-5 - Steam piping.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a.... If the covering of the piping is not removed, the test pressure shall be maintained on the piping...

  13. 49 CFR Appendix B to Part 192 - Qualification of Pipe


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Qualification of Pipe B Appendix B to Part 192... Pipe I. Listed Pipe Specifications API 5L—Steel pipe, “API Specification for Line Pipe” (incorporated by reference, see § 192.7). ASTM A53/A53M—Steel pipe, “Standard Specification for Pipe, Steel Black...

  14. Acoustic Power Transmission Through a Ducted Fan

    Envia, Ed


    For high-speed ducted fans, when the rotor flowfield is shock-free, the main contribution to the inlet radiated acoustic power comes from the portion of the rotor stator interaction sound field that is transmitted upstream through the rotor. As such, inclusion of the acoustic transmission is an essential ingredient in the prediction of the fan inlet noise when the fan tip relative speed is subsonic. This paper describes a linearized Euler based approach to computing the acoustic transmission of fan tones through the rotor. The approach is embodied in a code called LINFLUX was applied to a candidate subsonic fan called the Advanced Ducted Propulsor (ADP). The results from this study suggest that it is possible to make such prediction with sufficient fidelity to provide an indication of the acoustic transmission trends with the fan tip speed.

  15. Theoretical analysis of HVAC duct hanger systems

    Miller, R. D.


    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.

  16. Introduction to Loop Heat Pipes

    Ku, Jentung


    This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.

  17. 46 CFR 169.652 - Bilge piping.


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Bilge piping. 169.652 Section 169.652 Shipping COAST... Electrical Bilge Systems § 169.652 Bilge piping. (a) All vessels of 26 feet in length and over must be... than 120 feet in length the bilge pipe must be not less than one and one-half inches. Piping on...

  18. China Steel Pipes Demand Rising Steadily


    @@ Steel pipes industry is an industry to play a decisive role in the national economic development. During the Tenth Five-Year Plan period, the steel pipes output has been increased distinctly. Based on experts forecast,the steel pipes demand in China will still be in tendency of increase during the Eleventh FiveYear Plan period, which will doubtlessly bring new opportunity and challenge to the steel pipes enterprises in China.

  19. 46 CFR 76.15-15 - Piping.


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.15-15 Section 76.15-15 Shipping COAST GUARD... Extinguishing Systems, Details § 76.15-15 Piping. (a) The piping, valves, and fittings shall have a bursting pressure of not less than 6,000 p.s.i. (b) All piping, in nominal sizes not over 3/4 inch, shall be...

  20. Assessment of the integrity of welded pipes

    Šarkoćević, Živče; Arsić, Miodrag; Sedmak, Aleksandar; MEĐO, Bojan; Mišić, Milan; id_orcid 0000-0003-0550-1851


    The subject of the paper is analysis of the integrity of welded pipes made of API J55 steel by high frequency contact welding (HF). Experimental research on the mechanical properties of the base material was conducted on pipes withdrawn from exploatation after 70 000 hours at service. Defect influence of the surface crack on the integrity of pipes was tested using hydrostatic pressure of pipes with axial surface crack in the base material. Fracture behaviour was tested using modified compact ...



    An experimental bimorph piezoelectric element (PZT) actuator for small pipe robot is developed. The robotcan move in φ 20 mm pipe, and can carry a CCD camera for detecting cracks or fine holes on inner surface of pipe. Thevelocity of the robot can reach 17~22 mm/s for vertical pipe up/down, respectively. Moving principle and its perfor-mance characteristics are presented.

  2. Analysis of Municipal Pipe Network Franchise Institution

    Yong, Sun; Haichuan, Tian; Feng, Xu; Huixia, Zhou

    Franchise institution of municipal pipe network has some particularity due to the characteristic of itself. According to the exposition of Chinese municipal pipe network industry franchise institution, the article investigates the necessity of implementing municipal pipe network franchise institution in China, the role of government in the process and so on. And this offers support for the successful implementation of municipal pipe network franchise institution in China.

  3. Extrahepatic bile duct neurilemmoma mimicking Klatskin tumor.

    Kamani, Fereshteh; Dorudinia, Atosa; Goravanchi, Farhood; Rahimi, Farzaneh


    Neurilemmoma rarely develops in the biliary tree. Here, we report a 39-year-old Iranian woman with neurilemmoma in the extrahepatic bile duct presenting with progressively deepening jaundice. On the basis of clinical and radiological features, this tumor was initially suspected as Klatskin tumor. Histologically, the tumor was a typical neurilemmoma. Immunostaining showed that tumor cells were strongly and diffusely positive for S-100 protein, which supported the diagnosis of neurilemmoma. Neurilemmoma should be considered in the differential diagnosis of obstructive jaundice.

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

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


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

  5. Endoscopic management of bile duct stones.

    Sivak, M V


    Endoscopic sphincterotomy is the procedure of choice for choledocholithiasis in patients who have had a cholecystectomy. The bile duct is cleared of stones in about 80 to 90 percent of patients. Available data, largely retrospective, suggest that surgery and endoscopic sphincterotomy are about equal with respect to removal of stones, morbidity, and mortality. Certain technical problems are discussed, including inability to insert the papillotome, the large stone, and problems relating to anatomy such as peripapillary diverticulum and prior gastrectomy. The treatment of patients with bile duct stones who have not had a cholecystectomy, with and without cholelithiasis, is controversial. Endoscopic sphincterotomy without subsequent cholecystectomy is adequate treatment for the majority of patients who are unfit for surgery, even if there are stones in the gallbladder, provided they are asymptomatic after endoscopic removal of stones from the bile ducts. Endoscopic sphincterotomy has been performed in the treatment of gallstone-induced pancreatitis, acute obstructive cholangitis, and sump syndrome. The complication rate for endoscopic sphincterotomy ranges from 6.5 to 8.7 percent, with a mortality rate of 0 to 1.3 percent. The most common serious complications are perforation, hemorrhage, acute pancreatitis, and sepsis.

  6. Endoscopic Management of Difficult Bile Duct Stones

    Christian Ell


    Full Text Available More than 90% of all common bile duct concrements can be removed via the endoscopic retrograde route via endoscopic sphincterotomy, stone extraction by baskets and balloon catheters, or mechanical lithotripsy. Oversized, very hard or impacted stones, however, often still resist conventional endoscopic therapy. Promising new or improved approaches for the treatment of these stones are intracorporeal or extracorporeal shock wave lithotripsy. Shockwave lithotriptors for extracorporeal shockwave lithotripsy are currently available worldwide. However, for the waterbath first generation devices, general anesthesia is required since shockwaves are very painful. Furthermore, an x-ray localization system is essential to visualize the stones after having filled the bile duct over a nasobiliary catheter. An average of two shockwave treatments with additional two to four endoscopic sessions are required. ln tracorporeal lithotripsy promises more comfort and less effort for the patient. Shockwaves are generated either by means of the spark gap principle (electrohydraulic probes or by laser-induced plasma generation. Laser-induced shockwave lithotripsy appears to be more safer, since with dye and solid state lasers, athermal, well-controlled shockwaves can be generateJ without the risks for duct perfo ration (as described for the electrohydraulic system. Furthermore, a recently developed stone-tissue detection system integrated in a new dye laser system enchances the safety of laser-induced lithotripsy. ln consequence, lithotripsy without direct endoscopic control appears possible in selected cases.

  7. Particle deposition in industrial duct bends.

    Peters, Thomas M; Leith, David


    A study of particle deposition in industrial duct bends is presented. Particle deposition by size was measured by comparing particle size distributions upstream and downstream of bends that had geometries and flow conditions similar to those used in industrial ventilation. As the interior surface of the duct bend was greased to prevent particle bounce, the results are applicable to liquid drops and solid particles where duct walls are sticky. Factors investigated were: (i) flow Reynolds number (Re = 203 000, 36 000); (ii) particle Reynolds number (10 vertical); and (vii) construction technique (smooth, gored, segmented). Measured deposition was compared with models developed for bends in small diameter sampling lines (Re 20 microm, deposition was slightly greater in the horizontal-to-horizontal orientation than in the horizontal-to-vertical orientation due to gravitational settling. Penetration was not a multiplicative function of bend angle as theory predicts, due to the developing nature of turbulent flow in bends. Deposition in a smooth bend was similar to that in a gored bend; however, a tight radius segmented bend (R0 = 1.7) exhibited much lower deposition. For more gradual bends (3 < R0 < 12), curvature ratio had negligible effect on deposition.

  8. MRI of the biliary and pancreatic ducts

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


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

  9. Smoking water pipe is injurious to lungs

    Sivapalan, Pradeesh; Ringbæk, Thomas; Lange, Peter


    This review describes the pulmonary consequences of water pipe smoking. Smoking water pipe affects the lung function negatively, is significantly associated with chronic obstructive pulmonary disease and increases the risk of lung infections. Case reports suggest that regular smokers of water pipe...

  10. 46 CFR 108.449 - Piping tests.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping tests. 108.449 Section 108.449 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.449 Piping tests. (a... piping installation. (b) When tested with CO2 or other inert gas under a pressure of 70 kilograms...

  11. 14 CFR 29.1123 - Exhaust piping.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust piping. 29.1123 Section 29.1123... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Exhaust System § 29.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to...

  12. 46 CFR 76.10-15 - Piping.


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.10-15 Section 76.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Fire Main System, Details § 76.10-15 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements...

  13. 49 CFR 195.128 - Station piping.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Station piping. 195.128 Section 195.128 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.128 Station piping. Any pipe to be installed in a station that...

  14. 46 CFR 193.10-15 - Piping.


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Piping. 193.10-15 Section 193.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS FIRE PROTECTION EQUIPMENT Fire Main System, Details § 193.10-15 Piping. (a) All piping, valves, and fittings, shall meet...

  15. 46 CFR 95.10-15 - Piping.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 95.10-15 Section 95.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Fire Main System, Details § 95.10-15 Piping. (a) All piping, valves, and fittings shall meet the...

  16. 14 CFR 25.1123 - Exhaust piping.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust piping. 25.1123 Section 25.1123... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant and auxiliary power unit installations, the following apply: (a) Exhaust piping must be heat...

  17. 46 CFR 132.110 - Piping.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 132.110 Section 132.110 Shipping COAST GUARD....110 Piping. (a) Except as provided for liftboats by § 134.180 of this subchapter, each fitting, flange, valve, and run of piping must meet the applicable requirements of part 128 of this subchapter....

  18. Thermodynamic aspects of heat pipe operation

    Richter, Robert; Gottschlich, Joseph


    An expanded heat pipe operating model is described which includes thermodynamic and heat transfer considerations to reconcile disparities between actual and theoretical heat pipe performances. The analysis shows that thermodynamic considerations can explain the observed heat pipe performance limitations. A full understanding of thermodynamic processes could lead to advanced concepts for thermal transport devices.

  19. 46 CFR 154.660 - Pipe welding.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...

  20. 49 CFR 192.59 - Plastic pipe.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  1. 49 CFR 236.712 - Brake pipe.


    ... 49 Transportation 4 2010-10-01 2010-10-01 false Brake pipe. 236.712 Section 236.712 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe...

  2. 46 CFR 76.25-30 - Piping.


    ..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where...

  3. 33 CFR 127.1101 - Piping systems.


    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Piping systems. 127.1101 Section... Waterfront Facilities Handling Liquefied Hazardous Gas Design and Construction § 127.1101 Piping systems. Each piping system within the marine transfer area for LHG used for the transfer of LHG must meet the...

  4. 46 CFR 56.10-5 - Pipe.


    ...) Ferrous pipe. ASTM Specification A 53 (incorporated by reference, see § 56.01-2) furnace welded pipe shall... found from Table 56.60-1(a). (3) Copper-nickel alloys may be used for water and steam service within the... specifically permitted by this part. (6) Aluminum-alloy pipe or tube along with similar junction equipment may...

  5. Thermal stress in SiC element used in heat exchanger

    LI He-song; MEI Chi


    An especial snake SiC pipe was designed for collecting losing heat from furnaces. The three-dimensions thermal, fluid and thermal stress coupled field of heat exchanger was analyzed by using the commercial engineering computer package ANSYS. The structural and operational parameters of heat exchanger, the junction between standpipe and snake pipe, the diameter of snake pipe, ratio of thickness to diameter of pipe, velocity of inlet air were optimized for thermal stress. The computed results show that the large thermal stress exits in the SiC, and the stand pipe should be ellipse for the least thermal stress; the optimal ratio of thickness to diameter of pipe is 6, the velocity of inlet air is 25 m/s. The most thermal stress is in inverse proportion to diameter of pipe and velocity of inlet air.

  6. PPOOLEX experiments with two parallel blowdown pipes

    Laine, J.; Puustinen, M.; Raesaenen, A. (Lappeenranta Univ. of Technology, Nuclear Safety Research Unit (Finland))


    This report summarizes the results of the experiments with two transparent blowdown pipes carried out with the scaled down PPOOLEX test facility designed and constructed at Lappeenranta University of Technology. Steam was blown into the dry well compartment and from there through either one or two vertical transparent blowdown pipes to the condensation pool. Five experiments with one pipe and six with two parallel pipes were carried out. The main purpose of the experiments was to study loads caused by chugging (rapid condensation) while steam is discharged into the condensation pool filled with sub-cooled water. The PPOOLEX test facility is a closed stainless steel vessel divided into two compartments, dry well and wet well. In the experiments the initial temperature of the condensation pool water varied from 12 deg. C to 55 deg. C, the steam flow rate from 40 g/s to 1 300 g/s and the temperature of incoming steam from 120 deg. C to 185 deg. C. In the experiments with only one transparent blowdown pipe chugging phenomenon didn't occur as intensified as in the preceding experiments carried out with a DN200 stainless steel pipe. With the steel blowdown pipe even 10 times higher pressure pulses were registered inside the pipe. Meanwhile, loads registered in the pool didn't indicate significant differences between the steel and polycarbonate pipe experiments. In the experiments with two transparent blowdown pipes, the steamwater interface moved almost synchronously up and down inside both pipes. Chugging was stronger than in the one pipe experiments and even two times higher loads were measured inside the pipes. The loads at the blowdown pipe outlet were approximately the same as in the one pipe cases. Other registered loads around the pool were about 50-100 % higher than with one pipe. The experiments with two parallel blowdown pipes gave contradictory results compared to the earlier studies dealing with chugging loads in case of multiple pipes. Contributing

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

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


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

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

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


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

  9. This is not a Pipe

    Just, Sine Nørholm


    or unwilling to listen to, let alone engage with, emotionally guided bottom-up participation. Using an illustrative case of a Danish public debate over an alleged ban on liquorice pipes, this article argues that the disconnect between invitation and participation may be explained by the fact...

  10. Investigation of sand in piping

    Nađ Laslo


    Full Text Available For the investigation of the grain size distribution of the material washed out from the piping, we used 20 samples originating from different places on the Danube and the Tisza rivers. The grading characteristics of these samples were investigated based on selected grain sizes and the uniformity of gradients. Based on the investigations it has become possible to identify which grain size fractions are likely to be washed out, and how to characterize those fractions. Based on the grain size distribution curves it has been made possible to define the boundaries of the zone susceptible to piping. The zone limits of granular soils liquefied by earthquakes and the zone limits of the soil out washed from piping are very similar. This apparent correspondence already formerly raised the hypothetic question of whether piping occurring during high flood can be simulated by shape to similar surface liquefaction phenomena experienced during earthquakes, as in both cases a volcanic cone is formed through the crater of which water is constantly issuing, dragging away solid particles.

  11. Localized turbulence in pipe flow

    Kuik, D.J.


    In this thesis the transition to turbulence in pipe flow is investigated. At low Reynolds numbers, the flow returns to the laminar state spontaneously. At high Reynolds number a small perturbation causes the flow to suddenly become turbulent. In the intermediate regime localized turbulence is observ

  12. Methods for Analyzing Pipe Networks

    Nielsen, Hans Bruun


    to formulate the flow equations in terms of pipe discharges than in terms of energy heads. The behavior of some iterative methods is compared in the initial phase with large errors. It is explained why the linear theory method oscillates when the iteration gets close to the solution, and it is further...

  13. Spinning pipe gas lens revisited

    Mafusire, C


    Full Text Available The graded index (GRIN-like) medium generated by gas inside a heated steel pipe when rotated about its longitudinal axis has the ability to focus a laser beam. While the effective focal length of such a system has previously been studied...

  14. Efficient methods of piping cleaning

    Orlov Vladimir Aleksandrovich


    Full Text Available The article contains the analysis of the efficient methods of piping cleaning of water supply and sanitation systems. Special attention is paid to the ice cleaning method, in course of which biological foil and various mineral and organic deposits are removed due to the ice crust buildup on the inner surface of water supply and drainage pipes. These impurities are responsible for the deterioration of the organoleptic properties of the transported drinking water or narrowing cross-section of drainage pipes. The co-authors emphasize that the use of ice compared to other methods of pipe cleaning has a number of advantages due to the relative simplicity and cheapness of the process, economical efficiency and lack of environmental risk. The equipment for performing ice cleaning is presented, its technological options, terms of cleansing operations, as well as the volumes of disposed pollution per unit length of the water supply and drainage pipelines. It is noted that ice cleaning requires careful planning in the process of cooking ice and in the process of its supply in the pipe. There are specific requirements to its quality. In particular, when you clean drinking water system the ice applied should be hygienically clean and meet sanitary requirements.In pilot projects, in particular, quantitative and qualitative analysis of sediments adsorbed by ice is conducted, as well as temperature and the duration of the process. The degree of pollution of the pipeline was estimated by the volume of the remote sediment on 1 km of pipeline. Cleaning pipelines using ice can be considered one of the methods of trenchless technologies, being a significant alternative to traditional methods of cleaning the pipes. The method can be applied in urban pipeline systems of drinking water supply for the diameters of 100—600 mm, and also to diversion collectors. In the world today 450 km of pipelines are subject to ice cleaning method.Ice cleaning method is simple

  15. Preliminary Design of IHTS Piping Support for PGSFR

    Kim, Nak-Hyun; Koo, Gyeong-Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    A pipe support is a designed element that transfer the load from pipe to the supporting structures. Providing sufficient pipe wall thickness and installing proper supports are most important elements for structural integrity of the piping system. Piping supports are generally referred to as device used in supporting the weight of the piping. The weight includes that of the pipe proper, the content the pipe carries, and the pipe converting, such as insulation. A FE analysis was performed to select variable spring hanger of IHTS hot-leg piping for PGSFR. The calculated values will be used to design variable spring hanger.

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

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


    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.

  17. Generation of Turbulent Inflow Conditions for Pipe Flow via an Annular Ribbed Turbulator

    Moallemi, Nima; Brinkerhoff, Joshua


    The generation of turbulent inflow conditions adds significant computational expense to direct numerical simulations (DNS) of turbulent pipe flows. Typical approaches involve introducing boxes of isotropic turbulence to the velocity field at the inlet of the pipe. In the present study, an alternative method is proposed that incurs a lower computational cost and allows the anisotropy observed in pipe turbulence to be physically captured. The method is based on a periodic DNS of a ribbed turbulator upstream of the inlet boundary of the pipe. The Reynolds number based on the bulk velocity and pipe diameter is 5300 and the blockage ratio (BR) is 0.06 based on the rib height and pipe diameter. The pitch ratio is defined as the ratio of rib streamwise spacing to rib height and is varied between 1.7 and 5.0. The generation of turbulent flow structures downstream of the ribbed turbulator are identified and discussed. Suitability of this method for accurate representation of turbulent inflow conditions is assessed through comparison of the turbulent mean properties, fluctuations, Reynolds stress profiles, and spectra with published pipe flow DNS studies. The DNS results achieve excellent agreement with the numerical and experimental data available in the literature.

  18. Piping Flexibility Analysis of the Primary Cooling System of TRIGA 2000 Bandung Reactor due to Earthquake

    H.P. Rahardjo


    Full Text Available Earthquakes in a nuclear installation can overload a piping system which is not flexible enough. These loads can be forces, moments and stresses working on the pipes or equipments. If the load is too large and exceed the allowable limits, the piping and equipment can be damaged and lead to overall system operation failure. The load received by piping systems can be reduced by making adequate piping flexibility, so all the loads can be transmitted homogenously throughout the pipe without load concentration at certain point. In this research the analysis of piping stress has been conducted to determine the size of loads that occured in the piping of primary cooling system of TRIGA 2000 Reactor, Bandung if an earthquake happened in the reactor site. The analysis was performed using Caesar II software-based finite element method. The ASME code B31.1 arranging the design of piping systems for power generating system (Power Piping Code was used as reference analysis method. Modeling of piping systems was based on the cooling piping that has already been installed and the existing data reported in Safety Analysis Reports (SARs of TRIGA 2000 reactor, Bandung. The quake considered in this analysis is the earthquake that occurred due to the Lembang fault, since it has the Peak Ground Acceleration (PGA in the Bandung TRIGA 2000 reactor site. The analysis results showed that in the static condition for sustain and expansion loads, the stress fraction in all piping lines does not exceed the allowable limit. However, during operation moment, in dynamic condition, the primary cooling system is less flexible at sustain load, ekspansi load, and combination load and the stress fraction have reached 95,5%. Therefore a pipeline modification (rerouting is needed to make pipe stress does not exceed the allowable stress. The pipeline modification was carried out by applied a gap of 3 mm in the X direction of the support at node 25 and eliminate the support at the node

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

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


    A 35-year-old mother was scheduled to be the living donor for liver transplantation to her second son,who suffered from biliary atresia complicated with biliary cirrhosis at the age of 2 years.The operative plan was to recover the left lateral segment of the mother's liver for living donor transplantation.With the use of cholangiography at the time of surgery,we found the right anterior segmental duct(RASD) emptying directly into the cystic duct,and the catheter passed into the RASD.After repairing the inci...

  20. Underground pipe inspection device and method

    Germata, Daniel Thomas [Wadsworth, IL


    A method and apparatus for inspecting the walls of an underground pipe from inside the pipe in which an inspection apparatus having a circular planar platform having a plurality of lever arms having one end pivotably attached to one side of the platform, having a pipe inspection device connected to an opposite end, and having a system for pivoting the lever arms is inserted into the underground pipe, with the inspection apparatus oriented with the planar platform disposed perpendicular to the pipe axis. The plurality of lever arms are pivoted toward the inside wall of the pipe, contacting the inside wall with each inspection device as the apparatus is conveyed along a length of the underground pipe.

  1. Study on dinamic behavior and least burying depth of underground protective pipe

    Kataoka, Tetsuyuki; Kokusyo, Goji; Tanaka, Yukihisa; Kobayashi, Seiichi


    Effect of unit load per travel wheel on the protective pipe was studied when electricity cable distribution lines were buried in the depth less than the present standard for electric equipment, and logical burying depth was investigated. Test items were material test of the protective pipe, indoor load test, and field test at loamy ground. Impact resistance hard PVC pipe was used as the protective pipe, and its strength and elastic modulus were measured. Along with these tests, it was confirmed that there was no problem of cracking by repeated flattening or breakage by fatigue. By indoor test, it was observed that, in case of shallow burying, creap deformation was small, stress concentrate occured at the middle of axial direction, and that flattening ratio was seriously affected by the method of backfilling. Field test was conducted by applying the static load of a 20 ton dump truck, and the deformation, stress, and subsidence of the protective pipe, were measured. As the conclusion of those experiments, it was found that burying of protective pipe in the depth of not less than 30 cm is allowable, as long as sufficient bakfilling is made. (14 figs, 3 tabs, 3 refs)

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

    McKeon, Brian D.


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

  3. Omphalomesenteric duct cyst with gastric mocosa: A case report


    Persistance of the omphalomesenteric duct may lead to several anomalies including umblical sinus, umblical cyst, MeckeVs diverticulum or patent omphalomesenteric duct fistula. Clinical manifestations of umblical disorders are usually nonspecific; use of cross-sectional imaging can help identify most of these entities because of their typical locations and distributions in continuity with the other organs and guide therapy. A case of omphalomesenteric duct cyst are presented and analysed toget...

  4. Finite element thermal analysis of the fusion welding of a P92 steel pipe

    A. H. Yaghi


    Full Text Available Fusion welding is common in steel pipeline construction in fossil-fuel power generation plants. Steel pipes in service carry steam at high temperature and pressure, undergoing creep during years of service; their integrity is critical for the safe operation of a plant. The high-grade martensitic P92 steel is suitable for plant pipes for its enhanced creep strength. P92 steel pipes are usually joined together with a similar weld metal. Martensitic pipes are sometimes joined to austenitic steel pipes using nickel based weld consumables. Welding involves severe thermal cycles, inducing residual stresses in the welded structure, which, without post weld heat treatment (PWHT, can be detrimental to the integrity of the pipes. Welding residual stresses can be numerically simulated by applying the finite element (FE method in Abaqus. The simulation consists of a thermal analysis, determining the temperature history of the FE model, followed by a sequentially-coupled structural analysis, predicting residual stresses from the temperature history.

    In this paper, the FE thermal analysis of the arc welding of a typical P92 pipe is presented. The two parts of the P92 steel pipe are joined together using a dissimilar material, made of Inconel weld consumables, producing a multi-pass butt weld from 36 circumferential weld beads. Following the generation of the FE model, the FE mesh is controlled using Model Change in Abaqus to activate the weld elements for each bead at a time corresponding to weld deposition. The thermal analysis is simulated by applying a distributed heat flux to the model, the accuracy of which is judged by considering the fusion zones in both the parent pipe as well as the deposited weld metal. For realistic fusion zones, the heat flux must be prescribed in the deposited weld pass and also the adjacent pipe elements. The FE thermal results are validated by comparing experimental temperatures measured by five thermocouples on the

  5. An overview of environmental degradation of materials in nuclear power plant piping systems

    Shack, W.J.


    Piping in light water reactor (LWR) power systems is affected by several types of environmental degradation: intergranular stress corrosion cracking (IGSCC) of austenitic stainless steel piping in boiling water reactors (BWRs) has required research, inspection, and mitigation programs that will ultimately cost several billion dollars; erosion-corrosion of carbon steel piping has been observed frequently in the secondary systems of both BWRs and pressurized water reactors (PWRs); the effect of the BWR environment can greatly diminish the design margin inherent in the ASME Section III fatigue design curves for carbon steel piping; and cast stainless steels are subject to embrittlement after extended thermal aging at reactor operating temperatures. These problems are being addressed by wide-ranging research programs in this country and abroad. The purpose of this review is to highlight some of the accomplishments of these programs and to note some of the remaining unanswered questions.

  6. Numerical Investigation on Mixed Convection in Triangular Cross-Section Ducts with Nanofluids

    Oronzio Manca


    Full Text Available Convective heat transfer can be enhanced passively by changing flow geometry and boundary conditions or by improving the thermal conductivity of the working fluid, for example, introducing suspended small solid nanoparticles. In this paper, a numerical investigation on laminar mixed convection in a water-Al2O3-based nanofluid, flowing in a triangular cross-sectioned duct, is presented. The duct walls are assumed at uniform temperature, and the single-phase model has been employed in order to analyze the nanofluid behaviour. The hydraulic diameter is equal to 0.01 m. A fluid flow with different values of Richardson number and nanoparticle volume fractions has been considered. Results show the increase of average convective heat transfer coefficient and Nusselt number for increasing values of Richardson number and particle concentration. However, also wall shear stress and required pumping power profiles grow significantly.

  7. Method for Observing Intravascular BongHan Duct

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


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

  8. Biliary stenting for management of common bile duct stones.

    Choudhuri, G; Sharma, B C; Saraswat, V A; Agarwal, D K; Baijal, S S


    Large and multiple common bile duct stones may defy extraction despite an adequate endoscopic papillotomy. We treated 65 patients with symptomatic bile duct stones with endoscopic stents after failed attempts at stone extraction. Of the 65 patients, bile duct stones were extracted in eight at a second attempt, 29 underwent elective surgery and 28 patients were followed with the stent in situ for 21-52 months (median 42 months). During follow up, two patients had recurrent pain and two required surgery. The remaining 24 patients remained asymptomatic. Biliary stenting is a safe and effective mode of treatment for common bile duct stones in patients who have failed stone extraction after endoscopic papillotomy.

  9. Flexible metallic seal for transition duct in turbine system

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


    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.

  10. Experimental investigation of a rapidly rotating turbulent duct flow

    Maartensson, G.E.; Johansson, A.V. [Department of Mechanics, KTH, 10044 Stockholm (Sweden); Gunnarsson, J. [Bombardier Transportation, Vaesteraas (Sweden); Moberg, H. [Alfa Laval, 14780 Tumba (Sweden)


    Rapidly rotating duct flow is studied experimentally with Rotation numbers in the interval. To achieve this, in combination with relatively high Reynolds numbers (5,000-30,000 based on the hydraulic radius), water was used as the working medium. Square and rectangular duct cross-sections were used and the angle between the rotation vector and the main axis of the duct was varied. The influence of the rotation on the pressure drop in the duct was investigated and suitable scalings of this quantity were studied. (orig.)

  11. Leaf seal for transition duct in turbine system

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


    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.


    O. E. Iryshkin


    Full Text Available Aim. To study the clinica-morphological features of syndromatic and nonsyndromatic paucity of intrahepatic bile ducts in pediatric liver transplant recipients. Methods and results. The clinical records were analyzed and histological studies of native livers of 20 children, who had suffered from paucity of intrahepatic bile ducts and to whom liver transplantation were made, were completed. The obtained data indicate higher levels of AST in patients with nonsyndromatic paucity of intrahepaticbile ducts (p = 0,023. Ductopenia was the more frequent indication of syndromatic form of paucity of intrahepatic bile ducts (p = 0,01, while ductular proliferations, which form «ductular structure», were discovered more often in nonsyndromatic paucity of intrahepaticbile ducts (p = 0,03. The extent of inflammatory-destructive changes was more expressed in nonsyndromatic pauci- ty of intrahepatic bile ducts (p = 0,01. Fibrosis or cirrhosis was formed more often in nonsyndromatic paucity of intrahepatic bile ducts (p = 0,008. Conclusion. Our results indicate more severe clinical and morphological manifestations in nonsyndromatic paucity of intrahepatic bile ducts. These findings may suggest about heavier liver condition in patient with nonsyndromatic form of paucity of intrahepatic bile ducts

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


    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)

  14. Convolution seal for transition duct in turbine system

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


    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.

  15. Development of high strength line pipe for Arctic applications

    Collins, L.E.; Klein, R.; Bai, D. [Evraz Inc., Regina, SK (Canada). Frontier Pipe Research Unit


    The pipelines that will carry large volumes of natural gas from the Mackenzie Delta and the Alaska North Slope to Alberta will have to meet stringent new requirements on material performance. High strength steels with thick pipe walls will be needed to accommodate the high operating pressure that will be needed to transmit gas over long distances. In addition, low operating temperatures and strain-based designs will be needed to meet Arctic operating conditions in areas of continuous or discontinuous permafrost. The Mackenzie Gas Project (MGP) has specified 762 mm OD x 16.2 mm WT Grade 550 (APIx80). Although the pipe has a high degree of ductility, material performance is of concern in terms of girth welds and associated heat affected zones. Studies have shown that the weld strength must overmatch the longitudinal strength of the pipe by at least 5 per cent in order to deflect any failure from a crack on the weld fusion line. The weld itself and the HAZ must also demonstrate a high degree of toughness. While proponents of the Alaska gas pipeline wish to use Grade 690 (APIx100) line pipe, full stress capacity tests have yet to be completed for Grade 690 material in the preferred gauge of 19 to 25 mm. Therefore, this paper examined 3 key issues pertaining to the performance of high strength line pipe in strain-based designs. These included girth weld HAZ toughness; work hardening characteristics; and achievement of very high strength levels. It was concluded that much more effort is needed to fully optimize these steels and to translate preliminary laboratory solutions to workable processing technologies. 15 refs., 2 tabs., 8 figs.

  16. Curvature effects on the velocity profile in turbulent pipe flow.

    Grossmann, Siegfried; Lohse, Detlef


    Prandtl and von Kármán have developed the famous log-law for the mean velocity profile for turbulent flow over a plate. The log-law has also been applied to turbulent pipe flow, though the wall surface is curved (in span-wise direction) and has finite diameter. Here we discuss the theoretical framework, based on the Navier-Stokes equations, with which one can describe curvature effects and also the well-known finite-size effects in the turbulent mean-velocity profile. When comparing with experimental data we confirm that the turbulent eddy viscosity must contain both curvature and finite-size contributions and that the usual ansatz for the turbulent eddy viscosity as being linear in the wall distance is insufficient, both for small and large wall distances. We analyze the experimental velocity profile in terms of an r-dependent generalized turbulent viscosity [Formula: see text] (with [Formula: see text] being the wall distance, a pipe radius, u * shear stress velocity, and g([Formula: see text]/a) the nondimensionalized viscosity), which reflects the radially strongly varying radial eddy transport of the axial velocity. After the near wall linear viscous sublayer, which soon sees the pipe wall's curvature, a strong transport (eddy) activity steepens the profile considerably, leading to a maximum in g([Formula: see text]/a) at about half radius, then decreasing again towards the pipe center. This reflects the smaller eddy transport effect near the pipe's center, where even in strongly turbulent flow (the so-called "ultimate state") the profile remains parabolic. The turbulent viscous transport is strongest were the deviations of the profile from parabolic are strongest, and this happens in the range around half radius.

  17. Neutron residual stress measurements in linepipe

    Law, Michael [ANTSO, PMB1 Menai, NSW, 2234 (Australia)]. E-mail:; Gnaepel-Herold, Thomas [Department of Materials Science and Engineering, NCNR and University of Maryland (United States); Luzin, Vladimir [Department of Materials Science and Engineering, NCNR and University of Maryland (United States); Bowie, Graham [cNCNR and State University of New York at Stoneybrook (United States): Blue Scope Steel (Australia)


    Residual stresses in gas pipelines are generated by manufacturing and construction processes and may affect the subsequent pipe integrity. In the present work, the residual stresses in eight samples of linepipe were measured by neutron diffraction. Residual stresses changed with some coating processes. This has special implications in understanding and mitigating stress corrosion cracking, a major safety and economic problem in some gas pipelines.

  18. Seminar on countermeasures for pipe cracking in BWRs. Volume 2 of 4



    Intergranular stress corrosion cracking of welded type 304 stainless steel in the recirculation piping of boiling water reactors has had an impact on plant availability and reliability since the fall of 1974. Investigtions of this problem have resulted in significant progress in understanding the phenomenon and providing an engineering resolution by developing and qualifying countermeasures. A number of these countermeasures including solution heat treatment, corrosion resistant clad, alternate pipe materials, induction heating stress improvement and heat sink welding have been implemented. Separate abstracts are included for each of the papers presented.

  19. Seminar on countermeasures for pipe cracking in BWRs. Volume 3 of 4



    Intergranular stress corrosion cracking of welded type 304 stainless steel in the recirculation piping of boiling water reactors has had an impact on plant availability and reliability since the fall of 1974. Investigations of this problem have resulted in significant progress in understanding the phenomenon and providing an engineering resolution by developing and qualifying countermeasures. A number of these countermeasures including solution heat treatment, corrosion resistant clad, alternate pipe materials, induction heating stress improvement and heat sink welding have been implemented. Separate abstracts are included for each of the papers presented.

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

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


    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.

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

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


    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.

  2. Radiation of sound from unflanged cylindrical ducts

    Hartharan, S. L.; Bayliss, A.


    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.

  3. Classification and management of bile duct injuries


    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...

  4. Inspection of Fusion Joints in Plastic Pipe

    Connie Reichert


    The standard method of joining plastic pipe in the field is the butt fusion process. As in any pipeline application, joint quality greatly affects overall operational safety of the system. Currently no simple, reliable, cost-effective method exists for assessing the quality of fusion joints in the field. Visual examination and pressure testing are current nondestructive approaches, which do not provide any assurance about the long-term pipeline performance. This project developed, demonstrated, and validated an in-situ nondestructive inspection method for butt fusion joints in gas distribution plastic pipelines. The inspection system includes a laser-based image-recognition system that automatically generates and interprets digital images of pipe joints and assigns them a pass/fail rating, which eliminates operator bias in evaluating joint quality. An EWI-patented process, the Weld Zone Inspection Method (WZIM) was developed in which local heat is applied to the joint region to relax the residual stresses formed by the original joining operation, which reveals the surface condition of the joint. In cases where the joint is not formed under optimal conditions, and the intermolecular forces between contacting surfaces are not strong enough, the relaxation of macromolecules in the surface layer causes the material to pull back, revealing a fusion line. If the joint is sound, the bond line image does not develop. To establish initial feasibility of the approach, welds were performed under standard and nonstandard conditions. These welds were subjected to the WZIM and two destructive forms of testing: short-term tensile testing and long-term creep rupture testing. There appears to be a direct correlation between the WZIM and the destructive testing results. Although WZIM appears to be more sensitive than destructive testing can verify, the approach appears valid.

  5. Numerical simulation of pulsatile flow in rough pipes

    Chin, Cheng; Monty, Jason; Ooi, Andrew; Illingworth, Simon; Marusic, Ivan; Skvortsov, Alex


    Direct numerical simulation (DNS) of pulsatile turbulent pipe flow is carried out over three-dimensional sinusoidal surfaces mimicking surface roughness. The simulations are performed at a mean Reynolds number of Reτ 540 (based on friction velocity, uτ, and pipe radii, δ) and at various roughness profiles following the study of Chan et al., where the size of the roughness (roughness semi-amplitude height h+ and wavelength λ+) is increased geometrically while maintaining the height-to-wavelength ratio of the sinusoidal roughness element. Results from the pulsatile simulations are compared with non-pulsatile simulations to investigate the effects of pulsation on the Hama roughness function, ΔU+ . Other turbulence statistics including mean turbulence intensities, Reynolds stresses and energy spectra are analysed. In addition, instantaneous phase (eg. at maximum and minimum flow velocities) and phase-averaged flow structures are presented and discussed.

  6. Incrustations detection system for petroleum transport pipes based on gamma transmission; Sistema de deteccao de incrustacoes em dutos de transporte de petroleo pela tecnica de transmissao gama

    Soares, Milton


    The scale formed over the inner walls of the ducts conveying the extracted product from offshore oil wheels is a major cause of losses to companies and in some cases even the safety is affected. The consequence of such fouling is the duct's square section reduction that causes extraction flow decrease and can also cause an increase in pressure inside the wheel, with serious consequences for safety. The objective of this work is to propose a mobile inspection system, which can be transported by underwater robots to inspect the lines of ducts in the outputs of the oil wheels. The measurement method to be adopted will be the gamma rays' beam attenuation at a predetermined position of the pipe. This transmission value compared to a clear pipe reading will show if the thickness of the inlay is larger or smaller than an assumed thickness. To carry out the measurements it was designed and built an electronic system comprising power supply, amplifier, single channel analyzer and a counter timer that was connected to a CsI scintillator detector coupled to a PIN photodiode. The system was set up to perform measurements with constant accuracy of ±1%. Tests during the study demonstrated the effectiveness of the proposed method with the obtained results with a carbon steel duct section of 270 mm diameter, removed from the field, with asymmetric BaSO4 inlay. (author)

  7. K{sub I}-T estimation for embedded flaws in pipes - Part II: Circumferentially oriented cracks

    Qian Xudong, E-mail: [Department of Civil Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576 (Singapore)


    This paper, in parallel to the investigation on axially embedded cracks reported in the companion paper, presents a numerical study on the linear-elastic K{sub I} and T-stress values over the front of elliptical cracks circumferentially embedded in the wall of a pipe/cylindrical structure, under a uniform pressure applied on the inner surface of the pipe. The numerical procedure employs the interaction-integral approach to compute the linear-elastic stress-intensity factor (SIF) K{sub I} and T-stress values for embedded cracks with practical sizes at different locations in the wall of the pipe. The parametric study covers a wide range of geometric parameters for embedded cracks in the pipe, including: the wall thickness to the inner radius ratio (t/R{sub i}), the crack depth over the wall thickness ratio (a/t), the crack aspect ratio (a/c) and the ratio of the distance from the centerline of the crack to the outer surface of the pipe over the pipe wall thickness (e{sub M}/t). The parametric investigation identifies a significant effect of the remaining ligament length on both the T-stress and K{sub I} values at the crack-front location (denoted by point O) nearest to the outer surface of the pipe and at the crack-front location (denoted by point I) nearest to the inner surface of the pipe. The numerical investigation establishes the database to derive approximate functions from a nonlinear curve-fitting procedure to predict the T-stress and K{sub I} values at three critical front locations of the circumferentially embedded crack in a pipe: points O, I and M. The proposed T-stress and K{sub I} functions utilize a combined second-order polynomial and a power-law expression, which presents a close agreement with the T-stress and K{sub I} values computed from the very detailed finite element models. The comparison between the circumferentially embedded crack and the axially embedded crack indicates that both the T-stress and K{sub I} values at crack-front points O and

  8. Computation on pipe dynamic response induced by deflagration of H2 and air mixture


    Computation is devoted to evaluating structural safety of a heat exchanger inside a reactor whose geometry can be simplified as outer and inner pipes as well as a chamber. This paper has numerically studied deflagration of hydrogen air mixture and pipe dynamic responses. The Navier-Stokes equations coupled with multi-species mass equation are solved by TVD scheme to get flow-field solution based on MPI and multi-block methods. Combustion is described by a 11-species and 23-step reaction model. The source term is treated implicitly to involve species production and depletion. Ignition is approximated by input energy CpT per unit mass in a specified period and zone. Finally,contours of pressure and OH mass fraction at different time pe-riods and pressure histories at fixed points are obtained. When loading is specified as wall pressure,virtual work theorem in Lagrangian frame which describes pipe response is solved by FEM to obtain stress and strain distributions. Results show that shock waves can be generated and reflected on the walls of the chamber and pipes. The shock waves and flame can not be dis-sipated in a narrow gap spanning 2 mm. Meanwhile,stress waves are generated. They propagate outwards on the inner and outer pipe walls. At the gap exit,shock wave diffracts and impacts on the inner pipe walls. Coupled with hot jet from the gap,reignition occurs on the inner pipe wall surfaces. Then,flame catches up the leading shock and shock front deforms into a planar one although the shock front passes through a short divergent section downstream. Also,stress concentrates along the intersected lines among the top,bottom and side walls. This means that the chamber is an easily damaged component. The methods provided in this paper can be used to evaluate structural safety.

  9. Numerical investigation of turbulent fluid flow and heat transfer in complex ducts

    Rokni, M.


    The need for a reliable and reasonable accurate turbulence model without specific convergence problem for calculating duct flows in industrial applications has become more evident. In this study a general computational method has been developed for calculating turbulent quantities in any arbitrary three dimensional duct. Four different turbulence models for predicting the turbulent Reynolds stresses namely; standard k-{epsilon} model, the non-linear-k-{epsilon} model of Speziale, an Explicit Algebraic Stress Model (EASM) and a full Reynolds Stress Model (RSM) are compared with each other. The advantages, disadvantages and accuracy of these models are discussed. The turbulent heat fluxes are modeled by the SED concept, the GGDH and the WET methods. The advantages of GGDH and WET compared to SED are discussed and the limitations of these models are clarified. The two-equation model of temperature invariance and its dissipation rate for calculating turbulent heat fluxes are also discussed. The low Reynolds number version of all the models are considered except for the RSM. At high Reynolds numbers the wall functions for both the temperature field and the flow field are applied. It has been shown that the standard k-{epsilon} model with the curvilinear transformation provides false secondary motions in general non-orthogonal ducts and can not be used for predicting the turbulent secondary motions in ducts. The numerical method is based on the finite volume technique with non-staggered grid arrangement. The SIMPLEC algorithm is used for pressure-velocity coupling. A modified SIP and TDMA solving methods are implemented for solving the equations. The van Leer, QUICK and hybrid schemes are applied for treating the convective terms. However, in order to achieve stability in the k and {epsilon} equations, the hybrid scheme is used for the convective terms in these equations. Periodic boundary conditions are imposed in the main flow direction for decreasing the number of

  10. 46 CFR 154.310 - Cargo piping systems.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo piping systems. 154.310 Section 154.310 Shipping... Arrangements § 154.310 Cargo piping systems. Cargo liquid or vapor piping must: (a) Be separated from other piping systems, except where an interconnection to inert gas or purge piping is required by §...

  11. 46 CFR 154.500 - Cargo and process piping standards.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo and process piping standards. 154.500 Section 154... Equipment Cargo and Process Piping Systems § 154.500 Cargo and process piping standards. The cargo liquid and vapor piping and process piping systems must meet the requirements in §§ 154.503 through...

  12. 46 CFR 154.522 - Materials for piping.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Materials for piping. 154.522 Section 154.522 Shipping... Process Piping Systems § 154.522 Materials for piping. (a) The materials for piping systems must meet § 154.625 for the minimum design temperature of the piping, except the material for open ended...

  13. 46 CFR 119.730 - Nonferrous metallic piping materials.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Nonferrous metallic piping materials. 119.730 Section... INSTALLATION Piping Systems § 119.730 Nonferrous metallic piping materials. (a) Nonferrous metallic piping materials are acceptable for use in the following: (1) Non-vital systems; (2) Aluminum fuel piping on...

  14. Chloride and potassium conductances of cultured human sweat ducts

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


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

  15. Bidirectional infrasonic ducts associated with sudden stratospheric warming events

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


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

  16. Diverticular bile duct lesion in chronic active hepatitis

    Vyberg, M


    Liver needle biopsies from patients with non-A, non-B chronic active hepatitis and so-called abnormal bile duct epithelium were studied with a three-dimensional method. Photographs of bile duct structures in serial sections were transferred to acrylic plates. Five bile duct lesions of a not previ......Liver needle biopsies from patients with non-A, non-B chronic active hepatitis and so-called abnormal bile duct epithelium were studied with a three-dimensional method. Photographs of bile duct structures in serial sections were transferred to acrylic plates. Five bile duct lesions...... cells, but most were larger, with rounded nuclei, prominent nucleoli and abundant eosinophilic cytoplasm, sometimes with periodic acid-Schiff-positive, diastase-resistant granules. The lesions were only partly surrounded by a basement membrane. They were all embedded in a tight mononuclear inflammatory...... infiltrate associated with pronounced periportal piecemeal necrosis. In two cases, a germinal center was adjacent to the epithelium. The pathogenesis of the diverticular bile duct lesion is unknown, but the diverticuli probably represent Hering ducts and groups of periportal liver cells which have escaped...

  17. Cystic duct closure by sealing with bipolar electrocoagulation

    Schulze, S; Damgaard, B; Jørgensen, Lars Nannestad;


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

  18. Intracellular pH in rat pancreatic ducts

    Novak, I; Hug, M; Greger, R


    In order to study the mechanism of H+ and HCO3- transport in a HCO3- secreting epithelium, pancreatic ducts, we have measured the intracellular pH (pHi) in this tissue using the pH sensitive probe BCECF. We found that exposures of ducts to solutions containing acetate/acetic acid or NH4+/NH3 buff...

  19. Radiopaque intrahepatic duct stones in plain radiograph: case report

    Kim, Mi Young; Suh, Chang Hae; Park, Chan Sup; Chung, Won Kyun [College of Medicine, Inha University, Seongnam (Korea, Republic of)


    We experienced 3 cases of intrahepatic duct stones detected on plain radiographs. The patients had history of multiple episodes of recurrent cholangitis. Radiographic characteristics of these stones included multiple, round or rectangular radiopaque densities surrounded by calcified rim; these densities showed a branching pattern along the intrahepatic ducts.

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

    Nayfeh, A. H.


    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.

  1. Sound Radiation Characteristics of a Rectangular Duct with Flexible Walls

    Praveena Raviprolu


    Full Text Available Acoustic breakout noise is predominant in flexible rectangular ducts. The study of the sound radiated from the thin flexible rectangular duct walls helps in understanding breakout noise. The current paper describes an analytical model, to predict the sound radiation characteristics like total radiated sound power level, modal radiation efficiency, and directivity of the radiated sound from the duct walls. The analytical model is developed based on an equivalent plate model of the rectangular duct. This model has considered the coupled and uncoupled behaviour of both acoustic and structural subsystems. The proposed analytical model results are validated using finite element method (FEM and boundary element method (BEM. Duct acoustic and structural modes are analysed to understand the sound radiation behaviour of a duct and its equivalence with monopole and dipole sources. The most efficient radiating modes are identified by vibration displacement of the duct walls and for these the radiation efficiencies have been calculated. The calculated modal radiation efficiencies of a duct compared to a simple rectangular plate indicate similar radiation characteristics.

  2. Piping inspection carriage having axially displaceable sensor

    Zollinger, William T.; Treanor, Richard C.


    A pipe inspection instrument carriage for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

  3. Wave Propagation in Pipe-like Structures

    Morsbøl, Jonas

    Pipe-like shell structures are found in a wide range of practical applications such as: Wind turbine towers, jet engines, brass instruments, and piping systems. For many of these applications, structural vibrations play an important role for their performance. This thesis will in particular focus...... on how the curvature on a thin-walled pipe, as well as a changing radius along a straight thin-walled pipe, affects the waveguide properties. It shows that the waveguide properties of curved pipes roughly can be divided into three regimes: The curved beam regime, the cylinder regime, and the torus regime....... In the curved beam regime the waveguide properties of the pipe can be approximated by classical curved beam theory while in the cylinder regime they can be approximated by cylindrical shell theory. In the torus regime none of the two other regimes apply, and a full-blown shell model is needed. For the straight...

  4. Lightweight Heat Pipes Made from Magnesium

    Rosenfeld, John N.; Zarembo, Sergei N.; Eastman, G. Yale


    Magnesium has shown promise as a lighter-weight alternative to the aluminum alloys now used to make the main structural components of axially grooved heat pipes that contain ammonia as the working fluid. Magnesium heat-pipe structures can be fabricated by conventional processes that include extrusion, machining, welding, and bending. The thermal performances of magnesium heat pipes are the same as those of equal-sized aluminum heat pipes. However, by virtue of the lower mass density of magnesium, the magnesium heat pipes weigh 35 percent less. Conceived for use aboard spacecraft, magnesium heat pipes could also be attractive as heat-transfer devices in terrestrial applications in which minimization of weight is sought: examples include radio-communication equipment and laptop computers.

  5. Intermediate Temperature Fluids for Heat Pipes and Loop Heat Pipes Project

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will develop heat pipe and loop heat pipe (LHP) working fluids for what is known as the intermediate...

  6. Effect of pressurization on helical guided wave energy velocity in fluid-filled pipes.

    Dubuc, Brennan; Ebrahimkhanlou, Arvin; Salamone, Salvatore


    The effect of pressurization stresses on helical guided waves in a thin-walled fluid-filled pipe is studied by modeling leaky Lamb waves in a stressed plate bordered by fluid. Fluid pressurization produces hoop and longitudinal stresses in a thin-walled pipe, which corresponds to biaxial in-plane stress in a plate waveguide model. The effect of stress on guided wave propagation is accounted for through nonlinear elasticity and finite deformation theory. Emphasis is placed on the stress dependence of the energy velocity of the guided wave modes. For this purpose, an expression for the energy velocity of leaky Lamb waves in a stressed plate is derived. Theoretical results are presented for the mode, frequency, and directional dependent variations in energy velocity with respect to stress. An experimental setup is designed for measuring variations in helical wave energy velocity in a thin-walled water-filled steel pipe at different levels of pressure. Good agreement is achieved between the experimental variations in energy velocity for the helical guided waves and the theoretical leaky Lamb wave solutions.

  7. Duct thermal performance models for large commercial buildings

    Wray, Craig P.


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

  8. Pipes under internal pressure and bending

    Catinaccio, A


    This article covers the general behaviour of a straight uniform pipe, with built-in open ends, subject to internal pressure and in plane bending or curvature. It is intended as a summary of the basic equations driving the unintuitive phenomena of bending and instability of pipes under internal pressure. The analysis covers in addition the investigation of opposite pressure stabilisation effects that can be observed in some orthotropic material pipes like composite pressure hoses.

  9. Crack shape developments and leak rates for circumferential complex-cracked pipes

    Brickstad, B.; Bergman, M. [SAQ Inspection Ltd., Stockholm (Sweden)


    A computerized procedure has been developed that predicts the growth of an initial circumferential surface crack through a pipe and further on to failure. The crack growth mechanism can either be fatigue or stress corrosion. Consideration is taken to complex crack shapes and for the through-wall cracks, crack opening areas and leak rates are also calculated. The procedure is based on a large number of three-dimensional finite element calculations of cracked pipes. The results from these calculations are stored in a database from which the PC-program, denoted LBBPIPE, reads all necessary information. In this paper, a sensitivity analysis is presented for cracked pipes subjected to both stress corrosion and vibration fatigue.

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

    Poinsatte, Philip; Thurman, Douglas; Hippensteele, Steven


    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.

  11. Hepatobiliary Scan in Infantile Spontaneous Perforation of Common Bile Duct

    Zeon, Seok Kil; Ryu, Jong Gul; Lee, Eun Young [Keimyung University School of Medicine, Taegu (Korea, Republic of); Lee, Jong Gil [Taegu Fatima Hospital, Taegu (Korea, Republic of)


    Spontaneous perforation of CBD in infant is a rare but fatal disease. We report a case of bile leakage from common bile duct in 11 months old girl with progressive abdominal distension and vomiting, preoperatively diagnosed by hepatobiliary scan with Tc-99m-DISIDA, which was confirmed by surgery. Operative cholangiogram showed a small perforation at the confluence of cystic duct and common bile duct with mild fusiform dilatation, and no definite abnormality in confluence of the common bile duct and pancreatic duct. Simple drainage of the free peritoneal bilous fluid and T-tube drainage were performed without any evidence of the complication. Patient was inevitable for 6 months OPD follow-up examination.

  12. Extravasation Mucocele Arising from a Lingual Thyroglossal Duct Remnant

    Mitsuhiko Nakahira


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

  13. Main-duct intraductal papillary mucinous adenoma of the pancreas

    Takuma Kensuke


    Full Text Available Abstract Background The prevalence of carcinoma in main-duct intraductal papillary mucinous neoplasm (IPMN is high, and surgical resection is recommended for all patients with a main-duct IPMN. Results A main-duct IPMN with typical imagings including protruding lesions in the dilated main pancreatic duct was resected, but the histology was intraductal papillary mucinous adenoma of the pancreas. Discussion It has been reported that the presence of mural nodules and dilatation of MPD are significantly higher in malignant IPMNs. The presented case had protruding lesions in the dilated main pancreatic duct on endoscopic ultrasonography, but the histology was adenoma. Conclusion Preoperative distinction between benign and malignant IPMNs is difficult.

  14. Cystic duct remnant mucocele in a liver transplant recipient

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


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

  15. Effect of Glass Reinforced Epoxy (GRE) pipe filled with Geopolymer Materials for Piping Application: Compression Properties


    The aim of this paper is to achieve the highest compressive strength of glass reinforced epoxy pipe with the geopolymer filler content of weight percentage that were used in glass reinforced epoxy pipe. The samples were prepared by using the filament winding method. The effect of weight percentage of geopolymer materials in epoxy hardener was studied under mechanical testing, which is using the compression test. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled wi...

  16. Drop Weight Impact Behavior of Al-Si-Cu Alloy Foam-Filled Thin-Walled Steel Pipe Fabricated by Friction Stir Back Extrusion

    Hangai, Yoshihiko; Nakano, Yukiko; Utsunomiya, Takao; Kuwazuru, Osamu; Yoshikawa, Nobuhiro


    In this study, Al-Si-Cu alloy ADC12 foam-filled thin-walled stainless steel pipes, which exhibit metal bonding between the ADC12 foam and steel pipe, were fabricated by friction stir back extrusion. Drop weight impact tests were conducted to investigate the deformation behavior and mechanical properties of the foam-filled pipes during dynamic compression tests, which were compared with the results of static compression tests. From x-ray computed tomography observation, it was confirmed that the fabricated foam-filled pipes had almost uniform porosity and pore size distributions. It was found that no scattering of the fragments of collapsed ADC12 foam occurred for the foam-filled pipes owing to the existence of the pipe surrounding the ADC12 foam. Preventing the scattering of the ADC12 foam decreases the drop in stress during dynamic compression tests and therefore improves the energy absorption properties of the foam.

  17. Theoretical and experimental analysis of dynamic processes of pipe branch for supply water to the Pelton turbine

    Jovanović Miomir Lj.


    Full Text Available The paper presents the results of the analysis of pipe branch A6 to feed the Hydropower Plant ”Perućica” with integrated action Pelton turbines. The analysis was conducted experimentally (tensometric and numerically. The basis of the experimental research is the numerical finite element analysis of pipe branch A6 in pipeline C3. Pipe branch research was conducted in order to set the experiment and to determine extreme stress states. The analysis was used to perform the determination of the stress state of a geometrically complex assembly. This was done in detail as it had never been done before, even in the design phase. The actual states of the body pipe branch were established, along with the possible occurrence of water hammer accompanied by the appearance of hydraulic oscillation. This provides better energetic efficiency of the turbine devices. [Projekat Ministarstva nauke Republike Srbije, br. TR35049 and br. TR 33040

  18. Development of bore tools for pipe inspection

    Oka, Kiyoshi; Nakahira, Masataka; Taguchi, Kou; Ito, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    In the International Thermonuclear Reactor (ITER), replacement and maintenance on in-vessel components requires that all cooling pipes connected be cut and removed, that a new component be installed, and that all cooling pipes be rewelded. After welding is completed, welded area must be inspected for soundness. These tasks require a new work concept for securing shielded area and access from narrow ports. Tools had to be developed for nondestructive inspection and leak testing to evaluate pipe welding soundness by accessing areas from inside pipes using autonomous locomotion welding and cutting tools. A system was proposed for nondestructive inspection of branch pipes and the main pipe after passing through pipe curves, the same as for welding and cutting tool development. Nondestructive inspection and leak testing sensors were developed and the basic parameters were obtained. In addition, the inspection systems which can move inside pipes and conduct the nondestructive inspection and the leak testing were developed. In this paper, an introduction will be given to the current situation concerning the development of nondestructive inspection and leak testing machines for the branch pipes. (author)

  19. Water pipe smoking and dermatologic consequences.

    Wollina, U


    Water pipe smoking is a recently growing addiction worldwide. It has become popular in Africa and the Western World and enfaces a renaissance in Middle East and Asia. The smoking technique leads to a different exposure to potential hazardous compounds compared to cigarette or classical pipe smoking. The common assumption that water pipe smoking is less dangerous to health is not substantiated by scientific data. Non-tobacco-based preparations reduce the exposure to nicotine but may contain equal or even higher concentrations of other toxic compounds. The medical literature on adverse effect of water pipe smoking on skin and oral mucosa is reviewed but future research is a demand.

  20. Bile duct emptying in response to fat: a validation study.

    Hunt, D R; Scott, A J


    Fatty meal sonography has been suggested to assess patients with biliary pain after cholecystectomy, but the effects of gallbladder removal on biliary dynamics has not been studied prospectively. Before elective cholecystectomy, 25 patients had their common hepatic ducts' diameter measured by ultrasonography before and after a fat stimulus. In 23, tests were repeated 1 month, 1 year, and 5 years after surgery. In preoperative studies, 5 patients showed dilatation after fat and 2 of these had stones in the common bile duct. However, another 4 patients with stones or sludge in the duct did not show dilatation, so that the response to fat was a poor indicator of patients requiring common bile duct exploration. No patient had major symptoms after surgery. At 1 month and 12 months, the response to fat was variable with more than half of those tested showing no decrease in duct size. A more consistent pattern emerged at 5 years, when 14 of 18 patients tested showed a decrease in common hepatic duct after fat; 3 were unchanged and 1 increased by 1 mm. The response to fat was less consistent and more difficult to measure in the common bile duct, even 5 years after operation. It was concluded that not all patients with indications for exploration of the common bile duct on operative cholangiography show a dilatation response to fat on preoperative testing. Also, fatty meal sonography should be used with caution because the response to fat in asymptomatic patients soon after operation is unpredictable, with occasional patients showing dilation without apparent obstruction. Measurement of common hepatic duct is preferred to common bile duct and increases in diameter of 1 mm are probably not significant.

  1. Lacrimal Duct Occlusion Is Associated with Infectious Keratitis

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


    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

  2. Location of Agricultural Drainage Pipes and Assessment of Agricultural Drainage Pipe Conditions Using Ground Penetrating Radar

    Methods are needed to not only locate buried agricultural drainage pipe, but to also determine if the pipes are functioning properly with respect to water delivery. The primary focus of this research project was to confirm the ability of ground penetrating radar (GPR) to locate buried drainage pipe ...

  3. Antioxidant Effect of Sepia Ink Extract on Extrahepatic Cholestasis Induced by Bile Duct Ligation in Rats

    Hanan Saleh; Amel M Soliman; Ayman S Mohamed; Mohamed-Assem S Marie


    Objective The aim of our study was to assess the complications of hepatic fibrosis associated with bile duct ligation and the potential curative role of sepia ink extract in hepatic damage induced by bile duct ligation. Methods Rattus norvegicus rats were divided into 3 groups: Sham-operated group, model rats that underwent common bile duct ligation (BDL), and BDL rats treated orally with sepia ink extract (200 mg/kg body weight) for 7, 14, and 28 d after BDL. Results There was a significant reduction in hepatic enzymes, ALP, GGT, bilirubin levels, and oxidative stress in the BDL group after treatment with sepia ink extract. Collagen deposition reduced after sepia ink extract treatment as compared to BDL groups, suggesting that the liver was repaired. Histopathological examination of liver treated with sepia ink extract showed moderate degeneration in the hepatic architecture and mild degeneration in hepatocytes as compared to BDL groups. Conclusion Sepia ink extract provides a curative effect and an antioxidant capacity on BDL rats and could ameliorate the complications of liver cholestasis.

  4. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    Amir M. Alani


    Full Text Available In this paper, a stochastic finite element method (SFEM is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  5. Experimental determination of tunnel ventilation axial ducted fan performance

    Šekularac Milan B.


    Full Text Available To investigate traffic tunnel ventilation flows, a scaled model of a traffic tunnel with longitudinal ventilation system based on ducted fans is used. Flows in tunnels are influenced by tunnel geometry, fan characteristics, ventilation operation scenario, vehicle traffic, atmospheric factors, etc. To analyze flow fields of tunnels in detail, knowledge of tunnel jet-fan properties and turbulent flow characteristics at the fan exit are required, and can be used as input data for CFD boundary conditions of tunnel flow computation. For this purpose experimental measurements were done using the hot wire anemometry technique. The obtained results, trough ensemble-averaged and time averaged profiles of all velocity components, turbulence intensity, turbulent kinetic energy, integral flow length scales, available Reynolds stresses, Turbulent kinetic energy production rates and the fan thrust performance, are presented. These data allow us to analyze in more detail the influence of fan flow on energy and pollutant removal efficiencies of the tunnel ventilation and to evaluate accuracy of CFD studies on fan improvements.

  6. Literature review and experimental investigation of heat pipes

    Barsch, W. O.; Schoenhals, R. J.; Viskanta, R.; Winter, E. R. F.


    Tests on heat pipes determine operational limits, external boundary conditions, noncondensable gas effects, startup behavior, and geometric configurations. Experiment consists of design, construction, and testing of an apparatus for measuring wick properties, conventional heat pipes and coplanar heat pipes.

  7. Altered collecting duct adenylyl cyclase content in collecting duct endothelin-1 knockout mice

    Kohan Donald E


    Full Text Available Abstract Background Endothelin-1 (ET-1 inhibition of vasopressin (AVP-stimulated water reabsorption by the inner medullary collecting duct (IMCD is associated with reduced cAMP accumulation. To determine the effect of ET-1 deficiency, AVP-stimulated cAMP responsiveness was assessed in IMCD from mice with collecting duct-specific deletion of ET-1 (CD ET-1 KO and from control animals. Methods Cyclic AMP production, adenylyl cyclase (AC mRNA, and AC protein were measured in acutely isolated IMCD. Results CD ET-1 KO IMCD had enhanced AVP-stimulated cAMP accumulation. Inhibition of calcium-stimulated AC using BAPTA did not prevent enhanced AVP responsiveness in CD ET-1 KO IMCD. Factors known to be modified by ET-1, including nitric oxide, cyclooxygenase metabolites, and superoxide did not affect the increased AVP responsiveness of CD ET-1 KO IMCD. Differential V2 receptor or G-protein activity was not involved since CD ET-1 KO IMCD had increased cAMP accumulation in response to forskolin and/or cholera toxin. CD ET-1 KO did not affect mRNA or protein levels of AC3, one of the major known collecting duct AC isoforms. However, the other known major collecting duct AC isoform (AC5/6 did have increased protein levels in CD ET-1 KO IMCD, although AC5 (weak signal and 6 mRNA levels were unchanged. Conclusion ET-1 deficiency increases IMCD AC5/6 content, an effect that may synergize with acute ET-1 inhibition of AVP-stimulated cAMP accumulation.

  8. Large Eddy Simulation of turbulent heat transfer in a rotating square duct

    Qin, Zhaohui; Pletcher, Richard


    Turbulent heat transfer in a rotating square duct is an important topic with numerous applications such as turbine blade cooling and automobile brake cooling. Without rotation, Prandtl's secondary flow of the second kind is known to have a significant impact on the transport of heat and momentum in turbulent duct flows. With rotation, Coriolis force and centrifugal buoyancy force cause more complicated secondary flow pattern and, as a consequence, modify heat transfer coefficients. The objective of this study is to expand the capability of the current LES code to correctly predict complex turbulent flow phenomena and to gain a better understanding of the physics of turbulent flow in rotating passages. A finite volume LU-SGS scheme is used to simulate compressible three-dimensional turbulent flow at low Mach numbers. Time derivative preconditioning is employed to deal with the low Mach number situation. A localized dynamic subgrid-scale (SGS) model is used to evaluate the unresolved stresses. The calculation domain is divided into two parts. In the first part periodic boundary conditions are applied and this provides the fully developed inlet flow for the second part in which the heat transfer conditions are imposed. Characteristic out-flow conditions are used in the second part. This allows the flow to develop further as it responds to the heating condition. The code is parallelized using MPI (Message Passing Interface). To verify the code, we calculated isothermal rotating duct cases and compared our results with DNS and experimental results. Then heated duct flow cases were simulated and the results were compared to available data. Good agreement has been obtained.

  9. Fully developed turbulence in slugs of pipe flows

    Cerbus, Rory; Liu, Chien-Chia; Sakakibara, Jun; Gioia, Gustavo; Chakraborty, Pinaki


    Despite over a century of research, transition to turbulence in pipe flows remains a mystery. In theory the flow remains laminar for arbitrarily large Reynolds number, Re. In practice, however, the flow transitions to turbulence at a finite Re whose value depends on the disturbance, natural or artificial, in the experimental setup. The flow remains in the transition state for a range of Re ~ 0 (1000) ; for larger Re the flow becomes fully developed. The transition state for Re > 3000 consists of axially segregated regions of laminar and turbulent patches. These turbulent patches, known as slugs, grow as they move downstream. Their lengths span anywhere between a few pipe diameters to the whole length of the pipe. Here we report Stereo Particle Image Velocimetry measurements in the cross-section of the slugs. Notwithstanding the continuous growth of the slugs, we find that the mean velocity and stress profiles in the slugs are indistinguishable from that of statistically-stationary fully-developed turbulent flows. Our results are independent of the length of the slugs. We contrast our results with the well-known work of Wygnanski & Champagne (1973), whose measurements, we argue, are insufficient to draw a clear conclusion regarding fully developed turbulence in slugs.

  10. New DNS and modeling results for turbulent pipe flow

    Johansson, Arne; El Khoury, George; Grundestam, Olof; Schlatter, Philipp; Brethouwer, Geert; Linne Flow Centre Team


    The near-wall region of turbulent pipe and channel flows (as well as zero-pressure gradient boundary layers) have been shown to exhibit a very high degree of similarity in terms of all statistical moments and many other features, while even the mean velocity profile in the two cases exhibits significant differences between in the outer region. The wake part of the profile, i.e. the deviation from the log-law, in the outer region is of substantially larger amplitude in pipe flow as compared to channel flow (although weaker than in boundary layer flow). This intriguing feature has been well known but has no simple explanation. Model predictions typically give identical results for the two flows. We have analyzed a new set of DNS for pipe and channel flows (el Khoury et al. 2013, Flow, Turbulence and Combustion) for friction Reynolds numbers up to 1000 and made comparing calculations with differential Reynolds stress models (DRSM). We have strong indications that the key factor behind the difference in mean velocity in the outer region can be coupled to differences in the turbulent diffusion in this region. This is also supported by DRSM results, where interesting differences are seen depending on the sophistication of modeling the turbulent diffusion coefficient.

  11. Pipe flow of pumping wet shotcrete based on lubrication layer.

    Chen, Lianjun; Liu, Guoming; Cheng, Weimin; Pan, Gang


    Wet shotcrete can reduce dust and improve supporting strength, however, safe and efficient pipage is a key technical part of wet shotcrete process. The paper studied the pipe flow law of wet shotcrete based on lubrication layer by build the experimental pumping circuit of wet shotcrete that can carry out a number of full-scale pumping tests. The experimental results show there was a linear relationship between pressure loss and flow rate. Combined with the Buckingham rheological equation, the computing equations of the yield shear stress and plastic viscosity were deduced through linear regression. A simple analytical method allowing for a rough estimation of the pumping pressure was proposed and used when considering the lubrication layer of wet shotcrete in pipes. In addition, two kinds of particulate distributive models were established along the time axial to analyze the formation of lubrication layer which is related with particles migration. By computational fluid dynamics simulation, the lubrication layer thickness of different mix proportions was estimated. A new method for measuring the thickness of lubrication layer was proposed to verify it by binarization processing. Finally, according to the comparative analysis of experiments, simulation and computed value, it can be seen that the lubrication layer plays a key role in the process of wet shotcrete flow and with the increase of lubrication layer thickness pipe pressure declines gradually.

  12. Pipe Poiseuille flow of viscously anisotropic, partially molten rock

    Allwright, Jane


    Laboratory experiments in which synthetic, partially molten rock is subjected to forced deformation provide a context for testing hypotheses about the dynamics and rheology of the mantle. Here our hypothesis is that the aggregate viscosity of partially molten mantle is anisotropic, and that this anisotropy arises from deviatoric stresses in the rock matrix. We formulate a model of pipe Poiseuille flow based on theory by Takei and Holtzman [2009a] and Takei and Katz [2013]. Pipe Poiseuille is a configuration that is accessible to laboratory experimentation but for which there are no published results. We analyse the model system through linearised analysis and numerical simulations. This analysis predicts two modes of melt segregation: migration of melt from the centre of the pipe toward the wall and localisation of melt into high-porosity bands that emerge near the wall, at a low angle to the shear plane. We compare our results to those of Takei and Katz [2013] for plane Poiseuille flow; we also describe a ne...

  13. Fitness for service assessment of degraded CANDU feeder piping-Canadian regulatory expectations

    Jin, John C., E-mail: john.jin@cnsc-ccsn.gc.c [Operational Engineering Assessment Div., Canadian Nuclear Safety Commission (Canada); Awad, Raoul [Operational Engineering Assessment Div., Canadian Nuclear Safety Commission (Canada)


    Allowance for the continued operation of feeder piping at some Canadian CANDU stations, which is experiencing active degradation mechanisms, has been based primarily on augmented inspection practices and conservative fitness for service assessments. The major degradation mechanisms identified to date are: pipe wall thinning due to Flow Accelerated Corrosion (FAC) and service induced cracking due to Intergranular Cracking due to Stress Corrosion Cracking (SCC) and potentially Low Temperature Creep Cracking (LTCC) mechanisms. Given that currently available industry codes and standards do not provide sufficient guidelines/criteria for assessing the degradation of feeder pipes, the Canadian Nuclear Safety Commission (CNSC) has asked the utilities to establish feeder pipe specific procedures to provide reasonable assurance that the risk associated with the feeder degradation is maintained at an acceptably low level. In response to this requirement, the Canadian CANDU industry has developed and continued to update feeder fitness for service guidelines to provide evaluation procedures and industry standard acceptance criteria for assessing the structural integrity of the feeder pipes. The scope and frequency of inspections are determined based on the results of the fitness for service assessments taking into account the relative susceptibility of feeder pipes to each specific degradation mechanism. While industry practices for the management of degraded feeder pipes have, in general, been complied with the regulatory expectations, outstanding issues still remain. Major regulatory concerns include uncertainties associated with limitations in both the inspection techniques and the mechanistic understanding of the degradation processes, which can impede inspection planning and fitness for service assessments. This paper presents the regulator's view of the current situation with respect to degradation of feeder piping, its implications for nuclear safety and the

  14. Effect of vibration loading on the fatigue life of part-through notched pipe

    Mittal, Rahul [Nuclear Power Corporation of India Limited, Mumbai (India); Singh, P.K., E-mail: [Bhabha Atomic Research Centre, Mumbai (India); Pukazhendi, D.M. [Structural Engineering research Centre, Chennai (India); Bhasin, V.; Vaze, K.K.; Ghosh, A.K. [Bhabha Atomic Research Centre, Mumbai (India)


    A systematic experimental and analytical study has been carried out to investigate the effect of vibration loading on the fatigue life of the piping components. Three Point bend (TPB) specimens machined from the actual pipe have been used for the evaluation of Paris constants by carrying out the experiments under vibration + cyclic and cyclic loading as per the ASTM Standard E647. These constants have been used for the prediction of the fatigue life of the pipe having part-through notch of a/t = 0.25 and aspect ratio (2c/a) of 10. Predicted results have shown the reduction in fatigue life of the notched pipe subjected to vibration + cyclic loading by 50% compared to that of cyclic loading. Predicted results have been validated by carrying out the full-scale pipe (with part-through notch) tests. Notched pipes were subjected to loading conditions such that the initial stress-intensity factor remains same as that of TPB specimen. Experimental results of the full-scale pipe tests under vibration + cyclic loading has shown the reduction in fatigue life by 70% compared to that of cyclic loading. Fractographic examination of the fracture surface of the tested specimens subjected to vibration + cyclic loading have shown higher presence of brittle phases such as martensite (in the form of isolated planar facets) and secondary micro cracks. This could be the reason for the reduction of fatigue life in pipe subjected to vibration + cyclic loading. - Highlights: > Vibration loading affects fatigue crack growth rate. > Crack initiation life depends on crack tip radius. > Crack initiation life depends on the characteristic distance. > Characteristic distance depends on the loading conditions. > Vibration + cyclic load gives lower fatigue life.

  15. Transcatheter stenting of arterial duct in duct-dependent congenital heart disease

    Đukić Milan


    Full Text Available Introduction. Critical congenital heart diseases (CHD are mostly duct-dependent and require stable systemic-pulmonary communication. In order to maintain patency of the ductus arteriosus (DA, the first line treatment is Prostaglandin E1 and the second step is the surgical creation of aortic-pulmonary shunt. To reduce surgical risk in neonates with the critical CHD, transcatheter stenting of DA can be performed in selected cases. Case Outline. A four-month old infant was diagnosed with the pulmonary artery atresia with ventricular septal defect (PAA/VSD. The left pulmonary artery was perfused from DA, and the right lung through three major aortopulmonary collaterals (MAPCAs. A coronary stent was placed in the long and critically stenotic DA, with final arterial duct diameter of 3.5 mm, and significantly increased blood supply to the left lung. After the procedure, the infant’s status was improved with regard to arterial oxygen saturation, feeding and weight gain. During the follow-up, one year later, aortography revealed in-stent stenosis. The left pulmonary artery, as well as the branches, was well-developed and the decision was made to proceed with further surgical correction. Conclusion. Stenting of DA can be an effective alternative to primary surgical correction in selected patients with duct-dependent CHD.

  16. HeatTransfer Coefficients and Pressure Drops of The Finned Tube Heat Exchangers with Small Diameter Pipes

    Tanaka, Hiroyoshi; Aoyama, Shigeo; Koma, Hachirou; Adachi, Masaaki

    In order to enhance the heat transfer coefficient of the fin used in the finned tube heat exchanger, newly designed fin surfaces, especially, with small diameter (≅4mm) pipes are developed. The experiments are made by the transient testing technique, and used the plastic fins scaling up 4 times of the actual metal fin size. The data of the heat transfer coefficient and the pressure drop are transformed to the actual metal fin data. The fin with the anomalous staggered pipe arrangement and the bridge-like cutting-out with inclined leg portion from stream line is found to have very high overall heat transfer coefficient which is about 1.8-fold increase in comparison with the conventional Louvered fin. In this paper the reason why such enhancement is caused is clarified by mean of the calculation based on the rectangular duct flow. The calculated values are coincident with the data of the experiment well.

  17. Radon penetration of concrete slab cracks, joints, pipe penetrations, and sealants

    Nielson, KK; Rogers, VC; Holt, RB; Pugh, TD; Grondzik, WA; deMeijer, RJ


    Radon movement through 12 test slabs with different cracks, pipe penetrations, cold joints, masonry blocks, sealants, and tensile stresses characterized the importance of these anomalous structural domains, Diffusive and advective radon transport were measured with steady-state air pressure differen

  18. Heat Pipe with Axial Wick

    Ambrose, Jay H. (Inventor); Holmes, Rolland (Inventor)


    A heat pipe has an evaporator portion, a condenser portion, and at least one flexible portion that is sealingly coupled between the evaporator portion and the condenser portion. The flexible portion has a flexible tube and a flexible separator plate held in place within the flexible tube so as to divide the flexible tube into a gas-phase passage and a liquid-phase artery. The separator plate and flexible tube are configured such that the flexible portion is flexible in a plane that is perpendicular to the separator plate.

  19. Buckling Characteristics of Cylindrical Pipes

    Toshiaki Sakurai


    This paper describes the buckling pattern of the body frame by energy absorbed efficiency of crashworthiness related toresearch of the buckling characteristics of aluminum cylindrical pipes with various diameters formed mechanical tools. Experimentswere performed by the quasi-static test without lubrication between specimen and equipment. According to the change in the radiusversus thickness of the specimen, the buckling phenomena are transformed from folding to bellows and the rate of energy absorptionis understood. In crashworthiness, frames are characterized by the folding among three patterns from the absorbed energy efficiencypoint of view and weight reduction. With the development of new types of transport such as electric vehicles, innovated bodystructure should be designed.

  20. Casing pipe damage detection with optical fiber sensors: a case study in oil well constructions

    Zhou, Zhi; He, Jianping; Huang, Minghua; He, Jun; Ou, Jinping; Chen, Genda


    Casing pipes in oil well constructions may suddenly buckle inward as their inside and outside hydrostatic pressure difference increases. For the safety of construction workers and the steady development of oil industries, it is critically important to measure the stress state of a casing pipe. This study develops a rugged, real-time monitoring, and warning system that combines the distributed Brillouin Scattering Time Domain Reflectometry (BOTDR) and the discrete fiber Bragg grating (FBG) measurement. The BOTDR optical fiber sensors were embedded with no optical fiber splice joints in a fiber reinforced polymer (FRP) rebar and the FBG sensors were wrapped in epoxy resins and glass clothes, both installed during the segmental construction of casing pipes. In-situ tests indicate that the proposed sensing system and installation technique can survive the downhole driving process of casing pipes, withstand a harsh service environment, and remain in tact with the casing pipes for compatible strain measurements. The relative error of the measured strains between the distributed and discrete sensors is less than 12%. The FBG sensors successfully measured the maximum horizontal principal stress with a relative error of 6.7% in comparison with a cross multi-pole array acoustic instrument.